Carbon Monoxide in type II supernovae
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燃料电池双极板超亲水碳涂层非晶碳耐蚀石墨微晶
导电层氧化硅亲水层
燃料电池双极板是燃料电池的核心组件之一,它承担着将氢气和氧气转化为水并释放能量的重要作用。
双极板通常由多层材料构成,其中包括超亲水碳涂层、非晶碳耐蚀层、石墨微晶导电层和氧化硅亲水层。
超亲水碳涂层是位于双极板表面的一层材料,具有非常高的亲水性,可以使水分子快速均匀地分布在整个双极板表面,从而提高氧气的传输效率,并降低气泡的产生。
非晶碳耐蚀层是在超亲水碳涂层下方的一层材料,主要起到防止双极板受到腐蚀的作用。
由于燃料电池中存在酸性环境和高温条件,这一层材料需要具备良好的耐蚀性能,以保证双极板的长时间稳定运行。
石墨微晶导电层是位于非晶碳耐蚀层下方的一层材料,具有优异的导电性能,可以有效地传导电子,将氧气的电荷转移至双极板表面。
氧化硅亲水层是位于石墨微晶导电层下方的一层材料,具有良好的亲水性能,可以吸附和传输水分子,从而帮助氢气和氧气的反应进行顺利。
此外,氧化硅层还可以起到隔离作用,防止氢气和氧气发生非预期的反应。
总体来说,燃料电池双极板的设计与材料选择都非常关键,不同的材料层次有各自的功能,并共同协作以实现高效的能量转
化和稳定的电池运行。
小学上册英语能力测评(含答案)考试时间:90分钟(总分:100)B卷一、综合题(共计100题共100分)1. 选择题:What do we call a baby dog?A. KittenB. PuppyC. CalfD. Chick答案:B2. 听力题:A _______ can help visualize the concept of pressure in liquids.3. 选择题:What instrument is used to measure temperature?A. BarometerB. ThermometerC. SpeedometerD. Altimeter4. 填空题:The _____ (根茎) stores nutrients for the plant.5. 填空题:The _____ (大象) has a great memory.6. 选择题:What is the opposite of "hot"?A. WarmB. ColdC. CoolD. Dry答案:BThe sun is very ________ (热) in the summer.8. 选择题:What do you call a person who plays a musical instrument?A. MusicianB. ArtistC. PerformerD. Singer答案:A9. 填空题:We can see many ________ (野生动物) in the national park.10. 听力题:The ______ is a vital part of agriculture.11. 听力题:I enjoy _____ (做饭) new recipes.12. 听力题:A _______ provides food and shelter for animals.13. 选择题:How many players are on a team in American football?A. 10B. 11C. 12D. 1314. 选择题:What do you call the act of moving quickly on foot?A. WalkingB. RunningC. JumpingD. Dancing答案: B15. 填空题:The parrot repeats everything it _________. (听到)16. 填空题:The cake is _______ (刚出炉).The chemical formula for ammonium thiocyanate is _______.18. 听力题:Chemical reactions often require _____ to start.19. 填空题:The _______ (Taj Mahal) is a famous mausoleum located in India.20. 填空题:My teacher is very __________ (支持性).21. 听力题:The _____ belt is located between Mars and Jupiter.22. 填空题:A whale is a giant _______ that swims in the ocean.23. 选择题:What is the name of the famous ship that is a symbol of love?A. TitanicB. Love BoatC. Queen MaryD. USS Enterprise答案: A24. 听力题:The anemonefish lives in a ____.25. 听力题:I have a ___ (story) to share.26. 填空题:The kangaroo carries its baby in its ______ (袋子).27. 听力题:I like to watch ______ (nature) documentaries.28. 选择题:What is the primary color of the ocean?A. GreenB. BlueC. RedD. YellowWhat do we call the time when the sun sets?A. DawnB. NoonC. DuskD. Midnight答案:C30. 填空题:The ________ (山脉) is very long and stretches across several countries.31. 填空题:Plants are vital for our _____ (生存).32. 填空题:My pet hamster loves to run in its ______ (笼子).33. 选择题:Which animal is known as " man's best friend"?a. Catb. Dogc. Birdd. Fish答案:b34. 听力题:The chemical symbol for oxygen is ________.35. 听力题:Sulfuric acid is a common industrial ________.36. 听力题:My dad is very ________.37. 选择题:What is the smallest continent?A. AsiaB. AfricaC. AustraliaD. Europe38. 选择题:What do you call a book about someone's life?A. NovelB. BiographyC. FictionD. Dictionary答案:B39. 填空题:The ______ (小鸟) learns to fly after a few weeks in the ______ (巢).40. 填空题:The dog enjoys going for long _______ (散步).41. 填空题:I have a kind _____ (朋友).42. 选择题:What do you call a baby dog?A. PuppyB. KittenC. CalfD. Chick答案: A43. 选择题:What is the capital city of Russia?A. MoscowB. St. PetersburgC. KazanD. Novosibirsk答案: A44. 听力题:A supernova is the death of a ______.45. 填空题:My teacher makes learning __________ (快乐的).46. 听力题:The ________ (goal) is achievable.47. 填空题:A dolphin is a playful ______ (动物).48. 听力题:The _____ (teacher/student) is helpful.49. 听力题:The cake is very ________.The weather is ________ today.51. 填空题:I like to visit the ______ (农场) and see all the animals. Feeding the chickens is always a fun activity.52. 听力题:Some animals, like bears, prepare for winter by __________.53. 填空题:A ______ (马) can be ridden in races.54. 选择题:What do you call a large, flightless bird?A. SparrowB. OstrichC. EagleD. Crow答案: B55. 选择题:Which planet is known as the Red Planet?a. Venusb. Marsc. Mercuryd. Neptune答案:B56. 填空题:The ________ has colorful petals that bloom in spring.57. 填空题:The _____ (花瓣) of the flower are colorful and attract insects.58. 填空题:This ________ (玩具) helps me appreciate art.59. 填空题:I have a toy _______ that goes fast and makes cool sounds.60. 填空题:My ________ (玩具名称) is a fun way to practice teamwork.My cousin is a talented ____ (guitarist).62. 听力题:She has a new ________.63. 选择题:Which animal is known for its long neck?A. LionB. GiraffeC. ElephantD. Zebra答案: B64. 选择题:What is the longest river in the world?A. AmazonB. NileC. MississippiD. Yangtze65. 填空题:A small ___ (小袋鼠) hops around in Australia.66. 选择题:What do you call a story that is made up?A. FactB. FictionC. Non-fictionD. Biography67. 听力题:An indicator changes color in the presence of an ______.68. 填空题:The ______ (植物的利用方式) is diverse and impactful.69. 选择题:Which animal is known for its ability to change colors?A. ChameleonB. FrogC. SnakeD. Lizard答案:AA ____ enjoys basking in the sun on warm days.71. 填空题:My favorite fruit is ________ (苹果).72. 选择题:What do we call a person who studies sociology?A. SociologistB. PsychologistC. AnthropologistD. Philosopher73. 选择题:What is the term for a young female rabbit?A. BunnyB. KitC. PupD. Leveret答案:B74. 听力题:I like to play ______ (basketball) with my friends.75. 听力题:The process of making chocolate involves _______ fermentation.76. 听力题:The _____ (cloud) looks fluffy.77. 听力题:She is a good ________.78. 听力题:The process by which plants make their food is called ______.79. 听力题:She loves to _______ (dance) at parties.80. 选择题:What do you call the liquid that comes from trees?A. GumB. SyrupC. SapD. Juice答案:CI play _____ (棋) with my dad.82. 听力题:The cake is _______ (decorated) with fresh fruit.83. 选择题:What do you call a young llama?A. CalfB. FoalC. KidD. Cria答案:D84. 填空题:The __________ is a large reservoir in the United States. (胡佛水坝)85. 听力题:The _____ shows the different phases of the moon.86. 选择题:What do you call a person who catches fish?A. FishermanB. FarmerC. HunterD. Gatherer答案:A87. 选择题:What is the color of a peach?A. PinkB. OrangeC. YellowD. Brown88. 听力题:The chemical formula for carbon monoxide is _____.89. 选择题:What is the name of the famous ice cream brand?A. Häagen-DazsB. Ben & Jerry'sC. Baskin-RobbinsD. All of the above答案: D. All of the aboveA _____ (花园) is a beautiful place to relax and enjoy nature.91. 听力题:The chemical formula for baking soda is _______.92. 选择题:Which instrument has keys and is black and white?A. ViolinB. TrumpetC. PianoD. Guitar答案:C93. 听力题:I like ________ (collecting) stickers.94. 填空题:I love to explore ________ (山脉) during vacations.95. 听力题:She is painting a ___. (mural)96. 听力题:The chemical formula for mercury(II) chloride is _____.97. 听力题:The _____ (game/toy) is fun.98. 填空题:The turtle carries its _______ (壳) everywhere.99. 听力题:A dolphin is a smart ______.100. trial Revolution started in __________ (英国). 填空题:The Iron。
科技词汇常用科技词汇一、物理学1. 功率power2. 稳定性stability3. 载荷load4. 概率probability5. 势能potential energy6. 动量momentum7. 电流current8. 直流电direct current9. 交流电alternating current10. 电压voltage11. 变压器transformer12. 静态的static13. 动态的dynamic14. 薄膜thin film15. 量子理论quantum theory 16. 黑洞black hole17. 参数parameter18. 变量variable19. 因子factor20. 乘法、繁殖multiply21. 光学optics22. 合金alloy23. 陶瓷ceramics24. 不对称asymmetry25. 摩擦friction26. 流体力学fluid mechanics27. 重力,地心引力gravity28. work 做功29. 辐射radiation30. 杠杆作用,杠杆效率leverage31. 声纳sonar32. 分贝decibel33. 漂白bleach34. 锅炉boiler35. 沸点boiling point36. 晶体管transistor37. 容量capacity38. 离心力centrifugal force39. 向心力centripetal force40. 电荷charge41. 带电粒子charged particle42. 公式formula43. 等式equation44. 净化器cleaner45. 系数coefficient46. 生化biochemistry47. 压缩compression48. 传导性conductivity 49. 导体conductor50. 常数constant51. 含量content52. 转化conversion53. 冷却器cooler54. 自动化automation55. 临界点critical point56. 晶化crystallize57. 纹理texture58. 电磁辐射electromagnetic radiation59. 中子neutron60. 统计学statistics61. 等离子plasma62. 奇点singularity63. 湿度humidity64. 频率frequency65. 频谱frequency spectrum66. 动力学dynamics67. 力学mechanics68. 重心center of gravity69. 撞击,冲击impact70. 电力系统power system71. 绝缘insulation72. 磁场magnetic field73. 放电discharge74. 断电,停电blackout75. 放射性的radioactive76. 分子molecule77. 金属metal78. 钙calcium79. 二氧化硫sulfur dioxide80. 氢弹H-bomb81. 原子atom82. 核nucleus 83. 暗物质dark matter84. 零点能zero energy85. 发动机motor86. 磁暴magnetic storm87. 超新星Supernova88. 相对论theory of relativity89. 大爆炸理论Big Bang Theory100. 光年light year 101. 紫外光UV (ultraviolet) radiation 102. 红外线infrared ray103. 可见光visible light104. 混沌chaos 105. 波长wavelength106. 电极electrode 107. 保险丝,熔丝fuse 108. 波谱,光谱spectrum109. 泵pump110. 属性property 111. 特征characteristic 112.负极negative pole.113. 正极positive pole二、数学1. 定理theorem2. 计算calculation3. 运算operation4. 假设hypothesis, hypotheses (pl.)5. 命题proposition6. 统计statistics7. 平均数average8. 加权平均数weighted average9. 方差variance10. 标准差standard deviation11. 比例propotion 12. 百分比percent13. 百分点percentage14. 百分位数percentile15. 排列permutation16. 组合combination17. 图表graph18. 条形统计图bar graph19. 柱形统计图histogram20. 曲线统计图curve diagram21. 扇形统计图pie diagram22. 常量constant23. 变量variable24. 算术arithmetic25. 和sum26. 差remainder27.乘times (prep.), multiply (v.),multiplication (n.)28. 乘数multiplicator29. 积product30. 商quotient31.等于equals, is equal to, is equivalent to32. 整数integer33. 偶数even numbers34. 奇数odd numbers35. 小数decimal 36. 小数点decimal point37. 分数fraction38. 分子numerator39. 分母denominator40. 比ratio41. 正positive42. 负negative43. 零null, zero, nought, nil44. 十进制decimal system45. 二进制binary system46. 十六进制hexadecimal system47. 四舍五入round48. 下舍入round down49. 上舍入round up50. 代数algebra51. 一次方程simpleequation52. 二次方程quadratic equation53. 对数logarithm54. 开方evolution, extraction55. 二次方根,平方根square root56. 三次方根,立方根cube root57. 逻辑logic58. 集合(集)set59. 映射mapping60. 元素element61. 子集subset62. 全集universe63. 交集intersection64. 并集union65. 逻辑logic66. 原命题original proposition67. 充分条件sufficient condition 68. 必要条件necessary condition 69. 充要条件sufficient and necessarycondition70. 函数function71. 自变量argument72. 定义域domain, field of definition73. 区间interval74. 对数logarithm75. 最大值maximum76. 最小值minimum77. 周期period78. 最小正周期minimal positive period79. 周期函数periodic function80. 常量constant81. 变量variable82. 周期性periodicity83. 微积分calculus84. 实数real number85. 虚数imaginary number86. 矩阵matrix87. 几何geometry88. 点point89. 线line90. 面plane91. 体solid92. 线段segment93. 射线radial94. 平行parallel95. 相交intersect96. 角angle97. 角度degree98. 锐角acute angle99. 直角right angle 100. 钝角obtuse angle101. 三角形triangle 102. 锐角三角形acute triangle103. 直角三角形right triangle104. 直角边leg 105. 斜边hypotenuse 106. 勾股定理Pythagorean theorem 107. 钝角三角形obtuse triangle108. 正弦定理sine theorem109. 余弦定理cosine theorem110. 矩形rectangle 111. 菱形diamond 112. 正方形square 113. 梯形trapezoid 114. 五边形pentagon 115. 六边形hexagon116. 多边形polygon 117. 圆circle118. 圆心centre(BrE), center(AmE)119. 半径radius 120. 直径diameter 121. 圆周率pi122. 弧arc123. 半圆semicircle 124. 扇形sector 125. 椭圆ellipse 126. 圆周circumference127. 周长perimeter 128 面积area129. 立方体cube 130. 多面体polyhedron131. 棱锥pyramid 132. 旋转rotation 133. 轴axis134. 圆锥cone 135. 圆柱cylinder 136. 球sphere137. 半球hemisphere 138. 表面积surface area139. 体积volume 140. 坐标系coordinates141. 坐标轴x-axis, y-axis, z-axis142. 横坐标x-coordinate143. 曲线curve 144. 正弦曲线sine curve145. 余弦曲线cosine curve146. 坐标法method of coordinate147. 解析几何analytic geometry 148. 标准方程standard equation 149. 一般方程general equation 150. 参数方程parameter equation 151. 参数parameter 152. 椭圆ellipse 153. 焦点focus, focal points三、化学1. 二氧化碳carbon dioxide2. 易燃的inflammable3. 可燃的combustible4. 化学仪器chemical apparatus5. 蒸馏distill6. 蒸馏水distilled water7. 催化剂catalyst8. 盐水brine9. 气泡bubble10. 比例ratio11. 酸acid12. 化学组成chemical composition13. 化合物chemical compound14. 化学元素chemical element15. 化学反应chemical reaction16. 化学药品chemicals17. 浓度concentration18. 试管test tube19. 过滤器filter20. 一氧化碳carbon monoxide21.吸附剂adsorbent22.吸附作用adsorption23. 活性炭activated carbon24. 分子molecule 25. 金属metal26. 钙calcium27. 二氧化硫sulfur dioxide四、航空航天1. 国际空间站ISS(InternationalSpace Station)2. 轨道orbit3. 人造卫星artificial satellite4. 载人航天manned space flight5. 航天器spacecraft6. 宇宙cosmos7. 太阳系solar system8. 彗星comet9. 八大行星:水星(Mercury)、金星(Venus)、地球(Earth)、火星(Mars)、木星(Jupiter)、土星(Saturn)、天王星(Uranus)、海王星(Neptune)10. 太空探测器space probe11. 航天飞机space shuttle12. 载人飞船manned spacecraft13. 无人飞船unmanned spacecraft 14. 外太空outer space15. 太空研究spaceexploration /space research16. 驾驶舱cockpit17. 发射装置launcher18. 推进器propeller19. 外星人alien20. 战斗机fighter21. 轰炸机bomber22. 机头nose23. 机翼wing, airfoil24. 飞机跑道airstrip25. 飞机引擎aeroengine26. 飞行技术wingmanship27. 嫦娥二号Chang'e-2 (moon probe)28. 神舟七号Shenzhou VII (spacecraft)29. 载人航天manned space flight30.多级火箭multistage rocket 31. 太空舱capsule32. 返回式卫星recoverable satellite 33. 通信卫星communication satellite34. 遥感卫星remote sensing satellite35. 运载火箭carrier rocket; rocket launcher36. 长征二号F运载火箭Long MarchII F carrier rocket 37. 气象卫星weathersatellite /meteorologicalsatellite38. 轨道舱orbital module39. 返回舱re-entry module40. 推进舱propelling module 41. 指令舱command module 42. 服务舱service module43. 登月舱lunar module44. 发射台launch pad45. 太阳能电池板solar panel46. 太空升降舱space elevator47. 哈勃太空望远镜Hubble SpaceTelescope48. 月球车lunar rover49. 银河系Milky Way50. 太空服space outfits(space suits) 51. 太空食物space food52. 着陆区landing area53. 主着陆场mainlanding field/primary landingsite54. 天线antenna55. 航天员astronaut56. 太空舱capsule57. 多级火箭multistage rocket 58. 第二级secondstage59. 第三级third stage60. 登月舱lunar module61. 着陆架landing pad62. 上升段ascent stage 63. 下降段descent stage64. 舱口hatch65. 扶梯ladder66. 生命维持系统life support system67. 大气输运airborne transport五、医药、生命科学、基因工程1. 干细胞stem cells2. 基因工程genetic engineering3. 克隆clone4. 转基因食品genetically modified foods (GM foods)5. 免疫系统immune system6. 获得性免疫缺陷综合征(艾滋病) acquired immunodeficiency syndrome (AIDS)7. 细菌bacteria8. 可卡因cocaine9. 抗体antibody10. 复制duplication 11. 基因gene12. 基因库gene pool13. 遗传病筛查genetic screening14. 遗传密码genetic code15. 人类基因组计划Human GenomeProject16. 继承的,遗传的inherited17. 白血病leukemia18. 糖尿病diabetes19. 肺结核tuberculosis (TB)20. 甲肝hepatitis A21. 乙肝hepatitis B22. 昏迷(状态)coma23. 歇斯底里hysteria24. 健忘症amnesia25. 失眠insomnia26. 针灸acupuncture27. 妄想症paranoia28. 大麻marijuana29. 吗啡morphine30. 鸦片opium 31. 整形手术plastic surgery32. 维生素,维他命vitamin33. 突变mutation34. 蛋白质protein35. 综合征syndrome36. 荷尔蒙,激素hormone37. 流产abortion38. 急性的acute39. 慢性的chronic40. 草药herbal medicine41. 血管blood vessel42. 牙齿校正orthodontics43. 注射injection44. 紧急救护first aid45. 眩晕的dizzy46. 热量calorie47. 抗生素antibiotics48. 超级病毒supergerm49. 毒素toxin50. 肿瘤tumor51. 外科surgery 52.内科internal medicine53. 神经系统nervous system六、机械1. 精度precision2. 误差error3. 弹性elasticity4. 可靠性reliability5. 齿轮gear6. 发电机generator7. 疲劳fatigue8. 阀门valve9. 老化速率aging rate10. 链chain11. 压碎机crusher12. 圆筒cylinder13. 刀片blade14. 三角尺set square15. 磁悬浮列车Magnetically Levitated Train16. 安全阀safety valve17. 自动化automation18. 缓冲器buffer19. 接头,连接点joint20. 管tube21. 安全帽helmet22. 油箱fuel tank23. 总开关main switch24. 螺丝刀,起子screw driver25. 软水管hose26. 工具包toolkit27. 校准calibrate 28. 金属板,钣金sheet metal七、计算机、通讯、电子1. 卫星定位系统Global PositioningSystem (GPS)2. 电缆cable3. 中央处理器central processing unit (CPU)4. 人工智能artificial intelligence5. 网际空间,虚拟空间cyberspace6. 数字图书馆Digital Library (DL)7. 通信卫星communicationsatellite (comsat)8. 博客blog9. 光纤通信Optical Fiber Communication 10. 蓝牙技术Bluetooth11. 技术要求technical requirements12. 垃圾邮件spam13. 高保真High Fidelity (Hi-Fi)14. 短信服务SMS:Short Message Service 15. 客户身份识别卡SIM卡:SubscriberIdentity Module 16. 数码摄像机DV:Digital Video17. 计算器calculator18. IC卡IC (integrated circuit) card19. 液晶Liquid Crystal20. 液晶显示器,液晶电视liquid crystaldisplay (LCD) 21. 遥感remote sensing22. 信息时代information era/age23. 二进制的binary24. 超文本hypertext25. 浏览器browser26. 鼠标mouse27. 智能系统intelligent system28. 黑客hacker29. 电子助听器electronic hearing aid 30. 网上犯罪cyber crime31. 光标cursor32. 条形码bar code33. 无绳电话cordless telephone34. 加密encryption35. 光纤技术fiber optic technology36. 信息产业IT-industry37. 家用电器electrical appliances 38. 调制解调器modem39. 桌面desktop40. 内存memory41. 显示器monitor42. 路由器router43. 网络摄影webcam44. 使计算机化computerize45. 优盘flash disc八、资源、环境、气候1. 京都议定书Kyoto Protocol2. 太阳电池solar cell3. 酸雨acid rain4. 太阳能solar energy5. 温室效应greenhouse effect6. 水资源Water Resources7. 核能nuclear energy8. 循环经济Recycling Economy9. 气压计barometer10. 臭氧层ozone layer11. 煤气coal gas12. 玷污contamination13. 可替代能源alternative energy 14. 生物多样性bio-diversity15. 动物栖息地habitat16. 除草剂herbicide17. 热岛效应heat island effect18. 不降解的non-degradable19. 绿党green party20. 燃料fuel21. 能源危机energy crisis22. 废气exhaust gas23. 垃圾掩埋地landfill24. 误用,滥用misuse25. 可再生资源renewable energysources26. 天然资源,自然资源natural resources 27. 濒危物种endangered species 28. 寿命life expectancy, life span 29. 可持续发展sustainable development30. 气候变化climate change31. 温室气体greenhouse gases32. 有毒的poisonous, toxic33. 侵蚀erosion34. 处理掉(废品等)dispose35. 污染物pollutant 36. 信风trade wind37. 热带的tropical38. 海啸tsunami39. 毛毛雨drizzle40. 雨夹雪sleet41. 冰雹hail42. 冻雨ice rain43. 气流air current44. 气流侵袭air intrusion45. 气团air mass46. 酸雾acid mist47. 大气化学air chemistry48. 航空气候学aeronautical climatology49. 余震aftershock50. 绿化,造林afforestation九、军事1. 高技术战争high-tech warfare2. 雷达radar3. 航空母舰aircraft carrier4. 雷管blasting cap5. 大规模杀伤性武器weapons of massdestruction6 . 机关枪machine gun7. 步枪,来复枪rifle 8. 冲锋枪tommy gun9. 机枪scatter-gun10. 大炮cannon11. 子弹bullet12. 卡宾枪carabin13. 轰炸bombard14. 自杀式攻击suicidal attack15. 人体炸弹flesh bomb16. 炮弹shell17. 散兵坑foxhole十、其他1. 基础研究basic research2. 研发research and development3. 瓶颈bottleneck4. 专利patent5. 纳米技术nanotechnology6. 应用研究Application Research7. 可行性研究feasibility study8. 知识经济knowledge economy 9. 对照试验control test10. 化妆品cosmetic11. 知识产权intellectualproperty rights、intellectualownership12. 过程分析procedure analysis 13. 土木工程civil engineering14. (技术)诀窍know-how 15. 基础设施infrastructure16.不利效应,不利影响adverse effect17. 杀虫剂pesticide18. 化肥fertilizer19. 食物添加剂food additive20. 农业气象学agrometeorology21. 农用化学品agrochemicals。
碳纳米管复合材料
碳纳米管(Carbon Nanotubes,简称CNTs)是一种由碳原子构成的纳米级管状结构材料,因其独特的物理和化学性质,被广泛应用于复合材料领域。
碳纳米管复合材料是将碳纳米管与其他材料复合而成的新型材料,具有轻质、高强度、高导电性、高导热性等优异特性,被广泛应用于航空航天、汽车制造、电子设备等领域。
首先,碳纳米管复合材料在航空航天领域具有重要应用。
由于碳纳米管本身具有极高的强度和刚度,将其与航空用树脂复合,可以显著提高航空器的强度和耐久性。
同时,碳纳米管复合材料的导电性和导热性也使其成为航空器的理想材料,可以用于制造飞机的航空电子设备外壳和导热结构件。
其次,碳纳米管复合材料在汽车制造领域也有着重要的应用前景。
汽车是碳纳米管复合材料的重要应用领域之一,由于碳纳米管具有轻质高强度的特性,可以显著降低汽车的整体重量,提高汽车的燃油经济性和性能。
同时,碳纳米管复合材料的高导电性也可以应用于汽车的电子设备和充电设备的制造,提高汽车的智能化水平。
此外,碳纳米管复合材料在电子设备领域也有着广泛的应用。
由于碳纳米管具有优异的导电性和导热性,可以用于制造高性能的电子元件,如场效应管、薄膜晶体管等。
同时,碳纳米管复合材料还可以用于制造柔性电子设备,如可穿戴设备、柔性显示屏等,为电子设备的发展带来新的可能性。
总的来说,碳纳米管复合材料以其独特的优异性能,在航空航天、汽车制造、电子设备等领域具有广泛的应用前景。
随着科技的不断发展,相信碳纳米管复合材料将会在更多领域展现出其巨大的潜力,为人类社会的发展进步做出更大的贡献。
The ASENSE Duct series with IP65 Rated Enclosure monitors the carbon dioxide (CO2) levelsin industrial, commercial, school, and office type environments. The concentration of CO2 is astrong indication of the overall indoor air quality. The ASENSE Series is based on a single beamnon-dispersive infrared technology and is a cost-optimized solution for the climate control ofbuildings and other processes. In addition, ABC software eliminates the need for manualcalibration. The ASENSE Series measures the CO2 concentration in the ambient air up to 2,000ppm and converts the data into an analog output. This data can be used in conjunction with aBuilding Automation or Demand Control Ventilation System to create a healthier indoor climate.This series features an analog temperature output (32 to 122°F) and come with combinedoutput options of 0-10 VDC and 0 to 20 mA (4 to 20 mA and 2-10 VDC are field selectable viaan onboard jumper) or 0-5 VDC for “-5” versions. A relay option is available for this series aswell. The UIP5 software and programming cable offer a configuration/test utility and provideaccess to the main features of the ASENSE series.Applications: Commercial Office Buildings, Hospitals & SchoolsNSA-ASENSE-D-LCD-REL NSA-ASENSE-D-RELwave rectified)Power Consumption: <1WWiring Connections: 0.00232 in² (1.5 mm²) screw terminalsOperating Environment: Residential, commercial, and industrial spacesOperating Temperature: 32ºF to 122ºF (0ºC to 50ºC)Operating RH: 0 to 85% RH Non-condensingWarm-Up Time: <5 minutes (@ full specs 15 minutes)Accuracy: CO21: ±30 ppm ±3% of reading | Temperature: ±1.8ºF (1ºC) Repeatability: ±20 ppm ±1% of measured valueAnnual Zero Drift: <± 0.3% of measurement rangeOperating Pressure: +1.6% per 0.145 psi (1 kPa) deviation from normal pressure | (1Atmosphere = 14.7 psi (1.013 KPa))Sensing Method: Single beam Non-dispersive Infrared (NDIR)Sensor Life2: >15 yearsResponse Time (T1/e): <10 seconds @ 30 cc / minimum flow rate, <3 minutes diffusiontimeSensing Range: CO2: 0 to 2000 ppm | Temperature: -4 to 140ºF (-20 to 60ºC) Extended CO2 Ranges: 2000 to 10,000 ppm (factory set or programming cable required) Extended Range Accuracy: +/- 30 ppm and +/- 5% of readingCoverage Area: 7500 sq. ft. maximumSelf-Diagnostics: Complete function check, yellow LED; LCD error indication(display model only)Display (Optional): 4 digits, 7 segments LCD with ppm indicatorCalibration3: Senseair ABC algorithm (Automatic Baseline Correction) Outputs: Out 1 (CO2): 0/2 to 10V, 0/4 to 20 mA, 0 to 2000 ppmOut 2 (Temperature): 0/2 to 10V, 0/4 to 20 mA, 32 to 122ºF (0 to50ºC)Relay (Optional): Out 3: N.O. or N.C. rated 0.5A @ 125 VAC; 1A @ 24 VDCRelay Trip Point4: 1000 ppm (factory set)Relay Deadband/Hysteresis: 100 ppm (factory set)Relay Durability: Mechanical: 5,000,000 operations minimum (at 36,000operations/hr)Electrical: 100,000 operations minimum (under rated load, at1,800 operations/hr)Storage: NSA-ASENSE-D: -40 to 158ºF (-40 to 70ºC)NSA-ASENSE-D-LCD: -4 to 122ºF (-20 to 50ºC) 0 to 85% RHNon-condensingEnclosure: Duct Box: PC & ABS blend, Flammability Rating UL94V-0Cover: Makrolon® 6555 plastic, Flammability Rating UL94V-0Pipe: PC & ABS blend, Flammability Rating UL94V-0Product Dimensions: (H) 5.95” (151.9 mm) x (W) 3.33” (84.6 mm) x (D) 1.85” (47 mm) Product Weight: 0.812 lbs (0.368 kg)Agency Approvals: EMC Directive 2014/30/EC, RoHS Directive 2011/65/EU & RoHS3 Directive 2015/863/EU1Accuracy is defined after minimum three (3) ABC periods (1 period = 8 days) of continuous operations2In normal Indoor Air Quality (IAQ) applications | Corrosive environments are excluded3Building CO2 levels must drop to 400 ppm some time during the week for ABC to work properly | If the building is occupied 24 hrs/day, ABC must be turned off4Changes can be made using TTL-232R-3V3 cable and UIP5 softwareDimensional DrawingInstallation1.2.3.4.5.6.Dismounting the sensorPush the front part of the lid upwards while keeping the wallplate steady Fold the front part with the lid forwards and loose it from the hooks (#1)Mounting the sensorThe wall plate is screwed onto the wallThe screw head diameter should be max 7,5 mm The screw head height should be max 2,5 mm (A) Put the top tabs of the front part into the top holes of the wall plate.(B) Press the lower edge of the case onto the wall plate to latchThe top part is pushed under the locking hooks ofthe wall plate and secured with a screw. Terminals and jumpers on aSENSE RL.The darker positions are default settings.Terminals and jumpers are located under the top part.CAUTION If the PCB must be removed, it must be handed carefully and protected from electrostatic discharge! Removing the PCB is not normally required.Electrical connectionsThe power supply has to be connected to ⨤ and ┴. ┴ is considered as system ground. If the analogue output is connected to a controller, the same ground reference has to be used for the aSENSE RL unit and for the control system. Unless different transformers are used, special precautions must be taken.IMPORTANT The same ground reference has to be used for the aSENSE RL unit and for the control system. If possible1The ground terminal is used as negative power supply DC input or AC phase ground (halfwave rectifier). A single transformer may be used for the entire system.2aSENSE RL can deliver a voltage or a current loop for Out(1) / Out(2). To change between voltage and current output mode the hardware jumpers are used. There is one jumper for Out(1) and one for Out(2), so that one output can be a voltage output and the other a current output. Both, voltage output and current output can have start points 0 % (0-10 VDC or 0-20mA) or 20% (2-10 VDC or 4-20mA). The same start point is used for both outputs. See the function manual.3Please use voltage outputs for temperature measurements. The accuracy of temperature measurements is valid only for units configured in voltage outputs mode.Dimensions of sensor in mm and (inches)Mounting the sensor to the wallUse screws with head diameter less than 7,5 mm (0,295 inches) and head height less than 2,5 mm (0,1 inches)NSA-TTL-232R-3V3 programming cable is required.1. Download the UIP5 software from the SenseAir website. /products/software/uip-5/2. Plug the programming cable into a USB port, and go into Device Manager on the computer to determine which port isbeing used.3. Open the UIP5 software.4. Power the sensor on and plug the programming cable into the sensor. The programming cable must have the blackwire with the arrow connected towards the top of the connector on PCB as shown in Figure 1.Figure 15. Click the Meter tab at the top of page. In the Connection Configuration window:a. Select Com Port.b. Set Baud rate to 9600.c. Set Parity to NONE.d. Click Save.Figure 26. Go to Meter, and click Connect.7. Select Any Address and all interface types.8. Click Connect. The unit takes approximately 30 seconds to connect.Figure 39. You can now adjust your settings: ABC can be turned off, change ppm, change output scale, etc.10. After the settings are changed, power cycled the sensor.Figure 4Click “SET” after adjustment is made.Calibration:∙-100% nitrogen for zero calibration - /disposable-calibration-gas/nitrogen-n2/∙-0.25lpm regulator - /disposable-calibration-gas/series-400-17l/34l-preset-flow-regulator-for-disposables/∙-1K PPM Span Gas for Bump Test - https:///disposable-calibration-gas/carbon-dioxide-co2/1. Click the CO2 tab at the bottom of the page.2. Ensure the target box under Calibration is set to “0”.3. Apply the Nitrogen gas to above the CO2 sensor filter. On the Asense, Carrier recommens removing the PCB fromthe enclosure for best results.Figure 54. Wait until the CO2 reading on the UIP5 stabilizes at 0 ppm and press Calibrate on the UIP5 screen.5. After the calibration process, check CO2 readings using a known ppm test gas for verification.。
高效杂元素碳-纳米硅复合锂离子电池负极材料下载提示:该文档是本店铺精心编制而成的,希望大家下载后,能够帮助大家解决实际问题。
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CHEMICAL INDUSTRY AND ENGINEERING PROGRESS 2017年第36卷第8期·2924·化 工 进展超临界二氧化碳中合成环碳酸酯的催化剂研究进展范芳君,张治国,邢华斌,杨启炜,鲍宗必,杨亦文,任其龙(浙江大学化学工程与生物工程学院,生物质化工教育部重点实验室,浙江 杭州 310027)摘要:超临界二氧化碳(scCO 2)是一种环境友好型溶剂,它作为传统有机溶剂的替代品已被广泛应用于绿色化学过程的开发。
其中,环氧化合物在超临界二氧化碳中制备环碳酸酯是实现二氧化碳高附加值转化的有效途径之一。
本文回顾了近年来在超临界二氧化碳中合成环碳酸酯的研究进展,着重介绍了不同种类的催化剂,包括金属配合物、季盐、二元催化体系、离子液体、金属氧化物、有机小分子及其他类型催化剂在该反应体系中的应用,突出了超临界二氧化碳既作为溶剂,又作为反应物的双重优势。
从经济和环境角度考虑,离子液体或季盐等有机催化剂具有更好的工业化应用前景。
同时,指出了高效和绿色催化体系设计和创制是该研究领域的关键。
关键词:超临界二氧化碳;环碳酸酯;环氧化物;催化中图分类号:TQ072 文献标志码:A 文章编号:1000–6613(2017)08–2924–10 DOI :10.16085/j.issn.1000-6613.2016-2446Progress in synthesis of cyclic carbonates under supercritical carbondioxideF AN Fangjun ,ZHANG Zhiguo ,XING Huabing ,YANG Qiwei ,BAO Zongbi ,YANG Yiwen ,REN Qilong(Key Laboratory of Biomass Chemical Engineering of Ministry of Education ,College of Chemical and BiologicalEngineering ,Zhejiang University ,Hangzhou 310027,Zhejiang ,China )Abstract :Supercritical carbon dioxide (scCO 2)has been widely used as an environmentally friendly solvent to replace the conventional organic solvent in green chemical processes. Among those applications reported ,the synthesis of cyclic carbonates from epoxides in supercritical CO 2 has received a great interest. This review covered the recent progress in the synthesis of cyclic carbonates under supercritical carbon dioxide ,with an emphasis on the state of the art of different kinds of catalysts employed in this reaction ,including metal complex ,quaternary onium salts ,binary catalytic systems ,ionic liquids ,metal oxide ,organocatalysts ,et al. Furthermore ,the advantages of supercritical carbon dioxide both as solvent and as reactant for this transformation were highlighted. From the economic and environmental point of view ,organic catalysts ,such as ionic liquids and quaternary onium salts ,show promising potential application in the future development of chemical industry. It was also pointed out that the design and preparation of efficient and green catalysts are critical to this research field. Key words :supercritical carbon dioxide ;epoxides ;cyclic carbonates ;catalysisCO 2性质稳定,无毒,不燃,价廉易得,是主要的温室气体之一,同时也是目前地球上储量最为丰富的C 1资源[1-2]。
小学上册英语第四单元暑期作业(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.__________ are important for maintaining balance in nature.2.I _____ (love) chocolate.3.The sheep gives us _________ (羊毛).4.The park has a _____ (playground/garden).5.What do you call a group of stars?A. GalaxyB. UniverseC. ConstellationD. Nebula答案:C6.The starfish can regenerate its _________ (臂).7.My aunt is a ______. She helps manage events.8.My dad takes care of our _______ (我爸爸照顾我们的_______).9. A __________ is formed through the interaction of biotic and abiotic factors.10.What is the capital of Kenya?A. NairobiB. MombasaC. KisumuD. Nakuru11.The ancient Greeks used _______ to measure time. (日晷)12.My favorite season is ________.13.What is 20 - 10?A. 5B. 10C. 15D. 20答案:B14.What is the capital city of Zimbabwe?A. HarareB. BulawayoC. GweruD. Mutare15.What is the name of the famous landmark in New York City?A. Statue of LibertyB. Eiffel TowerC. Big BenD. Colosseum16.Which of these is a cold beverage?A. TeaB. CocoaC. LemonadeD. Coffee答案:C17.What is the capital city of Hungary?A. BudapestB. PragueC. ViennaD. Bratislava18.The ________ (人工栽培) supports agriculture.19.What is the opposite of "fast"?A. QuickB. SlowC. RapidD. Speedy20.I like to help my mom ________ (做家务).21.The train goes _____ (fast/slow) on the tracks.22.Astrobiology studies the possibility of ______ in the universe.23.How many wheels does a bicycle have?A. OneB. TwoC. ThreeD. Four答案:B24.The __________ is a large area of forest located in Canada. (温带雨林)25.We will go camping _____ (this/next) weekend.26.Density is defined as mass per _____.27.The koala sleeps in a _________. (树上)28.What do you call the area around a city?A. SuburbB. CountrysideC. UrbanD. Rural29.Which animal has a pouch?A. DogB. CatC. KangarooD. Lion答案:C30.What do we celebrate on New Year's Eve?A. ChristmasB. BirthdayC. New YearD. Halloween答案:C31.We make ________ (decisions) as a team.32.The chemical symbol for selenium is ____.33.What do you wear on your feet?A. HatB. ShoesC. GlovesD. Scarf答案:B34.What do we call a place where we can see the stars?A. ObservatoryB. PlanetariumC. MuseumD. Gallery35.What do we call the area of land that is covered by trees?A. ForestB. WoodlandC. JungleD. All of the above答案:D All of the above36.What is the national language of China?A. JapaneseB. MandarinC. KoreanD. Thai37.What do we call a person who studies history?A. HistorianB. ArchaeologistC. ScientistD. Geographer答案:A38.How do you say "bird" in Spanish?A. PájaroB. OiseauC. VogelD. Uccello39.The __________ (历史的探索) unveils truths.40.What is the shape of a basketball?A. SquareB. RectangleC. OvalD. Circle答案:D41. A supernova is a powerful explosion of a dying ______.42.My grandma is a great __________ (故事讲述者).43.小猫) stretches in the sun. The ___44.My favorite animal is a _______ because it is _______ (我最喜欢的动物是_______因为它_______).45.__________ (化学反应速率常数) quantifies the speed of a reaction under specific conditions.46.I planted a _____ (树) in my garden.47.What do you call a story that is not true?A. FactB. FictionC. HistoryD. News答案:B48.Which shape has three sides?A. SquareB. TriangleC. CircleD. Rectangle49.The chemical formula for potassium chloride is ______.50.What is the largest organ in the human body?A. HeartB. BrainC. SkinD. Liver答案:C Skin51.What do you call a scientist who studies rocks?A. GeologistB. BiologistC. ChemistD. Physicist52.The ancient Romans built ________ to honor their gods.53.My aunt loves to volunteer at the ____ (shelter).54.The chemical formula for carbon monoxide is __________.55. A __________ is a mixture that can be separated by evaporation.56.My favorite game is ________.57. A _____ (自然之美) can be seen in every garden.58.What do we call a picture made by painting or drawing?A. SculptureB. ArtworkC. PhotographD. Collage59.What is the name of the popular video game where you build and explore worlds?A. MinecraftB. TerrariaC. RobloxD. Stardew Valley答案:A60.How many hours are in a day?A. 24B. 12C. 36D. 4861.Metals are usually ______ at room temperature.62.My cousin is very __________ (容易相处).63. A _______ is a type of tree that produces acorns.64.What do we call a baby sheep?A. CalfB. KidC. LambD. Foal答案:C65.I enjoy playing with my ________ (拼搭玩具) to create new designs.66.I like to play with my toy ________ (玩具名称) at the library.67.What is the name of the fairy tale character who eats a poisoned apple?A. CinderellaB. Snow WhiteC. RapunzelD. Belle68.The _____ (小鸭) quacks happily in the water.69.Water freezes at ______ degrees Celsius.70.Which food is made from eggs and often eaten for breakfast?A. ToastB. PancakeC. OmeletD. Cereal答案:C71.My favorite dish is ______ (意大利菜).72.The __________ is a famous desert in the United States.73.Which number comes after 7?A. 6B. 8C. 9D. 1074.How many states are in the USA?A. 48B. 50C. 52D. 54答案:B75.ts have developed specific traits to cope with ______ stress. (某些植物发展出特定特征以应对环境压力。
超临界co2 mxene超临界CO2 MXene:未来材料的希望在当今科技发展的浪潮下,超临界CO2 MXene作为一种新型材料备受瞩目。
它的独特性能和广泛应用前景使其成为了科学界的宠儿。
本文将从不同角度探讨超临界CO2 MXene的特点和应用,让读者对这一材料有一个全面的了解。
让我们来了解超临界CO2 MXene的基本概念。
超临界CO2 MXene 是一种二维材料,其结构特点是由碳、氧和金属元素构成的多孔结构。
这种多孔结构使其具有较大的比表面积和优异的导电性能,可以在电子器件、催化剂和储能材料等领域发挥重要作用。
在电子器件领域,超临界CO2 MXene的高导电性和可调控的能带结构使其成为了理想的材料之一。
它可以被用来制作高性能的电子器件,如超级电容器和柔性电子元件。
超临界CO2 MXene的导电性和机械柔性使得它可以适应不同形状和尺寸的设备,并且具有较高的可靠性和稳定性。
超临界CO2 MXene在催化剂领域也展现出了巨大的潜力。
由于其多孔结构和丰富的活性位点,它能够提供更多的催化活性中心,从而提高催化反应的效率。
这使得超临界CO2 MXene成为了制备高效催化剂的理想选择,可以应用于环境保护和能源转换等领域。
超临界CO2 MXene在储能材料方面也具有重要的意义。
其多孔结构和高比表面积使其能够有效地储存和释放能量。
超临界CO2 MXene 可以用作电池的电极材料,提高电池的能量密度和循环寿命。
同时,它还可以用于超级电容器的制备,实现高效的电荷和放电过程。
超临界CO2 MXene作为一种新兴材料,在电子器件、催化剂和储能材料等领域具有广泛的应用前景。
它的独特性能和多功能性使其成为了科学研究和工程应用的热点。
我们对超临界CO2 MXene的研究和应用还有很多待发掘的领域,相信随着科技的不断进步,超临界CO2 MXene必将为人类带来更多的惊喜和变革。
让我们拭目以待,期待着超临界CO2 MXene为未来科技发展带来的巨大贡献!。
MSDS活性炭SAFETY DATA SHEET (GHS, Appendix 4)Date : 14/11/2017 Page 1/10 Version : N°3 (23/05/2017)Revision : N°2 (11/05/2015) Jacobi Carbons Industry (Tianjin) Co. LtSteam Activated Carbon, Granular, Coal base - Activated CarbonSAFETY DATA SHEETSECTION 1 : IDENTIFICATION OF THE SUBSTANCE/MIXTURE AND OF THE COMPANY/UNDERTAKING1.1. Product identifierProduct name : Steam Activated Carbon, Granular, Coal base Product code : Activated Carbon.1.2. Relevant identified uses of the substance or mixture and uses advised againstUse as an adsorbent in industrial, professional and consumer setting.1.3. Details of the supplier of the safety data sheetRegistered company name : Jacobi Carbons Industry (Tianjin) Co. Ltd. .Address : No. 46, 5th Coastal Way - TJPFTZ, Tanggu, Tianjin, 300456...People's Republic of China.Telephone : +86 22 25764846 . Fax : +86 22 25763228 .msds@/doc/7b503059.html,/doc/7b503059.html,1.4. Emergency telephone number : +86 22 25764846.Association/Organisation : Jacobi Carbons Industry (Tianjin) Co. Ltd. .SECTION 2 : HAZARDS IDENTIFICATION2.1. Classification of the substance or mixtureGHS compliant.This substance does not present a physical hazard. Refer to the recommendations regarding the other products present on the site.This substance does not present a health hazard with the exception of possible occupational exposure thresholds (see paragraphs 3 and8).This substance does not present an environmental hazard. No known or foreseeable environmental damage under standard conditions of use.2.2. Label elementsGHS compliant.No labelling requirements for this substance.2.3. Other hazardsIn the event of dust formed by mechanical action (sanding, sawing, etc..), this dust may cause irritation by inhalation and contact with eyes.May cause CO and CO2 emanations in the event of a fire.According to the ECHA Guidance on chemical safety assessment, Chapter R11, section R11.1.2.1: "The PBT and vPvB criteria of Annex XIII to the Regulation do not apply to inorganic substances". As Activated Carbon - HDS type is to be considered as an inorganic substance, the PBT assessment is not applicable.Wet Activated Carbon depletes oxygen from air and, therefore, dangerously low levels of oxygen may be encountered. Whenever workers enter a vessel containing activated carbon, the oxygen content should be determined and work procedures for potentially low oxygen areas should be followed.-M a d e u n d e r l i c e n c e o f E u r o p e a n L a b e l S y s t e m ?M S D S so f t w a r e f r o m I n f o D y n e -h t t p : / / w w w . i n f o d y n e . f r -SAFETY DATA SHEET (GHS, Appendix 4)Date : 14/11/2017 Page 2/10 Version : N°3 (23/05/2017)Revision : N°2 (11/05/2015) Jacobi Carbons Industry (Tianjin) Co. LtSteam Activated Carbon, Granular, Coal base - Activated CarbonSECTION 3 : COMPOSITION/INFORMATION ON INGREDIENTS3.1. SubstancesComposition :Identification GHS Note%CAS: 7440-44-0EC: 931-328-0REACH: 01-2119488894-16-0013ACTIVATED CARBON - HIGH DENSITYSKELETON (AC-HDS)[1]100%Information on ingredients :A porous, amorphous, high surface area adsorbent material composed largely of elemental carbon.[1] Substance for which maximum workplace exposure limits are available.SECTION 4 : FIRST AID MEASURESAs a general rule, in case of doubt or if symptoms persist, always call a doctor.NEVER induce swallowing by an unconscious person.4.1. Description of first aid measuresIn the event of exposure by inhalation :If breathing is irregular or has stopped, effect mouth-to-mouth resuscitation and call a doctor.Fresh air, rest.Obtain medical attention if cough or respiratory symptoms develop.In the event of splashes or contact with eyes :Wash thoroughly with fresh, clean water for 15 minutes holding the eyelids open.If there is any redness, pain or visual impairment, consult an ophthalmologist.In the event of splashes or contact with skin :Watch out for any remaining product between skin and clothing, watches, shoes, etc.Rince with water and soap.Remove contaminated clothes.Obtain medical attention if irritation becomes apparent.In the event of swallowing :Do not give the patient anything orally.In the event of swallowing, if the quantity is small (no more than one mouthful), rinse the mouth with water and consult a doctor. Seek medical attention immediately, showing the label.Give at least 1/2 L of water to drink.Obtain mediacl attention if gastrintestinal symptoms develop.Do not induce vomiting.4.2. Most important symptoms and effects, both acute and delayedWhen large amounts are ingested orally, congestion may occur.4.3. Indication of any immediate medical attention and special treatment neededSpecific and immediate treatment :N/A -M a d e u n d e r l i c e n c e o f E u r o p e a n L a b e l S y s t e m ?M S D S s o f t w a r e f r o m I n f o D y n e -h t t p : / / w w w . i n f o d y n e . f r -SAFETY DATA SHEET (GHS, Appendix 4)Date : 14/11/2017 Page 3/10 Version : N°3 (23/05/2017)Revision : N°2 (11/05/2015) Jacobi Carbons Industry (Tianjin) Co. LtSteam Activated Carbon, Granular, Coal base - Activated CarbonInformation for the doctor :Medications efficiency can be reduced by the adsorbing power of the activated carbon.SECTION 5 : FIREFIGHTING MEASURES5.1. Extinguishing mediaSuitable methods of extinctionIn the event of a fire, use :- sprayed water or water mist- carbon dioxide (CO2)- foam- powderUnsuitable methods of extinctionIn the event of a fire, do not use :- water jetin the closed areas, in order to avoid the water contamination.5.2. Special hazards arising from the substance or mixtureA fire will often produce a thick black smoke. Exposure to decomposition products may be hazardous to health.Do not breathe in smoke.In the event of a fire, the following may be formed :- carbon monoxide (CO)- carbon dioxide (CO2)- other decomposition products for the saturated activated carbon.After a fire, smoldering hotspots within the activated carbon may be present for a long time.Activated Carbon which has been allowed to smolder for a long time in a confined space may accumulate carbon monoxide above its lower explosion limit.5.3. Advice for firefightersDue to the toxicity of the gas emitted on thermal decomposition of the products, fire-fighting personnel are to be equipped with autonomous insulating breathing apparatus.SECTION 6 : ACCIDENTAL RELEASE MEASURES6.1. Personal precautions, protective equipment and emergency proceduresConsult the safety measures listed under headings 7 and 8.For first aid workerFirst aid workers will be equipped with suitable personal protective equipment (See section 8).6.2. Environmental precautionsPrevent any material from entering drains or waterways.6.3. Methods and material for containment and cleaning upRetrieve the product by mechanical means (sweeping/vacuuming).6.4. Reference to other sectionsSee also sections 2 & 8-M a d e u n d e r l i c e n c e o f E u r o p e a n L a b e l S y s t e m ?M S D S s o f t w a r e f r o m I n f o D y n e -h t t p : / / w w w . i n f o d y n e . f r -SAFETY DATA SHEET (GHS, Appendix 4)Date : 14/11/2017 Page 4/10 Version : N°3 (23/05/2017)Revision : N°2 (11/05/2015)Jacobi Carbons Industry (Tianjin) Co. LtSteam Activated Carbon, Granular, Coal base - Activated CarbonSECTION 7 : HANDLING AND STORAGERequirements relating to storage premises apply to all facilities where the substance is handled.7.1. Precautions for safe handlingAlways wash hands after handling.Prevent dust generation. Apply good working practices and engineering procedures during discharge.See the exposure controls and personal protection measures in the section 8.Fire prevention :Prevent access by unauthorised personnel.Prevent dust generation.Keep away from heat sources.Immediately retrieve the product in case of spillingRecommended equipment and procedures :For personal protection, see section 8.Observe precautions stated on label and also industrial safety regulations.Ensure containment and adequate ventilation.Whenever workers enter a vessel containing activated carbon, the oxygen content should be determined and work procedures for potentially low oxygen areas should be followed.Prohibited equipment and procedures :No smoking, eating or drinking in areas where the substance is used.7.2. Conditions for safe storage, including any incompatibilitiesKeep away from any chemical (solvents and strong oxidisers).Keep away from heat sources.Store in a well-ventilated area.Keep the container away from dampnessStorageStore and keep away from any chemical (solvents and strong oxidisers).Storage of wet activated carbon in a closed area can deplete oxygen from air.PackagingAlways keep in packaging made of an identical material to the original.Store in the closed, original packaging.7.3. Specific end use(s)No data available.SECTION 8 : EXPOSURE CONTROLS/PERSONAL PROTECTION8.1. Control parametersOccupational exposure limits :Non otherwise classified dusts : 10 mg/m3- UK / WEL (Workplace exposure limits, EH40/2005, 2007) : CAS TWA :STEL :Ceiling :Definition :Criteria : 7440-44-0 4 mg/m3Biological limits :/Derived no effect level (DNEL) or derived minimum effect level (DMEL): ACTIVATED CARBON - HIGH DENSITY SKELETON (AC-HDS) (CAS: 7440-44-0)-M a d e u n d e r l i c e n c e o f E u r o p e a n L a b e l S y s t e m ?M S D S s o f t w a r e f r o m I n f o D y n e -h t t p : / / w w w . i n f o d y n e . f r -SAFETY DATA SHEET (GHS, Appendix 4)Date : 14/11/2017Page 5/10 Version : N°3 (23/05/2017)Revision : N°2 (11/05/2015) Jacobi Carbons Industry (Tianjin) Co. LtSteam Activated Carbon, Granular, Coal base - Activated CarbonFinal use: Workers.Exposure method: Inhalation.Potential health effects: Short term local effects.DNEL : 3 mg of substance/m3Exposure method: Inhalation.Potential health effects: Long term systemic effects.DNEL : 3 mg of substance/m3Final use: Consumers.Exposure method: Inhalation.Potential health effects: Short term local effects.DNEL : 0.5 mg of substance/m3Exposure method: Inhalation.Potential health effects: Long term systemic effects.DNEL : 0.5 mg of substance/m38.2. Exposure controlsAppropriate engineering controlsLocal exhaust ventilation is recommended.For the use of Granular Activated Carbon, no risk management measures are mandatory, but only recommended.Personal protection measures, such as personal protective equipmentUse personal protective equipment that is clean and has been properly maintained.Store personal protective equipment in a clean place, away from the work area.Never eat, drink or smoke during use. Remove and washcontaminated clothing before re-using. Ensure that there is adequate ventilation, especially in confined areas.- Eye / face protectionAvoid contact with eyes.Before handling powders or dust emission, wear mask goggles in accordance with standard EN166.- Hand protectionWear suitable protective gloves in the event of prolonged or repeated skin contact.- Body protectionWork clothing worn by personnel shall be laundered regularly.After contact with the product, all parts of the body that have been soiled must be washed.- Respiratory protectionAvoid breathing dust.Type of FFP mask :Wear a disposable half-mask dust filter in accordance with standard EN149.Category :- FFP2Particle filter according to standard EN143 :- P (White)Exposure controls linked to environmental protectionLocal exhaust ventilation to remove material at source.Contained storage.Regulated waste disposal.-M a d e u n d e r l i c e n c e o f E u r o p e a n L a b e l S y s t e m ?M S D S s o f t w a r e f r o m I n f o D y n e -h t t p : / / w w w . i n f o d y n e . f r -SAFETY DATA SHEET (GHS, Appendix 4)Date : 14/11/2017Page 6/10 Version : N°3 (23/05/2017)Revision : N°2 (11/05/2015) Jacobi Carbons Industry (Tianjin) Co. LtSteam Activated Carbon, Granular, Coal base - Activated CarbonSECTION 9 : PHYSICAL AND CHEMICAL PROPERTIES9.1. Information on basic physical and chemical propertiesGeneral information :Physical state :Solid in granules.Color:BlackOdour:NoneImportant health, safety and environmental informationpH (aqueous solution) :7-11pH :Not relevant.Boiling point/boiling range :Not relevant.Flash point interval :Not relevant.Explosive properties, lower explosivity limit (%) :NCExplosive properties, upper explosivity limit (%) :NCVapour pressure (50°C) :Not relevant.Density :200-700 kg/m3Method for determining the density :ASTM D2854Water solubility :Insoluble. 0Method for determining the water solubility :OCDE Guideline 105 (Water solubility).Fat solubility :0Partition coefficient: n-octanol/water :NAMelting point/melting range :Not relevant.Self-ignition temperature :Not relevant.Decomposition point/decomposition range :Not relevant.9.2. Other informationPhysical and chemical properties of the saturated activated carbon may be different from the virgin material.SECTION 10 : STABILITY AND REACTIVITY10.1. ReactivityThis product shows no reactivity under the specified conditions of storage, shipment and use.10.2. Chemical stabilityThis substance is stable under the recommended handling and storage conditions in section 7.10.3. Possibility of hazardous reactionsIn contact with solvents and strong oxidisers.10.4. Conditions to avoidAvoid :- formation of dusts- heating- heat- humidityDusts can form an explosive mixture with air.10.5. Incompatible materialsKeep away from :- strong oxidising agents- combustible material -M a d e u n d e r l i c e n c e o f E u r o p e a n L a b e l S y s t e m ?M S D S s o f t w a r e f r o m I n f o D y n e -h t t p : / / w w w . i n f o d y n e . f r -SAFETY DATA SHEET (GHS, Appendix 4)Date : 14/11/2017 Page 7/10 Version : N°3 (23/05/2017)Revision : N°2 (11/05/2015) Jacobi Carbons Industry (Tianjin) Co. LtSteam Activated Carbon, Granular, Coal base - Activated Carbon- strong acids- solvents10.6. Hazardous decomposition productsThe thermal decomposition may release/form :- carbon monoxide (CO)- carbon dioxide (CO2)SECTION 11 : TOXICOLOGICAL INFORMATION11.1. Information on toxicological effectsIn the event of dust formed by mechanical action (sanding, sawing, etc..), this dust may cause irritation by inhalation and contact with eyes.11.1.1. SubstancesBased on the physical and chemical properties of activated carbons, the absence of effects on toxicological studies and the therapeutic use of activated carbons as adsorbing agents for the treatment of acute poisoning and acute diarrhoea, it can be expected that Activated Carbon is not absorbed via the oral, dermal and inhalation routes.Acute toxicity :ACTIVATED CARBON - HIGH DENSITY SKELETON (AC-HDS) (CAS: 7440-44-0)Oral route :LD50 > 2000 mg/kgSpecies : RatOECD Guideline 423 (Acute Oral toxicityAcute T oxic Class Method) Inhalation route (Dusts/mist) :LC50 > 64.4 mg/l Species : RatOECD Guideline 403 (Acute Inhalation Toxicity)Skin corrosion/skin irritation :ACTIVATED CARBON - HIGH DENSITY SKELETON (AC-HDS) (CAS: 7440-44-0)Corrosivity :No observed effect.Species : RabbitOECD Guideline 404 (Acute Dermal Irritation / Corrosion)Serious damage to eyes/eye irritation :ACTIVATED CARBON - HIGH DENSITY SKELETON (AC-HDS) (CAS: 7440-44-0)Corneal haze :Average score = 0.00Species : RabbitDuration of exposure : 72 hOECD Guideline 405 (Acute Eye Irritation / Corrosion) Iritis :Average score = 0.00Species : RabbitDuration of exposure : 72 hOECD Guideline 405 (Acute Eye Irritation / Corrosion) Conjunctival redness :Average score = 0.67Species : RabbitDuration of exposure : 72 hOECD Guideline 405 (Acute Eye Irritation / Corrosion) Conjunctival oedema :Average score = 0.33Species : RabbitDuration of exposure : 72 h -M a d e u n d e r l i c e n c e o f E u r o p e a n L a b e l S y s t e m ?M S D S s o f t w a r e f r o m I n f o D y n e -h t t p : / / w w w . i n f o d y n e . f r -SAFETY DATA SHEET (GHS, Appendix 4)Date : 14/11/2017 Page 8/10 Version : N°3 (23/05/2017)Revision : N°2 (11/05/2015) Jacobi Carbons Industry (Tianjin) Co. LtSteam Activated Carbon, Granular, Coal base - Activated CarbonOECD Guideline 405 (Acute Eye Irritation / Corrosion)Respiratory or skin sensitisation :- Skin Not sensitising.- Inhalation No information availableACTIVATED CARBON - HIGH DENSITY SKELETON (AC-HDS) (CAS: 7440-44-0)Local lymph node stimulation test :Non-Sensitiser.Species : MouseOECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)Germ cell mutagenicity :All the key studies indicate that the substance does not show any genotoxic potential. Therefore, it can be concluded that the substance is not mutagenic and does not need to be classified for mutagenicity according to the criteria outlined in Annex I of 1272/2008/EC (CLP / EU GHS) and Annex VI of 67/548/EEC (DSD/DPD).ACTIVATED CARBON - HIGH DENSITY SKELETON (AC-HDS) (CAS: 7440-44-0)Mutagenesis (in vitro) :Negative.Species : BacteriaOECD Guideline 471 (Bacterial Reverse Mutation Assay)Ames test (in vitro) :Negative.With or without metabolic activation.Species : S. typhimurium TA1535Carcinogenicity :No data availableReproductive toxicant :No data availableSpecific target organ systemic toxicity - single exposure :ACTIVATED CARBON - HIGH DENSITY SKELETON (AC-HDS) (CAS: 7440-44-0)Oral route : C > 2000 mg/kg bodyweightSpecies : RatSECTION 12 : ECOLOGICAL INFORMATION12.1. Toxicity12.1.1. SubstancesAs Activated Carbon is insoluble in water, no toxicity is expected.12.2. Persistence and degradabilityActivated Carbon - HDS type is a refractory materail and not amenable to break down by any natural chemical or enzymatic processes.AC - HDS cannot be rendered into a soluble form capable of being absorbed.Therefore it cannot find its way to any cell site where it could be conceivably be biodegraded.12.3. Bioaccumulative potentialThe substance has a very low potential to bioaccumulate in aquatic species (e.g. fish), i.e. a BCF < 10.The substance has no log Kow, the substance size will impede passing membranes (particles with size > 0.5μm) and is not soluble in water. The bioaccumulation study is thus infeasible.12.4. Mobility in soilNo data available, as the substance is insoluble.-M a d e u n d e r l i c e n c e o f E u r o p e a n L a b e l S y s t e m ?M S D S s o f t w a r e f r o m I n f o D y n e -h t t p : / / w w w . i n f o d y n e . f r -SAFETY DATA SHEET (GHS, Appendix 4)Date : 14/11/2017 Page 9/10 Version : N°3 (23/05/2017)Revision : N°2 (11/05/2015) Jacobi Carbons Industry (Tianjin) Co. LtSteam Activated Carbon, Granular, Coal base - Activated Carbon12.5. Results of PBT and vPvB assessmentAccording to the ECHA Guidance on chemical safety assessment, Chapter R11, section R11.1.2.1: "The PBT and vPvB criteria of Annex XIII to the Regulation do not apply to inorganic substances". As Activated Carbon - HDS type is to be considered as an inorganic substance, the PBT assessment is not applicable.12.6. Other adverse effectsNo data available.SECTION 13 : DISPOSAL CONSIDERATIONSThe appropriate waste management of the substance and/or its container must be determined in accordance with local regulations.13.1. Waste treatment methodsDo not pour into drains or waterways.Waste :Waste management is carried out without endangering human health, without harming the environment and, in particular without risk to water, air, soil, plants or animals.Recycle or dispose of waste in compliance with current legislation, preferably via a certified collector or company.Do not contaminate the ground or water with waste, do not dispose of waste into the environment.Soiled packaging :Empty container completely. Keep label(s) on container.Give to a certified disposal contractor.SECTION 14 : TRANSPORT INFORMATIONTransport product in compliance with provisions of the ADR for road, RID for rail, IMDG for sea and ICAO/IATA for air transport (ADR 2015 - IMDG 2014 - ICAO/IATA 2016).14.1. UN number136214.2. UN proper shipping nameUN1362=CARBON, ACTIVATED14.3. Transport hazard class(es)- Classification :4.2- ExemptionADR/RID: special provision 646IMDG: special provision 925> Steam activated carbonIATA: special provision A3> Does not meet the defined criteria, after having been submitted to the 4.2 test (UN Manual of Tests and Criteria (§ 33.3.1.3.3)) US-DOT, 49CFR173.124: Does not meet the defined criteria, after having been submitted to the 4.2 test (UN Manual of Tests and Criteria (§ 33.3.1.3.3))14.4. Packing groupIII14.5. Environmental hazards-14.6. Special precautions for userADR/RID Class Code Pack /doc/7b503059.html,bel Ident.LQ Provis.EQ Cat.Tunnel4.2S2III 4.2400646E14EIMDG Class2°Label Pack gr.LQ EMS Provis.EQ4.2-III0F-A,S-J223 925E1IATA Class2°Label Pack gr.Passager Passager Cargo Cargo note EQ -M a d e u n d e r l i c e n c e o f E u r o p e a n L a b e l S y s t e m ?M S D S s o f t w a r e f r o m I n f o D y n e -h t t p :/ / w w w . i n f o d y n e . f r -SAFETY DATA SHEET (GHS, Appendix 4)Date : 14/11/2017 Page 10/10 Version : N°3 (23/05/2017)Revision : N°2 (11/05/2015) Jacobi Carbons Industry (Tianjin) Co. LtSteam Activated Carbon, Granular, Coal base - Activated Carbon4.2-III4720.5 kg4720.5 kg A3E14.2-III Forbidden Forbidden--A3E1For limited quantities, see part 2.7 of the OACI/IATA and chapter 3.4 of the ADR and IMDG.For excepted quantities, see part 2.6 of the OACI/IATA and chapter 3.5 of the ADR and IMDG.14.7. Transport in bulk according to Annex II of Marpol and the IBC CodeNo data available.SECTION 15 : REGULATORY INFORMATION15.1. Safety, health and environmental regulations/legislation specific for the substance or mixture The following regulations have been used:- Globally Harmonized System of Classification and Labelling of Chemicals (GHS), review no. 5 (2013)- Container information:No data available.- Particular provisions :No data available.- Standardised American system for the identification of hazards presented by the product in view ofemergency procedures (NFPA 704) :NFPA 704, Labelling: Health=0 Inflammability=1 Instability/Reactivity=1 Specific Risk=none10115.2. Chemical safety assessmentA chemical safety assessment according to the rules stipulated in REACH directive has been performed. The appendices provide anoverview of the risk management measures as based on this assessment.SECTION 16 : OTHER INFORMATIONSince the user's working conditions are not known by us, the information supplied on this safety data sheet is based on our current level of knowledge and on national and community regulations.It is at all times the responsibility of the user to take all necessary measures to comply with legal requirements and local regulations.The information in this safety data sheet must be regarded as a description of the safety requirements relating to the substance and not as a guarantee of the properties thereof.Abbreviations :DNEL : Derived No-Effect LevelADR : European agreement concerning the international carriage of dangerous goods by Road.IMDG : International Maritime Dangerous Goods.IATA : International Air Transport Association.ICAO : International Civil Aviation OrganisationRID : Regulations concerning the International carriage of Dangerous goods by rail.-M a d e u n d e r l i c e n c e o f E u r o p e a n L a b e l S y s t e m ?M S D S s o f t w a r e f r o m I n f o D y n e -h t t p : / / w w w . i n f o d y n e . f r -。
a r X i v :a s t r o -p h /0107269v 1 16 J u l 2001Astronomy &Astrophysics manuscript no.(will be inserted by hand later)Carbon Monoxide in type II supernovae ⋆J.Spyromilio,B.Leibundgut and R.GilmozziEuropean Southern Observatory,Karl-Schwarzschild-Strasse 2,Garching,D-85748,Germany e-mail:jspyromi@,bleibundgut@,rgilmozz@ Received ;acceptedAbstract.Infrared spectra of two type II supernovae 6months after explosion are presented.The spectra exhibit a strong similarity to the observations of SN 1987A and other type II SNe at comparable epochs.The continuum can be fitted with a cool black body and the hydrogen lines have emissivities that are approximately those of a Case B recombination spectrum.The data extend far enough into the thermal region to detect emission by the first overtone of carbon monoxide.The molecular emission is modeled and compared with that in the spectra of SN 1987A.It is found that the flux in the CO first overtone is comparable to that found in SN 1987A.We argue that Carbon Monoxide forms in the ejecta of all type II SNe during the first year after explosion.Key words.molecular processes -Supernovae:individual:SN 1998dl ;SN 1999em1.IntroductionThe presence of molecular emission in the spectra of super-novae while not new remains rarely detected.First detec-tion of carbon monoxide in a supernova was in the spec-tra of SN 1987A (Catchpole &Glass 1987,McGregor &Hyland 1987,Ames Research Center 1987,Oliva et al.1987,Spyromilio et al.1988).In SN 1987A observations of the first overtone of CO at 2.3-µm were complemented by observations at 4.6-µm of the fundamental bands.In addition to carbon monoxide,the spectra of SN 1987A re-vealed bands of SiO (Meikle et al.1993;Roche et al.1991)and CS (Meikle et al.1993).The presence of H +3is also claimed in the spectra of SN 1987A (Miller et al.1992)although alternative atomic species can also explain the identified features.Spyromilio &Leibundgut (1996)re-ported the detection of CO first overtone emission in the spectra of the type II supernova 1995ad while Gerardy et al.(2000)and Fassia et al.(2000)reported the presence of CO in SN 1998S.The formation of molecules in the ejecta of supernovae,even CO -the most stable of diatomic molecules with a dissociation energy of 11.09eV (Douglas &Møller 1955),is not trivial.The high UV field due to recombinations and the energetic electrons from the radioactive decays of 56Ni and its daughter 56Co create an inhospitable environ-ment with multiple dissociation paths (see Lepp,Dalgarno &McCray 1990).The presence therefore of moleculesin2J.Spyromilio,B.Leibundgut and R.Gilmozzi:CO in type II SNelines in early optical spectra classifying the object as a type II supernova.SN1998dl was observed at the ESO 3.58-m New Technology Telescope on La Silla,on1999January1,at an age of approximately150days.The near-infrared cam-era and spectrograph SofI(Moorwood et al.1999)was used for these observations.The red low-resolution grism was used for the H and K band spectra.While the grism does cover the region between1.8and1.92µm the atmo-spheric transparency is very low and no useful data are available in this region.A1arcsecond slit was used which gives a resolution ofλ/∆λof650and a wavelength cov-erage from1.5µm to2.5-µm.The spectroscopic standard BS2290(Allen&Cragg1983)was used to remove atmo-spheric features and to correct for the spectral response of the instrument.The conditions were not photometric and therefore the absolutefluxing of the spectrum is arbitrary. The slit projects to3pixels on the detector oversampling the data.Narrow features,of order3pixels(e.g.the par-ticularly prominent feature at2µm),in the spectra are not real but result from incomplete corrections for atmo-spheric features.Supernova1999em in NGC1637(recession velocity 717kms−1)was discovered by Li(1999)from observations made,on1999October29,at the KAIT.Jha et al.(1999) and Deng et al.(1999)classified the object as a type II supernova based on spectroscopic observations.SN1999em was observed,on2000April24,at an age of approximately170days with the same instrumental con-figuration as1998dl.The spectroscopic standard used in this case was HIP27855(Perryman et al.1997).The ac-curate removal of atmospheric features requires that the standard and the target are observed using the same re-solving power.The usage of a narrow slit in both observa-tions of the standard and the target implies that a sepa-rate photometric calibration of the data needs to be made to recover absolutefluxes.The imaging mode of SofI was used for this purpose and the NICMOS standard S121-E (Persson et al.1998)was used for the calibration.The de-rived K s magnitude of the supernova was15.1.The mean flux of the observed spectrum was corrected to the this magnitude.3.DiscussionThe spectra of SN1998dl and SN1999em are displayed in Figs.1and2,respectively.The data are shown at their observed wavelengths without correction for the recession velocity of the parent galaxies.The spectra are character-ized by a strong continuum upon which emission lines are superimposed.The strong Brackettγline(rest wavelength 2.1655µm)is evident.In the SN1999em data the shorter wavelength transitions of the Brackett series can also be seen.Long-wards of the Brγline,at2.21µm,a broad fea-ture identified by Meikle et al.(1989)in the spectra of SN1987A as emission by the2.207µm Na I4s2S–4p2P o multiplet is evident1.Starting at2.3µm and extending to the end of our spectral converage a broad feature is evi-dent in the data.This broad feature we attribute to carbon monoxidefirst overtone transitions(∆v=2).The much weaker second overtone(∆v=3)is expected to start at 1.5µm.Its contribution is expected to be only1.4%of the strength of thefirst overtone(Bouanich&Brodbeck 1974)and is therefore not detectable in our spectra.In much higher signal to noise data as would possibly be ob-tained at the VLT with ISAAC it might be possible to detect such emission.The fundamental(∆v=1)band at4.6µm is very much stronger than thefirst overtone observed here but also in an extremely unfavourable at-mospheric window.This fundamental band,as mentioned in the introduction,almost dominates the cooling of the ejecta for some time and observation would be of great in-terest.Unfortunately they are probably limited to a com-bination of the very biggest telescopes and the very nearest supernovae.A strong emission feature is observed at2µm.As noted above the narrow spike superimposed on the broad emis-sion is instrumental.In SN1987A,a broad feature at the same wavelength was identified by Meikle et al.as emission by the Ca I4p3P o–3d3D multiplet and the[Fe I]a5F5–a3F4 multiplet.Assuming a contribution to the2µm by[Fe I] in the spectrum of SN1998dl,the strong line at1.51µm could be identified as emission by the[Fe I]a5D−2–a5F4 multiplet.Alternatively Mg I also has a strong transition at1.5031µm.The lower recession velocity of the parent galaxy of SN1999em prevents us from detecting the same line in that spectrum.At2.06µm both in SN1998dl and SN1999em a small absorption is present.This we identify as the P-Cygni trough of the He I2s1S–2p1P o 2.058µm transition.We note that this region is one of poor atmospheric transmis-sion with a strong telluric CO2feature at2.06µm.While we believe that we have correctly compensated for this it is possible that the feature we identify as due to He I is due to poor cancellation by of aforementioned atmospheric feature.He I is expected to be very weak but its presence would be significant as highly excited He is a tracer for the presence of energetic electrons from the radioactive decay(Graham1988;Fassia&Meikle1999).The singlet transition observed here would need to develop sufficient optical depth to exhibit a P-Cygni trough.While transi-tions from2s1S to the ground state of He I are forbidden, depopulation of this energy level can occur via two photon decay with a low transition probability(A=51s−1).Given the age of the supernovae at the time of observation even this process would have de-populated the ground state of the2.058µm line.Recombinations are the obvious source of electrons which,as the transitions from the1P o states to the ground are expected to be saturated,will naturally cascade down to the2s1S level.Given the high ionization potential of He(24.587eV)the presence of the2.058µmJ.Spyromilio,B.Leibundgut and R.Gilmozzi:CO in type II SNe3 Fig.1.Spectrum of1998dl.Fig.2.Spectrum of1999em.transition suggests that the excitation by energetic elec-trons argued by Graham and Fassia&Meikle is occuringalso in these two SNe.We have used simple line models to makefits to thedata.Thesefits are shown in Figs.3and4.The ingredientsof the models are described below.The continuum in the models is a black-body witha temperature of3300K for SN1998dl and2000Kfor SN1999em.Theflux observed in the spectrum ofSN1999em at this temperature corresponds to a surfaceof last scattering expanding at500kms−1for170days ata distance of7.8Mpc(Sohn&Davidge1998).For the carbon monoxide a simple LTE(Boltzmanndistribution)model of the populations of the rotational-vibrational energy levels in the ground state electroniclevel1Σof12C16O(CO)was used.This model has beendescribed before in Spyromilio et al.(1988).Briefly,theenergy levels for a given rotational level J and a givenvibrational level v can be determined using:E=ω(v+12)2+ωy(v+13hg J(T M)2(2)whereνis the transition frequency,g J=2J+1andTM is the transition matrix from vibrational level v to v′.TM for∆J of±1is given by Chackerian&Tipping(1983)The lowest15vibrational levels were included and withineach110rotational level populations were calculated.As has been shown in the spectra of SN1987A(Spyromilio et al.1988)the CO band heads are sensitive tothe excitation temperature.Higher temperature in the COmodel increase the contribution of higher vibrational pairsand increase the emission long-wards of the v=2to v′=0band-head.The quality of the data is not good enoughto reliably distinguish between small changes in the tem-perature.The SN1998dl data indicate a slightly highertemperature than the SN1999em.Thefits use2500K forSN1998dl and2000K for SN1999em.The uncertainty inthese values is of order a few hundred degrees K.The dif-ference in the temperatures leads to a significantly differ-ent appearance of thefirst overtone emission.The2000Ktemperature for the SN1999em spectrum is based on theassumption that the drop influx long-wards of2.35µmis real.The SN1998dl spectra appear to show a muchsmoother decline towards longer wavelengths.The velocity at which the CO is expanding can be usedto constrain the mass of the progenitor(Gerardy et al.2000).In SN1998S Gerardy et al.derive a high expansionvelocity(v≈3000kms−1)based on the smooth rise of the2-0R-branch band head and a progenitor mass in excess of25M⊙.Fassia et al.(2000)do not detect such a steep riseand argue for a lower velocity.In addition their modelingof the ejecta favours a lower mass progenitor.We arguebelow in favour of the low range of velocities although we,like Gerardy et al.,have a smooth rise of the2-0R-branchband head.In the spectra of SN1987A a rigorousfitting of the ex-pansion velocity could be made(Spyromilio et al.1988)based on the appearance of the R-branch emission fromeach pair of energy states.Both Gerardy et al.(2000)andFassia et al.(2000)use the lack of clear separation of theR-branch band heads to place lower limits on the expan-sion velocity in the observations of SN1998S.This sameeffect can be used by us to place a weak lower limit of1000kms−1on the expansion velocity.The comparison of SN1998S with SN1987A(seeGerardy et al.Fig.6)shows that another line is possi-bly blended with the CO band head at2.28µm.This fea-ture,which at the recession velocity of SN1987A is ob-served at2.26µm,is discussed later but remains uniden-tified.The2.26µm feature is very strong in the spectra of4J.Spyromilio,B.Leibundgut and R.Gilmozzi:CO in type II SNeSN 1999em and weakly present in our data on SN 1998dl.The same feature waspresent in the spectra of SN 1995ad (Spyromilio &Leibundgut 1996).We cannot account for the lack of detection of this in the data of Fassia et al.(2000).The blending of this feature into the band head implies that models that do not take this into account will underestimate the true sharpness of the band head rise and derive higher than expected expansion velocities.The best estimate of the velocity of the CO,we believe,comes from the comparison of the observed spectra with those of SN 1987A (see Figs.5and 6).The good matching of the rise of the 2-0band head suggests that the veloc-ity observed in SN 1987A (1800–2000kms −1;Spyromilio et al.1988)is representative of the velocity of the CO in SN 1998dl and SN 1999em.Clearly in the absence of the blended line we would agree with Gerardy et al.(2000)and also derive a much higher expansion velocity for the CO.Each CO line in our models was convolved with a Gaussian line profile of FWHM 2000kms −1.The Brackett series line strengths in the model as-sume a case-B recombination spectrum at a temperature of 3000K and electron density of 105(Hummer &Storey 1987).The Br γand 9→4transitions are well fit using these parameters.The Br δline lies at the very edge of the atmospheric window and the cancellation of the at-mospheric features there is poor.While the norm would be not to display the spectra in this region due to the large uncertainties in the data we include them here.The data show that the spectra are consistent with the model.We do not derive any further information from the region around 1.92mu m.Unfortunately the Br ǫtransition lies in the gap between the two atmospheric windows and is not observable from the ground.The FWHM of the Gaussian line profile computed was 3000kms −1.As has been the case in the other SNe in which CO was detected,the ve-locity of the hydrogen lines is higher than that of the CO.The individual lines identified earlier as Na I ,Ca I and [Fe I ]have not been included in the displayed fits as the individual contributions of the species would be arbitrary.As already discussed with respect to the expansion ve-locity,the observations presented here can be compared with the observations of SN 1987A (data from Meikle et al.1989).Fig.5shows the data from SN 1987A taken at an age of 192days superimposed on the spectra of SN 1998dl.The SN 1987A data have been scaled to match the flux in the CO feature and red-shifted to the recession velocity of NGC1084.The continuum underlying the SN 1987A data has been artificially adjusted to match the average con-tinuum level in the SN 1998dl data.The SN 1998dl con-tinuum is much bluer than that of SN 1987A at the epoch at which the comparison data are taken.The poor correla-tion at 2.25µm is partially due to this effect and partially due to the difference in the strength of the 2.26µm feature.Given the quality of the SN 1998dl data,this comparison,adds plausibility to the identification of CO in the spec-tra.Also as mentioned above it allows a more accurate determination of the velocity structure of CO than can be achieved from the models.A similar comparison is madeFig.3.Spectrum of 1998dl and model.Features discussed in the text are identified in the figure.Fig.4.Spectrum of 1999em and model.Features dis-cussed in the text are identified in the figure.in Fig.6for SN 1999em using SN 1987A data obtained at an age of 255days.The flux within the CO emission band for SN 1999em is 5.5×10−11ergs/s/cm 2which at the distance of NGC 1637(7.8Mpc;Sohn &Davidge 1998)is 20%lower than that of SN 1987A at a comparable epoch.The mass that corresponds to this emission depends critically on the emission model.Our LTE model gives masses of order 10−4M ⊙.Liu &Dalgarno 1995predict a much higher mass (∼10−3M ⊙)for the same emission at this age and argue that the conditions within the ejecta favour the formation of this amount of CO.In fact it is expected that significantly more CO formed during the youth of the supernova (≈100days after explosion)but has been destroyed.Gearhart,Wheeler &Swartz 1999favour the formation of much less CO than Liu &Dalgarno and more in line with our mass estimates.Both GerardyJ.Spyromilio,B.Leibundgut and R.Gilmozzi:CO in type II SNe5Fig.5.Spectrum of 1998dl in the K band with spectrum of SN1987Asuperimposed.Fig.6.Spectrum of 1999em in the K band with spectrum of SN1987A superimposed.Note that the feature marked as CO +is much weaker in 87A than in 99em.et al.(2000)and Fassia et al.(2000)employ non-LTE and optically thick models to estimate the mass of CO emitting and derive high masses.These models base their input on assumptions and parameters that cannot be derived from our limited observations and even in the case of SN 1998S are based on assumed filling factors.Moreover Gerardy et al.argue that their comparisons are more a proof of prin-ciple rather than true models.We restrict ourselves there-fore to our comparison with SN plications due to clumping and asphericity are beyond the scope of this work to address but it is worth noting that polarization has been detected in the spectra of SN 1999em (Leonard,Filippenko &Chornock 1999;Wang et al.1999).Sollerman et al.(2001)detected no sign of dust in spec-troscopic observations of SN 1999em obtained at an age of 450days.While the formation of molecules may providethe cold sites for dust formation in the ejecta of type II su-pernovae and therefore may be a necessary precondition,it is clearly not sufficient.The feature at 2.26-µm short-wards of the CO v =2→0band head remains unidentified.The formation of suffi-cient CO +,whose first overtone v =2→0band head co-incides with this feature,is excluded by both Gearhart et al.and Liu &Dalgarno.Note,however,that Petuchowski et al.1989have argued that CO +could form in suffi-cient quantities.The feature was reported by and iden-tified as CO +by Spyromilio et al.(1988)and reported by Spyromilio &Leibundgut in the spectra of SN 1995ad.It is also observed by Gerardy et al.(2000)in SN 1998S.Fassia et al.(2000)did not detect the emission in their spectra of SN 1998S.While theoretical models fail to pre-dict the necessary amounts of CO +the identification of this feature remains insecure.4.ConclusionsThe spectra presented in this paper combined with the ob-servations presented by Spyromilio &Leibundgut (1996),Gerardy et al.(2000)and Fassia et al.(2000)suggest that the formation of CO in the ejecta of type II supernovae is ubiquitous at an age of 3to 6months.The mass of CO present in the ejecta is difficult to es-timate accurately.Our LTE models while simplistic rely on few assumptions with respect to the distribution and excitation of the CO.While for well studied supernovae such as SN 1987A the much more detailed models of Lepp,Dalgarno and McCray (1990)are well justified,it is ar-guable whether the input parameters for such models are well enough constrained in the case of the objects de-scribed here.We therefore argue that since the absolute fluxes argee for SN 1987A and SN 1999em so,to first ap-proximation,will the emitting masses.The expansion velocity of the CO is not accurately determined.By comparison with SN 1987A we argue that velocities around 2000kms −1are consistent with our data.We also argue that the blending of the ubiquitous (in our data)feature at 2.26µm with the 2-0R branch band head has to be taken into account when using this profile for velocity determinations.We note that comparing the spectra of the four other supernovae with CO emission with those of SN 1987A it is consistently the case that the spectral signature of the emission resembles that of SN 1987A at a later age than that at which the other SNe are observed.The other aspects of our data indicate that the spectra of type II SNe in the near IR are very similar and that recombination continues to play a major role even 5to 6months after explosion.A better understanding of the physical conditions in the ejecta of supernovae can be achieved with higher qual-ity infrared data as would be obtained with ISAAC at the VLT.Very high quality data may even constrain the iso-topic ratios of carbon and oxygen as the wavelengths of the band heads to shift depending on the exact isotopes.6J.Spyromilio,B.Leibundgut and R.Gilmozzi:CO in type II SNe Acknowledgements.We thank the staffat the NTT for theirexcellent support over many years of observing.We thankDavid Silva for outNEDing NED.This research has 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