Mullite whiskers derived from kaolin

高三测试题制作美式烤猪颈肉配芒果酱英语作文Title: "Creating a High School Test: Making Americanstyle Grilled Pork Neck with Mango Sauce"As a high school teacher, I believe in engaging my students in practical learning experiences that extend beyond the confines of textbooks and exams. One such innovative approach I have decided to undertake is the creation of a high school test with a delicious twist the task of making Americanstyle grilled pork neck with mango sauce.The rationale behind this unique test format is to merge academic knowledge with realworld skills, fostering creativity, teamwork, and problemsolving abilities among students. By incorporating a handson cooking task into the testing framework, I aim to provide students with a holistic learning experience that goes beyond traditional assessment methods.To kick off the test preparation process, students will be introduced to the recipe for Americanstyle grilled pork neck with mango sauce. This will involve a stepbystep guide outlining the ingredients required, the cooking techniques involved, and the overall presentation of the dish. Additionally, studentswill be briefed on the cultural significance of the dish, highlighting its origins and popularity in American cuisine.Next, students will be divided into groups, each tasked with preparing the dish within a specified time frame. This groupbased approach is designed to promote collaboration, communication, and time management skills among students, mirroring reallife scenarios where teamwork is essential for success.During the test, students will be required to demonstrate their culinary skills by following the recipe instructions accurately, ensuring that the dish is cooked to perfection. They will also be evaluated on their creativity in presenting the grilled pork neck with mango sauce, taking into consideration factors such as plating, garnishing, and overall visual appeal.In addition to the practical cooking component, students will also be asked to reflect on their learning experience in a written assignment. This reflection will prompt students to articulate their thoughts on the test format, their individual contributions to the group task, and the lessons they have learned throughout the process.By incorporating a handson cooking task into the high school test format, I aim to provide students with a memorable and enriching learning experience that combines academic rigor with practical skills development. Through this innovative approach, I hope to inspire students to think outside the box, embrace newchallenges, and discover the joy of learning through experiential activities.。

高考英语外刊阅读理解训练——老干妈等辣椒酱是怎样成为世界时尚美食的？——改编自World in a dishSome like it hot The rise of chilli crisp is a case study in how foods become fadsDuring lockdowns, some people found joy in cooking intricate meals that were previously impossible to make due to the rush of ordinary life. However, others found making three meals a day tedious, especially if they were cooking for small children. Enter condiments –a simple way to satisfy both groups. Condiments offered enthusiasts a chance to make dips and drizzles typically found at local delis and provided weary cooks with an easy way to add flavor to mundane meals, such as cheese toasties. Chilli crisp, a sauce made from garlic, shallots, fermented black beans, sesame seeds, and chili pepper oil, became increasingly popular during the pandemic because it satisfies humans' love of crispy and spicy foods.In China, chilli crisp has been a beloved condiment for centuries. The most famous brand is Lao Gan Ma, created by Tao Huabi in the southwestern province of Guizhou. Tao started selling noodles coated with the sauce in 1989 and now produces 13 million bottles of the condiment every day. During the pandemic, chilli crisp's popularity spread globally as people began cooking more at home and sharing theircreations on social media.Kevan Vetter of McCormick’s Flavour Forecast notes that tastemakers previously learned about new food trends by visiting restaurants and interviewing chefs, but during lockdowns, they turned to social media to see what home cooks and professional chefs were making. Along with banana bread, chilli crisp was one of the top trending foods during the pandemic, and its popularity has not waned.Despite its popularity, the question remains whether amateurs will continue making chilli crisp or turn to mass-produced alternatives. People rarely bother making ketchup because the commercial versions meet their taste preferences, so Tao Huabi might argue that her company's commercial option is just as authentic. With the growing East Asian population in America and Britain, and numerous new brands of chilli crisp emerging, it is likely to become a pantry staple, much like salsa once seemed exotic but is now commonly found in households.【重点词汇】1. lockdowns ['lɒkdaʊnz] n. 封锁期2. intricate ['ɪntrɪkət] adj. 复杂的, 难理解的3. rush [rʌʃ] n. 匆忙, 繁忙；v. 冲, 快速移动4. ordinary ['ɔːdəneri] adj. 普通的；n. 平凡的人5. tedious ['tiːdiəs] adj. 乏味的, 枯燥的6. condiments ['kɑːndɪmənts] n. 调味品7. satisfy ['sætɪsfaɪ] v. 满足, 符合8. enthusiasts [ɪn'tjuːziæsts] n. 热衷者, 爱好者9. dips [dɪps] n. 浸泡；v. 把...浸入（液体中）10. drizzles ['drɪzlz] n. 涓涓细流；v. 淋雨11. delis ['deliz] n. 熟食店12. weary ['wɪri] adj. 疲惫的；v. 使疲劳13. add [æd] v. 添加, 增加14. flavor ['fleɪvə] n. 味道, 风味15. mundane ['mʌndeɪn] adj. 平凡的, 世俗的16. cheese [tʃiːz] n. 奶酪17. toasties ['təʊstis] n. 烤面包片，夹馅烤制而成的小饼干或小烤面包; adj. 烤得脆的18. Chilli ['tʃɪli] n. 带辣椒的食品；adj. 辣的19. crisp [krɪsp] adj. 脆的；n. 薯片；v.（使）变脆20. sauce [sɔːs] n. 酱汁21. garlic ['ɡɑːlɪk] n. 大蒜22. shallots ['ʃæləts] n. 葱头23. fermented ['fɜːmɛntɪd] adj. 发酵的24. black beans 黑豆25. sesame seeds ['sesəmi siːdz] 芝麻籽26. chili pepper ['tʃɪlɪˈpɛpər] 红辣椒27. increasingly [ɪn'kriːsɪŋlɪ] adv. 不断增加地28. beloved [bɪ'lʌvd] adj. 深受喜爱的, 心爱的29. brand [brænd ] n. 品牌30. created [kri:ˈeɪtɪd] v. 创造, 制造31. southwestern ['sʌθˈwɛstən] adj. 南西的，位于西南方向的32. province [ˈprɒvɪns] n. 省份33. selling ['selɪŋ] v. 出售34. noodles ['nuːdlz] n. 面条35. coated [kəʊtd] adj. 有衣服, 涂层；v. 包裹, 覆盖, 涂上36. produces [prə'dju:sɪz] v. 生产, 制造37. bottles ['bɒtlz] n. 瓶子38. pandemic ['pændemɪk] adj. 大范围流行的；n. 大流行病39. spread [spred] v. 扩散, 传播40. globally ['ɡləʊbli] adv. 全球地41. cooking ['kʊkɪŋ] v. 烹调, 做饭42. creations [kri'eɪʃ(ə)n] n. 创作物；创造43. social media ['soʊʃl 'midiə] 社交媒体44. tastemakers ['teɪs teɪməkərz] n. 潮流先锋, 匠人45. previously ['priːviəsli] adv. 先前, 以前46. turned [təːnd] v. 转向；变成；转身47. see [siː] v. 看见, 查看48. professional [prə'feʃ(ə)n(al)] adj. 专业的，职业的49. waned [weɪnd] v. 减少，衰退50. mass-produced ['mæsprə'dju:st] 大量生产的【阅读理解练习题】1. What is the main idea of this article?A. The popularity of chilli crisp has skyrocketed during the pandemic due to its versatility and flavor enhancement.B. Making meals during lockdown was challenging, but condiments like chilli crisp provided a simple and delicious solution.C. T ao Huabi is the creator of the beloved Chinese condiment, Lao Gan Ma, which has been popular for centuries.D. Social media played a significant role in the spread of chilli crisp's popularity during lockdowns.答案：A。

高二测试题制作希腊风味烤鸡配柠檬英语作文In today's fastpaced world, it's important to appreciate the beauty of simplicity and authenticity in our lives. One way todo this is through the joy of cooking and savoring a delicious meal that not only nourishes our bodies but also feeds our souls. In this essay, we will explore the art of making Greekstyle roasted chicken with lemon, a dish that embodies the essence of Mediterranean cuisine and brings a taste of Greece to your table.To begin, gather the necessary ingredients for this flavorful dish. You will need a whole chicken, olive oil, garlic, fresh herbs such as oregano and thyme, salt, pepper, and of course, lemons. The key to the success of this recipe lies in thequality of the ingredients, so be sure to select the freshest produce available.Start by preheating your oven to the appropriate temperature. While the oven is heating up, rinse the chicken thoroughly under cold water and pat it dry with paper towels. Next, place the chicken in a roasting pan and generously rub it with olive oil, ensuring that the entire surface is coated. This will help the skin crisp up beautifully during the cooking process.Now it's time to season the chicken. Crush a few cloves of garlic and sprinkle them over the chicken, along with the fresh herbs, salt, and pepper. Slice a couple of lemons and place them inside the cavity of the chicken, along with a few sprigs ofherbs for extra flavor. The lemon not only infuses the meat with a bright, citrusy aroma but also helps keep the chicken moist as it roasts.Once the chicken is seasoned to perfection, cover the roasting pan with foil and place it in the oven. Allow the chicken to roast for the appropriate amount of time, basting it occasionally with the pan juices to ensure that it stays moist and flavorful. The aroma of roasted chicken and citrusy lemons will soon fill your kitchen, whetting your appetite for the delicious meal to come.As the chicken cooks, take this time to prepare some side dishes to complement the main course. A simple Greek salad with fresh vegetables, feta cheese, olives, and a drizzle of oliveoil is the perfect accompaniment to the roasted chicken. You can also whip up some tzatziki sauce using Greek yogurt, cucumber, garlic, and dill for a cool and refreshing contrast to the warm, savory chicken.Finally, once the chicken is golden brown and cooked through, remove it from the oven and let it rest for a few minutes before carving. The tender meat, infused with the flavors of garlic, herbs, and lemon, will practically melt in your mouth,delighting your taste buds with every bite.In conclusion, the art of making Greekstyle roasted chicken with lemon is a culinary journey that brings the flavors of theMediterranean to your home. By embracing simple yet highquality ingredients and traditional cooking techniques, you can create a meal that not only nourishes your body but also transports you to the sunkissed shores of Greece with every bite. So next time you're in the mood for a taste of the Mediterranean, why not try your hand at making this delightful dish and savor the magic of Greek cuisine?。

2024届高考备考外刊精选精读二Why do we eat spicy food我们为什么喜欢吃辣？文本导读：虽然辛辣食物会刺激口内黏膜，让人舌头发麻、嘴巴冒火，浑身冒汗，但很多人认为吃辣是“痛并快乐的”，甚至“无辣不欢”。

辣椒是世界各地许多菜肴中的关键成分。

本文从科学和历史两方面分析人们热衷吃辣的原因。

Step 1:词汇温习go numb 发麻taste 味道sour 酸的bitter 苦的sensation 感觉trigger 引发，触发chemical compound 化合物contain 含有temper 使缓和release 释放endorphin 内啡肽conscious 有意的rational being 理性的动物derive 获得，得到thrill-seeking 寻求刺激的develop a taste for 养成吃…的习惯cultivate 种植intervention 干预content 含量going strong 依旧强烈Step 2:原文精听+精读You know the feeling – your ears start to warm up, your tongue goesnumb, you start sweating and taking deep breaths. You've just eaten something spicy knowing it would be painful, and, yet, you chose to do it anyway. Are humans just masochistic, or is there something else going on? The answer lies in both science and history.Let's start with the science. Spicy isn't actually a taste like salty, sweet, sour and bitter – it’s a sensation. This sensation is triggered by a chemical compound found in chilli peppers called 'capsaicin'. When we eat foods containing capsaicin, our bodies are tricked into thinking the temperature is actually rising. In trying to temper the burning sensation, our bodies release endorphins which control pain and, at the same time, give a feeling of pleasure – like painkillers.This is what is happening chemically, but there is also a conscious side to choosing spicy food. Dr Tamara Rosenbaum, Cognitive Neuroscientist at the National Autonomous University of Mexico, explains in an interview with the BBC that this is because we are rational beings – we know that the burning sensation of chilli does not physically harm us. Furthermore, we derive pleasure from the other ingredients chilli is generally cooked and eaten with – including fat, sugar and salt. So – like skydiving – eating chilli is a form of thrill-seeking or 'benign masochism', where we get pleasure from a seemingly negative sensation.This masochistic relationship with capsaicin has been a long one, starting in the Andes of South America, where chilli peppers originate.Humans were one of the few mammals on Earth that developed a taste for capsaicin so, archaeological evidence suggests, they started cultivating chilli peppers about six thousand years ago. Human intervention changed the chilli pepper to suit human tastes and needs – including the pepper's colour, size and capsaicin content – helping to explain the many different types of chilli peppers now available.Fast-forward to today, and our love affair with the chilli pepper is going strong. We eat around 57.3 million tons of peppers globally each year, and chilli is a key ingredient in traditional dishes from Mexico to Korea. Maybe we are masochistic after all.Step 3:阅读原文并回答以下问题。

非水解溶胶-凝胶法制备莫来石晶须江伟辉;彭永烽;刘健敏;冯果;谭训彦;于云【摘要】以正硅酸乙酯和无水氯化铝为前驱体,乙醚为氧供体,采用非水解溶胶-凝胶法制备了直径为0.2～20μm,长径比高达60～70的莫来石晶须.借助XRD、SEM和TEM等测试手段研究了莫来石干凝胶粉的活性、矿化剂氟化铝引入方式及其用量、成型压力以及煅烧温度等工艺参数对合成莫来石晶须的影响.结果表明:采用恒压回流工艺制备的莫来石干凝胶粉,在12MPa压力下压制成片状,以外置方式引入3wt%的氟化铝,在1200℃保温1h可制备质量较好的莫来石晶须.【期刊名称】《无机材料学报》【年(卷),期】2010(025)005【总页数】5页(P532-536)【关键词】非水解溶胶-凝胶法;莫来石;晶须;长径比【作者】江伟辉;彭永烽;刘健敏;冯果;谭训彦;于云【作者单位】景德镇陶瓷学院材料科学与工程学院,景德镇,333001;中国科学院上海硅酸盐研究所特种无机涂层重点实验室,上海,200050;景德镇陶瓷学院材料科学与工程学院,景德镇,333001;景德镇陶瓷学院材料科学与工程学院,景德镇,333001;景德镇陶瓷学院材料科学与工程学院,景德镇,333001;景德镇陶瓷学院材料科学与工程学院,景德镇,333001;中国科学院上海硅酸盐研究所特种无机涂层重点实验室,上海,200050【正文语种】中文【中图分类】TQ174莫来石晶须不仅具有耐高温、耐磨损、抗氧化等优良性能,而且还具有高温强度大、高温蠕变小、热膨胀较小和抗热震性好等特点[1],因此,它是一种优异的复合材料增强体,可以大幅度提高金属、聚合物以及陶瓷基复合材料的综合性能.不仅如此,与非氧化物晶须相比,它还能够在更高的温度和更恶劣的氧化条件下使用.目前,国内外合成莫来石晶须的方法主要有矿物分解法、熔盐法以及传统水解溶胶-凝胶法等.矿物分解法[2]直接采用粘土等矿物为原料,经高温煅烧,莫来石晶须从熔体中析出;熔盐法[3]主要是在莫来石前驱体中加入各种熔盐如 K2SO4,莫来石晶须于熔盐中析出.为了制备纯度较高的莫来石晶须,两者都要经过滤、洗涤和烘干等操作,工艺颇为复杂.而传统水解溶胶-凝胶法一般以硅的醇盐、铝的醇盐或铝的无机盐为前驱体,在制备的莫来石溶胶或干凝胶中加入生长矿化剂氟化物,如HF、AlF3等,在密闭的容器中煅烧而合成莫来石晶须.如 Okada等[4]以正硅酸乙酯和硝酸铝为原料,在制备的 A12O3-SiO2干凝胶中加入一定量的 AlF3,经 1100～1600℃密闭煅烧合成了长径比为 10～25的莫来石晶须.Is mail等[5]用相同的方法,用 HF代替了AlF3,经1400℃合成了长径比为 10～20的莫来石晶须.传统水解溶胶-凝胶法的不足之处在于合成莫来石的温度通常在1200℃以上,此时莫来石样品开始产生烧结,莫来石晶粒生长受到阻碍,制备的莫来石晶须长径比较小,不易合成高质量的莫来石晶须.与传统水解溶胶-凝胶法相比,非水解溶胶-凝胶技术具有工艺简单、制备周期短、晶须制备温度低等优势,但其溶胶-凝胶制备过程必须在干燥的环境中进行,否则会由于吸附环境中的水份而影响非水解缩聚反应.本研究采用非水解溶胶-凝胶技术[6],在1200℃制备出长径比达到 60～70的高质量莫来石晶须.1 实验1.1 试样制备以无水三氯化铝(CP)、正硅酸乙酯(AR)为前驱体,乙醚(AR)为氧供体,二氯甲烷(AR)为溶剂,氟化铝(Tech)为晶须催化剂.化学试剂均由国药集团化学试剂有限公司生产. 根据莫来石的理论组成n(Al)∶n(O)∶n(Si)= 6∶13∶2,在通风橱中称取0.0537mol无水三氯化铝置于 100mL的干燥锥形瓶中,量取 0.0179mol正硅酸乙酯倒入其中,室温快速磁力搅拌 15min,得到土黄色前驱体混合物;添加 0.0448mol 乙醚,继续搅拌得到黑色前驱体混合物溶液;然后采取恒压和恒容两种工艺制备莫来石干凝胶粉.恒压工艺是将前驱体混合物溶液于110℃油浴中加热回流 24h,得到莫来石干凝胶;恒容工艺则是在前驱体混合溶液中加入一定量的二氯甲烷作溶剂,继续搅拌 15min后,置于120mL的反应容弹内,在 90～130℃烘箱中,利用前驱体溶液自身产生的压力反应 16～32h,将生成的固态凝胶在烘箱低温干燥,得到干凝胶,分别将这两种干凝胶研磨粉碎备用.按内加和外置两种方式引入0～6wt%的氟化铝.其中,内加方式是将氟化铝与干凝胶粉直接混合均匀,造粒后用粉末压片机在 0～24MPa 的压力下压制成试片,然后将其置于密闭坩埚中煅烧;外置法是将干凝胶粉造粒后压成试片,再将试片置于已装有所需氟化铝的密闭坩埚中煅烧.煅烧制度如下:以4℃/min加热到350℃;然后,再以10℃/min升至 1100～1260℃,保温 1h,即可制备出高质量的莫来石晶须.1.2 测试及表征使用德国D8AdvanceX-ray衍射仪分析干凝胶在热处理过程中的晶相组成(CuKα辐射,波长0.154nm);运用中科院科学仪器厂 KYKY-1000B扫描电子显微镜观察莫来石晶须的形貌;借助日本JS M-2010透射电镜观察样品的形貌,并通过选区电子衍射和高分辨象分析晶须的取向生长.2 实验结果与讨论2.1 干凝胶粉制备工艺对合成莫来石晶须的影响分别以恒压和恒容两种工艺制备的莫来石干凝胶粉为原料合成莫来石晶须,结果见图 1(a)、(b).其中,外置氟化铝的用量为 3wt%,成型压力为12MPa,煅烧温度为1200℃.从图 1可以看出采用恒压工艺制备出的莫来石干凝胶粉所得到的晶须长径比大、质量好;而由恒容工艺制备出的莫来石晶须尺寸短、长径比小.恒容工艺制备出的莫来石干凝胶粉,比表面积很大(259.4m2/g),在煅烧过程中容易烧结成块,使晶须的生长空间受限制,致使晶须短小.相比之下,恒压工艺制备的干凝胶粉活性适中(比表面积为 16.4m2/g),在煅烧时,粉料不易烧结成块,有利于 F2气氛的扩散,给晶须生长提供了较大的空间,从而得到了大长径比的晶须.在以下的讨论中,均以恒压工艺制得的莫来石凝胶粉为原料.2.2 氟化铝引入方式对合成莫来石晶须的影响图 1 采用恒压(a)和恒容(b)两种工艺制备的干凝胶粉合成的莫来石晶须Fig.1 SEM micrographs ofmullite whiskers synthesized from xerogels prepared at constant pressure(a)and constant volume(b)为了探讨氟化铝引入方式对合成莫来石晶须的影响,采取了内加和外置两种加料方式,其中氟化铝的用量为 3wt%,成型压力为 12MPa,煅烧温度为1200℃.从图 2(a)可以看出:采用内加方式,试样仅出现少量长径比小的棒状晶须,大多为颗粒状和絮状夹杂物;而采取外置方式 (见图 2(b)),可得到晶须产率高、长径比大且分布均匀的莫来石晶须,且其中夹杂物少.这主要是由于采取内加方式时,矿化剂在试样中产生液相,促进了试样的致密化,导致气相氟化物不易在致密粉体中渗透,从而影响气相反应,不利于晶须生长.相比之下,外置方式不会在试样中产生液相而导致试样致密化,气相氟化物与固体粉料之间的气-固反应不受影响,其产物组成及反应过程也较容易控制,且反应均匀.因此,氟化铝以外置方式引入效果好.2.3 氟化铝用量对制备莫来石晶须的影响图3给出了氟化铝用量为 0、3wt%和 6wt%时试样的 XRD图谱,其中氟化铝的加料方式为外置,成型压力为12MPa,煅烧温度为1200℃.从图3中可以看出,当不加氟化铝时,试样所产生的衍射峰均为莫来石的衍射峰,无任何杂峰;当添加量为3wt%时,试样中的主晶相为莫来石,并伴随少量的刚玉相;随着氟化铝含量增至 6wt%,试样中除了主晶相莫来石以外,还含有刚玉相.图 2 采取内加(a)和外置(b)两种方式引入AlF3所制得的晶须Fig.2 SEM micrographs of mullite whisker with the inner addition(a)and outside addition(b)ofAlF3图 3 不同氟化铝用量制备的莫来石晶须的 XRD图谱Fig.3 XRD patterns of mullite whisker prepared with various amountsofAlF3(a)withoutAlF3;(b)3wt%AlF3;(c)6wt%AlF3不同氟化铝用量制备的莫来石晶须的 SEM照片见图 4.从图 4(a)中可以看出:不加氟化铝的试样,主要是颗粒状和板状结构相混合的莫来石;当加入3wt%氟化铝时(见图 4(b)),颗粒状莫来石已消失,取而代之的是沿一维方向生长的莫来石晶须,其直径为 0.2～2.0μm、长径比高达 60～70;当氟化铝的量为 6wt%时,莫来石呈现沿二维方向生长、厚度为0.5～1.5μm的片状结构 (见图 4(c)).当氟化铝不加或用量极少时,试样中产生的气相浓度低,晶须生长及晶须合成量受到限制;当氟化铝过多时,所产生的气相反应物浓度过大,超过了晶须定向生长所需的量,从而引起晶须径向生长的二维成核[7],莫来石易形成片状结构.AlF3与试样的适当配比是制备莫来石晶须的关键之一,其最佳用量为 3wt%.为了确定合成莫来石晶须的生长方向,图 5给出晶须的 TEM照片、选区电子衍射花样图(SAED)和HR-TEM照片.从图 5(a)和(b)中可看出,此棒状莫来石为单晶结构.根据衍射花样标定的 d值,计算出莫来石的晶胞常数为a=0.757nm,b=0.769nm,c= 0.288nm,与莫来石 XRD标准衍射卡片 (PDF15-0776)一致.同时还可知莫来石晶须的晶带轴为[1-10],沿晶须轴向衍射斑点对应于[001],莫来石的生长方向平行于[001],即沿 c轴方向生长 (见图5(c)).这主要是由于莫来石晶体中的{110}面具有相对其它晶面更低的表面能[8].因此,当莫来石针状晶核形成以后,其沿着 c轴的方向(也即[001]方向)以{110}面为界形成晶须.2.4 成型压力对制备莫来石晶须的影响不同成型压力对制备莫来石晶须的影响见图 6,其中氟化铝的加料方式为外置,氟化铝的用量为3wt%,煅烧温度为1200℃.从图 6(b)中可以看出当成型压力为 12MPa 时,此时获得的莫来石晶须质量最高、长径比最佳;当成型压力为 0时 (见图 6(a)),没有晶须存在,都是等轴状的晶粒,且晶粒与晶粒之间较为疏松;而当压力增至 24MPa 时 (见图 6(c)),莫来石晶粒并未生成一维莫来石晶须,而呈现米粒状颗粒,颗粒与颗粒间产生明显的烧结现象.当其他条件不变时,适当的压力使坯体密度适中,这一方面有利于矿化剂气相的扩散反应,晶须生长空间大,晶核易定向生长;另一方面也有利于莫来石颗粒间的固相传质.因此,最终形成的晶须量多、长径比大且分布均匀;反之,成型压力过大则坯体颗粒之间过于致密,导致气相传质困难,晶须生长空间受限,容易导致莫来石颗粒间的固相烧结.当成型压力为 0时,尽管此时气相传质很快,但是莫来石晶粒间传质很困难,无法确保晶粒沿一维优先生长,只能得到等轴状莫来石晶粒.图 4 不同氟化铝用量制备的莫来石晶须的 SEM照片Fig.4 SEM micrographs ofmullite whisker prepared with various amounts ofAlF3(a)WithoutAlF3;(b)3wt%AlF3;(c)6wt%AlF3图 5 晶须试样的 TEM照片(a),SAED(b)和 HRTEM照片(c)Fig.5 TE Mimage(a),SAED pattern(b)and HRTEM micrograph(c)of the whisker图 6 不同成型压力下制备的莫来石晶须的 SEM照片Fig.6 SEM micrographs ofmullite whisker prepared under various forming pressures(a)W ithout pressure;(b)12MPa;(c)24MPa图 7 不同煅烧温度下制备的莫来石晶须的 SEM照片Fig.7 SEM micrographsofmullite whisker calcined at differenttemperatures(a)1100℃;(b)1200℃;(c)1260℃2.5 煅烧温度对制备莫来石晶须的影响不同煅烧温度对制备莫来石晶须的影响见图 7,其中氟化铝的加料方式为外置,氟化铝的用量为3wt%,成型压力为12MPa.从图7中可以看出:晶须的最佳煅烧温度为1200℃;温度为1100℃时,所制备的晶须长径比较短;温度为1260℃时,晶须已明显粗化,长径比减小.煅烧温度较低时的氟化物气相浓度很低,气相传质不足,莫来石颗粒一维发育不够,故制备出的莫来石晶须长径比较小;煅烧温度过高,晶体沿各个方向生长速度差别缩小,导致晶须粗化.3 结论1)以正硅酸乙酯、无水氯化铝为前驱体,乙醚为氧供体,二氯甲烷为溶剂,通过非水解溶胶-凝胶法,引入氟化铝为矿化剂,制备出直径为 0.2～2.0μm、长径比高达 60～70的莫来石晶须;2)制备莫来石晶须的优化工艺为:采用恒压回流工艺制备的莫来石干凝胶粉,在12MPa的压力下压制成型,通过外置方式引入 3wt%的氟化铝,最后在1200℃热处理,保温 1h.参考文献:【相关文献】[1]王洪彬,张玉军,张敏.莫来石晶须研究进展.山东轻工业学院学报,2005,19(4):94-97.[2]Park YM,Yoon S Y,Stevens R,et al.Mullite whiskers derived from coal fly ash.Mater.Sci.Eng.A,2007,454-455:518-522.[3]Hashimoto Shinobu,YamaguchiAkira.Synthesis of needlelike mullite particles using potassium sulfate flux.J.Eur.Ceram.Soc., 2000,20(4):397-402.[4]Okada K,Otsuka N.Synthesis of mullite whiskers by vapour-phasereaction.J.Mater.Sci.Lett.,1989,8(9):1052-1054.[5]IsmailM,Arai H,Nakai Z,et al.Mullite whiskers from precursor gelpowders.J.Am.Ceram.Soc.,1990,73(9):2736-2739.[6]Niederberger M,Garnweitner anic reaction pathways in the nonaqueous synthesis ofmetal oxide nanoparticles.Chem.Eur.J., 2006,12(28):7282-7302.[7]李武.无机晶须.北京:化学工业出版社,2005:4-5.[8]Hong S H,Messing G L.Anisotropic grain growth in diphasic gel derived titania-doped mullite.J.Am.Ceram.Soc.,1998,81(5): 1269-1277.。

william henry perkin雅思阅读原文摘要：I.引言- 介绍William Henry Perkin- 提到他的重要发现II.合成染料的诞生- 描述Perkin如何发现合成染料- 解释mauveine的制备过程和性质III.合成染料对纺织业的影响- 分析Perkin的发现如何改变纺织业- 描述合成染料的优点IV.结论- 总结Perkin的贡献- 强调他的发现对现代社会的重要性正文：I.引言William Henry Perkin, an English chemist, made a groundbreaking discovery in 1856 that would revolutionize the textile industry.His invention, the first synthetic dye, was named mauveine and would forever change the way we dye clothing.II.合成染料的诞生Perkin"s discovery of synthetic dye was a happy accident.While attempting to create a cure for malaria, he synthesized aniline, a compound found in coal tar.Perkin then mixed aniline with other chemicals and, to his surprise, produced a purple dye.This dye, which he named mauveine, was later used to dye clothing.Mauveine was the first synthetic dye ever created, and its properties were remarkable.It was colorfast, meaning it did not fade easily, and it could be used to dye a wide range of materials, from silk to cotton.III.合成染料对纺织业的影响Perkin"s discovery had a profound impact on the textile industry.Before mauveine, dyes were derived from natural sources such as plants and animals, which were limited in quantity and often expensive.With the advent of synthetic dyes, manufacturers could now produce colors inexpensively and in vast quantities.This development led to a rapid expansion of the textile industry, as companies could now offer a wider range of colors and patterns to consumers.Synthetic dyes also had other advantages, such as being more resistant to fading and washing.IV.结论William Henry Perkin"s discovery of the first synthetic dye, mauveine, was a significant milestone in the history of chemistry and the textile industry.His invention not only transformed the way textileswere produced but also laid the foundation for the development of many other synthetic dyes.Today, synthetic dyes are an integral part of our daily lives, and Perkin"s contribution is remembered for its profound impact on modern society.。

高二测试题制作希腊风味烤羊排配薄荷酱英语作文In the realm of culinary delights, the combination of succulent lamb chops and refreshing mint sauce reigns supreme, offering a harmonious blend of flavors that captivate the senses and transport one to the sunkissed lands of Greece. Today, we embark on a gastronomic journey to create a dish that embodies the essence of Greek cuisine – Grilled Lamb Chops with Mint Sauce.To begin our culinary adventure, we must carefully select the finest cuts of lamb chops, ensuring they are of the highest quality and tenderness. The key to a delectable dish lies in the preparation, and marinating the lamb chops in a blend of olive oil, garlic, lemon juice, and a medley of Mediterranean herbs is essential to infuse them with rich flavors.As the lamb chops luxuriate in their marinade, we turn our attention to crafting the pièce de résistance – the mint sauce. Fresh mint leaves, garlic, Greek yogurt, a touch of lemon zest, and a hint of honey are meticulously combined to create avelvety sauce that complements the robust flavors of the grilled lamb chops.As the grill crackles to life, the tantalizing aroma of sizzling lamb fills the air, heralding the imminent culinary delight that awaits. Each lamb chop is carefully placed on thegrill, where it is seared to perfection, resulting in a tantalizing smoky char that enhances its natural juiciness.Upon achieving the desired level of doneness, the lamb chops are artfully arranged on a platter, a savory tableau of goldenbrown perfection. The mint sauce, with its verdant hue and refreshing aroma, is drizzled over the lamb chops, creating a symphony of flavors that dance upon the palate.With eager anticipation, we take our first bite, savoring the tender lamb, imbued with the smoky essence of the grill and the herbaceous notes of the mint sauce. The marriage of flavors is exquisite, a testament to the culinary mastery that has goneinto creating this Greekinspired masterpiece.In conclusion, the creation of Grilled Lamb Chops with Mint Sauce is a culinary odyssey that celebrates the vibrant flavors of Greek cuisine. From the tender lamb chops to the refreshing mint sauce, every element of this dish harmonizes to create a symphony of taste that transports the diner to the sundrenched shores of Greece. Embrace the flavors, savor the experience, and let each bite carry you away on a gustatory voyage like no other.。

高三测试题制作希腊烤羊排配孜然英语作文Greekstyle Roast Lamb with CuminIntroduction:When it comes to combining different culinary traditions, Greekstyle roast lamb with cumin is an exceptional dish that perfectly blends Mediterranean and Middle Eastern flavors. This mouthwatering recipe not only showcases the rich history of Greek cooking but also adds a unique twist with the aromatic touch of cumin. In this essay, we will delve into the preparation and cooking process of this delectable dish, highlighting its cultural significance and tantalizing taste that makes it a standout choice for any occasion.Ingredients:1 leg of lamb (approximately2 kg)4 cloves of garlic, minced2 tablespoons of olive oil1 tablespoon of dried oregano1 tablespoon of dried thyme1 tablespoon of ground cuminSalt and pepper to tasteLemon wedges for garnishMarinade Preparation:To prepare the marinade, combine the minced garlic, olive oil, dried oregano, dried thyme, ground cumin, salt, and pepper in a mixing bowl. Mix the ingredients thoroughly until they form a pastelike consistency.Marinating the Lamb:Place the leg of lamb in a large dish and generously coat it with the marinade, ensuring that the meat is evenly covered. Cover the dish with plastic wrap and let it marinate in the refrigerator for at least 4 hours, or preferably overnight. This allows the flavors to penetrate the meat and infuse it with arich and savory taste.Cooking Instructions:1. Preheat the oven to 180°C (350°F).2. Remove the marinated lamb from the refrigerator and let it come to room temperature.3. Place the lamb in a roasting pan and cover it with aluminum foil.4. Roast the lamb in the preheated oven for approximately22.5 hours, depending on the desired level of doneness. For mediumrare, aim for an internal temperature of 6063°C (140145°F).5. Once the lamb is cooked to perfection, remove it from the oven and let it rest for 1520 minutes before carving.6. Garnish the roasted lamb with lemon wedges for arefreshing citrusy touch.Conclusion:In conclusion, the Greekstyle roast lamb with cumin is a culinary delight that embodies the essence of both Greek and Middle Eastern cuisines. The tender and succulent meat, infused with aromatic herbs and spices, creates a harmonious blend of flavors that is sure to impress even the most discerning palates. Whether served at a festive gathering or a cozy family dinner, this dish is a true celebration of cultural diversity and gastronomic excellence. Try your hand at making this exquisite recipe and experience the magic of Greekinspired cuisine with a tantalizing twist of cumin. Bon appétit!。

Available online at ScienceDirectJournal of the European Ceramic Society35(2015)711–721Waste-to-resource preparation of a porous ceramic membrane support featuring elongated mullite whiskers with enhanced porosity and permeance Li Zhu a,b,Yingchao Dong a,b,∗,Stuart Hampshire c,Sophie Cerneaux d,Louis Winnubst ea CAS Key Laboratory of Urban Pollutant Conversion,Institute of Urban Environment,Chinese Academy of Sciences,PR Chinab Ningbo Urban Environment Observation and Research Station—NUEORS,Chinese Academy of Sciences,PR Chinac Materials and Surface Science Institute(MSSI),University of Limerick(UL),Limerick,Irelandd Institut Europeen des Membranes,UMR5635,Place Eugene Bataillon,34095Montpellier Cedex5,Francee Inorganic Membranes,MESA+Institute for Nanotechnology,University of Twente,PO Box217,7500AE Enschede,The NetherlandsReceived16June2014;received in revised form1September2014;accepted9September2014Available online1October2014AbstractDifferent from traditional particle packing structure,a porous structure of ceramic membrane support was fabricated,featuring elongated mullite whiskers with enhanced porosity,permeance and sufficient mechanical strength.The effect of additives(MoO3and AlF3)and sintering procedure on open porosity,mechanical properties,pore size distribution,micro-structure,phase structure,and permeance of the membrane supports was characterized in detail.The introduction of MoO3and AlF3promoted formation of a porous whisker-interlocked structure,which effectively improved open porosity and permeance.A mullite membrane support containing5wt.%MoO3and4wt.%AlF3exhibited an open porosity as high as48.6±0.5%,a mechanical strength of81.2±3.2MPa at1200◦C,and the value of permeance was higher than the membrane without any additives.Such enhancements in porosity and permeance,with sufficient mechanical strength,were a result of tortuosity decrease due to a porous structure of interlocked mullite whiskers.©2014Elsevier Ltd.All rights reserved.Keywords:Ceramic membrane support;Porosity;Mechanical strength;Mullite whiskers;Permeance1.IntroductionPorous ceramic separation membranes are used in industrial fields due to their unique advantages,such as excellent tempera-ture stability,good pressure resistance,good chemical stability, long life and good antifouling properties.1However,commercial porous ceramic membranes still cannot fulfill increasing envi-ronmental requirements at a large scale such as separation in strong alkaline media and massive liquid waste treatment due to the limited types of membrane materials2(such as Al2O3,ZrO2, SiO2,TiO2and their composites).Besides,high cost,associated with starting materials and formation/sintering processes,makes extensive applications of ceramic membranes still limited.3,4As ∗Corresponding author at:CAS Key Laboratory of Urban Pollutant Conver-sion,Institute of Urban Environment,Chinese Academy of Sciences,Xiamen, PR China.Tel.:+8605926190790;fax:+8605926190790.E-mail addresses:ycdong@,dongyc9@(Y.Dong).a result,the preparation and potential applications of porous mineral-based ceramic membranes(kaolin,5bauxite,6sepiolite clay,7industrial solid waste coalfly ash,8etc)have attracted more attention due to the low cost of abundant raw materi-als available worldwide.For example coalfly ash emerges as a by-product from the combustion of raw coal in thermal power plants.9Without suitable treatment,fly ash may be a source of dust which adversely affects our environment.Therefore,it is necessary to utilize this waste not only to decrease environmen-tal pollution but to produce high added-value products from it. Especiallyfly ash containing Al2O3and SiO2is suitable for the fabrication of dense mullite-based ceramics,as has been proven in.10,11Recently a study has been made on the conversion of coal fly ash to mullite(3Al2O3·2SiO2)for the preparation porous ceramic membranes.12As a structural material,porous mineral-based mullite is expected to be a promising candidate for ceramic membrane supports especially because of its excellent high temperature resistance,good corrosion resistance,abundant natural Al and/10.1016/j.jeurceramsoc.2014.09.016 0955-2219/©2014Elsevier Ltd.All rights reserved.712L.Zhu et al./Journal of the European Ceramic Society35(2015)711–721Si-sources,low cost,and environment friendliness.13These properties are especially important for porous mullite,which is used asfilter membrane for treatment of great volumes of liquid/gas effluents,which requires the use of porous support with higher porosity and good mechanical strength in order to maintain a lower pressure drop across thefilter membrane and to withstand the pressure gradient imposed during practical separation applications.Traditionally,the open porosity of a ceramic membrane is limited by the intergranular packing effect of the starting pow-der or precursor,mainly depending on its morphology and particle size distribution.It is well known that porosity can be effectively controlled by varying sintering conditions such as sintering temperature and dwelling time.14High tempera-ture partial sintering is required to produce sintering necks, endowing porous ceramic membrane with sufficient strength, while degrading open porosity to some extent.Normally,an improvement in open porosity,which is required to endow a lowfluid resistance,is achieved with addition of pore-forming agents such as graphite powder or some organic compounds,15,16which burn out or decompose completely dur-ing heating.However,the pores produced in this way are usually believed to deteriorate the mechanical reliability.17It is usually hard and thus of great importance tofind a way to produce high porosity without alteration of mechanical strength of ceramic membrane supports,which are expected to withstand large pressure gradient imposed during prac-tical separation applications.Apart from high mechanical strength,a proper ceramic membrane support should have high permeability.18Recently,mullite whiskers have been widely investigated as candidates for reinforcement of ceramic-based composites due to their high aspect ratio and high strength.19Several approaches, such as addition of AlF311,19,20to starting material mixtures,are developed to produce mullite-whisker-reinforced composites.In order to further enhance mullite phase content at low tempera-tures,some sintering aids(such as V2O5,21MgO,22TiO212and WO323)are used during fabrication of low-cost porous mullite. However,there are few reports with MoO3as sintering addi-tive.Since Mo and W are in the same subgroup of the element periodic table,associated with the lower melting point of MoO3 (795◦C),it is expected that addition of MoO3accelerates the growth of mullite crystals and thus enhances mullite content at lower temperatures.Different from traditional particle packing structure processed by partial sintering,in this work,with MoO3and AlF3as additives,a highly porous structure of inter-locked mul-lite whiskers is realized in mullite membrane support made from waste coalfly ash and bauxite.The present study aims at elaborating a new type of porous structure for ceramic membrane support with enhanced porosity and permeance,but without significant degradation of mechanical property.The effect of additives and sintering parameters on the main prop-erties of porous mullite membrane supports is studied in detail, mainly including porosity,mechanical properties,pore size dis-tribution,micro-structure(SEM and phase compositions)and permeance.2.Experimental procedures2.1.Starting materials for membrane supportCoalfly ash(Ningbo,Zhejiang Province,China)and nature bauxite(Yangquan,Shanxi Province,China)were used as the starting materials.AlF3(98–102%,Guangfu Fine Chemical Reagent Ltd.,Tianjin,China)and MoO3(Sinopharm Chemi-cal Reagent Co.,Ltd)were used as crystallization catalyst and mineralizer,respectively.Based on mullite stoichiometric composition (3Al2O3·2SiO2),a series of MoO3–AlF3doped and undoped mullite membrane supports were prepared by adding various weight percents(wt.%)of AlF3(x wt.%)and MoO3(y wt.%) into the powder mixture offly ash and bauxite.All samples are labeled as A x M y.A stands for AlF3,M for MoO3,and the numbers following them represent their mass percentage in the samples(e.g.A0M0for the sample without addition of AlF3 and MoO3,A4M5for the sample with addition of4wt.%of AlF3and5wt.%of MoO3).2.2.Fabrication of membrane supportThe raw materials with different compositions were wet-ball-milled in distilled water for12h using a planetary ball-milling machine(SFM-1,Hefei Kejing Materials Technology Co.,Ltd) at a milling speed of400rpm.After complete drying,the milled powders were uniformly mixed with organic binder PV A-1750 (5.0wt.%solution)in an alumina mortar and then uniaxially pressed into cylindrical pellets(20mm in diameter and1–2mm in thickness)at a pressure of190MPa.The green disc-shape membrane supports were placed in a closed alumina crucible and sintered in an electrically heated muffle furnace in air atfinal temperatures ranging from1100◦C to1500◦C for 2h.2.3.Characterization and testParticular emphasis is placed on characterization of mem-brane properties of the supports:open porosity,pore size distribution,mechanical strength,gas and water permeances.A detailed microstructural analysis was performed to under-stand the formation process and the reinforcement of this mullite membrane support.The particle size distribution offly ash and bauxite was determined by a laser particle size analyzer(Mastersizer2000, Malvern Instruments Ltd.,UK).Chemical compositions of the raw materials(coalfly ash and natural bauxite)were exam-ined by X-rayfluorescence spectrometry(WDXRF,PANalytical Corporation,The Netherlands).Open porosity was determined by the Archimedes method24 with water as the liquid medium.Pore size distribution was measured by a pore size distribution analyzer(PSDA-20,Nan-jing Gaoqian function materials Co.Ltd.,China)based on a gas–liquid displacement method.The pore diameter can beL.Zhu et al./Journal of the European Ceramic Society35(2015)711–721713 calculated from the Washburn’s equation using the bubble-pointmethod22,25,26:d=4γcosθp(1)whereγis the surface tension coefficient of the liquid,θis the contact angle of the liquid on the pore wall and p is the applied pressure difference.In most cases,the shape of the pore tunnels is irregular,and the pore size is thus defined as the diameter of a circle which area is equal to the pore throat.25Biaxialflexural strength(BFS)was measured by a universal testing machine(AGS-X,Shimadzu Ltd.,Japan).BFS was cal-culated using the formula for maximum tensile stress given by Timoshenko and Woinowsky-Krieger27:BFS(MPa)=Nt2{(1+ν)[(0.485ln(a/t)+0.52]+0.48}(2)where N is the load(N),νis Poisson’s ratio(ν=0.26in this study),a is the radius of the support circle(m)and t is the thickness of the specimen(m).Weibull analysis was conducted on the results of biaxialflex-ural strength.The Weibull analysis curves28were made using lnσand lnln[1/(1−P f)]plot as X-axis and Y-axis,respectively, whereσis the biaxialflexural strength,P f is he fracture proba-bility.The latter P f is defined by the relation P f=i/(N+1),where i is the rank in biaxialflexural strength from smallest to largest and N denotes the total number of samples(here N=10in our study).The fracture energy was determined using the following equation:E a=Ni=1E iπa2t i×10−3N(3)where E a is the fracture energy per unit volume,E i is the fracture energy of sample i,a is the circumcircle radius of the three support balls(a=5mm in our study),N is the total number of test bodies(N=10in our study),t i is the average thickness of sample i.Microstructures of the sintered samples were analyzed by scanning electron microscopy(SEM,S-4800,Hitachi LTD., Japan).Phase analysis of the raw materials and sintered samples was determined by X-ray diffraction(XRD,D8advance,Bruker Corporation,Germany).XRD quantitative analysis based on the normalized reference intensity ratio(RIR)method,was adopted to calculate the mullite content in the sintered samples.292.4.Waterflux and permeance studyA home-made dead-endflow setup was used for water per-meance studies.The stainless-steel setup mainly consists of a top cylindrical water container and a base plate with a provi-sion to keep a support.The support is rested on a perforated disk(casing)and placed in the bottom compartment.The trans-membrane pressure for these experiments was in the range of 0.05–0.3MPa.The permeateflow rate was recorded at10min Fig.1.Open porosities of the sintered membrane supports with addition of 0–10%wt.%of MoO3and0–4%wt.%of AlF3as a function of sintering tem-perature.intervals for1h and the measurements were repeated for all the samples.2.5.N2flux and permeance studyN2permeance studies were performed at25◦C at differential pressures ranging from0.05to0.3MPa with0.05MPa intervals in a dead-end mode with the inlet pressure controlled by a pres-sure regulator and a digital pressure gauge.The gasflow across the membrane was measured with a bubbleflow meter on the exit gas stream of the membrane support.The samples were held at each pressure step until a steadyflow rate was achieved. 3.Results and discussion3.1.Characterization of membrane materialsThe chemical compositions of the coalfly ash and bauxite are given in Table1.The coalfly ash mainly consists of mullite (3Al2O3·2SiO2,PDF no.15-0776),belonging to primary mul-lite,which is formed from aluminosilicate clay minerals duringthe combustion process of raw coal.As to bauxite,the main crystalline phases detected are diaspore(AlO(OH),PDF no.87-0705)and kaolinite(Al2O3·2SiO2·2H2O,PDF no.78-2109). The average particle diameters of coalflyash and bauxite parti-cles are2.1␮m and1.2␮m,respectively.Most of the mixtures particle size after ball-milling center between1.1␮m(d10)and 4.3␮m(d90)in diameter.3.2.Open porosity and mechanical propertyFig.1indicates that the open porosity without additives (A0M0)shows a gradually-decreasing trend with sintering temperature.This result is similar to porous mullite,derived from the kaoline–alumina system,30but different from the trend of increasing porosity with increasing sintering temper-ature at certain range for thefly-ash–bauxite system involving714L.Zhu et al./Journal of the European Ceramic Society35(2015)711–721Table1Main chemical composition(wt.%)offly ash and natural bauxite measured by semi-quantitative XRF.Materials Chemical composition(%)Al2O3SiO2CaO Fe2O3TiO2SO3K2O Na2O Others Fly ash44.7644.17 4.57 3.02 1.920.440.40.220.49 Bauxite63.5310.410.477.08 2.980.180.280.150.52 The loss on ignition offly ash and bauxite is1.01and14.40wt.%,respectively.a sintering self-expansion,as reported in Ref.[6],which is possibly due to the difference in chemical compositions of raw materials.The samples with MoO3and AlF3(A4M5 and A4M10)have higher porosities at all temperatures as compared with A0M0.For A4M5,porosities as high as 46.9±0.4–48.6±0.5%are achieved at1100–1300◦C,then decreased to41.6±0.9–29.8±1.2%at1400–1500◦C due to the occurrence of a sintering densification.With addition of the same amount of AlF3(4wt.%),open porosity slightly increases with MoO3content(from5to10wt.%).These results indi-cate that co-addition of MoO3and AlF3is quite effective in enhancing open porosity of mullite membrane supports.When comparing A4M5with A0M0,it is interesting to note that the increase in porosity of the samples with addition of AlF3and MoO3is not followed by the degradation in mechanical strength at temperatures below1300◦C(see Fig.2a).The biaxial flexural strengths of the A4M5samples are at the same level with those of the samples without any additive from1100◦C to 1200◦C.Although the strengths of A4M5are lower than those of A0M0at1300–1500◦C,higher porosity enhancements are realized for A4M5when compared with A0M0.In particular, given the same level of biaxialflexural strength,A4M5always exhibits higher porosity than A0M0(Fig.2b).Fracture energy(Fig.2c)of A4M5and A0M0gradually increases with sintering temperature,which is consistent with the variation of biaxialflexural strength with sintering tem-perature(Fig.2a).At each temperature,A4M5exhibits higher fracture energy than A0M0.From1100to1400◦C,the fracture energy of A0M0increases from8.7±2.1to25.4±2.0kJ m−3. Upon MoO3and AlF3addition,the samples exhibit higher fracture energy(9.6±2.1to30.0±2.2kJ m−3).These improve-ments of fracture energy are ascribed to a new structure of a large quantity of compact interlocked needle-like mullite whiskers, which will be studied by SEM(Fig.7).This effect is similar to that reported by Li et al.,21where microstructural homogene-ity was improved and mechanical properties could be tuned by doping with V2O5.Fig.2d shows the Weibull analysis of the biaxialflexural strength results of A0M0and A4M5sintered at1200–1400◦C. Most of the points(lnσversus lnln[1/(1−P f)])center close to the correspondingfit lines,which proves a good reliability of the BFS results.In summary,with addition of MoO3and AlF3,open poros-ity is significantly improved without degradation of mechanical strength.At the same level of strength,A4M5always exhibits higher open porosity than A0M0.The A4M5membrane sup-port sintered at1200◦C possesses an enhanced open porosity as high as approximately48.6±0.5%,and an excellent strength of 81.2±3.2MPa.Forfiltration membrane application,pore size distribution,gas and water permeation properties are important and thus studied in the following subsections.3.3.Pore size distributionPore size distributions are closely related tofinal sintering temperatures.A0M0shows a unimodel distribution of pore size for all the sintering temperatures.The average pore sizes of A0M0(Fig.3a)are found to be0.32,0.33and0.37sintered at 1200◦C,1250◦C,and1300◦C,respectively.A gradual increase in average pore size is observed due to the sintering-induced growth of grains(which will be justified by the SEM results, Fig.6),leading to the formation of large pores and elimination of small pores at high temperature.These trends are similar with mullite membrane supports prepared in previous work.6 Compared with A0M0,the mean pore sizes of A4M5become smaller at all sintering temperatures.The average pore diameters at1200◦C,1250◦C and1300◦C are0.18,0.15and0.26,respec-tively(Fig.3b).The membranes supports show typical bimodal pore size distributions having maximum number of pores in two regions,56–70%of pores between0.20and0.45␮m and 30–44%of pores between0.08and0.20␮m.Based on the SEM images shown in Fig.7,the bimodal pore size distributions are probably due to the formation and growth of stiff skeleton needle-like mullite crystals,resulting in formation of somefiner pores among them.263.4.XRD analysisFig.4indicates that the two XRD patterns of A0M0and A4M5sintered at1100◦C are similar,consisting of mullite(PDF no.15-0776)characteristic peaks,weak characteristic peaks of cristobalite(PDF no.27-0605)and corundum(PDF no.10-0173).The dependence of mullite phase content on sintering temperature based on RIR analysis(Fig.5)shows the mullite content in A0M0(28%)is lower than that in A4M5(48%).In the A0M0sample,cristobalite is detected until1250◦C,which reacted with alumina,contributing to the formation of mullite phase.While in the A4M5sample,cristobalite is not detected when the sintering temperature increases up to1200◦C,where the mullite content is72%.This great increase in mullite content from48%to72%is due to the rapid formation of secondary mul-lite from1100◦C to1200◦C.The content of mullite does not significantly increase between1200◦C and1400◦C.By con-trast,the content of mullite in A0M0increases gradually from 32%to76%as the sintering temperature increases from1100◦C to1300◦C.L.Zhu et al./Journal of the European Ceramic Society35(2015)711–721715Fig.2.Biaxialflexural strength test results of the membrane supports with various compositions(a)biaxialflexural strength and open porosity versus sintering temperature,(b)biaxialflexural strength versus porosity,(c)fracture energy versus sintering temperature and(d)Weibull analysis.Standard deviations are not presented as they are very small.Fig.3.Pore size distributions of A0M0((a)and(A))and A4M5((b)and(B))sintered at different temperatures.716L.Zhu et al./Journal of the European Ceramic Society 35(2015)711–721Fig.4.XRD patterns of the A0M0(a)and A4M5(b)membrane supports sintered at various temperatures for 2h.Fig.5.Effect of sintering temperature on mullite content in the A4M5and A0M0membrane supports.During high-temperature sintering,Firstly,AlF 3reacted with O 2to form AlOF,and then AlOF reacted with the reaction prod-uct SiF 4to produce mullite at a lower temperature.The existence of MoO 3lowered the melting temperature of silica-rich glassy liquid and decreased the high-temperature viscosity of the liq-uid system,which was favorable to the formation of silica-rich liquid phase and thus promoted mass transportation during the reaction between Al 2O 3and SiO 2.The Al 2O 3dissolved into the glassy phase for second mullite formation.While the reaction between Al 2O 3and SiO 2went on,the mullite crystals grew up.The excess SiO 2in fly ash was thus consumed with the rapid for-mation of large crystals of secondary mullite at 1100–1300◦C.It is reasonable to assume that MoO 3acted as heterogeneous centers where mullite nucleation could be induced at lower tem-peratures,leading to lower mullitization temperature.This is similar with the positive effect of V 2O 5on sintering of mul-lite membrane supports.21With AlF 3and MoO 3addition,the temperature,at which mullite phase was formed,is lowered by 150◦C as compared with the samples prepared without any additives.3.5.Microstructural analysis of membrane supportThere is a great difference in microstructure evolution for A0M0and A4M5(Figs.6and 7).From Fig.6a,it is found that porous structure is formed by partial-sintering of mixture particles of fly ash and bauxite without morphological change (A0M0)at 1100◦C.From 1200to 1300◦C (Fig.6b and c),sin-tering is gradually enhanced with the presence of larger pores at 1300◦C,which is consistent with the pore size distribution results (see Fig.3a).With further increasing firing temperature up to 1400◦C,an obvious densification is observed,which cor-responds to the rapid decrease in open porosity as discussed above (see Fig.1).Comparing Fig.6a–d with Fig.7a–d,it is found that with the addition of the additives,a large amount of very fine mul-lite whiskers are observed to be distributed around some large particles in a porous structure at 1100◦C.With increasing tem-perature to 1200◦C,a uniform porous microstructure is formed,entirely composed of grown mullite whiskers (Fig.7b),which act as a skeleton of pore structure.With further increasing sin-tering temperature (1300◦C)(Fig.7c),mullite whiskers grow thicker and longer and interlocked with each other.A highly porous structure is observed for the sample sintered at 1300◦C.The formation of stiff skeleton needle-like mullite is very favor-able to increase the open porosity (consistent with the above results in Fig.2).The surface of A4M5-1300is more porous than that of A0M0-1300,indicating that the accelerated anisotropical growth of mullite whiskers induced by AlF 3and MoO 3favors the enhancement of open porosity (consistent with the above results in Fig.1).This type of grain morphology is quite essen-tial for developing highly porous filtration membrane with strong mechanical integrity.Fig.8shows the freshly fractured surface SEM images,after biaxial flexural strength tests,of A0M0and A4M5mem-brane supports sintered at 1200◦C and the proposed fracture mechanism schematic diagram.For A0M0sintered at 1200◦CL.Zhu et al./Journal of the European Ceramic Society35(2015)711–721717Fig.6.Fracture surface SEM images of the A0M0membrane supports sintered at various temperatures:(a)A0M0—1100◦C,(b)A0M0—1200◦C,(c) A0M0—1300◦C and(d)A0M0—1400◦C.(Fig.8a),most of the fractures upon failure occur from larger glassy phase regions between partially-sintered mullite crystals (as those indicated by red circles in the fracture mechanism schematic diagram made using CATIA software).The frac-ture is completely intergranular,which absorbs lower fracture energy during strength test because of lower intrinsic strength of glassy phase(see Fig.2c).Due to the addition of MoO3and AlF3,open porosity becomes higher,while there is also a sig-nificant change in the microstructure of the fabricated mullite membrane support,which is entirely composed ofinterlocked Fig.7.Fracture surface SEM images of the A4M5membrane supports sintered at various temperatures:(a)A4M5—1100◦C,(b)A4M5—1200◦C,(c) A4M5—1300◦C and(d)A4M5—1400◦C.718L.Zhu et al./Journal of the European Ceramic Society 35(2015)711–721Fig.8.Freshly fractured surface SEM images (left)and fracture mechanism schematic diagram (right)of the A0M0(a)and A4M5(b)membrane supports sintered at 1200◦C after biaxial flexural strength tests.mullite whiskers without the presence of glassy phase.The inter-grown rod-like mullite crystals (as those indicated by the circles in Fig.8b)could impart good mechanical strength and structure rigidity to the porous mullite support.These inter-locked mullite whiskers are expected to exhibit excellent mechanical properties such as high strength and high modulus since they absorb much higher fracture energies than partially-sintered glassy phase par-ticles (see Fig.2c),consequently resulting in an enhancement in mechanical strength.19,22Possible bridging crack and pull-out of bonded mullite whiskers in aligned way also contribute to this enhancement in strength,31as well indicated in Fig.8b.In summary,with addition of MoO 3and AlF 3,formation of more inter-locked mullite whiskers,which adsorb more energy during fracture,is responsible for the improvement in open porosity of A4M5and mechanical strength compared with A0M0sintered from 1100to 1400◦C.Besides,possible bridg-ing crack and pull-out of bonded mullite whiskers in aligned way also contribute to this strength enhancement.3.6.Water permeance across membrane supportsWater flux (Fig.9a)of A0M0and A4M5increases with trans-membrane pressure as well as sintering temperature.In all cases,the water flux increases linearly with transmembrane pressure,which indicates that pressure difference is the only driving force for the permeation of water.When the transport mechanism fol-lows the viscous flow model,the flux versus transmembrane pressure plot should be expressed as a straight line which coin-cides with the origin (Darcy’s law),32as indicated in this study.Similar trends were also reported for the other porous inor-ganic clay-based membranes.5In Fig.9b,an approximately linear relationship exists between water permeance and aver-age transmembrane pressure,indicating a preferential laminar flow mechanism in the mullite membrane supports.333.7.Nitrogen gas permeance across membrane supportsA pure,non-adsorbing gas flow through a homogeneous porous structure may be described by Knudsen diffusion,vis-cous flow,surface diffusion,dissolution diffusion,or some combination of these processes.The mechanism of gas transport through microporous membrane depends upon the pore size (r )of the membrane relative to the mean free path (λ)of the gas molecule.Knudsen diffusion occurs in small pores where colli-sions of the gas molecules with the pore walls have a significant effect on their movement.Viscous flow describes the situation where the pores are large enough so that the viscosity of the gas controls the flow rate through a porous body.In some cases,permeation may also be enhanced by the reaction of the gas with the pore wall surface,i.e.surface diffusion.When the membrane has pores comparable to the size to the mean free path of the gas molecule,the permeation flux through the membrane can be considered as a combination of Knudsen diffusion and viscous flow.So the permeation of the gas through the porous structure may be modelled by treating Knudsen diffusion and viscous flow as parallel processes,as shown in the following equation 34J =εr τk [2ν/3RTL ]P +εr 2τv [1/8RTLη]¯pP (5)where the flux J of a gas component is a function of:(i)gas properties,such as the gas mean molecular velocity νof the gas and the viscosity of the gas η,and the gas mean molecular velocity νis given byν= 8RT πM(6)where M is the gas molecular mass;(ii )the differential pressure across the membrane P ;(iii)the average pressure within the membrane ¯p ;(iv)the membrane thickness L ;and (v)the pore characteristics:open porosity ε,pore radius r and the tortuosity factor of the pores corresponding to either the Knudsen τk or vis-cous flow τv mechanisms.The tortuosity factors compensate for the pore structure features,which deviate from uniform straight pore structure.The gas permeance of a porous membrane,which is equal to the flux normalized by the pressure difference of the gas across the membrane (J /P ),is given byJ P =εr τk [2ν/3RTL ]+εr 2τv [1/8RTLη]¯p (7)Plotting the gas permeance vs.average pressure yields a straight line of the form:JP=a +b ¯p (8)。

the Power of Farm-to-Table有机食品的魅力All Alice Waters wanted was bread, jam and lettuce that tasted real, with a cup of good coffee or a glass of wine on the side. The founder of Chez Panisse , the California restaurant famous for launching the farm-to-table movement, certainly didn’t plan to start a revolution.Returning to the United States in 1965 after studying . in France, Waters missed the delicious food and community of the little cafés where she spent most of her time. “The United States was a land of frozen food, so eating even just fresh bread and jam was a revelation to me,”says Waters.“And spending time in restaurants with friends was very important to me.”One day, an idea struck Waters that maybe her cooking and sense of community could help her make some money. Believing they could do anything, she and a group of friends raised money, found a house in Berkeley and opened a little restaurant called Chez Panisse in 1971.Most ingredients Waters could find were from industrial farms. They tasted totally different from the ones her parents planted during World War II and the ones she had enjoyed in France. Thus she began a search for suppliers who would grow good ingredients.“I was looking for taste. And I couldn’ t find taste until I met the local organic（有机的）farmers who were growing vegetables for flavor ,” Waters recalls. “I realized that I would be dependent on them for the success of my restaurant.”At firsts the finances were a disaster. If any of the in gredients didn’t taste right, chefs threw them out. Staff had to taste the wine to sell it. That meant thousands of dollars of wine disappeared on a regular basis. People who offered ingredients were given meals in trade.But Chez Panisse had lines out of the front door from the very first night. Waters’ senseof taste and her dedication to making the best food possible kept people coming back. It didn’t take long for the restaurant to catch the attention of foodies（喜爱美食的人）.Throughout its existence, Chez Panisse has earned the highest praise of many critics. It has sometimes been called the best restaurant in America.Waters is not content with staying at home and cooking in her kitchen. In September 2016, she flew to Washington ,D.C., to meet members of Congress（国会）to discuss the benefits of free lunch for all schoolchildren.Many people have called Waters unrealistic over the course of her fight for good food for nearly half a century. Nevertheless, her single-mindedness ended up sparking （引发）a farm-to-table movement. “ She didn’t start Chez Panisse to change the world”said Marion Nestle, a New York University nutrition professor.“But what she did was absolutely r evolutionary. She’ s a force（影响力大的人）and deserves every bit of recognition that comes her way.”（节选自CNN）1. According to the article, Alice Waters started Chez Panisse in order to_______.A. launch a farm-to-table revolutionB. allow all schoolchildren in the United States to have free lunchC. support the local organic farmersD. bring France’s style of cooking and sense of community to her home country2. In the early days of Chez Panisse, finances were a big problem because_______.A. some customers refused to pay for their mealsB. organic vegetables were very expensiveC. Waters put huge emphasis on good food and gratitudeD. the housing rent in Berkeley was very high3. According to the article, Chez Panisse’s success can be attributed to_______.①the great flavor of its dishes②the ideal location of the restaurant③the huge effort Waters puts into her cause④support from several foodiesA.①③B.②④C.①④D.②③4. According to the article, which of the following statements is true?A. Waiters wanted to open a restaurant when she was studying in France.B. Before Chez Panisse , few restaurants in the United States offered fresh food.C. Chez Panisse didn’t become popular until it start ed to use organic vegetables.D. Chez Panisse has been widely recognized as the best restaurant in America.词汇：revolution n. a complete change in ways of thinking, method of working, etc. 变革revelation n. sth. that is surprisingly good, enjoyable or useful 出乎意料的好东西dedication n. hard work or effort sb. puts into a particular activity because they care about it a lot全身心投入语法：One day, an idea struck Waters that maybe her cooking and sense of community could help her make some money.本句中，that引导同位语从句。

阅读预测
阅读机经使用说明：以下阅读预测的内容都是雅思阅读真题的题目或文章主要内容，给出这个写题目就是要求考生提前对其背景有简单的了解。

比如Ambergris （龙涎香），如果考生不没有见过这个单词，看文章自然是云山雾罩；如果你提前了解了Ambergris（龙涎香）这个东西，知道龙涎香是抹香鲸科动物的肠内分泌物制成的香料，你在阅读的时候就能大大提高效率和理解能力，为你的阅读加分！所以，你只需要简单查阅百度百科，了解这些奇怪的概念并认识其英文名称，即可。

摘桑葚英语作文Amidst the verdant meadows and lush greenery of spring, the mulberry trees stand tall, their branches laden with juicy, purple fruits. The excitement of plucking mulberries is an unforgettable experience, filled with joy, laughter, and the sweet taste of summer.As the sun rose, casting its warm glow over the orchard, I set out on a mission to gather the ripened mulberries.The air was filled with the sweet scent of the fruits, a tantalizing aroma that whetted my appetite. The branches of the mulberry trees were laden with clusters of plump,purple berries, their skins glistening in the morning sun.I carefully navigated the maze of branches, reachingout to pluck the ripest berries. Each berry was a smallburst of flavor, its juice staining my fingers a deep purple. The taste was a blend of sweetness and tartness, a unique flavor that seemed to capture the essence of summer. As I plucked, I couldn't help but notice the beauty of the orchard. The mulberry trees were surrounded by avariety of flowers and plants, each adding a touch of colorto the landscape. Butterflies flitted among the blossoms, and birds sang their morning songs. It was a serene and peaceful scene, one that filled me with a sense of contentment and joy.The hours passed quickly as I immersed myself in the task of plucking mulberries. I filled my basket with the purple treasures, my heart filled with the satisfaction of a successful harvest. As the sun began to descend, casting long shadows over the orchard, I knew it was time to return home.Back at home, the mulberries were washed and prepared for various treats. Some were eaten fresh, their juices dripping down my chin and staining my lips. Others were used to make jam, a sweet and tangy spread that was perfect on toast or pancakes. The mulberries also became the star ingredient in a delicious pie, its purple hue and fruity flavor a welcome addition to our evening dessert.The experience of plucking mulberries was not just about the fruits themselves; it was about the journey, the connection with nature, and the joy of discovery. It was a reminder of the simple pleasures in life, the ones that areoften overlooked in our busy schedules. As I sat back and enjoyed the fruits of my labor, I realized that the sweetness of the mulberries was not just in their taste,but in the memories and experiences they brought to my life. **摘桑葚：一场愉快的冒险**在春天生机盎然的草地和郁郁葱葱的绿意中，桑树挺拔地矗立着，树枝上挂满了汁水四溢的紫色果实。

高二测试题制作希腊烤羊排配柠檬草英语作文Greek Style Grilled Lamb Chops with LemongrassGrilled lamb chops infused with the traditional flavors of Greece are a delightful and aromatic dish that is perfect for any occasion. The combination of tender lamb, fragrant herbs, and zesty lemon creates a harmonious symphony of flavors that will tantalize your taste buds and transport you to the sunny shores of the Mediterranean.To begin, gather your ingredients. You will need fresh lamb chops, garlic, olive oil, lemon juice, oregano, rosemary, salt, and pepper. For a unique twist, we will be incorporating lemongrass into the marinade to add a subtle citrusy note that complements the rich lamb perfectly.Start by preparing the marinade. In a bowl, combine the minced garlic, olive oil, lemon juice, oregano, rosemary, salt, pepper, and finely chopped lemongrass. Mix well to ensure that the flavors are evenly distributed.Next, place the lamb chops in a shallow dish and pour the marinade over them, making sure to coat each chop thoroughly. Cover the dish and refrigerate for at least two hours to allow the flavors to meld together and the meat to tenderize.Once the lamb chops have marinated, it's time to fire up the grill. Preheat your grill to mediumhigh heat and lightly oil thegrates to prevent sticking. Remove the lamb chops from the marinade and shake off any excess before placing them on the grill.Grill the lamb chops for about 34 minutes per side, or until they reach your desired level of doneness. Remember to baste the chops with any remaining marinade while grilling to keep them moist and flavorful.As the lamb chops cook, you will be greeted with the savory aroma of garlic, herbs, and lemongrass wafting through the air. The sizzle of the meat on the grill and the gentle charring of the edges will only serve to whet your appetite further.Once the lamb chops are done, remove them from the grill and let them rest for a few minutes to allow the juices to redistribute. Serve the chops hot, garnished with a sprig of fresh rosemary and a wedge of lemon for an extra burst of citrus.With their tender texture, bold flavors, and tantalizing aroma, these Greekstyle grilled lamb chops with lemongrass are sure to be a hit at your next gathering. Transport your taste buds to the sundrenched Mediterranean with this delectable dish that celebrates the best flavors of Greece. Enjoy!。

莫来石的低温合成与结构研究刘从华1,2,邓友全1,黄　3,李　强3,高雄厚2,谭争国2(1.中国科学院兰州化学物理研究所,兰州730000;2.中国石油兰州石化公司石油化工研究院,兰州730060;3.中国石油兰州石化公司催化剂厂,兰州730060)摘要　通过在高岭土中引入质量分数为1%～5%的钒以后,在700℃左右的较低温度下观察到莫来石相的生成,并结合酸、碱抽提反应过程制得较纯的莫来石.进一步研究了低温莫来石点阵参数的测定方法,发现低温钒-莫来石的晶胞体积比常规的高温莫来石大,表明钒进入了莫来石的骨架结构.另外,低温莫来石的形成动力学可表述为钒-高岭石低温共熔体迁移过程.关键词　高岭石;钒;莫来石;晶胞体积;低温共熔体中图分类号　O 612 文献标识码　A 文章编号　0251-0790(2003)04-0698-05收稿日期:2002-07-11.联系人简介:邓友全(1957年出生),男,研究员,博士生导师,从事环境催化与清洁催化工艺研究.E-mail :yd eng@ 莫来石由于具有优良的孔隙性以及耐高温和绝缘等而被广泛应用于陶瓷、冶金、半导体和石油化工等领域[1～3].合成莫来石的方法主要有电熔法和烧结法.电熔法一般以工业氧化铝和硅石为原料,其最大缺点是耗电量大、操作条件苛刻.关于烧结法合成莫来石的报道较多,按所用原料性质可分为无机硅铝凝胶法、有机硅铝凝胶法和矿物相变法.常规烧结法制备莫来石的相变反应温度在1000℃以上,对设备材质要求苛刻,能耗高.因此,寻求低温合成莫来石的方法对陶瓷和石油化工等领域具有重要意义.在莫来石合成中引入V ,Fe ,Ti ,Mg 和M n 等杂原子可以降低莫来石的形成温度.Oakley 等[4]在高岭土中引入少量钒以后,在900℃观察到了莫来石相的形成.本文报道了在钒-高岭土的相变体系中,在700℃左右的低温下观察到了钒-莫来石相的形成,并结合酸、碱抽提处理工艺可以获得纯度高达85%的钒-莫来石.利用XRD 研究了钒对低温莫来石结构的影响,测定了低温莫来石的晶胞参数,探讨了钒-莫来石在低温条件下的形成过程.1　实验部分1.1　原料与仪器YL 高岭土(工业品,陕西榆林),质量分数:Al 2O 343.3%,Fe 2O 30.7%,Na 2O 0.1%,K 2O 0.4%,平均粒径3.6μm;钒酸铵(分析纯,北京化工厂),盐酸和氢氧化钠(分析纯,西安化学试剂厂).用日本理学公司D /m ax -3C X 射线衍射仪进行物相分析,以纯硅粉作内标.点阵参数的测定按X 射线衍射仪配置的点阵参数精细化程序,采用最小二乘法进行分析;用JEM-1200EX /S 电镜分析仪进行晶体形貌分析.1.2　实验和测试方法按所需比例将偏钒酸铵与高岭土混合、研磨均匀,于120℃下干燥,在不同温度下焙烧处理.按一定比例将焙烧后的高岭土加入到质量分数15%的盐酸溶液中,于50～90℃反应2h ,然后过滤、洗涤;将滤饼加入到质量分数15%的氢氧化钠溶液中,于80～95℃反应2h 后,过滤,洗涤,干燥[5].2　结果与讨论2.1　钒-莫来石的合成高岭石的化学组成为Al 4(O H)8Si 4O 10,属三斜晶系,其结构由SiO 4四面体和AlO 6八面体交错的层间构成.关于高岭土相变方面的研究报道很多,榆林(YL)高岭土的相变过程如图1所示.Y L 高岭Vo l.24高等学校化学学报　No.4　2003年4月 CHEM IC AL J OU RN AL OF C HINE SE UN IV ERS ITIES 698～702土的原晶相部分主要是高岭石相,基本不含石英和伊梨石等杂质.经过焙烧,在600℃左右转变成偏高岭土,晶相衍射峰基本消失,表明偏高岭土以无定形状态存在.随着焙烧温度的升高,直到850～900℃,未发现有新的晶相生成.温度升至950℃时,可以看出有少量尖晶石相生成.含有外加氧化钠(质量分数约3.0%)的样品在950℃形成了少量的莫来石相.高岭土载有不同含量的钒,于750℃焙烧2h ,XRD 物相分析表明,当钒质量分数少于0.5%时,无明显新晶相生成;当w (V )= 1.5%时,有少量新晶相生成;当钒质量分数升至 3.0%～ 5.0%时,这种新晶相大量生成.通过与PDF 卡片15-776对比(图2谱线a ),证实这种未知新晶相为莫来石相.进一步研究表明,即使在660～700℃时,也可在钒-高岭土混合体系中观察到莫来石的生成.Fig .1　XRD patterns of YL kaolin calcined at diff erenttemperaturesa .Hyd ro -kaolin ;b .600℃,1h ;c .850℃,1h ;d .900℃,1h ;e .950℃,1h ;f .950℃,1h (con-taining mas s fraction 3.0%Na 2O).Fig .2　XRD patterns of calcined kaolin through process of acid and caustic leaching a .Calcin ed kaolin [w (V )= 5.0%,750℃,2h ];b .after acid leaching;c .after acid and caustic leach ing.一般通过粘土矿(如高岭土)高温转化法难以制得较纯的莫来石.这是因为,一方面,粘土的天然化学组成难以达到莫来石的组成要求,因而只能在粘土中部分形成莫来石;另一方面,粘土经过高温(>1000℃)焙烧,其中的氧化铝被彻底钝化,丧失了与酸或碱的反应活性,因此难以将莫来石从高温焙烧粘土中提纯分离.从上面的讨论可知,在钒-高岭土体系中,在660～700℃的低温下也能生成莫来石.由于在此温度下高岭土中的氧化铝被活化了,故对酸具有反应活性.同时,由于在该温度下形成了莫来石,高岭土中的氧化硅显然也得到了充分活化.在这种钒-高岭土体系中,于上述温度焙烧形成莫来石后,剩余的铝和硅同时得到充分活化,它们可分别与酸和碱发生反应而被分离出来,从而可制得较纯的莫来石,这种推测在实验中得到了证实(图2).载有钒质量分数5%的高岭土经过750℃,2h 处理形成较大量的钒-莫来石相(图2谱线a ),另外还生成了方英石(2θ=21.9°).将上述样品用酸处理,莫来石相的含量有所提高(图2谱线b ),这是因为酸处理将样品中的活性氧化铝分离出去,从而提高了样品中莫来石的相对含量.继续用碱处理该样品,可明显看到样品中方英石相消失,样品中大量的活性氧化硅与碱性物质发生反应而被分离开,剩余部分则基本上都变成莫来石相,莫来石质量分数可以达到85%以上(图2谱线c ).按本实验制备的低温莫来石(样品A )和常规硅铝凝胶法制备的高温莫来石(样品B )的SEM 形貌特征如图3所示.低温合成的莫来石晶粒呈明显的积聚状态,而高温合成的莫来石呈分散状态.2.2　莫来石形成过程的研究高岭土相变形成莫来石的动力学已有文献报道[6],在900～1000℃出现的尖晶石是形成莫来石的速控步骤.随着焙烧温度的升高,Si —O 和Al —O 键断裂,铝的配位数由4变成8,在1200℃左右形成莫来石.在1250～1300℃莫来石由立方构型转化为正交构型.也有文献报道[6],引入Cr 3+等离子,可以有效地降低硅铝母体的莫来石反应的活化能,但反应温度都在1000℃以上.对于V 5+离子导致的低温莫来石反应的动力学过程尚未见报道.钒对高岭土相变过程中莫来石生成量的影响见图4.图4表明,钒含量较低时,莫来石的形成量很少;随着钒含量的增加,莫来石的生成量迅速增加;当钒质量分数达到5%时,莫来石质量分数增加至699N o.4刘从华等:莫来石的低温合成与结构研究 Fig .3　The SEM images of mullites prepared by dif ferent methods (A )Ph as e tran sformation of m ullite p repared at a low temperatu re via acid and caus tic leaching ;(B)ph as e tan sformation of silica-alumina gel p repared at a hightemperature.Fig .4　Ef f ect of mass f raction of vanadium on mullitef ormation f rom kaolin calc ined at 750℃f or 2h 20%以上.如图5所示,在750℃下焙烧10～15min,也有大量莫来石生成.随着焙烧时间的延长,莫来石增加并不明显,但伴随有大量方英石(晶面衍射2θ=21.9°)生成.这表明,在一定的钒含量和焙烧温度下,高岭石的莫来石化时间大大缩短.从前面的讨论可知,这种伴生的方英石也不同于常规合成的方英石,它能由碱(如氢氧化钠)抽提出来.当焙烧温度降至660℃时,也可形成莫来石相(图6).若再降低焙烧温度,就难以在XRD 图上检测到莫来石相的生成.V 2O 5的熔点为670℃,与含钒高岭土的低温莫来石化温度极为相近,这种现象并非偶然.另外,当高岭土中的钒质量分数降至2.5%时,也可以观察到类似的现象,不过此时生成的莫来石量较少.Fig .5　XRD patterns of kaolin containing vanadiumcalcined at 750℃for diff erent t imeCalcinating time /h :a .1/4;b .0.5;c . 1.0;d . 2.0.Fig .6　XRD patterns of kaolin containing 5.0%vanadium at diff erent temperatures for 2h Calcinating tem prature /℃:a .540;b .660;c .700;d .750;e .800.总之,有钒存在下,高岭土的莫来石化反应是一个低温熔变过程,当焙烧温度达到V 2O 5的熔点时,V 2O 5与偏高岭土形成低温共熔体,这是一个快速反应步骤.在低温共熔体中Si —O 和Al —O 键发生断裂、迁移和重组,并在局部达到莫来石的组成要求,这是相变反应的控速步骤,随后便快速形成莫来石相.在形成莫来石之前并不经过尖晶石相的形成过程,对于纯高岭土的相变,则往往伴随着尖晶石相和莫来石相的同时生成.2.3　钒-莫来石的点阵参数莫来石的典型晶体结构为正交晶系.在高岭石的高温相变中可以观察到立方莫来石相过渡态,随着焙烧温度的升高,立方构型转化为稳定的正交晶系构型,也有人用有机硅铝试剂合成了假四方莫来700 高等学校化学学报V ol.24石[7].外加元素可引起莫来石a 0,b 0和c 03个晶轴的变化,但并不改变其正交晶体对称性.在实验中采用最小二乘法按下述原理测定了钒-莫来石的点阵参数.正交晶系的点阵参数与晶面衍射指数之间的关系为1d =h 2a 0+k 2b 0+l 2c 0,　2d sin θ=λ式中h ,k 和l 为某一晶面的衍射指数,a 0,b 0和c 0为晶体的点阵参数(nm ),d 为对应于hkl 的晶面间距(nm),θ为对应于hkl 的晶面衍射角(°),λ为Cu K T 辐射的特征波长(0.15178nm).选择莫来石晶相的某几组晶面衍射峰,代入相应的晶面衍射指数和晶面间距,组成联立方程组,就可获得正交晶系的点阵参数.晶胞体积(V )可由式V =a 0 b 0 c 0计算.按照D /max -3C X 射线衍射仪配置的点阵参数精细化程序,选择最小二乘法分析钒-莫来石的点阵参数.直接利用PDF 卡片15-776中有关纯莫来石的衍射峰数据,考察选择不同衍射峰对莫来石晶胞参数计算结果的影响(表1).分析过程中每组选择5个衍射峰,一是受分析程序所需最小衍射峰数量的限制,最低不少于5组;二是在不影响计算结果的前提下,尽量少选以缩短分析时间.另外,还必须优选有代表性的强峰.从表1可见,衍射峰的选取对莫来石的点阵参数计算结果的影响很大.通过与PDF 卡片值对比,选择110,210,220,111,121这5组晶面衍射计算的晶胞参数与PDF 卡15-776值相当接近,因此在测定过程中以这5组强峰作为分析依据.虽然包含次强峰(120)组的分析相对误差也很小,但由于当莫来石含量较低时(质量分数小于10%),最强峰与次强峰不易分开,从而严重影响分析结果的准确性,因此舍弃.Table 1　Ef fect of dif f raction peak selections on uint cell parameters of mullite Selection of peaka 0/nmb 0/n mc 0/nm 103V (Unit cell)/nm 3Relatived eviation *(%)110,210,220,111,1210.75510.76880.2883167.36+0.01001,210,220,111,1210.74970.71670.2870165.10- 1.34230,210,220,111,1210.75940.77010.2892169.13+ 1.06120,210,220,111,1210.75460.76870.2881167.09-0.16PDF card 15-7760.75460.76900.2884167.350.00 *Considering th e data in PDF 15-776is correct.按照上述正交晶系点阵参数的测定方法,测定了含有低温钒-莫来石和高温纯莫来石的点阵参数,实验结果见表 2.将钒引入莫来石后,其晶胞体积发生明显变化.随着钒质量分数从 1.5%增加至5.0%,莫来石的晶胞体积不断变大.a 0轴的增幅最为明显,b 0轴略有变化,c 0轴则基本不变.由此可见,钒插入莫来石引起的膨胀过程对a 0,b 0和c 0晶轴是非线性的.钒对莫来石晶胞结构的影响主要在于a 0轴的激烈膨胀[8].这种现象在硅铝凝较法合成莫来石的加热过程中也会发生[6].Schneider [6,7,9]认为a 0以及晶胞体积的增加主要来自于铝氧八面体发生的畸变、旋转和倾斜过程,另外,铝氧四面体的畸变也不能忽略.Table 2　Determinat ion of several mullite ′s unit cell parametersSam plew (Vanadiu m )(%)a 0/nm b 0/nm c 0/nm 103V (Unit cell)/nm 31# 5.00.76050.76930.2896169.432# 3.00.75920.76850.2887168.443# 1.50.75870.76720.2888168.104#00.75460.76880.2884167.31PDF card 15-77600.75460.76900.2884167.35 在高岭土相变过程中引入钒,大大降低了莫来石的形成温度,低温合成的莫来石的晶胞体积的膨胀方式与高温合成的有所不同.当高岭石的钒质量分数达到5%时,样品经过540℃,2h 处理,在X RD 图上看到明显存在V 2O 5晶相.当焙烧温度达到750℃时,V 2O 5已熔化成液体,并与高岭土的硅-铝化合物形成低温共熔体.同时,钒部分取代硅和铝进入所形成的莫来石骨架中,使其被钝化而失去反应活性,这极有可能是半合成裂化催化剂中,高岭土具有抗钒作用的重要原因.由于钒的常见离子(V 5+)半径比Si 4+或Al 3+的大,从而引起莫来石的晶胞体积膨胀.另外,钒在莫来石的骨架中部分占701N o.4刘从华等:莫来石的低温合成与结构研究 据了八面体铝位置,引起铝氧八面体的畸变.同样,硅氧、铝氧四面体也会发生类似的变化.V 2O 5在高岭土相变过程中发生了类似于“矿化剂”的作用.由于Na 2O 熔点较高,含质量分数3%Na 2O 的高岭石的莫来石化温度一般高于950℃(图1),而含有Cr 2O 3的硅铝凝胶母体,也只有在1250℃以上才能生成莫来石相,这时引入离子的矿化作用是较小的[9～11].参　考　文　献[1]　Silverman L. D.,Speronello B.K..E P 15188[P],1985[2]　Vincent S.R ..EP 134770[P],1985[3]　Yamagata M.,Okamoto Y.,Tok ushima K.et al ..JP 02298324[P],1990[4]　Oakley M .J .,Sharp J .H ..Trans .J .Br .Ceram .Soc .[J ],1983,82(5):177—187[5]　LIU Cong-Hua(刘从华),PAN Zhong-Liang (潘仲良),ZHAN G Yong-M ing(张永明).CN 1232803[P],1999[6]　Sch neider H..J .Am.Ceram.Soc.[J],1993,76(11):2896—2994[7]　Sch neider H..J .Am.Ceram.Soc.[J],1988,71(3):C162—C175[8]　Occelli M.L..Catal.Rev.[J ],1991,33(3—4):241—280[9]　Sch neider H ..J .Eu r .Ceram .Soc .[J ],1996,16:211—220[10]　ZHEN G J in-Yu(郑金玉),Q IU Kun-Yuan (丘坤元),W EI Yen(危　岩).Chem.J .Chin ese Universities(高等学校化学学报)[J ],2000,21(4):647—649[11]　W AN G Xing-Yi(王幸宜),W AN Ying (万　颖),LU Guan-Z h ong(卢冠忠).Ch em.J .Chin ese Univ ersities(高等学校化学学报)[J ],2000,21(9):1470—1472Mullite Synthesis at Low Temperature and Its CrystalS tructure CharacterizationLIU Co ng-Hua 1,2,DEN G Yo u-Quan 1*,HU AN G Quan 3,LI Qia ng 3,GAO Xiong -Hou 2,T AN Zheng -Guo 2(nzhou Institute of Chemical Physics ,Chinese Academy of Sciences ,Lanzhou 730000,China ;2.Petrochemical Research Institute ,L anzhou Petrochemical Company of PetroChina ,Lanz hou 730060,China ;3.Catalyst Plant ,L anzhou Petrochemical Company of PetroChina ,Lanzhou 730060,China )Abstract Va nadium -mullite had been surprising ly o bserv ed in the phase transition of kaolin in the presence 1%—5%v anadium at about 700℃,a nd quite a pure va nadium-mullite co uld be o btained through the process of acid &base leaching reactio n a nd sepa ra tio n.In additio n,unit cell pa ram eters o f v arious m ullites w ere especially determined by X RD and the unit cell v olume of va nadium-mullite fo rm ed at a low tempera ture was fo und to be g reater than tha t of the comm on mullite ,which could be deduced that v anadium incorporated into the mullite framew ork.Furthermo re,the reaction process of va nadium-m ullite forma tion could be ex pressed as lo w -melting v anadium -kaolin eutectic transitio n.Keywords Kaolin ;Vanadium ;Mullite ;Unit cell v o lum e ;Eutectic(E d .:V ,X )702 高等学校化学学报V ol.24。

高一测试题制作希腊烤羊排配柠檬酱英语作文Title: Creating a High School Test: Greek Lamb Chops with Lemon SauceCreating a high school test that involves making Greek lamb chops with lemon sauce can be a fun and engaging activity for students to showcase their culinary skills. This assignment not only tests their cooking abilities but also allows them to explore different flavors and techniques in the kitchen.To begin with, the students can be given a list of ingredients required to make the dish. This can include lamb chops, olive oil, garlic, oregano, lemon juice, and other seasonings. They should also be provided with a recipe detailing the steps involved in preparing the lamb chops and lemon sauce.The test can be divided into several sections to assess the students' understanding of the cooking process. They can be asked to demonstrate their knife skills by properly trimming the lamb chops and mincing the garlic. Additionally, they can be evaluated on their ability to marinate the meat effectively, ensuring it is wellseasoned and flavorful.Once the lamb chops are ready to be cooked, the students can be tasked with grilling or pansearing them to achieve the desired level of doneness. This step allows them to practice their cooking techniques and timing, ensuring that the lamb chops are cooked to perfection.The final component of the test involves making the lemon sauce to accompany the lamb chops. Students should be able to follow the recipe accurately, combining the lemon juice, olive oil, and spices to create a tangy and savory sauce that complements the flavors of the meat.Overall, creating a high school test centered around making Greek lamb chops with lemon sauce is a creative way to engage students in the culinary arts. It allows them to apply their cooking skills in a practical setting while also encouraging experimentation and creativity in the kitchen. By completing this test, students can gain confidence in their abilities and develop a deeper appreciation for the art of cooking.。

初一测试题制作希腊烤羊肩配橄榄油英语作文For our firstyear test, we were tasked with creating an English essay on the topic of Greekstyle roasted lamb shoulder with olive oil. This culinary theme presented a unique challenge, blending the art of food with the craft of language. As I delved into the task, I found myself exploring the rich traditions of Greek cuisine and the significance of olive oil in theirculinary heritage.Greekstyle roasted lamb shoulder is a dish that embodies the essence of Greece's gastronomic culture. The succulent meat, marinated in a blend of herbs and spices, carries with it the flavors of the Mediterranean. The slow roasting process allowsthe flavors to meld together, creating a dish that is bothtender and bursting with taste.Central to this dish is the use of olive oil, a staple in Greek cooking. Olive oil not only adds a distinctive flavor tothe lamb but also plays a crucial role in Mediterranean cuisine as a whole. Its health benefits and versatility in cooking makeit a prized ingredient in Greek households and restaurants alike. The golden hue of the oil glistens on the lamb shoulder, enhancing its appeal and taste.As I crafted my essay, I reflected on the culturalsignificance of this dish. Greekstyle roasted lamb shoulder isnot simply a meal; it is a symbol of community and celebration.In Greece, sharing a meal with loved ones is a cherished tradition, and the preparation of food is an expression of love and care. This dish, with its rich flavors and aromas, evokes a sense of togetherness and joy.In conclusion, writing about Greekstyle roasted lamb shoulder with olive oil has been a delightful experience. It has allowed me to appreciate the artistry of Greek cuisine and the importance of food in culture. This task has not only tested my language skills but has also deepened my understanding of the role that food plays in bringing people together. I look forward to further exploring the intersection of food and language in my future writing endeavors.。

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每段对话仅读一遍。

例：How much is the shirt?A. £ 19. 15.B. £ 9. 18.C. £ 9. 15.答案是C。

1．How does the girl probably feel about her job?A．Bored and tired. B．Interested and excited. C．Relaxed and relieved. 2．How does the woman respond?A．She is angry. B．She is satisfied. C．She forgives the man. 3．Where does the conversation probably take place?A．At the hotel. B．At the customs. C．At the cinema.4．What is the woman doing?A．Renting an apartment. B．Confirming an appointment. C．Making a complaint. 5．How does the woman feel finally?A．Defeated. B．Depressed. C．Encouraged.第二节（共15小题，每小题1.5分，满分22.5分）听下面5段对话或独白。