Highly-Efficient-Saturated-PA-Design-Using-MWO

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How
do you distinguish steel from cast iron? How do you distinguish low alloy steel from high alloy steel?
1.1.1 Iron and Steel
The earth contains a large number of metals which are useful to man. One of the most important of these is iron. Modern industry needs considerable quantities of this metal, either in the form of iron or in the form of steel.
Mechanical Engineering materials
Organic polymer materials Inorganic non-metallic materials
plastic rubber Synthetic Fibers Traditional ceramics Special Ceramics Metal Matrix Composites
1.1.1 Iron and Steel
The ore becomes molten, and its oxides combine with carbon from the coke. The non-metallic constituents of the ore combine with the limestone to form a liquid slag. This floats on top of the molten iron, and passed out of the furnace through a tap. The metal which remains is pig iron.

206 EATON - EMERGENCY LIGHTING CPS全球目录2020版7指南 Led

7GuideLed SL 13011.1, 13021.1 CG-SSafety Luminaires for Escape Route Lighting* D egree of protection of the luminaire: IP41Degree of protection of module enclosure: IP20GuideLed SL 13011.1, 13021.1 CG-S• Safety luminaire with LED technology for recessed mounting• Unobtrusive. discrete appearance with round design and low installation depth of only 40 mm• Conversion to square design with optional bezel to fit to the ceiling plan if necessary• Special LED optics ensure especially efficient escape route illuminationor uniform anti-panic illumination• High Spacing by exact light direction and highly-efficient HighPowerLEDs• Up to 27 m from luminaire to luminaire with optics for escape route illumination• Up to 12 m from luminaire to luminaire with optics for antipanic illumination• Minimum service requirement due to high service life of the LEDs (up to 50.000 hours)Luminous flux ΦN Asymmetric optics 250 lmSymmetric optics 250 lmLuminous flux ΦE/ΦNat end of rated operating timer 100%Housing material PC. aluminiumHousing colour White RAL 9016Weight0.25 kgType of mounting Recessed mountingTerminals Clamp terminal 2 x 3 x 2.5 mm²Connection voltage220 – 240 V AC. 50/60 Hz176 – 275 V DCCurrent consumption - battery operation (220 V)20 mAPower consumption mains operation(apparent power/effective power)8.0 VA / 3.9 WInrush current1.5 APermissible ambient temperature-20°C to +40°CLight source HighPower LED 1 x 2 WOrdering detailsT ype Scope of supply Order No.GuideLed SL 13011.1 CG-S GuideLed SL 13011.1 CG-S. recessed mounting withasymmetric optics for escape route illumination. LEDsupply and CG-S technology (20 addresses) inhousing* with strain relief40071354480GuideLed SL 13021.1 CG-S GuideLed SL 13021.1 CG-S. recessed mounting with40071354481 GuideLed SL 13011.1 CG-SGuideLed SL 13021.1 CG-SLight distribution curveGuideLed SL 13011.1 CG-S recessedwith asymmetric opticsLight distribution curveGuideLed SL 13021.1 CG-S recessedwith symmetric opticsOrientation ofescape routeModule housing*Dimensions in mm7GuideLed SL 13011.1, 13021.1, 13012.1, 13022.1 CG-SSafety Luminaires for Escape Route LightingPlanning assistance for GuideLed SL CG-S with asymmetric optics for E = 1.0 lx (0.5 lx)Measuring height 0.02 m. maintenance factor MF = 80 %. battery operation3.0Escape route 2.3 (3.2) 6.4 (9.2) 7.3 ( 8.1)16.1 (17.8)3.5centre 2.3 (3.2) 6.5 (9.7) 8.1 ( 9.0)17.9 (19.9)4.0 2.3 (3.3) 6.5 (9.4) 8.8 ( 9.9)19.7 (21.9)4.5 2.3 (3.3) 6.6 (9.1) 9.5 (10.7)21.4 (23.7)5.0 2.2 (3.3)6.6 (9.2)10.0 (11.5)23.0 (25.6)5.5 2.1 (3.3)6.6 (9.2)10.4 (12.2)24.4 (27.4)6.0 2.0 (3.3) 6.5 (9.3)10.7 (12.9)25.8 (29.1)6.51.9 (3.2) 6.4 (9.4)7.9 (13.5)27.0 (30.8)7.01.8 (3.1) 6.2 (9.4) 7.6 (14.0)26.0 (32.3)7.5 1.7 (3.1) 6.1 (9.3) 7.3 (14.5)25.9 (33.7)8.01.6 (2.9) 5.8 (9.3) 7.0 (14.8)26.2 (35.2)8.51.4 (2.8) 5.7 (9.3) 6.7 (15.1)26.4 (36.6)9.01.2 (2.8) 5.5 (9.1) 6.1 (14.9)26.1 (37.8)9.51.0 (2.7) 5.3 (9.0) 4.7 (10.9)21.9 (37.6)10.00.6 (2.5) 5.0 (8.8) 2.5 (10.7)21.4 (36.7)Planning assistance for GuideLed SL CG-S with symmetric optics for E = 1.0 lx (0.5 lx)Measuring height 0.02 m. maintenance factor MF = 80 %. battery operation4.5 2.9 (6.6)13.0 (16.4) 3.2 (6.6)12.7 (16.4)5.0 2.4 (6.2)12.3 (17.4) 2.4 (6.4)12.4 (17.4)5.51.9 (5.3)10.6 (17.5)1.8 (5.5)11.0 (17.6)6.00.7 (4.7) 9.4 (17.8)0.9 (4.8) 9.6 (17.9)2.5Ceiling mounting 4.1 (4.6) 9.6 (10.3) 4.3 (4.7) 9.6 (10.3)3.0Room illumination4.5 (5.2)11.1 (12.0) 4.6 (5.2)11.0 (11.9)3.54.8 (5.6)12.1 (13.6) 5.1 (5.8)12.2 (13.5)4.0 3.2 (5.9)12.1 (15.0) 3.1 (6.3)12.3 (15.0)4.5 2.7 (6.2)12.6 (16.3) 2.6 (6.5)12.5 (16.3)5.0 2.5 (6.5)12.1 (17.2) 2.5 (6.8)12.4 (17.4)5.50.7 (4.3)11.6 (17.2)0.6 (4.5)11.7 (17.6)6.00.6 (3.5)11.9 (17.4)0.5 (3.7)11.8 (17.5)6.50.6 (2.8)12.0 (17.8)0.5 (1.1)11.9 (18.0)7.00.6 (3.1)11.7 (17.3)0.6 (0.7)11.8 (17.7)7.50.5 (3.5)11.3 (16.6)0.6 (0.6)11.4 (16.6)8.00.5 (0.8)10.9 (16.6)0.6 (0.5)10.9 (16.6)8.51.0 (1.0) 9.3 (16.7)1.0 (0.5) 9.3 (16.8)9.00.9 (1.2) 8.3 (16.9)1.0 (0.5) 8.3 (16.9)9.50.6 (1.5) 7.0 (16.9)0.6 (0.5) 7.1 (16.8)10.00.6 (1.5) 5.8 (16.6)0.6 (0.5) 5.8 (16.6) Escape route illuminationwith asymmetric opticsEscape route illuminationwith symmetric opticsRoom illuminationwith symmetric optics。

HIGHLY-POROUS CERAMIC CONDUCTORS AND METHOD OF MAK

专利名称：HIGHLY-POROUS CERAMIC CONDUCTORS AND METHOD OF MAKING THEM发明人：HENRI CARBONNEL,LUDOVIC HAMON申请号：AU5030172申请日：19721220公开号：AU5030172A公开日：19740620专利内容由知识产权出版社提供摘要：1414178 Sintered borides and silicides GROUPEMENT POUR LES ACTIVITES ATOMIQUES ET AVANLEES 21 Dec 1972 [22 Dec 1971] 59258/72 Heading C7D A sintered porous body is made from a mixture of (1) a fine non-sintered diboride powder of a Group IVA, VA or VIA metal with e.g. 20-80 per cent weight of a crushed diboride powder of a Group IVA, VA or VIA metal which has been hot pressed e.g. at 1000-2000‹C and (2) 1-6 per cent weight of a fluoride of a group 1A or 1B metal. The mixture is inbrated in a diee.g. graphite and sintered for at least 1 hour at 1000- 1500‹C in an inert gas such as argon. Up to 25% of a disilicide of a Group IVA, VA or VIA metal may be added to the diboride powder before hot pressing non-sintered disilicide powder may be added to the non-sintered diboride and the fluoride flux used is preferably Li F. The sintered body may be used in liquid metal pumps, electrodes for electrolysis and for resistance heating elements.申请人：HENRI CARBONNEL,LUDOVIC HAMON更多信息请下载全文后查看。

211050371_正负压一体式无空气X_射线光电子能谱原位转移仓的开发及研制

第 29 卷第 1 期分析测试技术与仪器Volume 29 Number 1 2023年3月ANALYSIS AND TESTING TECHNOLOGY AND INSTRUMENTS Mar. 2023大型仪器功能开发(30 ~ 36)正负压一体式无空气X射线光电子能谱原位转移仓的开发及研制章小余，赵志娟，袁　震，刘　芬（中国科学院化学研究所，北京　100190）摘要：针对空气敏感材料的表面分析，为了获得更加真实的表面组成与结构信息，需要提供一个可以保护样品从制备完成到分析表征过程中不接触大气环境的装置. 通过使用O圈密封和单向密封柱，提出一种简便且有效的设计概念，自主研制了正负压一体式无空气X射线光电子能谱（XPS）原位转移仓，用于空气敏感材料的XPS测试，利用单向密封柱实现不同工作需求下正负压两种模式的任意切换. 通过对空气敏感的金属Li片和CuCl粉末进行XPS分析表明，采用XPS原位转移仓正压和负压模式均可有效避免样品表面接触空气，保证测试结果准确可靠，而且采用正压密封方式转移样品可以提供更长的密封时效性. 研制的原位转移仓具有设计小巧、操作简便、成本低、密封效果好的特点，适合给有需求的用户开放使用.关键词：空气敏感；X射线光电子能谱；原位转移；正负压一体式中图分类号：O657; O641; TH842 文献标志码：B 文章编号：1006-3757（2023）01-0030-07 DOI：10.16495/j.1006-3757.2023.01.005Development and Research of Inert-Gas/Vacuum Sealing Air-Free In-Situ Transfer Module of X-Ray Photoelectron SpectroscopyZHANG Xiaoyu， ZHAO Zhijuan， YUAN Zhen， LIU Fen（Institute of Chemistry Chinese Academy of Sciences, Beijing 100190, China）Abstract：For the surface analysis of air sensitive materials, and from the sample preparation to characterization, it is necessary to provide a device that can protect samples from exposing to the atmosphere environment so as to obtain accurate and impactful data of the surface chemistry. Through the use of O-ring and one-way sealing, a simple and effective design concept has been demonstrated, and an inert-gas/vacuum sealing air-free X-ray photoelectron spectroscopic (XPS) in-situ transfer module has been developed to realize the XPS analysis of air sensitive materials. The design of one-way sealing was achieved conveniently by switching between inert-gas and vacuum sealing modes in face of different working requirements. The XPS analysis of air-sensitive metal Li sheets and CuCl powders showed that both the sealing modes (an inert-gas/vacuum sealing) of the XPS in-situ transfer module can effectively avoid air contact on the sample surface, and consequently, can ensure the accuracy and reliability of XPS data. Furthmore, the inert gas sealing mode can keep the sample air-free for a longer time. The homemade XPS in-situ transfer module in this work is characterized by a compact design, convenient operation, low cost and effective sealing, which is suitable for the open access to the users who need it.收稿日期：2022−12−07；　修订日期：2023−01−17.基金项目：中国科学院化学研究所仪器孵化项目[Instrument and Device Functional Developing Project of Institute of Chemistry Chinese Academy of Sciences]作者简介：章小余（1986−），女，硕士，工程师，主要研究方向为电子能谱技术及材料表面分析，E-mail：xyiuzhang@ .Key words：air-sensitive；X-ray photoelectron spectroscopy；in-situ transfer；inert-gas/vacuum sealingX射线光电子能谱（XPS）是一种表面灵敏的分析技术，通常用于固体材料表面元素组成和化学态分析[1]. 作为表面分析领域中最有效的方法之一，XPS广泛应用于纳米科学、微电子学、吸附与催化、环境科学、半导体、冶金和材料科学、能源电池及生物医学等诸多领域[2-3]. 其中在催化和能源电池材料分析中，有一些样品比较特殊，比如碱金属电池[4-6]、负载型纳米金属催化剂[7-8]和钙钛矿材料[9]对空气非常敏感，其表面形态和化学组成接触空气后会迅速发生改变，直接影响采集数据的准确性和有效性，因此这类样品的表面分析测试具有一定难度. 目前，常规的光电子能谱仪制样转移过程通常是在大气环境中，将样品固定在标准样品台上，随后放入仪器进样室内抽真空至1×10−6 Pa，再转入分析室内进行测试. 这种制备和进样方式无法避免样品接触大气环境，对于空气敏感材料，其表面很容易与水、氧发生化学反应，导致无法获得材料表面真实的结构信息.为了保证样品表面状态在转移至能谱仪内的过程中不受大气环境影响，研究人员采用了各种技术来保持样品转移过程中隔绝空气. 比如前处理及反应装置与电子能谱仪腔室间真空传输[10-12]、外接手套箱 [13-14]、商用转移仓[15-16]、真空蒸镀惰性金属比如Al层（1.5~6 nm）[17]等. 尽管上述技术手段有效，但也存在一些缺点，例如配套装置体积巨大、试验过程不易操作、投入成本高等，这都不利于在普通实验室内广泛应用. 而一些电子能谱仪器制造商根据自身仪器的特点也研发出了相应配套的商用真空传递仓，例如Thermofisher公司研发的一种XPS 真空转移仓，转移过程中样品处于微正压密封状态，但其价格昂贵，体积较大，转移过程必须通过手套箱大过渡舱辅助，导致传递效率低，单次需消耗至少10 L高纯氩气，因此购置使用者较少，利用率低.另外有一些国内公司也研发了类似的商品化气体保护原位传递仓，采用微正压方式密封转移样品，但需要在能谱仪器进样室舱门的法兰上外接磁耦合机械旋转推拉杆，其操作复杂且放置样品的有效区域小，单次仅可放置尺寸为3 mm×3 mm的样品3～4个，进样和测试效率较低. 因此，从2016年起本实验团队开始自主研制XPS原位样品转移装置[18]，经过结构与性能的迭代优化[19]，最终研制出一种正负压一体式无空气XPS原位转移仓[20]（本文简称XPS原位转移仓），具有结构小巧、操作便捷、成本低、密封效果好、正压和负压密封两种模式转移样品的特点. 为验证装置的密封时效性能，本工作选取两种典型的空气敏感材料进行测试，一种是金属Li材料，其化学性质非常活泼，遇空气后表面迅速与空气中的O2、N2、S等反应导致表面化学状态改变. 另一种是无水CuCl粉末，其在空气中放置短时间内易发生水解和氧化. 试验结果表明，该XPS 原位转移仓对不同类型的空气敏感样品的无空气转移均可以提供更便捷有效的密封保护. 目前，XPS原位转移仓已在多个科研单位的实验室推广使用，支撑应用涉及吸附与催化、能源环境等研究领域.1　试验部分1.1　XPS原位转移仓的研制基于本实验室ESCALAB 250Xi型多功能光电子能谱仪器（Thermofisher 公司）的特点，研究人员设计了XPS原位转移仓. 为兼顾各个部件强度、精度与轻量化的要求，所有部件均采用钛合金材料.该装置从整体结构上分为样品台、密封罩和紧固挡板三个部件，如图1（a）~（c）所示. 在密封罩内部通过单向密封设计[图1（e）]使得XPS原位转移仓实现正负压一体，实际操作中可通过调节密封罩上的螺帽完成两种模式任意切换. 同时，从图1（e）中可以直观看到，密封罩与样品台之间通过O圈密封，利用带有螺钉的紧固挡板将二者紧密固定. 此外，为确保样品台与密封罩对接方位正确，本设计使用定向槽定位样品台与密封罩位置，保证XPS原位转移仓顺利传接到仪器进样室.XPS原位转移仓使用的具体流程：在手套箱中将空气敏感样品粘贴至样品台上，利用紧固挡板使样品台和密封罩固定在一起，通过调节密封罩上的螺帽将样品所在区域密封为正压惰性气氛（压强为300 Pa、环境气氛与手套箱内相同）或者负压真空状态，其整体装配实物图如图1（d）所示. 该转移仓结构小巧，整体尺寸仅52 mm×58 mm×60 mm，可直接放入手套箱小过渡舱传递. 由于转移仓尺寸小，其第 1 期章小余，等：正负压一体式无空气X射线光电子能谱原位转移仓的开发及研制31原料成本大大缩减，整体造价不高. 转移仓送至能谱仪进样室后，配合样品停放台与进样杆的同时双向对接，将转移仓整体固定在进样室内，如图1（f ）所示. 此时关闭进样室舱门开始抽真空，当样品台与密封罩内外压强平衡后密封罩自动解除真空密封，但仍然处于O 圈密闭状态. 等待进样室真空抽至1×10−4Pa 后，使用能谱仪进样室的样品停放台摘除脱离的密封罩[如图1（g ）所示]，待真空抽至1×10−6Pa ，即可将样品送入分析室进行XPS 测试.整个试验过程操作便捷，实现了样品从手套箱转移至能谱仪内不接触大气环境.1.2　试验过程1.2.1　样品准备及转移试验所用手套箱是布劳恩惰性气体系统（上海）有限公司生产，型号为MB200MOD （1500/780）NAC ；金属Li 片购自中能锂业，纯度99.9%；CuCl 购自ALFA 公司，纯度99.999%.金属Li 片的制备及转移：将XPS 原位转移仓整体通过手套箱过渡舱送入手套箱中，剪取金属Li 片用双面胶带固定于样品台上，分别采用正压、负压两种密封模式将XPS 原位转移仓整体从手套箱中取出，分别在空气中放置0、2、4、8、18、24、48、72 h 后送入能谱仪内，进行XPS 测试.CuCl 粉末的制备及转移：在手套箱中将CuCl 粉末压片[21]，使用上述同样的制备方法，将XPS 原位转移仓整体在空气中分别放置0、7、24、72 h 后送入能谱仪内，进行XPS 测试.1.2.2　样品转移方式介绍样品在手套箱中粘贴完成后，分别采用三种方式将其送入能谱仪. 第一种方式是在手套箱内使用标准样品台粘贴样品，将其装入自封袋密封，待能谱仪进样室舱门打开后，即刻打开封口袋送入仪器中开始抽真空等待测试，整个转移过程中样品暴露空气约15 s. 第二种方式是使用XPS 原位转移仓负压密封模式转移样品，具体操作步骤：利用紧固挡板将样品台和密封罩固定在一起，逆时针（OPEN ）旋动螺帽至顶部，放入手套箱过渡舱并将其抽为真空，此过程中样品所在区域也抽至负压. 取出整体装置后再顺时针（CLOSE ）旋动螺帽至底部，将样品所在区域进一步锁死密封. 样品在负压环境中转移至XPS 实验室，拆卸掉紧固挡板，随即送入能谱仪进样室内. 第三种方式是使用XPS 原位转移仓正压密封模式转移样品，具体操作步骤：利用紧固挡板将样品台和密封罩固定在一起，顺时针（CLOSE ）旋螺帽抽气管限位板单向密封柱密封罩主体O 圈样品台紧固挡板(e) 密封罩对接停放台机械手样品台对接进样杆(a)(b)(c)(d)(g)图1　正负压一体式无空气XPS 原位转移仓系统装置（a ）样品台，（b ）密封罩，（c ）紧固挡板，（d ）整体装配实物图，（e ）整体装置分解示意图，（f ）样品台与密封罩在进样室内对接完成，（g ）样品台与密封罩在进样室内分离Fig. 1　System device of inert-gas/vacuum sealing air-free XPS in-situ transfer module32分析测试技术与仪器第 29 卷动螺帽至底部，此时样品所在区域密封为正压惰性气氛. 直至样品转移至XPS 实验室，再使用配套真空抽气系统（如图2所示），通过抽气管将样品所在区域迅速抽为负压，拆卸掉紧固挡板，随即送入能谱仪进样室内.图2　能谱仪实验室内配套真空抽气系统Fig. 2　Vacuum pumping system in XPSlaboratory1.2.3　XPS 分析测试试验所用仪器为Thermo Fisher Scientific 公司的ESCALAB 250Xi 型多功能X 射线光电子能谱仪，仪器分析室基础真空为1×10−7Pa ，X 射线激发源为单色化Al 靶（Alk α，1 486.6 eV ），功率150 W ，高分辨谱图在30 eV 的通能及0.05 eV 的步长等测试条件下获得，并以烃类碳C 1s 为284.8 eV 的结合能为能量标准进行荷电校正.2　结果与讨论2.1　测试结果分析为了验证XPS 原位转移仓的密封性能，本文做了一系列的对照试验，选取空气敏感的金属Li 片和CuCl 粉末样品进行XPS 测试，分别采用上述三种方式转移样品，并考察了XPS 原位转移仓密封状态下在空气中放置不同时间后对样品测试结果的影响.2.1.1　负压密封模式下XPS 原位转移仓对金属Li片的密封时效性验证将金属Li 片通过两种（标准和负压密封）方式转移并在空气中放置不同时间，对这一系列样品进行XPS 测试，Li 1s 和C 1s 高分辨谱图结果如图3（a ）（b ）所示，试验所测得的Li 1s 半峰宽值如表1所列. 根据XPS 结果分析，金属Li 片采用标准样品台进样（封口袋密封），短暂暴露空气约15 s ，此时Li 1s 的半峰宽为1.62 eV. 而采用XPS 原位转移仓负压密封模式转移样品时，装置整体放置空气18 h 内，Li 1s 的半峰宽基本保持为（1.35±0.03） eV. 放置空气24 h 后，Li 1s 的半峰宽增加到与暴露空气15 s 的金属Li 片一样，说明此时原位转移仓的密封性能衰减，金属Li 片与渗入内部的空气发生反应生成新物质导致Li 1s 半峰宽变宽. 由图3（b ）中C 1s 高分辨谱图分析，结合能位于284.82 eV 的峰归属为C-C/污染C ，位于286.23 eV 的峰归属为C-OH/C-O-CBinding energy/eVI n t e n s i t y /a .u .Li 1s半峰宽增大暴露 15 s密封放置 24 h 密封放置 18 h 密封放置 8 h 密封放置 4 h 密封放置 0 h6058565452Binding energy/eVI n t e n s i t y /a .u .C 1s(a)(b)暴露 1 min 暴露 15 s 密封放置 24 h 密封放置 18 h 密封放置 0 h292290288284282286280图3　金属Li 片通过两种（标准和负压密封）方式转移并在空气中放置不同时间的（a ）Li 1s 和（b ）C 1s 高分辨谱图Fig. 3　High-resolution spectra of (a) Li 1s and (b) C 1s of Li sheet samples transferred by two methods (standard andvacuum sealings) and placed in air for different times第 1 期章小余，等：正负压一体式无空气X 射线光电子能谱原位转移仓的开发及研制33键，位于288.61~289.72 eV的峰归属为HCO3−/CO32−中的C[22]. 我们从C 1s的XPS谱图可以直观的看到，与空气短暂接触后，样品表面瞬间生成新的结构，随着暴露时间增加到1 min，副反应产物大量增加（HCO3−/CO32−）. 而XPS原位转移仓负压密封模式下在空气中放置18 h内，C结构基本不变，在空气中放置24 h后，C结构只有微小变化. 因此根据试验结果分析，对于空气极其敏感的材料，在负压密封模式下，建议XPS原位转移仓在空气中放置时间不要超过18 h. 这种模式适合对空气极其敏感样品的短距离转移.表 1 通过两种（标准和负压密封）方式转移并在空气中放置不同时间的Li 1s的半峰宽Table 1　Full width at half maxima (FWHM) of Li 1stransferred by two methods (standard and vacuum sealings) and placed in air for different times样品说明进样方式半峰宽/eV密封放置0 h XPS原位转移仓负压密封模式转移1.38密封放置2 h同上 1.39密封放置4 h同上 1.36密封放置8 h同上 1.32密封放置18 h同上 1.32密封放置24 h同上 1.62暴露15 s标准样品台进样（封口袋密封）1.622.1.2　正压密封模式下原位转移仓对金属Li片的密封时效性验证将金属Li片通过两种（标准和正压密封）方式转移并在空气中放置不同时间，对这一系列样品进行XPS测试，Li 1s高分辨谱图结果如图4所示，所测得的Li 1s半峰宽值如表2所列. 根据XPS结果分析，XPS原位转移仓正压密封后，在空气中放置72 h内，Li 1s半峰宽基本保持为（1.38±0.04） eV，说明有明显的密封效果，金属Li片仍然保持原有化学状态. 所以对于空气极其敏感的材料，在正压密封模式下，可至少在72 h内保持样品表面不发生化学态变化. 这种模式适合长时间远距离（可全国范围内）转移空气敏感样品.2.1.3　负压密封模式下XPS原位转移仓对空气敏感样品CuCl的密封时效性验证除了金属Li片样品，本文还继续考察XPS原位转移仓对空气敏感样品CuCl的密封时效性. 图5为CuCl粉末通过两种（标准和负压密封）方式转移并在空气中放置不同时间的Cu 2p高分辨谱图. XPS谱图中结合能[22]位于932.32 eV的峰归属为Cu+的Cu 2p3/2，位于935.25 eV的峰归属为Cu2+的Cu 2p3/2，此外，XPS谱图中位于940.00~947.50 eV 处的峰为Cu2+的震激伴峰，这些震激伴峰被认为是表 2 通过两种（标准和正压密封）方式转移并在空气中放置不同时间的Li 1s的半峰宽Table 2　FWHM of Li 1s transferred by two methods(standard and inert gas sealings) and placed in air fordifferent times样品说明进样方式半峰宽/eV 密封放置0 h XPS原位转移仓正压密封模式转移1.42密封放置2 h同上 1.35密封放置4 h同上 1.35密封放置8 h同上 1.34密封放置18 h同上 1.38密封放置24 h同上 1.39密封放置48 h同上 1.42密封放置72 h同上 1.38暴露15 s标准样品台进样（封口袋密封）1.62Binding energy/eVIntensity/a.u.Li 1s半峰宽比正压密封的宽半峰宽=1.62 eV半峰宽=1.38 eV暴露 15 s密封放置 72 h密封放置 48 h密封放置 24 h密封放置 18 h密封放置 0 h605856545250图4　金属Li片通过两种（标准和正压密封）方式转移并在空气中放置不同时间的Li 1s高分辨谱图Fig. 4　High-resolution spectra of Li 1s on Li sheet samples transferred by two methods (standard and inert gas sealings) and placed in air for different times34分析测试技术与仪器第 29 卷价壳层电子向激发态跃迁的终态效应所产生[23]，而在Cu +和Cu 0中则观察不到.根据XPS 结果分析，CuCl 在XPS 原位转移仓保护（负压密封）下，即使放置空气中72 h ，测得的Cu 2p 高分辨能谱图显示只有Cu +存在，说明CuCl 并未被氧化. 若无XPS 原位转移仓保护，CuCl 粉末放置空气中3 min 就发生了比较明显的氧化，从测得的Cu 2p 高分辨能谱图能够直观的看到Cu 2+及其震激伴峰的存在，并且随着放置时间增加到40 min ，其氧化程度也大大增加. 因此，对于空气敏感的无机材料、纳米催化剂和钙钛矿材料等，采用负压密封模式转移就可至少在72 h 内保持样品表面不发生化学态变化.3　结论本工作中自主研制的正负压一体式无空气XPS原位转移仓在空气敏感样品转移过程中可以有效隔绝空气，从而获得样品最真实的表面化学结构.试验者可根据样品情况和实验室条件选择转移模式，并在密封有效时间内将样品从实验室转移至能谱仪中完成测试. 综上所述，该XPS 原位转移仓是一种设计小巧、操作简便、密封性能优异、成本较低的样品无水无氧转移装置，因此非常适合广泛开放给有需求的试验者使用. 在原位和准原位表征技术被广泛用于助力新材料发展的现阶段，希望该设计理念能对仪器功能的开发和更多准原位表征测试的扩展提供一些启示.参考文献：黄惠忠. 论表面分析及其在材料研究中的应用[M ].北京: 科学技术文献出版社, 2002: 16-18.［ 1 ］杨文超, 刘殿方, 高欣, 等. X 射线光电子能谱应用综述[J ]. 中国口岸科学技术，2022，4（2）：30-37.[YANG Wenchao, LIU Dianfang, GAO Xin, et al.TheapplicationofX -rayphotoelectronspectroscopy [J ]. China Port Science and Technology ，2022，4 （2）：30-37.]［ 2 ］郭沁林. X 射线光电子能谱[J ]. 物理，2007，36（5）：405-410. [GUO Qinlin. X -ray photoelectron spectro-scopy [J ]. Physics ，2007，36 （5）：405-410.]［ 3 ］Malmgren S, Ciosek K, Lindblad R, et al. Con-sequences of air exposure on the lithiated graphite SEI [J ]. Electrochimica Acta ，2013，105 ：83-91.［ 4 ］Zhang Y H, Chen S M, Chen Y, et al. Functional poly-ethylene glycol-based solid electrolytes with enhanced interfacial compatibility for room-temperature lithium metal batteries [J ]. Materials Chemistry Frontiers ，2021，5 （9）：3681-3691.［ 5 ］周逸凡, 杨慕紫, 佘峰权, 等. X 射线光电子能谱在固态锂离子电池界面研究中的应用[J ]. 物理学报，2021，70（17）：178801. [ZHOU Yifan, YANG Muzi,SHE Fengquan, et al. Application of X -ray photoelec-tron spectroscopy to study interfaces for solid-state lithium ion battery [J ]. Acta Physica Sinica ，2021，70（17）：178801.]［ 6 ］Huang J J, Song Y Y, Ma D D, et al. The effect of thesupport on the surface composition of PtCu alloy nanocatalysts: in situ XPS and HS-LEIS studies [J ].Chinese Journal of Catalysis ，2017，38 （7）：1229-1236.［ 7 ］Koley P, Shit S C, Sabri Y M, et al. Looking into moreeyes combining in situ spectroscopy in catalytic bio-fuel upgradation with composition-graded Ag-Co core-shell nanoalloys [J ]. ACS Sustainable Chemistry &Engineering ，2021，9 （10）：3750-3767.［ 8 ］Opitz A K, Nenning A, Rameshan C, et al. Enhancingelectrochemical water-splitting kinetics by polarization-driven formation of near-surface iron(0): an in situ XPS study on perovskite-type electrodes [J ]. Ange-wandte Chemie (International Ed in English)，2015，54（9）：2628-2632.［ 9 ］Czekaj I, Loviat F, Raimondi F, et al. Characterization［ 10 ］Binding energy/eVI n t e n s i t y /a .u .Cu 2pCu +Cu 2+暴露 3 min暴露 40 min 密封放置 7 h 密封放置 72 h 密封放置 24 h密封放置 0 h960950945935925955940930920图5　CuCl 粉末通过两种（标准和负压密封）方式转移并在空气中放置不同时间的Cu 2p 高分辨谱图Fig. 5　High-resolution spectra of Cu 2p on CuCl powder samples transferred by two methods (standard and vacuumsealings) and placed in air for different times第 1 期章小余，等：正负压一体式无空气X 射线光电子能谱原位转移仓的开发及研制35of surface processes at the Ni-based catalyst during the methanation of biomass-derived synthesis gas: X -ray photoelectron spectroscopy (XPS)[J ]. Applied Cata-lysis A:General ，2007，329 ：68-78.Rutkowski M M, McNicholas K M, Zeng Z Q, et al.Design of an ultrahigh vacuum transfer mechanism to interconnect an oxide molecular beam epitaxy growth chamber and an X -ray photoemission spectroscopy analysis system [J ]. Review of Scientific Instruments ，2013，84 （6）：065105.［ 11 ］伊晓东, 郭建平, 孙海珍, 等. X 射线光电子能谱仪样品前处理装置的设计及应用[J ]. 分析仪器，2008（5）：8-11. [YI Xiaodong, GUO Jianping, SUN Haizhen, et al. Design of a sample pretreatment device for X -ray photoelectron spectrometer [J ]. Analytical Instrumentation ，2008 （5）：8-11.]［ 12 ］Aurbach D, Weissman I, Schechter A, et al. X -ray pho-toelectron spectroscopy studies of lithium surfaces pre-pared in several important electrolyte solutions. A comparison with previous studies by Fourier trans-form infrared spectroscopy [J ]. Langmuir ，1996，12（16）：3991-4007.［ 13 ］Światowska-Mrowiecka J, Maurice V, Zanna S, et al.XPS study of Li ion intercalation in V 2O 5 thin films prepared by thermal oxidation of vanadium metal [J ].Electrochimica Acta ，2007，52 （18）：5644-5653.［ 14 ］Weingarth D, Foelske-Schmitz A, Wokaun A, et al. Insitu electrochemical XPS study of the Pt/[BF 4]system [J ]. Electrochemistry Communications ，2011，13 （6）：619-622.［ 15 ］Schneider J D, Agocs D B, Prieto A L. Design of asample transfer holder to enable air-free X -ray photo-electron spectroscopy [J ]. Chemistry of Materials ，2020，32 （19）：8091-8096.［ 16 ］Karamurzov B S, Kochur A G, Misakova L B, et al.Calculation of the pure surface composition of the bin-ary alloy according to XPS data obtained after the al-loy surface contact with air [J ]. Journal of Structural Chemistry ，2015，56 （3）：576-581.［ 17 ］章小余, 赵志娟. 一种半原位XPS 样品转移装置: 中国, 201620925237.5[P ]. 2017-02-15.［ 18 ］章小余, 袁震, 赵志娟. 一种半原位X 射线光电子能谱分析仪的样品转移装置: 中国, 201720056623.X [P ]. 2017-12-08.［ 19 ］袁震, 章小余, 赵志娟. 一种样品转移装置及转移方法: 中国, 2011203822.1[P ]. 2022-03-01.［ 20 ］刘芬, 赵志娟, 邱丽美, 等. XPS 分析固体粉末时的样品制备法研究[J ]. 分析测试技术与仪器，2007，13（2）：107-109. [LIU Fen, ZHAO Zhijuan, QIU Limei, et al. Study of sample preparation method for XPS analysis of powdered samples [J ]. Analysis and Testing Technology and Instruments ，2007，13 （2）：107-109.]［ 21 ］Wagner C D, Riggs W M, Davis L E, et al. Handbookof X -ray photoelectron spectroscopy [M ]. Eden Prair-ie, Minnesota, 1978.［ 22 ］Watts J F, Wolstenholme J. 表面分析(XPS 和AES)引论[M ]. 吴正龙, 译. 上海: 华东理工大学出版社,2008.［ 23 ］36分析测试技术与仪器第 29 卷。

g-C3N4

第42卷第10期2023年10月硅㊀酸㊀盐㊀通㊀报BULLETIN OF THE CHINESE CERAMIC SOCIETY Vol.42㊀No.10October,2023g-C 3N 4/Ag 基二元复合光催化剂降解环境污染物的研究进展柏林洋1,蔡照胜2(1.江苏旅游职业学院,扬州㊀225000;2.盐城工学院化学化工学院,盐城㊀224051)摘要:光催化技术在太阳能资源利用方面呈现出良好的应用前景,已受到世界各国的广泛关注㊂g-C 3N 4是一种二维结构的非金属聚合物型半导体材料,具有合成简单㊁成本低㊁化学性质稳定㊁无毒等特点,在环境修复和能量转化方面应用潜力较大㊂但g-C 3N 4存在对可见光吸收能力差㊁比表面积小和光生载流子复合速率高等缺点,限制了其实际应用㊂构筑异质结光催化剂是提高光催化效率的有效途径之一㊂基于Ag 基材料的特点,前人对g-C 3N 4/Ag 基二元复合光催化剂进行了大量研究,并取得显著成果㊂本文总结了近年来AgX(X =Cl,Br,I)/g-C 3N 4㊁Ag 3PO 4/g-C 3N 4㊁Ag 2CO 3/g-C 3N 4㊁Ag 3VO 4/g-C 3N 4㊁Ag 2CrO 4/g-C 3N 4㊁Ag 2O /g-C 3N 4和Ag 2MoO 4/g-C 3N 4复合光催化剂降解环境污染物的研究进展,并评述了g-C 3N 4/Ag 基二元复合光催化剂目前面临的主要挑战,展望了其未来发展趋势㊂关键词:g-C 3N 4;Ag 基材料;二元复合光催化剂;光催化性能;环境污染物中图分类号:TQ426㊀㊀文献标志码:A ㊀㊀文章编号:1001-1625(2023)10-3755-09Research Progress on g-C 3N 4/Ag-Based Binary Composite Photocatalysts for Degradation of Environmental PollutantsBAI Linyang 1,CAI Zhaosheng 2(1.Jiangsu Institute of Tourism,Yangzhou 225000,China;2.School of Chemistry and Chemical Engineering,Yancheng Institute of Technology,Yancheng 224051,China)Abstract :Photocatalysis technology shows a good application prospect in the utilization of solar energy resource and has attracted worldwide attention.g-C 3N 4is a two-dimensional polymeric metal-free semiconductor material with the characteristics of facile synthesis,low cost,high chemical stability and non-toxicity,which has great potential in environmental remediation and energy conversion.However,g-C 3N 4has the drawbacks of poor visible light absorption capacity,low specific surface area and high recombination rate of photogenerated charge carriers,which limits its practical application.Constructing heterojunction photocatalyst has become one of effective pathways for boosting photocatalytic efficiency.Based on the inherent merits of Ag-based materials,a lot of researches have been carried out on g-C 3N 4/Ag-based binary photocatalysts and prominent results have been achieved.Recent advances on AgX (X =Cl,Br,I)/g-C 3N 4,Ag 3PO 4/g-C 3N 4,Ag 2CO 3/g-C 3N 4,Ag 3VO 4/g-C 3N 4,Ag 2CrO 4/g-C 3N 4,Ag 2O /g-C 3N 4and Ag 2MoO 4/g-C 3N 4composite photocatalysts for the degradation of environmental pollutants were summarized.The major challenges of g-C 3N 4/Ag-based binary composite photocatalysts were reviewed and the future development trends were also forecast.Key words :g-C 3N 4;Ag-based material;binary composite photocatalyst;photocatalytic performance;environmental pollutant㊀收稿日期:2023-05-15;修订日期:2023-06-12基金项目:江苏省高等学校自然科学研究面上项目(19KJD530002)作者简介:柏林洋(1967 ),男,博士,副教授㊂主要从事光催化材料方面的研究㊂E-mail:linybai@通信作者:蔡照胜,博士,教授㊂E-mail:jsyc_czs@0㊀引㊀言随着全球经济的快速增长和工业化进程的加快,皮革㊁印染㊁制药和化工等行业排放的环境污染物总量3756㊀陶㊀瓷硅酸盐通报㊀㊀㊀㊀㊀㊀第42卷也不断增长㊂这些环境污染物存在成分复杂㊁毒性大㊁难以降解等特点,对人们的身体健康和生态环境产生严重威胁,已成为制约经济和社会发展的突出问题㊂如何实现环境污染物的高效降解是目前亟待解决的重要问题㊂效率低㊁能耗高及存在二次污染是利用传统处理方法处置环境污染物的主要缺陷[1]㊂光催化技术作为一种新型的绿色技术,具有环境友好㊁成本低㊁反应效率高和无二次污染等优点,在解决环境污染问题方面具有很大的发展潜力,深受人们的关注[2-4]㊂g-C3N4属于一种非金属聚合物型半导体材料,具有二维分子结构,即C原子和N原子通过sp2杂化形成的共轭石墨烯平面结构,具有适宜的禁带宽度(2.7eV)和对460nm以下可见光良好的响应能力㊂g-C3N4具有合成原料成本低㊁制备工艺简单㊁耐酸耐碱和稳定性好等特点,在催化[5]㊁生物[6]和材料[7]等领域应用广泛㊂然而,g-C3N4较小的比表面积㊁较弱的可见光吸收能力和较快的光生载流子复合率等不足导致其光量子利用率不高,给实际应用带来较大困难[8]㊂为了克服上述问题,前人提出了对g-C3N4进行形貌调控[9]㊁元素掺杂[10-11]和与其他半导体耦合[12-13]等方法㊂其中,将g-C3N4与其他半导体耦合形成异质结光催化剂最为常见㊂Ag基半导体材料因具有成本合理㊁光电性能好和光催化活性高等特点而深受青睐,但仍存在光生载流子快速复合和光腐蚀等缺陷㊂近年来,人们将Ag基材料与g-C3N4进行复合,整体提高了复合光催化剂的催化性能,并由此取得了大量极有价值的科研成果㊂本文综述了近年来g-C3N4/Ag银基二元复合光催化剂的制备方法㊁性能和应用等方面的研究现状,同时展望了未来的发展趋势,期望能为该领域的研究人员提供新的思路㊂1㊀g-C3N4/Ag基二元复合光催化剂近年来,基于Ag基半导体材料能与g-C3N4能带结构匹配的特点,构筑g-C3N4/Ag基异质结型复合光催化体系已成为国内外的研究热点㊂这类催化剂通常采用沉淀法在g-C3N4表面负载Ag基半导体材料㊂其中,Ag基体的成核和生长是关键问题㊂通过对Ag基材料成核和生长工艺的控制,实现了Ag基材料在g-C3N4上的均匀分布㊂此外,通过对g-C3N4微观结构进行调控,使其具有较大的比表面积和较高的结晶度,从而进一步提高复合光催化剂的催化性能㊂相对于纯g-C3N4和Ag基光催化剂,g-C3N4/Ag基二元复合光催化剂通过两组分的协同效应和界面作用,不仅能提高对可见光的吸收利用率,而且能有效抑制g-C3N4和Ag基材料中光生e-/h+对的重组,从而提高复合光催化剂的活性和稳定性㊂在g-C3N4/Ag基二元复合光催化材料中,以AgX(X=Cl,Br,I)/g-C3N4㊁Ag3PO4/g-C3N4㊁Ag2CO3/g-C3N4㊁Ag3VO4/g-C3N4㊁Ag2CrO4/g-C3N4㊁Ag2O/g-C3N4和Ag2MoO4/g-C3N4为典型代表㊂1.1㊀AgX(X=Cl,Br,I)/g-C3N4二元复合光催化剂AgX(X=Cl,Br,I)在杀菌㊁有机污染物降解和光催化水解产氢等方面展现出优异的性能㊂但AgX (X=Cl,Br,I)是一种光敏材料,在可见光下容易发生分解,形成Ag0,从而影响其催化活性及稳定性㊂将AgX(X=Cl,Br,I)与g-C3N4复合是提升AgX(X=Cl,Br,I)使用寿命㊁改善光催化性能最有效的方法之一㊂Li等[14]采用硬模板法制备出一种具有空心和多孔结构的高比表面积g-C3N4纳米球,并以其为载体,通过沉积-沉淀法得到AgBr/g-C3N4光催化材料㊂XRD分析显示AgBr的加入并没有改变g-C3N4的晶体结构,瞬态光电流试验表明AgBr/g-C3N4光电流密度高于g-C3N4,橙黄G(OG)染料经10min可见光照射后的降解率达到97%㊂Shi等[15]报道了利用沉淀回流法制备AgCl/g-C3N4光催化剂,研究了AgCl的量对催化剂结构及光催化降解草酸性能的影响,确定了最佳修饰量,分析了催化剂用量㊁草酸起始浓度㊁酸度和其他有机成分对光催化活性影响,通过自由基捕获试验揭示了光降解反应中起主要作用的活性物质为光生电子(e-)㊁羟基自由基(㊃OH)㊁超氧自由基(㊃O-2)和空穴(h+)㊂彭慧等[16]采用化学沉淀法制备具有不同含量AgI的AgI/g-C3N4光催化剂,SEM测试表明AgI纳米颗粒分布在层状结构g-C3N4薄片的表面,为催化反应提供了更多的活性位㊂该系列催化剂应用于光催化氧化降解孔雀石绿(melachite green,MG)的结果显示,AgI/g-C3N4(20%,质量分数,下同)的光催化性能最好,MG经2h可见光辐照后去除率达到99.8%㊂部分AgX(X=Cl,Br,I)/g-C3N4二元复合光催化剂的研究现状如表1所示㊂第10期柏林洋等:g-C 3N 4/Ag 基二元复合光催化剂降解环境污染物的研究进展3757㊀表1㊀AgX (X =Cl ,Br ,I )/g-C 3N 4二元复合光催化剂光降解环境污染物的研究现状Table 1㊀Research status of AgX (X =Cl ,Br ,I )/g-C 3N 4binary composite photocatalysts forphotodegradation of enviromental pollutantsPhotocatalytst Synthesis method TypePotential application Photocatalytic activity Reference AgBr /g-C 3N 4Sonication-assisted deposition-precipitation II-schemeDegradation of RhB,MB and MO 100%degradation for RhB,95%degradation for MB and 90%degradation for MO in 10min [17]AgCl /g-C 3N 4Precipitation Z-schemeDegradation of RhB and TC 96.1%degradation for RhB and 77.8%degradation for TC in 120min [18]AgCl /g-C 3N 4Solvothermal +in situ ultrasonic precipitation Z-scheme Degradation of RhB 92.2%degradation in 80min [19]AgBr /g-C 3N 4Deposition-precipitation II-schemeDegradation of MO 90%degradation in 30min [20]AgI /g-C 3N 4In-situ growth II-scheme Degradation of RhB 100%degradation in 60min [21]㊀㊀Note:MO-methyl orange,RhB-rhodamine B,TC-tetracycline hydrochloride,MB-methyl blue.1.2㊀Ag 3PO 4/g-C 3N 4二元复合光催化剂纳米Ag 3PO 4禁带宽度为2.5eV 左右,对可见光有很好的吸收作用,且光激发后具有很强的氧化性,在污染物降解和光解水制氢等领域有良好的应用前景[22]㊂但是,纳米Ag 3PO 4易团聚,光生载流子的快速重组使光催化活性大大降低,此外,Ag 3PO 4还易受光生e -的腐蚀,从而影响稳定性㊂Ag 3PO 4与g-C 3N 4复合可显著降低e -/h +对的重组,有效提高光催化性能㊂Wang 等[23]采用原位沉淀法获得Z-型异质结构g-C 3N 4/Ag 3PO 4复合光催化剂,并有效地提高了e -/h +对的分离效率㊂TEM 结果显示,Ag 3PO 4粒子被g-C 3N 4纳米片所覆盖,UV-DRS 结果表明,Ag 3PO 4的添加使g-C 3N 4吸收边发生红移,且吸收光强度显著增强,光降解实验结果显示,30%g-C 3N 4/Ag 3PO 4光催化剂在40min 内能去除约90%的RhB㊂胡俊俊等[24]利用了原位沉淀法合成了一系列Ag 3PO 4/g-C 3N 4复合光催化剂,研究了Ag 3PO 4和g-C 3N 4的物质的量比对催化剂在可见光下催化降解MB 性能的影响,发现在最优组分下,MB 经可见光辐照30min 后可以被完全降解㊂Mei 等[25]采用焙烧-沉淀法制备了一系列Ag 3PO 4/g-C 3N 4复合光催化剂,并用于可见光条件下降解双酚A(bisphenol A,BPA),发现Ag 3PO 4质量分数为25%时,光催化降解BPA 的性能最好,3h 能降解92.8%的BPA㊂潘良峰等[26]采用化学沉淀法制备出一种具有空心管状的Ag 3PO 4/g-C 3N 4光催化剂,SEM 结果表明,Ag 3PO 4颗粒均匀分布于空心管状结构g-C 3N 4的表面,两者形成一个较强异质结构,将其用于盐酸四环素(tetracycline hydrochloride,TC)光催化降解,80min 能降解98%的TC㊂Deonikar 等[27]研究了采用原位湿化学法合成催化剂过程中使用不同溶剂(去离子水㊁四氢呋喃和乙二醇)对Ag 3PO 4/g-C 3N 4的结构和光降解MB㊁RhB 及4-硝基苯酚性能的影响,发现不同溶剂对复合光催化剂的形貌有着重要影响,从而影响光催化性能,其中以四氢呋喃合成的复合光催化剂的催化降解性能最佳,这是由于g-C 3N 4纳米片均匀包裹在Ag 3PO 4的表面,从而促使两者界面形成较为密切的相互作用,有利于e -/h +对的分离㊂部分Ag 3PO 4/g-C 3N 4二元复合光催化剂的研究进展见表2㊂表2㊀Ag 3PO 4/g-C 3N 4二元复合光催化剂光降解环境污染物的研究现状Table 2㊀Research status of Ag 3PO 4/g-C 3N 4binary composite photocatalysts for photodegradation of environmental pollutantsPhotocatalyst Synthesis method Type Potential application Photocatalytic activity Reference g-C 3N 4/Ag 3PO 4In situ precipitation Z-scheme Degradation of BPA 100%degradation in 180min [28]g-C 3N 4/Ag 3PO 4Hydrothermal Z-schemeDecolorization of MB Almost 93.2%degradation in 25min [29]g-C 3N 4/Ag 3PO 4In situ prepcipitation II-scheme Reduction of Cr(VI)94.1%Cr(VI)removal efficiency in 120min [30]g-C 3N 4/Ag 3PO 4Chemical precipitation Z-scheme Degradation of RhB 90%degradation in 40min [31]g-C 3N 4/Ag 3PO 4In situ precipitation Z-scheme Degradation of levofloxacin 90.3%degradation in 30min [32]Ag 3PO 4/g-C 3N 4Chemical precipitation Z-schemeDegradation of gaseous toluene 87.52%removal in 100min [33]Ag 3PO 4/g-C 3N 4Calcination +precipitation Z-scheme Degradation of diclofenac (DCF)100%degradation in 12min [34]Ag 3PO 4/g-C 3N 4In situ deposition Z-scheme Degradation of RhB and phenol 99.4%degradation in 9min for RhB;97.3%degradation in 30min for phenol [35]3758㊀陶㊀瓷硅酸盐通报㊀㊀㊀㊀㊀㊀第42卷续表Photocatalyst Synthesis method Type Potential application Photocatalytic activity Reference Ag3PO4/g-C3N4In situ hydrothermal II-scheme Degradation of sulfapyridine(SP)94.1%degradation in120min[36] Ag3PO4/g-C3N4In situ growth Z-scheme Degradation of berberine100%degradation in15min[37] g-C3N4/Ag3PO4In situ deposition Z-scheme Degradation of ofloxacin71.9%degradation in10min[38] Ag3PO4/g-C3N4Co-precipitation Z-scheme Degradation of MO98%degradation in10min[39]g-C3N4/Ag3PO4Calcination+precipitation Z-scheme Degradation of MO,RhB and TC95%degradation for MO in30min;[40]96%degradation for RhB in15min;80%degradation for TC in30min1.3㊀Ag2CO3/g-C3N4二元复合光催化剂Ag4d轨道和O2p轨道杂化,形成Ag2CO3的价带(valence band,VB);Ag5s轨道和Ag4d轨道进行杂化,形成Ag2CO3导带(conduction band,CB),而CB中原子轨道杂化会降低Ag2CO3带隙能,从而提高光催化活性[41]㊂纳米Ag2CO3带隙能约为2.5eV,可见光响应性好,在可见光作用下表现出良好的光催化降解有机污染物特性[42-43]㊂然而,经长时间光照后,Ag2CO3晶粒中Ag+会被光生e-还原成Ag0,导致其光腐蚀,引起光催化性能下降[44]㊂Ag2CO3与g-C3N4耦合,能够有效地抑制光腐蚀,促进e-/h+对的分离,进而改善光催化性能㊂An等[45]通过构筑Z型核壳结构的Ag2CO3@g-C3N4材料来增强Ag2CO3和g-C3N4界面间的相互作用,从而有效防止光腐蚀发生,加速光生e-/h+对的分离,实现了催化剂在可见光辐照下高效降解MO㊂Yin等[46]通过水热法制备Ag2CO3/g-C3N4光催化剂,探讨了g-C3N4的含量㊁合成温度对催化剂结构和光降解草酸(oxalic acid,OA)性能的影响,获得最优条件下合成的催化剂能在45min光照时间内使OA去除率达到99.99%㊂Pan等[41]采用煅烧和化学沉淀两步法,制备了一系列Ag2CO3/g-C3N4光催化剂,TEM结果显示,Ag2CO3纳米粒子均匀分布在g-C3N4纳米片表面,且形貌规整㊁粒径均一,光催化性能测试结果表明,60% Ag2CO3/g-C3N4光催化活性最高,MO和MB分别经120和240min可见光光照后,其降解率分别为93.5%和62.8%㊂Xiu等[47]使用原位水热法构筑了Ag2CO3/g-C3N4光催化剂,光降解试验结果表明,MO经可见光辐照1h的去除率为87%㊂1.4㊀Ag3VO4/g-C3N4二元复合光催化剂纳米Ag3VO4带隙能约为2.2eV,可用于催化可见光降解环境污染物,是一种具有应用前景的新型半导体材料㊂然而,如何提高Ag3VO4光催化性能,仍然是学者研究的重点㊂构建Ag3VO4/g-C3N4异质结催化剂是提高Ag3VO4的催化性能的一种有效方法㊂该方法能够降低Ag3VO4光生载流子的复合率,拓宽可见光的吸收范围㊂Hind等[48]通过溶胶凝胶法制备出一种具有介孔结构的Ag3VO4/g-C3N4复合光催化剂,该复合催化剂经60min可见光照射能将Hg(II)全部还原,其光催化活性分别是Ag3VO4和g-C3N4的4.3倍和5.4倍,主要是由于异质结界面处各组分间紧密结合以及催化剂具有较高的比表面积和体积比,从而促进光生载流子的分离㊂蒋善庆等[49]利用化学沉淀法制备了系列Ag3VO4/g-C3N4催化剂,催化性能研究结果表明,Ag3VO4负载量为20%(质量分数)时,其光催化降解微囊藻毒素的效果最好,可见光辐照100min后降解率为85.43%,而g-C3N4在相同条件下的降解率仅为18.76%㊂1.5㊀Ag2CrO4/g-C3N4二元复合光催化剂纳米Ag2CrO4具有特殊的晶格和能带结构,其带隙能为1.8eV,可见光响应良好,是一种非常理想的可见光区半导体材料㊂然而,Ag2CrO4存在自身的电子结构和晶体的缺陷,导致其光催化效率性能较差,严重影响了实际应用[50-52]㊂将Ag2CrO4与g-C3N4复合形成异质结光催化剂是提高其光催化效率和稳定性的一种有效途径,因为Ag2CrO4在光照下产生的光生e-快速地迁移到g-C3N4表面,可避免光生e-在Ag2CrO4表面聚集而引起光腐蚀㊂Ren等[53]利用SiO2为硬模板,以氰胺为原料,合成出具有中空介孔结构的g-C3N4,再通过化学沉淀法制备了系列g-C3N4/Ag2CrO4光催化剂,并将其用于RhB和TC的可见光降解,研究发现g-C3N4/Ag2CrO4催化剂具有较高比表面积和丰富的孔道结构,在可见光辐射下表现出较高的光催化活性㊂Rajalakshmi等[54]利用水热方法合成了一系列Ag2CrO4/g-C3N4光催化剂,并将其用于对硝基苯酚的光催化降解,结果表明,Ag2CrO4质量分数为10%时,其降解率达到97%,高于单组分g-C3N4或Ag2CrO4,原因是与第10期柏林洋等:g-C 3N 4/Ag 基二元复合光催化剂降解环境污染物的研究进展3759㊀Ag 2CrO 4和g-C 3N 4界面间形成了S-型异质结,能提高e -/h +对的分离效率㊂1.6㊀Ag 2O /g-C 3N 4二元复合光催化剂纳米Ag 2O 是一种理想的可见光半导体材料,在受到光辐照后,其电子发生跃迁,CB 上光生e -能够将Ag 2O 晶粒中Ag +还原成Ag 0,而VB 上h +能够使Ag 2O 的晶格氧氧化为O 2,导致其结构不稳定㊂然而,纳米Ag 2O 在有机物污染物降解方面表现出良好的稳定性[55],这是因为Ag 2O 的表面会随着光化学反应的进行被一定数量的Ag 0纳米粒子所覆盖,而Ag 0纳米粒子作为光生e -陷阱,能够降低e -在Ag 2O 表面的富集,同时,由于光生h +具有较强的氧化性能力,既能实现对有机污染物的直接氧化,又能避免其对晶格氧的氧化,从而提高了纳米Ag 2O 光催化活性和稳定性㊂Liang 等[56]在常温下采用简易化学沉淀法制备了p-n 结Ag 2O /g-C 3N 4复合光催化剂,研究发现,起分散作用的g-C 3N 4为Ag 2O 纳米颗粒的生长提供了大量成核位点并限制了Ag 2O 纳米颗粒聚集,p-n 结的形成以及在光化学反应过程中生成的Ag 纳米粒子,加速了光生载流子的分离和迁移,拓宽了光的吸收范围,在可见光和红外光照下降解RhB 溶液过程中表现出良好的催化活性,其在可见光和红外光照下反应速率分别是g-C 3N 4的26倍和343倍㊂Jiang 等[57]通过液相法制备了一系列介孔结构的g-C 3N 4/Ag 2O 光催化剂,试验结果表明,Ag 2O 的添加显著提高了g-C 3N 4/Ag 2O 光催化剂的吸光性能和比表面积,因此对光催化性能的提升有促进作用,当Ag 2O 含量为50%时,光催化分解MB 的效果最好,经120min 可见光光照后,MB 的脱除率达到90.8%,高于g-C 3N 4和Ag 2O㊂Kadi 等[58]以Pluronic 31R 1表面活性剂为软模板,以MCM-41为硬模板,合成出具有多孔结构的Ag 2O /g-C 3N 4光催化剂,TEM 结果显示,球形Ag 2O 的纳米颗粒均匀地分布于g-C 3N 4的表面,催化性能评价表明0.9%Ag 2O /g-C 3N 4复合光催化剂光催化效果最佳,60min 能完全氧化降解环丙沙星,其降解效率分别是Ag 2O 和g-C 3N 4的4倍和10倍㊂1.7㊀Ag 2MoO 4/g-C 3N 4二元复合光催化剂Ag 2MoO 4具有良好的导电性㊁抗菌性㊁环保性,以及优良的光催化活性,在荧光材料㊁导电玻璃㊁杀菌剂和催化剂等方面有着广阔的应用前景[59]㊂但Ag 2MoO 4带隙大(3.1eV),仅能对紫外波段光进行响应,限制了其对太阳光的利用㊂当Ag 2MoO 4与g-C 3N 4进行耦合时,可以将其对太阳光的吸收范围由紫外拓展到可见光区,从而提高太阳光的利用率㊂Pandiri 等[60]通过水热合成的方法,制备出β-Ag 2MoO 4/g-C 3N 4异质结光催化剂,SEM 结果显示该催化剂中β-Ag 2MoO 4纳米颗粒均匀地分布在g-C 3N 4纳米片的表面,光催化性能测试结果表明在3h 的可见光照射下,其降解能力是β-Ag 2MoO 4和g-C 3N 4机械混合物的2.6倍,主要原因在于β-Ag 2MoO 4和g-C 3N 4两者界面间形成更为紧密的异质结,使得e -/h +对被快速分离㊂Wu 等[61]采用简单的原位沉淀方法成功构建了Ag 2MoO 4/g-C 3N 4光催化剂,并将其应用于MO㊁BPA 和阿昔洛韦的降解,结果表明该催化剂显示出良好的太阳光催化活性,这主要是因为Ag 2MoO 4和g-C 3N 4界面间存在着一定的协同效应,可有效地提高对太阳光的利用率,降低载流子的复合概率㊂2㊀g-C 3N 4/Ag 基二元复合光催化剂电荷转移机理模型研究g-C 3N 4/Ag 基二元复合光催化剂在可见光的辐照下,价带电子发生跃迁,产生e -/h +对㊂e -被催化剂表面吸附的O 2捕获产生㊃O -2,并进一步与水反应生成㊃OH,形成的三种活性自由基(h +㊁㊃O -2和㊃OH),实现水中有机污染物的高效降解(见图1)㊂而光催化反应机理与载流子的迁移机制密切相关㊂目前,g-C 3N 4/Ag 基二元复合光催化剂体系中主要存在三种不同的光生载流子的转移机制,分别为I 型㊁II 型和Z 型㊂图1㊀g-C 3N 4/Ag 基二元复合光催化剂降解有机污染物的光催化反应机理Fig.1㊀Photocatalytic reaction mechanism of g-C 3N 4/Ag-based binary composite photocatalyst for degradation of organic pollutants3760㊀陶㊀瓷硅酸盐通报㊀㊀㊀㊀㊀㊀第42卷2.1㊀I 型异质结载流子转移机理模型图2(a)为I 型异质结构中的光生e -/h +对转移示意图㊂半导体A 和半导体B 均对可见光有响应,其中,半导体A 的带隙较宽,半导体B 的带隙较窄,并且半导体B 的VB 和CB 均位于半导体A 之间,在可见光的照射下,e -发生跃迁,从CB 到VB,半导体A 的CB 上的e -和VB 上的h +分别向半导体B 的CB 和VB 转移,从而实现了e -/h +对的分离㊂以Ag 2O /g-C 3N 4复合催化剂为例[58],当Ag 2O 和g-C 3N 4相耦合时,因为g-C 3N 4的VB 具有更正的电势,h +被转移到Ag 2O 的VB 上,同时,光激发e -在g-C 3N 4的CB 上,其电势较负,e -便传输到Ag 2O 的CB 上,CB 上e -与O 2结合形成㊃O -2,并进一步与H +结合生成了㊃OH,而有机物污染物被Ag 2O 的价带上h +氧化分解生成CO 2和H 2O㊂2.2㊀II 型异质结载流子转移机理模型II 型异质结是一种能级交错带隙型结构,如图2(b)所示,其中半导体A 的CB 电位较负,在可见光照射下,e -从CB 上转移到半导体B 的CB 上,h +从半导体B 的VB 转移到半导体A 的VB 上,从而使e -/h +对得以分离㊂以Ag 3PO 4@g-C 3N 4为例[62],由于g-C 3N 4的CB 的电势较Ag 3PO 4低,光生e -从g-C 3N 4迁移到Ag 3PO 4的CB 上,而Ag 3PO 4的CB 电势较g-C 3N 4高,h +从Ag 3PO 4的VB 迁移到g-C 3N 4的VB 上,从而实现e -/h +对的分离,g-C 3N 4表面的h +可直接氧化降解MB,而Ag 3PO 4表面积聚的电子又会被氧捕获,产生H 2O 2,并进一步分解成㊃OH,从而加快MB 的降解㊂上述I 型和II 型结构CB 的氧化能力和VB 还原能力低于单一组分,造成复合半导体的氧化还原能力降低[63]㊂2.3㊀Z 型异质结载流子转移机理模型构建Z 型异质结光光催化剂使得e -和h +沿着特有的方向迁移,有效解决复合催化剂氧化还原能力降低问题[64]㊂Z 型异质结催化剂e -/h +对的迁移方向如图2(c)所示,e -从半导体B 的电势较高的CB 转移到半导体A 的电势较低的VB 进行复合,从而实现半导体A 的e -和半导体B 的h +发生分离㊂h +在半导体B 表面氧化性能更强,在半导体A 上e -具有较高还原特性,两者共同作用使环境污染物得以顺利降解㊂为了更好地解释Z 型异质结h +和e -迁移机理,以Ag 3VO 4/g-C 3N 4复合光催化剂为例[48],复合光催化剂经可见光激发后,Ag 3VO 4和g-C 3N 4都发生了e -跃迁,在Ag 3VO 4的CB 上e -与g-C 3N 4的VB 上h +进行复合时,e -对Ag 3VO 4的腐蚀作用被削弱,同时,也实现了g-C 3N 4的CB 上e -和Ag 3PO 4的价带上h +发生分离,g-C 3N 4的CB 上e -具有较强的还原性,将Hg 2+还原成Hg 0,而Ag 3PO 4的VB 上h +具有较强的氧化性,可将HOOH氧化生成CO 2和H 2O㊂图2㊀电子-空穴对转移机理示意图Fig.2㊀Schematic diagrams of electron-hole pairs transfer mechanism 3㊀结语和展望g-C 3N 4/Ag 基二元复合光催化剂因其较强的可见光响应和优异的光催化性能,在环境污染物的降解方面具有广阔的发展空间㊂近年来,国内外研究人员在理论研究㊁制备方法和光催化性能等多个领域取得了重要进展,为光催化理论的发展奠定了坚实的基础㊂然而,g-C 3N 4/Ag 基二元复合光催化剂在实际应用中还面临诸多问题,如制备工艺复杂㊁光腐蚀㊁光催化剂回收利用困难㊁光催化降解污染物的反应机理尚不明确等,第10期柏林洋等:g-C3N4/Ag基二元复合光催化剂降解环境污染物的研究进展3761㊀现有的光催化降解模型仍有较大的分歧,亟待深入研究㊂为了获得性能优良的g-C3N4/Ag基复合光催化剂,实现产业化应用,应进行以下几方面的研究:1)在g-C3N4/Ag基二元光催化剂的基础上,构建多元复合光催化剂,是进一步提升光生载流子分离效率的有效㊁可靠手段,也是当今和今后光催化剂的研究重点㊂2)对g-C3N4/Ag基二元光催化剂体系中e-/h+对的转移㊁分离和复合等过程进行系统研究,并阐明其光催化反应机制㊂3)针对当前合成的g-C3N4材料多为体相,存在着颗粒大㊁比表面积小㊁活性位少等缺陷,应通过对g-C3N4材料的形状㊁形貌及尺寸的调控,来实现Ag 基材料在g-C3N4材料表面的均匀分布,降低e-/h+对的重组概率,从而大幅度提高复合光催化剂的性能㊂4)Ag基材料的光腐蚀是导致光催化活性和稳定性下降的重要因素,探索一种更为有效的光腐蚀抑制机制,是将其推广应用的关键㊂5)当前合成的g-C3N4/Ag基二元复合光催化剂多为粉末状,存在着易团聚㊁难回收等问题,从而限制了其循环利用㊂因此,需要开展g-C3N4/Ag基二元复合光催化剂回收和再利用的研究,这将有利于社会效益和经济效益的提高㊂参考文献[1]㊀LIN Z S,DONG C C,MU W,et al.Degradation of Rhodamine B in the photocatalytic reactor containing TiO2nanotube arrays coupled withnanobubbles[J].Advanced Sensor and Energy Materials,2023,2(2):100054.[2]㊀DIAO Z H,JIN J C,ZOU M Y,et al.Simultaneous degradation of amoxicillin and norfloxacin by TiO2@nZVI composites coupling withpersulfate:synergistic effect,products and mechanism[J].Separation and Purification Technology,2021,278:119620.[3]㊀ZHAO S Y,CHEN C X,DING J,et al.One-pot hydrothermal fabrication of BiVO4/Fe3O4/rGO composite photocatalyst for the simulated solarlight-driven degradation of Rhodamine B[J].Frontiers of Environmental Science&Engineering,2021,16(3):1-16.[4]㊀JUABRUM S,CHANKHANITTHA T,NANAN S.Hydrothermally grown SDS-capped ZnO photocatalyst for degradation of RR141azo dye[J].Materials Letters,2019,245:1-5.[5]㊀SUN Z X,WANG H Q,WU Z B,et al.g-C3N4based composite photocatalysts for photocatalytic CO2reduction[J].Catalysis Today,2018,300:160-172.[6]㊀LIN L,SU Z Y,LI Y,et parative performance and mechanism of bacterial inactivation induced by metal-free modified g-C3N4undervisible light:Escherichia coli versus Staphylococcus aureus[J].Chemosphere,2021,265:129060.[7]㊀DANG X M,WU S,ZHANG H G,et al.Simultaneous heteroatom doping and microstructure construction by solid thermal melting method forenhancing photoelectrochemical property of g-C3N4electrodes[J].Separation and Purification Technology,2022,282:120005. [8]㊀VAN KHIEN N,HUU H T,THI V N N,et al.Facile construction of S-scheme SnO2/g-C3N4photocatalyst for improved photoactivity[J].Chemosphere,2022,289:133120.[9]㊀LINH P H,DO CHUNG P,VAN KHIEN N,et al.A simple approach for controlling the morphology of g-C3N4nanosheets with enhancedphotocatalytic properties[J].Diamond and Related Materials,2021,111:108214.[10]㊀XIE M,TANG J C,KONG L S,et al.Cobalt doped g-C3N4activation of peroxymonosulfate for monochlorophenols degradation[J].ChemicalEngineering Journal,2019,360:1213-1222.[11]㊀ZHEN X L,FAN C Z,TANG L,et al.Advancing charge carriers separation and transformation by nitrogen self-doped hollow nanotubes g-C3N4for enhancing photocatalytic degradation of organic pollutants[J].Chemosphere,2023,312:137145.[12]㊀AL-HAJJI L A,ISMAIL A A,FAYCAL A M,et al.Construction of mesoporous g-C3N4/TiO2nanocrystals with enhanced photonic efficiency[J].Ceramics International,2019,45(1):1265-1272.[13]㊀CUI P P,HU Y,ZHENG M M,et al.Enhancement of visible-light photocatalytic activities of BiVO4coupled with g-C3N4prepared usingdifferent precursors[J].Environmental Science and Pollution Research,2018,25(32):32466-32477.[14]㊀LI X W,CHEN D Y,LI N J,et al.AgBr-loaded hollow porous carbon nitride with ultrahigh activity as visible light photocatalysts for waterremediation[J].Applied Catalysis B:Environmental,2018,229:155-162.[15]㊀SHI H L,HE R,SUN L,et al.Band gap tuning of g-C3N4via decoration with AgCl to expedite the photocatalytic degradation and mineralizationof oxalic acid[J].Journal of Environmental Sciences,2019,84:1-12.[16]㊀彭㊀慧,刘成琪,汪楚乔,等.AgI/g-C3N4复合材料制备及其降解孔雀石绿染料性能[J].环境工程,2019,37(4):93-97.PENG H,LIU C Q,WANG C Q,et al.Preparation of AgI/g-C3N4composites and their degradation performance of malachite green dyes[J].Environmental Engineering,2019,37(4):93-97(in Chinese).[17]㊀LIANG W,TANG G,ZHANG H,et al.Core-shell structured AgBr incorporated g-C3N4nanocomposites with enhanced photocatalytic activityand stability[J].Materials Technology,2017,32(11):675-685.[18]㊀LI Y B,HU Y R,LIU Z,et al.Construction of self-activating Z-scheme g-C3N4/AgCl heterojunctions for enhanced photocatalytic property[J].Journal of Physics and Chemistry of Solids,2023,172:111055.3762㊀陶㊀瓷硅酸盐通报㊀㊀㊀㊀㊀㊀第42卷[19]㊀XIE J S,WU C Y,XU Z Z,et al.Novel AgCl/g-C3N4heterostructure nanotube:ultrasonic synthesis,characterization,and photocatalyticactivity[J].Materials Letters,2019,234:179-182.[20]㊀YANG J,ZHANG X,LONG J,et al.Synthesis and photocatalytic mechanism of visible-light-driven AgBr/g-C3N4composite[J].Journal ofMaterials Science:Materials in Electronics,2021,32:6158-6167.[21]㊀HUANG H,LI Y X,WANG H L,et al.In situ fabrication of ultrathin-g-C3N4/AgI heterojunctions with improved catalytic performance forphotodegrading rhodamine B solution[J].Applied Surface Science,2021,538:148132.[22]㊀GUO C S,CHEN M,WU L L,et al.Nanocomposites of Ag3PO4and phosphorus-doped graphitic carbon nitride for ketamine removal[J].ACSApplied Nano Materials,2019,2(5):2817-2829.[23]㊀WANG H R,LEI Z,LI L,et al.Holey g-C3N4nanosheet wrapped Ag3PO4photocatalyst and its visible-light photocatalytic performance[J].Solar Energy,2019,191:70-77.[24]㊀胡俊俊,丁同悦,陈奕桦,等.Ag3PO4/g-C3N4复合材料的制备及其光催化性能[J].精细化工,2021,38(3):483-488.HU J J,DING T Y,CHEN Y H,et al.Preparation and photocatalytic application of Ag3PO4/g-C3N4composites[J].Fine Chemicals,2021,38(3):483-488(in Chinese).[25]㊀MEI J,ZHANG D P,LI N,et al.The synthesis of Ag3PO4/g-C3N4nanocomposites and the application in the photocatalytic degradation ofbisphenol A under visible light irradiation[J].Journal of Alloys and Compounds,2018,749:715-723.[26]㊀潘良峰,阎㊀鑫,王超莉,等.中空管状g-C3N4/Ag3PO4复合催化剂的制备及其可见光催化性能[J].无机化学学报,2022,38(4):695-704.PAN L F,YAN X,WANG C L,et al.Preparation and visible light photocatalytic activity of hollow tubular g-C3N4/Ag3PO4composite catalyst[J].Chinese Journal of Inorganic Chemistry,2022,38(4):695-704(in Chinese).[27]㊀DEONIKAR V G,KOTESHWARA R K,CHUNG W J,et al.Facile synthesis of Ag3PO4/g-C3N4composites in various solvent systems withtuned morphologies and their efficient photocatalytic activity for multi-dye degradation[J].Journal of Photochemistry and Photobiology A: Chemistry,2019,368:168-181.[28]㊀DU J G,XU Z,LI H,et al.Ag3PO4/g-C3N4Z-scheme composites with enhanced visible-light-driven disinfection and organic pollutantsdegradation:uncovering the mechanism[J].Applied Surface Science,2021,541:148487.[29]㊀NAGAJYOTHI P C,SREEKANTH T V M,RAMARAGHAVULU R,et al.Photocatalytic dye degradation and hydrogen production activity ofAg3PO4/g-C3N4nanocatalyst[J].Journal of Materials Science:Materials in Electronics,2019,30(16):14890-14901.[30]㊀AN D S,ZENG H Y,XIAO G F,et al.Cr(VI)reduction over Ag3PO4/g-C3N4composite with p-n heterostructure under visible-light irradiation[J].Journal of the Taiwan Institute of Chemical Engineers,2020,117:133-143.[31]㊀YAN X,WANG Y Y,KANG B B,et al.Preparation and characterization of tubelike g-C3N4/Ag3PO4heterojunction with enhanced visible-lightphotocatalytic activity[J].Crystals,2021,11(11):1373.[32]㊀高闯闯,刘海成,孟无霜,等.Ag3PO4/g-C3N4复合光催化剂的制备及其可见光催化性能[J].环境科学,2021,42(5):2343-2352.GAO C C,LIU H C,MENG W S,et al.Preparation of Ag3PO4/g-C3N4composite photocatalysts and their visible light photocatalytic performance[J].Environmental Science,2021,42(5):2343-2352(in Chinese).[33]㊀CHENG R,WEN J Y,XIA J C,et al.Photo-catalytic oxidation of gaseous toluene by Z-scheme Ag3PO4-g-C3N4composites under visible light:removal performance and mechanisms[J].Catalysis Today,2022,388/389:26-35.[34]㊀ZHANG W,ZHOU L,SHI J,et al.Synthesis of Ag3PO4/g-C3N4composite with enhanced photocatalytic performance for the photodegradation ofdiclofenac under visible light irradiation[J].Catalysts,2018,8(2):45.[35]㊀ZHANG M X,DU H X,JI J,et al.Highly efficient Ag3PO4/g-C3N4Z-scheme photocatalyst for its enhanced photocatalytic performance indegradation of rhodamine B and phenol[J].Molecules,2021,26(7):2062.[36]㊀LI K,CHEN M M,CHEN L,et al.In-situ hydrothermal synthesis of Ag3PO4/g-C3N4nanocomposites and their photocatalytic decomposition ofsulfapyridine under visible light[J].Processes,2023,11(2):375.[37]㊀汲㊀畅,王国胜.Ag3PO4/g-C3N4异质结催化剂可见光降解黄连素[J].无机盐工业,2022,54(4):175-180.JI C,WANG G S.Degradation of berberine by visible light over Ag3PO4/g-C3N4heterojunction catalyst[J].Inorganic Chemicals Industry, 2022,54(4):175-180(in Chinese).[38]㊀CHEN R H,DING S Y,FU N,et al.Preparation of a g-C3N4/Ag3PO4composite Z-type photocatalyst and photocatalytic degradation ofOfloxacin:degradation performance,reaction mechanism,degradation pathway and toxicity evaluation[J].Journal of Environmental Chemical Engineering,2023,11(2):109440.[39]㊀HAYATI M,ABDUL H A,ZUL A M H,et al.In-depth investigation on the photostability and charge separation mechanism of Ag3PO4/g-C3N4photocatalyst towards very low visible light intensity[J].Journal of Molecular Liquids,2023,376:121494.[40]㊀DING M,ZHOU J J,YANG H C,et al.Synthesis of Z-scheme g-C3N4nanosheets/Ag3PO4photocatalysts with enhanced visible-lightphotocatalytic performance for the degradation of tetracycline and dye[J].Chinese Chemical Letters,2020,31(1):71-76.[41]㊀PAN S G,JIA B Q,FU Y S.Ag2CO3nanoparticles decorated g-C3N4as a high-efficiency catalyst for photocatalytic degradation of organiccontaminants[J].Journal of Materials Science:Materials in Electronics,2021,32(11):14464-14476.。

Nature子刊：提高高强度铝合金抗疲劳能力（翻译）

Nature子刊：提高高强度铝合金抗疲劳能力（翻译）摘要众所周知，高强度铝合金在飞机、火车、卡车和汽车的使用中抗疲劳性能表现很差，工程师们在设计铝合金制造轻量化运输结构时往往受此影响。

本文提出了一个新的概念：微观结构设计提高疲劳强度。

微结构的设计是为了利用在初始疲劳循环中传递的机械能，以动态修复微观结构中固有的弱点，使高强度铝合金的疲劳寿命提高了25倍，疲劳强度提高到拉伸强度的1/2左右（与钢相当），该方法包含了静态和动态载荷之间的差异，并代表了一种疲劳微观结构设计的概念变化。

引言铝合金是如今工程中使用量第二大合金材料，其密度仅为钢的1/3，重量较轻，无磁性，且具有优异的耐腐蚀性。

沉淀强化型铝合金由于其特定的机械性能（性能/密度），制成的部件在轻量化的应用中显示出巨大的竞争优势，例如在飞机、火车、卡车和汽车等交通行业。

正由于运输业强调轻量化以减少燃料排放，导致铝合金在这些重要应用中的使用不断增加[1、2、3]。

运输构件受交变应力的影响，因此材料必须承受的应力在本质上是循环的,这种载荷便导致疲劳[4,5,6,7,8,9]和材料抗疲劳失效的能力在这些应用中至关重要,据统计，80%的工程合金失效是由于疲劳[5,8]。

一种合金能承受较长时间（约107次循环）而不发生破坏的循环应力称为疲劳强度，它总是低于单一载荷下导致失效的拉应力。

在钢材中，疲劳强度（动态特性）和抗拉强度（静态特性）密切相关：疲劳强度/抗拉强度≈1/2（如图1）[10]，这便强调了当需要提高疲劳强度时所采取的一种方式——选择具有较高拉伸强度的材料。

然而，高强度铝合金的疲劳性能相对较差，这是铝合金的致命弱点之一。

图1显示了三种最常见的沉淀强化铝合金的疲劳和抗拉强度相关性：AA2024（Al-Cu-Mg）、AA6061（Al-Mg-Si）和AA7050（Al-Zn-Mg-（Cu））。

铝合金的疲劳强度约为其抗拉强度的1/3。

在在疲劳是必须要求性能的应用中，使用高强度铝合金时，工程师被迫围绕疲劳性能进行设计。

Co-Al2O3_高效催化CO2_氧化乙苯脱氢制苯乙烯

DOI: 10.19906/ki.JFCT.2023039Co-Al 2O 3高效催化CO 2氧化乙苯脱氢制苯乙烯司智伟1,#，丹少鹏1,#，陈树伟1,* ，潘大海1，王英雄1，闫晓亮2，李瑞丰2（1. 太原理工大学化学学院, 山西太原 030024；2. 太原理工大学化学工程与技术学院, 山西太原 030024）摘　要：采用溶胶-凝胶法制备了不同Co 含量的n Co-Al 2O 3催化剂(n = 2%、5%、10%、15%、20%)，研究了Co 含量对催化剂结构和CO 2氧化乙苯脱氢性能的影响。

结果发现，n Co-Al 2O 3催化剂上孤立的Co 2 +离子与催化活性具有良好的对应关系，表明孤立的四面体Co 2 +物种是其活性位点。

Co-Al 2O 3催化剂上的Co 物种结构和催化性能与Co 含量相关。

Co 含量较低（≤10%）时，催化剂上优先形成孤立的四面体Co 2 + 物种；随着Co 含量的增加，孤立的Co 2 +位点增加，催化剂活性随之提高。

Co 含量较高（>10%）时，催化剂上形成Co 3O 4晶体颗粒，导致孤立的Co 2 +位点减少，催化剂活性降低。

10Co-Al 2O 3表现出最佳催化性能，550 ℃下乙苯转化率达64.4%，苯乙烯选择性为99.3%，反应30 h 后，催化剂仍无明显失活，表明孤立的Co 2 +活性位点具有良好的结构稳定性和优异的抗积炭性能。

关键词：Co 基催化剂；乙苯；氧化脱氢；二氧化碳；苯乙烯中图分类号： O643.3 文献标识码： AHighly efficient Co-Al 2O 3 catalysts for oxidative dehydrogenation ofethylbenzene to styrene with CO 2SI Zhi-wei 1,#，DAN Shao-peng 1,#，CHEN Shu-wei 1,*，PAN Da-hai 1，WANG Ying-xiong 1，YAN Xiao-liang 2 ，LI Rui-feng2（1. College of Chemistry , Taiyuan University of Technology , Taiyuan 030024, China ；2. College of Chemical Engineering and Technology , Taiyuan University of Technology , Taiyuan 030024, China ）Abstract: n Co-Al 2O 3 catalysts with different Co contents (n =2%, 5%, 10%, 15%, 20%) were prepared by a sol-gel approach. The effect of Co content on the n Co-Al 2O 3 catalyst structure and performance in the oxidativedehydrogenation of ethylbenzene to styrene by CO 2 was investigated. The results showed that the isolated Co 2 +ionson the n Co-Al 2O 3 catalysts had a positive influence on the catalytic activity, where the isolated tetrahedral Co 2 +species were considered as the active sites. Co contents on the Co-Al 2O 3 catalyst greatly affected the structure of Cospecies and the catalytic performance. The isolated tetrahedral Co 2 +species are preferentially generated on the resultant n Co-Al 2O 3 catalyst when the content of Co (n ) is less than 10%; as a result, an increase of Co content hereleads to the formation of more isolated Co 2 +sites and then improves the catalytic activity of n Co-Al 2O 3 in the dehydrogenation of ethylbenzene. When Co content exceeded 10%, crystalline Co 3O 4 particles were obtained on theformed catalyst, which resulted in the decline of the isolated Co 2 +sites and catalytic activity. Among various n Co-Al 2O 3 catalysts, 10Co-Al 2O 3 exhibited the best catalytic performance, with 64.4% conversion rate for ethylbenzene and 99.3% selectivity for styrene at 550 ℃. This catalyst remained stable without obvious deactivation for 30 h ofreaction, which suggests that the isolated Co 2 +species as active sites presented excellent structural stability and excellent anti-coke deposition.Key words: Co-based catalyst ；ethylbenzene ；oxidative dehydrogenation ；CO 2；styrene苯乙烯（ST ）是仅次于聚乙烯、聚氯乙烯和环氧乙烷的第四大乙烯衍生产品，广泛用于生产树脂、塑料和合成橡胶等。

地面用晶体硅光伏组件设计鉴定和定型英文

地面用晶体硅光伏组件设计鉴定和定型英文Design and Identification of Ground-mounted Crystalline Silicon Photovoltaic Modules Abstract:Ground-mounted photovoltaic (PV) systems play a crucial role in the renewable energy industry. The design and identification of the PV modules used in these systems are crucial for their performance and efficiency. This paper presents an overview of the design and identification process, specifically focusing on crystalline silicon PV modules.1. IntroductionGround-mounted PV systems are widely adopted due to their higher power output and easy accessibility for maintenance. The overall efficiency of these systems heavily relies on the quality and design features of PV modules. The design and identification process involves analyzing various factors such as module efficiency, power tolerance, temperature coefficient, and environmental durability.2. Design considerations2.1 Module efficiencyEfficiency is a key performance indicator for PV modules. A higher efficiency module converts more sunlight into electricity, resulting in increased energy production. During the design process, the module efficiency should be considered to maximize the energy output of the system.2.2 Power tolerancePower tolerance refers to the range in which the actual power output of the module can deviate from its rated power output. Designing PV modules with tight power tolerances ensures consistent performance and energy production.2.3 Temperature coefficientThe temperature coefficient of a PV module indicates its sensitivity to changes in temperature. A low temperature coefficient allows the system to perform optimally even in high-temperature environments.2.4 Environmental durabilityGround-mounted PV modules are exposed to various environmental factors such as wind, rain, and snow. The design should ensure that the modules are durable and can withstand these elements, preventing damage and ensuring long-term performance.3. Identification process3.1 Standard compliancePV modules must comply with international standards such as IEC 61215 and IEC 61730 to ensure quality and performance. The modules are subjected to rigorous testing and evaluation before certification is granted.3.2 Electrical performance testingElectrical performance testing includes measuring the open-circuit voltage, short-circuit current, maximum power voltage, and maximum power current. These parameters provide important insights into the module's electrical characteristics.3.3 Thermal imagingThermal imaging is used to identify any hotspots on the PV modules which can indicate potential defects or malfunctioning cells. Hotspots can lead to efficiency losses and should be identified and addressed during the design phase.3.4 Outdoor performance evaluationOutdoor performance evaluation measures the actual energy output of the modules under real-world conditions. This evaluation provides valuable data to validate the module's performance and efficiency.4. ConclusionThe design and identification of ground-mounted crystalline silicon PV modules require careful consideration of various factors such as efficiency, power tolerance, temperature coefficient, and environmental durability. Compliance with international standards, electrical performance testing, thermal imaging, and outdoor performance evaluation are important steps in the identification process. By following these guidelines, designers can ensure the optimal performance and long-term reliability of ground-mounted PV systems.。

OSRAM OSTAR Observation应用注意事项说明书

April 8, 2011page 1 of 10OSRAM OSTAR Observation Application NoteSummaryThis application note provides an overview of the general handling and functionality of the OSRAM OSTAR Observation. The im-portant optical and electrical characteristics are described and the thermal requirements for stable operation of the IR LED light source are addressed.In addition, the procedure for dimensioning an appropriate heat sink is illustrated by means of an example.Applications of the IR light source OSRAM OSTAR ObservationThere are various possibilities where our customers are using the OSRAM OSTAR Observation as IR light source:- Infrared illumination for cameras - General monitoring systems - IR data transfer- Driver assistance systems.Due to its compact and flat design together with its high light density, the OSRAM OSTAR Observation can be easily inte-grated in various applications. This opens up new application areas that were off limits to conventional IR devices.Construction of the OSRAM OSTAR ObservationDuring design of the OSRAM OSTAR Ob-servation, special attention was given to the thermal optimization of the module.The module core is formed from ten highly efficient semiconductor chips mounted on ceramic. For optimal heat transfer, the ce-ramic is directly mounted to the aluminum of the insulated metal core circuit board (base plate). This results in optimal heat dissipa-tion and additionally provides a sufficiently large area for a good thermal connection to the system heat sink where the OSRAM OSTAR module has to be attached to.With this construction, the light source itself exhibits a very low thermal resistance (R thJB ) between junction and base plate of 2.8 K/W.The frame surrounding the chips is available in black and white colour to enable a choice depending on the desired application.The black frame minimizes scattered light, which is important in imaging systems, whereas the white frame optimizes the total optical output power.Figure 1: Two frame colours are available for the OSRAM OSTAR Observation.April 8, 2011page 2 of 10Equipped with an ESD protection diode, the OSRAM OSTAR Observation possesses ESD protection up to 2 kV according to JESD22-A114-B.A thermistor (NTC EPCOS 8502) mounted to the base plate serves as a sensor for de-termining the temperature of the metal core board. The NTC temperature provides a good approximation of the average tempera-ture of the underside of the aluminum base plate. From this the junction temperature can be estimated (using R thJB ) and thus con-trolled.As a light source, semiconductors of the latest highly efficient thin film technology based on AlGaAs are employed. This pro-vides a nearly pure surface emitter with Lambertian radiation characteristics.All semiconductor chips are wired in series to achieve a constant intensity for all emit-ting surfaces.Tips for handling the OSRAM OSTAR ObservationIn order to protect the semiconductor chips from environmental influences such as mois-ture, they are encapsulated using a clear silicone.In addition, the silicone encapsulant allows an operation at a junction temperature of 145°C.Since this encapsulant is very elastic and soft, mechanical damage to the silicone should be minimized or avoided if at all pos-sible during processing (see also the appli-cation note "Handling of Silicone Resin LEDs“).This also applies to the black silicone en-capsulant for the connection contacts. Ex-cessive force on the cover can lead to spon-taneous failure of the light source (damageto the contacts).Figure 2: Areas of the silicone encapsu-lant of the OSRAM OSTAR Observation (shown in red hatch marks), which must not be damaged.In Figure 2, the corresponding locations are shown in red hatch marks.To prevent damaging or puncturing the en-capsulant the use of all types of sharp ob-jects should be avoided.Furthermore, it should be assured that the light source is provided with adequate cool-ing (see design example below) during op-eration. Even at low currents, prolonged operation without cooling can lead to over-heating, damage or even failure of the mod-ule.Electrical connection of the OS-RAM OSTAR ObservationFor easy electrical connection, the OSRAM OSTAR Observation is equipped with a 4-pin socket:Pin Assignment: Pin 1: Anode Pin 2: Thermistor Pin 3: Thermistor Pin 4: CathodeAs a mating plug, the SMD plug from ERNI (SMD214025.4-pins) is recommended.April 8, 2011page 3 of 10Mounting the OSRAM OSTAR Ob-servationSeveral mounting methods can be used for attaching the IR light source.When selecting an appropriate mounting method, make sure that a good heat transfer is provided between the OSRAM OSTAR Observation and the heat sink and that this is also guaranteed during operation.An insufficient or incorrect mounting can lead to thermal or mechanical problems dur-ing assembly.Generally, screws should be used for mount-ing the OSRAM OSTAR Observation.When mounting the module with M2 screws, a torque of 0.2 - 0.3 Nm should be used. In order to achieve a good thermal connection, the contact pressure should typically be in the range of 0.35 MPa.In addition to mounting with screws, the OSRAM OSTAR Observation can also be attached by means of gluing or clamping. When mounting with glue, care should be taken that the glue is both adhesive and thermally stable, and possesses a good thermal conductivity.When mounting a component to a heat sink, it should generally be kept in mind that the two solid surfaces must be brought into physical contact.Technical surfaces are never really flat or smooth, however, but have a certain rough-ness due to microscopic edges and depres-sions. When two such surfaces are joined together, contact occurs only at the surface peaks. The depressions remain separated and form air-filled cavities (Figure 3).DescriptionMaterial Advantages DisadvantagesThermally conductive pasteTypically silicone based, with heat conductiveparticlesThermally conductive compoundsImproved thermallyconductive paste – rub-bery film after curingThinnest connection with minimal pressureHigh thermal conductiv-ity No delaminationMaterial discharge at the edgesDanger of contamina-tion during mass pro-ductionPaste can escape and "creep" over timeConnections require curing process Phase Change Materi-als (PCM)Material of polyester or acrylic with lower glass transition temperature, filled with thermally con-ductive particlesEasy handling and mountingNo delaminationNo curingContact pressure re-quiredHeat pretreatment re-quiredThermally conductive elastomersSilicone plastic washer pads- filled with thermally conductive particles - often strengthened with glass fibers or di-electric filmsThermally conductive tapeDouble sided tape filled with particles for uniform thermal and adhesive propertiesNo leakage of materialCuring not requiredProblem with delamina-tionModerate thermal con-ductivityContact pressure re-quiredTable 1: Thermal Interface MaterialsApril 8, 2011page 4 of 10Figure 3: Heat flow with and without heat conductive material.Since air is a poor conductor of heat, these cavities should be filled with a thermally conductive material in order to significantly reduce the thermal resistance and improve the heat flow between the two adjacent sur-faces.Without an appropriate, optimally effective interface, only a limited amount of heat ex-change occurs between the two surfaces, eventually leading to overheating of the light source.To improve the heat transfer capability and reduce the thermal contact resistance, sev-eral materials are suitable.Thermally conductive pastes and com-pounds possess the lowest transfer resis-tance, but require a certain amount of care in handling.Elastomers and foils/bands are easy to use. With pretreated surfaces and appropriate contact pressure, a good thermal transfer can be realized.Table 1 shows an overview of the most commonly used thermally conductive mate-rials along with their most important advan-tages and disadvantages.Optical characteristics of the OS-RAM OSTAR ObservationWhen characterizing IR LEDs, the intensity is usually specified with two parameters - the total radiant flux Φe (units of mW) and the radiant intensity I e (units of mW/sr).The total radiant flux Φe of an LED describes the total radiated light power independent of direction. For the OSRAM OSTAR Observa-tion, this is shown in Figure 4, in relation to forward current.In contrast, the radiant intensity expresses the radiated power within a fixed solid angle (e.g. 0.01 sr ≙ ±3.2°) in the primary direction of radiation (optical axis).Figure 4: Relative total radiant flux in re-lation to forward current I F .The radiation characteristics (in the far field ) show the distribution of intensity dependent on angle and are shown for the OSRAM OSTAR Observation in Figure 5. This repre-sents a good approximation of a Lambertian source with a radiation angle of ±60°.In general, the brightness can be influenced with the help of appropriate secondary op-tics. That is, with the use of focusing optics, the light output within a particular angle can be significantly increased.April 8, 2011page 5 of 10Figure 5: Radiation characteristics with-out optics.The user should refrain from attempting to mount the primary optics to the silicone en-capsulant. This can lead to damage to the chip and especially to the bonding wires, thereby voiding the warranty provided by OSRAM.In the near field (at different operating cur-rents), the OSRAM OSTAR Observation exhibits the radiance images shown in Fig-ure 6.Figure 6: Radiance images in the near field at very low power (above) and at higher power (below).An especially homogeneous radiance is achieved through the black frame of the module - a particular advantage when using imaging optics.Optical safety regulationsDepending on the mode of operation, the OSRAM OSTAR Observation emits highly concentrated, invisible infrared radiation, which can be dangerous for the human eye. Products which contain these components must be handled according to the guidelines specified in IEC Standard 60825-1 and IEC 62471 "Photobiological Safety of Lamps and Lamp Systems“. Please see “Applica-tion Note Eye Safety” for more details.At high currents, one should always avoid looking at the optical path through a focus-ing lens, since the limits imposed by Laser Class 1M can be exceeded.Electrical characteristics and op-eration of the OSRAM OSTAR Ob-servationIn addition to optimized optical behavior, the new thin film AlGaAs technology also exhib-its improved electrical characteristics, when compared to traditional standard chip tech-nologies. These improvements lead to a significantly reduced forward voltage. It also enables higher forward currents for a given junction temperature.A typical current-voltage characteristic is shown in Figure 7.Care should be taken to observe the limiting conditions specified in the data sheet and at higher power, sufficient cooling should be provided.The OSRAM OSTAR Observation consists of a current-driven component, in which small voltage fluctuations at the input can lead to significant changes in current for theApril 8, 2011page 6 of 10device and thus to changes in the emitted output power. When selecting or developing suitable driver circuitry, it is therefore rec-ommended that appropriate current stabili-zation should also be provided. To find a suitable component for this purpose please see the manufacturer homepages linked on .Figure 7: Current-Voltage characteristic of the OSRAM OSTAR Observation.The efficiency of the OSRAM OSTAR Ob-servation module which results from the total radiated light power Φe and the electrical power P = V f x I f , is plotted in Figure 8. It is optimal at around 100 mA and de-creases at lower and higher currents.This is especially true for pulse operation at I f >100 mA, since the average optical power does not remain constant when the current is doubled and the duty cycle is halved.Figure 8: Efficiency in relation to forward current I f ; T B = 25°C, t pulse = 100µs.Thermal ConsiderationsIn order to achieve reliability and optimal performance for IR light sources such as the OSRAM OSTAR Observation, appropriate thermal management is necessary.Basically, there are two principle limitations for the maximum allowable temperature. First of all, for the OSRAM OSTAR Observa-tion, the maximum allowable base plate temperature T B of 125°C must not be ex-ceeded. Secondly, the maximum junction temperature is specified to be 145°C. Since these temperatures are dependent on the operating current and mode of operation (constant current or pulsed mode), the maximum allowable currents listed in the data sheet specify a T B of up to 125°C for DC operation. Thus, for example, the maxi-mum allowable constant current is 1 A for a base plate temperature T B = 85°C and is 650 mA at 110°C. The permissible pulse handling diagram shows the maximum cur-rent allowed for various pulse conditions with given pulse length t p and duty cycle D.April 8, 2011page 7 of 10Exceeding the maximum junction tempera-ture of 145°C can lead to irreversible dam-age to the LED and to spontaneous failure of the device.Due to underlying physical inter-dependencies associated with the function-ing of light emitting diodes, a change in the junction temperature T J - within the allowable temperature range - has an effect on several LED parameters.As a result, the forward voltage, radiant flux, wavelength and lifetime of LEDs are influ-enced by the junction temperature.Influence on forward voltage V f and optical power ΦeFor LEDs, an increase in junction tempera-ture leads to both a reduction of forward voltage V F (Figure 9), and a decrease in optical power Φe (Figure 10). The resulting changes are reversible. That is, the original default values return when the temperature change is reversed.For the application, this means that the lower the temperature of the semiconductor, the higher the light output will be.Influence on reliability and lifetimeIn general, with respect to aging, reliability and performance, continually driving the LEDs at their maximum allowable junction temperature is not recommended, since with an increase in temperature, a reduction in lifetime can be observed.Figure 9: Typical forward voltage in rela-tion to base plate temperature T B (I f = 1 A, t p = 10 ms).Figure 10: Relative optical power in rela-tion to base plate temperature for various pulsed currents (t p = 10 ms).April 8, 2011page 8 of 10Determination of the module tem-perature with the integrated NTCA good approximation of the base plate temperature TB can be determined from the measured resistance of the NTC and the curve given in the reference table (Fig-ure 12).Depending on the operating conditions, the corresponding junction temperature will be ΔT = R thJB x P D (P D = electrical power dissi-pation) higher. With appropriate feedback circuitry, T B and thus the junction tempera-ture can be regulated.Figure 11: Cross section of the OSRAM OSTAR Observation.Design ExampleIn the following example, the thermal re-quirements of the heat sink for the OSRAM OSTAR Observation are examined. In Fig-ure 13, an equivalent circuit for the different thermal resistances of the module is shown. Additional information is contained in the application note "Thermal Management of OSTAR-Projection Light Source".As a starting point for the thermal evaluation, an OSRAM OSTAR Observation module (10 Chips) is driven at an operating current of I f = 1000 mA and a maximum ambient tem-perature of T A = 50°C .From the given data and information from the data sheet, the requirements for the necessary cooling can be found by means ofthe following formula:Figure 12: Typical thermistor characteris-tics for the OSRAM OSTAR Observation (NTC EPCOS 8502).Where][][][][,)()(A I V V W P T T T K T f f Module D Safety mbient A unction J ⋅≈Δ−−=ΔWithT J(unction) = Max. Junction temperature (from data sheet: T J = 145°C)T B(aseplate) = Base plate temperatureT A(mbient) = Ambient temperature (T A = 50°C)ΔT Safety = Safety temperature range (typ.10 – 20K)V f = Forward voltage (from data sheet: V f = 15.5V)I f = Forward current (I f = 1A) Æ typ. P D, Module = 15.5 WApril 8, 2011page 9 of 10ΔT = Temperature change due to P D,ModuleR th,Interface = Thermal resistance of the transition mate-rial between the OSRAM OSTAR base plate and the cooler/heat sink (e.g. thermally conductive paste ≈ 0.1 K/W)R th,JB = Thermal resistance of the OSRAM OSTAR Observation (from data sheet: R th,JB = 2.8 K/W)R th,Heat sink = Thermal resistance of the cooler/heat sink to the environmentthe thermal resistances.In this example, the maximum thermal resis-tance required for cooling of the module can be found by:With the calculated thermal resistance value at hand, a corresponding heat sink can beselected from a manufacturer (see ). Using this setup at the given operating conditions the junction temperature of the module will be at 135°C. If a lower T J is desired, the safety temperature ΔT Safety has to be increased accordingly.In addition to a thermal evaluation by means of a simulation or a computed estimate, it is generally recommended to verify and safe-guard the design with a prototype and ther-mal measurements.ConclusionDeveloped for high power operation with pulsed currents of up to five Amperes, the OSRAM OSTAR Observation IR light source achieves a light output of several Watts, depending on operating parameters.Due to operation at high power levels, ap-propriate thermal management is particularly necessary in order to dissipate the accumu-lated heat and to assure the optimal per-formance and reliability of the module.When developing applications based on the OSRAM OSTAR Observation, it is generally recommended that in addition to thermal simulations, the design should be verified and safeguarded by means of a prototype and thermal measurements.April 8, 2011page 10 of 10Don't forget: LED Light for you is your place to be whenever you are looking for information or worldwide partners for your LED Lighting project.Author: Dr. Claus Jäger, Andreas StichABOUT OSRAM OPTO SEMICONDUCTORSOSRAM is part of the Industry sector of Siemens and one of the two leading lighting manufactur-ers in the world. Its subsidiary, OSRAM Opto Semiconductors GmbH in Regensburg (Germany), offers its customers solutions based on semiconductor technology for lighting, sensor and visu-alization applications. OSRAM Opto Semiconductors has production sites in Regensburg (Ger-many) and Penang (Malaysia). Its headquarters for North America is in Sunnyvale (USA), and for Asia in Hong Kong. OSRAM Opto Semiconductors also has sales offices throughout the world. For more information go to .All information contained in this document has been checked with the greatest care. OSRAM Opto Semiconductors GmbH can however, not be made liable for any damage that occurs in connection with the use of these contents.。

Highly Efficient α-Sialylation by Virtue of Fixed Dipole Effects of N-Phtha

Highly Efﬁcient a -Sialylation by Virtue of Fixed Dipole Effects of N -Phthalyl Group:Application to Continuous Flow Synthesis of a (2-3)-and a (2-6)-Neu5Ac-Gal Motifs by MicroreactorShin-ichi Tanaka,Takashi Goi,Katsunori Tanaka,and Koichi FukaseDepartment of Chemistry,Graduate School of Science,Osaka University,Toyonaka,Osaka,JapanHighly a -selective sialylation of sialic acid N -phenyltriﬂuoroacetimidate with variousgalactose and lactose acceptors has been achieved by introducing the C-5N -phthalylgroup on the donor.The “ﬁxed dipole effect”of the N -phthalyl group was proposed toexplain the high reactivity and a -selectivity .The microﬂuidic system was applied to thepresent a -sialylation,which is amenable to large-scale synthesis.The N -phthalyl groupwas removed by treatment with methylhydrazine acetate,for which protocol can bereadily applied to the synthesis of a variety of sialic acid-containingoligosaccharides.Received February 6,2007;Accepted July 24,2007Address correspondence to Koichi Fukase,Department of Chemistry,Graduate Schoolof Science,Osaka University,Machikaneyama 1-1,Toyonaka,Osaka 560-0043,Japan.E-mail:koichi@chem.sci.osaka-u.ac.jpJournal of Carbohydrate Chemistry,26:369–394,2007Copyright #Taylor &Francis Group,LLCISSN:0732-8303print 1532-2327onlineDOI:10.1080/07328300701634796369Keywords a -Sialylation,N -Phthalyl group,Fixed dipole effects,Microreactor,OligosaccharidesN -Acetylneuramic acid (Neu5Ac),the most abundant sialic acid congener in nature,is found at the termini of glycoproteins and glycolipids on mammalian cell surfaces,usually linked with galactose or N -acetylgalactosamine through a (2-3)or a (2-6)sialoglycoside bonds.Since Neu5Ac on the cell surfaces plays diverse and important roles in cell /cell interaction processes,[1]such as pathogen /host recognition,tumor metastasis,and cell differentiation /prolifer-ation,much effort has been devoted to the development of efﬁcient and stereo-selective synthesis of a (2-3)and a (2-6)-Neu5Ac-Gal units in order to further investigate their biological functions.[2,3]However,an efﬁcient and general sia-lylation with high a -selectivity still has not been fully realized,because (1)the presence of the electron-withdrawing carboxylic acid groups at C-2of the sialyl acid donors deactivates the oxocarbenium ions,thus electronically and steri-cally interfering with efﬁcient sialylation.This leads to the formation of a sig-niﬁcant amount of the dehydrated byproduct,2,3-glycal.In addition,(2)the absence of the neighboring participation group at C-3cannot ensure the stereo-chemical outcome for the a -selective sialylation.This inherent reactivity of the sialyl donor renders the a -selective sialylation as one of the most difﬁcult [4]and challenging topics in the ﬁeld of oligosaccharide synthesis.[5]Recently,Cai and Yu have successfully enhanced the reactivity of sialic aciddonors by utilizing phenyltriﬂuoroacetimidate as a leaving group,and achieved efﬁcient sialylation with a variety of acceptors in 59%to 90%yields:while (2-3)-Neu5Ac-Gal synthesis has been realized in 81%yield (a :b ¼3:1),the corre-sponding a -selective (2-6)-sialylation was achieved in 61%yield.[6]Kiso and coworkers [7]and Takahashi and coworkers [8]have used the C-5-N -Troc-protected thiophenyl derivatives as the sialic acid donors and achieved good a -selectivity,namely ,a :b ¼54:10for the (2-3)-sialylation case.[7]Apparently,one of the most exciting achievements in this ﬁeld is the a -(2-8)-linkage formation between the sialosides,quite recently realized by Kiso’s [9a]and Takahashi’s [9b]groups.Especially,Takahashi’s group has utilized the 4-O ,5-N -oxazolidinone-protecting group both on the sialoside donor and the acceptor and realized both a -(2-9)-and a -(2-8)-oligosialoside synthesis with excellent selectivity.[9b]In our program directed toward the establishment of a general and practicalsynthesis of N -linked oligosaccharides and other neuramic acid-containing natural products,highly yielding and a -selective sialylation is essential.The recent successful precedents mentioned above led us to utilize the phenyl-triﬂuoroacetimidate donor and to pursue the possibility of increasing the a -selectivity by modifying the C-5-N -protecting groups of the sialic acid donors (i.e.,the amide groups of which dipole moments direct the stereochemical course of glycosylation and /or the carbonyls take part in the neighboring groupS.-i.Tanaka et al.370participation).In this paper,we disclose in detail[10]highly efﬁcient sialylation with excellent a-selectivity by using the N-phthalyl group,which led to a general synthesis of the a(2-3)-and a(2-6)-Neu5Ac-Gal moieties.The method is applied to microﬂuidic a-sialylation in pursuit of a scaled-up synthesis of neuramic acid-containing compounds.The possible mechanisms for the enhanced a-selectivity based on the conformational analysis and electronic property calculations are also described.For the sialic acid donors,we planned six differently protected derivatives on the C-5nitrogen,namely,acetyl(2a),Troc(2b),bis-acetyl(2c),dimethylma-leoyl(DMM,2d),tetrachlorophthalyl(TCP,2e),and phthalyl(Pht,2f)(Sch.1). These donors were easily prepared from thioglycoside1,[11]according to Higuchi’s procedure:[3e](1)deacetylation,(2)protection of the C-5nitrogen, (3)peracetylation of the remaining hydroxyls,(4)hydrolysis of the thioglyco-side,and(5)phenyltriﬂuoroacetimidate formation.a-Selective(2-6)-sialylation trials using donors2a–2f thus prepared and 1-O-allyl-2,3-O-benzoylgalactose3,appropriately protected for further func-tional group manipulation,are shown in Table1.First,the reactivity of the sialy donors2a–2f was screened using50mg of each sample(Table1).All reac-tions were performed at2788C in the presence of TMSOTf as the Lewis acid activator,using1.5equivalents of acceptor3with respect to the donors.Propio-nitrile was used as the optimal solvent,by taking advantage of“nitrile solvent effect.”[13]The reaction of N-mono-acetyl donor2a with acceptor3provided the corresponding disacchalide4a in good yield(entry1,93%)and with moderate selectivity(a:b¼77:23).It is noteworthy that,when N-Troc derivative2b wasused(entry2),the reaction was signiﬁcantly accelerated(6h for N-AcandScheme1:Preparation of sialic acid donors2a–f bearing a variety of N-protected groups.Highly Efﬁcient a-Sialylation37130min for N -Troc),and a -selectivity also increased up to a :b ¼92:8.This observation is in accordance with that of Kiso and coworkers.[7]Encouraged by these promising results,we then examined the N -bis-acylated donors 2c –2f .Bis-N -acetyl derivative 2c gave the corresponding dis-acchalide 4c in moderate yield and with moderate a -selectivity (75%and a :b ¼72:28,entry 3),similar to that observed for monoacylate 2a (entry 1).However,we were glad to ﬁnd that,when two acyl groups on the C-5nitrogen were ﬁxed within the ﬁve-membered rings,the a -selectivity increased dramatically.Thus,N -DMM-and N -TCP-protected donors 2d and 2e successfully provided disacchalides 4d and 4e in 94%and 87%yields,respectively,and both with excellent a -selectivity (a :b ¼96:4,entries 4and5).Furthermore,the utilization of the N -Pht-protected donor 2f resulted in perfect a -selectivity and excellent yield (92%on 50-mg scale,entry 6).It is worthwhile mentioning that,when the solvent was exchanged from propioni-trile to the noncoordinating dichloromethane,the stereoselectivity was reversed (entry 7,a :b ¼9:91),indicating the importance of the “nitrile solvent effect”in order to obtain good a -selectivity.However,when the scale of the reaction was increased by only two,the product yield markedly decreased,although the a -selectivity remained high.Thus,the 100-mgTable 1:a -Selective (2-6)-sialylation Using 2a–f .aEntryDonor Solvent Temp Time Product Yield (%)b a :b c 12a EtCN 2788C 6h 4a 9377:2322b EtCN 2788C 30min 4b 8492:832c EtCN 2788C ,5min 4c 7572:2842d EtCN 2788C ,5min 4d 9496:452e EtCN 2788C ,5min 4e 8796:462f EtCN 2788C 30min 4f 92d a only 72f CH 2CI 2rt ,5min 4f 879:9182f EtCN 2788C 30min 4f 60e a only a All sialylations were performed using 1.5equiv of acceptor 3relative to donors 2a –2f .The mixture of anomeric stereoisomers for imidates 2a –2f was used.b Isolated yields.c The a /b -ratio was determined by NMR analysis:a -and b -isomers were identiﬁed based on the empirical rule for their characteristic proton chemical shifts.[12]d Yield at 50mg-scale of 3.e Yield at 100mg-scale of 3.S.-i.Tanaka et al.372scale reaction of 3gave only 60%of a -sialoside accompanied by a signiﬁcant amount of a glycal byproduct (entry 8).The decrease in sialylation efﬁciency observed in entry 8might be due tothe high reactivity of 2f .For such a case,precise reaction control is very difﬁ-cult under the conventional batch process conditions,especially when the reaction is scaled up.Thus,the disorder of the reaction factors in the scaled-up batch reaction,that is,(1)precise temperature control;(2)mixing efﬁciency between acceptor,donor,and Lewis acid;and (3)reaction time might lead to the glycal production.In order to circumvent these problems,we used a continuous ﬂow microreactor,which is reported to realize efﬁcient mixing and fast heat transfer and,therefore,is recognized as innovative technology in recent organic synthesis.[14]Once the reaction conditions are optimized for the small-scale reaction,the same conditions are directly applied to a large-scale synthesis,since the reaction is conducted under the ﬂow process conditions.[15]An application of the microﬂuidic system to the glycosylation reaction was ﬁrst reported by Seeberger and coworkers on a -mannosylation.[16a]We also have established an efﬁcient microﬂuidic glycosylation in combination with the afﬁnity separation method.[16b]For the present microﬂuidic sialylation,a propionitrile solution of sialyldonor 2f and acceptor 3with various concentrations was mixed with TMSOTf solution in dichloromethane at 2788C using an IMM micromixer [17]at the ﬂow rate of 1.0mL /min (Table 2).After the reaction mixture was allowed to ﬂow at 2788C for additional 47sec through a reactor tube (F ¼1.0mm,Table 2:Optimization of a -(2-6)-sialylation between donor 2f and acceptor 3usingmicroreactor.EntryDonor 2f (M)Acceptor 3(M)TMSOTf (M)Yield of 4f (%)a :b a 10.150.10.0814a only 20.150.10.1588a only 30.20.10.15.99a only a Based on 1H NMR analysis.Highly Efﬁcient a -Sialylation 373l ¼1.0m),the mixture was quenched by another ﬂow of excess triethylamine dissolved in dichloromethane by using a T-shaped mixer at 2788C.CH 2Cl 2was used as a cosolvent for the microﬂuidic sialylation in order to avoid blockages during the micromixing.By using the mixed solvent system of EtCN /CH 2Cl 2(1:1),the same yield and a -selectivity in batch sialylation was observed as in Table 1,entry 6.When the concentrations of the donor 2f ,acceptor 3,and TMSOTf were adjusted to 0.15M,0.1M,and 0.08M,respect-ively,disaccharide 4f was obtained in only 14%yield and an excess amount of acceptor 3was recovered (entry 1).However,we were pleased to ﬁnd that the yield of 4f dramatically increased (88%)when the concentration of the Lewis acid was increased up to 0.15M (entry 2).Finally,the desired a -sialoside 4f was obtained in quantitative yield by increasing the concentration of the donor 2f to 0.2M (entry 3).The use of excess amounts of donor 2f or TMSOTf under the batch reaction conditions did not improve the sialylation yield,but rather resulted in a large amount of glycal production.It is noted that,by this continuous microﬂow reaction,single a -sialoside 4f was reprodu-cibly obtained without any decrease of the yield.The microﬂuidic reaction suc-cessfully controlled the high reactivity of the sialyl donor 2f for a -sialylation,and efﬁcient and large-scale procedures have now been realized.The excellent a -selectivity achieved for a (2-6)-sialoglycosidation using theN -Pht donor 2f was also applied to the (2-3)-sialylation cases (Table 3).Although poor selectivity (a :b ¼65:35)was obtained by the reaction of 2f with the sterically hindered 4,6-benzylidene-protected monosaccharaide acceptor 5(entry 1),excellent a -selectivity (97:3)was achieved by the reaction with the 1-O -allyl-2-O -benzoyl-6-O -benzyl-protected acceptor 6(entry 2).A slightly lower yield of 77%,compared with the (2-6)-sialylation case,is due to the decreased reactivity of the C-3hydroxyl of acceptor 6,thus giving rise to the 2,3-glycal production (16%).In order to prevent the glycal formation for such a (2-3)-sialylation case,we further examined the more reactive 2-benzyl-protected acceptor 7(entry 3).Although the reaction rapidly proceeded and the glycal byproduct could not be detected from the crude mixtures,both (2-3)-and (2-4)-sialoglycosides 13a and 13b (13a :13b ¼2:1)were produced in 85%total yield as their single a -isomers.The C2-a -conﬁguration in (2-3)-and (2-4)-sialoglycosides 13a and 13b was assigned from the NOEs between methyl protons of the ester and H-4and /or H-6in the neuramic acid moiety.The method was also applied to the lactose-derived disaccharide acceptors,providing the corresponding trisaccharides with excellent a (2-3)-selectivity and moderate yields (entries 4–6).The reaction of 2f with the perbenzoyl-pro-tected lactoses 8and 9gave a (2-3)-trisaccahride derivatives 14and 15as the single stereoisomers in 38%and 43%yields,respectively (entries 4and 5).The yield was increased up to 50%by the reaction with more reactive perben-zylated acceptor 10,although the a -selectivity slightly decreased (entry 6,S.-i.Tanaka et al.374Table 3:a -Selective (2-3)-sialylation between 2f and a variety of acceptors.aEntryAcceptor Condition Product Yield (%)b a :b c1EtCN,2788C,5min 84%65:352EtCN,2788C,5min 77%97:33d ,e EtCN,2788C,5min 85%a only both for a (2-3)and a (2-4)4EtCN,2788C,15min 38%a only(continued )375Table 3:Continued.EntryAcceptor Condition Product Yield (%)b a :b c5EtCN,2788C,15min 43%a only6EtCN,2788C,1h 50%93:7aAll sialylations were performed using 1.5equiv of acceptor 5–10relative to donor 2f .b Isolated yields.c The a /b -ratio was determined by NMR analysis.[12]d Products ratio of a (2-3)and b (2-4)sialosides was 2:1.Their structures were analyzed after benzoylation.e PNP ¼p -Nitrophenyl.376a :b ¼93:7).The main byproduct of the sialylation using the disaccharide accep-tors 8and 9was the glycal derivative of 2f .The sterically bulkier disaccharides would not react smoothly with the donor cation derived from 2f ,but instead the 3H proton of the donor cation was subtracted to give rise to the glycal.In anticipation of the efﬁcient mixing effects between donor,acceptor,and acid,the microﬂuidic system was again applied to this case (Table 4).The per-benzoylated lactose 9was used for the microﬂuidic sialylation trials,since the functional group manipulation after the glycosylation was easier than the cor-responding perbenzylated acceptor 10.After the optimization of the micromix-ing conditions,trisaccharide 15was obtained in 62%yield as a single a -stereoisomer (entry 3),when 0.3M of the donor 2f ,0.1M of the acceptor 9,and 0.3M of TMSOTf were combined by the IMM micromixer.This is about a 20%increase in the yield compared with that of the batch reaction (43%yield in Table 3,entry 5).By taking the results obtained in Table 2and Table 4together,the microﬂuidic reaction enabled a -selective sialylation for both a -(2-6)and a -(2-3)cases in higher yields than the conventional batch process.In order to understand the good reactivity and a -selectivity observed for the C-5-N -phthalyl-and the other protected donors,conformational analysis of the intermediary oxocarbenium ions 17a –17f ,derived from the imidates 2a (N -Ac),2b (N -Troc),2c (N -Ac 2),and 2f (N -Pht),was performed based on the molecular mechanics calculations with the MMFF94s /MonteCarlo method using Spartan 02software (Fig.1a–d).[18,19]The boat-like folded con-formations were found as the lowest-energy conformations for both Table 4:Optimization of a -(2-3)-sialylation between donor 2f and acceptor 9usingmicroreactor.EntryDonor 2f (M)Acceptor 9(M)TMSOTf (M)Yield of 15(%)a :b a 10.10.150.0521a only 20.30.10.1550a only 30.30.10.362a only a Based on 1H NMR analysis.Highly Efﬁcient a -Sialylation377monoacylates 17a (N -Ac)and 17b (N -Troc)(Fig.1a,b).For these energy-mini-mized conformations,both N -acetyl and N -Troc carbonyls are thought to be participating in the electrostatic interaction with the oxocarbenium ions,thus stabilizing the intermediates.Although the observed a -selectivity is mainly caused by the nitrile solvent effects as exempliﬁed by both Kiso’s and Takahashi’s experiments with 5-N -Troc derivatives,[7,8]the additional confor-mational preferences of Figures 1a and 1b may also lead to the attack of the acceptor from the backside of the molecule and thus high a -selective sialylation would result.The carbonate (O-C 55O)group would be involved in a stronger interaction with the carbenium ion than the acyl (C 55O)group;thereby,the higher a -selectivity of Troc-protected 2b would result.On the other hand,chair-like extended conformations were obtained for both N -bis-acyl derivatives 17c (N -Ac 2)and 17f (N -Pht)as their energy-mini-mized conformations (Fig.1c,d).Since the N -Ac 2and N -Pht moieties deter-mine the totally different reactivity and selectivity toward theglycosylation Figure 1:Optimized structures of oxocarbenium ions 17a –17f by molecular mechanics calculation with MMFF94s /MonteCarlo Method Using Spartan 02Software.The most stable conformations are shown in (a–d):Based on the experimental results in Table 1,thecalculation was mainly performed to provide a rationale for the electronic effects of 5N -substitutents on oxocarbenium ion.Accordingly,the C-6alkyl side chain was replaced by a simple methyl group in order to simplify the conformational analysis.Among the optimized conformations of 17c ,the trans -diacetyl conformation was obtained as the second lowest structure at 0.1kcal /mol higher energy level.S.-i.Tanaka et al.378observed in Table 1,their local conformations and electronic properties were further investigated (Fig.2).Thus,the geometries of the simpliﬁed Me-N Pht and Me-N -Ac 2models were optimized at the DFT /BLYP /6-31G Ãlevel,and on these obtained minima,the dipole moments (m )were then calculated by using Gaussian 03W Software.[20]While one minimum was found,as expected,for the conformationally rigid Me-N Pht (Figure 2a,the dipole moment shown with a red arrow),two absolute minima were found for Me-N -Ac 2,where the trans isomer is more stable than the cis isomer by 3.57kcal /mol (Fig.2b,c).In the trans isomer,the dipole moment is directed from the nitrogen atom toward one of the carbonyls while it is aligned toward the N -Me direction in the cis isomer.Therefore,in the oxocarbenium ion intermediate 17f (Fig.1d),the ﬁxed dipole of the N -Pht may possibly facilitate the nitrile solvent participation from the b -face of the ly,the ﬁxed dipole moment in N -Pht aligned on the same plane as the sugar six-membered ring would interact with the dipoles of the attacking nitrile solvent due to the favorable dipole /dipole arrangement in space.It is noted that the rotation around the C-N bond in 17f does not change the direction of the dipole of N -Pht (see yellow arrow in Fig.1d);thus,the strong dipole /dipole effects may be anticipated.Furthermore,the ﬁxed dipole may also stabilize the cation intermediate 17f by interacting with the dipole of oxocarbonium ion.This stabilized cation can be trapped by the nitrile solvent from the b -side of the molecule,namely,due to the stereoelectronic effect,which in turn is attacked by the acceptor from the a -face of the molecule via S N 2-type substitution reaction.The signiﬁcant solvent effects observed in Table 1(entries 6and 7)support this rationale.A similar dipole stabilized carbocation intermediate has also been proposed by Wong and coworkers in order to explain the highly a -selective sialylation using the C 5-N -azide sialoside donor.[2p]Figure 2:Optimized structures and dipole moments of simpliﬁed N -Pht and N -Ac 2moieties by DFT /BLYP /6-31G Ãlevel calculation using Gaussian 03W software.Highly Efﬁcient a -Sialylation 379On the other hand,no such strong dipole /dipole interactions can be expected for the conformationally ﬂexible bis-N -acylate oxocarbenium ion 17c .As predicted from the dipole orientations of N -Ac 2in Figures 2b and 2c,when two acetyl groups on the nitrogen and the N-C bond rotate freely (see yellow arrows in Fig.1c),the dipoles are randomized;that is,the dipole is not ﬁxed as parallel to the pyrane plane.This offset of the dipole orientations of N -Ac 2might therefore decrease the reactivity and a -selectivity of 17c ,compared with that of 17f .Although many other effects,including the solvation and temperature effects,operate the total reactivity and stereochemical results on the sialylation,the conformational and “ﬁxed dipole”analysis performed on 17c and 17f supported the experimentally observed high a -selectivity of 2f ,the 5-N phthalyl-protected sialoside donor.Finally,removal of the N -phthalyl group of di-and trisaccharides 4f ,12,15,and 16was attempted (Table 5).Hydrazine acetate,a common reagent for the deprotection of the N -phthalyl group,unexpectedly hydrogenated the 1-O -allyl moiety of a (2-6)-disaccharide 4f into the O -propyl group.The problem was cir-cumvented by using the corresponding methylhydrazine acetate.The reaction of 4f with excess methylhydrazine acetate in ethanol at 808C provided a Table 5:Removal of N -phthalylgroup.EntrySubstrate Product Yield (%)184273a345a Corresponding hydrazone was obtained in 11%yield as a byproduct.S.-i.Tanaka et al.380Highly Efﬁcient a-Sialylation381 complex mixture of the products consisting of partially deacetylated com-pounds,which without the puriﬁcation was acetylated with Ac2O in pyridineto give N-Ac derivative18in84%yield(entry1).Similarly,the treatment ofa(2-3)-disaccharide and trisaccharides12and15yielded the correspondingN-Ac derivatives19and20in73%and45%yields,although the corresponding hydrazone derivatives were obtained as the main byproducts for these a(2-3)-sialoside cases.In summary,we have achieved highly efﬁcient a-selective sialylation toward the synthesis of the a(2-6)-and a(2-3)-Neu5Ac-Gal units by tuningthe electronic properties of the C-5nitrogen-protecting groups.We proposedtheﬁxed dipole moment concept in order to explain the high reactivity and excellent a-selectivity observed when the N-phthalyl group was utilized. Furthermore,the microﬂuidic system was applied to the present a-sialylation,and an efﬁcient route to large-scale synthesis was established.The C5-N-phthalyl group utilized for a-selective sialylation was readily removed(i.e.,by treatment with methylhydrazine acetate),thereby enabling efﬁcient and general procedures for easy access to the sialic acid-containing library or complex N-linked glycans.Research directed along this line is now in progress in our laboratory.EXPERIMENTALAll commercially available reagents were used without further puriﬁcation. Dichloromethane and propionitrile were reﬂuxed over and distilled fromCaH2.Preparative separation was usually performed by column chromato-graphy on silica gel(FUJI silysia LTD,BW-200and BW-300)and by thinlayer chromatography on silica gel(Merck,20Â20cm,Silica gel60F254,1mm).1H NMR spectra were recorded on a JEOL a-500spectrometer and chemical shifts were represented as d values relative to the internal standard TMS.ESI-MS was measured on an Applied Biosystems Mariner.High-resolution mass spectra(HRMS)were measured on a JEOL JMS-T100LC mass spectrometer.Representative Procedure for N-protected Sialyl DonorsMethyl4,7,8,9-Tetra-O-acetyl-3,5-dideoxy-5-phthalimido-D-glycero-D-galacto-2-nonulopyranosylonate-2-N-phenyltriﬂuoroacetimidate(2f):To a solution of methyl(phenyl5-acetamide-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-2-thio-D-glycero-D-galacto-2-nonulopyranosid)onate(1.5g, 2.6mmol)in MeOH(25mL)was added methanesulfonic acid(190m L,2.6mmol)andthe resulting mixture was stirred at608C for24h.After the solution was cooled to rt,the mixture was concentrated in vacuo.Without puriﬁcation ofthe intermediary amine derivative,NaOMe(530m L,2.6mmol)was added toa crude material dissolved in anhydrous THF (25mL)to neutralize at rt under Ar atmosphere.After being stirred at rt for 10min,phthalic anhydride (760mg,5.1mmol)and Et 3N (720m L,5.1mmol)were added and the reaction mixture was stirred at 708C overnight.After the solution was cooled to rt,the mixture was concentrated in vacuo.The residue was dissolved in EtOAc;washed with saturated aqueous NaHCO 3,1M HCl,and brine;dried over Na 2SO 4;ﬁltered;and concentrated in vacuo to give the crude product,which was roughly puriﬁed by column chromatography on silica gel (6%MeOH in chloroform)to give the intermediate N -Phth derivative as colorless needles (798mg,62%).1H NMR (500MHz,CD 3OD)d 7.93–7.91(m,1H,SPh),7.66–7.64(m,2H,Phth),7.62–7.60(m,1H,SPh),7.57–7.52(m,2H,Phth),7.45–7.40(m,3H,SPh),4.77(d,J ¼10.5Hz,1H,H-6),4.33(ddd,J ¼4.70,9.80,11.2Hz,1H,H-4),4.18(brt,J ¼10.3Hz,1H,H-5),4.13(brd,J ¼8.25Hz,1H,H-7),3.91–3.85(m,3H,H-8,H-9a,H-9b), 3.60(s,3H,CO 2CH 3), 2.76(dd,J ¼4.55,13.5Hz,1H,H-3eq),2.05(dd,J ¼11.7,13.4Hz,1H,H-3ax);ESI-MS m /z calcd for C 24H 25NO 9SNa (M þNa)þ526.11,found 526.11.To a solution of N -Phth derivative obtained above (280mg,560m mol)in pyridine (1mL)was added Ac 2O (1mL)at rt under Ar atmosphere.After the solution was stirred at rt overnight,the mixture was concentrated in vacuo and the residue was coevaporated with toluene three times.The residue was dissolved in EtOAc,and the organic layer was washed with saturated aqueous NaHCO 3,1M HCl solution,and brine;dried over Na 2SO 4;ﬁltered;and concentrated in vacuo to give the crude product.The residue was puriﬁed by silica-gel column chromatography (17%ethyl acetate in toluene)to give N -Phth tetraacetate as colorless needles (61%for three steps):1H NMR (500MHz,CDCl 3)d 7.79(m,2H,Phth),7.68–7.66(m,2H,Phth),7.53–7.51(m,2H,SPh),7.32–7.28(m,3H,SPh),5.89(td,J ¼5.15,10.8,10.8Hz,1H,H-4),5.71(dd,J ¼2.45,10.5Hz,1H,H-6),5.20(dd,J ¼2.45,3.65Hz,1H,H-7),4.93(ddd,J ¼2.85,7.00,8.23Hz,1H,H-8), 4.36(dd,J ¼2.60,12.3Hz,1H,H-9a), 4.14(t,J ¼10.4Hz,1H,H-5), 3.96(dd,J ¼7.75,12.4Hz,1H,H-9b), 3.62(s,3H,CO 2CH 3), 2.72(dd,J ¼5.50,13.8Hz,1H,H-3eq),2.04(s,3H,Ac),1.90(s,3H,Ac),1.87(s,3H,Ac),1.75(s,3H,Ac),2.03(dd,J ¼11.3,14.4Hz,1H,H-3ax);ESI-MS m /z calcd for C 32H 33NO 13SNa (M þNa)þ694.16,found 694.16.To a solution of N -Phth tetraacetate obtained above (50mg,74m mol)in acetone were added NBS (27mg,150m mol)and water (4.0mg,220m mol)at rt.After the solution was stirred at rt for 1h,the mixture was quenched by 10%aqueous Na 2S 2O 3and extracted with EtOAc.The organic layer was washed with saturated aqueous NaHCO 3and brine,dried over Na 2SO 4,ﬁltered,and concentrated in vacuo to give the crude product.The residue was puriﬁed by column chromatography on silica gel (chloroform)to give the hydrolyzed derivative as colorless needles (33mg,75%):1H NMR (500MHz,CDCl 3)d 7.88–7.80(m,2H,Phth),7.74–7.72(m,2H,Phth), 5.82(ddd,S.-i.Tanaka et al.382。

SmartLine STG700 STG70L 压力传感器技术说明书

SmartLineTechnical InformationSTG700 SmartLine Gauge Pressure Specification 34-ST-03-122, Jan 2021IntroductionPart of the SmartLine® family of products, the STG700 andSTG70L are suitable for monitoring, control and dataacquisition featuring piezoresistive sensor technologycombining pressure sensing with on chip temperaturecompensation capabilities providing high accuracy, stabilityand performance over a wide range of applicationpressures and temperatures. The SmartLine family is alsofully tested and compliant with Experion ® PKS providingthe highest level of compatibility assurance and integrationcapabilities. SmartLine easily meets the most demandingapplication needs for pressure measurement applications.Best in Class Features:∙Accuracies up to 0.065% of span∙Stability up to 0.020% of URL per year for 10 years∙Automatic temperature compensation∙Rangeability up to 100:1∙Response times as fast as 100ms∙Easy to use and intuitive display capabilities∙Intuitive External Zero, Span and configuration capability∙Comprehensive on-board diagnostic capabilities∙Integral Dual Seal design for safety based on ANSI/NFPA 70-202 and ANSI/ISA 12.27.0∙Full compliance to SIL 2/3 requirements∙Modular design characteristics∙Available with additional 4-year warrantyCommunications/Output Options:∙HART ® (version 7.0)Figure 1 – STG700 Dual Head and Inline Gauge Pressure Transmitters feature field-proven piezoresistive sensor technology Span & Range Limits:ModelURL psi(bar)LRLpsi (bar)Min Span STG735/STG73S 50 (3.5) -14.7 (-1.0) 0.5 (0.035) STG745/STG74S 500 (35) -14.7 (-1.0) 5 (.35)STG775/STG77S 3000 (210) -14.7 (-1.0) 30 (2.1) STG78S 6000 (420) -14.7 (-1.0) 60 (4.2)STG79S 10000 (690) -14.7 (-1.0) 100 (6.9)2 STG700 Smart Pressure TransmitterDescriptionThe SmartLine family pressure transmitters are designed around a high performance piezo-resistive sensor. This one sensor integrates multiple sensors linking process pressure measurement with on-board static pressure (GP Models) and temperature compensation measurements.Indication/Display OptionStandard LCD Display Featureso Modular (may be added or removed in the field)o Supports HART protocol varianto0, 90,180, & 270 degree position adjustmentso Configurable (HART only) and standard (Pa, KPa, MPa, KGcm2, Torr, ATM, inH2O, mH2O, bar, mbar,inHG, FTH2O, mmH2O, mm HG, & psi) measurementunits.o 2 Lines 6 digits PV (9.95H x 4.20W mm) 8 Characters o Square root output indication (√)o Write protect Indicationo Built in Basic Device Configuration through Internal or External Buttons – Range/Engineering Unit/Loop Test /Loop Calibration/Zero /Span Settingo Multiple language capability (EN, RU)DiagnosticsSmartLine transmitters all offer digitally accessible diagnostics which aid in providing advanced warning of possible failure events minimizing unplanned shutdowns, providing lower overall operational costsSystem Integrationo SmartLine communications protocols all meet the most current published standards for HART.o All ST 700 units are Experion tested to provide thehighest level of compatibility assurance Configuration ToolsExternal Two Button Configuration OptionSuitable for all electrical and environmental requirements, SmartLine offers the ability to configure the transmitter and display, for all basic parameters, via two externally accessible buttons when a display option isselected. Zero/span capabilities are also optionally available via two external buttons with or without selection of the display option.Internal Two Button Configuration OptionThe Standard display has two buttons that can be used for Basic configuration such as re ranging, PV Engineering unit setting, Zero/Span settings, Loop testing and calibration functions.Hand Held ConfigurationSmartLine transmitters feature two-way communication and configuration capability between the operator and the transmitter. All Honeywell transmitters are designed and tested for compliance with the offered communication protocols and are designed to operate with any Standards compliant handheld configuration device.Personal Computer ConfigurationField Device Manager (FDM) Software and FDM Express are also available for managing HART device configurations.Modular DesignTo help contain maintenance & inventory costs, all ST 700 transmitters are modular in design supporting the user’s ability to replace meter bodies, standard displays or electronic modules without affecting overall performance. Each meter body is uniquely characterized to provide in-tolerance performance over a wide range of application variations in temperature and pressure.Modular Features∙Meter body replacement∙Add or remove standard displays∙Add or remove lightning protection (terminalconnection)With no performance effects, Honeywell’s unique modularity results in lower inventory needs and lower overall operating costs.STG700 Smart Pressure Transmitter3Performance SpecificationsReference Accuracy: (conformance to +/-3 Sigma)Table 1ModelURLLRLMin SpanMaximum Turndown Ratio Stability (% URL/Year for 10 years)Reference Accuracy 1,2 (% Span) StandardS t a n d a r d A c c u r a c ySTG73550 psi (3.5 bar) -14.7 psi (-1.0 bar) 0.5 psi (.035 bar) 100:1 0.020 0.065STG73S 50 psi (3.5 bar) -14.7 psi (-1.0 bar) 0.5 psi (.035 bar) STG745 500 psi (35 bar) -14.7 psi (-1.0 bar) 5 psi (.35 bar) STG74S 500 psi (35 bar) -14.7 psi (-1.0 bar) 5 psi (.35 bar) STG775 3000 psi (210 bar) -14.7 psi (-1.0 bar) 30 psi (2.1 bar) STG77S 3000 psi (210 bar) -14.7 psi (-1.0 bar) 30 psi (2.1 bar) STG78S 6000 psi (420 bar) -14.7 psi (-1.0 bar) 60 psi (4.2 bar) STG79S10000 psi (690 bar)-14.7 psi (-1.0 bar)100 (6.9 bar)Zero and span may be set anywhere within the listed (URL/LRL) range limitsAccuracy, Span and Temperature Effect: (Conformance to +/-3 Sigma)Table 2Accuracy 1,2 (% of Span)Combined Zero & Span temperature Effect (% Span / 28o C(50o F))Model URLReferenceTurndown ABC(see URL units)D E S t a n d a r d A c c u r a c ySTG73550 psi (3.5 bar) 16.7:1 0.005 0.0603 (0.21) 0.070 0.008 STG73S 50 psi (3.5 bar) 8:1 6 (0.42) 0.100 0.015 STG745 500 psi (35 bar) 20:1 25 (1.75) 0.075 0.013 STG74S 500 psi (35 bar) 20:1 25 (1.75) 0.100 0.020 STG775 3000 psi (210 bar) 8.5:1 350 (24.5) 0.075 0.013 STG77S 3000 psi (210 bar) 8.5:1 350 (24.5) 0.100 0.025 STG78S 6000 psi (420 bar) 10:1 600 (42) 0.100 0.070 STG79S10000 psi (690 bar) 8:10.025 0.040 1250 (86.25)0.2000.170Turn Down EffectTemp EffectTotal Performance (% of Span):Total Performance Calculation : = +/- √ (Accuracy)2 + (Temperature Effect)2Total Performance Examples (for comparison): (standard accuracy, 5:1 Turndown, +/-50 o F (28o C) shift) STG735 @ 10 psi: 0.128% of span STG73S @ 10 psi: 0.187% of spanSTG745 @ 100 psi: 0.154% of span STG74S @ 100 psi: 0.210% of spanSTG775 @ 600 psi: 0.154 % of span STG77S @ 600 psi: 0.234% of span STG78S @ 1200 psi: 0.455% of span STG79S @ 2000 psi: 1.052% of spanTypical Calibration Frequency:Calibration verification is recommended every two (2) yearsNotes:1. Terminal Based Accuracy - Includes combined effects of linearity, hysteresis, and repeatability. Analog output adds 0 .006% of span.2. For zero based spans and reference conditions of: 25 o C (77 o F) for LRV > = 0 psia, 10 to 55% RH, and 316 Stainless Steel barrierdiaphragm.4 STG700 Smart Pressure Transmitter Operating Conditions – All ModelsParameter ReferenceConditionRated Condition Operative Limits Transportation andStorage︒C ︒F ︒C ︒F ︒C ︒F ︒C ︒FAmbient Temperature125±1 77±2 -40 to 85 -40 to 185 -40 to 85 -40 to 185 -55 to 120 -67 to 248 Meter Body Temperature 25±1 77±2 -40 to 110 -40 to 230 -40 to 125 -40 to 257 -55 to 120 -67 to 248 Humidity %RH10 to 55 0 to 100 0 to 100 0 to 100 Vac. Region – Min. PressuremmHg absoluteinH2O absoluteAtmosphericAtmospheric25132 (short term ) 21 (short term ) 2Supply Voltage Load Resistance 10.8 to 42.4 Vdc at terminals0 to 1,440 ohms (as shown in Figure 2)Maximum AllowableWorking Pressure (MAWP)3, 4(ST700 products are rated to Maximum Allowable Working Pressure. MAWP depends on Approval Agency andtransmitter materials ofconstruction.)STG735: 50 psi (3.5 bar) STG73S: 50 psi (3.5 bar ) STG745: 500 psi (35 bar) STG74S: 500 psi (35 bar ) STG775: 3000 psi (210 bar ) STG77S: 3000 psi (210 bar ) STG78S: 6000 psi (420 bar ) STG79S: 10000 psi (690 bar )LCD Display operating temperature -20︒C to +70︒C Storage temperature -30︒C to 80︒C.2 Short term equals 2 hours at 70︒C (158︒F).3 Units can withstand overpressure of 1.5 x MAWP without damage.4Consult the factory for MAWP of ST 700 transmitters with CRN approval.5 Silicone minimum temperature rating is -40︒C (-40︒F). CTFE minimum temperature rating is -30︒C (-22︒F).Figure 2 - Supply voltage and loop resistance chart & calculationsSTG700 Smart Pressure Transmitter 52 Hastelloy® C-276 or UNS N102764 Supplied as 316 SS or as Grade CF8M, the casting equivalent of 316 SS.5 Carbon Steel heads are zinc-plated and not recommended for water service due to hydrogen migration. For that service, use 316stainless steel wetted Process Heads.6 Hastelloy® C-276 or UNS N10276. Supplied as indicated or as Grade CW12MW, the casting equivalent of Hastelloy® C-2766 STG700 Smart Pressure Transmitter Communications Protocols & DiagnosticsHART ProtocolVersion:HART 7Power SupplyVoltage: 10.8 to 42.4Vdc at terminalsLoad: Maximum 1440 ohms See Figure 2.Minimum Load: 0 ohms. (For handheld communications aminimum load of 250 ohms is required)Standard DiagnosticsST 700 top level diagnostics are reported as either criticalor non-critical and readable via the DD/DTM tools orintegral display as shown.Non-Critical DiagnosticsRefer to ST 700 manuals for additional level diagnosticinformation.STG700 Smart Pressure Transmitter 78 STG700 Smart Pressure TransmitterSTG700 Smart Pressure Transmitter 910 STG700 Smart Pressure TransmitterSTG700 Smart Pressure Transmitter 11 Notes:1.Operating Parameters:Voltage= 11 to 42 V DC Current= 4-20 mA Normal2.Intrinsically Safe Entity Parametersa. Analog/ DE/ HART Entity Values:Vmax= Ui = 30V Imax= Ii= 105mA Ci = 4.2nF Li =984 uH Pi =0.9WTransmitter with Terminal Block Revision E or LaterVmax= Ui = 30V Imax= Ii= 225mA Ci = 4.2nF Li = 0 Pi =0.9WNote : Transmitter with Terminal Block Revision E or laterThe revision is on the label that is on the module. There will be two lines of text on the label:∙First is the Module Part #: 50049839-001 or 50049839-002∙Second line has the supplier information, along with the REVISION:XXXXXXX-EXXXX, THE “X” is production related, THE POSITION of the “E” IS THE REVISION.Other Certification OptionsMaterialso NACE MRO175, MRO103, ISO1515612 STG700 Smart Pressure Transmitter Mounting & Dimensional DrawingsReference Dimensions:millimetersinchesMounting Configurations: (Dual head design)Dimensions: (Dual head design)Figure 3 – Typical mounting dimensions of STG735, STG745 & STG775 for reference R efer to the User’s manual (34-ST-25-44) for full details on mounting and installation.STG700 Smart Pressure Transmitter 13Reference Dimensions:millimetersinchesMounting Configurations (Inline Designs)Dimension (Inline Design)Figure 4 – Typical mounting dimensions of STG74S, STG77S, STG78S, & STG79S for reference R efer to the User’s manual (34-ST-25-44) for full details on mounting and installation.14 STG700 Smart Pressure TransmitterModel STG700Gauge Pressure TransmittersModel Selection Guide1a STG735,745,775 supplied via 1/2" flange adapter same material as process head except carbon steel shall use 316 SS 1bReference head available w ith Dual Head Gage models only. In-Line Gage models are supplied w ith Process Head only.Except Carbon Steel Heads shall use 316SS Vent/Drain & Plugs and or 1/2" adaptersModel Selection GuideModel Selection Guides are subject to change and are inserted into the specifications as guidance only.STG700 Smart Pressure Transmitter 15REVERSED 90°/STANDARD SELECTION 2 SELECTION 3STG79SSTG77S, STG78SSTG73S,STG74SSTG775STG735,STG745HH HTABLE IIMeter Body & Connection OrientationStandardHigh Side Left, Ref Side Right 2 / Std Head Orientation1*****ReversedRef Side Left, High Side Right22**90/StandardHigh Side Left, Ref Side Right 2 / 900 Head Rotation 3h hTABLE III 0*****A*****B****p C *****D *****E *****F *****G *****I *****J *****K*****TABLE IV ConnectionLightning Protection1/2 NPT None A _ _*****M20None B _ _*****1/2 NPT Yes C _ _*****M20Yes D _ _*****1/2 NPT None E _ _*****M20None F _ _*****1/2 NPT Yes G _ _*****M20YesH _ _*****_ H _*****IndicatorLanguagesNone None _ _ 0*****NoneNone _ _ A *****Standard(w/Internal Zero,Span&Configbuttons)EN, RU_ _ S*****Standard(w/Internal Zero,Span&Configbuttons)EN, RU_ _ T*****TABLE V1 _ _*****Write ProtectFail Mode Disabled High> 21.0mAdc Honeywell Std (3.8 - 20.8 mAdc)_ 1 _*****Disabled Low< 3.6mAdc Honeywell Std (3.8 - 20.8 mAdc)_ 2 _*****EnabledHigh> 21.0mAdc Honeywell Std (3.8 - 20.8 mAdc)_ 3 _*****Enabled Low< 3.6mAdc Honeywell Std (3.8 - 20.8 mAdc)_ 4 _*****Factory Standard_ _ S *****Custom Configuration (Unit Data Required from customer)_ _ C*****2 Left side/Right side as view ed from the customer connection perspective3 NAMUR Output Limits are configurable by customer 4P rocess connections w ill vary on In-Line ModelsSELECTION 14STANDARD Head/ConnectOrientationAGENCY APPROVALSNo Approvals RequiredApprovalsCCoE Explosion proof, Intrinsically Safe & Non-incendive UATR Flameproof, Intrinsically Safe & DustproofIECEx Explosion proof, Intrinsically Safe & Non-incendive <FM> Explosion proof, Intrinsically Safe, Non-incendive, & Dustproof CSA Explosion proof, Intrinsically Safe, Non-incendive, & Dustproof ATEX Explosion proof, Intrinsically Safe & Non-incendive SAEx Explosion proof, Intrinsically Safe & Non-incendive INMETRO Explosion proof, Intrinsically Safe & Non-incendive NEPSI Explosion proof, Intrinsically Safe & Non-incendiveEAC-Customs Union(Russia,Belarus and Kazakhstan)EX Approval Flameproof,Intrinsically Safe TRANSMITTER ELECTRONICS SELECTIONSa. Electronic Housing Material & Connection TypeMaterialPolyester Powder Coated Aluminum Polyester Powder Coated Aluminum Polyester Powder Coated Aluminum Polyester Powder Coated Aluminum 316 Stainless Steel (Grade CF8M)316 Stainless Steel (Grade CF8M)316 Stainless Steel (Grade CF8M)316 Stainless Steel (Grade CF8M)b. Output/ ProtocolAnalog OutputDigital Protocol4-20mA dcHART Protocolc. Customer Interface SelectionsE xt Zero,Span & Config ButtonsNoneYes (Zero/Span Only)NoneYesCONFIGURATION SELECTIONSa. Application Software DiagnosticsStandard Diagnosticsb. Output Limit, Failsafe & Write Protect Settings High & Low Output Limits3General Configurationc. General Configuration16 STG700 Smart Pressure Transmitter⁵The PM option is available on all Smartline Pressure Transmitter process wetted parts such as process heads, flanges, bushings and ventplugs except plated carbon steel process heads and flanges. PM option information is also available on diaphragms except STG and STA in-line construction pressure transmitters.For more informationTo learn more about SmartLine Transmitters, visit Or contact your Honeywell Account ManagerProcess Solutions Honeywell1250 W Sam Houston Pkwy S Houston, TX 77042Honeywell Control Systems LtdHoneywell House, Skimped Hill Lane Bracknell, England, RG12 1EB34-ST-03-122 Jan 20212021 Honeywell International Inc.Shanghai City Centre, 100 Jungi Road Shanghai, China 20061Sales and ServiceFor application assistance, current specifications, ordering, pricing, and name of the nearest Authorized Distributor, contact one of the offices below.ASIA PACIFICHoneywell Process Solutions, Phone: + 800 12026455 or +44 (0) 1202645583 (TAC) hfs-tac-*********************AustraliaHoneywell LimitedPhone: +(61) 7-3846 1255 FAX: +(61) 7-3840 6481 Toll Free 1300-36-39-36 Toll Free Fax: 1300-36-04-70China – PRC - Shanghai Honeywell China Inc.Phone: (86-21) 5257-4568 Fax: (86-21) 6237-2826SingaporeHoneywell Pte Ltd.Phone: +(65) 6580 3278 Fax: +(65) 6445-3033South KoreaHoneywell Korea Co Ltd Phone: +(822) 799 6114 Fax: +(822) 792 9015EMEAHoneywell Process Solutions, Phone: + 800 12026455 or +44 (0) 1202645583Email: (Sales)*************************** or (TAC)*****************************WebKnowledge Base search engine http://bit.ly/2N5VldiAMERICASHoneywell Process Solutions, Phone: (TAC) (800) 423-9883 or (215) 641-3610(Sales) 1-800-343-0228Email: (Sales)*************************** or (TAC)*****************************WebKnowledge Base search engine http://bit.ly/2N5VldiSpecifications are subject to change without notice.。

伊士达高Tg、低CTE、多功能填充环氧树脂和酚醛固化层压板和预浸料IT-180ABS IT-180A

IT-180ABS/IT-180ATCHigh Tg, Low CTE, Multifunctional Filled Epoxy Resin and Phenolic-Cured Laminate & PrepregIT-180A is an advanced high Tg (175℃ by DSC) multifunctional filled epoxy with low CTE, high thermal reliability and CAF resistance. It’s design for high layer PCB and can pass 260℃ Lead free assembly and sequential lamination process.Key Features =============================== Advanced High Tg Resin TechnologyIndustrial standard material with high Tg (175℃ by DSC) multifunctional filled epoxy resin and excellent thermal reliability.Lead-Free Assembly CompatibleRoHS compliant and suitable for high thermal reliability needs, and Lead free assemblies with a maximum reflow temperature of 260℃. Friendly Processing and CAF ResistanceFriendly PCB process like high Tg FR4. Users can short the learning curve when using this material.CAF ResistanceLow thermal expansion coefficient (CTE) helps to excellent thermal reliability and CAF resistance providing long-term reliability for industrial boards and automobile application.Available in Variety of ConstructionsAvailable in a various of constructions, copper weights and glass styles, including standard(HTE), RTF and VLP copper foil. ApplicationsMultilayer and High Layer PCB AutomobileBackplanesServers and Networking TelecommunicationsData StorageHeavy Copper ApplicationIndustrial ApprovalUL 94 V-0IPC-4101C Spec / 99/ 101/ 126 RoHS CompliantGlobal AvailabilityArea Address Contact e-mail TELTaiwan 22,Kung Yen 1st Rd. Ping Chen Industry Zone. Ping Chen,Taoyuan, Taiwan, R.O.C.Sales: *************.twTechnician: *****************.tw886-3-4152345 #3168886-3-4152345 #5300East China Chun Hui Rd., Xishan Economic Development Zone,Wuxi City, Jiangsu Province, ChinaSales : ****************Technician: *********************86-510-8223-5888 #516886-510-8223-5888 #3000South China168, Dongfang Road, Nanfang Industrial Park, BeiceVillage, Humen Town, Dongguan City, Guangdong Province, China Sales: ***********.cnTechnician : ***************.cn86-769-88623268 #32086-769-88623268 #550Japan No.2, Huafang Rd, Yonghe Economic Zone, Economic andTechnological Development Zone, Guangzhou,Guangdong Province, ChinaSales: ****************.cnTechnician : *****************.tw86-20-6286-8088 #8027886-3-4152345 #5388USA Tapco Circuit Supply1225 Greenbriar Drive, Suite AAddison, IL 60101, USASales: *******************************Technician : ********************************1-614-937-52051-310-699-8028Europe ITEQ Europe,Via L. Pergher, 16 38121 Trento, Italy Sales: ********************Technician : *********************39-0461-82052639-0461-820526REV 06-12ITEQ Laminate/ Prepreg : IT-180ATC / IT-180ABS IPC-4101C Spec / 99 / 101 / 126LAMINATE( IT-180ATC)Thickness<0.50 mm[0.0197 in] Thickness≧0.50 mm[0.0197 in] Units T est MethodPropertyTypical Value Spec Typical Value SpecMetric(English)IPC-TM-650(or as noted)Peel Strength, minimumA. Low profile copper foil and very low profile copperfoil - all copper weights > 17µm [0.669 mil]B. Standard profile copper foil1.After Thermal Stress2.At 125°C [257 F]3.After Process Solutions 0.88 (5.0)1.23 (7.0)1.05 (6.0)1.05 (6.0)0.70 (4.00)0.80 (4.57)0.70 (4.00)0.55 (3.14)0.88 (5.0)1.40 (8.0)1.23 (7.0)1.23 (7.0)0.70 (4.00)1.05 (6.00)0.70 (4.00)0.80 (4.57)N/mm(lb/inch)2.4.82.4.8.22.4.8.3Volume Resistivity, minimumA. C-96/35/90B. After moisture resistanceC. At elevated temperature E-24/125 3.0x1010--5.0x1010106--103--3.0x10101.0x1010--104103MΩ-cm 2.5.17.1Surface Resistivity, minimumA. C-96/35/90B. After moisture resistanceC. At elevated temperature E-24/125 3.0x1010--4.0x1010104--103--3.0x10104.0x1010--104103MΩ 2.5.17.1Moisture Absorption, maximum -- -- 0.12 0.8 % 2.6.2.1 Dielectric Breakdown, minimum -- -- 60 40 kV 2.5.6 Permittivity (Dk, 50% resin content)(Laminate & Laminated Prepreg)A. 1MHzB. 1GHzC. 2GHzD. 5GHzE. 10GHz 4.44.44.24.14.05.44.44.44.34.14.15.4 --2.5.5.92.5.5.13Loss Tangent (Df, 50% resin content) (Laminate & Laminated Prepreg)A. 1MHzB. 1GHzC. 2GHzD. 5GHzE. 10GHz 0.0150.0150.0150.0160.0170.0350.0140.0150.0150.0160.0160.035 --2.5.5.92.5.5.13Flexural Strength, minimumA. Length directionB. Cross direction ----------------500-530(72,500-76,850)410-440(59,450-63,800)415(60,190)345(50,140)N/mm2(lb/in2)2.4.4Arc Resistance, minimum 125 60 125 60 s 2.5.1 Thermal Stress 10 s at 288°C [550.4F],minimumA. UnetchedB. Etched PassPassPass VisualPass VisualPassPassPass VisualPass VisualRating 2.4.13.1Electric Strength, minimum(Laminate & Laminated Prepreg)45 30 -- -- kV/mm 2.5.6.2 Flammability,(Laminate & Laminated Prepreg)V-0 V-0 V-0 V-0 Rating UL94 Glass Transition Temperature(DSC) 175 170 minimum 175 170 minimum ˚C 2.4.25Decomposition Temperature-- -- 345 340 minimum ˚C2.4.24.6 (5% wt loss)X/Y Axis CTE (40℃ to 125℃) -- -- 10-13 -- PPM/˚C 2.4.24 Z-Axis CTEA. Alpha 1B. Alpha 2C. 50 to 260 Degrees C ------------452102.760 maximum300 maximum3.0 maximumPPM/˚CPPM/˚C%2.4.24Thermal ResistanceA. T260B. T288 -------->60>3030 minimum15 minimumMinutesMinutes2.4.24.1CAF Resistance -- -- Pass AABUS Pass/Fail 2.6.25The above data and fabrication guide provide designers and PCB shop for their reference. We believe that these information are accurate, however, the data may vary depend on the test methods and specification used. The actual sales of the product should be according to specification in the agreement between ITEQ and its customer. ITEQ reserves the right to revise its data at any time without notice and maintain the best information available to users.REV 06-12。

Design and Development of Hybrid Supercapacitors

Design and Development of HybridSupercapacitorsIn recent years, there has been a growing interest in the development of hybrid supercapacitors, which combine the high energy density of batteries and the high power density of capacitors. These devices have the potential to revolutionize energy storage and power delivery systems, with applications ranging from consumer electronics to electric vehicles and grid-scale storage systems.Design Considerations:The design of a hybrid supercapacitor involves several key considerations, including the choice of electrode materials, the construction of the device, and the optimization of its performance. The materials used for the electrodes can significantly impact the performance of the device, with a focus on maximizing both energy density and power density.Graphene, carbon nanotubes, and metal oxides are among the most promising materials for use in hybrid supercapacitors. These materials have high surface areas, allowing for increased charge storage capacity, and can also exhibit excellent electrochemical stability and cycling efficiency.In addition to electrode materials, the configuration of the device is also critical. The most commonly used configurations include asymmetric and symmetric designs. Asymmetric designs, which consist of two electrodes with different charge storage mechanisms, can offer higher energy density. Symmetric designs, where both electrodes have similar charge storage mechanisms, offer higher power density.Performance Optimization:Once the materials and configuration are selected, the performance of the device can be optimized through various techniques. For example, the use of electrode coatings andadditives can improve the electrochemical stability and charge storage capacity of the device.In addition, the electrolyte used in the device can also affect performance. Traditional electrolytes, such as aqueous and organic solvents, suffer from various limitations such as low voltage windows, limited operating temperatures, and poor stability. However, the development of ionic liquids and solid-state electrolytes has opened up new possibilities for high-performance hybrid supercapacitors.Application:Hybrid supercapacitors have enormous potential for a wide range of applications, from portable electronics to electric vehicles and renewable energy systems. These devices can provide high power density for quick charging and discharging, and also offer high energy density for extended use.For example, in portable electronics, hybrid supercapacitors could replace conventional batteries, providing longer operating times in smaller devices. In electric vehicles, hybrid supercapacitors could provide instant, high power delivery for acceleration and braking, while also extending the range of the vehicle.Conclusion:Hybrid supercapacitors are a promising technology that could transform energy storage and power delivery systems. Their unique combination of high energy density and high power density offers many opportunities for advances in portable electronics, electric vehicles, and renewable energy systems. While there are still many challenges to overcome in their development and commercialization, the potential benefits make them a technology worth pursuing.。

Nippon Electric Glass Develops Highly Efficient UV-Blocking Coated Glass for Use in Store Lighting

April 13, 2009 Nippon Electric Glass Co., Ltd.Nippon Electric Glass Develops Highly Efficient UV-Blocking Coated Glass for Use in Store LightingNippon Electric Glass Co., Ltd. (head office: Otsu, Shiga, Japan; President: Yuzo Izutsu) has successfully developed highly efficient UV (Ultraviolet)-blocking coated glass that can be utilized in large sizes. The glass is expected to be used for lighting in locations such as clothing stores. During the manufacturing process, glass is coated with special multilayer film. By placing this coated glass in front of a light source, it is possible to block UV light effectively. Since 2003, Nippon Electric Glass (NEG) has been conducting the development, manufacture, and sale of various kinds of special multilayer films created using a sputtering technique. NEG has now succeeded in developing a product based on this technique. The multilayer film can be used to form UV-blocking coated glass in sizes up to 600 x 400 mm, which is the largest* size available in the industry.*Based on NEG study＜Features＞ ■ Application Lights used in stores such as high-pressure mercury lamps emit not only visible light but also large amounts of UV light. When exposed to high-intensity light for a prolonged period, the colors of clothes will fade or discoloration will take place. It is possible to block UV light effectively without changing the transmitted colors of visible light by placing NEG’s highly efficient coated glass in front of light sources such as mercury lamps. ■ Thermal resistance The coated glass does not experience any deterioration in multilayer film, and it maintains its optical properties even at the ambient temperature of 500℃. ■ Versatility (ability to meet specific needs) The substrate glass below the multilayer film can be chosen freely in line with intended use, usage environment, and other requirements. The UV-blocking coated glass will be exhibited at the NEG booth at the 1st LED/OLED Lighting Technology Expo (LIGHTING JAPAN), which will be held at Tokyo Big Sight from April 15 to 17, 2009.【REFERENCE MATERIAL】 Comparison of Transmittance of UV-Blocking Glass100 90 80 70 Transmittance (%) 60 50 40 30 20 10 0 300UV lightNEG's UV-blocking coated glass UV-blocking glass of other manufacturer350400450500 550 Wavelength (nm)600650700UV-blocking coated glass。

钛材料六级英语

钛材料六级英语Titanium Materials: A Versatile and Remarkable SubstanceTitanium is a remarkable element that has captured the attention of scientists, engineers, and industries worldwide. This lightweight yet incredibly strong metal possesses a unique blend of properties that make it an invaluable material in a wide range of applications. From aerospace engineering to medical implants, the versatility of titanium continues to revolutionize various sectors, driving innovation and progress.At the heart of titanium's allure lies its impressive strength-to-weight ratio. Titanium is approximately 45% lighter than steel, yet it is just as strong, if not stronger, in many applications. This exceptional strength-to-weight ratio makes titanium an ideal choice for applications where weight is a critical factor, such as in the aerospace industry. Aircraft and spacecraft components made from titanium offer enhanced fuel efficiency, improved payload capacity, and increased maneuverability, all while maintaining the necessary structural integrity.In addition to its remarkable strength, titanium also exhibits excellentcorrosion resistance. The formation of a thin, stable oxide layer on the surface of titanium provides a natural barrier against corrosion, making it highly resistant to a wide range of chemical environments. This property is particularly valuable in marine applications, where titanium components can withstand the harsh saltwater environment without succumbing to the effects of corrosion. Similarly, in the chemical processing industry, titanium equipment and piping are often employed to handle corrosive substances, ensuring reliable and long-lasting performance.Beyond its mechanical and corrosion-resistant properties, titanium is also known for its exceptional biocompatibility. This characteristic allows titanium to be used extensively in medical and dental applications, such as orthopedic implants, dental implants, and surgical instruments. When implanted in the human body, titanium exhibits a remarkable ability to integrate with bone tissue, facilitating a strong and durable bond. This integration, known as osseointegration, is crucial for the long-term success of medical implants, ensuring a secure and stable interface between the implant and the surrounding bone.The remarkable properties of titanium have also found applications in the sports and leisure industries. Titanium's lightweight and corrosion-resistant nature make it an ideal material for sports equipment, such as golf clubs, bicycle frames, and various outdoorgear. The high strength-to-weight ratio of titanium allows for the creation of durable and lightweight products that enhance performance and user experience.In the realm of consumer electronics, titanium has also made its mark. Smartphones, laptops, and other electronic devices often incorporate titanium components, such as casings or structural elements, to provide enhanced protection and durability. The scratch-resistant nature of titanium helps maintain the pristine appearance of these devices, even with extended use.The versatility of titanium extends beyond its physical properties. This remarkable metal is also prized for its unique aesthetic qualities. The natural silvery-gray hue of titanium, combined with its ability to be anodized in a range of vibrant colors, makes it a popular choice for decorative and jewelry applications. Titanium's sleek and modern appearance has made it a favorite among designers and fashion enthusiasts, further expanding its reach in the consumer market.As the demand for advanced materials continues to grow, the importance of titanium in various industries cannot be overstated. Researchers and engineers are constantly exploring new ways to leverage the unique properties of titanium, leading to the development of innovative applications and products. From the latest aerospace advancements to groundbreaking medicalbreakthroughs, titanium remains at the forefront of technological progress, shaping the world we live in.In conclusion, titanium is a remarkable material that has captured the attention of industries and individuals alike. Its exceptional strength-to-weight ratio, corrosion resistance, biocompatibility, and aesthetic appeal have made it an indispensable resource in a wide range of applications. As the world continues to evolve, the importance of titanium is only expected to grow, as it continues to push the boundaries of what is possible and pave the way for a more advanced and sustainable future.。

sandwich-like,st...

S andwich-Like, Stacked Ultrathin Titanate Nanosheets for Ultrafast Lithium StorageJ iehua L iu ,J unN anomaterials in architecture for green energy conversion and/or storage provide one of the most desirable approaches to alle-viate environmental and energy issues.increasing interest in developing high-power anode materials,which can match with the state-of-the-art high-power cathodematerials, for next generation high-performance rechargeableLi-ion batteries. [5–7]Titanium dioxide is regarded as one of theideal candidates for high-rate anode materials, owing not onlyto its structural characteristics and special surface activity,but also to its low cost, safety, and environmental benignity. Thelack of open channels in bulk TiOrestricts its capacity and rate capability for reversible lithiuminsertion and extraction. A reduction in the effective size andconstruction of open channels in the material are the mainstrategies currently employed to increase the rate perform-ance. [1,4]The capacity could also be improved by reducing thepath length of lithium ion migration and improving electrontransport at the surface or in the bulk of the material.With these strategies, the capacity of ultraﬁtals and nanotubes, for example, is signiﬁlower rates. However, their capacity and cycle life deterioratedramatically at higher rates.efforts have recently been made on the fabrication of anataseTiO 2nanosheets with exposed highly reactive (001) facets.These TiO 2nanosheets are shown to be an excellent host struc-ture for lithium insertion and extraction due to the presence ofexposed (001) facets and short path along the [001] direction forlithium ion diffusion.A lthough the anatase framework undergoes insigniﬁstructural distortion during lithium insertion and extraction,the rate of lithium diffusion is still limited by the narrow spaceof the host Ti–O lattice. Also, strongly caustic NaOH and cor-rosive HCl or HF are commonly used for the synthesis ofTiO 2nanomaterials. [danger in the high-temperature and high-pressure processthe as-synthesized sample consists of LTNSs with a lat-, and the magniﬁ ed image displays the layered structure with an interlamellar spacing of nm. The high-resolution (HR) TEM image (Figure 2b ) of the gray sample obtained by annealing at 350 ° C for 2 h, clearly shows that the disc-like nanostructures are formed by stacking of several ultrathin nanosheets. The single layer thickness of .4 nm is consistent with the single-unit-cell thickness along the [010] direction. Therefore, the nanosheets should be bound by (010) facets, which is also revealed by the 2D lattice fringes observed via HRTEM (Figure S1, Supporting Information). The exposed (010) facets are considered the ideal facet, possessing empty zigzag channels with large Ti–Ti distances for lithiumhe layered structure of the as-synthesized sample was also observed by powder X-ray diffraction (XRD) analysis (Figure 2c ). from the as-synthesized ned multilamellar structure with an interlayer spacing of 10.41 Å, which is consistent with the result from the TEM analysis. The peak intensity decreases sig-cantly when the annealing temperature is increased from , due to the carbonization of the intercalated organic components in the LTNSs. After calcination at 350 °C , the ordered LTNSs are superseded by the disordered ones. At phase becomes pronouncedF igure 1. T he proposed formation mechanism of CTNS with a sandwich-like multilamellar structureEM images of the as-synthesized LTNSs (a) and the CTNSs obtained after annealing at 350 ° C for 2 h (b). XRD patterns of the samplesannealed at different temperatures (100, 200, 250, 300, and 350 ° C ) (c) and elemental mapping of CTNSs (d). The insets in (a) and (b) are the mag- ed images of the corresponding samples.titanate and organic layers. This provides strong evidence for the formation of nanocarbons. Therefore, it can be concludedthat the ﬁnal structure is the CTNSs, based on the analyses from the XRD pattern, indicating partial col-lapse of LTNS to form ultrathin anatase TiO nanosheets. Further increasing the annealing temperature to 400 removal of the nanocarbon components and formation of pure anatase TiO (JCPDS no. 21 – 1272; Figure S2, Supporting Information).T he presence of C, O, and Ti was detected by elemental mapping and energy-dispersive X-ray (EDX) analysis of the sample as shown in Figure 2d . The uniformly dispersed carbon component in the CTNSs is derived by in situ carbonization of the residual organic species that stabilize the LTNSs. The corollary is also supported by thermogravimetric analysis (TGA; Figure S3, Supporting Information). The TGA curve of the LTNSs shows a total weight loss of ca. 25% which was recorded from room temperature to 500 which the organic components have been removed completely. Apparently, the sample annealed at 350 ° C still contains about 5.6%nanocarbons by weight, compared with the sample annealed at 200 carbon pillars not only strengthen the stacked ultrathin layers and prevent complete con-densation, but also offer ample space for Li ion diffusion.T he samples were further characterized by N 2adsorption–desorption isotherms and corresponding pore size distributions (Figure S4 and S5, Supporting Information). It is interesting to observe the abrupt increase of the pore fraction with size above ≈ 1 nm in the as-synthesized LTNSs. This observation might berelated to the uniform stacked structure. The surface area and total pore volume of the CTNSs are 109 m respectively. Notably, the CTNSs possess smaller total pore volume but larger pore diameter compared with LTNSs because of the carbonization of organic components. In addition, Fou-rier transform infrared (FTIR) and Raman spectra further sup-port our analysis of carbonization. The FTIR spectra (Figure S6, Supporting Information) shows the absorption bands of C–H and C–OH bonds in CTNSs sample are almost ﬂcrystallinity of the carbon in Raman spectra is indiscernible (Figure S7, Supporting Information). It may be due to the F igure 3. E lectrochemical measurements of the CTNSs. a) The ﬁ rst-cycle charge–discharge voltage proﬁ les at different current rates of 1 C, 2 C, 5 C, and 10 C. b) Representative cyclicvoltammograms at a scan rate of 1 mV s− 1 . c) Cycling performance of the CTNSs cycled at a constant current drain of 10 C and the corresponding Coulombic efﬁ ciency and d) cycling performance at different charge–discharge rates (2–50 C).igure 4.a) TiO 2nanosheets obtained in the IL solution without Li +ion;b) Charge–discharge curves of the TiO 2nanosheets annealed at 350 °C cycled at a constant current drain of 5 C.the promising use of this material in high-power lithium-ion batteries.E xperimental SectionS ynthesis of Ionic Liquid: The synthesis of IL was carried out in a 500-mL round-bottomed ﬂask, which was immersed in an ice-bath. Acetic acid (60.0 g, 1.0 mol) was added dropwise into the N,N dimethylethanolamine (98 g, 1.1 mol). After vigorous stirring for 2 h, the obtained protic IL was directly used to prepare the titanate material.P reparation of Samples: In a typical experiment, 11 g of tetrabutylC haracterization: XRD measurement was performed with a D8 diffractometer with Cu-KR radiation (was carried out with JEOL JEM-1400 and JEOL 2100F. Ndesorption isotherms were conducted at 77 K on a Micromeritics Tristar 3000 analyzer. The BET surface areas and pore-size distribution curves were calculated using adsorption data. Thermogravimetric analysis was determined using a thermal gravity analyzer (TGA) at a temperature rise rate of 10 °C min −1from room temperature to 600air ﬂ ow. For 13C and 1Hmeasurements, a JNM-ECA400 spectrometer was used at 100.5 and 400.0 MHz, respectively. FTIR spectra were recorded on a Shimazu IR Prestige-21 FT-IR Spectrometer. Raman spectra were collected on an R-3000HR spectrometer using a red LED laser (E lectrochemical Measurementsperformed using two-electrode Swagelok-type cells with lithium serving as both the counter and reference electrodes at room temperature. The working electrode was composed of 70 wt% of the active material, 20 wt% of conductivity agent (carbon black, Super-P-Li), and 10 wt% of binder (polyvinylidene diﬂ(CTNS) was about 1–2 mg on each electrode and the ﬁ20 μm in thickness. The electrolyte used was 1mixture of ethylene carbonate and diethyl carbonate. Cell assembly was carried out in an argon-ﬁ1 mV s −1) was performed using an electrochemical workstation (CHI 660C). Galvanostatic charge–discharge cycling was conducted using a battery tester (NEWAER) with a voltage window of 1–3 V at different current rates of 1 C,2 C, 5 C, 10 C, 20 C, 30 C, and 50 C, where 1 C 170 mA g −1.S upporting InformationS upporting Information is available from the Wiley Online Library or from the author.A cknowledgementsT he authors acknowledge ﬁUniversity (RG54/07) and the Ministry of Education (ARC24/07, T206B1218RS; AcRF Tier-1, RG63/08, M52120096), Singapore.[ 1]A. S. A rico ,P. B ruceN at. Mater.2005,4[ 2]A. Y amada ,H. K oizumiM. Y onemura ,T. N。

High Performance Fiber

c 2005Wiley-VCH Verlag GmbH&Co.KGaA,Weinheim10.1002/14356007.a13001High-Performance Fibers1High-Performance FibersHiroshi Mera,Teijin Limited,Osaka,Japan Tadahiko Takata,Teijin Limited,Osaka,Japan1.Deﬁnition and Classiﬁcation (1)2.Heat-Resistant Fibers (4)2.1.Introduction (4)2.2.Solution-Spun Heat-ResistantFibers (5)2.2.1.Aramid Fibers (5)2.2.2.Polyazole and Polyimide Fibers..9 2.3.Melt-Spun Heat-Resistant Fibers11 2.3.1.Novoloid Fibers (11)2.3.2.Fibers from Engineering Plastics..113.High-Strength and High-Modulus(HS–HM)Fibers (12)3.1.Introduction..............123.2.Solution-Spun HS–HM Fibers..14 3.2.1.Para-Oriented Aramid Fibers. (14)3.2.1.1.Production (14)3.2.1.2.Properties (17)es (18)3.2.2.HS–HM Fibers from Some Aramid-Related Polymers (19)3.2.3.Polyazole and Polyimide Fibers..19 3.2.3.1.Polyazole Fibers (20)3.2.3.2.Polyimide Fibers (21)3.3.Melt-Spun HS–HM Fibers (21)4.References (23)Abbreviations used in this article:BBB poly(bisbenzimidazobenzophen-anthroline)FFﬁber–ﬁberHM high modulusHS high strengthLOI limiting oxygen indexPAI poly(amide–imide)PBI polybenzimidazolePBO poly(p-phenylenebenzobisoxazole) PBT poly(p-phenylenebenzobisthiazole) PEEK polyetherether ketonePEI polyetherimidePI polyimidePMIA poly(m-phenyleneisophthalamide) PMTA poly(m-phenyleneterephthalamide) PPIA poly(p-phenyleneisophthalamide) PPPI poly(p-phenylenepyromellitimide) PPP poly(p-phenylene)PPS poly(phenylene sulﬁde)PPTA poly(p-phenyleneterephthalamide) 1.Deﬁnition and Classiﬁcation Although a strict deﬁnition of high-performance ﬁbers does not yet exist,the term generally de-notesﬁbers that give higher values in use in a range of applications.It commonly refers to ﬁbers with some unique characteristics that dif-ferentiate them from commodityﬁbers such as nylon,polyester,and acrylicﬁbers.Synonyms are specialtyﬁbers and,in some cases,high-functionalﬁbers.High-performanceﬁbers can be classiﬁed broadly into three categories ac-cording to their applications:1)heat-resistantﬁbers,includingﬂame-retardant ones;2)high-modulus and high-strengthﬁbers;and3)otherﬁbersTractable or fusible polymers can be spun from a polymer melt(melt spinning).Polymers that can be dissolved in a suitable solvent can be spun from a solution(solution spinning). The dissolved polymer is spun into a hot gas where the solvent evaporates(dry spinning)or into a liquid coagulating bath(wet spinning) (→Fibers,3.General Production Technology).The concept of high-performanceﬁbers cov-ers not only organic but also inorganicﬁbers of carbon,alumina,and boron,which often in-clude various whiskers(→Fibers,5.Synthetic Inorganic;→Whiskers).A variety of high-performanceﬁbers can be found in composite materials(→Composite Materials).Moreover, highmodulusﬁbers from aliphatic polymers, such as polyethylene or polyoxymethylene,also belong to the class of high-performanceﬁbers2High-Performance Fibers(→Fibers,4.Synthetic Organic,Chap.4.).The classiﬁcation of high-performance ﬁbers is sum-marized in Figure1.Figure 1.Classiﬁcation of high-performance ﬁbersThe term high performance may also be ap-plied to other properties such as radiation resis-tance [11],[12]or electrical conductivity [13](→Polymers,Electrically Conducting),but a discussion of these ﬁbers is beyond the scope of this article.Here,discussion is restricted to the polymerization,ﬁber production,properties,and applications of ﬁbers obtained from wholly aromatic polymers.Table 1.Aromatic residues of meta-and para-oriented aromatic polymers[14]Wholly aromatic polymers may be classi-ﬁed as meta-or para-oriented,depending on their chemical structure and properties.Fibers from meta-oriented polymers are useful as heat-resistant ﬁbers.Para-oriented polymers are ex-pected to be useful not only as heat-resistant ﬁbers but also as high-strength (HS)or high-tenacity and high-modulus (HM)ﬁbers.Typicalexamples of aromatic residues of the two classes are given in Table 1[14].Figure 2shows the melting (softening)points of aromatic polyamides (aramids)with four components having m -or p -phenylene residues [15–18].These four components are poly(m -phenyleneisophthalamide [24938-60-1](PMIA),poly(m -phenyleneterephthalamide)[24938-63-4](PMTA),poly(p -phenyleneisophthalamide)[24938-61-2](PPIA),andpoly(p -phenyleneterephthalamide)[24938-64-5](PPTA).Fibers from PMIA,PMTA,or PPIA are heat-resistant and are classiﬁed in this article as meta-oriented according to their ﬁber properties.Meta-oriented aramid ﬁbers have a higher heat resistance than commodity ﬁbers such as polyester or polyacrylonitrile ﬁbers,as well as favorable physical and mechanical properties for clothing or textile use.The PMTA ﬁbers have a higher heat resistance than PMIA ﬁbers,but their physical and mechanical properties are similar;thus,they are deﬁned as meta-oriented.Heat-resistant,high-modulus PPTA ﬁbers are deﬁned as para-oriented.Some ambigui-ties inevitably arise in copolymers containing more than 50mol %of para-substituted residues.Among the aramids shown in Figure 2,optical anisotropy in concentrated sulfuric acid is shown by polymers in which more than ca.75mol %ofHigh-Performance Fibers3the total phenylene residues are para-oriented.Such polymers can give high-modulus ﬁbers[18].Figure 2.Melting points (◦C)of aramids [16]PMIA =poly(m -phenyleneisophthalamide);PMTA =poly(m -phenyleneterepthalamide);PPIA =poly(p -phenyleneisophthalamide);PPTA =poly(p -phenyleneterephthalamide)Liquid crystalline polymers are divided into three classes based on their chemical structures:backbone,side-chain,and mixed-conﬁguration types.Predictions and explanations of the struc-tural characteristics of low molecular mass com-pounds expressed as liquid crystallinity have been investigated in detail.These predictions are also applicable to liquid crystalline polymers.Important factors affecting liquid crystallinity are pressure,density,temperature,and chemical structure (degree of polymerization and proper-ties of the repeating units,i.e.,length,shape,in-trachain rotational energy,dipole moment,site –site polarizability)[19].Polymer concentration is an important factor in lyotropic liquid crys-talline polymers.Most meta-oriented ﬁbers are heat-resistant;they are regarded as the ﬁrst generation of high-performance ﬁbers.Research and development on these ﬁbers was spurred by the strong demand for heat-resistant and ﬂame-retardant materials for space programs or industrial use after World War II.Many attempts were made to commer-cialize heat-resistant ﬁbers,but only a few were successful at that time.Para-oriented ﬁbers are considered the sec-ond generation of high-performance ﬁbers;they are composed mainly of para-substituted residues,instead of the meta-substituted residues of the ﬁrst generation.Table 2.Examples of high-performance ﬁbers PolymerTrade name or developmental nameMeta-oriented ﬁbersPara-oriented ﬁbers AramidNomex (HT-1;Du Pont)Kevlar (Fiber-B,PRD-49,HT-4;Du Pont)Teijinconex (Teijin)Technora (HM-50;Teijin)Fenilon (former Soviet Union)Terlon (former Soviet Union)Twaron (Arenka;Akzo)Apyeil (Unitika)Vniivlon (former Soviet Union)KM-21(Kuraray –Mitsui Toatsu)Engineering polymersPoly(phenylene sulﬁde)PPS (Phillips)Polyetherether ketonePEEK (ICI)Polyether-imide ULTEM (General Electric)PI 2080/P8,4(Dow –Lenzing)Novoloid (cross-linked Kynol (Gun-ei Chem.–Nippon phenolic resin)and American Kynols)Polyamidehydrazide X-500(Monsanto)X-715(Monsanto)Polyarylate Vectran (Kuraray –Celanese)Econol (Sumitomo Chemical –Unitika)Polyazole Celazole (Celanese)PBT,PBO (Stanford ResearchInstitute International –Dow)Poly(amide –imide)Kermel (Rhˆo ne –Poulenc)Polyimide Arimide (formerSoviet Union)Ladderpolymer BBB (J.E.Mark –Celanese)Chelatepolymer Enkatherm (Akzo)Compared to meta-oriented ﬁbers,highly so-phisticated polymerization and production tech-niques are needed for the para-oriented type to overcome difﬁculties caused by their rigid molecular structure.Du Pont initiated the sec-ond generation with Kevlar,a successor to the4High-Performance Fibersﬁrst-generation Nomex.A tremendous amount of competitive research and development work has been undertaken in the industrialized coun-tries.Despite these efforts,someﬁbers have had to be withdrawn at the developmental stage. Nevertheless,commercial exploitation has con-tinued;HS and HMﬁbers have been intro-duced in conjunction with the development of composite materials(→Composite Materials, Chap.4.1.2.;→Reinforced Plastics).Fibers from engineering polymers such as poly(phenylene sulﬁde),polyetherether ketone, and polyetherimide are attracting attention as a way toﬁll the gap between commodityﬁbers andﬁrst-generation heat-resistantﬁbers.The improved ratio of performance to cost is also at-tractive,as are the unique characteristics of this class ofﬁbers;although they are melt-spinnable, they still have good thermal,mechanical,heat-adhesive,and chemical resistance properties.Some typical high-performanceﬁbers,in-cluding those that have not been commercial-ized,are listed in Table2.2.Heat-Resistant Fibers2.1.IntroductionPolymers used for heat-resistantﬁbers are based on a comparatively simple concept of molecular design.The melting point(T m)of polymers can be described by the formulaT m=∆H/∆Swhere∆H and∆S are the enthalpy and en-tropy of fusion,respectively.The enthalpy of fusion can usually be in-creased by introducing symmetrical,rigid,or planar structures into the molecular backbone. The entropy of fusion can be decreased by in-troducing planar structures or polar linkages, such as amide bonds,into the molecular chain. For example,aramids have high melting points and high glass transition temperatures owing to strong intermolecular interactions between the aromatic residues and the amide linkages in their chain structures.In addition,the chemi-cal structure of most wholly aromatic polymers makes them stable against moisture and oxida-tion.This conforms with the properties of cross-linked polymers(e.g.,novoloid polymers)be-cause the polymers are expected to have a rather small entropy of fusion in the softening stage even though they do not exhibit a well-deﬁned melting point.New technologies are required for the poly-merization and spinning of heat-resistantﬁbers because the processing qualities of heat-resistant polymers are usually not as good as those of commodityﬁbers.Most of the problems are caused by a relatively high melting point and poor solubility.These problems can be over-come by using the solution polymerization–spinning method with polar solvents.Alterna-tive approaches are cross-linking or additional solid-phase polymerization after melt spinning. For melt-spunﬁbers,sophisticatedﬁber produc-tion technologies have had to be developed,for example,increasing the degree of polymeriza-tion or improving the stabilizer,spinning equip-ment,and spinning conditions.Solution spinning,melt spinning,and other aspects ofﬁber production discussed in this article are described in detail elsewhere(see →Fibers,3.General Production Technology).2.2.Solution-Spun Heat-Resistant Fibers2.2.1.Aramid FibersPolymerization and bina-tions of aromatic diamines and aromatic dicar-boxylic acids yield a variety of aramids,many of which are processed intoﬁbers.Excellent review articles are available on the thermal and physical properties of theseﬁbers[1],[20].This section describes mainly meta-oriented aramid ﬁbers of industrial importance.Since Du Pont commercialized Nomex in 1967,various combinations of processes have been proposed for the production of aramid ﬁbers based on poly(m-phenyleneisophthal-amide)(PMIA)(Fig.3).The polymer is pre-pared by low-temperature solution polymeriza-tion or interfacial polymerization according to the following reaction[21]:High-Performance Fibers5Figure3.Production processes for PMIAﬁbersIn both the solution and the interfacial meth-ods,the following factors are important for the preparation of a high molecular mass polymer: use of high-purity monomers,stoichiometric balance of the two parent monomers,and min-imization of the water content of the polymer-ization system.A small amount of a monofunc-tional compound such as aniline is generally used to control the degree of polymerization (Fig.4)[22].Polar amide solvents such as N,N-di-methylacetamide[127-19-5]are used in low-temperature solution polymerization[23].These solvents are not only superior with regard to sol-ubility but are also effective in activating elec-trophilic reagents.They act as acceptors of by-product HCl,as well.Spin dope is obtained by neutralizing byproduct HCl with calcium hy-droxide(Fig.3,route A).This solution coagu-lates poorly in wet spinning because of the high content of calcium chloride and water.Accord-ingly,dry spinning is adopted in the Nomex pro-cess;residual calcium chloride and solvent are removed subsequently by water and heat treat-ment,respectively[24].Interfacial polymerization is carried out at the interface between a cyclic ether solvent,such as tetrahydrofuran[109-99-9],and an aqueous alkaline carbonate solution as an acid accep-tor(Fig.3,route B)[25].Polymers produced by the interfacial method contain a larger pro-portion of low molecular mass oligomers than those obtained by the solution method;this de-creases the thermal stability of theﬁbers.In an improved interfacial method used by Tei-jin[26],preliminary oligomerization is carried out in tetrahydrofuran,and the resultant stoi-chiometric mixtures are subjected to interfacial polymerization(Fig.3,route C)[27].Subse-quently,the powdery polymer is dissolved in N-methylpyrrolidone at a concentration of20–23wt%[28],and the resultant spin dope is wet-spun in aqueous calcium chloride solution [29].The as-spunﬁber is preoriented and sub-sequently hot-drawn at200–350◦C.Two modiﬁed processes have been proposed to overcome the poor coagulation of spin dope in the wet-spinning method.One utilizes a co-agulant that gives void-free,as-spunﬁber with high transparency[30];The other involves re-ducing the calcium chloride content in the spin dope by removing hydrogen chloride in the form of ammonium chloride,a byproduct of the pre-6High-Performance Fiberspolymerization step (Fig.3,route D)[23],[31],[32].Figure 4.Control of the molecular mass of PMIA by addi-tion of aniline [22]Addition of aniline gives a wider molar ratio range for con-trolling η(i.e.,molecular mass)within the limits 1.7–1.8(compare a 0→b 0and a 1→a 1).P 0and P 1denote the max-imum molecular mass with and without aniline,respectively.∗In aramid technology,molecular mass is usually expressed as a logarithmic viscosity number ln (η/η0)/c (η=viscosity coefﬁcient of solution,η0=viscosity coefﬁcient of solvent,c =polymer concentration,dL/g).Poly(m -phenyleneisophthalamide)is fusible in an inert atmosphere,although decomposition proceeds simultaneously in the molten state.Tei-jin has proposed a melt process for producing ﬁlaments by using a special spinneret,which has only its exit surface heated to avoid thermal decomposition [33].The Mitsui Toatsu and Kuraray group has de-veloped a new aramid ﬁber KM-21.Because the ﬁber is produced by polymerizing an aromatic isocyanate and aromatic carboxylic monomers,it differs from the foregoing PMIA ﬁbers with respect to its chemical structure,production,and properties.However,its exact chemical structure and production method have not been made pub-lic[34].Fiber Properties.Important properties of meta-oriented aramid ﬁbers are summarized in Table 3.The heat resistance and ﬂame retardance of these ﬁbers are better than those of commodity textile ﬁbers.The physical properties of Teijin-conex,a typical PMIA ﬁber,follow [35]:Degree of crystallinity 35–39%Degree of orientation 90–93%Crystallite size 3.5–3.9nm Birefringence index 0.14–0.15Density1.37–1.38,g/cm 3The moisture regain of this ﬁber is about 5%under standard conditions (21◦C,65%R.H.)and 9%at 95%R.H.,which is between equiv-alent values for cotton and nylon ﬁbers.Mechanical Properties.Most of the mechan-ical properties of PMIA ﬁbers are about the same as those of commodity ﬁbers (see Table 3).How-ever,their wear resistance,both ﬂexural and fric-tional,is lower than that of nylon or polyester ﬁbers.Weatherability and Dyeability.The weather-ability of PMIA ﬁbers is not inferior to that of ny-lon ﬁber,as far as strength retention is concerned (Fig.5)[35].However,the whiteness of PMIA deteriorates because the light-induced Fries re-arrangement occursreadily.Figure 5.Weatherability of PMIA ﬁber [35]a)Nylon;b)Teijinconex (PMIA);c)PolyesterFibers from wholly aromatic polymers are,in general,highly sensitive to light exposure and poorly dyeable.Intrinsic color is a defect of wholly aromatic polymers,particularly when they are used for textile materials.Only PMIAHigh-Performance Fibers7Table 3.Physical properties of meta-oriented heat-resistant aramid ﬁbers (PMIA)PropertyTeijinconex,(Teijin)[35]Nomex,(Du Pont)[36]Fenilon Apyeil,KM-21∗(former Soviet(Unitika)(Mitsui Union)[37][38]Toatsu)[39]Regular HT type Staple Filament Staple Staple Staple staple ﬁberstaple ﬁber ﬁber ﬁberﬁberﬁber Density,g/cm 31.37–1.38 1.37–1.38 1.38 1.38 1.33–1.361.381.32Tensile strength,GPa 0.55–0.670.850.490.650.38–0.430.55–0.610.61Tensile modulus,GPa 6.95–9.9912.168.5317.069.75Elongation at break,%35–5029312224.9–35.635–4522Moisture regain,% 5.0–5.2 5.5 5.5 5.5 5.5LOI30–3230303030–3233Heat shrinkage,%4–65 2.6–4.6>18(300◦C,(300◦C,(300◦C,(400◦C,15min)15min)15min)10min)∗Composition unknown;made by polymerizing aromatic isocyanate and aromatic carboxylate monomers.is colorless and can thus be employed in dyed textiles.Methods proposed for dyeing PMIA ﬁbers in-clude the use of carriers,cationic dyes,or dope dyeing.Attempts to improve dyeability have in-volved modifying the ﬁber structure [40]and blending PMIA with other polymers [41].Most ﬁber manufacturers have their own proprietary products featuring improved dyeability or light-fastness.Figure 6.Strength retention in PMIA ﬁber exposed to dry heat [35]The limiting oxygen index (LOI)is an impor-tant measure of ﬂame retardance and represents the percent concentration of oxygen needed forself-supporting combustion.The LOI values of meta-oriented aramid ﬁbers are given in Table 3.Heat Resistance and Flame Retardance.Be-cause PMIA exhibits high crystallinity and strong intermolecular cohesion due to hydro-gen bonding,it has a high melting point and a high decomposition temperature.Accordingly,PMIA ﬁbers have better thermal properties than commodity ﬁbers.At elevated temperature,PMIA ﬁbers offer better long-term retention of mechanical properties than commodity ﬁbers;they also have good dimensional stability.In the thermogravimetric analysis curve of a PMIA ﬁber,the decomposition temperature is 400–430◦C.Mechanical properties are almost unchanged down to −35◦C,and the ﬁber is still ﬂexible with slight hardening.Teijinconex (PMIA)staple ﬁber shrinks only 1%at 250◦C (dry heat)and 5–6%up to 300◦C.Long-term heat resistance of the ﬁber at various temperatures is shown in Figure 6.Unmodiﬁed PMIA ﬁbers shrink in a high-temperature ﬂame.Improvement in dimensional stability and ﬂame retardance has been achieved by treating PMIA ﬁbers or fabrics with halo-gen,sulfur,and phosphorus compounds (e.g.,Cl 2,Br 2,molten sulfur,SOCl 2,SO 2Cl,POCl 3,POBr 3,PCl 3,PCl 5)[42]and by blending with ﬁbers that shrink less,such as Kevlar [43];some products are available in ﬂame-retardant grades.Thermal properties can be improved markedly by replacing one of the meta monomers by a para monomer as in PMTA (see Fig.2).A self-8High-Performance Fibersextinguishing PMTAﬁber has even been de-veloped[44].The KM-21ﬁber is also self-extinguishing and has a higher heat resistance than PMIAﬁbers(see Table3).Uses.Because of the excellent properties of PMIAﬁbers(e.g.,high thermal and chemical resistance,as well as radiation resistance),their end uses are growing.Typical applications fol-low.Clothing.Meta-oriented aramidﬁbers do not ignite,ﬂare,or melt and stick to the skin.This makes them suitable for heat-resistant clothing material in the following areas:1)heated furnaces:work uniforms,aluminizedcoats and pants,capes and sleeves,gloves and mitts,leggings,and spats;2)emergency services:aluminized proxim-ity suits,turnout coats and jumpsuits,sta-tion uniforms,rescue uniforms,ﬁre-ﬁghting and aviation garments,riot police uniforms, ranger uniforms,gloves,underwear,leg-gings,and spats;3)fuel handling:work uniforms,rubber coats,gloves,socks,underwear,etc.Interior Fittings.Materials from PMIA are used in aircraft interiors(for increased safety and enhancedﬂame retardance).Industrial es here includeﬁl-tration fabrics(especiallyﬁlter bags for hot stack gases);high-temperature heat insulants(espe-cially replacing asbestos);reinforcement inﬁre hoses,V-belts,and conveyor belts;threads for high-speed sewing;and cut-ﬁber reinforcement for rubber composites.Electrical Insulation.High-temperature pa-per insulation for electric motors,dynamos, transformers,and cables;braided tubing for wire insulation;and dryer belts for papermaking are among the uses of PMIAﬁbers.Miscellaneous Uses.Home ironing-board covers and kitchen gloves are also made from PMIAﬁbers.2.2.2.Polyazole and Polyimide Fibers Three types of wet-spun polyazole and poly-imideﬁbers important for industrial and military uses are discussed:1)polybenzimidazoleﬁbers(e.g.,Celazole),2)poly(amide–imide)ﬁbers(e.g.,Kermel),and3)polyimideﬁbers(e.g.,Arimide).Fiber Production.The polymer structure of the polybenzimidazole(PBI)ﬁber Celazole [25734-65-0]manufactured by Celaneseis: Production is described in detail in[45].Poly-merization is carried out in two steps.Theﬁrst step involves conventional melt polymerization to yield a low molecular mass polymer with an intrinsic viscosity of0.2–0.3dL/g.The prod-uct is porous due to the formation of gaseous byproducts such as phenol and water.In the sec-ond step,this porous prepolymer is crushed to aﬁne powder and heated gradually to380◦C to produce aﬁber-grade polymer with an intrinsic viscosity 0.75dL/g.Both steps are carried out under a nitrogen atmosphere.The polymer is powdered and dissolved in N,N-dimethylacetamide at a concentration of ca. 23wt%.Lithium chloride in N,N-dimethylacet-amide is reported to form a better solvent system for PBI than the acetamide alone.A PBIﬁber is obtained by dry spinning from aﬁltered dope,followed by drawing the as-spunﬁber under a nitrogen atmosphere.The ﬁber obtained has excellentﬂame retardance, although heat shrinkage is appreciable.The sul-fonation of imidazole residues in the PBI greatly improves its dimensional stability inﬂame-retardance tests.Kermel(Rhˆo ne–Poulenc)is an example of a poly(amide–imide)(PAI)ﬁber[46]. Polymerization is carried out in a polar amide solvent to form the precursor polymers.High-Performance Fibers9A spin dope of PAI is obtained by in situ im-idation of the precursor polymer [poly(amide –amic acid)]in solution by heating to ca.100–120◦C;N -methylpyrrolidone is used as a sol-vent.The PAI ﬁber is spun from the dope and subjected to heat treatment.In the case of polyimide (PI)ﬁber [47],spin dope containing poly(amic acid)is obtained.A precursor ﬁber is spun from the dope and then converted to PI ﬁber by heating,because PI is in-soluble in amide solvents whereas its precursor polymer is readilysoluble.In Arimide ﬁber [25036-53-7]and [25038-81-7],X is oxygen.Poly(bisbenzimidazobenzophenanthroline)[39319-28-3](BBB)ﬁber attracted the attentionof many polymer chemists and ﬁber scientists when it was reported by Marvel et al.[48].The ﬁber has excellent heat resistance,but no commercial product is known.The BBB polymer is a double-stranded lad-der polymer with a very high heat dder polymers have relatively high melting points and excellent weight retention as a func-tion of temperature.However,ladder polymers are difﬁcult to spin into ﬁbers because of their low tractability.Properties and Uses [49],[50].Properties of typical PBI,PAI,and PI ﬁbers are listed in Table 4.Polybenzimidazole ﬁber was developed in response to the needs of the U.S.Air Force to satisfy special requirements for the NASA space program.Its moisture regain is similar to that of wool,and its modulus is lower.Of ﬁbers known at present,PBI has the highest LOI value;it tends to compete against PMIA ﬁbers in its applica-tions but is more expensive.Applications should exploit its resistance to chemicals and high tem-perature;they include1)thermal-protection clothing:garments for ﬁre ﬁghters,industrial work uniforms,space and military ﬂight suits,underwear and es-cape suits,and other aerospace materials;2)high-temperature ﬁltration:high-tempera-ture ﬁlters (e.g.,ﬂue-gas ﬁlters);and3)asbestos substitute:protective gloves for high-temperature uses.The uses of meta-oriented PAI and PI ﬁbers are similar to those of the meta-oriented aramid ﬁbers.Kermel (PAI ﬁber)is used in underwear for pilots or operators of armed tanks because the resulting fabric is more supple than aramid fabrics.10High-Performance FibersTable4.Properties of heat-resistant polybenzimidazole(PBI),poly(amide–imide)(PAI),and polyimide(PI),stapleﬁbersProperty PBIﬁber(Celazole,Celanese)[49]PAIﬁber(Kermel,Rhˆo ne–Poulenc)[50]PIﬁber(Arimide,former Soviet Union)[47]234AGF235AGFDensity,g/cm3 1.4 1.34 1.34 1.41–1.43 Tensile strength,GPa0.330.470.20.63–0.7 Elongation at break,%28.523326–8Tensile modulus, G Pa 3.966.57 3.299.15–10.03Moisture regain,%153–53–5 1.0–1.5 LOI>4130–3230–32Heat shrinkage,%0.50–0.10–0.5 1.0–1.52.3.Melt-Spun Heat-Resistant Fibers 2.3.1.Novoloid Fibers(→Phenolic Resins)Fiber Production.The melt-spinning method has the advantage of eliminating the need for solvent recovery;however,melt-spun ﬁbers are less heat-resistant than solution-spun ﬁbers.Kynol[9003-55-8],a commercial no-voloidﬁber,exhibits exceptionally high heat re-sistance because cross-linking occurs after melt spinning.Kynol is produced from a novolac polymer by melt spinning[52]and subsequent cross-linking with formaldehyde[53].The as-spun novolak reacts with formaldehyde in the presence of an acid catalyst to form cross-linked networks of methylene and dimethylene etherbonds.Novoloidﬁber wasﬁrst developed by Car-borundum as a carbon-ﬁber precursor and com-mercialized in the1970s as a heat-resistant ﬁber[51].It is produced by Gun-ei Chemicals and distributed by Nippon Kynol and American Kynol[54],[55].Properties.One of the most remarkable fea-tures of novoloidﬁber is itsﬂame retardance.It generates virtually no smoke or gas.It has high LOI values and can be converted to carbonﬁbers without melting or shrinkage by heating in an in-ert atmosphere.Kynol shows good thermal stability at150◦C in air and200–250◦C in the absence of air.Its chemical stability is also excellent.Kynol has excellent heat-insulation and acoustic proper-ties.Its density is relatively low compared to other heat-resistantﬁbers.The weatherability and light stability of Kynol are moderate.Dyeability is limited be-cause of its intrinsic golden-brown color.Textile properties of Kynolﬁbers follow[56],[57]: Diameter14–33µm Density 1.27,g/cm3 Tensile strength0.15–0.20GPa Elongation at break30–60% Tensile modulus 3.3–4.4GPa Loop strength0.2–0.35GPa Knot strength0.12–0.17GPa Elastic recovery(3%elongation)92–96% Moisture regain(20◦C,65%R.H.)6%LOI30–34Uses.Novoloidﬁber is used as reinforcement in resins and rubber to improve properties such as heat resistance,electrical insulation,and di-mensional stability.Further applications are in cable material,brake material,various industrial sheets(e.g.,welders’protective sheet,work-place shielding sheet),and safety products for accident prevention.2.3.2.Fibers from Engineering PlasticsFiber Production.Progress in both poly-merization andﬁber production technologies in theﬁeld of engineering plastics has stimu-。

兰州化物所等发展出聚酰亚胺3D打印新方法及工艺装备

据媒体报道，日前，英国伦敦大学学院和美国芝加哥大学的研究人员已经发现，镁铬氧化物微粒或许是研发一种新型镁电池的关键，这种电池将比传统的锂离子电池拥有更强的蓄电能力。

此项研究发表在英国皇家化学学会杂志《纳米尺度》上。

据了解，这项研究公布了制造这种新材料的全新方法，该材料能够可逆地存储高度活跃的镁离子。

该研究团队宣称，这意味着他们向镁电池又迈出了重要一步。

迄今为止，只有极少数无机材料表现出了可逆的镁离子吸收和排除能力，这对于镁电池来说是至关重要的。

锂离子电池的限制因素之一就是它的阳极。

出于安全考虑，锂离子电池中必须使用低容量的碳棒，因为纯锂材料的阳极能够引发危险的短路甚至起火。

相比之下，镁作为阳极更加安全，因此阴极材料与镁搭配会让电池体积更小但储存能力更强。

西安交大科研人员设计出新型石墨烯夹层材料发展绿色、高效的新能源存储技术是目前新能源领域一个迫在眉睫的问题。

锂硫电池作为一种高比能二次电池，具有价格低廉、储备丰富、环境友好等特点，被誉为锂离子电池之后下一代动力电池体系的发展方向。

但锂硫电池中多硫化锂的“穿梭效应”是造成电池性能衰退的主要原因，阻碍其进一步实际应用。

近日，西安交通大学化工学院李明涛课题组设计开发了一种具有二维结构g-C3N4/石墨烯保护层的正极材料，获得了长循环寿命的锂硫电池。

其研究成果的论文——“一种二维层状g-C3N4/石墨烯复合型正极夹层增强锂硫电池循环性能研究”发表在新出版的国际著名期刊《可持续能源材料化学》（ChemSusChem）上，并入选为封面文章。

西安交大屈龙讲师为第一作者，李明涛副教授为第一通讯作者，美国橡树岭国家实验室戴胜教授为共同通讯作者。

据论文作者介绍，该工作创造性地设计了一种二维插层结构的g-C3N4/石墨烯夹层，如同在电池正负极之间构建了多层“防鲨网”，不仅能通过物理和化学双重作用阻挡多硫化物在正负极之间穿梭，还能加快Li+的扩散，从而大大提升电池的循环寿命。