Conventional Forces can Explain the Anomalous Acceleration of Pioneer 10
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关于飞机种类的单词100个英文全文共6篇示例,供读者参考篇1Types of AirplanesHi friends! Today we're going to learn about all the different kinds of airplanes that exist. Airplanes are super cool flying machines that can take us anywhere in the world. There are so many types that it might get a little confusing, but don't worry - I'll do my best to explain them all simply. Get ready for an awesome airplane adventure!First up, let's talk about airliners. These are the huge planes that carry hundreds of people across countries and oceans. Famous airliners include the Boeing 747 which is one of the biggest篇2The Fascinating World of AirplanesHave you ever looked up at the sky and watched a plane soaring high above? Airplanes are amazing machines that allow us to travel vast distances quickly and comfortably. But did youknow that there are many different types of airplanes? Each one is designed for a specific purpose, and they come in all shapes and sizes. Let's explore the fascinating world of airplanes together!Commercial AirlinersThese are the big planes you typically see at airports when you go on a family vacation. They can carry hundreds of passengers and their luggage across countries and even oceans. Some popular commercial airliners are the Boeing 737, the Airbus A320, and the Boeing 787 Dreamliner. These planes are built for comfort and efficiency, with spacious cabins, entertainment systems, and excellent fuel economy.Fighter JetsFighter jets are the speed demons of the sky. They are designed for military use and can reach incredible speeds, often faster than the speed of sound! Some well-known fighter jets are the F-16 Fighting Falcon, the F-22 Raptor, and the F-35 Lightning II. These planes are built for speed, agility, and combat operations, with powerful engines and advanced weapons systems.Cargo PlanesHave you ever wondered how all those packages and parcels get delivered around the world? Cargo planes are the unsung heroes that make it happen. These massive aircraft can carry tons of cargo, from electronics to vehicles and even heavy machinery. Some of the largest cargo planes are the Antonov An-225 Mriya, the Boeing 747 Freighter, and the Airbus A300-600ST Beluga.Private JetsWhile commercial airliners are for the masses, private jets cater to those who want a more exclusive and luxurious flying experience. These sleek and stylish planes can carry only a handful of passengers but offer the ultimate in comfort and privacy. Some popular private jets are the Gulfstream G650ER, the Bombardier Global 7500, and the Embraer Praetor 600.HelicoptersNot all aircraft have wings! Helicopters are unique in that they use rotating blades to generate lift and thrust, allowing them to take off and land vertically. They are incredibly versatile and can perform tasks that fixed-wing aircraft cannot, such as hovering, flying low and slow, and navigating tight spaces. Some well-known helicopters are the Bell 206 JetRanger, the Sikorsky UH-60 Black Hawk, and the Eurocopter EC135.DronesWhile drones are often associated with military applications, they have become increasingly popular for civilian use as well. These unmanned aerial vehicles (UAVs) can be controlled remotely or programmed to fly autonomously. They come in various sizes, from tiny quadcopters to large fixed-wing drones, and are used for tasks like photography, surveillance, and package delivery. Some popular drone models are the DJI Mavic Pro, the Parrot Anafi, and the Autel Robotics EVO II.Experimental and Futuristic DesignsThe aviation industry is constantly pushing the boundaries of what's possible, and there are many experimental and futuristic aircraft designs in the works. Some examples include the Lockheed Martin X-59 QueSST, a quiet supersonic jet, and the NASA X-57 Maxwell, an all-electric airplane designed for efficiency and sustainability. There are also concepts for flying cars, hypersonic planes, and even aircraft that can take off and land vertically like a helicopter but fly like a conventional plane.As you can see, the world of airplanes is vast and fascinating. From the massive commercial airliners that transport millions of people every day to the sleek and speedy fighter jets and the versatile helicopters, each type of aircraft serves a uniquepurpose. Who knows what the future holds for aviation? Perhaps one day, we'll all be zooming around in our own personal flying cars or taking supersonic flights to distant destinations. The sky is truly the limit!篇3Types of AirplanesAirplanes are really cool machines that can fly through the sky! There are many different kinds of airplanes used for different purposes. Some airplanes are huge and can carry hundreds of people. Other airplanes are tiny and meant for just one or two people to fly. Let me tell you about some of the most common types of airplanes!Passenger AirlinersThe airplanes that most people are familiar with are passenger airliners. These are the big planes that you take when going on a trip or vacation. Passenger airliners can range from small regional jets that seat around 50 people to giantwide-body jets that can hold over 500 passengers! Some of the most popular airliners are the Boeing 737, Boeing 777, AirbusA320, and Airbus A380 super-jumbo jet.Fighter JetsFighter jets are super fast military planes used by air forces around the world. They are built for speed and maneuverability to allow them to dogfight with enemy aircraft. Famous fighter jets include the F-16 Fighting Falcon, F-22 Raptor, F-35 Lightning II, and the Russian Su-27 Flanker. Fighter jets can fly at twice the speed of sound!Cargo AirplanesTo transport large amounts of cargo and freight, airlines and companies use dedicated cargo airplanes. These have a big front door that opens up to allow loading and unloading of containers, vehicles, and pallets of boxes. The Boeing 747 FreighterFedEx and UPS use lots of these! Some cargo planes actually had the passenger cabin removed so they can fit more stuff inside.Private JetsFor rich people and celebrities who want to fly in luxury, private jets are the way to go. These small jets typically seat less than 20 people and have amenities like leather seats, entertainment systems, and even bedrooms! Popular private jet models are the Gulfstream G650, Bombardier Global 7500, and Embraer Legacy 500.Propeller AirplanesNot all planes have jets! Many smaller aircraft use propellers to generate thrust, just like the Wright Brothers' first airplane. Propeller planes range from tiny single-engine planes used for training, to bigger turboprop airliners like the Dash 8 that can carry 70 passengers. Propeller planes are good for short flights as they are more fuel efficient than jets.Military TransportsThe military needs ways to transport troops, vehicles, supplies and equipment around the world. That's where military transport aircraft come in! These are super heavy airplanes built tough to land on rough airfields. Famous military transports are the C-17 Globemaster III, the C-5 Galaxy, and the Russian Antonov An-124 which can haul over 100 tons!Experimental AircraftSome airplanes are built just for testing out new designs and technologies. NASA and aircraft companies build experimental planes with crazy shapes, like the X-planes tested by the US Air Force and companies like Boeing and Lockheed Martin. These aircraft help come up with innovations for future passenger and military planes.As you can see, there are all sorts of airplanes made for different missions and purposes. From small trainers to gigantic cargo haulers, each type of aircraft is specially designed for its role. Isn't it amazing the different ways that engineers can design machines to conquer the skies? Aviation is a wonderful field full of awesome flying vehicles!篇4The Wonderful World of AirplanesHave you ever looked up at the sky and seen an airplane flying high above? Airplanes are incredible machines that allow us to travel huge distances across the world in a matter of hours. But did you know that there are many different types of airplanes designed for various purposes? Let me introduce you to some of the most fascinating airplanes out there!Commercial AirlinersThese are the big planes you've probably seen at airports. They're designed to carry lots of passengers and cargo over long distances. Some examples are the Boeing 747, the Airbus A380, and the Boeing 777. The 747 is one of the most recognizable planes with its iconic hump on the top. The A380 is even bigger and is the largest passenger airplane in the world! It has two fulldecks and can carry over 800 passengers. Commercial airliners are like big buses in the sky.Fighter JetsThese sleek and powerful airplanes are made for speed and agility. Fighter jets like the F-22 Raptor and the F-35 Lightning II are used by military forces for air combat and bombing missions. They're incredibly fast, with some able to fly over twice the speed of sound! Fighter jets have advanced weapons systems and can perform incredible maneuvers that civilian planes can't.Cargo PlanesAs the name suggests, these huge planes are used to transport large amounts of cargo like food, vehicles, and other goods. Some well-known cargo planes are the Boeing 747 Freighter, the Antonov An-124, and the C-5 Galaxy. The An-124 is one of the largest cargo planes and can carry over 100 tons of cargo! Cargo planes have a big front door that opens up so that containers and vehicles can be loaded and unloaded easily.Private JetsWhile not as big as commercial airliners, private jets are luxurious and designed for the comfort of a small number of passengers. Some examples are the Gulfstream G650, theBombardier Global 7500, and the Cessna Citation X+. These planes often have plush leather seats, entertainment systems, and even bedrooms and bathrooms. Many wealthy individuals and corporations own private jets for business and leisure travel.HelicoptersUnlike airplanes, helicopters can take off and land vertically without needing a runway. They have large rotors on top that spin and provide the lift needed to fly. Some popular helicopters are the Bell 206 JetRanger, the Sikorsky UH-60 Black Hawk, and the AgustaWestland AW139. Helicopters are very versatile and are used for things like transporting people and equipment, firefighting, search and rescue, and even in military operations.That's just a small taste of the incredible variety of airplanes out there! From massive cargo haulers to lightning-fast fighter jets, these amazing machines allow us to conquer the skies in ways that would have seemed impossible just a century ago. Who knows what new and exciting airplanes the future will bring? The sky's the limit!篇5Airplanes: The Amazing Flying MachinesDo you ever look up at the sky and see an airplane soaring high above? Airplanes are incredible machines that can fly through the air and take us to amazing places all over the world. There are so many different types of airplanes, each one designed for a special purpose. Let me tell you all about them!Commercial AirlinersThese are the big planes that carry lots of passengers from one city to another. Some of the most common ones are the Boeing 737 and the Airbus A320. They have two engines and can seat over 150 people. When you go on a family vacation and fly somewhere, you'll probably be on one of these airliners.Regional JetsRegional jets are smaller airplanes that fly shorter routes, like between nearby cities. They only have around 50 seats. Some examples are the Bombardier CRJ and the Embraer E-Jet. These planes are perfect for quick trips without having to use a huge airliner.TurbopropsTurboprops look a bit different because they have propellers instead of jet engines. But don't be fooled – they are still very modern airplanes! The propellers give them better fuel efficiencyfor shorter flights. Common turboprops are the Dash 8 and the ATR 72.Private JetsWhile big airliners carry hundreds of people, private jets are luxurious small planes for just a handful of passengers. They are super fancy inside with leather seats and other premium amenities. The Cessna Citation and the Gulfstream G650 are two examples of these sleek corporate jets.Cargo PlanesHave you ever wondered how all those boxes you order online get delivered so quickly? The answer is cargo planes! These are huge aircraft designed to carry heavy loads of freight and packages. Popular ones include the Boeing 747 Freighter and the Airbus A300-600ST Beluga.Fighter JetsNow these are the coolest airplanes of all – fighter jets used by the military! They are extremely fast and maneuverable. Famous fighter jets are the F-22 Raptor, the F-35 Lightning II, and the F/A-18 Super Hornet. These incredible aircraft can reach supersonic speeds and pull off amazing aerial stunts.There are so many more types like helicopters, seaplanes, gliders, and even experimental solar planes. The world of aviation is very diverse and exciting. Who knows what amazing new aircraft designs the future will bring? Maybe one day you'll even become a pilot yourself and get to fly these incredible machines!篇6Types of AirplanesHave you ever looked up at the sky and seen an airplane flying high above? Airplanes are amazing machines that can soar through the air and take us to exciting places around the world. But did you know that there are many different types of airplanes? Each one is designed for a specific purpose, and they come in all shapes and sizes. Let me tell you about some of the most common kinds of airplanes you might see.Commercial AirlinersThese are the big airplanes that carry lots of passengers from one city to another. Companies like American Airlines, United Airlines, and Delta operate these jets. They have two or four engines and can fly very far distances. Some of the mostwell-known commercial airliners include the Boeing 737, Boeing747 (also called the "Jumbo Jet"), and the Airbus A320. When you go on a family vacation and fly somewhere, you'll likely be on one of these airliners.Private JetsWhile commercial airliners carry hundreds of people, private jets are much smaller and transport just a few passengers at a time. Many wealthy individuals and celebrities own private jets to travel in luxury and privacy. Some examples are the Cessna Citation, Gulfstream G650, and Bombardier Global Express. These sleek planes have fancy interiors with comfortable seating and amenities.Fighter JetsFighter jets are super fast military airplanes used by the Air Force. Their job is to defend our country's airspace and attack enemy targets. The F-22 Raptor, F-35 Lightning, and F-16 Fighting Falcon are a few of the high-tech fighter jets flown by U.S. pilots. With their powerful engines and cool-looking designs, fighter jets can reach incredible speeds!Cargo PlanesWhen you order a toy or clothes online, those items are likely delivered to your home by truck. But how did they getacross the country so quickly? Big cargo planes carried those packages! Companies like FedEx and UPS use giant cargo planes like the Boeing 747 freighter to transport millions of parcels every day. These planes are built without passenger seats to maximize space for shipping containers full of boxes.HelicoptersUnlike airplanes that need a runway, helicopters can take off and land vertically. Their spinning rotor blades allow them to hover in the air. Police departments use helicopters to monitor the streets from above. News stations rely on helicopters to capture video footage of major events. And health care workers fly helicopters to rescue injured people in remote areas and bring them to hospitals. The most common helicopters are the Bell 206, Sikorsky UH-60 Blackhawk, and the AgustaWestland AW139.Small PlanesFor people who want to fly themselves instead of being a passenger, small planes are the way to go. These light aircraft include single-engine or twin-engine propeller planes. Popular models are the Cessna 172, Piper Cherokee, and Cirrus SR22. Many small airports have flight schools that teach people how to be pilots and let them practice flying these planes.There are so many other types of airplanes too – from crop dusters that spray fields on farms to aerobatic planes that perform stunts and tricks in the sky. Airplanes allow us to travel around the globe quickly and easily. They help ship goods, protect our country, and let people experience the wonder of flight. The next time you see an airplane overhead, watch closely and see if you can identify what kind it is! Our skies are filled with all sorts of amazing aircraft.。
我的梦想英语作文,物理学家Since my early childhood, I have been captivated by the mysteries of the universe. The stars twinkling in the night sky, the intricate patterns of nature, and the fundamental laws that govern our world have always fascinated me. This deep-seated curiosity has shaped my dream to become a physicist. Physics is not just a subject for me; it is a gateway to understanding the complexities of reality and unraveling the secrets of existence.The journey towards becoming a physicist is a challenging yet rewarding one. I envision myself pursuing advanced studies in theoretical physics, where I can delve into concepts like quantum mechanics, relativity, and the fundamental forces of nature. These theories not only explain how the universe operates but also challenge our perceptions of space, time, and matter. I aspire to contribute togroundbreaking research that could redefine our understanding of the universe as we know it.One of my main inspirations comes from the work of renowned physicists like Albert Einstein and Stephen Hawking. Their relentless pursuit of knowledge and ability to think beyond conventional boundaries motivates me to push my own limits. I have spent countless hours reading about their experiments and theories, and I am particularly drawn to Hawking's exploration of black holes and the nature of time.I dream of one day making a similar impact in the field, whether it be through new discoveries or innovative theories that inspire future generations.In addition to theoretical research, I also believe in the importance of practical application. I hope to collaborate with engineers and researchers to develop technologies that harness the principles of physics for societal benefit. Energy solutions, medical technologies, andadvancements in materials science are just a few areas where physics plays a crucial role. By bridging the gap between theory and application, I aim to contribute to solving someof the pressing challenges faced by humanity.Moreover, I wish to share my passion for physics with others. Teaching empowers me to inspire young minds and encourage them to explore the wonders of the universe. I believe that when students grasp the beauty of physics, it sparks their creativity and critical thinking skills. I envision myself not only as a researcher but also as an educator, fostering a love for science in the next generation.In conclusion, my dream of becoming a physicist is fueled by an insatiable curiosity about the universe and a desire to make meaningful contributions to both science and society. I am committed to pursuing this path, embracing both the challenges and opportunities it presents. Through my journey, I hope to unlock new secrets of the universe and inspireothers to join me in exploring the magnificent world of physics.。
itistimedidshoulddo和itistimetodo的区别it is time did/should do和it is time to do的区别区别是:It is time did/should do表示到了做..的时间,但是强调没有做/发生。
It is time to 表示提出建议,到做某事的时间了。
例句辨析:It is time did/should do1、For *** s, may be it is time we should consider hula hooping too.对于成年人,可能现在是时候我们应该考虑呼啦胡平了。
2、It is high time I should go home now.现在正是我回家的时间了。
3、It is high time he should e to our house for dinner.已经到了他该上咱家吃晚饭的时候了。
4、I think it is high time I should review my modes of behaving and manners of talking.我想我也应该重新审视我平时为人处事的方式,还有我的言谈举止。
It is time to1、I believe it is time to ban tobao advertising altogether.我认为该完全禁止烟草广告了。
2、All Italy's political parties have aepted that it is time to revamp the system.所有的意大利政党都已经承认现在是时候对体制进行改组了。
3、It is time to bury our past misunderstandings.是我们捐弃前嫌的时候了。
4、It is time to go beyond the shibboleth that conventional forces cannot deter.是时候摆脱那些传统力量无法遏制的陈规陋习了。
机械英语-齿轮英语句子和术语一、齿轮英语句子1. At first, based on the analysis of the character of the tooth profile of Archimedes worm wheel, we prove that there is a unique common normal to the whole profile本文首先从分析阿基米德蜗轮齿面特性出发,论述了阿基米德蜗轮公法线在蜗轮齿面上的唯一性,并推导了阿基米德蜗轮公法线计算公式;2. It is important to ensure that the anchorage point can withstand the forces applied的。
3. Knowing the strength, it is possible to work backward and determine what factor of 由于知道其强度,便可以反过来求出所用的安全系数值。
4.Safe load capacity, strengths and application limits of accessories and components5.The deformation significantly increases electron mobility, making it possible to boost computer speed and reduce energy consumption.6.Although the cycloidal gear has much merits , the pure cycloidal gear is less used in正摆线齿轮。
7.Based on the tooth profile curve equation of inner rotors in cycloidal pump, the根据摆线泵内转子的齿廓曲线方程,推导出了摆线泵的排量计算公式。
高中英语哲学思想单选题30题1. In philosophy, the term "metaphysics" is often associated with the study of _____.A. physical phenomenaB. abstract conceptsC. observable factsD. practical applications答案:B。
本题考查哲学名词“metaphysics( 形而上学)”相关的知识。
选项A“physical phenomena( 物理现象)”侧重于物质世界的具体现象,与形而上学研究的抽象概念不符。
选项B“abstract concepts( 抽象概念)”符合形而上学的研究范畴,形而上学主要探讨超越感官经验的抽象本质和原理。
选项C“observable facts 可观察的事实)”通常是实证研究的对象,而非形而上学的重点。
选项D“practical applications( 实际应用)”更侧重于实际操作和具体用途,与形而上学的理论性质不同。
2. The philosopher sought to ______ the essence of human existence.A. defineB. ignoreC. misunderstandD. complicate答案:A。
此题考查哲学动词的运用。
选项A“define( 定义)”符合哲学家探索人类存在本质的目的,即试图给出明确的定义和解释。
选项B“ignore忽视)”与哲学家的研究态度相悖。
选项C“misunderstand( 误解)”不是哲学家追求的目标。
选项D“complicate 使复杂化)”与寻找本质的初衷不符,哲学家通常是为了简化和清晰化概念。
3. Philosophy often deals with ______ questions that challenge conventional wisdom.A. controversialB. simpleC. obviousD. unimportant答案:A。
历年真题09年Text 1Habits are a funny thing. We reach for them mindlessly, setting our brains on auto-pilot and relaxing into the unconscious comfort of familiar routine. “No choice, but habbit rules the the unreflecting herd,”William Wordsworth said in the 19th century. In the ever-changing 21st century, even the word “habbit” carries a negative implication.So it seems paradoxical to talk about habits in the same context as creativity and innovation. But brain researchers have discovered that when we consciously develop new habits, we create parallel paths, and even entirely new brain cells, that can jump our trains of thought onto new, innovative tracks.Rather than dismissing ourselves as unchangeable creatures of habbit, we can instead direct our own change by consciously developing new habits. In fact, the more new things we try----the more we step outside our our comfort zone—the more inherently creative as we become, both in the workplace and in our personal lives. But don't bother trying to kill off old habbits; once those ruts of procedure are worn into the brain, they are there to stay. Instead, the new habbits we deliberately press into ourselves create parallel path-ways that can bypass those old roads.“The first thing needed for innovation is a fascination with wonder,”says Dawna Markova, author of The open Mind. “But we are taught instead to “decide”, just as our president calls himself “the Decider”.”She adds, however, that “to decide is to kill off all possibilities but one. A good innovational thinker is always exploring the many other possibilities.”All of us work through problems in ways of which we are unaware, she says. Reseachers in the late 1960s discovered that humans are born with the capacity to approach challenges in four primary ways:analyticallly, procedurally,relationally(or collaboratively) and innovatively. At the end of adolescence, however, the brain shuts down half of that capacity, preserving only those modes of thought that have seemed most valuable during the first decade or so of life.1.In Wordsworth’s view, “habit” is characterized by beingA. casualB. familiarC. mechanicalD.challengeable2. Brain researchers have discovered that the formation of new habit can beA. predictedB. regulatedC.tracedD. guided3. the word “ruts”(line 1, paragraph 4”is closest in meaning toA. tracksB. seriesC. characteristicsD.connections4. Dawna Markaova would most probably agree thatA. ideas are born of relaxing mind.B. innovativeness could be taught.C. decisiveness derives from fantastic ideas.D. curiosity activates creative minds.5.Ryan’s comments suggest that the practice of standardized testingA. prevents new habits from being formedB. no longer emphasizes commonness.C. maintains the inherenet American thinking modeD. complies with the American belief system.Text 2It is a wise father that knows his won child, but today a man can boost his paternal(fatherly) wisdom---or at least confirm that he is the kid’s dad. All he needs to do is shell our $30 for a paternity testing kit(PIK) at his local drugstore----and another $120 to get the results.More than 60000 people have purchased the PTKs since they first became available without perscriptions last years, according to Doug Fogg, chief operating officer of Identigene, which makes the over-the-counter kits. More than two dozen companies sell DNA tests directly to the public, ranging in price from a few hundred dollars to more than $2500.Among the most pupular: paternity and kinship testing, which adopted children can use to find their biological relatives and families can use to track down kids put up for adoption. DNA testing is also the latest rage among passionate genealogists and supports businesses that offer to search for a family’s geographic roots.Most tests require collecting cells by swabbing saliva in the mouth and sending it to the company for testing. All tests require a potential candidate with whom to compare DNA.But some observers are skeptical. “ There is a kind of false precision being hawked by people claiming they are doing ancestry testing,”says Trony duster, a New York University sociologist. He notes that each individual has many ancestors----numbering in the hundreds of just a few centuries back. Yet most ancestry testing only considers a single lineage, either the Y Chromosome inherited through men in a father’s line or mitochondrial DNA, which is passed down only from mothers. This DNA can reveal genetic information about only one or two ancestors, even though, for example, just three generations back people also have six other great-grandparents or, four generations back, 14 other great-great-grandparents.Critics also argue that commercial genetic testing is only as good as the reference collections to which a sample is compared. Databases used by some companies don't rely on data collected systematically but rather lump together information from different research projects. This means that a DNA database may have a lot of data from some regions and not others, so a person’s test results may differ depending on the company that processes the results. In addition, the computer programs a company uses to estimate relationships may be patented and not subjectto peer review or outside evaluation.1.In paragraph 1 and 2 , the text shows PTK’sA.easy availablityB.flexibility in pricingC.successful promotionD.popularity with households1.PTK is used toA.locate one’s birth place.B.Promote genetic researchC.Identify parent-child kinshipD.Choose children for adoption2.Skeptical observers believe that ancestry testing fails toA.trace distant ancestorsB.rebuild reliable bloodlinessC.fully use genetic information.D.achieve the claimed accuracy.3.In the last paragraph, a problem commercial genetic testing faces isA.disorganized data collection.B.Overlapping database building.C.Excessive sample comparisonck of patent evaluation.4.An appropriate title for the text is most likely to beA.Fors and Againsts of DNA testingB.DNA Testing and Its problemsC.DNA Testing Outside the LabD.Lies Behind DNA TestingText 3The relationship between formal education and economic growth in poor countries is widely misunderstood by economists and politicians alike. Progress in both areas is undoubtedly necessary for the social, political, and intellectual development of these and all other societies; however, the conventional view that education should be one of the very highest priorities for promoting rapid economic development in poor countries is wrong. We are fortunate that it is, because building new educational systems there and putting enough people through them to improve economic performance would require two or three generations. The findings of a research institution have consistently shown that workers in all countries can be trained on the job to achieve radically higher productivity and, as a result, radically higher standards of living.Ironically, the first evidence for this idea appeared in the United Sates. Not long ago, with the country entering a recession and Japan at its pre-bubble peak, the US workforce was dereded as poorly educated and one of the primary causese ofthe poor US ecnomic performance. Japan was, and remains, the global leader in automotive-assembly productivity. Yet the research revealed that the US factories of Honda, Nissan, and Toyota achieved about 95 percent of the productivity of their Japanese counterparts----a result of the training that US workers received on the job.More recently, while examining housing construction, the researchers discovered that illiterate, non-english-speaking Mexican workers in Houston, Texas, consistently met best-practice labor productivity standards despite the complexity of the building industry’s work.What is the real relationship between education and economic develompment? We have to suspect that continuing economic growth promotes the development of education even when governments don't force it. After all, that is how education got started. When our ancestors were hunters and gatherers 10000 years ago, they didn't have time to wonder much about anything besides finding food. Only when humanity began to get its food in a more productivity way was there time for other things.As education improved, humanity’s productivity potential increased as well. When the competitive environment pushed our ancestors to achieve that potential, they could in turn afford more education. This increasingly high level of education is probably a necessary, but not a sufficient, condition for the complex political systems required by advanced economic performance. Thus poor countries might not be able to escape their poverty traps without political changes that may be possible only with broader formal education. A lack of formal education, however, doesn't constrain the ability of the developing world’s workforce to substantially improve productivity for the foreseeable future. On the contrary, constraints on improving productivity explain why education is not developing more quickly there than it is. 5.The author holds in Paragraph 1 that the importance of education in poor countriesA. is subject to groundless doubtsB. has fallen victim of biasC. is conventionally downgraded.D. has been overstimated2. It is stated in paragraph 1 that the constitution of a new educated systemA.challenges economists and politiciansB.takes efforts of generations.C.demands priority from the governemntD.requires sufficient labor force.3. A major difference between the Japanese and US workforces is thatA.the Japanese workforce is better disciplinedB.the Japnesse workforce is more productiveC.the US workforce has a better education.D.The US workforce ismore organized.4.The author quotes the example of our ancestors to shjow that education emergedi.when people had enough timeii.prior to better ways of finding foodiii.when people no longer went hungryiv.as a result of pressure on government2.According to the last paragraph, development of educationi.results in directly from competitive environmentii.does not depend on economic preformanceiii.follows improved productivityiv.can not afford political changesText 4The most thoroughly studied intellectuals in the history of the New World are the ministers and political leaders of seventeenth-century New England. According to the standard history of American Phylosophy, no where else in conlonial America was “so much importance attached to intellectual pursuits.” According to many books and articles, New England’s leaders established the basic themes and preoccupations of an unfolding, dominant Puritan tradition in American intellectual life.To take this approach to the New Englanders normally means to start with the Puretans’theological innovations and their distinctive ideas about the church---important subjects that we may not neglect. But in keeping with our examination of southern intellectual life, we may consider the original Puritans as carriers of European culture, adjusting to New World circumstances. The New England colonies were the scenes of important episodes in the pursuit of widely understood ideals of civility and virtuosity.The early settlers of Massachusettes Bay included men of impressive education and influence in England. Besides the ninety or so learned ministers who came to Massachusettes churches in the decade after 1629, there were political leaders like John Winthrop, an educated gentelman , lawyer, and official of the Crown before he journeyed to Boston. These men wrote and published extensively, reaching both New World and Old World audiences, and giving New Englanders an atmosphere of intellectual earnestness.We should not forget, however, that most New Englander were well educated. While few craftsmen or farmers, let alone dependents and servants, left literary compositions to be analyzed, it is obvious that their views were less fully intelectualized. Their thinking often had a traditional superstitious quality. A tailor named John Dane, who emigrated in the late 1630s, left an account of his reasons for leaving England that is filled with signs. Sexual confusion, economic frustrations, and religious hope---all came together in a decisive moment when he opened the Bible, told his father that the first line he saw would settle his fate, and read the magical words: “Come out from among them, touch no unclean thing, and I will be your God and you shall be my people.” One wonders what Dane thought of the careful sermons explaining the Bible that he hard in puritan churches.Meanwhile, many settles had slighter religious commitemnts than Dane’s, as one clergyman learned in confronting folk along the coast who mocked that they had not come to the New World for religion “Our main end was to catch fish.”1.The author holds that in the seventeenth-century New EnglandA.Purian tradition dominated political lifeB.Intellectual interests were encouragedC.Politics benefited much from intellectual endeavorsD.Intellectual pursuits enjoyed a liberal environment2.It is suggested in Paragraph 2 that New EnglandersA.experienced a comparatively peaceful early historyB.brought with them the culture of the Old WorldC.paid little attention to southern intellectual lifeD.were obsessed with religious innovations3.The early ministers and political leaders in Massachusetts BayA.were famous in the New World for their writingsB.gained increasing importance in religious affairsC.abandoned high positions before coming to the New EnglandD.created a new intellectual atmosphere in New England4.The story of John Dane shows that less well-educated New Englanders were oftenA.influenced by superstitionsB.troubled with religious beliefsC.puzzled by church sermonsD.frustrated with family earnings4.The text suggests that early settlers in New EnglandA.were mostly engaged in political activitiesB.were motivated by an illusory propectC.came from different intellectual backgroundsD.left few formal records for later reference。
2001年全国硕士研究生入学统一考试英语试题SectionII ClozeTestDirections: Foreachnumberedblankinthefollowingpassage,therearefourchoicesmarked[A],[B],[C]and[D].Choosethebesto neandmarkyouransweron ANSWERSHEET1byblackeningthecorrespondingletterinthebracketswithapencil.(10points)Thegovernmentistobanpaymentstowitnessesbynewspapersseekingtobuyuppeopleinvolvedinprominentca sesthetrialofRosemaryWest.“31.32.33.34.35. [A]publicity [B]penalty [C]popularity [D]peculiarity36. [A]since [B]if [C]before [D]as37. [A]sided [B]shared [C]complied [D]agreed38. [A]present [B]offer [C]manifest [D]indicate39. [A]Release [B]Publication [C]Printing [D]Exposure40. [A]storm [B]rage [C]flare [D]flash41. [A]translation [B]interpretation [C]exhibition [D]demonstration42. [A]betterthan [B]otherthan [C]ratherthan [D]soonerthan43. [A]changes [B]make [C]sets [D]turns44. [A]binding [B]convincing [C]restraining [D]sustaining45. [A]authorized [B]credited [C]entitled [D]qualified46.47.48.49.50.AcomparisonofBritishgeologicalpublicationsoverthelastcenturyandahalfrevealsnotsimplyanincreasinge mphasisontheprimacyofresearch,butalsoachangingdefinitionofwhatconstitutesanacceptableresearchpaper.Th us,inthenineteenthcentury,localgeologicalstudiesrepresentedworthwhileresearchintheirownright;but,inthetwe ntiethcentury,localstudieshaveincreasinglybecomeacceptabletoprofessionalsonlyiftheyincorporate,andreflect on,thewidergeologicalpicture.Amateurs,ontheotherhand,havecontinuedtopursuelocalstudiesintheoldway.The overallresulthasbeentomakeentrancetoprofessionalgeologicaljournalsharderforamateurs,aresultthathasbeenre inforcedbythewidespreadintroductionofrefereeing,firstbynationaljournalsinthenineteenthcenturyandthenbyse verallocalgeologicaljournalsinthetwentiethcentury.Asalogicalconsequenceofthisdevelopment,separatejournal shavenowappearedaimedmainlytowardseitherprofessionaloramateurreadership.Arathersimilarprocessofdiffer entiationhasledtoprofessionalgeologistscomingtogethernationallywithinoneortwospecificsocieties,whereastheamateurshavetendedeithertoremaininlocalsocietiesortocometogethernationallyinadifferentway.AlthoughtheprocessofprofessionalisationandspecializationwasalreadywellunderwayinBritishgeologydur ingthenineteenthcentury,itsfullconsequenceswerethusdelayeduntilthetwentiethcentury.Insciencegenerally,ho wever,thenineteenthcenturymustbereckonedasthecrucialperiodforthischangeinthestructureofscience.51. Thegrowthofspecializationinthe19thcenturymightbemoreclearlyseeninsciencessuchas________.[A]sociologyandchemistry[B]physicsandpsychology[C]sociologyandpsychology[D]physicsandchemistryormation)richandtheinfopoor.Andthatdividedoesexisttoday.MywifeandIlecturedaboutthisloomingdangertwen tyyearsago.Whatwaslessvisiblethen,however,werethenew,positiveforcesthatworkagainstthedigitaldivide.Therearereasonstobeoptimistic.Therearetechnologicalreasonstohopethedigitaldividewillnarrow.AstheInternetbecomesmoreandmoreco mmercialized,itisintheinterestofbusinesstouniversalizeaccess--afterall,themorepeopleonline,themorepotential customersthereare.Moreandmoregovernments,afraidtheircountrieswillbeleftbehind,wanttospreadInternetacce ss.Withinthenextdecadeortwo,onetotwobillionpeopleontheplanetwillbenettedtogether.Asaresult,Inowbelievet hedigitaldividewillnarrowratherthanwidenintheyearsahead.AndthatisverygoodnewsbecausetheInternetmayw ellbethemostpowerfultoolforcombatingworldpovertythatwe’veeverhad.Ofcourse,theuseoftheInternetisn’ttheonlywaytodefeatpoverty.AndtheInternetisnottheonlytoolwehave.Butithasenormouspotential.Totakeadvantageofthistool,someimpoverishedcountrieswillhavetogetovertheiroutdatedanti-colonialprej udiceswithrespecttoforeigninvestment.Countriesthatstillthinkforeigninvestmentisaninvasionoftheirsovereignt ymightwellstudythehistoryofinfrastructure(thebasicstructuralfoundationsofasociety)intheUnitedStates.Whent heUnitedStatesbuiltitsindustrialinfrastructure,itdidn’thavethecapitaltodoso.AndthatiswhyAmerica’sSecondW aveinfrastructure--includingroads,harbors,highways,portsandsoon--werebuiltwithforeigninvestment.TheEngl ish,theGermans,theDutchand theFrenchwereinvestinginBritain’sformercolony.Theyfinancedthem.Immigrant Americansbuiltthem.Guesswhoownsthemnow?TheAmericans.Ibelievethesamethingwouldbetrueinplaceslike Braziloranywhereelseforthatmatter.ThemoreforeigncapitalyouhavehelpingyoubuildyourThirdWaveinfrastruc ture,whichtodayisanelectronicinfrastructure,thebetteroffyou’regoingtobe.Thatdoesn’tmeanlyingdownandbec omingfooled,orlettingforeigncorporationsrununcontrolled.Butitdoesmeanrecognizinghowimportanttheycanb[A]howwell-developeditiselectronically[B]whetheritisprejudicedagainstimmigrants[C]whetheritadoptsAmerica’sindustrialpattern[D]howmuchcontrolithasoverforeigncorporationsText3WhydosomanyAmericansdistrustwhattheyreadintheirnewspapers?TheAmericanSocietyofNewspaperEd itorsistryingtoanswerthispainfulquestion.Theorganizationisdeepintoalongself-analysisknownasthejournalismcredibilityproject.Sadtosay,thisprojecthasturnedouttobemostlylow-levelfindingsaboutfactualerrorsandspellingandgramma rmistakes,combinedwithlotsofhead-scratchingpuzzlementaboutwhatintheworldthosereadersreallywant.Butthesourcesofdistrustgowaydeeper.Mostjournalistslearntoseetheworldthroughasetofstandardtemplates (patterns)intowhichtheyplugeachday’sevents.Inotherwords,thereisaconventionalstorylineinthenewsroomcultu rethatprovidesabackboneandaready-madenarrativestructureforotherwiseconfusingnews.Thereexis tsasocialandculturaldisconnectbetweenjournalistsandtheirreaders,whichhelpsexplainwhythe“s tandardtemplates”ofthenewsroomseemalientomanyreaders.Inarecentsurvey,questionnairesweresenttoreporter sinfivemiddle-sizecitiesaroundthecountry,plusonelargemetropolitanarea.Thenresidentsinthesecommunitieswerephonedatrandomandaskedthesamequestions.RepliesshowthatcomparedwithotherAmericans,journalistsaremorelikelytoliveinupscaleneighborhoods,h avemaids,ownMercedeses,andtradestocks,andthey’relesslikelytogotochurch,dovoluntee rwork,orputdownroot[D]rathersuperficial61. Thebasicproblemofjournalistsaspointedoutbythewriterliesintheir________.[A]workingattitude[B]conventionallifestyle[C]worldoutlook[D]educationalbackground62. Despiteitsefforts,thenewspaperindustrystillcannotsatisfythereadersowingtoits________.[A]failuretorealizeitsrealproblem[B]tendencytohireannoyingreporters[C]likelinesstodoinaccuratereporting[D]prejudiceinmattersofraceandgenderText4Theworldisgoingthroughthebiggestwaveofmergersandacquisitionseverwitnessed.Theprocesssweepsfro mhyperactiveAmericatoEuropeandreachestheemergingcountrieswithunsurpassedmight.Manyinthesecountrie sarelookingatthisprocessand worrying:“Won’tthewaveofbusinessconcentrationturnintoanuncontrollableanti-competitiveforce?”[A]totakeinmoreforeignfunds[B]toinvestmoreabroad[C]tocombineandbecomebigger[D]totradewithmorecountries64. Accordingtotheauthor,oneofthedrivingforcesbehindM&Awaveis________.[A]thegreatercustomerdemands[B]asurplussupplyforthemarket[C]agrowingproductivity[D]theincreaseoftheworld’swealth65. FromParagraph4wecaninferthat________.[A]theincreasingconcentrationiscertaintohurtconsumers[B]WorldComservesasagoodexampleofbothbenefitsandcosts[C]thecostsoftheglobalizationprocessareenormous[D]theStandardOilTrustmighthavethreatenedcompetition66. Towardthenewbusinesswave,thewriter’sattitudecanbesaidtobe________.[A]optimisticShe afterab uild-ipsonanythingfromrecyclingtheircling-filmtomakingtheirownsoap;thereareevensupportgroupsforthosewhowanttoachievethemid-’90sequivalentofdroppingout.WhileinAmericathetrendstartedasareactiontotheeconomicdecline--afterthemassredundanciescausedbydo wnsizinginthelate’80s--andisstilllinkedtothepoliticsofthrift,inBritain,atleastamongthemiddle-classdownshifte rsofmyacquaintance,wehavedifferentreasonsforseekingtosimplifyourlives.Forthewomenofmygenerationwhowereurgedtokeepjugglingthroughthe’80s,downshiftinginthemid-’90si snotsomuchasearchforthemythicalgoodlife--growingyourownorganicvegetables,andriskingturningintoone--asapersonalrecognitionofyourlimitations.67. WhichofthefollowingistrueaccordingtoParagraph1?[A]Full-timeemploymentisanewinternationaltrend.[B]Thewriterwascompelledbycircumstancestoleaveherjob.[C]“Alateralmove”meanssteppingoutoffull-timeemployment.[D]Thewriterwasonlytooeagertospendmoretimewithherfamily.68. Thewriter’sexperimentshowsthatdownshifting________.[A]enableshertorealizeherdream[B]helpshermoldanewphilosophyoflife[C]promptshertoabandonherhighsocialstatus[D]leadshertoacceptthedoctrineof She magazineTotalR71)Therewillbetelevisionchatshowshostedbyrobots,andcarswithpollutionmonitorsthatwilldisablethemw hentheyoffend.72)Childrenwillplaywithdollsequippedwithpersonalitychips,computerswithin-builtpersonaliti eswillberegardedasworkmatesratherthantools,relaxationwillbeinfrontofsmell-television,anddigitalagewillhavearrived.AccordingtoBT’sfuturologist,IanPearson,theseareamongthedevelopmentsscheduledforthefirstfewdecade softhenewmillennium(aperiodof1,000years),whensupercomputerswilldramaticallyaccelerateprogressinallareasoflife.73)Pearsonhaspiecedtogethertheworkofhundredsofresearchersaroundtheworldtoproduceauniquemillenn iumtechnologycalendarthatgivesthelatestdateswhenwecanexpecthundredsofkeybreakthroughsanddiscoveriest otakeplace.Someofthebiggestdevelopmentswillbeinmedicine,includinganextendedlifeexpectancyanddozensofartificialorganscomingintousebetweennowand2040.Pearsonalsopredictsabreakthroughincomputer-humanlinks.“Bylinkingdirectlytoournervoussystem,comp uterscouldpickupwhatwefeeland,hopefully,simulatefeelingtoosothatwecanstarttodevelopfullsensoryenvironm ents,ratherliketheholidaysin TotalRecall orthe StarTrek holodeck,”hesays.74)Butthat,Pearsonpointsout,isonlyth estartofman-machineintegration:“Itwillbethebeginningofthelongprocessofintegrationthatwillultimatelyleadtoafullyel ectronichumanbeforetheendofthenextcentury.”Throughhisresearch,Pearsonisabletoputdatestomostofthebreakthroughsthatcanbepredicted.However,ther earestillnoforecastsforwhenfaster-than-lighttravelwillbeavailable,orwhenhumancloningwillbeperfected,orwh entimetravelwillbepossible.Buthedoesexpectsocialproblemsasaresultoftechnologicaladvances.Aboominneigh borhoodsurveillancecameraswill,forexample,causeproblemsin2010,whilethearrivalofsyntheticlifelikerobotsw illmeanpeoplemaynotbeabletodistinguishbetweentheirhumanfriendsandthedroids.75)AndhomeapplianceswillSectionIII:ReadingComprehension(40points)SectionIV:English-ChineseTranslation(15points)71. 届时,将出现由机器人主持的电视谈话节目以及装有污染监控器的汽车,一旦这些汽车排污超标(违规),监控器就会使其停驶。
诸葛亮足智多谋在草船借箭里读智多谋英语作文全文共3篇示例,供读者参考篇1Zhuge Liang's Ingenious Strategy at the Battle of Chibi"If you know the enemy and know yourself, you need not fear the result of a hundred battles." This famous quote from the ancient Chinese military strategist Sun Tzu perfectly encapsulates the brilliance of Zhuge Liang's tactics at the pivotal Battle of Chibi in 208 AD during the Three Kingdoms period of Chinese history. Zhuge Liang, serving as the chancellor and prime strategist for the state of Shu Han, employed his unparalleled intelligence, foresight, and cunning to overcome the formidable forces of the numerically superior Cao Cao of the Wei state. Through his masterful "Borrowed Arrows" strategy, Zhuge Liang achieved an improbable victory against overwhelming odds, cementing his reputation as one of history's greatest military strategists.To understand the magnitude of Zhuge Liang's achievement, one must first appreciate the dire circumstances facing the Shu Han forces. Cao Cao had assembled a gargantuan navy of over800,000 men to conquer the Yangzi River valley and unite the fragmented Three Kingdoms under his rule. In contrast, the Shu Han forces led by the young emperor Liu Bei were vastly outnumbered, commanding a mere 50,000 troops. Outmatched on both land and water, defeat seemed all but inevitable for the Shu Han kingdom. It was under these desperate conditions that Zhuge Liang devised his audacious stratagem.At the heart of Zhuge Liang's plan was the shrewd exploitation of an easterly wind that blew across the Yangzi River every afternoon without fail. By luring Cao Cao's naval forces into a narrow section of the river, Zhuge Liang positioned his smaller fleet such that the afternoon winds would be at their back, while Cao Cao's ships would be directly facing the powerful gusts head-on. However, this was merely the setup for Zhuge Liang's true masterstroke - the "Borrowed Arrows" maneuver itself.In a daring feint, Zhuge Liang had his soldiers construct thousands of small boats and rafts laden with bales of dry wheat reed bundled tightly together. As the winds picked up in the afternoon, these unmanned fire-rafts were strategically set adrift directly towards Cao Cao's crowded naval formations. From the relatively safe rear lines, Zhuge Liang's archers then rained downa hail of flaming arrows onto the fire-rafts, igniting the dry reeds into an unstoppable conflagration.Trapped by the narrow river banks with the winds whipping the flames towards them, Cao Cao's vast armada was plunged into utter chaos and pandemonium. Ships collided and crashed into one another as terrified soldiers jumped overboard in a futile attempt to escape the hellish inferno. Those who remained aboard had no means to extinguish the flames as their ships were consumed from bow to stern. Within moments, theonce-mighty imperial fleet had dissolved into a smoldering graveyard of shattered hulls and scorched debris. Cao Cao himself barely escaped with his life.In one stunningly ingenious maneuver, Zhuge Liang had single-handedly decimated the core of Cao Cao's military might. This decisive victory not only ensured the survival of the Shu Han kingdom for years to come, but it fundamentally altered the balance of power in the Three Kingdoms period. All achieved through guile and calculated strategy rather than mere brute force. As the ancient Chinese philosopher Laozi wisely stated, "A violent wind does not last for a whole morning; a sudden rain does not last for the whole day." Zhuge Liang embodied thisethos, eschewing prolonged warfare in favor of a swift, surgical strike that played perfectly to his inherent strengths.Beyond the remarkable tactics themselves, what truly elevated Zhuge Liang's "Borrowed Arrows" stratagem was the extraordinary degree of foresight and meticulous planning behind its execution. Every contingency had been carefully calculated and prepared for well in advance. From the precise timing of the winds and river currents, to the most favorable positioning of his comparatively tiny fleet, to the construction and deployment of the fire-rafts themselves - no detail was too minute to escape Zhuge Liang's brilliant strategic mind.Indeed, it was said that even months before the battle commenced, Zhuge Liang had planted undercover agents among Cao Cao's ranks to monitor his troop movements and logistical preparations. When news reached him that Cao Cao was relentlessly consuming every last pound of hay and kindling from the surrounding countryside to feed his gargantuan army, Zhuge Liang deduced their eventual route would be along the Yangzi River where he could spring his watery ambush.Such an astonishing level of perspicacity and advanced strategic calculation was unheard of in Zhuge Liang's era - and even by modern standards he exhibited a level of operationalgenius rivaling history's most legendary battlefield commanders. Litt le wonder then, that his reputation as the Cìvilized or Crouching Dragon endured for centuries after his passing. Like the famous Chinese dragon of myth, Zhuge Liang's true power lay patiently coiled, awaiting the opportune moment to strike with devastating force.In the final analysis, the Battle of Chibi and the fabled "Borrowed Arrows" strategy will be forever remembered as Zhuge Liang's masterpiece - an intricate byoscence of unrivaled military genius and masterful tactics. More than just a battlefield victory, it served as a testament to the power of the human intellect, illustrating how a singularly brilliant strategist can tame the chaos of war through careful study, preparation, and execution. For in Zhuge Liang's own words, "Foreknowledge cannot be gotten from ghosts and spirits, cannot be had by analogy, cannot be found growing in the ground. It must be grubbed for in the very marrow of reality."篇2Zhuge Liang's Brilliant Stratagem in The Borrowing of Arrows with Thatched BoatsZhuge Liang, the brilliant strategist who served under the warlord Liu Bei during the Three Kingdoms period of ancient China, is renowned for his exceptional military tactics and ingenious strategies. Among his numerous achievements, one particular stratagem stands out as a testament to his unparalleled wit and resourcefulness – the borrowing of arrows with thatched boats.This legendary event took place during the Battle of Chibi in 208 AD, a pivotal conflict that pitted the allied forces of Liu Bei and Sun Quan against the formidable army of Cao Cao. Outnumbered and outmaneuvered, Zhuge Liang devised an audacious plan that would turn the tide of battle and etch his name into the annals of military history.The backdrop was set in the treacherous waters of the Yangtze River, where Cao Cao's vast navy lay anchored, poised to crush the allied forces. Recognizing the impending danger, Zhuge Liang concocted a stratagem so cunning and unconventional that it defied all conventional wisdom.With a keen eye for detail and an unwavering determination, Zhuge Liang ordered the construction of several ingenious thatched boats. These vessels, crafted from woven reeds and straw, appeared unassuming and harmless on the surface.However, their true purpose was far more devious and calculated.Zhuge Liang's plan hinged on a crucial element – the scarcity of arrows. Aware that Cao Cao's forces possessed a limited supply of arrows, he devised a way to deplete their reserves through sheer deception. The thatched boats were loaded with straw bundles, carefully arranged to resemble troops and fortifications.As the allied forces maneuvered their fleet near Cao Cao's navy, Zhuge Liang orchestrated a theatrical display. The thatched boats were set adrift, drifting aimlessly towards the enemy ships. Cao Cao's soldiers, believing these vessels to be enemy reinforcements, unleashed a relentless barrage of arrows, peppering the straw-filled boats with countless volleys.With each arrow embedded in the straw, Cao Cao's reserves dwindled rapidly, and his forces were unwittingly disarmed. Zhuge Liang's stratagem had succeeded beyond measure, leaving Cao Cao's navy severely compromised and vulnerable.The true genius of Zhuge Liang's plan lay not only in its audacity but also in its psychological impact. By exploiting the enemy's fear and creating an illusion of impending danger, he manipulated Cao Cao's forces into squandering their preciousresources. This brilliant display of psychological warfare demonstrated Zhuge Liang's profound understanding of human nature and his ability to exploit it to his advantage.The aftermath of this stratagem was nothing short of remarkable. Cao Cao's once-formidable navy, stripped of its arrows and deprived of its offensive capabilities, found itself at the mercy of the allied forces. The Battle of Chibi culminated in a resounding victory for Liu Bei and Sun Quan, thanks to the ingenuity and foresight of Zhuge Liang.Throughout history, military strategists have studied and marveled at the borrowing of arrows with thatched boats, hailing it as a masterpiece of deception and psychological warfare. Zhuge Liang's stratagem exemplified the art of outwitting an enemy without engaging in direct combat, a testament to his strategic brilliance and his ability to think outside the conventional boundaries of warfare.Moreover, this event highlights the importance of resourcefulness and adaptability in military strategy. By leveraging humble materials and unconventional tactics, Zhuge Liang demonstrated that truegenius lies not in brute force but in the ability to exploit opportunities and turn perceived weaknesses into strengths.The legacy of Zhuge Liang's stratagem extends far beyond the battlefield, serving as a timeless reminder of the power of intellect, creativity, and psychological warfare. His ability to outsmart his opponents through cunning and deception has inspired generations of strategists, leaders, and thinkers, transcending the realms of military strategy and permeating various aspects of human endeavor.In an era where warfare was often characterized by brute force and sheer numbers, Zhuge Liang's borrowing of arrows with thatched boats stood as a shining example of the triumph of wit over might. It showcased the profound impact that a single brilliant mind could have on the course of history, and cemented Zhuge Liang's reputation as one of the greatest strategists the world has ever known.As students of history, we are compelled to study and admire the ingenuity and resourcefulness displayed by Zhuge Liang in this legendary stratagem. It serves as a powerful reminder that true greatness often lies in the ability to think creatively, adapt to circumstances, and outsmart adversaries through unconventional means. By embracing the principles exemplified in the borrowing of arrows with thatched boats, wecan cultivate the skills necessary to navigate complex challenges and emerge victorious, even in the face of overwhelming odds.In conclusion, Zhuge Liang's borrowing of arrows with thatched boats stands as a testament to the power of intellect, strategy, and psychological warfare. This legendary stratagem not only secured a decisive victory for the allied forces but also etched Zhuge Liang's name into the annals of military history as a brilliant strategist and mastermind. Its legacy continues to inspire and captivate individuals across disciplines, serving as a timeless reminder of the transformative potential of innovative thinking and resourcefulness.篇3Zhuge Liang's Resourceful Strategy: Borrowed Arrows with Thatched BoatsThe era of the Three Kingdoms in ancient China was a tumultuous time marked by constant warfare and power struggles between rival warlords. Amidst the chaos, there emerged a brilliant military strategist named Zhuge Liang, whose cunning tactics and foresight earned him a legendary reputation. One of the most renowned examples of his strategic genius is the "Borrowed Arrows with Thatched Boats" story, whichshowcases his ability to turn seemingly disadvantageous situations into decisive victories.The story takes place during the conflict between the kingdoms of Shu Han and Wei, with Zhuge Liang leading the Shu Han forces. As they approached the heavily fortified Dingjun Mountain, controlled by the Wei army, Zhuge Liang found himself facing a formidable obstacle. The narrow mountain pass was guarded by a strong enemy force, and a direct assault would have been suicidal. However, Zhuge Liang's brilliant mind had already devised an ingenious plan to overcome this challenge.Zhuge Liang ordered his soldiers to construct a vast number of small boats made from thatched reeds and straw. These lightweight vessels were then equipped with straw dummies and arrows, creating the illusion of a massive naval force approaching from the river. Simultaneously, he dispatched a small contingent of soldiers to march towards the mountain pass, carrying minimal supplies and appearing ill-equipped for battle.As the Wei commanders observed this peculiar sight, they were baffled by Zhuge Liang's unconventional tactics. The thatched boats, adorned with straw dummies and arrows, seemed to be a formidable naval force, while the meager land troops appeared to be a decoy or a scouting party. Faced withthis perplexing situation, the Wei commanders made a fateful decision – they focused their defenses on the perceived naval threat, diverting troops and resources away from the mountain pass.Seizing this opportunity, Zhuge Liang's land troops swiftly advanced through the lightly guarded mountain pass, catching the Wei forces off guard. With the element of surprise on their side, the Shu Han army emerged victorious, securing a crucial foothold in the region.The true brilliance of Zhuge Liang's strategy lies in his ability to exploit the psychological vulnerabilities of his opponents. By creating an illusion of a massive naval force, he compelled the Wei commanders to allocate their resources inefficiently, leaving their defenses vulnerable to his true objective – capturing the mountain pass.Zhuge Liang's masterful use of deception and misdirection is a testament to his profound understanding of military strategy and human psychology. He recognized that victory is not always achieved through sheer force but through the intelligent manipulation of perceptions and expectations.Moreover, the "Borrowed Arrows with Thatched Boats" strategy highlights Zhuge Liang's resourcefulness andadaptability. With limited resources at his disposal, he ingeniously repurposed seemingly ordinary materials like straw and reeds to create a convincing ruse. This ability to think outside the box and leverage unconventional methods was a hallmark of his strategic prowess.Beyond its military significance, the story also reflects the broader philosophical principles that guided Zhuge Liang's approach to warfare. He believed in achieving victory through minimal bloodshed and avoiding unnecessary sacrifices. By employing deception and psychological tactics, he sought to outmaneuver his opponents without resorting to full-scale confrontation, thereby minimizing casualties on both sides.Furthermore, Zhuge Liang's strategy exemplifies the importance of adaptability and situational awareness in military operations. He recognized that rigid adherence to conventional tactics could often lead to stalemates or costly failures. Instead, he embraced flexibility and tailored his strategies to the specific circumstances, exploiting weaknesses in the enemy's defenses and capitalizing on unexpected opportunities.The legacy of Zhuge Liang's "Borrowed Arrows with Thatched Boats" strategy has endured for centuries, inspiring generations of military strategists and leaders across cultures. Itsprinciples of deception, psychological warfare, and resourcefulness have been studied and emulated in various conflicts throughout history.In contemporary times, the lessons from this legendary strategy remain relevant, transcending the realm of military operations. The ability to think creatively, leverage limited resources, and outmaneuver opponents through unconventional tactics holds value in diverse fields, from business and politics to social movements and conflict resolution.Zhuge Liang's masterful strategy serves as a reminder that true strategic excellence lies not only in raw strength or resources but in the ability to outsmart and outmaneuver adversaries through ingenuity, adaptability, and psychological insights. His legacy continues to inspire leaders and strategists to embrace innovative thinking, challenge conventional wisdom, and seize opportunities where others see only obstacles.In conclusion, the "Borrowed Arrows with Thatched Boats" story stands as a testament to Zhuge Liang's exceptional strategic acumen and his ability to turn seemingly disadvantageous situations into decisive victories. Through his masterful use of deception, psychological warfare, and resourcefulness, he secured a remarkable triumph that hasetched his name in the annals of military history. As we study and appreciate this legendary strategy, we are reminded of the enduring power of human ingenuity and the importance of embracing unconventional thinking in the face of formidable challenges.。
a r X i v :g r -q c /0107092v 5 25 F eb 2003Conventional Forces can Explain the Anomalous Acceleration of Pioneer 10Louis K.Scheffer ∗Cadence Design Systems 555River Oaks Parkway San Jose,CA 95134(Dated:February 7,2008)Anderson,et al.find the measured trajectories of Pioneer 10and 11spacecraft deviate from the trajectories computed from known forces acting on them.This unmodelled acceleration (and the less well known,but similar,unmodelled torque)can be accounted for by non-isotropic radiation of spacecraft heat.Various forms of non-isotropic radiation were proposed by Katz,Murphy,and Scheffer,but Anderson,et al.felt that none of these could explain the observed effect.This paper calculates the known effects in more detail and considers new sources of radiation,all based on spacecraft construction.These effects are then modelled over the duration of the experiment.The model reproduces the acceleration from its appearance at a heliocentric distance of 5AU to the last measurement at 71AU to within 10percent.However,it predicts a larger decrease in acceleration between intervals I and III of the Pioneer 10observations than is observed.This is a 2sigma discrepancy from the average of the three analyses (SIGMA,CHASMP,and Markwardt).A more complex (but more speculative)model provides a somewhat better fit.Radiation forces can also plausibly explain the previously unmodelled torques,including the spindown of Pioneer 10that is directly proportional to spacecraft bus heat,and the slow but constant spin-up of Pioneer 11.In any case,by accounting for the bulk of the acceleration,the proposed mechanism makes it much more likely that the entire effect can be explained without the need for new physics.PACS numbers:04.80.-y,95.10.Eg,95.55.PeI.INTRODUCTIONIn [1],Anderson et pare the measured trajec-tory of spacecraft against the theoretical trajectory com-puted from known forces acting on the spacecraft.They find a small but significant discrepancy,referred to as the unmodelled or anomalous acceleration.It has an approximate magnitude of 8×10−8cm s −2directed approximately towards the Sun.Needless to say,any acceleration of any object that cannot be explained by conventional physics is of considerable interest.These spacecraft have been tracked very accurately over a pe-riod of many years,so the data are quite reliable,and the analysis,though complex,has been reproduced by Markwardt[2].Explanations for the acceleration fall into two general categories -either new physics is needed or some conventional force has been overlooked.One of the most likely candidates for the anomalous acceleration is non-isotropic radiation of spacecraft heat.This is an appealing explanation since the spacecraft dis-sipates about 2000watts total;if only 58watts of this to-tal power was directed away from the sun it could account for the acceleration.The bulk of the spacecraft heat is radiated from the two Radioisotope Thermoelectric Gen-erators (RTGs),which convert the heat of decaying plu-tonium to electrical power to run the spacecraft.The remainder of the heat is radiated from various spacecraft components as a result of electrical power dissipation,and by a few small Radioisotope Heater Units (RHUs)2than the observed acceleration.The discrepancy is small (less than 1σ)from the analysis of Markwardt[2],but roughly a 2σdiscrepancy from the average results of the three analyses.Getting radiation forces right is notoriously difficult.Even for Cassini,whose construction is well known,the predicted and measured values differ by 50%[3].How-ever,the total force can be no larger than the sum of the possible components,though it can easily be less.Therefore the main job is to show that enough force is available;any lesser result is easily explained.II.THE ANOMALOUS ACCELERATIONAs the Pioneer spacecraft recede from the sun,solar forces decrease and only gravitational forces,and an oc-casional maneuver,should affect the trajectory of the spacecraft.Anderson,et al.noticed that a small ad-ditional acceleration needed to be added to make the measured data and computations match.This is the anomalous acceleration,which started to become notice-able about 5AU from the sun.It was roughly the same for Pioneer 10and 11,as shown in Figure1.FIG.1:Unmodelled acceleration as a function of distance from the sun,by Anderson et al.[3].Additional constraints come from further study of Pi-oneer 10,since the data are higher quality and the data span is long enough to provide significant constraints due to the radioactive decay of the heat sources.Figure 2,re-produced from [4],shows the measured acceleration 1987to 1998.(Although they have different horizontal axes,Figure 2largely follows Figure 1chronologically.Pio-neer 10was at 40AU in 1987.)The authors divide the history into three intervals.Interval I is January 1987to July of 1990,interval II from July of 1990to July of 1992,and interval III is from July of 1992to the June of 1998.The authors make this distinction by looking at the spin rate of the craft (see Figure 3).In intervals I and III it was decreasing smoothly,but in interval II it decreased quickly and irregularly.They therefore consider the data from interval II to be less reliable than intervals I and III,since whatever affected the spin in interval II (probably gas leaks)may also have affected theacceleration.FIG.2:Unmodelled acceleration and an empirical fit from Turyshev[4].More recent analyses have refined these results some-what,though the main conclusions remain unchanged.Three different analyses have been reported in the litera-ture.SIGMA and CHASMP are two different trajectory modelling programs each with many possible analysis op-tions.We use the best Weighed Least Squares (WLS)results from each program,from [3].Markwardt[2]wrote an new program with the explicit goal of an independent re-analysis.Table I shows the most recent results from [3],which fits a constant,independent acceleration in each inter-val.Table II shows the results of Markwardt’s re-analysis which fits a constant plus a linear term to the data from 1987-1994.His best solution isa (t )=−8.13·10−8cm /sec 2+3.7·10−17t cm /sec 3where t is the time in seconds since the beginning of 1987.Accelerations are in units of 10−8cm s −2.For convenience,we show the amount of directed power,in watts,that would be needed to account for each acceler-ation,assuming the 241kg estimate of spacecraft mass from [3].Note that each program claims very small formal er-rors,but the programs differ from each other by far greater amounts.Therefore the errors are probably sys-TABLE I:Summary of results from Anderson,et al.[3] Interval SIGMA equivaccel.watts Jan87-Jul908.00±0.0159.656.77.91±0.01equiv.accel.55.7(all data,constant acc.)Jan87-Jul907.98±0.0258.8(from linearfit)Jan87-Jul907.93±0.0251.6(extrapolated from linearfit)FIG.5:Reproduction of Figure3.1-2from[5].A few lines were removed for clarity,and the main equipment compart-ment is shaded in.and internally-mounted sensors are in an instrument bay (“squashed”hexagon)mounted on one side of the central hexagon.At present only about65W of power is available to Pi-oneer10[8].Therefore,all the instruments are no longer able to operate simultaneously.But the power subsystem continues to provide sufficient power to support the cur-rent spacecraft load:transmitter,receiver,command and data handling,and the Geiger Tube Telescope(GTT)sci-ence instrument.The sunward side of the spacecraft is the back,and the anti-sunward side,in the direction of motion,is the front[9].B.Gas leaksGas leaks are always a prime suspect when unmodelled spacecraft accelerations are found.As the authors them-selves say“Although this effect is largely unpredictable, many spacecraft have experienced gas leaks producing accelerations on the order of10−7cm/s2”[3].Further-more the authors think that gas leaks are a significant part of the spin behavior.Why then do they think that gas leaks are not the source of the acceleration?They present four arguments:•The effect seems constant over long periods of time(many years).•The acceleration does not change as a result ofthruster activity,as many gas leaks do(as valvesseat/unseat.)•The effect is roughly the same on two spacecraft,Pioneer10and11.•A force big enough to cause the acceleration wouldcause bigger spin changes than are observed unlessit was directed along the spin axis.In rebuttal,there are many possible sources of gas leaks, not all of which are variable or affected by thruster ac-tivity.(The same authors[3]speculate that a gas leak causes the spin-up of Pioneer11,which is also constant and unaffected by maneuvers through4years.)Further-more,the two spacecraft were intended to be identical,so an identical artifact such as a gas leak would not be sur-prising,and it might be aligned with the axis.In short, it would require an unusual gas leak,duplicated on each spacecraft,to cause the observed effect,but it is certainly allowed by physics.In[3],the error budget for gas leaks is set as follows: First,take the biggest uncommanded spin-rate change, assume it was caused by gas leaks,assume the leak was at the spin thrusters,and then increase it a little.Thus they are setting the budget to the biggest known leak on this particular spacecraft.This is hardly a rigorous method for estimating the maximum possible size of an unknown leak,since there could be more than one leak, and locations other than the thrusters require a bigger leak for the same spin change.Furthermore,as the au-thors note,other spacecraft are known to have had larger leaks.Clearly at least some of the authors of[3]are not convinced by their own argument since they still suspect gas leaks as the cause of the unmodelled acceleration([3], Section XII).C.Non-isotropic radiation-previous work Murphy suggests that the anomalous acceleration seen in the Pioneer10/11spacecraft can be,“explained, at least in part,by non-isotropic radiative cooling of the spacecraft.”[10],The main idea is that heat from the main and instrument compartments would radiate through the cooling louvers on the front of the craft.An-derson,et al.argue in reply[11]that over the data span in question the louver doors were already closed(if the doors were open then the effect would surely be signif-icant).They conclude“the contribution of the thermal radiation to the Pioneer anomalous acceleration should be small.”They also argue that the spacecraft power is decreasing,but the unmodelled acceleration is not.5Scheffer[12]points out that the front of the spacecraft has a much higher emissivity than typical thermal blan-kets(even with the louvers closed),and therefore the majority of the heat will radiate from the front in any case.Anderson,et al.[13]dispute this,based on the emissivity data in[5],which assigns a high emissivity to the thermal blanket.(This data is true but misleading-it specifies the emissivity of the outer layer of the blanket. This is very different from the emissivity of the blanket as a whole,called the effective emissivity,which is quite low.The next section has a more in-depth discussion of this point.)Katz[14]proposes that at least part of the acceleration is generated by radiation from the RTGs reflecting offthe back of the antenna.Anderson et al.in[15]argue that this effect must be small since the antenna is end-on to the RTGs,and hence gets very little illumination. Slusher(as credited by Anderson)proposed that the forward and backward surfaces of the RTGs may emit non-equally.Anderson et al.conclude there is no credible mechanism to explain the large difference in surfaces that would be required if this was to explain the whole effect.IV.DISCUSSIONWe consider asymmetrical radiation from5sources-the RTGs themselves,the two spacecraft compartments, RTG radiation reflected from the antenna,the Radioiso-tope Heater Units(RHUs)on the spacecraft,and radi-ation from the feed that misses the antenna.We also consider one modelling error,a mis-estimation of the re-flectivity of the antenna to solar radiation.Consider thermal radiation from the spacecraft body with the louvers closed,as they have been since9AU. An extremely simple argument shows that the electri-cal power dissipated in the main spacecraft compartment must result in a significant amount of thrust.The Pi-oneer antenna points roughly at the sun,and the in-strument compartment is directly behind the antenna. Since the antenna blocks radiation in the sunward di-rection,the waste heat must be preferentially rejected anti-sunward.Referring to Figure5,a good scale model is a60watt bulb about4cm behind a25cm diameter pie dish.The dish casts a huge shadow in the sunward direction,resulting in an average anti-sunward thrust. However,the efficiency of conversion of heat to thrust is higher than this simple argument indicates.From[5],“The Pioneer F/G thermal control concept consists of an insulated equipment compartment with passively con-trolled heat rejection via an aft[25]mounted louver sys-tem.”Since even a closed louver is a much better radia-tor than thermal insulation,most of the radiation occurs from the front.It’s as simple as that!Instrument heat may also contribute to thrust,but possibly with less efficiency.This is because the instru-ments could possibly radiate at right angles to the spin axis through their observation ports,which are not cov-ered with thermal blankets.Furthermore,the science compartment is much closer to the edge of the dish than the main compartment,so the dish will shadow much less of any thermal radiation generated by the science instruments.We estimate the efficiency using the spacecraft con-struction.Assuming a uniform internal temperature,the power emitted from each surface is proportional to the area times the effective emissivity of the surface.The front and back of the central equipment compartment have about1.3m2area,and the sides about1.5m2to-tal.The sides and the rear of the compartment are cov-ered with multi-layer insulation(MLI)[5].When calcu-lating radiation from multi-layer insulation,the correct value to use is the“effective”emissivity,ǫeff,which ac-counts for the lower temperature of the outer layer[16]. (Anderson[13]points out that the outer layer of the MLI has an emissivity of0.70according to[5].This is not a contradiction because the outer layer of the MLI is much colder than the interior-that’s how MLI works.) From[16],the multilayer insulation from on Pioneer10 has an effective emissivity of0.007to0.01(see Figure 6).Assuming a value of0.0085,and a1998internal tem-perature of241K[17],the main compartment will lose about4watts total through the MLI on the sides and back(Even this may be an over-estimate.Two of the sides are facing1Kw IR sources just2meters away,and may even conduct heat into the compartment.).Allow-ing a few watts for conduction losses through wires and struts,perhaps10%of the power(about6watts)goes through the back,10%through the sides,and the remain-ing80%through the front.The back radiation will have a near zero efficiency(it squirts out from between the dish and the compartment at right angles to theflight path). Radiation from the side should be about10%efficient, assuming Lambertian radiation and a45degree obstruc-tion by the dish.Radiation from the front will be about 66%efficient,again assuming Lambertian emission.The overall efficiency of main bus radiation could therefore be as high as54%.Is it reasonable for the front of the main compartment to radiate the47watts or so this requires?At an aver-age temperature of241K,and assuming aflat surface, this would require an average emissivity of0.19.From a picture of the Pioneer10replica in the National Air and Space Museum[18],the front of the spacecraft is rather complex,with considerable surface area(such as a rather large cylinder that connects to the booster)and a variety of surfacefinishes.There are also some fairly large instru-ments on the front of the spacecraft,such as the plasma analyzer[5].Although the louver blades themselves have a low emissivity of0.04[5],a composite emissivity of0.19 seems reasonable.The main conclusion seems quite robust.Multi-layer insulation is specifically designed to reduce heat losses, whereas the louvers have at most one layer of obstruction even when closed,and by definition are riddled with dis-continuities,which are a major source of heat leaks[16].6FIG.6:Figure from[16].Pioneer F became Pioneer10.The lowest emissivity material on the front,0.04,has atleast4times the highest quoted emissivity of the sidesand back.Surely,therefore,a majority of the heat willbe radiated from the front of the spacecraft.A.Feed pattern of the radio beamAn ideal radio feed antenna would illuminate its dishuniformly,with no wasted energy missing the dish.How-ever,the feed is physically small and cannot create such asharp edged distribution,so some radiation always spillsover the edge.Since dish area is wasted if not fully il-luminated,an optimum feed(for transmission)normallyallows about10%of the total power to miss the dish.This power is converted to sunward thrust with an effi-ciency of0.7since it is directed roughly45degree angleto the spin axis.The rest of the energy hits the antennaand is reflected sunward.IfǫF EED is the fraction of theenergy that misses the antenna,and the transmitter is8watts,then the net thrust towards the sun is(8w)(ǫFEED·0.7−(1−ǫFEED))This is negative as expected,since most of the radiationis sunward.As a side note,the radio beam is circularly polarizedand thus carries angular momentum away from the space-craft.A circularly polarized beam of power P and wave-lengthλwill impart a torque T ofλT=P7to3%is certainly plausible in the absence of additional data.Asymmetrical RTG radiation(to one side,not fore and aft)could also be the cause of the slow but constant spin-up observed on Pioneer11.This would explain why the spin-up is almost constant in value and unaffected by manuevers.D.Revisiting RTG reflectionSome of the waste heat from the RTGs will reflect from the back of the high gain antenna and be converted to thrust,as proposed by Katz[14].Anderson et al.[15]ar-gue that at most30watts of radiation hit the antenna, and hence RTG reflection cannot account for the whole acceleration,which is true.Similarly,Slabinski[21],in an unpublished analysis from1998,concluded that roughly 28watts of radiation hits the antenna,and hence the whole effect could not be explained.However,it is clear the effect is real,and can provide a significant fraction of the observed anomaly.Only the exact amount is in question.The RTGs are not on-axis as viewed from the antenna. From Figure5,we see that the centerline of the RTGs is behind the center of the antenna.Measurements from this diagram indicate this distance is about23.8cm. (Slabinski[21]independently estimated26cm for this dis-tance.)Anotherfigure(not included here)from[5]shows the far end of the RTGs is120.5inches(or3.06meters) from the centerline.The near end of the RTGs will then be about60cm further in,or at about2.46meters from the center.The antenna extends1.37meters from the center,so the rim of the antenna is69.8cm offaxis and 1.09meters away radially.Thus the edge of the antenna, where the illumination is by far the brightest,views the inner RTG at an32.6degree angle.This is far from on-axis.Thefins of the RTGs radiate symmetrically,and all are visible from the antenna,so the center of this illumina-tion will be23.8cm behind the antenna.The cylindrical center of the RTG is about8.4cm in radius[22]so this illumination will come from at about15.4cm behind the antenna.Thefins have more area than the cylinder,so for this calculation we take a rough weighted average and assume a cylindrical Lambertian source20cm behind the antenna.We assume the inner RTG is centered2.66me-ters from the center,and the outer RTG2.91meters. The area blocked by the antennas is shown in Figure 7in spherical coordinates.Numerical integration of the two areas shows about12watts for the near RTG and 8watts for the far one if the total RTG power is2000 watts.This does not include radiation from the endcaps or supporting rods.Combining the analyses,we conclude that at least20 watts,but no more than30watts,of radiation hits the antenna.In this paper,we will use25watts as the basis for further analysis.This energy is turned into thrustby FIG.7:Antenna size in spherical coordinates from RTGs. Radial axis is angle from the centerline in radians;other axis is angle around this line with the magnetometer defined as zero.two effects.First,the antenna shadows radiation which would otherwise go forward.An angle in the middle of the antenna is about17degrees forward;this corre-sponds to an efficiency of0.3(the true efficiency is prob-ably higher since the edge is both at a greater angle and more brightly illuminated.)Next,the energy that hits the antenna must go somewhere.Some will be absorbed and re-radiated;some will bounce into space,and some will bounce and hit the instrument compartment,and be reflected or re-radiated from there.A detailed account-ing seems difficult,but an overall efficiency of0.6to0.9 seems reasonable(0.3for shadowing and0.3to0.6for reflection and re-emission).E.Total of all effectsHere we sum the maximum value of all the effects as of1998.The total is more than enough to account for the acceleration,giving us the freedom to reduce some of the efficiencies if needed tofit the data.TABLE III:Available thrust from different sources as of1998 Source of effect Effic.Decay Rad from RHUs0.50.78%/year257.5Antenna radiate0.60.68%/year200018Feed pattern0.70%7.2-7.2Rad.,main bus0.54see text10.1Total8F.Antenna solar reflectivityIn this section we argue that a mismodelled solar reflec-tion might account for the sudden onset of the anomalousforce shown infigure1.This argument is offered only asa possible explanation of the onset and initial decrease ofthe anomalous acceleration;it is not relevant to the ex-istence,magnitude,or source of the acceleration at latertimes since past about30AU the contribution from thesolar radiation is negligable.First,we show there is surely a possibility of error inthese coefficients since the numbers for the two space-craft disagree.We start with the data from Anderson,averaging the SIGMA and CHASMP values.We assume,following Anderson(section VII-B),that the trajectorywasfit correctly but the mass used in the calculationwas incorrect.We correct thefitted values using the bestavailable estimates for spacecraft mass,keeping the ac-celeration(and hence trajectory)the same.We wouldTABLE IV:Solar reflectivity from Anderson,et al.[3]Spacecraftfitted K resultingtrue KPioneer10 1.73 1.66239.72329TABLE V:Instrument power1987-2001.IPP=Imaging Pho-topolarimeter,TRD=Trapped Radiation Detector,PA= Plasma AnalyzerDates NotesJan87-Oct93IPP offOct938.1Nov93-Sep95PA offSep950.8c·m[ǫRHU·RHU(d)+ǫRT G·RT G(d)+(8w)(ǫFEED·0.7−(1−ǫFEED))+ǫINST·INST(d)+ǫBUS·BUS(d)−K SOLAR∗SOLAR(d)]To examine thefit,we use the plots from[3,4],and try tofit them with our model.We make threefits.Thefirst is a conservativefit,using only known and documented spacecraft characteristics.The second is the nominalfit, adding in effects such as RTG asymmetry that are plau-sible but not proven.The third is constructed to get the best possiblefit to the data,but might be physically unrealistic.The conservativefit uses only known and documented spacecraft characteristics.These are that the front of the spacecraft is a better radiator than the sides[5,16],and that the antenna will block and reflect some of the RTG radiation[3,5,14,21].A goodfit is obtained with •ǫRT G=0.01.25watts hit the antenna,30%block-age efficiency,and50%reflection efficiency.•ǫINST=0.51.Instruments same as main bus forsimplicity.•ǫBUS=0.51.About80%the main bus heat goesout the front,with Lambertian efficiency.This model correctly predicts58.6watts in interval I, but predicts a decrease in interval III to48.6watts.This is a17%decrease as opposed to the3%measured in Anderson and10.6%of Markwardt.This model does not explain the onset at5AU,and overpredicts the rate of decrease,but it shows that at most20%of the effect can be due to new physics.At the very least,80%of the effect can be accounted for by entirely conventional physics, based on known,documented,and measured spacecraft construction.The nominalfit adds radiation from the RHUs,asym-metrical radiation from the RTGs,feed spillover,and so-lar reflectance mis-modelling.These sources are all plau-sible but neither proven or disproven by any records or measurements found so far.Thefit assigns the same ef-ficiency to main compartment heat and instrument heat. This avoids much of the need to look at spacecraft con-struction details and instrument history,since the accel-eration only depends on the total electrical power.The additional sources allow a betterfit since RHU and RTG heat decays more slowly than electrical heat,feed spillover does not decay at all,and we can now model the onset of the anomalous acceleration at5AU.Once again,many parameter choices give similar results.We get a reasonablefit over the entire data span with the following coefficients:•ǫRHU=0.5,the RHUs radiate like point sourcesbehind the antenna.•ǫRT G=0.016.0.3%RTG asymmetry,30%block-age efficiency,and50%reflection efficiency.•ǫF EED=0.1.10%of the feed power misses theantenna•ǫINST=0.39.Instrument heat radiates as mainbus heat for simplicity.•ǫBUS=0.39.About60%of the main bus heat goesout the front,with Lambertian efficiency.•K SOLAR=0.2.Antenna reflection estimates aretoo low by0.2.Thefit to the data is shown in Figures8and9.The agreement seems reasonable in both regimes.In partic-ular,the early anomalous acceleration between15and 40AU isfit well by this model.In Figure8two other models are shown,all assuming that a1/r2error of some sort(here solar constant mismodelling)is responsible for the onset.The middle trace assumes the acceleration is a pure exponential with an88year half life.This is the form for a model that assumes RTG radiation(direct or reflected)is asymmetric but spacecraft electrical heat is radiated isotropically.Between15and40AU this model underpredicts the observed decrease,where the nominal modelfits much better.This strongly favors a model where radiation from the spacecraft bus is a major con-tributor to the anomalous acceleration.The lower trace is a constant acceleration plus an error that scales as 1/r2.This shows that if the acceleration is indeed con-stant at large distances,a different explanation for the onset is required.Thefit from1987to1998,shown in Figure9,also looks reasonable.We compare this model to the consen-sus of the most recent analyses[3][2].Using the param-eters above,the average sunward thrust is58.0watts in interval I,and50.2watts in interval III.We can adjust the the parameters to get the correct overall average,or10FIG.9:Figure from[4],withfitted data added.The dotted line is Turyshev’s empiricalfit;the solid line is the model hypothesized in this paper.the right acceleration in interval I,but in either case we would expect to see a13.2%decrease from interval I to III,where only a5.6%decrease is observed.The7.6% discrepancy is about2standard deviations out.Taken at face value,this makes it unlikely at about the2% level that this hypothesis alone accounts for all the mea-sured result.However,the re-analysis by Markwardt[2] has concluded that the data does not rule out a slowly decreasing force,at least if the the decrease is an ex-ponential with a half life of more than50years.(This corresponds to a9%decrease in the6.75year span be-tween the midpoints of intervals I and III).The decrease here is not strictly exponential,but is close in in size andallowed by Markwardt.an even betterfit to the accelera-by assigning different efficien-and main compartment heat.Forthe RHUs radiate like point sources0.3%RTG asymmetry,30%and60%reflection efficiency.10%of the feed power misses theAbout half the main bus heat radi-with Lambertian efficiency.Instruments radiate mostly to the.2.Antenna reflection estimates are.only a4.9%discrepancy(10.5%measured)on the I-III decline andfit at earlier times.This is onlydeviations from the consensus model,fit for Markwardt.However,fig-reasonable difference between instru-and main compartment efficiency isone hand the two compartmentsbay is closer to the edge ofhas has side facing ports that extendblankets.On the other hand the twoand conductively coupled.detailed analysis it’s very hard toplausible difference in efficien-radiation offers a parsimonious ex-the anomalous acceleration and theAnderson et al.note that the Pioneeris almost perfectly correlated withRadiation from the front of theexplains this.The needed emis-plausible-in1986,there were97watts available,and13w-meters of torque mea-sured.Assuming the radiation is emitted50cm from the axis(the louver location),if the radiation was canted at an average angle of15.5degrees from the normal to the surface,it could provide the observed torque.Such an angle would decrease the conversion of power into thrust by only4%,leaving that argument intact.The louvers, covering the front surface and all canted to one side when closed,provide a natural explanation for the asymme-try required.One obvious objection to this explanation is that it predicts Pioneer11should be spinning down as well,instead of the spin-up that is actually observed. This is not a serious problem since the unknown spin-up mechanism,possibly gas leaks or RTG asymmetry,can easily overpower the small torque induced by main bus radiation.In any case,the proposed explanation,by accounting for the bulk of the effect,makes it more likely that con-。