三氧化二铝是导致建筑物火灾的严重隐患

建筑物供电线路中的铜线与铝线连接处常常生成一种灰白物质———三氧化二铝 ,极易引发建筑物火灾。着重介绍和分析这种灰白物质的成分、生成原因、危害以及防止其生成的主要措施。     

对苯二甲酸与丁二醇和乙二醇直接酯化的研究

研究了对苯二甲酸（ＰＴＡ）直接酯化法合成对苯二甲酸丁二醇酯－对苯二甲酸乙二醇酯（ＢＨＢＴ－ＢＨＥＴ）时影响主、副反应的诸项因素以及副反应产物四氢呋喃（ＴＨＦ）的生成规律，提出了抑制ＴＨＦ生成的方法．在合成ＢＨＢＴ－ＢＨＥＴ时，以硫酸钛水解物为催化剂具有较好的效果，催化剂浓度、酯化反应温度及二醇／ＰＴＡ的摩尔比等对主、副反应有较大影响，酯化反应体系的酸性是促进副反应的重要因素，添加适量的碱性物质可有效地控制ＴＨＦ的生成．     

毛细管气相色谱法测定空气中低分了醛酮化合物

利用2，4－二硝基苯肼酸性溶液吸收空气中的醛酮化合物，并用毛细管气相色谱分析生成的腙衍生物。选用SE－30毛细管柱，通过程序升温，可将三维难分离物质对进行有效分离和测定。九种醛酮化合物和最低检出限为0．01－0．13mg/L，可用于测定空气中挥发性醛酮污染物。     

广东汕头韩江三角洲第四系沉积规律及其工程地质特征评价

韩江三角洲第四系是以河流搬运为主而形成的三角洲相沉积物。部分地带缺失底积层沉积物;前积层中具有３个大旋回沉积韵律,每个旋回从下往上颗粒由细变粗,具典型的“海退序列”。三角洲的形成晚期为海边洼地或沼泽地,形成一套厚为２０～２５ｍ的以淤泥为主的软粘土层。因此,区内表层或浅部不存在良好的建筑物基础持力层。较好的建筑物基础持力层均分布于前积层３个旋回顶部的砂层,埋深顶面分别为－２０～－２５ｍ、－３０～－３５ｍ、－４０～－４５ｍ;在近海边一带,花岗岩埋深较浅,为－４５～－５５ｍ,是建筑物基础的良好持力层。     

对苯二甲酸与丁二醇和乙醇直接酯化的研究

研究了对苯二甲酸（ＰＴＡ）直接酯化法合成对苯二甲酸乙二醇酯－对苯二甲酸乙二醇酯（ＢＨＢＴ－ＢＨＥＴ）时影响主、副反应的诸项因素以及副的反应产物四氢呋喃（ＦＨＦ）的生成规律，提出了抑制ＴＨＦ生成的方法，在合成ＢＨＢＴ－ＢＨＥＴ时，以硫酸钛水解物为催催化剂具有较好的效果，催化剂浓度、酯化反应温度及二醇／ＰＴＡ的摩尔比等对主、副反应有较大影响，酯化反应体系的酸性是促进副反应的重要因素，添加适量的碱性物质     

啤酒花中单宁的测定

根据福林－丹尼斯试剂与单宁生成深兰色物质，提出了吸光光度法测定啤酒花中单宁的方法。结果表明：兰色物质的最大吸收波长为７６０ｎｍ；摩尔吸光系数为３０７２×１０４Ｌｍｏｌ·ｃｍ；线性范围为０～４２ｍｇ／Ｌ；回收率在１０８８％～９５０％之间；变异系数为１６４％。     

论α—亚麻酸的必需性

本文从生物膜和二十碳酸衍生物两方面论述了α－亚麻酸的必需性，缺乏Ｎ－３多烯酸，如α－亚麻酸及二十二碳六烯酸（ＤＨＡ），降低视网膜和大脑的ＤＨＡ水平，视觉敏锐度降低了，智力下降；α－亚麻酸的摄入提高组织２０：５Ｎ－３浓度，调节二十碳酸衍生物活性物质的生成，抗凝血，扩张血管，抗炎症等功用，对正常的生理活动起着重要的作用，是人体和动物的必需脂肪酸，α－亚麻酸的需求量为０．５％～１．２％（能量）。     

天然沸石在油气井固井中的应用之二—沸石油井水泥水化反…

分析了天然沸石做为油井水泥外掺料的晶体结构方面的依据，回顾沸石水泥水化的机理、根据Ｘ－射线衍射，扫描电镜，能谱分析的结果说明了沸石油井水泥的水化作用特征，证明了沸石与油井水泥发生化学反应并生成了凝胶状物质，指明了不同沸石含量的沸石油井水泥微观结构。     

一种建筑物多分辨网格的生成及显示算法

基于顶点对迭代收缩的表面简化方法,提出一种建筑物多分辨网格的生成与显示算法.考虑建筑物自身特点,该算法改进了边界保持方法,提高了自动生成的多分辨率建筑物网格的质量,为提高实时浏览速度.该算法简化了顶点对收缩中矩阵求逆的方法,通过建立可逆简化链表记录每次视点变化时的收缩信息,有效提高了视距拉伸浏览的实时性.实验结果显示该算法有效.     

高香草酸-H_2O_2-HRP荧光酶联免疫分析测定HRP的研究

提出了高香草酸－H2O2－HRP荧光酶联免疫分析测定HRP的新方法。该法基于HRP催化H2O2氧化高香草酸生成能产生荧光的物质，该物质在Ex＝317nm激发光作用下产生荧光，通过测定在Em＝421nm处的荧光强度，间接测定HRP的含量。在所选定的实验条件下，对HRP测定线性范围为1．0×10（-10）～1．0×10（-8）g／mL，检测限为1．0×10（-10）g／mL。     

Ba3La2Ti2Ta2O15: A new microwave dielectric of A5B4O15-type cation-deficient perovskites

The synthesis, structure and properties of a new A5B4O15-type cation-deficient perovskite Ba3La2Ti2Ta2O15 were discribed. The compound was prepared by the conventional solid-state reaction route. The phase and structure of the ceramics were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）. The results reveal that the compound is successfully synthesized. The compound crystallizes in the trigonal system with unit cell parameter a=5.6730（2） A, c=11.6511（2） A, V=324.93（1） A^3 and Z=1. The microwave dielectric properties of the ceramic are studied using a network analyzer, and it shows a high dielectric constant of 45.1, a high quality factors with Q×fof21 029 GHz, and a positive τf of 5.3 ppm℃^-1.     

低介Ba(Al0.98Co0.02)2Si2O8-Ba5Si8O21基LTCC微波介质陶瓷的研究

采用传统固相反应法,按摩尔比合成0.7Ba(Al_0.98Co_0.02)₂Si₂O₈?0.3Ba₅Si₈O₂₁(BACS-BS)基陶瓷,分析Li₂O-B₂O₃(1wt%)(L-B)烧结助剂对其烧结特性、相组成和微波介电性能的影响,探讨0.7BACS-0.3BS+1wt%(L-B)陶瓷理论与实验介电常数(ε_r)的差异。结果表明:添加1wt%(L-B)烧结助剂能有效降低0.7BACS-0.3BS基陶瓷的烧结温度(950 ℃),但严重影响其微波介电性能;在950℃烧结的0.7Ba(Al_0.98Co_0.02)₂Si₂O₈-0.3Ba₅Si₈O₂₁+1wt%(Li₂O-B₂O₃)陶瓷具有较好的微波介电性能,其ε_r=7.56, Q×f=13 976 GHz, τ_f=?6.32 ppm/℃;0.7BACS-0.3BS+1wt%(L-B)复合陶瓷与Ag电极有很好的化学相容性,这为其在LTCC技术的应用奠定了良好的基础。     

Electrical conductivity of （Na3AlF6-40%K3AlF6）-AlF3-Al2O3 melts

The effects of contents of AlF3 and Al2O3, and temperature on electrical conductivity of （Na3AlF6-40%K3AlF6）- AlF3-Al2O3 were studied by continuously varying cell censtant （CVCC） technique. The results show that the conductivities of melts increase with the increase of temperature, but by different extents. Every increasing 10 ℃ results in an increase of 1.85 × 10^-2, 1.86× 10^-2, 1.89 × 10^-2 and 2.20 × 10^-2 S/cm in conductivity for the （Na3AlF6-40%K3AlF6）-AlF3 melts containing 0%, 20%, 24%, and 30% AlF3, respectively. An increase of every 10 ℃ in temperature results an increase about 1.89× 10^-2, 1.94 × 10^-2, 1.95 × 10^-2, 1.99× 10^-2 and 2.10× 10^-2 S/cm for （Na3AlF6-40%K3AlF6）-AlF3-Al2O3 melts containing 0%, 1%, 2%, 3% and 4% Al2O3, respectively. The activation energy of conductance was calculated based on Arrhenius equation. Every increasing 1% of AlF3 results in a decrease of 0.019 and 0.020 S/cm in conductivity for （Na3AlF6-40%K3AlF6）-AlF3 melts at 900 and 1 000 ℃, respectively. Every increase of 1% Al2O3 results in a decrease of 0.07 S/cm in conductivity for （Na3AlF6-40%K3AlF6）-AlF3-Al2O3 melts. The activation energy of conductance increases with the increase in content of AlF3 and Al2O3.     

一种基于 MXene 的Fe2O3/Nb2O5/Nb4C3Tx 高灵敏丙酮传感器

MXene 具有较大比表面积和优异的导电性, 当与金属氧化物半导体结合时可以抑制片层团聚, 还可以大大提高载流子转移速率, 提高气敏性能。通过简单的水热和煅烧两步法成功合成了Fe₂O₃/Nb₂O₅/Nb₄C₃T_x 三元复合材料。通过表征, Fe₂O₃ 微米球分布在 MXene 纳米片层之间。气敏测试结果表明, 与原始Fe₂O₃相 比, Fe₂O₃/Nb₂O₅/Nb₄C₃T_x 传感器对丙酮的响应能力有明显的提高。传感器灵敏度高, 选择性较好, 对环境中 浓度为 5 ×10^?6 的丙酮响应高 (R_a /R_g = 7.81, 30% RH), 响应和恢复速度快, 具有出色的重复性和长期稳定性。Fe₂O₃/Nb₂O₅/Nb₄C₃T_x 传感器具有良好的气敏性能, 主要因为三元复合材料提供了较大比表面积和丰富的氧空位, 增强了活性位点, 使得气体易于在传感器表面扩散, 为开发丙酮敏感复合材料提供了参考。     

Preparation and electrical-magnetic properties of Co0.6Cu0.16Ni0.24Fe2O4/MWCNTs composites

Co0.6Cu0.16Ni0.24Fe2O4/multi-walled carbon nanotube nanocomposites (CCNF/MWCNTs) were synthesized by solution filling method.The phase structure,thermal stability,morphology and electrical-magnetic properties of the samples were characterized by means of modern testing technology.The effect of iron concentration,filling time,sintering temperature on their electrical and magnetic performance was discussed.The results indicated that conductivity was related to the content of MWCNTs,while the magnetism correlated with the volume fraction of the filled CCNF in the composites.When the optimal condition satisfied the filling time of 18 h,ferric concentration of 0.25 mol L-1 and sintering temperature of 350°C,the prepared composite had the best magnetic loss performance,and its minimum reflection loss reached-22.47 dB on 9.76 GHz,the available bandwidth was beyond 2.0 GHz.Hence,the obtained composite can be used as advancing absorption and shielding material due to its favorable microwave absorbing property.     

Ca0.9Ce0.1Ti0.8Al0.2SiO5在水热作用下的化学稳定性

通过固相法合成掺铈榍石固溶体(Ca0.9 Ce0.1Ti0.8Al0.2SiO5),采用PCT粉末浸泡试验法,借助X射线衍射(XRD)、扫描电镜(SEM)、电感耦合等离子体发射光谱(ICP-OES)等分析测试手段,研究掺铈榍石固溶体在热液作用下的稳定性.实验结果表明,掺铈榍石固化体在不同条件下(温度150～ 200℃,0.476～1.554 MPa,pH值5～9),都具有良好的稳定性.随着浸泡时间的增加,各元素的归一化浸出率逐渐降低并保持在较低水平.     

Synthesis and characterization of Mg3(PO4)2-coated Li1.05Ni1/3Mn1/3Co1/3O2 cathode material for Li-ion battery

Mg₃(PO₄)₂-coated Li_1.05Ni_1/3Mn_1/3Co_1/3O₂ cathode materials were synthesized via co-precipitation method. The morphology, structure, electrochemical performance and thermal stability were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS), charge/discharge cycling and differential scanning calorimeter (DSC). SEM analysis shows that Mg₃(PO₄)₂-coating changes the morphologies of their particles and increases the grains size. XRD and CV results show that Mg₃(PO₄)₂-coating powder is homogeneous and has better layered structure than the bare one. Mg₃(PO₄)₂-coating improved high rate discharge capacity and cycle-life performance. The reason why the cycling performance of Mg₃(PO₄)₂-coated sample at 55 °C was better than that of room temperature was the increasing of lithium-ion diffusion rate and charge transfer rate with temperature rising. Mg₃(PO₄)₂-coating improved the cathode thermal stability, and the result was consistent with thermal abuse tests using Li-ion cells: the Mg₃(PO₄)₂ coated Li_1.05Ni_1/3Mn_1/3Co_1/3O₂ cathode did not exhibit thermal runaway with smoke and explosion, in contrast to the cells containing the bare Li_1.05Ni_1/3Mn_1/3Co_1/3O₂. Funded by the National Natural Science Foundation of China (No. 20273047)     

Modification of LiCo1/3Ni1/3Mn1/3O2 cathode material by CeO2-coating

LiCo_1/3Ni_1/3Mn_1/3O₂ was coated by a layer of 1.0 wt% CeO₂ via sol-gel method. The bared and coated LiMn_1/3Co_1/3Ni_1/3O₂ was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammogram (CV) and galvanotactic charge-discharge test. The results show that the coating layer has no effect on the crystal structure, only coating on the surface; the 1.0 wt% CeO₂-coated LiCo_1/3Ni_1/3Mn_1/3O₂ exhibits better discharge capacity and cycling performance than the bared LiCo_1/3Ni_1/3Mn_1/3O₂. The discharge capacity of 1.0 wt% CeO₂-coated cathode is 182.5 mAh·g⁻¹ at a current density of 20 mA·g⁻¹, in contrast to 165.8 mAh·g⁻¹of the bared sample. The discharge capacity retention of 1.0 wt% CeO₂-coated sample after 12 cycles reaches 93.2%, in comparison with 86.6% of the bared sample. CV results show that the CeO₂ coating could suppress phase transitions and prevent the surface of cathode material from direct contact with the electrolyte, thus enhance the electrochemical performance of the coated material.     

Electrolysis expansion performance of semigraphitic cathode in [K3AlF6/Na3AlF6]-AlF3-Al2O3 bath system

The electrolysis expansion of semigraphitic cathode in [K₃AlF₆/Na₃AlF₆]-AlF₃-Al₂O₃ bath system was tested by self-made modified Rapoport apparatus. A mathematical model was introduced to discuss the effects of α _CR (cryolite ratio) and β _KR (elpasolite content divided by the total amount of elpasolite and sodium cryolite) on performance of cathode electrolysis expansion. The results show that K and Na (potassium and sodium) penetrate into the cathode together and have an obvious influence on the performance of cathode electrolysis expansion. The electrolysis expansion and K/Na penetration rate increase with the increase of α _CR. When α _CR=1.9 and β _KR=0.5, the electrolysis expansion is the highest, which is 3.95%; and when α _CR=1.4 and β _KR=0.1, the electrolysis expansion is the lowest, which is 1.28%. But the effect of β _KR is correlative with α _CR. When α _CR=1.6 and 1.9, with the increase of β _KR, the electrolysis expansion and K/Na penetration rate increase. However, when α _CR=1.4, the electrolysis expansion and K/Na penetration rate firstly increase and then decrease with the increase of β _KR. Foundation item: Project (2005CB623703) supported by the Major State Basic Research and Development Program of China; Project (2008AA030502) supported by the National High-Tech Research and Development Program of China     

Characteristics of LiCoO2, LiMn2O4 and LiNi0.45Co0.1Mn0.45O2 as cathodes of lithium ion batteries

LiNi_0.45Co_0.10Mn_0.45O₂ was synthesized from Li₂CO₃ and a triple oxide of nickel, cobalt and manganese at 950 °C in air. The structures and characteristics of LiNi_0.45Co_0.10Mn_0.45O₂, LiCoO₂ and LiMn₂O₄ were investigated by XRD, SEM and electrochemical measurements. The results show that LiNi_0.45Co_0.10Mn_0.45O₂ has a layered structure with hexagonal lattice. The commercial LiCoO₂ has sphere-like appearance and smooth surfaces, while the LiMn₂O₄ and LiNi_0.45Co_0.10Mn_0.45O₂ consist of cornered and uneven particles. LiNi_0.45Co_0.10Mn_0.45O₂ has a large discharge capacity of 140.9 mA · h/g in practical lithium ion battery, which is 33.4% and 2.8% above that of LiMn₂O₄ and LiCoO₂, respectively. LiCoO₂ and LiMn₂O₄ have higher discharge voltage and better rate-capability than LiNi_0.45Co_0.10Mn_0.45O₂. All the three cathodes have excellent cycling performance with capacity retention of above 89.3% at the 250th cycle. Batteries with LiMn₂O₄ or LiNi_0.45Co_0.10Mn_0.45O₂ cathodes show better safety performance under abusive conditions than those with LiCoO₂ cathodes. Foundation item: Project(50302016) supported by the National Natural Science Foundation of China; Project(2005037698) supported by the Postdoctoral Science Foundation of China