添加剂在碱性锌锰电池锌粉中的应用

介绍了各种无汞碱性锌锰电池锌粉用无机添加剂(如:铟、铋、钙及镁、铝、稀土金属等),以及含不同添加剂的锌粉的特性;指出各类添加剂能满足各型号碱性锌锰电池的需要。     

Evaluation of microscopic structural randomness in SiO2 by analysis of photoluminescence decay profiles

Microscopic structural randomness in SiO₂, a typical electrical insulating material, was evaluated by observing the decay profile of the photoluminescence due to oxygen vacancies (≡Si-Si≡). As samples with different degrees of randomness, an ion-implanted thermal SiO₂ film, SiO₂ films formed by plasma-enhanced chemical vapor deposition of tetraethoxysilane with and without doped fluorine, a buried oxide film prepared by SIMOX (separation by ion-implanted oxygen), and a bulk silica glass prepared by the soot-remelting method were tested. By analyzing the decay profile with a stretched exponential function, it was found that the deviation of the decay profile from a single exponential function is larger in the samples whose infrared absorption properties and HF etch rate suggest greater structural randomness. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 119 (3): 1–6, 1997     

碱性锌锰电池用锌粉的现状及发展

碱性锌锰电池用锌粉在中国已经过20多年的发展。从环保要求、生产成本、电池性能要求等方面分析了碱性锌锰电池用锌粉的现状;指出电池锌粉的发展将出现变化,并提出应对措施。     

国内碱锰电池用无汞锌粉的发展动态

从有害杂质、合金成分等化学组份,形貌、粒度分布、松装密度等物理性能方面,阐述了国产碱性锌锰电池用无汞锌粉近几年的技术进步;分析了国内无汞锌粉的市场现状和发展趋势;探讨了我国无汞锌粉工业存在的主要问题,我国无汞锌粉工业的崛起推动了碱锰电池产业的发展,同时,一定程度的盲目发展也面临着新的市场挑战;今后低铟锌粉将在市场中占主导地位。     

Characteristics of silver powders synthesized from silver 2-ethylhexanoate and Di-n-octylamine

Uniform spherical submicron silver powders were synthesized from a long-chain alkyl carboxylate of silver 2-ethylhexanoate and an alkylamine of di-n-octylamine in this study. The decomposition of silver 2-ethylhexanoate was observed to accelerate significantly in the presence of di-n-octylamine. SEM results revealed that submicron silver powders with sizes ranging from 200 nm to 300 nm and a high tap density of 4.0 g/cm³ were successfully prepared at 150 °C for 3 h in air. TGA reveals that approximately 1.2 wt.% organic residues composed mainly of 2-ethylhexanoate with a slight amount of di-n-octylamine were attached to the silver particles, as confirmed by the FTIR and XPS results. To evaluate the feasibility for practical applications, silver paste prepared from the silver powders synthesized in this study (NAG 80 paste) was examined and characterized, and the results were compared with those of two commercially available powders (SF80 and GH67 pastes). The electrical resistivities of the NAG80 films fired at 300 and 500 °C respectively read 1.8?×?10^?5?Ω-cm and 1.1?×?10^?5?Ω-cm, both superior to those of the SF80 and GH67 films. The fine quality of the uniform submicron spherical silver powders was verified and its potential use in thick film conductors confirmed.     

电池用锌粉分析方法

无汞碱性锌锰电池用锌粉中有害杂质的含量板微，锌粉中加入了铝、铋、钙、铟、铅等金属缓蚀剂后，合金成分对某些原有的分析方法有干扰，杂质含量降低后，有的老方法灵敏度达不到，促进了新分析方法的研究和建立。对无汞碱性锌锰电池用锌粉的分析方法进行评述，以便读更好地选择。     

碱性锌-锰电池用锌粉中砷和锑的测定

研究了氢化物发生-原子荧光光谱法(HGAFS)测定电池用锌粉中微量砷和锑的最佳条件,对仪器的条件、酸度的影响、预还原剂的用量、还原剂的用量、共存元素的干扰进行了优化设计,结果令人满意,方法的检出限As:0.064μg·L-1,Sb:0.092μg·L-1;精密度As:1.2%,Sb:1.3%;回收率As:92.6%～106.7%,Sb:89.8%～97.7%。     

Device applications of transparent oxide semiconductors: Excitonic blue LED and transparent flexible TFT

Recent progress in oxide-based transparent optoelectronic devices is reviewed. It is important to understand electronic structures inherent to oxides in order to develop new materials and to find suitable device applications that oxide materials can have distinct advantages over conventional semiconductors. Two new transparent oxide semiconductors, (i) p-type layered oxychalcogenides LaCuOCh (Ch = chalcogen), and (ii) large-mobility amorphous oxide semiconductors (AOSs), are taken as examples. Their peculiar properties are discussed in comparison with conventional semiconductors based on consideration of electronic structures. Two associated devices, an excitonic light-emitting diode using LaCuOCh and transparent flexible thin film transistors using AOSs, are also shown.     

甘氨酸-硝酸盐法制备Sm掺杂CeO2电解质及性能研究

甘氨酸-硝酸盐燃烧法合成Sm掺杂CeO2(SDC)电解质材料,通过XRD和扫描电子显微镜对不同甘氨酸与金属阳离子比例(G/N)制备粉末的结构和形貌进行了研究。比表面积测量结果显示,不同G/N比影响合成粉末的比表面积,导致粉末的烧结性能不同。G/N比为2合成的粉末在1300℃烧结2h可以达到97%的理论密度。合成不同含量Sm掺杂铈基氧化物SmxCe1-xOδ(x=0.125,0.15,0.175,0.20,0.225,)电解质材料,制备电解质支撑的单电池,电解质厚度为1mm,采用泥浆喷涂工艺在电解质上制备60%(质量百分数)NiO-SDC阳极层,在1300℃共烧结2h,Ag浆作为阴极组成单电池,以H2和空气为燃料和氧化气体电池性能测试显示,Sm0.175Ce0.825Od为电解质的单电池性能最好,800℃最大功率密度达283mW/cm2。     

Effect of Sn/Zn ratio on structure and photoluminescence properties of SnO2@ZnO composites

ABSTRACT

The SnO₂@ZnO composites, with Sn/Zn molar ratio (Sn/Zn–ratio) from 4:1 to 8:1, were successfully prepared via two–step hydrothermal method. The microstructure and morphology of the as–prepared Sn/Zn–ratio–dependence SnO₂@ZnO composites were investigated. Furthermore, a reasonable growth mechanism of SnO₂@ZnO composites was proposed and the results indicated that the dispersity of SnO₂ nanowires on the ZnO nanorods surface was obviously influenced by the Sn/Zn–ratio. The photoluminescence (PL) properties of the Sn/Zn–ratio–dependence SnO₂@ZnO composites were investigated. The results showed the opposite intensity change of ultraviolet (UV) and visible emission while the Sn/Zn–ratio increased. In addition, the possible emission mechanisms were also discussed that the UV emission is attributed to free–exciton recombination at the near–band edge and the potential difference between SnO₂ and ZnO result in the visible emission.     

代汞缓蚀剂用In2O3纳米粉体的研究

描述了高纯氧化铟（In2O3）纳米粉末的制备方法及自制的In2O3纳米粉末的物理、化学性能。从BET测试结果和TEM照片看出,该粉末为比表面积大、分散性好的纳米粉末。与进口In2O3粉末进行应用对比表明：新电的电性能以及高温（60℃）贮存后的析气量均差别不大。测试结果显示：该纳米粉末具有良好的缓蚀效果。     

镍粉对Ni(OH)2电极电化学行为的影响

利用恒电流充放电、循环伏安法研究了过量镍粉对Ni（OH）2电极电化学行为的影响,并用X射线衍射分析了放电后镍粉结构的变化。结果表明：电极中的镍粉在碱性电解液中会氧化成活性物质β—Ni（OH）2,从而对放电容量作出贡献,同时因氧化使导电性降低而影响Ni（OH）2的放电效率。利用镍粉作空白试验对照,将电极在第4～6周期的放电容量扣除镍粉的贡献可尽量准确地测定Ni（OH）2的放电容量。     

锌粉及锌合金中铝的测定

采用铬天青S分光光度法测定锌粉及锌合金中的铝.用六次甲基四胺作缓冲液,酸度控制在pH4.9～5.5之间,EDTA-Zn作掩蔽剂,氟化铵络合铝作褪色空白,掩蔽铟、铋、铅、铁、铜、镍、汞的干扰,采用基体匹配法和褪色空白加以消除基体锌、镉、钙、镁干扰.此方法不需分离锌粉及锌合金中的干扰元素,分析手续简单经济,稳定性好,掩蔽能力强,易操作,精密度高.     

Triboelectric charging of polymer powders in fluidization andtransport processes

In this paper, we investigated the role of tribocharging in fluidization, flowability, and q/m distribution as functions of particle size distribution (PSD), fluidization time, and transport tubes of different materials. A charge separator was used to determine mass fractions of powder that had positive, zero, and negative charges. For the two acrylic powders tested, one (Sample A) had volume median diameter d₅₀ 18.73 μm while the other (Sample B) had d₅₀ 24.17-μm diameter. During fluidization for 1 h at a relative humidity of 57%, powder B acquired positive charge with charge-to-mass ratio Q/M=0.3 μC/g, and 25% of the powder mass had negative charge with Q/M=-0.36 μC/g. About 35% of the powder mass had particles with nearly zero net charge. Tribocharging during fluidization and transport processes was attributed to particle-particle and particle-wall collisions. Of the total charged particles, about 60% were positively charged while 40% were negatively charged. Each particle may have had patches of charges on its surface, some positive and some negative. The sum total of all patches of charges may yield positive, negative, or essentially neutral polarities on a given particle. For a relatively narrow size distribution of powder, the PSD is often assumed to be conserved during fluidization. A shift in PSD toward larger diameter particles was anticipated because of the possible elutriation of the fine fraction of the powder, but the actual shift was only about 1 μm after 1 h of fluidization. Under identical operational conditions using a fluidized bed, powder pump, transport hose, and corona gun, powder B had nearly twice the mass flow rate of Powder A. Such differences in flowability of powders influence charging and deposition efficiencies in powder coating applications     

Bipolar charging of poly-disperse polymer powders in fluidized beds

It is well known that many common industrial powder handling operations such as pneumatic transport, mixing, and fluidization may produce a net charge on the powder particles. However, it is less well known that the net charge is often the result of a bipolar charge distribution in which the smaller particles acquire charges of a polarity opposite to those on the larger. This suggests contact charging between particles having the same chemical makeup. Very little quantitative data exist in the literature concerning this observation and no acceptable explanation currently exists. The purpose of this paper is to review the previous published work and to describe some results showing bipolar charging using polymer powders in fluidized beds. A new measurement system is described for measuring the bipolar charge distribution. This consists of a vertical array of seven Faraday pail sensors, which can selectively detect different charge components based upon particle size (gravity segregation) and charge (space-charge repulsion). For the experiments reported here the charge and mass values were measured for each sensor allowing the calculation of charge-to-mass ratio (Q/M). In addition, size distribution and surface analyses were carried out for representative samples of the powder components. Data are presented for several types of polymer powders (surface area mean diameter <100 /spl mu/m). The results show that, for a given powder, even though the net charge may be positive or negative, the smaller particles show a negative charge and the coarser particles positive. These results are compared under several possible hypotheses. Each of these possibilities is examined using the measurements of the Q/M for different size fractions and the results of surface analysis and particle size distributions of these fractions.     

Induced magnetoelectric coupling and photoluminescence response in solution-processed CoFe2O4/Pb0.6Sr0.4TiO3 multiferroic composite film

ABSTRACT

The combined effects of interface (represented by the extrapolation length) and thickness on polarization of ferroelectric thin films derived by sol-gel method are investigated using Gingzburg-Landau-Devonshire theory. The polarization profile, the average and the maximal polarization are numerically modeled and analyzed for various film thicknesses and degrees of interface imperfection. Results show that the polarization near the interface is dramatically suppressed due to the interface effects, and the average and maximal polarizations both decrease significantly with the reduced thickness down to 50 nm or below. The simulation results indicate that the interface effects play a major role behind the polarization reduction when the thickness is decreased.     

Blueshift of absorption edge and photoluminescence in Al doped ZnO thin films

ABSTRACT

Pure and Al doped ZnO thin films are fabricated on quartz substrates by sol–gel method, and then analyzed by X-ray diffraction (XRD), transmittance spectra, and photoluminescence (PL) measurements respectively. XRD results reveal that all the thin films have a preferential c-axis orientation. With the increase of Al doping, however, the peak position of the (002) plane is shifted to a low 2θ value. On the other hand, the data of spectrometer transmittance are obtained, with which the band gap energies of Al doped ZnO films are calculated by a linear fitting method. The band gap is found to be broadening, and the absorption edge has an obvious blueshift to the shorter wavelength with increasing dopant concentration. PL measurement is also conducted, and deep-level (DL) emission and near band edge (NBE) emission are observed in pure ZnO thin films. But DL emissions are depressed when Al is doped into thin films. And the peak of NBE emission has a blueshift to the region of higher photon energy as the Al concentration increases, a performance which tallies with observations through the optical transmittance data. The study demonstrates that the blueshift of optical properties in the ZnO:Al films, can nevertheless be easily manipulated and managed by controlling dopant concentration, a big plus to the said films in their applications in broadband UV photodetectors with highly tunable wavelength resolution.     

High-speed photoluminescence mapping of III-V epitaxial layers forlight-emitting diodes

Three examples are presented which demonstrate how photoluminescence wafer mapping is routinely used in the development and manufacturing of III-V optoelectronic materials and devices. Statistical data from the full-wafer PL scans of epitaxial layers is correlated with the device performance of fabricated light-emitting diodes, and can be used to predict the brightness, uniformity and yield of these devices     

无汞锌粉生产过程的质量控制

讨论了无汞锌粉生产过程(含合金化、雾化、筛分等)中影响产品质量的因素及相应的控制手段;指出,通过加强对合金化、雾化和筛分过程的有限控制,减少各流程的污染,能生产出高质量的无汞锌粉。同时指出,析气量检测是测试锌粉质量好坏的一种重要手段,但析气量检测结果仅能作为锌粉生产厂家的参考依据。     

HDDR Nd2Fe14B磁粉微结构和磁性能研究

采用未经均匀化热处理的SC(Strip casting)合金铸片为原料制备HDDR磁粉,着重研究了HDDR工艺的歧化阶段和缓慢脱氢阶段的氢气压强对Nd2Fe4B磁粉微结构和磁性能的影响.研究表明:合适的歧化压强(Pd)和缓慢脱氢压强(Psd)不仅有利于磁粉各向异性的获得,同时也有利于磁粉微结构的优化和磁性能的改善.磁粉...