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The first ppt (0—0:20）Good morning everyone ! My name is Arvin. I come from the university of Science and Technology of China.Today I will discuss how to extract the hdyrogen by a new method.The second ppt （0:20—1:00）At present our environment is suffering from serious pollution, the blue sky has disappeared. We have to face the dreaded PM2.5 almost everyday. Why ? Why our environment become so bad. One of the important reasons is the overuse of fossil fuels, such as coal and oil. These fossil fuels have a great impact on our environment.The third ppt （1:00—1:45）Currently, the more serious problem is that the fossil energy is also vanishing rapidly. For the developing countries like china, the annual demand for energy is very large. However, Coal reserves can be only mined for 152 years and we can only use 40 years of oil. So it is emergency to find a apporpriate alternative.The fourth ppt （1:45—2:35）Hydrogen is a wonderful substitute,because it is a clean energy and also have high calorific value. There are a variety of ways to produce hydrogen. Such as biological、water electrolysis and Chemical methods. However, there methods are too expensive or unfriendly to the environment. So we propose a new method for producing hydrogen, weobtain hydrogen by the reaction of aluminum with water.The fifth ppt （2:35—3:20）If we want to use this way to extract hydrogen, we should solve two challenging problem, on the one hand, there is a native thin oxide layer on the aluminum surface which prevent water from reacting with aluminum. On the other hand, How to save the activated aluminum powder is also a big problem. Due to the activated aluminum powder is easy to be oxidized by air.The sixth ppt （3:20—3:58)In order to activate the aluminum, firstly, we add some additives into the aluminum to make alloys. Then alloy was milling with the salt. Salt can not only activate the aluminum but also protect it from air oxidation. With these methods, the aluminum can react with water at room temperature to release hydrogen.The seventh ppt (3:58—4:58)Next I will introduce some of the factors that affect the hydrogen evolution reaction. The first factor is temperature. From this graph, we can see that the conversion yield enhanced steadily with the increase of reaction time. And the hydrogen generation rate increases sharply when we increase the temperature of water.The Eighth ppt (4:58—5:50)The second factor is salt-to-aluminum mole ratio. This a indicatessalt-to-aluminum mole ratio. The following points can be concluded from this graph. First, the hydrogen evolution rate increases with the increase of the mole ratio, the total reaction time is shorter When the mole ratio is higher. Second, the conversion yield can reach sixty percent when the mole ratio is 1. However, if we raise the mole ratio above 1.5, the reaction efficiency can reach one hundred percent. Third, There is no significant difference betweeen the case with a=4 and a=7.The ninth ppt （5:50—6:48）The final factor is the effect of additives on hydrogen generation rate. From this picture we can see that hydrogen generation rate of alloys are greater than corresponding powders have no additives, The effect of adding Bi on the reaction rate is the most obvious, and the effect is the best. Additives also have the ability to omit delay time.The Tenth ppt （6:48—7:40）I have introduced that there is a dense oxide film on the surface of the aluminum. So we activate the aluminum by mechanical milling of aluminum and salt. Then we studied the effect of the salt-to-aluminum mole ratio on the hydrogen generation rate. And we find that the optimum salt-to-aluminum mole ratio was 4. Finally, we studied the effect of additives on hydrogen generation rate, Adding 7 wt% sillcon, graphite or bismuth additives can greatly increase the rate.The eleventh ppt （7:40—8:50）In the following research, we can use activated aluminum to react with saline Lake brine to extract the lithium. And we can study other more effective methods for activating aluminum powder, and we can use other better methods to produce hydrogen.Thank you ! Have any questions?。
Good morning/afternoon/evening. It is my great honor to stand here today and share with you my thoughts and insights on the topic of academic exchange. As we all know, academic exchange plays a crucial role in promoting the development of science, technology, and culture in our world. In this speech, I would like to discuss the significance of academic exchange, the challenges it faces, and the ways to overcome them.Firstly, let's talk about the significance of academic exchange. In today's globalized world, the boundaries between countries and cultures have become increasingly blurred. Academic exchange provides a platform for scholars, researchers, and students to share their knowledge, ideas, and experiences with their counterparts from other countries. This process not only enhances the mutual understanding and friendship between nations but also accelerates the progress of science and technology.Academic exchange contributes to the following aspects:1. Promoting the development of science and technology: Through academic exchange, researchers can learn about the latest achievements and trends in their respective fields, which can inspire them to innovate and develop new theories and technologies.2. Enhancing international cooperation: Academic exchange fosters cooperation between universities and research institutions across the world, leading to joint research projects and the sharing of resources.3. Cultivating global citizens: Students who participate in academic exchange programs can broaden their horizons, learn about different cultures, and develop a global perspective, which is essential for their future careers.However, despite its numerous benefits, academic exchange also faces some challenges. The following are some of the key challenges:1. Language barriers: Language differences can hinder effective communication between participants from different countries. To overcomethis challenge, it is essential to provide language training and translation services.2. Cultural differences: Cultural differences can lead to misunderstandings and conflicts among participants. It is crucial to promote cultural awareness and respect among individuals involved in academic exchange.3. Financial constraints: Many scholars and students may find itdifficult to afford the costs associated with academic exchange programs, such as travel expenses, accommodation, and tuition fees. This barrier needs to be addressed through scholarships, grants, and other funding mechanisms.To ensure the success of academic exchange, the following strategies can be adopted:1. Strengthening language and cultural training: Providing comprehensive language and cultural training can help participants overcome communication barriers and adapt to the new environment.2. Enhancing funding opportunities: Establishing scholarships, grants, and financial aid programs can make academic exchange more accessible to a broader range of individuals.3. Promoting international partnerships: Encouraging universities and research institutions to establish partnerships can facilitate joint research projects and academic exchange programs.4. Utilizing technology: Leveraging technology, such as online collaboration tools and virtual conferences, can make academic exchange more accessible and efficient.In conclusion, academic exchange is a powerful tool for promoting the development of science, technology, and culture. By addressing the challenges and implementing effective strategies, we can create a more inclusive and collaborative global academic community. Let us all work together to harness the potential of academic exchange and contribute to the betterment of our world.Thank you for your attention.。
30sGood afternoon, everyone. The title of the paper is Visible Microspectroscopy for Diagnosis of Gastric Precancer. Its author is Liu Yong from Department of Physics, Zhao qing University. It’s presented by Li Mengfan from CAS, Hefei Institutes of Physical Science. You can know more about cancer and the new method to diagnose gastric precancer after reading this paper.58sCancer is very common among human beings. It is mostly related to the habit of the patients, the job, the environment, the drinking water and the soil matters, too. If a person is affected by certain bacteria, he may also get gastric cancer. Bad habits like smoking, drinking, mental tension, eating improperly and living irregularly increase the possibility of having cancer. Before specific treatment, the doctor should make sure whether the patient has cancer and where the focus is. The method used to diagnose cancer and locate thecancerous area is very important.42sBefore we design a method to diagnose cancer, we should know more about cancer like where it starts and what it causes.Firstly, about 90% of the human’s cancer start from the epithelial layer of skin, internal organs and tubular organs in the body. Secondly ,cancer usually accompanied by the changes of organization structure in the cell level.So, the changes which appear in the structure of organization and chemical composition provides important evidence for diagnosis of precancer.42sNormal method to diagnose gastric precancer is Reflectance spectroscopy. It’s very prospective in early diagnosis of cancer and is commonly used these years.One of the most common technology is diffuse reflectance visible spectroscopy, it can acquire the approximate information of the target tissue. This method is low cost, fast and non-invasive, it provides important means for diagnosis of malignant damage of organization of human organs. However, there are also some disadvantages of this method which need to be improved.55sThis is the system of diffuse reflectance spectroscopy, the light beam emitted from the tungsten halogen lamp is guided into the integral ball by the source fiber. The light come out of the integral ball irradiate the standard board, the reflected light of the standard board is treated as the background. Then take target tissue substitute for the standard board, and scan the reflected light of it. The reflected light spectra of the gastric tissue mucosal layer and the submucosa layer is guided into the spectrometer by the collector fiber. The spectrometer and the computer is connected by USB, spectrum can be processed using computer.36sFirst of all, only average visible spectrum of the target tissue can be acquired, it means that the docters cannot make out the location of the cancerous tissue precisely.What’s more, the device is easy to be affected by changes of optical path length induced by different set-up of prober and the variation of hemoglobin concentration due to the pressure between prober and tissue.50sTo avoid the problems of the commonly used techniques, diffuse reflectance visible spectroscopy, scientists do a lot of researches to find out a new way to diagnose precancer.The new method is Visible Microspectroscopy. The visible microspectroscopic measurement device is accomplished on the basis of fiber confocal microscope, its 3-d imaging principle devote to the optical tomography ability of the system.The visible microspectrum of cancerous and normal tissue can be analysed andcontrasted, so it’s more useful than the normal method.45sThis is the structure of the visible microspectroscopy device .The fiber coupler can separate the lighting beams from the signal beam. The two lens can focus the light on the tissue ,The 3-D electronic controlled platform move along the direction of optic axis, so that the device can acquire the visible microspectroscopy signal of the sample in different depth, precisely locate the boundary of the cancerous tissue.The signal measured from different position can be stored in the computer after analysed by the spectrometer.31sThis is the spectrum chart of the normal tissue and cancerous tissue, they are analyzed by the spectrometer before being transmitted to the computer. The upper chart is the visible spectrum of normal tissue, it is regular. Contrasting to this, in the nether chart, the spectrum of the cancerous area shows that the strength of reflected light grows as the wave length grows.49sIn comparison with the normal method, there are a lot of advantages of the new method.Firstly, the structure of visible microspectroscopy device is very simple. The main parts consist of source, fiber coupler, 3-D electronic controlled platform, spectrometer and the computer.Secondly, the 3-D space microspectrum can be acquired , which can help the doctors efficiently make out whether the gastric tissue is cancerous.What’s more, the optical tomography ability enabled the device to precisely locate the edge of the cancerous area.32si.In conclusion, the main goal of this research is to find a new way to diagnose thegastric precancer.ii.The spectrum of the normal and cancerous gastric tissues which can be measured by visible microspectroscopy in cell level is the central idea .iii.This new method can obtain the cell level information, and is not affected bychanges of optical path length and hemoglobin concentration.50si. The device is very simple, so it can have a small size, which can reduce the sufferings of patients.It can efficiently make out whether the tissue is canceration.ii. Besides, the 3-D space microspectrum and optical tomography ability can make the device accurately distinguish the cancerous tumor area from the normal tissue in cell level, thus the boundary of the cancerous tissue can be ascertained accurately.iii. The result of the research shows that this device may be used to non-invasively diagnosis of early gastric cancer.20sThis device is only researched in the lab, there are still a lot of works to do to make this device applied into practice. So, s pecial design of this device should be made which can be applied to the medical diagnosis.给大家推荐一个英语微信群Empty Your Cup英语微信群是目前学习英语最有效的方法，群里都是说英语，没有半个中文，而且规则非常严格，是一个超级不错的英语学习环境，群里有好多英语超好的超牛逼的人，还有鬼佬和外国美眉。
