氨的有效能表

本文根据近年来在能源研究中广为重视的有效能概念和有效能分析法,对化工生产和制冷工程上广泛应用的氨饱和液、饱和蒸汽与过热蒸汽在工程范围内的有效能值进行了计算,给出了在环境温度分别为0℃与25℃下的有效能表。本表不仅使用简便,而且有相当的精度,在节能管理中有实用价值。     

Investigation of the phase transitions of ferroelectric KIO3 and KNbO3 crystals by optical diffraction

Optical diffraction is reviewed as a technique for investigation of the phase transitions in crystals with a multidomain structure. It has been used to study the phase transitions in KIO₃ and KNbO₃ single crystals. Strong optical diffraction bands resulted from electric domains in KNbO₃ crystals and their change with temperature were observed when a laser beam passed through the crystals. The diffraction patterns observed changed abruptly at 427°C, 223°C, and -50°C respectively, at which KNbO₃ crystals undergo structural phase transitions. It is considered that the change of the diffraction patterns with temperature is due to change of the electric domains in the crystals.     

光纤荧光免疫分析系统的研制及应用

将光纤传感技术、荧光分析与免疫分析技术结合,自行设计了Y型分叉光纤、光强可调的光纤固定架及性能优良的荧光测定池,建立了新型光纤荧光免疫系统。系统性能可靠,操作简便,既可进行普通的荧光分析,又可进行光纤荧光免疫分析。将系统用于临床血清标本中肺炎支原体抗体的测试,结果与荧光显微镜法和ELISA法结果一致。该新型光纤荧光免疫系统在临床、环保等领域有广泛的应用前景。     

Preparation of SiO2/TiO2 Janus particles by electrostatic assembly,hydrolysis and calcination

This paper describes a novel chemical method for preparing SiO₂/TiO₂ Janus particles.First,polystyrene（PSt）/SiO₂ particles with a raspberry-like structure are prepared by electrostatic assembly.The influences of the reaction time of sulfonation and the treatment times of polyelectrolyte solutions（PDADMAC,PSS）on PSt and SiO₂ are investigated with respect to the surface charge density of the particles.SiO₂/TiO₂ Janus particles are then obtained by hydrolysis of butyl titanate on the surface of PSt/SiO₂ particles followed by a calcination process.Particle size analyzer,Zeta potential instrument,FTIR,TEM and SEM are used to characterize the particle size,the amount of charge on the surface of PSt and SiO₂ particles and the compositions and morphologies of PSt/SiO₂,SiO₂/TiO₂ and PSt/SiO₂/TiO₂.The diameters of the PSt,SiO₂,PSt/SiO₂ and SiO₂/TiO₂ particles are 2.0 μm,303 nm,2.7 μm and 330nm,respectively.     

一维轴向有机无机异质结肖特基二极管的制备及性能研究

一维有机无机杂化材料的制备一直以来是难点问题, 其不同组分间协同产生的新颖性能及广泛应用前景, 使其成为近年来研究热点. 通过多孔氧化铝模板辅助分步电化学沉积方法, 成功设计和制备了有机导电聚合物聚3,4-乙撑二氧噻吩[poly(3,4-ethylenedioxythiophene), PEDOT]和无机金属银(Ag)的分段式纳米线. 使用扫描电子显微镜(SEM)和透射电子显微镜(TEM)对其形貌和结构进行了表征. 采用顶端接触上电极的方式, 研究了单根PEDOT纳米线和单根PEDOT-Ag异质结纳米线的伏安特性曲线. 结果表明, 单根异质结纳米线展现出肖特基二极管行为, 正向开启电压为0.3 V, 反向击穿电压为1.5 V, 正向开启后电流达到微安数量级.     

Morphotropic phase boundary,segregation effect and crystal growth in the NBT–KBT system

Lead-free piezoelectric materials of sodium–potassium bismuth titanate, (1−x)NaBi(TiO₃)₂–xKBi(TiO₃)₂, ceramics and single crystals were prepared and their crystallographic and dielectric properties were measured. Single crystals with dimensions of several centimeters were grown by using the melt growth technique. The morphotropic phase boundary between rhombohedral and tetragonal symmetry determined by X-ray diffraction and Raman spectra was found at x=0.2. No coexistence of rhombohedral/tetragonal phases was found in the NKBT system. Compositions analyses showed that severe phase segregation occurred during the crystallization of the solid solution. From the segregation point, a homogeneous NKBT crystal near the MPB composition is difficult to grow.     

Fabrication of one-dimensional Fe3O4/P(GMA-DVB) nanochains by magnetic-field-induced precipitation polymerization

One-dimensional (1D) magnetic Fe(3)O(4)/P(GMA-DVB) peapod-like nanochains have been successfully synthesized by magnetic-field-induced precipitation polymerization using Fe(3)O(4) as building blocks and P(GMA-DVB) as linker. The Fe(3)O(4) microspheres without surface modification can be arranged with the direction of the external magnetic field in a line via the dipolar interaction between Fe(3)O(4) microspheres and linked permanently via P(GMA-DVB) coating during precipitation polymerization. The length of peapod-like nanochains can be controlled by magnetic field intensity, and the thickness of polymer shell can be tuned by the amount of monomers. Magnetic measurement revealed that these 1D peapod-like nanochains showed highly magnetic sensitivity. In the presence of magnetic field, 1D magnetic Fe(3)O(4)/P(GMA-DVB) peapod-like nanochains can be oriented and aligned along the direction of external magnetic field.     

Hollow microspheres with covalent‐bonded colloidal and polymeric shell by Pickering emulsion polymerization

Hollow microspheres with SiO₂/polymer binary shell were fabricated from Pickering emulsion stabilized solely by methacryloxypropyltrimethoxysilane‐modified SiO₂ particles, and were characterized by optical microscopy, scanning electron microscopy, Fourier transformation infrared spectrum, thermogravimetric analysis (TGA), and energy dispersive X‐ray spectroscopy. The microspheres were templated by the Pickering droplets and the inner structure was affect by the proportion of crosslinking reagent. TGA result indicated that 60.3% of polymer in the shell was connected with SiO₂ by covalent bond which was formed by copolymerization of styrene and the reactive C?C group on SiO₂ stabilizer. Copyright © 2011 John Wiley & Sons, Ltd.     

Viscosity and IR investigations in the Li2O---B2O3 system

The high viscosity in melts of the Li₂O---B₂O₃ system makes it very difficult to grow large crystals of lithium triborate. The viscosity and IR characteristics of molten li₂O---B₂O₃ system are reported in this paper. When the temperature increases the viscosity of li₂O---B₂O₃ system decreases and follows an Arrhenius-type relationship. With an increasing 13203 ratio in Li₂O---B₂O₃ melts, the viscosity rises gradually to a maximum with a composition Li₂O: 3.513203 then it falls rapidly. In order to find active agents to reduce the viscosity, Na₂O, NaCl, LiF, P205, M003, W03 etc oxides were added to Li₂O---B₂O₃ samples respectively and investigated using the orthogonal method. The experimental results show that the addition of acidic oxides can significantly decrease the viscosity in the Li₂O---B₂O₃ system. For Li₂O: 4.513203, an ideal additive agent is 20wt% Li₂O:: 2MoO₃. Near the composition for crystal growth, the percentage reduction of viscosity is 62.2%. The IR spectra of Li₂O---B₂O₃ system revealed that the BO₄⁻/NO₃⁻ ratio is reduced in the melt using Li₂O: 2MoO₃ as an additive. It is proposed that the M003 reduced the concentration of bridging oxygen atoms of BO₄⁻. The change of structure explains the decline in the viscosity. In the crystal structures of lithium triborate, the matrix spaces are so small that larger other cations than Li+ are very difficult to enter the crystal matrix. So the use of additive agents to reduce the viscosity is a possible method if no new phase appears.