一种含有活性端基的耐高温有机硅树脂制备及表征

为了适应电子器件集成度日益提高所带来的发热功率的成倍增加,对复合材料的耐温性要求越来越高,同时也要求良好的电性能和材料稳定性,以保证控制部件的可靠性.使用带有双键基团的三乙氧基硅烷进行合成反应,通过可控水解缩合反应制备液态硅树脂预聚物,使用催化剂固化交联后得到高耐温的基体树脂.通过红外表征证明了分子设计的正确性.热力学测试表明,该树脂具有优良的耐温性能.可满足国内耐高温树脂基体材料的需求,应用于航空、航天飞行器及微电子等领域的耐高温保护涂层.     

改进的固相法合成铌酸钾粉体

采用改进的固相反应合成法,以碳酸钾和草酸铌为原料,少量水为溶剂,充分研磨干燥后得到 KNbO<,3>前驱体,再将前驱体分别于475,600和800℃焙烧3h后得到KNbO<,3>粉体,研究了所制KNbO<,3>粉体的性能.结果表明:该制备方法简单快捷,碳酸钾和草酸铌在研磨过程中发生了离子交换反应.所得KNbO<,3>均...     

大功率CO_2激光器非平衡态合成WO_3/Al_2O_3新型陶瓷催化剂

用大功率 CO2 激光在高温、快速、非平衡态下合成 WO3/ Al2 O3烯烃歧化反应催化剂。利用 XRD、XPS、DTA TG等技术对催化剂的性质进行了研究。表明激光合成催化剂中存在非平衡态的 Alx WO3。低于六价的钨是烯烃歧化反应的活性中心 .同时还考查了催化剂组成、激光功率及熔炼时间与丙烯歧化反应活性之间的关系。     

RTV,LTV硅橡胶对金属长期腐蚀性实验

本文对常用的几种硅橡胶、硅凝胶及其熟化剂、表面处理剂在不同环境,对一些金属及镀层进行了15年长期暴露(存放)试验,以确定对金属的腐蚀程度。其中,单组分硅橡胶的腐蚀性不大;双组分缩合型硅橡胶的催化剂(如二丁基二月桂酸锡等)对铜等金属、镀层有较严重的腐蚀性,熟化剂体系经回流反应处理后,腐蚀性大大降低,不会产生铜绿。加成型的硅凝胶对各种金属及镀层没有腐蚀性。     

α-氰基肉桂酸酯类液晶的合成与性质研究

以对羟基苯甲醛和氰基乙酸乙酯缩合生成α-氰基对羟基肉桂酸乙酯,再与4种酰氯反应生成α-氰基肉桂酸酯类液晶;以对羟基苯甲醛和氰基乙酸丙基苯酚酯缩合生成α-氰基对羟基肉桂酸丙基苯酚酯,再与2种烷基环己基甲酰氯反应生成α-氰基肉桂酸酯类液晶.目标化合物经MS分析确认了结构.通过差示扫描量热仪测量相变温度,对合成产物的液晶相态进行了研究;通过紫外分光光度计测量紫外光谱,研究了合成产物紫外吸收性能.在混合液晶中的应用实验表明,此类化合物可以作为具有液晶性能的紫外吸收剂添加到混合液晶中,改善液晶材料的抗紫外性能.     

其它相关学科与技术

0619478运用PEG相转移催化剂合成β受体阻滞剂Metoprolol酒石酸盐〔刊,中〕/田建文//南昌大学学报(工科版).—2006,28(1).—8-11(G)提供了一种具有应用前景的合成Metoprolol酒石酸盐新工艺。产品以对甲氧乙基苯酚和环氧氯丙烷为原料,在相转移催化剂聚乙二醇400的作用下发生缩合反应合成2-[4-(2-甲氧基乙基)苯氧基]环氧乙烷中间体,中间体再经过胺化反应合成Metoprolol,Meto-prolol与酒石酸成盐生成了Metoprolol酒石酸盐。产物由红外光谱(IR)、核磁光谱(1HNMR)、物理及化学分析等方法证实与目标产物基本一致,总收率达50%。参60619479连…     

超细粒子催化剂作用下碳酸二甲酯的合成

采用浸渍法制备了酸碱双功能催化剂,经过高温焙烧和气流粉碎得到超细粒子催化剂.结果表明,该超细催化剂对于由CO2直接合成碳酸二甲酯的反应具有优良的催化活性,选择性和收率都要优于常规催化剂;结合反应精馏设备,可以将碳酸二甲酯的收率由40%提高至70%.     

红外激光诱导异丙醇催化裂解反应

用CW CO_2激光器研究了异丙醇在有催化剂和无催化剂时的裂解反应。有催化剂存在下,诱导裂解反应所需的阈值激光功率比无催化剂时的小,反应产物取决于异丙醇在催化剂表面上的吸附状态,讨论了激光诱导表面反应的机理。     

ZnO/Cr_2O_3系催化剂的电子显微学结构表征

用透射电子显微术(TEM),微衍射技术(MICRODIFF)、高分辨电子显微术(HREM)对中科院山西煤化所Zno/Cr_2O_3系催化剂进行了初步结构表征,得出了电子衍射谱及相应的高分辨条纹象。井与其X衍射结果及M.D.CONCA.等得出的Zn-Cr混合氧化物催化剂的XRD结果进行了对比,初步认为二者从晶系,点阵常数,及X-衍射谱等都较接近,从而为该催化剂进一步的微观结构研究提供了依据。为揭示其反应性能与结构     

V2O5-TiO2系催化剂载体钠迁移的扫描电镜和能谱分析

V2O5-TiO2体系(简称V-Ti系)负载型催化剂，在某些烃类选择氧化反应中，因其具有较好的选择性，已被广泛采用。但我们在研究工作中遇到一些催化剂经长期反应后活性、选择性有所下降的问题。为探讨其原因，用扫描电镜和能谱仪对催化剂反应前后的形貌和组成进行了分析。     

Investigation of the Electrochemical Stop Etching of Silicon Upon the Fabrication of Cantilevers

Semiconductors - Anisotropic etching in potassium hydroxide (KOH) solution with electrochemical stop is commonly used in the formation of thin silicon membranes of sensitive elements in various...     

The influence of As and Ga prelayers on the metal-organic chemical vapor deposition of GaAs/Ge

GaAs epilayers were grown on Ge by metal-organic chemical vapor deposition (MOCVD) with As or Ga prelayers. The grown epilayers were examined for surface morphology, antiphase domain (APD) presence, and optical quality using optical interference contrast microscopy, molten potassium hydroxide (KOH) etching, and photoluminescence (PL) spectroscopy. The As prelayer results in smooth, shiny, and APD-free epilayers with good optical quality. In contrast, the Ga prelayer results in a rough surface with APDs and higher carbon incorporation.     

氧化沉淀法制备纳米级Mn_3O_4粉体及影响因素

以硝酸锰、氢氧化钠、氨水为原料,采用水解氧化沉淀法制备了nm级Mn3O4粉体材料。通过正交试验优化反应条件得到尺寸分布均匀,团聚程度小,颗粒分散性强的nm级Mn3O4粉体。研究了制备过程中反应温度、pH值、搅拌速度、反应物浓度等因素对产物组成、晶体结构、晶粒尺寸、形貌及颗粒团聚程度的影响。采用激光粒度分析仪(LPSA)、X射线衍射仪(XRD)、扫描电镜(SEM)以及化学滴定实验对反应产物进行了分析表征。实验结果表明,采用水解氧化沉淀法制粉时,可得到纯度较高的Mn3O4,当工艺参数pH值为10、温度40℃、搅拌速度3000r/min,反应物摩尔浓度c(Mn(NO3)2)∶c(NaOH)∶c(NH4OH)=2.4∶4.8∶0.96时,材料二次颗粒团聚程度最弱,分散性最好,一次纳米颗粒尺寸最小。     

Simple Salt‐Coordinated n‐Type Nanocarbon Materials Stable in Air

After more than three decades of molecular and carbon‐based electronics, the creation of air‐ and thermally stable n‐type materials remains a challenge in the development of future p/n junction devices such as solar cells and thermoelectric modules. Here a series of ordinary salts are reported such as sodium chloride (NaCl), sodium hydroxide (NaOH), and potassium hydroxide (KOH) with crown ethers as new doping reagents for converting single‐walled carbon nanotubes to stable n‐type materials. Thermoelectric analyses reveal that these new n‐type single‐walled carbon nanotubes display remarkable air stability even at 100 °C for more than 1 month. Their thermoelectric properties with a dimensionless figure‐of‐merit (ZT) of 0.1 make these new n‐type single‐walled carbon nanotubes a most promising candidate for future n‐type carbon‐based thermoelectric materials.     

聚合物前驱体法制备铌酸钾钠薄膜

以加入和不加入草酸铵两种方法制备氢氧化铌。以碳酸钾、碳酸钠和制得的氢氧化铌为原料,柠檬酸为螯合剂,乙二醇为酯化剂,通过聚合物前驱体法在SiO2/Si基板上制备了铌酸钾钠(KNN)薄膜。研究了草酸铵的添加和不同退火温度对KNN薄膜性质的影响。结果显示:在pH=7.5,金属阳离子与柠檬酸摩尔比为1:3,柠檬酸与乙二醇的摩尔比为2:1时,可以获得均匀稳定的KNN前驱体溶胶。草酸铵的加入优化了薄膜的性能;随着退火温度的增加,薄膜的致密度越来越高。退火温度在850℃时,薄膜结晶性相对较好;900℃退火处理后,薄膜晶粒有定向生长趋势。     

Process optimization and characterization of silicon microneedles fabricated by wet etch technology

In this research, we have optimized a fabrication technique for manufacturing microneedle arrays in standard silicon wafer ((100) orientation) using potassium hydroxide (KOH) wet etching. The etch behaviour of silicon was simulated for different mask shapes and sizes using SIMODE software. In the context of the fabrication process, we demonstrate the influence of the mask design and the processing environment such as etching parameters and etch bath conditions on the formation of silicon microneedle structures (needle height up to 300 μm) and its reproducibility. Single needle shear tests have been carried out to characterize the mechanical stiffness of fabricated microneedles.     

3D Free‐Form Patterning of Silicon by Ion Implantation,Silicon Deposition,and Selective Silicon Etching

A method for additive layer‐by‐layer fabrication of arbitrarily shaped 3D silicon micro‐ and nanostructures is reported. The fabrication is based on alternating steps of chemical vapor deposition of silicon and local implantation of gallium ions by focused ion beam (FIB) writing. In a final step, the defined 3D structures are formed by etching the silicon in potassium hydroxide (KOH), in which the local ion implantation provides the etching selectivity. The method is demonstrated by fabricating 3D structures made of two and three silicon layers, including suspended beams that are 40 nm thick, 500 nm wide, and 4 μm long, and patterned lines that are 33 nm wide.     

Direct metallization of gold patterns on polyimide substrate by microcontact printing and selective surface modification

Patterned gold microstructures were fabricated on a polymer substrate by a novel method involving selective electroless plating and microcontact printing. The micro-sized gold patterns were made by the site-selective chemical modification of polyimide substrate films using aqueous potassium hydroxide solution and microcontact printing with a pitch size in the range of 20-200 μm. The base-treated area of the polyimide film became hydrophilic in the regions where the ion-exchange reactions took place for the subsequent metallization. The hydrophilic patterns were sensitized by placing the film in a solution of PdCl₂ and, subsequently, the activated substrate was immersed in an electroless plating solution of Ni and Au to provide well-developed gold patterns on polyimide substrate films.     

对氟和铝表面反应的研究

X光电子分光镜(XPS)分析被用来界定和比较未接触铝表面、氧接触铝表面和氟接触铝表面的气体扩散器。未接触和氧接触样品铝表面会形成Al2O3,另一边,氟接触表面倾向生成氢氧化氟铝表层。从氢氧化氟铝表层的形成看上去,像是由原有的Al2O3、氟和水蒸气共同反应产生的。扫描电镜(SEM)的显微照相则显示三种样品表面是光学相似的。     

Evaporation induced corrosion of YZ-LiNb03

Evaporation of aluminium film induces corrosion on YZ-LiNb03. Both low and high evaporation rates of Al evaporation are effective. The reaction product, of Al ad-atoms and crystal surface, due to local heating caused by heat of condensation may be the primary reason for the observed corrosion.