片状h-BCN化合物的高温高压化学合成与表征

以高温烧结三聚氰胺制得的CNH化合物为C、N源,与分析纯单质硼粉以一定比例混合,在5.0~5.5 GPa、1 400~1 500℃高温高压条件下,经化学反应合成了六角硼碳氮(h-BCN)晶体。用傅立叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)对产物进行了表征,结果表明,得到了含碳量较高的六方结构B0.18C0.66N0.16化合物,成分接近于BC4N,硼、碳、氮是以原子化合的形式存在;XRD分析确定该合成产物具有六角网状结构;SEM测量结果表明,B-C-N晶体具有片状六角形貌,尺寸在1μm左右。     

N-硝基苯基脲化合物的合成与表征

一釜合成法合成了五个新的 N-硝基苯基脲类化合物 ,其产率分别为 4 6 .4 %、71.4 %、5 2 .3%、5 5 .4 %和 6 7.7% ,并通过元素分析、红外光谱 ,核磁氢谱对产品进行了结构表征     

系列甲基苯基卟啉-5-氟尿嘧啶化合物的合成与表征

设计合成了6种甲基苯基卟啉-5-氟尿嘧啶化合物。通过红外光谱、紫外-可见光谱、核磁共振谱和质谱对所合成的化合物结构进行了确认。探索出了合成反应的最佳条件和目标化合物的分离纯化方法。实验结果表明,选择DMF为溶剂,反应温度在115℃,反应时间2h,产率较高,A1、A2,B1、B2、C1和C2分别为25.66%、25.02%,24.89%、26.17%、28.43%和24.19%;采用硅胶G(粒径为48—75μm)柱层析,分离效果较好。     

创建原子与分子物理及高温高压物理与高压合成研究基地的回顾与展望

简要介绍了吉林大学原子与分子物理研究所(含高压物理与高压合成)及四川大学原子与分子物理研究所、高温高压物理研究所的创建经过和所取得的主要成就,并略谈今后的发展方向。     

AlNBN复相纳米陶瓷的高温高压合成与表征

利用直流电弧等离子体方法制备了氮化铝纳米粉,用行星式球磨机制备纳米级的氮化硼粉,将这两种纳米粉均匀混合,经过5 GPa、1500 ℃的高温高压处理,最终制备出AlN/BN纳米复相陶瓷,对合成的产物进行了X射线衍射（XRD）、透射电子显微镜(TEM)和扫描电子显微镜(SEM)的分析,得到样品的结构和形貌特征,结果表明合成产物为AlN/BN纳米复相陶瓷.      

高温高压合成顶角氧掺杂型高温超导系列

 简要介绍了(Sr,Ca)_n+1Cu_nO_2n(Cl,O)₂,即三元数法的Cl-“02n”（或四元数Cl-02(n-1)n）超导系列,简称Cl-系超导体。和通常的高温超导体不同,Cl-系的电荷库由卤化物构成,而非通常的氧化物。即Cl-系的导电区和电荷库由顶角氯连接,根据这一结构特点用“顶角氧”掺杂,高压合成了T_c≈80 K的(Sr,Ca)₃Cu₂O₄(Cl,O)₂超导体。该化合物具有和全氧化物高温超导体可比的超导性能,表明高温高压合成全新的卤氧超导新材料的潜力,以及开发卤氧化物高温超导体群的研究前景。     

Sm填充型方钴矿化合物的高温高压合成及电输运特性研究

利用高温高压方法在2 ~ 5.0 GPa和900 K的合成条件下成功合成出系列立方相Sm填充型方钴矿化合物SmxCo4Sb12 ( x= 0.2, 0.6, 0.8 ) 体热电材料,并系统地研究了合成压力及不同的Sm填充分数对其室温下的电输运特性（电阻率、Seebeck系数、功率因子）的影响. 研究结果表明, Sm填充型方钴矿化合物SmxCo4Sb12为n型半导体. 在不同压力下,随着Sm填充分数的增加,Seebeck系数的绝对值和电阻率均呈现降低趋势. 在2 GPa,900 K条件下合成的Sm0.8Co4Sb12化合物功率因子达到最大值5.88 μW /( cm·K2).     

新型BCN化合物的结构表征和相转变

将石墨和六方氮化硼(h-BN)混合粉球磨120h形成的非晶B-C-N粉在4.5GPa，1600K等温退火45min. XRD，TEM和Raman散射测量结果表明，高压合成的产物由晶格常数为a₁=0.2551nm，c₁=0.6716nm的六方Ⅰ相和a₂=1.2360nm，c₂=0.8570nm的六方Ⅱ相组成，其中六方Ⅱ相为B-C-N 新相. 在室温该新相在1279，1368，1398cm^-1出现三个特征Raman峰. 变温Raman测量结果表明，在测量温度T=93K时，样品中的主要相为六方Ⅰ相，随着温度的升高，六方Ⅰ相逐渐向六方Ⅱ相转变，当T>473K时，六方Ⅰ相完全转变成六方Ⅱ相. 当温度从673K降到93K过程中，样品又从六方Ⅱ相逐渐变回到六方Ⅰ相. 对这一相变的机理进行了讨论. 关键词： B-C-N 机械球磨 高温高压 相转变     

水合钴氧化物超导体的合成和表征

最近发现的水合钴氧化物超导体引起了超导领域的强烈兴趣．由于该超导体非常不稳定，因此有关该超导体的合成和表征是个重要的基本课题．本文报道几种典型的合成方法，并对所得到的超导体进行表征．我们将着重介绍利用歧化反应来制备含有很低的钠离子浓度和很高的水合氢离子浓度的钴氧化物超导体的新方法．     

PbTe的高温高压合成

 以高温高压为手段，在4～5GPa压力和700～1 200 K温度条件下，成功地合成出了PbTe。对合成样品进行了X射线测试分析，结果表明，合成的PbTe样品是具有NaCl结构的多晶，而PbTe的取向随着合成压力的升高发生变化。扫描电镜分析结果显示：高压合成的PbTe样品，其晶粒有了明显的取向；电阻率比常压样品低1～2个数量级，并随合成压力的升高而降低；热导率也同时低于常压合成的PbTe样品。以上结果说明，高压合成方法是改善材料性能的重要手段。     

Chemical Synthesis and Characterization of Flaky h-BCN at High Pressure and High Temperature

Hexagonal boron carbonitrogen （h-BCN） compound is synthesized from a mixture of boron powder and CNH compound prepared by pyrolysis of melamine （CaH6N6） under high temperature （1400-1500℃） and high pressure （5.0-5.5 GPa）. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and Raman spec- troscopy are used to determine the chemical composition and bonds of the product. The results show that the product has composition of B0.18C0.64N0.16 （near BC4N） and atomic-level hybrid. X-ray diffraction analysis indicates that the powder has a hexagonal network structure. Scanning and transmission electron microscopy results suggest that h-BCN compound morphology is mainly flaky in width about 1 μm and thickness 200nm.     

Poly(N-methylaniline)/Montmorillonite Composite: Chemical Synthesis,Characterization, and Application in Water Treatment

Poly(N-methylaniline)/montmorillonite (PNMA/MMT) composite particles were obtained by using a simple in situ chemical oxidative polymerization method in hydrochloric acid solutions. Fourier transform infrared (FTIR) spectra, UV-visible absorption spectra and scanning electron microscopy (SEM) were carried out to characterize the as-prepared PNMA/MMT composite. On the basis of spectroscopy and morphology analysis, the probable polymerization mechanism was proposed. The potential application of PNMA/MMT composite for removal of heavy metal ions, such as Cu²⁺ and Zn²⁺, in aqueous solution was also investigated.     

Synthesis and Characterization of Large PbSe Colloidal Quantum Dots

Large colloidal quantum dots of PbSe (first excitonic peak position >2 µm) are synthesized under different conditions of temperature, the concentration of precursors and their ratio, and concentration of oleic acid and diphenylphosphine. The dependence of the optical properties, grain size dispersity, and process yield on the processing conditions is systematically explored and discussed. The Ostwald ripening process and how it affects grain growth is demonstrated. Finally, the results for the dependence of the absorption wavelength on the grain diameter for large nanocrystals are compared to the relationships reported in the literature for smaller nanocrystals.     

Mechanochemical Synthesis and Characterization of GaN Nanocrystals

A solid-state displacement reaction of Ga₂O₃ with Mg₃N₂ has been used to synthesize GaN nanocrystals by mechanochemical processing. X-ray diffraction, transmission electron microscopy (TEM) and selected area electron diffraction (SAED) measurements indicated that the nanocrystals had a hexagonal structure and sizes ranging from 4 to 20nm. Optical absorption and transmission measurement showed the bandgap of the nanocrystals was consistent with that of bulk GaN samples (3.43eV). This study demonstrates that mechanochemical processing has significant potential for the synthesis of GaN nanocrystals in a simple and efficient way.     

8-羟基喹啉锂的合成、表征及发光特性

通过液相反应合成了高纯度、高产率的8-羟基喹啉锂(Liq)粉体,制备了Liq薄膜,通过IR光谱、UV吸收谱、X射线衍射谱、荧光光谱对其结构和性能进行了表征,并利用UV吸收谱、电化学循环伏安法、荧光光谱研究了它的电子能级结构。结果表明,pH值和溶剂对Liq的合成有很大影响,而温度的影响不大。利用真空热蒸镀很容易制备高质量、无定性薄膜,Liq的熔点365℃,具有很高的热稳定性。Liq的LUMO能级2．94eV,HOMO能级5．95eV,光学禁带宽度3．01eV．在363nm紫外光的激发下。产生发光峰在452nm附近、半峰全宽为69．4nm的蓝光发射,发光亮度高,色纯度高。由于电子与声子的强耦合作用以及带隙态的影响,产生了5424cm^-1的斯托克斯频移。     

Synthesis and Optical Characterization of CdS Nanowires by Chemical Process

Cadmium sulfide (CdS) nanostructured materials were synthesized by a wet chemical route without using any capping agent. X-ray diffraction pattern showed the typical interplanar spacings corresponding to the cubic phase of CdS. Transmission electron microscopy studies showed the nanowires formation with length in the range 0.1–1.5 μm and the diameter 25–30 nm. UV–visible optical spectroscopy study was carried out to determine the bandgap of the nanostructured CdS thin films and it showed blue shift with respect to the bulk value. Variation of band gap energies with annealing temperature was also studied in detail. Room temperature photoluminescence of the nano-CdS films was measured and the spectrum showed a broad band centered at ~567 nm, which originated from trap states existing in the forbidden energy gap.     

In Situ Synthesis and Characterization of Polypyrrole/Graphene Conductive Nanocomposites via Electrochemical Polymerization and Chemical Reduction

Polypyrrole/graphene sheets (PPy/GNs) nanocomposite electrodes were in- situ synthesized via electrochemical polymerization and chemical reduction from pyrrole (Py) and graphene oxide (GO). The surface morphologies of the nanocomposites were observed by scanning electron microscopy (SEM). The SEM results showed graphene sheets (GNs) scattered on the surface of the polypyrrole (PPy), and the morphologies of PPy/GNs nanocomposites manufactured by pulse current (PC-PPy/GNs) or direct current (DC-PPy/GNs) were smoother than that of PC-PPy. The electrochemical capacitance properties of the nanocomposite films were measured by cyclic voltammetry (CV), galvanostatic charge and discharge (GC), and electrochemical impedance spectroscopy (EIS) techniques in 3 mol·L^?1 KCl aqueous solutions. The results indicated that the specific capacitance of the DC-PPy/GNs nanocomposite was 13.5% higher than that of a PC-PPy electrode. Comparison of the electrochemical performance of the nanocomposites indicated that the PC-PPy/GNs nanocomposite had higher specific capacitance and better charging/discharging capability than that of the DC-PPy/GNs nanocomposite. The specific capacitance of the PC-PPy/GNs nanocomposite could reach to 280 F·g^?1 at a scanning rate of 100 mV·s^?1.     

高长径比柱状金刚石的高温高压合成与机理研究

为了拓展金刚石的种类和解决金刚石工具使用过程中因把持力不足造成的使用寿命降低等, 在中国式六面顶压机上, 通过对FeNi触媒成分和工艺的优化, 成功合成出高质量长径比大于2.5, 平均粒度在0.8—1.0 mm的柱状金刚石晶体. 该晶体独特的形貌, 将极大改善金刚石工具的在使用过程中出现的"脱粒"现象. 另外, 实验中发现, 柱状金刚石晶体的生长速度也远大于传统晶体的生长速度. 采用扫描电镜(SEM)和能谱(EDS)等手段对柱状金刚石晶体及晶体周围触媒成分进行了表征; 结果表明, 柱状金刚石晶体在生长过程中存在{100}和{111}晶面拉长, 以及包覆在晶体周围的触媒成分偏析. 在此基础上, 阐明了柱状晶体生长机理.     

聚丙烯酰胺衍生物凝胶体系的合成与光谱表征

采用聚丙烯酰胺直接氮烷基化的方法,在PAM的侧链上引入了烯丙基,通过自由基引发交联并水解,合成了聚丙烯酰胺自由基交联的弱凝胶,并研究了其结构、凝胶形成过程以及NaCl浓度对凝胶表观粘度的影响。结果表明：交联比的改变,对交联时间、破胶时间和凝胶强度均有影响,随着交联比的增大,交联时间减少,凝胶强度略有增大;聚丙烯酰胺衍生物交联体系的表观粘度随着NaCl质量浓度的增加而增加,具有良好的抗盐性能。