demonstrate that magnesium
小学上册F卷英语第五单元期中试卷
小学上册英语第五单元期中试卷英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.What is the capital of South Korea?A. SeoulB. BusanC. IncheonD. DaeguA2. A _______ is a reaction that occurs in the presence of oxygen.3.The ________ (cake) looks delicious.4.The dolphin can leap high out of the _______ (水).5.The girl loves to ________.6. A rabbit's teeth never stop ______ (生长).7.What is the name of the bear that loves honey?A. PandaB. Polar BearC. Winnie-the-PoohD. Grizzly BearC8.The first man to dive into the Mariana Trench was _______. (维尔德)9.The cake is ________ (装饰得很美).10. A saturated fat is solid at ______ temperature.11.How many months have 28 days?A. 1B. 2C. 12D. 0C12.Which animal is known for its ability to change colors?A. ChameleonB. ParrotC. SnakeD. GoldfishA Chameleon13. civilization is known for its advanced ________ (天文学). The Maya14.Which month has 30 days?A. JanuaryB. FebruaryC. AprilD. MarchC15.The sun is _______ (在升起).16.The study of ancient climates is called ______.17.What is the capital of Georgia?A. TbilisiB. BatumiC. KutaisiD. RustaviA18.I love learning about climate change and how to protect the __________.19.Granite is an example of an ______ rock that forms from cooled magma.20.The ______ (鲸鱼) sings beautiful songs underwater.21.What is the capital of France?A. BerlinB. MadridC. RomeD. ParisD22.The __________ is the main source of food for many animals.23.The baby is _____ in the crib. (sleeping)24.The chemical symbol for lead is _______.25.What is the name of the famous mountain range that includes Mount Everest?A. AndesB. RockiesC. HimalayasD. AlpsC26.The invention of the telegraph transformed long-distance _____.27. A ________ (草丛) provides shelter for wildlife.28.My _____ (弟弟) loves to play soccer.29.What do we call the fear of heights?A. ClaustrophobiaB. AgoraphobiaC. AcrophobiaD. Nyctophobia30.The chemical formula for phosphoric acid is ______.31.The process of making bread rise is caused by _______ production.32.What is the main ingredient in bread?A. SugarB. WaterC. FlourD. Salt33.The chemical formula for aspirin is ________.34.What do you call a frozen dessert made from milk or cream?A. CakeB. PieC. Ice CreamD. PuddingC35.What is the term for a baby goat?A. CalfB. KidC. FoalD. LambB36.How many hours are in a day?A. 12B. 24C. 36D. 4837.The _____ (常青树) stays green all year round.38.What do we call a shape with four equal sides?A. RectangleB. SquareC. TriangleD. Pentagon39.My toy ____ is a great listener. (玩具名称)40.The scientist conducts important _____ (研究) on health.41.Her name is . (她的名字是。
小学上册第十一次英语第3单元真题试卷
小学上册英语第3单元真题试卷英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.The chemical symbol for magnesium is ______.2.How many colors are in a rainbow?A. 5B. 6C. 7D. 83.What do we call the leader of a country?A. PresidentB. MayorC. GovernorD. SenatorA4.My favorite subject is ________.5.How many colors are in the flag of Canada?A. OneB. TwoC. ThreeD. Four6.The ancient Greeks held ________ to celebrate athletic competition.7.Which fruit is yellow and curved?A. AppleB. GrapeC. BananaD. OrangeC8.My neighborhood is very ________ (安静) and friendly. Everyone knows each other.9.My grandma enjoys sharing her __________ (传统).10.The chemical formula for glucose is ______.11.The Earth's crust is thickest under ______ and thinnest under the oceans.12.The _____ (果汁) is delicious and refreshing.13.They are _____ (sitting) on the grass.14. A _____ can be hot or cold.15.The __________ is a famous area known for its crystal-clear waters.16.What is the capital of Jamaica?A. NassauB. KingstonC. Port-au-PrinceD. HavanaB17.I want to ________ a new bike.18.What is the capital of Kazakhstan?A. AlmatyB. Nur-SultanC. ShymkentD. Atyrau19.What type of animal is a dolphin?A. FishB. ReptileC. MammalD. AmphibianC20.Which animal is known as "man's best friend"?A. CatB. DogC. RabbitD. Bird21.What do we call the process of taking in food and breaking it down?A. DigestionB. RespirationC. MetabolismD. AbsorptionA Digestion22.The first electronic computer was created in _______. (1940年)23.What is the capital of Bolivia?A. La PazB. SucreC. Santa CruzD. CochabambaA La Paz24.I have a pet _______ who likes to jump (我有一只喜欢跳的宠物_______).25.What do we call the force that pulls objects toward the Earth?A. MagnetismB. FrictionC. GravityD. InertiaC26. A ____(community garden) fosters local cooperation.27.What is the name of the small, red fruit that is often mistaken for a vegetable?A. TomatoB. PeachC. CherryD. StrawberryA28.Which day comes after Friday?A. ThursdayB. SaturdayC. SundayD. MondayB29. A _____ can provide information about the history of our solar system.30.What do we call the study of fungi?A. MycologyB. BotanyC. ZoologyD. EcologyA31.I enjoy outdoor activities like ________ (远足) and ________ (野餐) with my family.32.The __________ is important for agriculture and food production.33.What do you call a large body of saltwater?A. RiverB. OceanC. LakeD. PondB34.Creating a compost pile can benefit your garden's ______ and soil health. (创建堆肥可以改善你花园的土壤质量和健康。
demonstrates
demonstratesDemonstratesIntroductionIn today's fast-paced world, effective communication is key to successful business dealings and social interactions. Demonstrations play a crucial role in conveying information, ideas, or processes in a clear and concise manner. Whether it is demonstrating a product, a concept, or a procedure, a well-executed demonstration can effectively engage an audience and leave a lasting impression. This document will explore the importance of demonstrations, the essential elements for a successful demonstration, and provide tips on how to deliver an impactful and convincing demonstration.The Importance of DemonstrationsDemonstrations hold significant importance in various fields, including sales, education, training, and entertainment. They offer a visual and interactive approach to conveying information, making it easier for the audience to understandand retain the presented information. Here are a few reasons why demonstrations are essential:1. Clarity: Demonstrations provide a hands-on experience, allowing the audience to see and comprehend complex ideas or processes more easily.2. Engagement: Demonstrations capture and maintain the attention of the audience, creating a memorable and interactive experience.3. Persuasion: A well-executed demonstration can be highly persuasive, showcasing the benefits and advantages of a product or concept.4. Skill Development: Demonstrations are an effective way to teach practical skills, as they provide a step-by-step guide to the process being demonstrated.Essential Elements of a Successful DemonstrationTo ensure a successful demonstration, certain elements must be considered and incorporated into the presentation. Let's explore these essential elements:1. Clear Objective: Start by defining the objective of the demonstration. Determine what you want to achieve and tailor your presentation accordingly.2. Detailed Planning: Thoroughly plan each step of the demonstration, from the materials and props needed to the sequence of actions. This will help you stay organized and avoid any unforeseen hurdles during the presentation.3. Engaging Opening: Capture the attention of your audience right from the beginning by incorporating an engaging opening. Highlight the benefits or advantages of the product or concept you are demonstrating, and create curiosity or excitement among the viewers.4. Step-by-Step Instructions: Break down the process into clear and concise steps, ensuring that each action is explained thoroughly. Make sure to speak clearly and provide ample time for the audience to understand each step before moving on.5. Visual Aids: Utilize visual aids such as charts, diagrams, or props to enhance the demonstration. Visuals can reinforce the information being presented and make it easier for the audience to grasp the concepts.6. Interaction: Encourage audience participation by inviting questions, comments, or even asking for volunteers to assist in the demonstration. This will create a more interactive and engaging atmosphere, where audience members feel involved and valued.7. Troubleshooting: Anticipate any potential issues that may arise during the demonstration and prepare solutions or workarounds in advance. This will help you maintain confidence and professionalism even in challenging situations.8. Summary and Recap: Conclude the demonstration with a summary and recap of the main points covered. This will reinforce the key takeaways for the audience and ensure they leave with a clear understanding of the information presented.Tips for Delivering an Impactful DemonstrationTo make your demonstration truly impactful and convincing, consider the following tips:1. Practice: Practice your demonstration multiple times to ensure smooth transitions and confident delivery. Familiarize yourself with the materials, props, or equipment you will be using, and rehearse the timing of each step.2. Be Enthusiastic: Show enthusiasm and passion for the subject matter you are demonstrating. Your energy will help captivate the audience and maintain their interest throughout the presentation.3. Use Stories and Examples: Incorporate real-life examples or anecdotal stories to make the demonstration relatable and memorable. This will help the audience connect emotionally with the information being presented.4. Use Visual Cues: Utilize hand gestures, facial expressions, or body language to emphasize key points or important information. Visual cues can enhance the delivery of your demonstration and make it more engaging for the audience.5. Tailor to the Audience: Understand your audience and customize your demonstration accordingly. Consider their background knowledge, interests, and needs. This will ensure that your demonstration meets their specific expectations and requirements.6. Timing: Pay attention to the timing of your demonstration. Being mindful of the allotted time will allow you to stay on track and deliver the necessary information without rushing or dragging the presentation.ConclusionDemonstrations are an effective and powerful tool for conveying information, ideas, and processes. By incorporating the essential elements discussed in this document and following the tips provided, you can deliver a successful and impactful demonstration that engages, persuades, and educates your audience. Whether in sales, education, or any other field, mastering the art of demonstrating will undoubtedly enhance your communication skills and ensure greater success in your endeavors.。
术后疼痛管理的进展(双语)
Non-Steroidal Anti-inflammatory Drugs and Cyclooxygenase (COX-2) Inhibitors 非甾体抗炎药和环氧化酶(cox - 2)抑制剂
NSAIDs have become the cornerstone in the treatment of acute pain in the early postoperative period because of its opioid sparing effect. 非甾体抗炎药(NSAIDs)已成为基石,由于在治疗急性疼痛的术后早 期它能减少阿片类用药量。 Administration of ibuprofen and oxycodone in combination provides superior and effective analgesia in the postoperative period. 布洛芬和羟考酮结合能提供优质、有效的术后镇痛。 The combination of ibuprofen and acetaminophen has also been reported to reduce the need for early analgesia up to 34% in children undergoing tonsillectomy. 布洛芬和对乙酰氨基酚的联合应用也有报道在儿童进行扁桃腺切 除术，减少早期镇痛需要量34%。
Management of Postoperative Pain 术后疼痛管理
福建医科大学附属协和医院麻醉科规培住院医师 李婷
Pharmacological Options 药理选项
Opioids Opioids are effective analgesics for moderate to severe pain. They act on opioid receptors in the peripheral and central nervous system. However their efficacy is limited by side effects. Opioids and/or NSAIDs combined with local anesthetic infiltration or regional block has proven to be a useful technique for controlling pain in patients after ambulatory surgery and should be considered whenever possible. In most studies local anesthetic infiltration with systemic opioids or NSAIDs showed improvement in an algesia, better recovery and shortening of discharge time from day surgery unit. or moderate to severe pain. 阿片类药物对于中度到重度的疼痛是有效的镇痛药。他们作用 于外周边和中枢神经系统阿片受体。然而他们的功效受限于副 作用。阿片类药物和/或非甾体类抗炎药结合局部麻醉剂渗透作 用或区域阻滞已经被证明是一个有用的技术来控制日间手术后 患者的疼痛, 应尽可能考虑。大多数研究证明，对于日间手术或 中至重度的疼痛，局部麻醉渗透作用联合系统性阿片类药物或 非甾体类抗炎药，有助于改善镇痛,更好的恢复,加快出院时间。
FDTD Solutions资料集锦专题资料(四)
defined local structures.
Numerical study of natural convection in porous media (metals)
using Lattice Boltzmann Method (LBM).pdf 自然对流多孔介质(金属)用晶格玻尔兹曼方法加快的数值研究
The use of latent heat storage, microencapsulated phase change
materials (MEPCMs), is one of the most efficient ways of storing thermal energy and it has received a growing attention in the past
评价的线性和非线性光学聚合物的二次电光系数衰减全反射技术
The impact of local resonance on the enhanced transmission and dispersion of surface resonances.pdf 局部表面共振对传输和分散增强的影响
We investigate the enhanced transmission through the square array
decade.
Plasmonic Nanoclusters Near Field Properties of the Fano
Resonance Interrogated with SERS.pdf 近场法诺共振制备电浆的性能研究
Review on thermal transport in high porosity cellular metal
高通量计算集成机器学习催化描述符设计新型二维MXenes析氢催化剂
高通量计算集成机器学习催化描述符设计新型二维MXenes析氢催化剂摘要：二维MXenes作为一种具有优异催化性能的材料，其析氢性能的研究显得尤为重要。
然而，传统的试错方法耗费时间和资源，难以大规模筛选出性能优异的MXenes。
因此，我们提出了一种基于高通量计算和机器学习的催化描述符设计方法，以加速和优化MXenes的析氢性能预测和发现过程。
本文首先通过大量密度泛函理论计算筛选出112种可能的析氢MXenes，并通过Fe原子掺杂进一步优化其析氢性能，得到7种性能优异的Fe doped MXenes。
接着，我们基于多项式回归、随机森林和支持向量回归等机器学习算法构建了基于17种物理和化学性质的催化描述符，并通过训练集和测试集的误差分析，选择了随机森林作为最佳预测模型。
最后，我们使用该模型预测了所有112种MXenes的析氢性能，并发现了15种前所未有的性能优异MXenes，其中析氢活性高于Ni和Pd催化剂，且可能具有实际应用价值。
关键词：MXenes；催化描述符；高通量计算；机器学习；析氢。
Abstract:As a kind of material with excellent catalytic performance, the study of hydrogen evolution performance of two-dimensional MXenes is particularly important. However, traditional trial-and-errormethods are time-consuming and resource-consuming, making it difficult to screen MXenes with excellent performance on a large scale. Therefore, we propose a catalytic descriptor design method based on high-throughput computing and machine learning to accelerate and optimize the prediction and discovery process of MXenes' hydrogen evolution performance. In this paper, 112 possible hydrogen evolution MXenes were screened through a large number of density functional theory calculations, and 7 performance-excellent Fe-doped MXenes were further optimized by Fe doping. Then, based on machine learning algorithms such as polynomial regression, random forest, and support vector regression, we constructed catalytic descriptors based on 17 physical and chemical properties, and selected random forest as the best prediction model through the error analysis of the training set and test set. Finally, we used this model to predict the hydrogen evolution performance of all 112 MXenes, and discovered 15 performance-excellent MXenes that have not been seen before, among which hydrogen evolution activity is higher than that of Ni and Pd catalysts, and may have practical application value.Keywords: MXenes; catalytic descriptors; high-throughput computing; machine learning; hydrogen evolution。
2024届浙江省杭州学军中学高三上学期模拟测试英语试卷(2)
1. What can we learn about the woman’s watch?A．It’s 5 minutes fast.B．It doesn’t work.C．It’s 5 minutes slow.2.A．Go to the town.B．Tour the campus.C．Give an interview.D．Visit the school clubs.3. What are the speakers mainly talking about?A．A film.B．A class.C．The homework.4. What do we know about the man?A．He hasn’t been home for long.B．He doesn’t like the new job.C．He might miss this town.5.A．He hates to buy tickets all the times.B．They can afford to buy a ticket next October.C．Buying a yearly ticket can save him much money.D．The woman is too busy to visit the garden again within a year.二、听力选择题6. 听下面一段较长对话，回答以下小题。
1. What is the relationship between the speakers?A．Co-workers.B．Fellow tourists.C．Traveler and agent.2. What are the speakers discussing?A．Beijing culture.B．Beijing’s tourist attractions.C．Beijingers’ life in Hutong.7. 听下面一段较长对话，回答以下小题。
托福规律总结(修订版)
语法总结1. 词性：看该词后面修饰的是什么词，副词修饰形容词、动词，形容词修饰名词；如果是用and连接的并列结构，看前后并列的成分都是什么词性a. 名词与形容词e.g. 1. Fuel is any substance or material that reacts chemically with another substance ormaterial to produce hot (改为heat). (p85.27)2. The world’s water balance is regulated by the constant circulation of water in liquidand vapor form among the oceans, the atmospheric (改为atmosphere) , and the land.(p164.16)b. 形容词与副词e.g. At the National Archives, a repository for records of the United States government,visitors can view the originally (改为original) Declaration of Independence. (p99.36)c. 名词与动词e.g. Four different types of remembering are ordinarily distinguished by psychologists:recollection, recall, recognize (改为recognization), and relearning. (p59.29)d. 形容词与动词e.g. The aim of the decorative arts is to beautiful (改为beautify) our surroundings.(p165.22)2. 时态：句子中要注意时态一致，注意时间副词a. 过去的事情一定用过去时；e.g. The Spanish claiming (改为claimed) title to all of North America and established theoldest city in the United States, St. Augustine, Florida, in 1565. (p58.17)b. 在过去某一个时间点已经完成的用过去完成时；e.g. By 1899 Ransom Olds had establish (改为established) in Detroit, Michigan, the firstfactory in the United States for the manufacture of automobiles. (p84.16)c. 现在仍持续中的用现在完成时；e.g. The care of children during their years of relative helplessness appears to have being(改为been) the chief incentive for the evolution of family structures. (p178.26)d. 表示一般性的陈述和客观规律的用一般现在时。
材料科学与工程专业英语
Aluminum alloys are best known for low density and corrosion resistance. Electrical conductivity,ease of fabrication, and appearance铝合金是最知名的低密度和耐腐蚀性。
的导电性，易于制造，并且外观Magnesium alloys have even lower density than aluminum镁合金具有更低的密度比铝metallic 金属的corrosion 腐蚀ductile 延展ball bearing 滚珠轴承multiphase 多相wrought 加工的，精细的malleable 可锻的有延展性的Smelt 熔炼，精炼More than 90% by weight of the metallic materials used by human beings are ferrous alloys.超过90％（重量）用于人类的金属材料是铁类合金。
Within the steel category, we shall distinguish whether or not a significant amount of alloying elements other than carbon is used.对于钢的区分，我们要弄清楚的是是否含有有效量的合金元素而不是碳的含量。
◆low alloy and high alloy steels.低合金钢和高合金钢。
◆These alloy additions are chosen carefully because they invariably bring with themsharply increased material costs. They are justified only by essential improvements in properties such as higher strength or improved corrosion resistance这些合金元素都经过精心挑选，因为他们总是给他们带来大幅增加的材料成本。
Salt A guide to protecting turbine air inlets in m
The book of Salt A guide to protecting turbine air inlets in maritime environmentsThe maritime environment can be an unforgiving place when it comes to operating andmaintaining complex rotating equipment such as gas turbines. Yet equipment failure canlead to substantial downtime, lost revenues and expensive repair bills.Whether located on a ship, an offshore platform, FPSO or in a coastal region, turbinesare required to operate in some of the most severe weather conditions on the planet.Hurricanes in the Gulf of Mexico, savage storms in the North Sea, and cyclones in theSouth China Sea are just a few examples of what can be expected.The Marine EnvironmentIn order to operate in such harsh conditions a turbine must have a superior air inletprotection system. And this system must be of a design proven to cope not only withextreme weather, but also with the maritime atmosphere’s other potent weapon - Salt!97% of all the water on earth is saline, and this is estimatedto add up to a total of 50,000,000,000,000,000 tonnes ofdissolved salts in the world’s oceans, seas andsaltwater lakes.The ocean’s principal (~85%) dissolved solids are sodiumchloride or common salt. Other constituents are calciumsalts (calcium carbonate and calcium sulfate), potassiumsalts (potassium sulfate), and magnesium salts (magnesiumchloride, magnesium sulfate, and magnesium bromide).S alt & Sali ni tyThe average salinity of the oceans is around 3.5%, whereasfresh water typically contains less than 0.1% salt. The DeadSea is the world’s most saline large body of water with a salt content of over 30%.The majority of airborne salt aerosols are formed when wave action causes air to become trapped within the sea water. This air then rises to the surface as bubbles. When these bubbles burst, small sea water droplets are expelled into the atmosphere.The amount and make-up of the aerosols is a function of wind and sea state, i.e. strongwinds lead to more droplets of a larger size being ejected into the atmosphere.Salt AerosolsDuring high winds it is also possible for sea spray to become directly entrained in a gust of wind, but generally the aerosol droplets formed during this process are very large and remain airborne for only a matter of seconds.The Marine Boundary Layer (MBL) is the portion of the atmosphere directly above and affected by the sea surface. The MBL extends for many thousands of metres in height, but it is normally the first 50 metres that is of main relevance when considering the impact of salt aerosols.Extensive studies have been conducted into the salt aerosol concentration in the lower MBL. Although there is wide variation in the absolute figures, almost all studies concur onthe fact that concentration is a function of wind speed.The Marine Boundary LayerParker Hannifin has adopted the MMBL Salt Concentration Standard as it provides a conservative, yet realistic figure for the year-round average salt levels in the lower MBL throughout the world.Depending on the ambient relative humidity (RH), sea salt can exist as dry or wetted particles, or as solution droplets. At levels of humidity above 75%, sea salt aerosols are always in liquid form. As the RH falls below 75% and towards 40%, water from the droplets evaporates and they begin to take on a ‘sticky’, semi-solid form. Once below 40% the salt aerosol will essentially consist of solid salt particles.However, reversing the process sees a different result - that is to say that as the RH increases above 40%, salt particles retain their basic solid characteristics. This remains the case until the humidity reaches around 65%, at which point the particles rapidlydeliquesce back to liquid droplets.Wet or DryDuring the change of phase from liquid to solid, the salt aerosol will undergo a substantial change in size. For example, a liquid salt droplet at 90% RH will contract to about 25% of its original size as it becomes a solid particle below 40% RH.The ingestion of airborne salt has been proven to be a major contributing factor in both decreased turbine performance and reduced engine lifetime. This is easier to understand when considering the amount of inlet air consumed by gas turbines. For example, a 15 MW unit may require 110 lb/s (50 kg/s) of air. If this air contains 0.1 ppm of sea salt aerosol, then after only 2000 hours of operation the turbine will have ingested ~80lb (36 kg) of salt. Salt aerosols, like any other contaminant, can damage a turbine through the following mechanisms: erosion, cooling-path blockage, fouling and corrosion. But, it is the lattertwo which are most often associated with salt.The Need for Salt FiltrationFouling of the compressor blades can be a particular problem. A poor filtration system can allow salt build-up to affect the compressor’s aerodynamic efficiency. Althoughcompressor washing at regular intervals can alleviate this, it also introduces the danger of washing salt into other parts of the turbine.Ingested sea salt can cause corrosion problems throughout the turbine, but it is normallyhot corrosion associated with post-combustion sections of the turbine that are of mostconcern. Hot corrosion is a complex process, but can be considered to be the acceleratedattack of turbine materials by molten sulfates (primarily sodium sulfate). The process isoften known as sulfidation.Sodium sulfate (Na2SO4) is present in sea salt, but most often occurs when sodiumchloride and sulfur react during combustion. The sulfur is almost always supplied by thefuel, while the sodium chloride can be the result of contaminated fuel or insufficient inletair filtration.Hot Corrosion and SulfidationIn order for sodium sulfate to attack turbine materials, it must be in a molten state.However, the melting point of Na2SO4shifts downwards when in the presence of sodiumchloride. This reduction can be from over 1600ºF (~875 ºC) to as low as 1110ºF (~600ºC), which greatly increases the potential for corrosion.Many filtration companies have a poor understanding of the marine environment and the special requirements of gas turbines. Their approach is to try to utilize inlet systems developed for land-based applications, and often ones that have not been optimized to protect turbines.The use of such systems generally results in turbine problems. This is unsurprisingconsidering that the level of salt in a typical land-based location is less than 0.008 ppm, whereas the offshore equivalent is 0.1 ppm, rising to over 10 ppm during severe storms.Furthermore, many systems fail to be able to deal with salt in both dry and wet forms.Approaches to Salt FiltrationParker Hannifin has a different philosophy. All Parker Hannifin products are developed specifically with the protection of gas turbines in mind. And all of our offshore, coastal and marine systems utilize SRS Technology.Clearly it is important to be sure that a filtration system is, or will be, providing adequate protection. Turbine manufacturers often provide a salt inlet limit for their engines, typically as an average (or average and maximum) sodium chloride ppm level.The onus is then on the providers of filtration systems to demonstrate that theirequipment will meet this criteria. But when assessing the performance of a system it is essential to know the details of any testing. For example, if the output of a system is claimed to be 0.001 ppm, what input was the product subjected to? This input must be viewed not only in terms of input concentration, but also aerosol size distribution.Input/Output — The NumbersThe use of standardized aerosol inputs is one solution to this problem, and Parker Hannifin utilizes the MMBL standard which defines both concentration and a detailed droplet size distribution. This is similar to the NGTE 30 knot aerosol standard. However, while the use of these standards is helpful in comparing alternative systems, nothing can beat an in-depth knowledge of the conditions at the actual system location.Our approach to salt filtration evolved from test work in the early 1970’s with propulsionturbines on warships. This provided the understanding that salt aerosols can enteran inlet in both wet and dry states, and when dry aerosols are captured by a filter, asubsequent rise in humidity could result in a phase change.Having gained an understanding of the environment, we set about producing afiltration solution, and SRS Technology was born. SRS Technology is not a product,but more a technical philosophy that is utilized in all Parker Hannifin maritime GTprotection systems.The Parker Hannifin Approach —SRS TechnologyThe SRS Technology concept requires the use of three core stages, but can beaugmented with additional stages to suit particular environments. Stage 1 removescoarse salt aerosols, precipitation, and bulk seawater. Stage 2 is a filter/coalescer whichcaptures dry particulates including salt, and also facilitates the coalescence of finesaltwater droplets into larger ones. Stage 3 captures droplets that have been re-entrainedinto the air from Stage 2.For more information, contact your Parker Hannifin Gas Turbine Filtration representative: 11501 Outlook Street, Suite 100 | Overland Park, KS 66211T: +1.800.821.2222 | T: +1.816.356.8400 | F: +1.816.353.18733 Omega Park | Alton, GU34 2QE | United KingdomT: +44 (0) 1420 541188 | F: 44 (0) 1420 541298Email:*****************************/gtf。
钒钛磁铁矿金属化球团还原冶炼中钒的行为
Trans.Nonferrous Met.Soc.China30(2020)1687−1696Behavior of vanadium during reduction and smelting ofvanadium titanomagnetite metallized pelletsShuai WANG,Yu-feng GUO,Fu-qiang ZHENG,Feng CHEN,Ling-zhi YANG,Tao JIANG,Guan-zhou QIUSchool of Minerals Processing and Bioengineering,Central South University,Changsha410083,ChinaReceived10October2019;accepted9April2020Abstract:The effects of CaO content,MgO content and smelting temperature on the vanadium behavior during the smelting of vanadium titanomagnetite metallized pellets were investigated.The thermodynamics of reduction and distribution of vanadium was analyzed and the high-temperature smelting experiments were carried out.The thermodynamic calculations show that the distribution ratio of vanadium between the slag and the hot metal decreases with the increments of CaO and MgO content in the slag as well as the increase of the smelting temperature.The smelting experiments demonstrate that the vanadium content in iron and the recovery rate of vanadium in pig iron increase as the CaO content,MgO content and smelting temperature increase,whereas the vanadium distribution ratio between the slag and iron tends to decrease.Moreover,the recovery rate of vanadium in pig iron has a rising trend with increasing the optical basicity of the slag.The addition of MgO in the slag to increase the slag optical basicity can not only improve the vanadium reduction but also promote the formation of magnesium-containing anosovite,which is beneficial to following titanium extraction.Key words:vanadium;vanadium titanomagnetite;vanadium distribution ratio;electric-furnace titanium slag;MgO1IntroductionVanadium titanomagnetite ore serves as an important feedstock for production of vanadium[1]. Currently,the blast furnace(BF)process and the direct reduction-electric furnace(DR-EF)process have been commercialized to recover iron and vanadium,but titanium resource cannot be recovered cost-effectively due to low TiO2contents of slags[1−4].Compared with the BF process,the DR-EF process is easier to control for the reduction of oxides because the reductant addition can be accurately adjusted in electric furnace,and the DR-EF process has the advantages such as environmental friendliness and good quality of productions[2,3].Therefore,the DR-EF process should be developed to produce titanium slag for following titanium extraction[5−10].In the DR-EF smelting process,vanadium oxides and iron oxides are reduced to molten iron, while titanium oxides are enriched in slag. Vanadium-bearing molten iron is oxidized to produce semisteel and vanadium slag;then vanadium is extracted from the vanadium slag by hydrometallurgy methods[1−4,11,12].Thus, reduction and distribution behaviors of vanadium during the smelting of vanadium titanomagnetite by the DR-EF process are crucial for subsequent vanadium recovery.Reduction and distribution behaviors of vanadium between slag and hot metal have been reported in many previous studies[13−26].JUNG et al[16]and SHIN et al[17]indicated that the vanadium distribution ratio between slag and molten iron increased with the increase of slag basicity but decreased with the rise of temperature. However,WANG et al[23]showed that theFoundation item:Project(2019JJ50816)supported by the Natural Science Foundation of Hunan Province,China Corresponding author:Yu-feng GUO;Tel:+86-731-88830346;E-mail:*************.cnDOI:10.1016/S1003-6326(20)65330-4Shuai WANG,et al/Trans.Nonferrous Met.Soc.China30(2020)1687−1696 1688distribution ratio of vanadium between titanium slag and molten iron decreased as the basicity increased from0.35to1.28.Additionally,YAN et al[21]also indicated that high temperature,low TiO2content and high binary basicity of slag were beneficial to decreasing the vanadium distribution ratio between blast furnace slag and metal. NAN[25]proposed that high temperature and increased basicity were beneficial to the reduction of vanadium oxides in blast furnace hearth.The opposite conclusion concerning the impact of slag basicity in previous papers could be explained by strong oxygen potential conditions in the investigations of JUNG et al[16]and SHIN et al[17].Moreover,previous researchers mainly focused on the vanadium behavior between the metal and ordinary slag or titanium slag with a low TiO2content.The behavior of vanadium between molten iron and titanium slag with a high TiO2 content is still not clear.In this study,the used vanadium titanomagnetite has a low silica and high titania and the addition of CaO and MgO were applied to adjusting slag composition.The effects of CaO content,MgO content and smelting temperature were analyzed thermodynamically and studied experimentally in an electric furnace.Moreover,the relationships among the slag optical basicity, CaO/MgO mole ratio and vanadium distribution ratio between the slag and the molten iron and vanadium recovery rate in pig iron were also discussed.These findings will support the development of the DR-EF process for the comprehensive utilization of vanadium titano-magnetite ore.2Experimental2.1Materials and methodsThe raw material for producing vanadium titanomagnetite metalized pellets used in this study was taken from the Panxi region of China.The metallized pellet mainly contains71.38wt.%total iron,15.53wt.%TiO2,0.82wt.%V2O5and 3.71wt.%SiO2[5].All of chemicals and reagents utilized of this study are of analytical grade.The details of electric furnace and experimental steps have been described in our previous papers[5,8]. The metallized pellet powders were prepared by crusing the pellet and then mixed with additives (CaO,MgO)and graphite.The mixture was placed in a graphite crucible and smelted in the electric furnace at various temperatures under the protection of high purity argon gas.After the given smelting duration of20min,the sample was removed from the furnace and rapidly cooled under the protection of argon gas.At last,the vanadium-bearing pig iron and titanium slag were separated and crushed for subsequent analysis.2.2Definition of parameters(1)Vanadium distribution ratio(L V)The vanadium distribution ratio between the titanium slag and the molten iron is expressed assVm(V)(V)cLc=(1) where c s(V)and c m(V)represent the contents of elemental vanadium in the titanium slag and the molten iron,respectively.(2)Vanadium recovery rate(ηV)The recovery rate of vanadium in pig iron is calculated by Eq.(2),and we also use the following expression to analyze the distributions of V between slag and iron:V PIVMPV MP=100%w mw mη⋅⨯⋅(2)where w V and w MPV are the mass fractions of V in pig iron and vanadium-bearing titanomagnetite metallized pellets(wt.%),respectively;m PI and m MP are the masses of pig iron and vanadium-bearing titanomagnetite metallized pellets(g),respectively.2.3Analysis and characterizationFactSage®7.1software[27]was adopted to predict the distribution behavior of vanadium during the smelting process.The“Equilib”module with the databases“FactPS”and“FToxid”was used. Besides,it should be mentioned that the value of the FactSage prediction might be not very accurate due to the insufficient thermodynamic data about vanadium oxides in its database.Nevertheless,the predicted trends may be correct and can be used to guide the experiments.The chemical composition of the titanium slag was determined by X-ray fluorescence(XRF)technique(PANalytical,The Netherlands).The vanadium content in the iron was determined by chemical analysis method.Shuai WANG,et al/Trans.Nonferrous Met.Soc.China30(2020)1687−169616893Thermodynamic analysis and calculationsIn general,vanadium is in the form of vanadium spinel(FeO∙V2O3)in the vanadium titanomagnetite concentrate,and its reduction processes by solid carbon are expressed as Reactions(3)−(5)[28].The temperatures of these reactions are higher than1339.1,2008.1and 1375K,respectively.The metallized pellet was produced from the vanadium titanomagnetite concentrate pellet by the coal-based direct reduction in a rotary kiln at1373K with a C/Fe mole ratio of 1:1for3h[5,8].Therefore,it is clear that the vanadium oxides in the metallized pellets could be reduced to low valence vanadium oxides. FeO·V2O3(s)+2C(s)=Fe(s)+2VO(s)+2CO(g),Δr G mΘ=426928−318.82T(3) VO(s)+C(s)=V(s)+CO(g),Δr G mΘ=310493−154.62T(4) VO(s)+C(s)=[V]+CO(g),Δr G mΘ=289768−210.64T(5) (V2+)+(O2−)+C=[V]+CO(6) According to Reaction(6),it can be inferred that the slag composition may influence the vanadium reduction and distribution.Thus,the effects of slag composition and smelting temperature on the vanadium distribution ratio between slag and metal were calculated and discussed as follows.3.1CaO additionAs we know,the low valence vanadium oxides (such as VO)are basic oxides in titanium slag during the smelting process.According to the ionic theory of molten slag[24],CaO is a strongly basic oxide which can donate oxygen ion(O2−)in molten slag.For the reduction of basic oxide,increasing slag basicity can promote the transformation of vanadium from slag to hot metal[24].The effect of CaO content on the vanadium distribution ratio between the slag and the iron was analyzed by FactSage®software with a constant MgO content of 10wt.%in the titanium slag and smelting temperature of1823K.As shown in Fig.1(a),the distribution ratio of vanadium(L V)between the slag and iron decreases with the increase of the CaO content in slag.This trend is similar to previous works[21,23].3.2MgO additionThe effect of MgO content on the vanadium distribution ratio was calculated with a constant CaO/SiO2mass ratio of 1.0and smelting temperature of1823K.As shown in Fig.1(b), the vanadium distribution ratio decreases withtheFig.1Effects of CaO content(a),MgO content(b)and smelting temperature(c)on vanadium distribution ratio between slag and molten iron(predicted by FactSage 7.1)Shuai WANG,et al/Trans.Nonferrous Met.Soc.China30(2020)1687−1696 1690increase of the MgO content in slag.Thus,similarto the influence of CaO,the vanadium distribution ratio decreases as the MgO content increases.The strength of basic oxide is related with the electrostatic potential of cations.The lower the electrostatic potential of cations is,the stronger the basicity of the corresponding oxide.The CaO is more basic than MgO due to the fact that the electrostatic potential of Ca2+(1.89)is lower than that of Mg2+(3.08)[28].By comparing Fig.1(a) with Fig.1(b),the effect of MgO on the vanadium distribution is weaker than that of CaO because CaO is more basic than MgO.3.3Smelting temperatureFigure1(c)shows the effect of smelting temperature on the distribution ratio of vanadium under a fixed slag composition.The vanadium distribution ratio decreases as the smelting temperature increases.This trend can be explained by the enhancement of endothermic reduction (Reaction(5))of vanadium oxides with increasing the temperature.4Results and discussion4.1Effects of CaO contentHigh-temperature smelting experiments were conducted to investigate the effects of CaO content on the vanadium behavior during the smelting of vanadium titanomagnetite metallized pellets.A series of experiments were carried out at1823K for 20min with2wt.%reductant.The experiments were carried out in a carbon crucible with graphite addition under high purity argon atmosphere resulting in a very low oxygen potential during the smelting process.As shown in Fig.2(a),it can be seen that the content of vanadium in the hot iron tends to increase as the CaO content increases. Figure2(b)shows that the distribution ratio of vanadium between the slag and the molten iron decreases with increasing the CaO content.As shown in Fig.2(c),the recovery rate of vanadium in pig iron also increases with an increase in CaO content in slag.This trend is in agreement with the above thermodynamic analysis and previous investigations[21,23].According to the above thermodynamic analysis,increasing CaO content can improve the reduction of vanadium oxides and promote the vanadium transfer from slag tomolten Fig.2Effects of CaO content in slag on vanadium content in pig iron(a),vanadium distribution ratio(b) and vanadium recovery rate in pig iron(c)iron.Besides,the increase of CaO content in slagcan also reduce the viscosity and improve thefluidity of slag,therefore strengthening the dynamic condition of reduction reactions[29].Thus,the increase of CaO content can improvethe thermodynamic and dynamic conditions forthe recovery of vanadium during the smeltingprocess.Shuai WANG,et al/Trans.Nonferrous Met.Soc.China 30(2020)1687−169616914.2Effects of MgO contentThe effects of MgO content on the vanadium behavior were investigated at the smelting temperature of 1823K for 20min with the reductant addition of 2wt.%and constant CaO content.Figure 3(a)shows that the reduction of vanadium oxides is promoted and the vanadium content in the molten iron increases with the increasing MgO content in the slag.Figure3(b)Fig.3Effects of MgO content in slag on vanadium content in pig iron (a),vanadium distribution ratio (b)and vanadium recovery rate in pig iron (c)illustrates that the vanadium distribution ratio decreases as the MgO content increases.Furthermore,as shown in Fig.3(c),the recovery rate of vanadium in pig iron has an increase tendency with increasing the MgO content in the slag.This trend is consistent with the thermodynamic analysis.The addition of MgO can improve the thermodynamic condition to improve the reduction of vanadium oxides during the smelting process.Moreover,similar with CaO,the increase of MgO in slag can also reduce slag viscosity [29]and improve the fluidity of slag so that promote the recovery of vanadium in pig iron.HOWARD et al [30]showed that the presence of MgO had no significant influence on vanadium distribution,which was attributed to high FeO content and too low content of MgO.4.3Effects of smelting temperatureThe effects of smelting temperature on the vanadium behavior were studied at a fixed slag composition,20min duration and 2wt.%reductant.Figures 4(a)and 4(b)show that the vanadium content in the iron increases as the smelting temperature increases,whereas the vanadium content decreases after the temperature is above 1848K.The vanadium distribution ratio decreases when the smelting temperature increases from 1798to 1848K and it increases with the further increase of temperature.Figure 4(c)shows that the recovery rate of vanadium in pig iron increases when the smelting temperature increases from 1798to 1848K,whereas it decreases at higher smelting temperature.Previous investigations [16,17,21,26]indicated that the vanadium distribution ratio between slag and hot metal decreased as smelting temperature increased.It can be explained that increasing smelting temperature can improve the thermodynamic conditions of recovery of vanadium in pig iron.However,the higher smelting temperature will cause the over-reduction of titanium-bearing slag,which can deteriorate the fluidity of slag.This means the dynamic conditions probably are bad for the recovery of vanadium at higher temperature.Therefore,to achieve the higher recovery rate of vanadium in pig iron,reduce energy consumption and suppress the reduction of titanium oxides [8],the smelting temperature should be controlled to be not too high.Shuai WANG,et al/Trans.Nonferrous Met.Soc.China30(2020)1687−16961692Fig.4Effects of smelting temperature on vanadium content in pig iron(a),vanadium distribution ratio(b) and vanadium recovery rate in pig iron(c)4.4Effects of optical basicityThe optical basicity of the oxides melt can be regarded as its tendency to liberate oxide ions and has a significant influence on the oxides reduction. Therefore,the relationship between the optical basicity of the slag and the V behavior was discussed to investigate the influence of slag composition.The relationship of the optical basicity of slag and the vanadium distribution ratio and vanadium recovery rate in pig iron was discussed as follows.The optical basicity[31]of the slag was calculated asB B1nBΛ=χΛ=⋅∑(7) whereΛB represents the optical basicity of each oxide[28,31],andχB represents the mole fraction of positive ion in each oxide.The optical basicity and the mole fraction of each oxide in the slag are listed in Table1and Table2,respectively.Additionally, previous studies[32,33]indicated that the vanadium oxide did not contribute to the optical basicity of the melts,and the vanadium oxide content in the slag is very tiny.Thus,the vanadium oxide was ignored in the calculation of the optical basicity of the slag in the present study.Table1Optical basicity of each oxideOxide CaO SiO2MgO TiO2Al2O3ΛB 1.000.480.780.610.605As illustrated in Fig.5(a),the vanadium distribution ratio between the slag and the molten iron decreases as the optical basicity increases. Figure5(b)shows that there is an increase tendency in the recovery rate of vanadium with the increase in the optical basicity of slag.It can be explained that the free oxygen ion(O2−)in the slag increases as the optical basicity increases,which is beneficial to the reduction of vanadium oxides from the thermodynamic view.Consistently,the previous studies[21,23]also showed that the increase of basicity could improve vanadium oxide reduction and decrease vanadium distribution ratio between titanium slag and metal.However,some investigators[14,18,26]reported that the increasing slag basicity suppressed the reduction of vanadium oxide and increased the vanadium distribution ratio between slag and metal.This difference might be as a result of a very high range of FeO used and high oxygen potential in their investigations.Under the high oxygen potential condition,the vanadium oxide would exist as high valence vanadium oxide (such as V2O5),which is an acidic oxide and could cause the opposite conclusion to this study(low valence vanadium oxide in slag under low oxygen potential)according to thermodynamic analysis. Furthermore,the increase of optical basicity of slagShuai WANG,et al/Trans.Nonferrous Met.Soc.China 30(2020)1687−16961693Table 2Mole fractions of each oxide in slag and corresponding optical basicity No.Temperature /KMole fraction of oxide/%Optical basicityCaO SiO 2MgO V 2O 3TiO 2Al 2O 3C11823 5.75518.55119.7140.42944.23911.3120.6133C2182315.00416.05015.2440.25444.2969.1500.6332C3182316.61815.31715.3130.15643.6628.9330.6381C4182316.92714.95714.9470.20244.5998.3690.6391C5182317.10014.35014.3730.049345.8828.2460.6398C6182317.68814.69414.5850.10344.4818.4480.6409M7182316.92614.95614.9460.20844.5978.3680.6391M8182316.46914.79416.4580.14043.6958.4440.6399M9182315.91214.27318.0200.15543.5798.0610.6413M10182315.48013.66821.0430.08042.3987.3310.6449M11182314.72413.49923.2630.071141.0437.3990.6459Fig.5Effect of optical basicity of slag on vanadium distribution ratio (a)and vanadium recovery rate in pig iron (b)will increase the O 2−ion amounts in molten slag,thus improving the fluidity of slag and the dynamic conditions of recovery of vanadium in pig iron.4.5Effect of CaO/MgO mole ratioThe above results indicated that the increase of the slag optical basicity and the smelting temperature could decrease the vanadium distribution ratio between the slag and iron and increase the recovery rate of vanadium in pig iron.The vanadium reduction was improved by adding CaO and MgO in the slag,as well as increasing the smelting temperature.Furthermore,the extraction of titanium resource from the enriched titanium slag should be considered to achieve the comprehensive utilization of vanadium titanomagnetite.The main Ti-bearing phase is important for titanium extraction by acid leaching due to different acid solubilities of titanates.It is proven that increasing the proportion of MgTi 2O 5phase in titanium slag results in a higher acid solubility ratio due to its good acid solubility [34],whereas CaTiO 3has a poor acid solubility [35].Moreover,the increment of MgO content in titnaium slag is beneficial to MgTi 2O 5formation and the CaO addition prefers to CaTiO 3formation.Reducing CaTiO 3proportion and increasing MgTi 2O 5in slag is beneficial to titanium extraction by acid leaching.Therefore,the effects of the mole ratio of CaO/MgO on the vanadium distribution ratio and recovery rate of vanadium in pig iron are shown in Fig.6.As illustrated in Fig.6,the vanadium distribution ratio decreases when the CaO/MgO mole ratio increases from about 0.4to 0.8,and then it has insignificant changes with the further increase of the CaO/MgO mole ratio.This trend could beShuai WANG,et al/Trans.Nonferrous Met.Soc.China30(2020)1687−16961694Fig.6Effects of CaO/MgO mole ratio in slag on vanadium distribution ratio(a)and vanadium recovery rate in pig iron(b)explained by the thermodynamic improvement of reduction of vanadium oxides with an increment of CaO/MgO mole ratio;on the other hand,the CaO/MgO additions simply improved the slag viscosity in this high titania slag and thereby made it easy for the reduction of vanadium oxides(Vox) and improved the dynamic conditions.Furthermore, with the limited addition of CaO,MgO can be added during the smelting process for the promotion of the vanadium reduction.In conclusion, both CaO and MgO are basic oxides,and adding MgO to increase the optical basicity of titanium slag can not only improve the recovery of vanadium in pig iron but also be beneficial to titanium extraction by acid leaching.5Conclusions(1)The reduction and distribution behaviors of vanadium during the smelting of vanadium titanomagnetite metallized pellets were studied.The thermodynamics of additions of CaO and MgO and smelting temperature on the reduction and distribution of vanadium was analyzed and the various high temperature smelting experiments were conducted.(2)The thermodynamic analysis indicated that increasing CaO content,MgO content or optical basicity in slag can improve the recovery of V in pig iron from the viewpoint of thermodynamics. The results of experiments showed that the additions of CaO and MgO in the high titania slag could improve the reduction of vanadium oxides and increase the recovery rate of vanadium in pig iron.The smelting temperature should not be higher than1848K to suppress the reduction of titanium oxides and achieve high recovery rate of vanadium in pig iron.(3)The distribution ratio of vanadium between the high titania slag and the molten iron trended to decrease and the recovery rate of vanadium in pig iron trended to increase as the slag optical basicity increased.With the limited addition of CaO,adding MgO to increase the optical basicity of titanium slag could not only improve the recovery of vanadium but also be beneficial to titanium extraction by acid leaching.References[1]MOSKALYK R R,ALFANTAZI A M.Processing ofvanadium:A review[J].Minerals Engineering,2003,16(9): 793−805.[2]FU Wei-guo,WEN Yong-cai,XIE Hong-en.Development ofintensified technologies of vanadium-bearing titanomagnetite smelting[J].Journal of Iron and Steel Research, International,2011,18(4):7−10.[3]ROHRMANN B.Vanadium in South Africa(metal reviewseries No.2)[J].Journal of the Southern African Institute of Mining and Metallurgy,1985,85(5):141−150.[4]STEINBERG W,GEYSER W,NELL J.The history anddevelopment of the pyrometallurgical processes at Evraz Highveld Steel&Vanadium[J].Journal of the Southern African Institute of Mining and Metallurgy,2011,111(10): 705−710.[5]JIANG Tao,WANG Shuai,GUO Yu-feng,CHEN Feng,ZHENG Fu-qiang.Effects of basicity and MgO in slag on the behaviors of smelting vanadium titanomagnetite in the direct reduction-electric furnace process[J].Metals,2016, 6(5):107.[6]ZHANG Wen-sheng,ZHU Zhao-wu,CHENG Chu-yong.Aliterature review of titanium metallurgical processes[J].Hydrometallurgy,2011,108(3−4):177−188.[7]ZHENG Fu-qiang,GUO Yu-feng,LIU Shui-shi,QIUShuai WANG,et al/Trans.Nonferrous Met.Soc.China30(2020)1687−16961695Guan-zhou,CHEN Feng,JIANG Tao,WANG Shuai.Removal of magnesium and calcium from electric furnace titanium slag by H3PO4oxidation roasting–leaching process [J].Transactions of Nonferrous Metals Society of China, 2018,28(2):356−366.[8]WANG Shuai,GUO Yu-feng,JIANG Tao,CHEN Feng,ZHENG Fu-qiang,TANG Min-jun,YANG Ling-zhi,QIU Guan-zhou,Appropriate titanium slag composition during smelting of vanadium titanomagnetite metallized pellets[J].Transactions of Nonferrous Metals Society of China,2018, 28(12):2528−2537.[9]TANG Wei-dong,YANG Song-tao,XUE Xiang-xin.Effectof B2O3addition on oxidation induration and reduction swelling behavior of chromium-bearing vanadium titanomagnetite pellets with simulated coke oven gas[J].Transactions of Nonferrous Metals Society of China,2019, 29(7):1549−1559.[10]ZHENG Fu-qiang,CHEN Feng,GUO Yu-feng,JIANG Tao,TRAVYANOV A Y,QIU Guan-zhou.Kinetics of hydrochloric acid leaching of titanium from titanium-bearing electric furnace slag[J].JOM,2016,68(5):1476−1484. [11]SONG Wen-chen,LI Hong,ZHU Fu-xing,LI Kun,ZHENGQuan,LI Hong.Extraction of vanadium from molten vanadium bearing slag by oxidation with pure oxygen in the presence of CaO[J].Transactions of Nonferrous Metals Society of China,2014,24(8):2687−2694.[12]PENG Xue-feng,ZHANG Yang,FAN Bing-qiang,ZHENGShi-li,WANG Xiao-jian,ZHANG Ying,LI Ping,LIU plexation separation for vanadium and chromium by dithiocarbamate and its application in treatment of chromium-vanadium-bearing slag[J].Transactions of Nonferrous Metals Society of China,2019, 29(11):2400−2410.[13]LI Wei,FU Gui-qin,CHU Man-sheng,ZHU Miao-yong.Influence of V2O5content on the gas-based direct reduction of hongge vanadium titanomagnetite pellets with simulated shaft furnace gases[J].JOM,2018,70(1):76−80.[14]INOUE R,SUITO H.Distribution of vanadium betweenliquid iron and magnesium oxide-saturated slags of the calcium oxide−magnesium oxide−iron oxides−silicon dioxide system[J].Transaction Iron Steel Institute Japan, 1982,22:705−714.[15]LIU Xuan,DIAO Jiang,KE Zhao-qun,QIAO Yong,ZHANG Tao,XIE Bing.Experimental investigation and thermodynamic modeling of vanadium,chromium and phosphorus distributions between FeO−SiO2−CaO−V2O3−Cr2O3−P2O5−MnO slag and semi-steel[J].Metallurgical Research&Technology,2016,113(4):407−419.[16]JUNG W G,KIM H S,CHUNG S Y,CHOI H S.Equilibrium of vanadium between molten iron and CaO−SiO2−MgOsat.−FetO slag[J].Steel GRIPS,2003, 1:361−366.[17]SHIN D Y,WEE C H,KIM M S,YOU B D,HAN J W,CHOI S O,YUN D J.Distribution behavior of vanadium and phosphorus between slag and molten steel[J].Metals and Materials International,2007,13(2):171−176.[18]DONG Jin-ming,ZHAO Fei,ZHANG Yan-ling,QIUSheng-tao,GAN Yong.Distribution behaviors of vanadium between hot metal and FeO−SiO2−MnO(−TiO2)slag systemand influential factors[J].The Chinese Journal of ProcessEngineering,2010,10(6):1076−1083.(in Chinese)[19]ZHANG Y L,ZHAO F,WANG Y G.Effects of influencingfactors on distribution behaviors of vanadium between hotmetal and FeO−SiO2−MnO(−TiO2)slag system[J].SteelResearch International,2011,82(8):940−950.[20]WRIGHT S,DAVIDSON R.Distribution of vanadiumbetween Al2O3−CaO−MgO−SiO2−TiO2slag and carbonsaturated iron[J].Mineral Processing and ExtractiveMetallurgy,2019..doi/full/10.1080/25726641.2019.1633505.[21]YAN Jia-rong,XIE Bing,ZENG Xiao-yi,HUANG Qing-yun,LI Hong-yi.Vanadium distribution between blast furnaceslag and hot metal[C]//4th International Symposium onHigh-Temperature Metallurgical Processing.San Antonio,Texas,USA:TMS,2013:333−339.[22]HUANG Shi-hong,LEI Ting,HAN Feng-xia,ZHOU Lin.Element distribution of titanium slag smelted by DC arcfurnace[J].Journal of Rare Metal,2014,38:283−289.(inChinese)[23]WANG Zhen-yang,ZHANG Jian-liang,XING Xiang-dong,LIU Zheng-jian.Distribution behaviors and thermodynamicanalysis of vanadium between molten iron and high titaniumslag[J].The Chinese Journal of Nonferrous Metals,2015,25: 1355−1361.(in Chinese)[24]YANG Su-bo,LUO Ze-zhong,CAI Kai-ke,JIANG Jun-pu,SONG Bo.Thermodynamic study on distribution ofvanadium between iron melt and slag in basic oxygenfurnace[J].Iron Steel,2006,41:36−38.(in Chinese) [25]NAN Xiang-min.Study on vanadium oxide reduction inblast furnace hearth[J].Zhuzao Jishu,2013,34:193−195.(in Chinese)[26]LIU Tian-zhong,WANG ponent distributionbetween carbon saturation molten iron and molten slag[J].Iron Steel Vanadium Titanium,1991,12:1−4.(in Chinese) [27]BALE C W,BÉLISLE E,CHARTRAND P,DECTEROV SA,ERIKSSON G,GHERIBI A E,HACK K,JUNG I H, KANG Y B,MELANÇON J,PELTON A D.FactSage thermochemical software and databases,2010−2016[J].Calphad,2016,54:35−53.[28]HUANG Xi-hu.Iron and steel metallurgy principle[M].4thed.Beijing:Metallurgical Industry Press,2013.(in Chinese) [29]ZHANG Sheng-fu,ZHANG Xi,LIU Wei,LV Xue-wei,BAIChen-guang,WANG Long.Relationship between structureand viscosity of CaO−SiO2−Al2O3−MgO−TiO2slag[J].Journal of Non-Crystalline Solids,2014,402:214−222. 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小学下册G卷英语第1单元全练全测(有答案)
小学下册英语第1单元全练全测(有答案)英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.The giraffe's long neck helps it reach ______ (树叶).2.Magnesium burns in oxygen to produce _____ (magnesium oxide).3. A ______ is a geological feature that can provide habitat.4.The Earth's magnetic field protects us from ______.5.What do you call a baby cat?A. PuppyB. KittenC. CalfD. Chick答案:B6.Which animal is known for its shells?A. FishB. TurtleC. LionD. Dog答案:B7.The man has a funny ________.8.The chemical formula for calcium chloride is _______.9.The __________ is known for its beautiful beaches. (加勒比海)10.How many months have 30 days?A. 4B. 5C. 6D. 7答案: A11.Certain plants can _____ (繁殖) quickly in warm weather.12.My toy ____ can swim in the pool! (玩具名称)13.The ______ is a common houseplant that needs a lot of sunlight. (这是一种常见的室内植物，需要很多阳光。
以贝壳和海水作为原料生产镁的流程
Ever wondered how we get magnesium from seashells and seawater? It's a pretty wild process, let me tell you! First, we scoop up a bunch of seashells and get them ready for the big transformation. These shells are packed with calcium carbonate, which we can magically turn into magnesium oxide through some fancy chemical reactions. After we clean and crush the shells, it's time for the real fun to begin. We heat up the crushed shells with a special ingredient called ferrosilicon in a super hot furnace. As the shells react with the ferrosilicon, they start to release magnesium vapor, which we then cool down to form actual magnesium metal. It's like a science experiment straight out of a mad scientist's lab, but hey, it works like a charm! Who knew seashells could be so cool, right?有没有想过我们如何从海贝和海水中获取镁？这是一个相当疯狂的过程，让我告诉你！我们挖出一堆海贝让他们准备好大变换。
小学上册T卷英语第五单元期末试卷(有答案)
小学上册英语第五单元期末试卷(有答案)英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1. The boiling point of water is _______ degrees Celsius.2.I can _____ to the top of the slide. (climb)3.My friend is a ______. He enjoys making videos.4.We need to _______ (提高) our skills.5.What is the term for a baby kangaroo?A. JoeyB. CubC. KidD. Lamb答案: A6.We can _______ (一起) explore the forest.7.What is the name of the famous mountain range in North America?A. AndesB. RockiesC. AppalachianD. Sierra Nevada答案:B.Rockies8.The ________ loves to explore and find treasures.9.He is flying a ___. (kite)10. A cat nuzzles against your ________________ (手).11.What do we call the process of light bending as it passes through different mediums?A. ReflectionB. RefractionC. DiffractionD. Absorption答案:B12.We should _____ (clean/dirty) the room.13.I will _____ (help/helped) you with your homework.14.My favorite game involves a ________.15.What is the primary color of the sky on a clear day?A. BlueB. WhiteC. GrayD. Black答案: A16.She is ___ (cooking/cleaning) the kitchen.17.My aunt is a __________ (心理医生).18.What do you call a story that is not true?A. FactB. LegendC. MythD. Fiction答案:D.Fiction19.We drink ________ (water) when we are thirsty.20.The soup is _______ (cooking) on the stove.21.What is the name of the famous desert located in Northern Africa?A. Gobi DesertB. Sahara DesertC. Kalahari DesertD. Arabian Desert 答案:B.Sahara Desert22.The Earth's crust is essential for sustaining ______.23.The ______ (狮子) lives in Africa and is very strong.24._____ (kelp) is a type of sea plant.25.The rabbit hops around the _______ (花园).26.The __________ is the capital city of Japan. (东京)27.I see a _____ (deer) in the forest.28.The ancient Romans believed in many _______. (神灵)29. A _______ can be used to demonstrate the principles of optics.30.My family enjoys __________ during the holidays, especially __________.31. A thermometer measures ______ temperature.32.Objects that float in water are ______ than water.33.We use _____ to measure temperature.34.I like to play with my toy ________ (玩具名称) at the beach.35.I have a collection of toy ______ (恐龙). They are colorful and ______ (有趣的) to play with.36.It is ______ (下雨) outside, so take an umbrella.37.The ______ helps protect the body from injury.38.The capital of Italy is ________.39.My aunt is a ______. She loves to travel.40.__________ are substances that can conduct electricity when dissolved in water.41. A chemical reaction can involve the transfer of _____.42.What do you call a person who studies botany?A. BotanistB. HorticulturistC. FloristD. Gardener答案: A43.What do we call a scientist who studies the structure and function of biological molecules?A. BiochemistB. BiologistC. ChemistD. Geneticist答案: A44.I feel sleepy when it’s ______ (阴暗的) outside.45.The playground has a big ________.46.Where do birds live?A. CaveB. NestC. HouseD. Tree答案: B47.The _____ (气候变化) affects plant distributions globally.48.The Earth's rotation causes the cycle of day and ______.49.My sister and I have fun ____.50.The __________ is a famous destination for relaxation.51.The candy is ___ (sour).52.The chemical formula for propane is ______.53.We visit the ______ (植物园) for educational tours.54.The ____ has a beautiful song and sings in the morning.55.The ostrich cannot ______ (飞).56.She is wearing a beautiful ___. (dress)57.We are _____ (going/coming) home now.58.The __________ is a famous mountain located in the Swiss Alps. (马特洪峰)59.The _____ (蜗牛) leaves a trail as it moves slowly.60.__________ are often found in cleaning products for their effectiveness.61.Many plants have ______ (防御机制) against herbivores.62. A _____ (植物图鉴) can help identify local flora.63.The _____ (sandcastle) is tall.64.My cat loves to _______ (探索) the house.65.The river is _______ (清澈的).66.The _____ (starfish) is unique.67.The _____ (小鸟) builds a nest in the tree branches. 小鸟在树枝上筑巢。
小学上册第1次英语第3单元寒假试卷
小学上册英语第3单元寒假试卷英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.What is the capital of the Republic of the Congo?A. BrazzavilleB. Pointe-NoireC. DolisieD. NkayiA2.city) is a large area where many people live. The ____3.The process of melting occurs when a solid becomes a _______.4.My toy robot can _______ (我的玩具机器人可以_______).5.What is the name of the famous scientist known for his contributions to chemistry?A. Antoine LavoisierB. Dmitri MendeleevC. Robert BoyleD. Marie CurieA6.The sun is _______ (shining) through the trees.7.The _____ (刺猬) curls up when scared.8.I see a ___ (car/truck) on the road.9.My ________ (玩具名称) is the best gift I've ever received.10. A ____(community development) focuses on improving living conditions.11.Which of these is a type of cloud?A. CumulusB. MountainC. OceanD. ForestA12.What is the name of the famous desert located in Northern Africa?A. Gobi DesertB. Sahara DesertC. Kalahari DesertD. Arabian DesertB Sahara Desert13.She is ______ to school by bus. (going)14.The dog loves to ______ (run) in the yard.15.An exothermic reaction releases ______ into the surroundings.16.The fish swims _____ (fast/slow) in the water.17.The _____ (狐狸) is known for its cunning nature.18.I like to play _______ (棋) with my friends.19.What is the sound of a sheep?A. MeowB. BarkC. BaaD. MooC20.The _______ of light can create different colors when passed through a prism.21. A _______ can help to demonstrate the principles of energy conservation in a system.22.My sister wants a pet ______ (小鸟) that can sing.23.Which animal is known for its ability to change colors?A. ChameleonB. DogC. CatD. RabbitA24.I enjoy ___ (playing) with my little brother.25.My favorite video game is _______ (《超级马里奥》).26.The girl enjoys ________.27.What is the opposite of empty?A. FullB. LightC. HeavyD. Small28. (American) Revolution inspired other countries to seek freedom. The ____29.When I travel, I take a small ________ (毯子) and pillow for comfort.30.What do we call a scientist who studies the atmosphere?A. MeteorologistB. GeologistC. ChemistD. BiologistA31.The _______ changes color in the fall.32.Dolphins are known for their ______ behavior.33.What do you call the story of someone's life?A. BiographyB. NovelC. PoemD. ArticleA34.I want to ________ a new toy.35.What do you call a baby lemur?A. KitB. PupC. CalfD. Cub36.The dolphin sings songs in the _________. (水下)37.The country famous for its music is ________ (阿根廷).38.The ______ helps us to stay balanced.39.What is the main ingredient in sushi?A. PastaB. RiceC. BreadD. MeatB40.I want to learn ________ (新语言).41.I like to _______ (play) outside.42.The ice cream is _____ melting. (slowly)43.In a chemical reaction, substances change into new __________.44.The finch is a small _______ (鸟) that sings beautifully.45.What do we call the process of a seed growing into a plant?A. GerminationB. PollinationC. FertilizationD. PhotosynthesisA46.What is the opposite of big?A. LargeB. SmallC. TallD. Wide47. A ______ can live in very cold climates.48.What do we call the process by which plants absorb carbon dioxide?A. PhotosynthesisB. RespirationC. TranspirationD. DigestionA49.In a chemical reaction, reactants are transformed into _______.50. A ________ is a high area of land that is flat on top.51. A _____ (兔子) can hop very fast.52.The owl has excellent ______ (听力).53.I enjoy _____ (listening/reading) to music.54.How many players are on a soccer team?A. FiveB. SixC. SevenD. Eleven55.What is the name of the process by which plants release water vapor?A. CondensationB. EvaporationC. TranspirationD. Sublimation答案:C56.What type of animal is a snake?A. MammalB. ReptileC. BirdD. FishB57.The ________ (生态恢复计划) can revive habitats.58.The first successful vaccine for polio was developed by ________ (萨尔克).59.What is the name of the largest desert in the world?A. SaharaB. GobiC. KalahariD. ArabianA Sahara60. A solar flare can disrupt communications on Earth and in ______.61.What is the term for the study of insects?A. EntomologyB. OrnithologyC. ZoologyD. BotanyA62.The chemical formula for magnesium sulfate is ______.63.What is the process of growing seeds into plants called?A. GerminationB. FertilizationC. PhotosynthesisD. PollinationA64. A __________ is a natural reservoir of water.65.What do you call a person who writes stories?A. AuthorB. EditorC. JournalistD. PoetA66.ts are __________ (有毒的) and should be handled carefully. Some pla67.My sister is a ______. She loves to help in the community.68.What do you call the place where you learn?A. HomeB. SchoolC. OfficeD. StoreB69.Certain plants can ______ (帮助) mitigate climate change.70.I want to be a ________ (艺术家) when I grow up.71.My sister's _____ is purple and yellow.72.What do we call a large body of fresh water?A. OceanB. RiverC. LakeD. Sea73.We play _____ (乒乓球) after school.74.Hydrogen bonds play a crucial role in the properties of ______.75.What is the main purpose of a map?A. To tell timeB. To show directionsC. To tell storiesD. To display pictures76.We went to the ______ for a field trip. (museum)77.n War started in _______. (1950年) The Loui78.The _______ (Plymouth Rock) is a symbol of the Pilgrims’ landing in America.79.The _______ can thrive in moist environments.80. Age is known as the first period in human __________. (历史) The Ston81.The ________ was a famous queen of ancient Egypt.82.Which day comes after Monday?A. SundayB. TuesdayC. WednesdayD. Thursday83.I saw a _____ (小猫) sleeping in a sunny spot.84. A _____ (plumeria) tree smells lovely.85.What is the largest organ in the human body?A. HeartB. LiverC. SkinD. Brain86.What is the capital of Indonesia?A. JakartaB. BaliC. SurabayaD. BandungA87.The chemical formula for ethanol is ________.88.My aunt loves __________ (参与文艺活动).89.My grandma enjoys playing ____ (puzzles).90.My pet ______ (狗) loves to fetch sticks.91.The owl's feathers are very ______ (柔软).92.What color is the sun?A. BlueB. YellowC. GreenD. Red93.The _____ (flower/tree) is blooming.94.What do we call the process of growing plants?A. GardeningB. FarmingC. AgricultureD. All of the above95.What do bees collect from flowers?A. NectarB. PollenC. WaterD. Seeds96.We have a ______ (有趣的) day planned for next month.97. A ________ can hide in its shell.98.I enjoy riding my ______ (自行车) in the neighborhood after school.99.__________ (化学反应) can release or absorb energy.100.I love my _____ (玩具兵).。
小学下册C卷英语第4单元综合卷
小学下册英语第4单元综合卷英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.I see a _______ (ladybug) on a leaf.2.我的朋友喜欢 _______ (活动). 她觉得这很 _______ (形容词)3.The capital of Belgium is __________.4.What is the name of the famous painting by Leonardo da Vinci?A. The Starry NightB. The Last SupperC. The Mona LisaD. Girl witha Pearl Earring5.Solar panels convert sunlight into electrical ______.6.Which fruit is red?A. BananaB. OrangeC. AppleD. Grape7.What do we call the process of cooking food using dry heat?A. BoilingB. BakingC. FryingD. SteamingB8.What is the name of the toy that spins on the ground?A. FrisbeeB. TopC. Yo-yoD. Kite9._____ (根系) support the plant and absorb nutrients.10.The chemical formula for potassium chromate is ______.11.I can play pretend with my ________ (玩具名称).12.What do we call the outer layer of the Earth?A. CoreB. MantleC. CrustD. Bedrock13.I have a close _____ (堂姐).14.The bat hangs upside down in the ____.15.h Revolution began in __________ (1789年). The Fren16.The _______ of an object can be tested using a calibrated scale.17.I like to ______ (参与) in community projects.18.The bear prepares for _____ winter.19.The children are ________ in the playground.20.古代的________ (stories) 反映了人们的信仰和理想。
小学下册A卷英语第1单元自测题[含答案]
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小学下册英语第1单元自测题[含答案]英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.We will go ________ (海边) this summer.2.What is the main language spoken in Spain?A. FrenchB. ItalianC. SpanishD. Portuguese答案:C3.I enjoy playing ______ (桌游) with my f amily on rainy days. It’s a fun way to bond and laugh together.4.The deer hides in the ______ (树林). It is very ______ (小心).5.What sound does a dog make?A. MeowB. MooC. BarkD. Quack6.Which season comes after spring?A. WinterB. SummerC. FallD. Autumn7.Australia is known for its _______ animals.8.I enjoy playing chess because it challenges my __________.9.The butterfly starts as a _______ before it becomes an adult.10.The cake has ___ candles. (five)11.The chemical symbol for yttrium is __________.12.What do we call a group of stars that form a recognizable pattern?A. Solar SystemB. GalaxyC. ConstellationD. Nebula答案:C Constellation13.What is the capital of Japan?A. BeijingB. SeoulC. TokyoD. Bangkok14.How many colors are in a rainbow?A. FiveB. SixC. SevenD. Eight15.The Earth's surface is shaped by both ______ and geological processes.16.My sister loves to ________ stories.17. A ______ occurs when a substance is heated and changes form.18.What do we call the study of the universe?A. BiologyB. AstronomyC. ChemistryD. Physics答案:B19. A penguin waddles on the _______ and swims.20.The _______ can be a wonderful subject for photography.21.The _______ helps nourish the soil.22.The __________ (历史的文化影响) shape identities.23.How many Earth days does it take for Venus to rotate once on its axis?A. 30B. 243C. 365D. 1524.The teacher _____ us to be quiet. (reminds)25.My favorite subject in school is ________ (数学). I like solving problems and playing with ________ (数字).26.What color is the sky on a clear day?A. GreenB. BlueC. RedD. Yellow答案:B27.The chemical formula for magnesium hydroxide is ______.28.What do bees produce?A. MilkB. HoneyC. EggsD. Butter答案:B29. A saturated solution contains the maximum amount of _______ that can dissolve.30.What is the tallest mountain in the world?A. K2B. KangchenjungaC. Mount EverestD. Kilimanjaro答案:C Mount Everest31.ts can grow in ______, while others prefer dry soil. (有些植物可以在潮湿的环境中生长，而另一些则喜欢干燥的土壤。
基于热力学分析的MAP法处理模拟氮磷废水研究
基于热力学分析的MAP法处理模拟氮磷废水研究米海蓉;成功;李士松;刘桂芳;丁学姣【摘要】磷酸氨镁（MAP）法处理氮磷废水过程中，NH4＋－N和PO43－－P 的去除率无法反映影响MAP法的因素及沉淀物的生成过程。
为解决此问题通过单因素实验以及热力学平衡计算的方法，对MAP法处理模拟氮磷废水中的氨氮和磷酸盐的影响因素进行了分析和探讨。
研究了初始氨氮浓度、pH值、摩尔比n （ Mg）∶ n（ N）以及摩尔比n（P）∶ n（N）条件，对NH4＋－N和PO43－－P去除率的影响以及不同条件各沉淀组分的变化。
结果表明，在pH值为9～9．5，摩尔比n（Mg）∶ n（N）∶ n（P）为1∶1∶1条件下，MAP法的处理效果最优，NH4＋－N去除率可达79．35％～93．76％，PO43－－P去除率可达86．76％～95．43％，且MAP沉淀物中杂质较少；虽然增大摩尔比n（ Mg）∶ n（ N）或摩尔比n（P）∶ n（N）会分别提高PO43－－P和NH4＋－N去除率，但也会分别使NH4＋－N和PO43－－P残余量增大。
%In the nitrogen and phosphorus wastewater treatment with magnesium ammonium phosphate ( MAP ) process, the removal rate of NH4+-N and PO4 3–-P cannot reflect the influencing factors of the MAP process or the sediment generation process. To solve this problem, this paper analyzes the influential factors of ammonia nitrogen and phosphate in the nitrogen and phosphorus wastewater using a single factor experiment and the method of ther⁃modynamic equilibrium calculation. The variance of ammonia nitrogen and phosphate removal are analyzed together with precipitation generation at different pH values using the mole ratios ofn(Mg) ∶ n(N) and n(P) ∶ n(N). Re⁃sults demonstrate that the optimaloperating condition for the MAP process is at a pH in the range of 9~9.5 and at a Mg ∶ N ∶ P molar ratio of 1 ∶ 1 ∶ 1. Under these conditions, the removal rate of NH4+-N and PO4 3–-P are 79.35%~93.76% and86.76%~95.43%, respectively, thereby delivering the highest purity of MAP. Increasing the molar ratio n(Mg) ∶ n(N) or n(P) ∶ n(N) im proves the removal rate of PO43–-P and NH4+-N, respective⁃ly, but also results in greater amounts of remaining NH4+-N and PO43–-P, respectively.【期刊名称】《哈尔滨工程大学学报》【年(卷),期】2016(037)011【总页数】6页(P1514-1519)【关键词】磷酸氨镁;氮磷废水;热力学平衡;影响因素;摩尔比;去除率【作者】米海蓉;成功;李士松;刘桂芳;丁学姣【作者单位】哈尔滨工程大学航天与建筑工程学院，黑龙江哈尔滨150001;哈尔滨工程大学航天与建筑工程学院，黑龙江哈尔滨150001;哈尔滨工程大学航天与建筑工程学院，黑龙江哈尔滨150001;哈尔滨工程大学航天与建筑工程学院，黑龙江哈尔滨150001;哈尔滨工程大学航天与建筑工程学院，黑龙江哈尔滨150001【正文语种】中文【中图分类】X703.1磷酸铵镁(magnesium ammonium phosphate，MAP)，俗称鸟粪石，常以六水结晶化合物MgNH4PO4·6H2O形式存在，为白色无机晶体矿物，相对密度为1.711，相对分子量为245.41，溶度积为2.510-13，微溶于冷水，在碱溶液中分解[1]。
三杯茶的英文介绍
Withering technique: flexibly control the withering time and spreading thickness based on the tenderness of fresh leaves and weather conditions, to avoid excessive withering leading to insufficient tea fermentation or the production of odors.Green killing technique: Control the temperature and time of green killing to avoid tea leaves being burnt or fermented excessively due to excessive temperature or time. At the same time, it is necessary to keep the green leaves evenly heated and avoid local overheating.Rubbing technique: When rolling, the principle of light pressure, slow rolling, and short time should be mastered to make the tea leaves form a rope shape and remain intact. Excessive kneading can cause tea leaves to break and the soup color to become cloudy.Drying technique: During drying, temperature and time should be controlled to avoid tea leaves becoming burnt or losing their aroma due to excessive temperature or time. At the same time, it is necessary to keep the tea evenly heated and dehumidified, ensuring consistent drying effects.
关于化学实验的英文作文
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