Atmosphere-like turbulence generation with surface-etched phase-screens

学校代码10699分类号V211密级学号036050167硕士学位论文（学位研究生）题目三维N-S方程数值求解及S-A湍流模型应用研究作者李 广 宁学科、专业流体力学指 导 教 师 李 杰申请学位日期二零零六年三月摘要通过数值求解Euler方程模拟真实流场的流动特性，已经越来越不能满足现代飞机的设计要求和需要，为了更加准确地模拟流场信息，提供详细、高效、实用的气动数据，Navier-Stokes(N-S)方程组的数值求解技术已经成为计算流体力学学科的一个重要研究方向。

另外，在自然界和科学与工程实践中存在的流动现象大多数是湍流现象，我们在讨论复杂流动现象的数值模拟时，自然也就离不开对湍流现象的研究与模拟。

本文基于中心有限体积方法，采用显式四步Runge-Kutta时间推进格式进行N-S方程组的数值求解，选用一方程Spalart-Allmaras湍流模型对粘性流场进行数值模拟，并与代数Baldwin-Lomax湍流模型的粘性流场数值模拟能力进行对比研究。

本文主要进行了以下几个方面的工作：1.粘性网格生成技术。

采用沿物面边界法向外推法和求解椭圆型偏微分方程法相结合的方法生成粘性计算网格。

法向外推方法生成的内层代数网格能够保证在物面附近的网格具有很好的正交性，并可控制第一层网格至物面距离；采用Hilgenstock源项控制方法实现外层椭圆网格对边界正交性和距离的双重控制，保证了网格合理光滑的分布并具有较高的质量。

2.N-S方程组的数值求解方法研究。

对流项的空间离散采用改进的“中心有限体积+人工粘性”格式。

对人工粘性中的压力感测因子进行改进，使其具有类TVD性质，并有效地抑制不真实的数值振荡，以适应较高马赫数的流场计算，使格式更具鲁棒性。

时间推进格式采用改进的显式四步Runge-Kutta格式，并采用当地时间步长、隐式残值光顺加速收敛措施。

3.湍流模型的选取及数值求解技术研究。

本文主要选取和求解了一方程Spalart-Allmaras(S-A)模型，并将原始的一方程S-A湍流模型方程推导为守恒形式。

2020关于空气污染的英语演讲稿篇一：Teachers students:hello everybodyToday I lecture on the topic of air pollution. Air pollution is a new branch of atmospheric science it is to study in different weather conditions into the atmosphere of the pollutants in the atmosphere transmission dilute diffusion transformation and remove the rule and application of science. This subject originated from the 20XX s 20 xx years British atmospheric diffusion experiment was carried out but only in the '50 s the development of modern industry and city population is highly concentrated there appeared the serious urban or industrial pollution events in December 20 xx's London smog event for example took the lives of more than four thousand people these make people wide attention and researchof atmospheric pollution to the 60 s then gradually formed this new independent discipline.Air pollution due to human activity or natural process and out into the atmosphere into some harmful substances (pollutants) when the amount of discharged into enough (pollutant concentration up to a limit) makes the original clean air quality to drop if this situation is maintained long enough will be to humans animals plants and the atmosphere cause harm and adverse effects of the atmospheric state known as air pollution. Of air pollution has three elements: the concentration of pollution sources and pollutants harm to human and biological.Clean the atmosphere is one of the necessary conditions for the survival of humans in one person in five weeks no eating or five days without drinking water to be able to sustain life but not breathing air for more than 5 minutes then die the body to absorb every day 10-12 cubic meter of air. Thus eliminating air pollution or keep pollution concentration falls below a certain limit is how important.Pollution sources and pollutants discharged into the source of harmful substances into the atmosphere pollution sources harmful substances into the atmosphere pollutants. Atmospheric pollution source points of artificial and natural sourcesThe harm of air pollution and influenceAtmospheric pollution on human and environment caused by the harm and influence has gradually been recognied in the aggregate has the following several aspects:(1) the harm to human health. Human suffering has three pollute the air surface skin contact with theair inhaled and eating food containing atmospheric pollutants besides can cause respiratory and lung diseases but also on the cardiovascular system liver etc serious can take away the life.(2) the harm of biological. Animals because of the inhaled air pollution or eat foods containing contaminants and disease or death atmospheric pollutants can make the plant disease resistance drop influence the growth leaf spot wither or die.(3) the harm of items. Such as the textileclothing leather metal products construction materials culture art etc. chemical damage and defiled damage.(4) cause acidic precipitation such as agriculture forestry fresh water aquaculture.(5) destroys the high-altitude oone layer oone hole formation cause harm to human and biological survival environment.6. Impact on the global climate such as the increase in carbon dioxide and other greenhouse gases will cause the earth's atmosphere warms lead to increased global weather disasters and aerosol particles such as smoke increase the atmospheric turbidity solar radiation affect the longwaveradiation the earth may lead to abnormal weather climate.How to prevention and control of atmospheric pollution reduce the harm of air pollution and influence constitute a major and urgent research subject. Prevention and control of atmospheric pollutionPrevention and control of atmospheric pollution is a huge system engineering need to be individual and collective national and the joint efforts of the world can consider to take measures in the following aspects:(1) to reduce emissions. Use more pollution-free energy (such as solar energy wind energy hydroelectric power) reform the energy structure with low pollution energy (such as natural gas) pretreatment of fuel (such as coal desulfuriation) before such as improving combustion technology can reduce emissions. Inaddition before the pollutants into the atmosphere not use dust smoke abatement technology condensing technology liquid absorption technology recycling technology to eliminate some pollutants in the exhaust and can reduce the amount of pollutants into the atmosphere.(2) to curb emissions and make full use of atmospheric self-purification ability. Different meteorological conditions the capacity of the atmospheric pollutants into the same amount of pollutants the pollutant concentration was different.For wind good ventilation turbulence strong convection area and time atmospheric diffusion dilution ability is strong can accept more corporations to inversion region and time atmospheric diffusion dilution ability is weak cannot accept more pollutants otherwise itwill cause serious air pollution. Therefore respond to different regions different times for the effective control of emissions.(3) site selection design of chimney urban and industrial planning should be reasonable don't emitters transition concentration repeated superposition don't cause pollution formation of local serious pollution incident.(4) greening afforestation make more plants absorb pollutants reduce atmospheric pollution.Through the above explanation we know the importance of air for our human right from now on please protect the environment afforestation and create a better living environment!Today my speech is that under the flag of thank you.篇二：1. Power GenerationSiting fossil fuel power stations in mainly rural areas and distributing the pollution produced more evenly via tall chimneys has resulted in improved urban air quality though they still remain a major source of pollution mainly sulphur dioxide and nitrogen oxides.Better dispersion of pollutants emitted by tall chimneys leads to better dilution in the air and thus lower local concentrations of pollutants. This has however led to pollution being dispersed more widely and to transboundary air pollution.2. Other Industry and waste disposalAlthough fossil fuel power plants are the major source of industrial air pollution in many countries all industry and many businesses large and small can be significant local sources of a wide range of air pollutants.All waste has the potential to affect the environment adversely by contaminating the air soil orwater. Poorly managed waste disposal sites (landfill or incineration) can also pose a danger to public health through all these routes.3. Road TransportAir pollution from motor vehicles has in many countries replaced coal smoke as the major cause for concern; and the continuing growth in vehicle use means that efforts to reduce emissions from individual vehicles are in danger of being overtaken by increases in the volume of traffic.The air pollutants produced as a result of the use of motor vehicles present a two-stage problem: primary and secondary pollutants. Primary pollutants produced by petrol-powered vehicles include carbon monoxide nitric oxide benene particulate matter and lead. Much of the lead emitted by vehicles burning leaded petrol emerges as particles. Secondary pollutants produced as a result of the use of petrol-engined vehicles include nitrogen dioxide and oone.4. Domestic SourcesAs temperatures across the region plummeted domestic burning of coal across northern China becomes the primary source of air pollution. Other important domestic sources of air pollution are:Stoves and cookers produce carbon monoxide. If ventilation is inadequate or appliances poorly maintained CO may accumulate in dangerous concentrations. Nitrogen dioxide is also generated and concentrations in kitchens will usually exceed those outdoors when cookers are in use.Bonfires garden incinerators and barbecues can bea significant local smoke and odour nuisance. Burning garden waste produces smoke especially if it is damp and smouldering rather than dry and blaing. The smoke contains CO and other noxious and irritating compounds. Problems may be caused for asthmatics bronchitis sufferers or those with heart conditions. Even if the immediate health risk is small bonfires add to the general background level of air pollution.5. AgricultureAgricultural practices can also be a significant source of nuisance contributing both to local levels of air pollution and causing odour problems. The main sources of pollution are the burning of agricultural waste or of crops in the field and large intensive livestock units. Depending on soil type and fertilisation the nitrogen in the dung and urine of graing cattle contributes 20-40% of nitrous oxide emissions from agricultural land; methane is also emitted by cattle and other ruminants; nitrous oxide and methane are of course both greenhouse gases.。

四级高频词汇第1讲Albert Einstein:“Miracles are what happen when you get out of the way of yourself.关于词汇记忆The oppressed ________ freedom.A. requiresB. demandsC. requestsRequire: ask for firmlyDemand: the ruler sets a rule with the expectation that nobody would refute it.Request: ask for politelyentail【真题例句3】【v】尊重，重视Yet, being friendly is a virtue that many Americans value highly and expect from both neighbors and strangers.【真题例句12】【n】价值，重视Americans today don’t place a very high value on intellect.关于单词记忆法1、拆分联想记忆法in no cent a.无辜的天真无邪的re ti cent a.沉默寡言parallel趴了来哦lel lul level平lullabylull – baby2、谐音记忆法mortal a.致命的ponderous adj.笨重的、沉重的，文章冗长的labor v/n.劳动ambulance n. 救护车jeopardize v. 冒险3、形近对比记忆法adopt adapt adeptadopt v.收养采纳adapt v. 1. 适应~ oneself toShe adapted herself to the whole new environment2. 改编adaptableadept a.娴熟的be adept at be adept at making up the excusesConserve Preserve Reserve4、串记法同义串记：believe – hold – maintain – advocate – set forthsignificant – irreplaceable – vital – crucial—critical—unparalleled—striking 反义串记：tiny – humble – trivial – replaceable – negligible词性变换串记：reserve v./n reservation n. reservoir n.5、生活实景记忆法rejoice v.使高兴safeguard safe a. 安全的guard n/v保卫，守侯bodyguardglitter v. 发光（反射光）glare stare glowMars, a glowing red planet6、词根词缀记忆法词根(root) : to entitle the key meaning to a wordThe radio can _______signals.A transmitB emitmit=send trans=across e=outtransmit v. 投递式的发射emit v. 发散,发出词缀(affix):前缀（prefix）: to settle the emotion of a worde- = out, im- = in / notemigrant n.移居海外者immigrant n.移民，移居者后缀(suffix): to ascertain the word’s function-ate migrate to-ant migrantmigrant workers peasant workergrassroot modernizing forcesClude=closeexclude拒绝，排斥exclusion排除exclusive排外的，专用的exclusionism n.排外主义include 包括，包含inclusion inclusive inclusivenessConclude下结论conclusion conclusivepreclude防止，杜绝pre- pro- pri-preclusion排除，阻止preclusive除外的，妨碍的动词clude, 名词clusion, 形容词clusiveclos=clus=closeCloset n.壁橱，秘密会谈的、储藏物品的小房间Water Closet = WCvt.把…引进密室会谈a.私下的，隐秘的a closet discussionlavatory, restroom, bathroom, toiletjohn (n.)He’s a john.=He’s a pimp.(a man who is a prostitute's customer or patron)Can I whisper it?I want to see my aunt!disclose vt.揭露，泄露，透露enclose vt.围住，包住；附入，把装入信封envelopenclosure n.（四周有篱笆、围墙的）围场附件attachmentattach toattach importance to intellectualsGress=goProgress=pro（forward）+gress（go）“进步”make progress 进步Regress=re（back）+gress（go）“退步，退回”regression recession/depressiongive sb. easy access tocongress=con（together）+gress（go）“1、代表大会2、Congress美国国会”egress=e（out）+gress（go）走出去，所以是“出口”的意思ingress=in（in）+gress（go）走进来，所以是“入口”的意思progressive a.进步的，先进的，前进的aggress=ag（to）+gress（go）“进攻，侵略”aggression=ag（to）+gress（go）+ion“进攻，侵略”aggressive=ag（to）+gress（go）+ive“1、侵略的,好斗的2、敢作敢为的，有进取心的”Duc duct duce=leadpro`duce v.1、生产,制造2、显示，出示3、上演，制作`produce n.农产品`product n.1产品，产物；2、积，乘积by-`product n.副产品Side effectrepro`duce v.生殖;翻版;繁殖;复制,仿造Reproductive fertile fertility infertilitypro`ductive a.1、生产(性)的,能产的,多产的，富饶的2、富有成效的produc`tivity n.生产率，生产力con`duct v.1、引导,带领;2、处理,管理;3、指挥(乐队);4传导,传(热,电等)5、（oneself）表现`conduct n.举止，行为；管理（方式），实施（方式）con`ductor n.领队，指挥，列车长，售票员。

我的火星之旅英语作文现在完成时全文共3篇示例，供读者参考篇1I have just returned from the most incredible journey of my life - a trip to Mars! It still feels surreal to say those words out loud. As a young student, I had always dreamed of exploring the vast unknown of space, but never could I have imagined that I would be one of the first people to set foot on the red planet.The opportunity to be part of this historic mission has been a long and grueling process. I have dedicated countless hours to rigorous training, studying everything from astrophysics to survival skills. I have pushed my mind and body to the absolute limit, undergoing simulations that replicated the harsh Martian environment. The selection process alone has been brutal, with only the best and brightest candidates making the cut.As our spacecraft finally broke free from Earth's gravitational pull, a mix of excitement and trepidation washed over me. I have looked down at our beautiful blue planet from the window, wondering what wonders awaited us in the inky blackness of space. The journey itself has been arduous, with long stretches ofmonotony punctuated by critical maneuvers and course corrections.Upon entering Mars' orbit, our anticipation has reached a fever pitch. We have studied every inch of the planet from afar, but nothing could have prepared us for the breathtaking sight of the rusty red surface up close. As our lander detached from the mothership, we have held our breaths, knowing that this was the moment of truth.The descent through the thin Martian atmosphere has been harrowing, with our craft buffeted by turbulence and scorching temperatures. But our engineers have performed flawlessly, and before we knew it, our lander has touched down on the sandy regolith with a gentle thud.I have been the third to step out onto the surface, following in the footsteps of my two crewmates. As I have descended the lander's ramp, the stark, alien landscape has stretched out before me, and I have been struck by a profound sense of insignificance. In that moment, I have felt like a speck of dust in the vastness of the cosmos, humbled by the sheer scope of our achievement.We have spent weeks exploring and conducting experiments, soaking in every moment of this once-in-a-lifetime experience. I have walked where no human has walked before, my bootsleaving imprints in the rusty soil. I have collected samples and deployed scientific instruments, contributing to ourever-growing understanding of this enigmatic world.One of the highlights of our mission has been the opportunity to drive one of the rovers across the Martian terrain. As I have maneuvered the six-wheeled vehicle over rocks and craters, I have marveled at the ingenuity of human engineering that has made this all possible. We have even had the chance to explore the towering slopes of Olympus Mons, the largest volcano in the solar system.Of course, not everything has gone according to plan. We have encountered our fair share of challenges and setbacks, from equipment malfunctions to sudden dust storms that have forced us to take shelter. But through it all, our team has remained resilient, working together to overcome every obstacle in our path.As our time on Mars has drawn to a close, I have found myself growing wistful, already missing the otherworldly beauty of this desolate yet captivating world. Leaving our footprints behind has been bittersweet, knowing that we have accomplished something truly extraordinary, but also that we must now return to the familiarity of Earth.The journey home has been just as arduous as the outbound trip, with its own set of challenges and risks. But as our spacecraft has broken through the Earth's atmosphere, streaking across the night sky like a brilliant meteor, I have felt an overwhelming sense of pride and gratitude.I have gained a new perspective on our place in the universe,a humbling realization that we are but tiny specks in the grand scheme of things. Yet, at the same time, I have been inspired by the incredible feats we have achieved through human ingenuity and perseverance.As I have stepped back onto solid ground, enveloped in the warm embrace of Earth's atmosphere, I have been greeted by a hero's welcome. People from all walks of life have lined the streets, cheering and waving flags, united in celebration of our triumphant return.In the days and weeks since, I have been inundated with questions from curious minds, eager to learn about my experiences on the red planet. I have shared my stories and insights, hoping to inspire the next generation of explorers to reach for the stars, just as I once did.This journey to Mars has been the culmination of a lifelong dream, a testament to the boundless potential of humancuriosity and ambition. It has been an experience that has forever changed me, both as a student and as a human being. And though the memories may fade with time, the impact of this adventure will forever be etched into the fabric of my soul.篇2My Voyage to Mars in the Present Perfect TenseWell, here I am, back on Earth after the most incredible experience of my life - I have just returned from an expedition to Mars! It still feels surreal and I can scarcely believe that I have accomplished such an extraordinary feat. Let me recount the incredible journey that I have undertaken.It all began a few years ago when I first heard about the Mars Colonization Program being organized by the newly formed Interplanetary Exploration Corporation. They had put out a call for volunteer civilians to take part in humanity's first attempt at establishing a permanent settlement on the Red Planet. Despite the obvious risks and challenges, I leapt at the opportunity without hesitation. I have always been fascinated by space exploration ever since I was a little kid watching the Apollo missions on our old television set. To have the chance to actually travel to another world was a dream come true.The training process that I have gone through has been immensely rigorous, pushing me to my absolute limits both physically and mentally. I have spent countless hours in simulators, practicing everything from Mars surface operations to emergency protocols. The team of scientists and engineers have left no stone unturned in preparing us for every contingency. I have absorbed volumes of technical data on the systems of the spacecraft, life support equipment, Martian surface conditions and much more. It has been the most demanding educational experience of my life.Finally, after years of preparation, the day of launch arrived. I have never experienced such a heightened mixture of emotions - pride, apprehension, excitement and fear all wrapped into one. As the huge rocket engines roared to life beneath me, I could scarcely believe that my dream was becoming a reality. Theg-forces pressed me back into my seat as we climbed ever higher into the sky. Before I knew it, Earth had become a small blue marble hanging in the inky blackness, growing smaller with every passing moment.The journey through the void of space has been bothawe-inspiring and arduous. I have gazed out of the viewports in wonderment at the brilliant tapestry of stars unmared byatmosphere. I have seen the achingly beautiful colors of the Milky Way stretching across the heavens in a manner that can never be replicated on Earth. Looking upwards, the stars that had once seemed so distant and unreachable now surrounded me on all sides. Space is an endlessly captivating spectacle that never fails to leave me breathless.At the same time, the voyage has not been without its challenges. Living for months in the confined quarters of the spacecraft has taken its toll. Simple tasks like bathing and using the bathroom have become ordeals to be carefully managed. Meals have been nutritious but extremely bland affairs of freeze-dried food packages. I have missed the simple pleasures of fresh air, wide open spaces and home-cooked meals more than I can describe. Sleeping has also been difficult, with the constant background hum of machinery and faint vibrations passing through the hull. I have spent many hours staring sleeplessly out at the star fields, my mind dwelling on the immense distances between myself and my former life on Earth.At last, after nearly a year of transit, the rust-hued disc of Mars has grown larger and larger in our viewports with each passing week. I have watched it transform from a mere reddish dot into a geographically distinct world before my eyes. Finally,the dramatic moment of atmospheric entry and landing sequence arrived. I could feel the built up heat and pressure on the hull as we punched through Mars' thin atmosphere in a blaze of plasma. Then the parachutes deployed to further slow our descent for the final rocket-assisted landing. Setting down on the alien soil with adusty thump was an experience I have replayed in my mind a thousand times already.The first few weeks on Mars itself have been a flurry of intense work and exploration. I have helped assemble and test the primary habitat structures, life support systems, power generators and communication uplinks. Once the outpost was functionally established, the real adventure began. I have donned the compact but highly sophisticated exploration suits and ventured out onto the ruddy, dusty expanse to collect samples, study the geology and set up experiment packages. Every step outside has been monumental, an overwhelming feeling like I was the first human being to ever walk on this untamed world. Bounding across the rusty plains in the low Martian gravity felt intoxicatingly freeing, like playing at being an astronaut in my childhood fantasies.The Martian landscape has been rocky, desolate and unutterably ancient beyond my comprehension. I have seensweeping vistas of craters, canyons, desert dunes and mountain ranges that make the most rugged locales on Earth look tame by comparison. The sky overhead has had a haunting bloodred tint during the day, fading to inky purples and blacks at night and allowing the stars to shine through with spectacular brilliance. Sunsets and sunrises on this alien world have beenights to behold, with the tiny dot of our sun seeming to dangle much closer amidst strange blue, orange and violet hues splayed across the thin Martian sky.Life on Mars has certainly not been easy, but I have relished every moment. I have had to meticulously follow safety protocols and checklists for every task. Air, water and food have been severely rationed commodities on which my life depends. The habitats, though comfortable, often felt confining and made me yearn for the wide open vistas outside. Power requirements and allocation have also been a constant consideration, with everything from life support to experiment operations placing strains on our limited reservoir of energy.Nevertheless, I have gained experiences here that I could have never even imagined previously. I feel humbled to be among the first explorers of a new world, sole members of humanity to have stood on Martian soil and gazed upon itsotherworldly wonders. I have learned skills and performed duties that made me feel both insignificant and empowered in the same breath. Every day spent studying and working on this dusty alien globe has filled me with a deep sense of pride and accomplishment. I only lament that my time here has been so temporary.At long last, the crew transfer window opened up and our relief team arrived from Earth to rotate in and allow us to return home. Boarding the spacecraft for the return trip has been bittersweet. Part of me was overjoyed to finally be heading back to loved ones, comforts and the familiar grounds of my birthworld. Yet at the same time, I have felt a profound sense of loss at leaving this magnificent desolation behind. Mars has become a second home to me in a way, and I wonder if I have left a piece of my soul behind forever.As I have soared back through the inky celestial realm towards the Earth, I have spent countless hours reminiscing and poring over images, video logs and samples collected from my time on the Red Planet. I have traced the curves of ancient river valleys, run simulations of atmospheric phenomena, and analyzed soil and rock compositions again and again, as if attempting to sear every detail into my memory forever. In thosesilent moments drifting between worlds, I have felt a strange sense of melancholy, as though a part of me is no longer completely anchored to Earth.Finally, I have burst through the atmosphere in a blaze of heat and light, and splashed down in the waters of the Pacific to be picked up by recovery crews. Setting foot on Terra Firma once again has been an overwhelming experience. The air has tasted richer and sweeter than any wine, the colors and textures more vibrant than any memory, and the vast open spaces have filled me with a childlike sense of liberation. And yet, I have felt displaced to be back in this lush world of biological richness after so long traversing the stark, barren deserts of an alien land.As I sit here now typing out these words, my soul is still somewhere in transit, not fully settled on any one celestial shore. The journey that I have undertaken has profoundly changed my perspectives in both humbling and empowering ways. I have gazed upon our Earth, the only world in the universe that we know harbors life, hanging like a tiny jewel amid the cosmic enormity. Then I have walked across an entire other planet, untrodden before by any lifeform whatsoever, and gained new appreciation for how extraordinary and rare our existence truly is.I know not what the future holds, but one thing is certain - part of me will always remain on Mars, a piece of my being left behind on those dusty crimson plains to serve as the vanguard for humanity's greater destiny among the stars. The fire of exploration and discovery has been lit within my soul, never to be extinguished. I have been to Mars, and in so doing have taken one of the first small steps that will ultimately carry our species to the furthest reaches of the cosmos itself. That was my voyage, and it has forever changed me.篇3My Journey to MarsI have just returned from the most incredible adventure of my life - a journey to Mars as part of the first group of student explorers. The memories are still so fresh and vivid, almost as if I haven't even left the red planet yet.The preparation for this historic mission has been extensive and demanding. For the past two years, I have undergone rigorous training alongside nineteen other students from around the world. We have learned everything from piloting spacecraft to conducting scientific experiments,ResourceConsolidated survival skills on an alien world. The anticipation and excitementhave built with every simulation, every lecture, every grueling physical test.Finally, the day of launch arrived. I have boarded the massive interplanetary craft along with my crewmates, said my tear-filled goodbyes to family and friends on Earth through video calls, and strapped myself in as the tremendous rocket engines roared to life beneath us. The g-forces during liftoff have pushed me back in my seat like nothing I have ever experienced before. But my heart has raced with exhilaration, not fear, as our home planet has rapidly receded behind a fading cloud of vapor.The journey itself across the vast gulf of space between Earth and Mars has posed its own challenges that I have had to overcome. I have had to adapt to the confined living quarters, the simplistic food dispensed from pouches, the international crew who speak different languages. We have passed the long transit time training our minds and bodies, running experiments, and monitoring the spacecraft systems. Staring out of the small viewing windows, I have marveled at the breathtaking vistas of stars unsullied by atmospheric distortion. Several times we have made course corrections with precise rear bursts from the engines to ensure we remain on the correct trajectory.At last, after seven months of travel, the rusty-red disk of Mars has grown larger in our front viewing ports each day. The descent through the thin Martian atmosphere using heat shields and parachutes has been fierce but controlled. I have watched in amazement as the surface features - the flat northern plains, the gargantuan volcanoes, the yawning canyons - have rushed up to meet us. Finally, the retrorockets have fired in a deafening roar to slow our speed. Our landing craft has gently settled on the reddish, dusty ground in Chryse Planitia, and I have become one of the first humans to set foot on another planet.I have spent the last three months living and working in the Mars expedition habitat we have constructed ahead of time using autonomous rovers. Every day on Mars has been spent making discoveries and overcoming new obstacles. I have experienced the novelty and delight of donning a compact spacecraft and bouncing across the lower Martian gravity on short expeditions. I have extended the range of my explorations riding in a longrange rover, its large tires crunching across the coarse regolith. Using scoops, drills and analytical instruments, I have gathered soil and rock samples to examine their composition and structure, searching for any traces of past or present microbial life.I have scaled towering cliff escarpments to access deeper, older layers of the Martian crust that hold secrets about the planet's formation. I have deployed seismometers and meteorology instruments to probe the geologic activity of this small rocky world. Using remote cameras and satellites coordinating with controllers on Earth, I have carefully mapped the Martian surface in detail and searched for future human landing sites for more ambitious expeditions. I have witnessed every aspect of this alien world up close - the rusty hued sand and boulders, the pale ruddy sky, the rising twin moons, the heaving dust storms that can last for weeks, the bitterly cold conditions only survivable within a protective suit.Living in the compact Mars habitat has brought its own challenges that I have had to surmount. Our expedition crew has had to work in shifts to conserve precious air, water, food and energy within the habitat's closed-loop life support system. We have had to troubleshoot and repair malfunctions in the equipment using cleverness and limited resources, since nore-supply vehicles can reach us from Earth at a moment's notice. Most difficult has been maintaining team cohesion and morale during the long periods of confined isolation, with no visiting friends or family for months on end. We have had to support each other through the inevitable bouts of homesickness,distress and interpersonal tensions that arise from such extraordinarily stressful conditions.Now I have lifted off from Mars aboard the small transit vehicle with my crewmates, leaving behind the red desert panoramas that have become so familiar to me these past three months. As I have gazed out at the burnt-orange globe slowly shrinking behind us, I have felt a great sense of wonder and accomplishment at having been among the first explorers on this long-mysterious world. The journey back to Earth aboard this tiny craft has been just as arduousas the initial transit from Earth to Mars. I have had to be patient as we coast across the vast deep of space, cold and drifting. Finally, the atmosphere of Earth has rushed up and embraced our heat shields in a furious tornado of plasma. That flickering, turbulent inferno has at last deposited what remains of our craft in the Pacific Ocean, where we have breathed our first fresh breezes of terrestrial air and awaited retrieval.Having now returned to Earth, I have found that no amount of training or simulations could have prepared me for the majesty of being on Mars in person. I have seen landscapes and phenomena so unlike anything on my home planet. I have gathered data and samples that will unlock doors of newscientific knowledge. I have proven that human beings can travel across the cosmic ocean and establish a foothold, however small and temporary, on another world. And through it all, despite the hardships and loneliness endured, I have been forever transformed by this mind-opening experience of seeing Earth from the cosmic perspective as a pale blue haven of life in the darkness - our precious refuge in the vastness of space. I will carry the memories I have made on Mars for the rest of my days.。

我们学校最好的地方用英语写作文并且翻译My favourite place in school is the fantastic library which I borrow books.I go there three times a week.Many students go to library at noon, butit is very quiet.Most of the student go there for using computer, while others prefer to reading like me. I love reading, and I really enjoy it.It is a partof my life.Romance and horror are my best-loved.在学校我最喜欢的地方是很棒的图书馆借书。

我每周去三次。

许多学生中午去图书馆，但它很安静。

大多数的学生去使用电脑，而另一些人则更喜欢阅读喜欢我。

我喜欢阅读，我真的很喜欢它。

这是我生活的一部分。

浪漫和恐怖是我最喜欢的。

In our school, there are many trees and flowers. Students often gotoschool at seven o'clock. In the morning, we have four huors. We usually have lunch at about half past eleven. In the afternoon, we also have four classes. After the last class, we can go home. It is often at five o'clock. We have many interesting classes, so I like my school life。

Atmosphere大气Aerosol气溶胶质粒Ozonosphere臭氧层Greenhouse Gas温室气体Homosphere均质层Heterosphere非均质层Neutrosphere中性层Ionosphere电离层Troposphere对流层Stratosphere平流层Mesosphere中间层Thermosphere热层Exosphere外大气层、外逸层Lapse Rate of Temperature垂直温度递减率Inversion Layer逆温层Frictional Layer摩擦层Planetary Boundary Layer行星边界层Free Atmosphere自由大气Nacreous Cloud珠母云Tropopause对流层顶Stratopause平流层顶Mesopause中间层顶Thermopause热层顶Air Mass气团Air-mass Modification气团变性Arctic Air北极气团Antarctic Air南极气团Continental Air大陆气团Polar极地Tropical热带Marine Air海洋气团Equatorial Air赤道气团Cold Air Mass冷气团Warm Air Mass暖气团Front锋Frontal Zone锋区Frontal Surface锋面Frontal Line锋线Cold Front冷锋Warm Front暖锋Quasi-stationary Front准静止锋Occlusion Front锢囚锋Standard Atmosphere标准大气WMO世界气象组织Geopotential Height位势高度Meteorological Element气象要素Air Temperature气温Celsius’ Thermometric Scale摄氏温标Fahrenheit Thermometric Scale华氏温标Non-adiabatic Change非绝热变化Radiation辐射Conduction传导Convection对流Advection平流turbulence湍流Dry Adiabatic Lapse Rate干绝热垂直变温率Altimeter气压高度表Altimeter Setting气压高度表拨定Airspeed Meter空速表Atmospheric Pressure大气压强Station Pressure本站气压Surface Pressure场面气压Sea Level Pressure海平面气压QNH修正海平面气压高度表拨定QNE标准海平面气压高度表拨定Pressure Field气压场Isobaric Chart等压面图Geopotential Meter位势米Trough槽Ridge脊Col鞍？？？Air Humidity空气湿度Mixing Ratio混合比Specific Humidity比湿Saturation V apour Pressure饱和水汽压Dew Point Temperature露点温度Condensation Level凝结高度Wind风Wind Speed风速Wind Direction风向Geostrophic Wind地转风Buys Bullot白贝罗Convergence辐合Divergence辐散Cold Advection冷平流Warm Advection暖平流General Circulation大气环流Northeast Trade东北信风Southeast Trade东南信风Hadley Cell哈得莱环流Ferrel Cell费雷尔环流Monsoon季风Cloud云Atmospheric Stratification Stability大气层结稳定Emagram(Energy-per Unit-mass Diagram)埃玛图，T-lnp ChartStratification Curve层结曲线Hail冰雹Tornado龙卷Cloud Form云状Cloud Amount云量Cloud Height云高Precipitation降水Rain雨Drizzle毛毛雨Snow雪Graupel霰Ice Particle冰粒Ice Pellet冰丸Granular Snow米雪Dew露Frost霜Soft Rime针状雾淞Glaze冻雨Snow Cover on Runway跑道积雪Icing on Runway跑道结冰Fog雾Haze霾Smoke Screen烟幕Sand Storm沙尘暴Blowing Sand扬沙Dust浮尘Blowing Snow吹雪Thunderstorm雷暴Severe Storm强风暴Squall Line飑线Tornado龙卷风Atmospheric Transparency大气透明度Prevailing Visibility有效能见度Minimum V isibility最低能见度Flight Visibility空中能见度Visual Flight目视飞行Instrument Flight仪表飞行Meteorological Condition气象条件Meteorological Minimum最低气象条件Aerodrome Meteorological Minimum机场天气标准Jet/Jet Stream急流Subtropical Westerly Jet副热带西风急流Tropical Easterly Jet热带东风急流Low-level Wind Shear低空风切变V ertical Wind Shear风的垂直切变Horizontal Wind Shear风的水平切变V ertical Air Current Shear垂直气流切变Tail Wind Shear顺风切变Head Wind Shear逆风切变Cross Wind Shear侧风切变Gust Front阵风锋Individual Microburst单个微下击暴流Microburst lines微下击暴流线Wind Profile风廓线Prediction预报Warning警报Clear Air Turbulence晴空湍流Trailing V ortex Wakes尾涡湍流Richardson Number理查逊数Aircraft Icing/Aircraft Ice Accretion飞机积冰Dynamic Heat Effect动力增温效应Clear Ice明冰Rime Ice凇冰Glime毛冰？？？？Typhoon台风Tropical Cyclone热带气旋Mountain山区Plateau高原Surface Map/Surface Weather Chart地面天气图Isobaric Chart高空等压面图Isohypse等高线Isotherm等温线Trough-line槽线Shear-line切变线Auxiliary Weather Chart辅助天气图Cross-section Diagram剖面图Meteorogram气象实况图Hazardous Weather Phenomenon Chart危险天气现象图A viation Weather Forecast航空天气预报Synoptic System天气系统Synoptic Process天气过程Synoptic Situation天气形势Weather Prognostics天气形势预报Meteorological Element Forecast气象要素预报Atmospheric Model大气模式Numerical Model数值模式Synoptic Model天气学模式Statistical Model统计模式NWP/Numerical Weather Prediction数值天气预报Diagnostic Weather Analysis天气诊断分析法Aerodrome Forecast航站（机场）天气预报Air Route Forecast航线（航路）天气预报A viation Area Forecast区域航空天气预报Nowcast临近预报（超短时天气预报）V ery Short-range Forecast短时天气预报Short-range Forecast短期天气预报Landing Forecast着陆预报Take-off Forecast起飞预报Amended Forecast订正预报Flight Weather Forecast Bulletin飞行天气报告表Air Route Forecast Cross-section Diagram航线天气预报剖面图Aerodrome Weather Forecast Bulletin航站天气预报表Area Prognostic Chart区域天气预告图AIG WX/Significant Weather Forecast Chart重要天气预告图Upper Air Wind and Temperature Forecast Chart高空风、温度预告图A viation Meteorological Navigation航空气象导航。

The Atmospheric Waves of the Earths AtmosphereThe atmospheric waves of the Earth's atmosphere are a complex and fascinating phenomenon that have been studied by scientists for many years. These waves are responsible for a variety of weather patterns and can have a significant impact on our daily lives. In this response, we will explore the different types of atmospheric waves, their causes, and their effects on the planet.Atmospheric waves can be divided into two main categories: gravity waves and atmospheric tides. Gravity waves are caused by disturbances in the atmosphere, such as wind or temperature changes. They are named after gravity because they are influenced by the Earth's gravitational pull. Atmospheric tides, on the other hand, are caused by the gravitational pull of the moon and the sun. They are similar to ocean tides but occur in the atmosphere.Gravity waves can have a significant impact on the weather. They can cause turbulence, which can be dangerous for airplanes and other aircraft. They can also cause temperature changes, which can affect the formation of clouds and precipitation. In addition, gravity waves can create atmospheric oscillations, which can affect the movement of air masses and the formation of weather systems.Atmospheric tides are less well-known than gravity waves, but they can also have a significant impact on the weather. They are responsible for the regular movement of air masses and can affect the formation of weather systems. In addition, atmospheric tides can create atmospheric waves, which can cause turbulence and other weather phenomena.The causes of atmospheric waves are complex and varied. Gravity waves are caused by disturbances in the atmosphere, such as wind or temperature changes. They can also be caused by topographical features, such as mountains or valleys. Atmospheric tides are caused by the gravitational pull of the moon and the sun. They are similar to ocean tides but occur in the atmosphere.The effects of atmospheric waves on the planet are significant. They can affect the weather, the formation of clouds and precipitation, and the movement of air masses. They can also create turbulence, which can be dangerous for airplanes and other aircraft. In addition, atmospheric waves can affect the climate, as they can cause changes in temperature and precipitation patterns.In conclusion, the atmospheric waves of the Earth's atmosphere are a complex and fascinating phenomenon that have a significant impact on our daily lives. They are responsible for a variety of weather patterns and can affect the movement of air masses and the formation of weather systems. Scientists continue to study these waves in order to better understand their causes and effects, and to develop ways to predict and mitigate their impact on our planet.。

从别人身上学习优点As is vividly depicted in the picture, an thought-provoking idea that it is impossible for a person to learn nothing from any one hit upon the old man.Simple as the drawing is, the symbolic meaning is as deep as ocean. As a matter of fact, everyone has the merits and advantages superior than other people as well as drawbacks and disadvantages inferior than others. With the rapid developing society and economy, the fact remains that it is indispensable for anyone who wants to gain success to take full use of strongpoint, and more significantly, to learn from models from all walks of life and rectify our fault and shortcoming. Just as an provailing proverb says, ”two heads is always better than one”. On the whole, we can draw the conclusion that were there no the quality of learning from others, never would we both improve our ability and edify our sentiment.Accordingly, it is imperative for us to take some measures to advocate this virtue in our society. On the one hand, the government should constitute some policies to publicize the socialistic core value system to change for better. On the other hand, individuals in our society should be educated to cultivate this virtue by means of discovering and learning merits from other people around our surrounding. Only in this way can we achieve success at work and only in this way can we witness the ideal scene in which all members in our society live in an active and harmonious circumstance.保护传统文化There has been a heated discussion in the newspaper. As is vividly revealed in the photogragh, holding a piece of delicate and beautiful paper-cut of a lantern, the foreign man showed his great interest in traditional Chinese culture to others. Obviously, instead of being outdated, people in mounting numbers have been impressed by traditional Chinese culture in recent years.Simple as the picture is, the symbolic meaning is as deep as ocean. To begin with, the past decade has witnessed a huge development in economy in our country. Owing to the growth of our national economy and opening door policy, China faces the culture exchange with the outside world. An increasing number of foreign visitors from the whole world have been attracted by such Chinese folk art as paper-cut and china. On the other hand, for China, as for any other rapidly developing countries, however, there exists an extremely severe threat to age-old customs and traditions in the shadows of modernization. If paper-cut and china ever perished from the earth, it would be a tragedy of an immeasurable proportions for us.As a matter of fact, it has been universally acknowledged that preserving our traditional Chinese culture is of great significance to improve the soft power of our country. We should put great emphasis on protecting our traditional culture, despite bringing hope and pain at the same time. With a series of proper regulations concerning the protection of traditional heritage of our humanity being carried out, the future of our traditional Chinese culture will surely see an prosperity.下一代教育问题The future generation has never failed to arouse the extensive attention of the public. As is subtly portrayed in this funny drawing, a pair of parents, holding abucket and a mop, are following their son unpleasantly on his way to school. What the boy says illustrates that the duty of doing the cleaning at school will be finished by his parents. Obviously, it is extremely unbelievable that the parents has spoiled their son to this point.Absurd and odd as it is, the connotation inside the picture is as deep as ocean. As a consequence of family planning policy being carried out since the 1980s in China, families in mounting numbers feed only one child, who are dubbed as so called ”little emperor” or ”little princess”, which epitomizes the laziness and greed （self-indulgence）of these children. This phenomenon has triggered a devastating and unforeseeable influence on our society that our future generation might be unable to live independently. According to the latest schedule of the United Nation, the ability to live on their own of China’s primary school students ranks in the latter half when compared with other major countries. Overprotection by parents is nothing but a damage to the responsibility and sentiment of children. Were the tendency to continue, China will be bound to suffer great losses in the future competition with foreign countries.Accordingly, taking the severe effects of spoiling children into account, we must propagate the idea that hardly can delicate flowers under protection survive the intense competition in the outside world. Many experts have emphasized the significance of cultivate children’s ability to live on their own. That is a critical factor for the development of children in the future.实践的重要性As is symbolically illustrated in the cartoon above, on the ground stands a wandering man, with his hands in the pockets of his pants, looking at the ladder which leads to success. Quite regrettably, the idea of climbing the ladder up to achieve success has never occurred to him. The caption indicates that people like the man in the given cartoon will never achieve success.Simple as the picture is, what the cartoonist conveys to us is as deep as ocean. Of all the components of success, action seems to be hardest within our control. On the one hand, everyone in the world is eager for success, although it is indispensable to contribute much energy to the goals we aspire. As the competition in the real world is getting extremely intense, hardly can anyone perform his tasks or achieve his goals successfully without authentic action. On the other hand, the fact remains that there exists a majority of people who always shrink in front of difficulties. Being afraid of difficulties, they usually put hard work on the talk level and come up with some excuses to avoid hard work.As an old proverb put it, “all talk and no action is useless”. People in mounting numbers, however, have got defeated when encountered real hardship. Were the situation to continue, never would they taste the joy and happiness after conquering setbacks and gaining victory. It is imperative for us to publicize the opinion that hard work and action is nothing but a stepping-stone rather than a stumbling-block in the way towards success. Only in the way of daring to face difficulties in the process of accomplishing tasks can we concrete a more active world and can each member enjoy the happiness of success.The picture above has induced a heated discussion concerning the problem of taking care of senior citizens. As is subtly revealed in the cartoon, sitting in the chair in front of a mirror, an old lady is talking to her own image in the mirror to relieve the loneliness of being alone at home. Just as she says, ”my son is at work and my grandchild is at school, I feel a bit of lonely and boring.”Obviously, with a huge development in economy within the past decade, our society has entered the era of the so-called ”aging society”. It is an irreversible trend for us that a growing number of members have become old and entered an old age. As a consequence of having no one to talk to at home, large numbers of senior citizens have been suffering the loss of sense of security, identity and confidence, which is the so-called empty-nest syndrome. It is likely to constitute an unforeseeable and formidable problem to them owing to the lack of care from their relatives.Accordingly, taking the severe problem in our society into account, it is high time that we propagated the virtue of taking care of the old people. Many philosophies from Confucianism and Taoism in the traditional Chinese culture have emphasized the significance of taking care of the old people and reckoned it as a traditional Chinese virtue. That is to say, traditional Chinese values definitely goes hand in hand with the modernization of our country. If continue to inherit the valuable virtue of respecting and taking care of the senior citizens nicely, we will witness a more harmonious world. That is where taking care of senior citizens comes in.青少年教育不攀比As is vividly illustrated in the cartoon, surrounded by a crowd of admiring primary students at the school, a little boy is proudly showing his famous brand shoes of the latest style. Obviously, it is unbelievable that these children concentrate more on material comforts than the ability of learning.Simple as it is, the symbolic connotation is as deep as ocean. Families in mounting numbers have been becoming affluent in economy in recent years owing to the rapid development in our country. At the same time, parents usually inclined to give their children ample material conditions such as funny toys, expensive clothing, tasty food and so forth, thus gradually spoiling the future generation and preventing them from leading an independent life. Quite regrettably, the abundance of material comforts does not correlate with the rise of ability of learning and living. Hence, this phenomenon has triggered a severe damage to both our society and these children. Were the tendency to continue, our society would pay a high price to learn a lesson from it.As far as I’m concerned, it will cause intense turbulence in our country if we feed our future generation in such an indulgent way. In coping with the awful phenomenon, we should put the idea of striving for advancement in the process of learning rather than comparing material conditions at the core of the theory of our education. The time we educate our children in a more rational way is the time that we can surely believe that the future of our country is to change for better.The picture above has caused a heated discussion about self-confidence. As is subtly depicted in the given image, in front of a mirror stands a lovely cat, firmly believing that it is as strong as a lion. Obviously, it is confidence that makes it possible for the cat to reckon itself better than anyone else.Funny and exaggerated as the picture is, the symbolic connotation is thought-provoking. As a consequence of the rapid developing economic globalization, every individual are bound to encounter a variety of difficulties and problems, which are so tough that hardly can we conquer them. It is essential that self-confidence should be put at the core part in our mind. Just as a proverb puts it, when we face troubles and handicaps, however, “the final enemy is ourselves.” As a matter of fact, it has been universally acknowledged that self-confidence is the unexhausted source of our energy, our intelligence and our convincing power towards success. It is self-confidence which support us unwaveringly in the process of achieving success in all walks of life. That is where self-confidence comes in.In my view, facing a great number of difficulties and handicaps, we should bear in mind that self-confidence will definitely leads us to success. Everyone in our society should have the sense of self-confidence. Any trouble is nothing but a fake monster. Once we recognize its essence and acquire self-confidence, it will only be a matter of time before the victory becomes true.合作As is subtly revealed in the given portrayal above, with several big boxes in his hands, hardly can the young man carries them safely, which is defined as an addition effect. When he cooperates with another person by means of using a wooden board, they can easily carry large numbers of boxes which is 5 times than that one person can carry. Conversely, it is revealed as a multiplication effect. Obviously, it is cooperation that makes it possible for them to carry so many boxes without exhausting too much energy.Simple as the picture is, the purpose of the painter shows that teamwork is of great significance when we handle a variety of troubles and problems. With the rapid growth of economy and society, competition is becoming increasingly fierce. It is impossible for anyone to achieve success without teamwork and cooperation with others. Hence, people in mounting numbers put great emphasis on teamwork. As a matter of fact, it has been universally acknowledged that cooperation with copartners through all kinds of methods is one of the most essential qualification that anyone who wants to achieve success should possess. Placing cooperation in the core part of our mind can be justified on the grounds that it fits nicely with the theory of traditional Chinese culture.Accordingly, many philosophies from Confucianism and Taoism in traditional Chinese culture have emphasized the need to maintain a cooperative relationship with others. The competition being so serious, it is high time that a series of rules and regulations were worked out to encourage cooperation in the modern life. Everyone should acquire the ability of teamwork. Only in this way can we gain success and only in this way can we witness the ideal scene that our societyfunctions properly and actively in a harmonious atmosphere.网络As is subtly depicted in the given cartoon above, with a lovely smile face on the computer screen, the Internet contains too much personal information of people in mounting numbers, bringing convenience to the public. The easy access of private information to anyone, however, attaches a vicious face to the Internet in the shadow of its merits. Obviously, personal information security has gradually become a rather devastating problem hindering the rapid development of the Internet.文化交流As is vividly portrayed in the given cartoon above, carrying The Analects of Confucius, two westerners are applying the opportunities to become the students of Confucius, who is naturally associated with the traditional Chinese culture. At the same time, Confucius also wants to learn advanced culture from the western world to improve the modern civilized level of China. Obviously, this meeting of West and East has contributed to a culture blending, bringing hope and harmony at the same time.。