硅上取代基对氟化钾催化下取代硅烷酚解反应活性的影响

本文通过色谱定量监测，研究了多种取代硅烷ＲＲ＾１Ｒ＾２ＳｉＨ（Ｒ、Ｒ＾１、Ｒ＾２分别为Ｈ、Ｍｅ、Ｅｔ、Ｂｕ＾１、Ｐｈ和ＥｔＯ）与苯酚，在氟化钾存在下，于相同条件下的反应，定量地表征了Ｓｉ上取代基对其脱氟偶联反应活性的影响。结果表明，Ｓｉ上加有吸电子基团或多个Ｈ原子时有利于反应。     

TiO2含量对BaO-SiO2-B2O3-TiO2系统玻璃性能的影响

分析了３０ＢａＯ（６２－ｘ）ＳｉＯ２－８Ｂ２Ｏ３－ｘＴｉＯ２（ｘ＝０－４０）系统玻璃ＴｉＯ２含量对热膨胀系数α,转变温度Ｔｇ,软化温度Ｔｓ,密度ρ和折射率ｎ的影响,由于Ｔｉ＾４＋配位数的变化,当ＴｉＯ２的摩尔分数约为２０％时,在α,Ｔｇ和Ｔｓ性能曲线上出现极值点,这一现象称之为“钛反常”。研究了３０ＢａＯ－（７０－ｘ－ｙ）ＳｉＯ２－ｘＢ２Ｏ３－ｙＴｉＯ２（ｙ＝０－４０）系统玻璃的密度ρ随ＴｉＯ２和     

胺对镍系催化了二烯聚合规律的影响

以二乙胺为例研究了胺对Ｎｉ（ｎａｐｈ）２－Ａｌ（－Ｂｕ）３－ＢＦ３·ＯＥｔ２＋ｎ—Ｃ８Ｈ１７ＯＨ（简称Ｎｉ－Ａｌ－Ｂ＋ＲＯＨ）和Ｎｉ（ｎａｐｈ）２－Ａｌ（ｉ－Ｂｕ）３－ＢＦ３·ＯＥｔ２＋ＣＨ３ＣＯＯＣ４Ｈ９（简称Ｎｉ—Ａｌ—Ｂ＋ＢＡ）两体系聚合活性和聚合物分子量的影响，并与Ｎｉ—Ａｌ—Ｂ体系进行了对比．考察了通常条件下肢的允许含量，讨论了有胺存在时Ｎｉ／Ｂｄ、Ａｌ／Ｎｉ、Ａｌ／Ｂ摩尔比的变化对聚合规律的影响。结果表明：胺的含量高于２０ｐｐｍ时将使聚合活性和分子量降低，提高催化剂用量可以抑制胺的不利影响。     

SiO2气凝胶的制备与表征

ＳｉＯ２气凝胶是一种低密度的纳米非晶固体材料,以正硅酸乙酯（ＴＥＯＳ）,乙醇（ＥｔＯＨ）和水为原料,以０．０１ｍｏｌ／Ｌ硝酸为催化剂,摩尔比为ＴＥＯＳ：ＥｔＯＨ：Ｈ２Ｏ＝１：５：８,采用溶胶－凝胶法和超临界干燥技术制备了ＳｉＯ２气凝胶,首先,ＴＥＯＳ在室温下水解０．５ｈ制得醇凝胶,然后将乙醇注入醇凝胶以置换其中的水,最后将醇凝胶放入压力容顺并加入适量乙醇,升温至２７０℃,压力可达１０．６ＭＰａ,采     

木素电解加氢伏安曲线及动力学模型的研究

在隔离式电解槽中,以Ｐｔ作阳极,泡沫铅（ＳＰｂ）作阴极,饱和甘汞（ＳＣＥ）作参考电极, ＤＭＦ＋ＥｔＯＨ＋Ｂｕ４ＮＢｒ＋Ｈ２Ｏ作电解加氢体系,测定了木素电解加氢的伏安曲线,用Ｑｕａｓｉ－Ｎｅｗｔｏｎ数值回归法推导了木素电解加氢反应动力学模型。结果表明：在阴极电位Ｖ＝－１．７～－２．８Ｖ之间,木素可进行电解加氢反应。木素电解加氢反应的动力学模型为     

Ni(naph)_2-Al(i-Bu)_3-(BF_3·OEt_2+C_8H_(17)OH+MeCOOBu)体系催化丁二烯聚合

探讨了正辛醇／乙酸丁酯混合溶剂对ＢＦ３·ＯＥｔ２在加氢汽油中的增溶情况，考察了Ｎｉ（ｎａｐｈ）２－Ａｌ（ｉ－Ｂｕ）３－（ＢＦ３·ＯＥｔ２＋正辛醇＋乙酸丁酯）体系催化丁二烯聚合活性和水对该体系聚合活性、聚合物特性粘数、聚合速率、微观结构和相对分子质量的影响。结果表明，该混合溶剂是ＢＦ３·ＯＥｔ２的良好增溶剂。当Ｈ２Ｏ／Ａｌ（摩尔比）≤２．３时，用其增溶的催化体系聚合活性高，可制得门尼粘度高、相对分子质量分布宽、顺－１，４结构含量大于９６％的聚丁二烯。     

镍系新催化剂合成顺丁橡胶的研制

研究了Ｎｉ（ｎａｐｈ）２－Ａｌ（ｉ－Ｂｕ）３－（ＢＦ３．ＯＥｔ２＋ＲＯＨ０体系催化丁二烯聚合的特点，考查了ＲＯＨ／Ｂ摩尔比，Ａｌ／Ｎｉ摩尔比，Ｎｉ／Ｂｄ摩尔比等反应条件对聚合活性及聚合产物分子量的影响。     

Ni（naph）2—Al（i—Bu）3—（BF3.OEt2＋C8H17OH＋MeCOOBu）体系催化丁二…

探讨了正辛醇／乙酸丁酯混合溶剂对ＢＦ３．ＯＥｔ２在加氢汽泡中的增溶情况，考察了Ｎｉ（ｎａｐｈ）２－Ａｌ（ｉ－Ｂｕ）３－（ＢＦ３．ＯＥｔ２＋正辛醇＋乙酸乙酯）体系催化下二烯聚合活性和水对该体系聚合活性，聚合物特性粘数，聚合速率，微观结构和相地分子质量的影响，结果表明，该混合溶剂是ＢＦ３．ＯＥｔ２的良好增溶剂，当Ｈ２Ｏ／Ａｌ（摩尔比）≤２．３时，用其增溶的催化体系聚合活性高，可制得门尼龙粘度高，相对分     

Na2O—Al2O3—B2O3—SiO2系统溶胶,凝胶涂层的振动光谱研究

本文用振动光谱分析了Ｎａ２Ｏ－Ａｌ２Ｏ３－Ｂ２Ｏ３－ＳｉＯ２系统溶胶中的化学反应和用浸渍法制备的凝胶涂层结构。结果表明：部分硼、铝在溶胶陈化初期就与Ｓｉ（ＯＣ２Ｈ５）４的水解或缩聚产物反应形成线性聚合物，宜于浸涂。热处理时涂层中继续形成Ｓｉ－Ｏ－Ｓｉ、Ｓｉ－Ｏ－Ａｌ和Ｓｉ－Ｏ－Ｂ键；基本结构单元为［ＳｉＯ４］、［ＢＯ４］、［ＢＯ３］和［ＡｌＯ４］。     

Ni(naph)_2-Al(i-Bu)_3-BF_3·OEt_2-Et_2O体系催化丁二烯聚合动力学

研究了Ｎｉ（Ｎａｐｈ）２－Ａｌ（ｉＢｕ）３－ＢＦ３·ＯＥｔ２－Ｅｔ２Ｏ体系催化丁二烯的聚合动力学,考察了该体系的动力学曲线、速度方程、聚合度,测定了催化剂利用率、活性中心浓度等动力学参数。聚合速率对单体浓度呈一级关系,表观活化能为４１．０ｋＪ／ｍｏｌ,催化剂利用率约为７．９％。     

A bispecific immunotoxin (DTAT13) targeting human IL-13 receptor (IL-13R) and urokinase-type plasminogen activator receptor (uPAR) in a mouse xenograft model

A bispecific immunotoxin (IT) called DTAT13 was synthesized in order to target simultaneously the urokinase-type plasminogen activator receptor (uPAR)-expressing tumor neovasculature and IL-13 receptor expressing glioblastoma cells with the goal of intratumoral administration for brain tumors. The recombinant hybrid was created using the non-internalizing N-terminal fragment (ATF) of uPA and the IL-13 molecule for binding plus the catalytic and translocation portion of diphtheria toxin (DT) for killing. The 71 kDa protein was highly selective for human glioblastoma in vitro showing no loss on binding compared with DTAT and DTIL13 controls. In vivo, DTAT13 caused the regression of small tumors when administered at 10 micro g/day given on a five-dose schedule every other day. DTAT13 was able to target both overexpressed uPAR and the vasculature, as demonstrated by its ability to kill HUVEC cells. Also, mortality studies indicated that DTAT13 was less toxic than DTAT or DTIL13. These findings indicate that bispecific IT may allow treatment of a broader subset of antigenically diverse patients while simultaneously reducing the exposure to toxin required than if two separate agents were employed.     

锂电子电池材料LiNi1／3Co1／3Mn1／3O2的制备方法

LiNi1／3Co1／3Mn1／3O2作为一种新型的锂离子电池正极材料,其理论容量高达278mAh.g^-1,具有a—NaFeO2型层状结构,制备方法主要高温固相合成法、共沉淀法、流变相反应法、溶胶-凝胶法等,文章对制备方法进行了重点沦述,讨论了相应的电化学性能、结构特征和目前存在的问题,并对层状LiNi1／3Co1／3Mn1／3O2正极材料的发展进行了展望。     

Preparations of lanthanum hexaboride (LaB6) and cerium hexaboride (CeB6)

Due to strong anti-poisoning ability, good emission stability, high emission current density, lanthanum hexaboride (LaB₆) and cerium hexaboride (CeB₆) have been maturely applied in electron emission emitter. In this paper, a new manufacturing method for LaB₆ (or CeB₆) powder was proposed by using La₂O₃ (or CeO₂), B₄C, and Al as raw materials. After high-temperature reaction in the range of 1673–1773 K and the following alkaline leaching at 90°C, LaB₆ or CeB₆ powder with particle size of about 10 μm was obtained. Furthermore, by Al metal flux method, the obtained powder was used to manufacture single crystal block with size of several millimeters.     

锂离子电池正极材料LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2的研究进展

锂离子电池正极材料Li Ni1/3Co1/3Mn1/3O2具有比商业化正极材料——LiCoO2更低廉的成本、更低的毒性、更好的热稳定性,近年来受到广大科研工作者的关注。主要介绍了Li Ni1/3Co1/3Mn1/3O2正极材料的合成改性方法及其近年来在电化学性能方面所取得的成果和进展,并简要概括了该材料结构和发展趋势。不断提高Li Ni1/3Co1/3Mn1/3O2正极材料的振实密度以及电化学性能特别是其在高倍率充放电条件下的循环性能将成为相关科研工作者的研究重点。     

Laser Initiation of Tris(carbohydrazide)metal(II) Perchlorates and Bis(carbohydrazide)diperchlorato‐copper(II)

The literature‐known tris(carbohydrazide)metal(II) perchlorates [M(CHZ)₃](ClO₄)₂ (MMg²⁺ ( 1 ), Mn²⁺ ( 2 ), Co²⁺ ( 3 ), Ni²⁺ ( 4 ), and Zn²⁺ ( 5 )) and the bis(carbohydrazide)diperchloratocopper(II) ( 6 ) were prepared and characterized by elemental analysis, IR and Vis/NIR spectroscopy. The sensitivities toward mechanical, thermal, and electrical stimuli were determined for all complexes 1 – 6 . Following, confined samples of 1 – 6 were irradiated with a monopulsed laser beam at a wavelength of 940 nm. The function times between beginning irradiation and complete decomposition (“breakout” at the end of the device) were measured. Further, the influence of light‐absorbing additives was investigated to proof if the laser initiation mechanism might be photothermal or photochemical. Addition of 1 % active carbon to the samples decreased the function time and the correlated initiation threshold enormously. This was an indication that the initiation mechanism seems to be thermal.     

X-ray photoelectron spectroscopy (XPS) for catalysts characterization

The general principles of X-ray photoelectron spectroscopy (XPS) as applied in the field of heterogeneous catalysis are reviewed. In particular, the use of this technique in the determination of chemical and physical changes of catalysts upon exposure to gaseous molecules and upon different thermal treatments is examined. Furthermore, examples of methods useful in obtaining the dispersion of supported catalysts are described and, for this purpose, theoretical models of the particle-support distribution are also discussed. The XPS characterization of supported Pd–Ag catalysts is reported, emphasising the advantages of using XPS to investigate surface segregation processes. In the case of supported Pd/Pt bimetallic catalysts it is shown how both, Auger and photoelectron peaks, characterized by different kinetic energies, allow to get depth profile non-destructive analysis. Finally the surface behaviour of CoMo catalysts, used for hydrodesulfurization reactions, is investigated on different supports and under different pre-treatment and reaction conditions.     

Effect of the Liquid-Phase Characteristic on the Microstructures and Dielectric Properties of Donor- (Niobium) and Acceptor- (Magnesium) Doped Barium Titanate

Changes in the microstructure and dielectric properties with the variation of the donor/acceptor ratio in BaTiO₃ ceramics were investigated. In donor-rich specimens, a liquid that appeared during sintering did not penetrate into grain boundaries. However, in the acceptor-rich specimens, the grains were separated by a liquid film during sintering. The much higher mobility of the liquid film than that of the grain boundaries was suggested to cause extensive grain growth in acceptor-rich BaTiO₃. The macroscopic homogenization of dopants because of grain growth in acceptor-rich specimens resulted in changes in the dielectric properties.     

PET/PTT共混聚酯的等温结晶行为

使用差示扫描量热仪(DSC)研究不同比例的PET/P1T共混聚酯在205℃的等温结晶行为,并使用Avrami方程对其等温结晶过程进行研究.结晶半周期t1/2,总结晶速率常数k和Avrami指数n的变化表明:在共混体系中,对于PET和PTT而言,另一组分的加入都会对结晶产生阻碍作用,PET与P1T相互影响成核与晶体生长机理.     

A polymer infiltration and pyrolysis (PIP) process model for ceramic matrix composites (CMCs)

This work describes a physics-based model to simulate the polymer infiltration and pyrolysis (PIP) manufacturing process for ceramic matrix composites (CMCs). Models have been developed to characterize volumetric distribution of constituents and track porosity inside the composite at different PIP stages utilizing test data from TGA and DSC characterization of a commercial preceramic polymer. Laboratory experiments were done using C/SiC CMC specimens manufactured with a variable number of PIP cycles in order to obtain inputs for the models, and the analytical results have been shown to agree with porosity determined from physical measurements.     

Chemical ecology ofReticulitermes flavipes (Kollar) andR. virginicus (Banks) (Rhinotermitidae)

Reticulitermes flavipes andR. virginicus have been examined for the presence and possible defense functions of soldiers specific secretions. The cephalic extracts for soldiers of both species contained the identical two major sesquiterpenes which were absent from other castes. The sesquiterpenes have been identified as ₁-cadinene (I) and the corresponding aldehyde (II) by high-resolution nuclear magnetic resonance spectrometry using homonuclear proton decoupling and by high-resolution mass spectrometry. When groups of termite soldiers were exposed to foraging parties of the sympatric native fire ant,Solenopsis geminata, the termites utilized only mechanical defenses. No evidence was obtained to indicate that the ants had been sprayed or coated with either an irritant or toxicant, and there was no evidence that an alarm had been promulgated.