低压AB类电流模电路设计

描述实现低电源电压的电流模电路的设计方法.本方法是建立偏置电路的基础上,利用多晶硅电阻和附助差分放大器,将对电源电压需求降到VT 3VDS.sat.用电流镜和跨导器的设计举例说明这种设计方法的运用.采用0.5-um工艺,PSPICE仿真结果证实上述电路在低压能力和速度上能达到期望的性能.     

双面国家A级高强度AB楞纸板边压和耐破强度试验研究

依据国家测试标准,结合产品温湿度的实际流通环境及实验设备环境,制定了双面国家A级高强度AB楞纸板边压和耐破强度试验方案。试验表明,温度变化对边压强度影响不大,在40%~90%RH范围内最大相对误差不超过13.35%。温度变化对耐破强度影响也不大,在40%~90%RH范围内最大相对误差不超过7.37%。因此,在进行瓦楞纸箱包装设计时应侧重考虑运输和存储环境湿度对纸板强度的影响。试验方法可为包装行业在流通储运过程中考虑温湿度差异而以类似纸板为材料进行纸箱设计时提供参考依据。     

Study of morphological characteristics on hydrophilicity‐enhanced SiO2/Nafion composite membranes by using multimode atomic force microscopy

Air‐breathing proton exchange membrane fuel cells (AB‐PEMFCs) have a great potential for commercialization owing to their simple mechanical configuration and low cost compared with traditional proton exchange membrane fuel cells (PEMFCs). However, AB‐PEMFCs perform worse than traditional PEMFCs owing to the omission of the humidifier and a poor air supply system. In this study, hygroscopic metal oxide materials with good water absorption characteristics were employed in a Nafion membrane without humidification to compensate for the lack of performance owing to low proton conductivity. Among the various metal oxide materials, mesoporous structured silica has been synthesized with Nafion to increase the water content in nonhumidified conditions. The local morphological variation and surface charge distribution on the pristine Nafion and SiO₂/Nafion composite membranes were analyzed by using multimode atomic force microscopy and force distance analyses. Several remarkable results were revealed, including considerable morphological changes and a locally separated water cluster network structure.     

AB纱的开发与研制

概述了AB纱的特点与用途，并着重介绍了涤粘AB纱的生产的关键点和主要工艺措施。     

Novel materials through stereocomplexation

Summary Both (–)- and (+)-poly(lactide) (PLA) crystallize into a stereocomplex with a melting point that is 50 °C higher than that of crystals of the same-handed enantiomers. According to Boyer et al. [Polym. Prepr., 36 (1995) 87] and Jiang et al. [J. Am. Chem. Soc., 117 (1995) 7037], alternating isotactic propylene-CO-copolymers (P(P-alt-CO)) also form a stereocomplex with a higher melting point (60 °C). Force-Field-simulated structures for both polymer systems were found to agree well with X-ray data, irrespective of whether they had a chiral or racemic packing. The almost similar results for both stereocomplexes indicate that they might form a mixed stereocomplex of (–)-PLA and (+)-P(P-alt-CO). In acetonitrile, both enantiomers of an AB block copolymer derivative, poly(lactide)-poly(ethyleneglycol) (PLA-PEG); were found to crystallize exclusively into a racemic lattice. The influence of racemic packing on self-assembly of the two-block copolymer was analyzed by atomic-force microscopy. An equimolar mixture of (–)- and (+)-PLA-PEG formed spherical particles through stereocomplexation, in contrast to chiral block copolymers that formed large crystal needles and long rods.     

Burden of disease attributable to air pollutants from municipal solid waste incinerators in Seoul, Korea: a source-specific approach for environmental burden of disease

Few studies have attempted to quantify the integrated health burden, incorporating both mortality and morbidity as these factors pertain to air pollutants, on the population in the vicinity of the incinerators. The aims of this study are to estimate the attributable burden of disease caused by incinerators in Seoul, Korea and to present an approach based on source-specific exposure for the estimation of the environmental burden of disease (EBD). With particular attention on the development of a measurement means of the source-specific, exposure-based population attributable fraction (PAF), we integrated air dispersion modeling, Geographic Information Systems (GIS), the population distribution of exposure, and the exposure-response relationship. We then estimated the PAFs caused by additional concentrations of four air pollutants (PM₁₀, NO_2, SO₂, and CO) emitted from four municipal solid waste incinerators (MSWIs) in Seoul in 2007. We, finally, estimated the attributable burden of disease, using the estimated PAF and the disability-adjusted life years (DALY) method developed by the Global Burden of Disease Group of the World Health Organization (WHO).The PAF for NO₂ to all-cause mortality was assessed at approximately 0.02% (95% CI: 0.003-0.036%), which was the highest among all air pollutants. The PAFs for respiratory and cardiovascular disease were 0.12% (95% CI: 0.01-0.16%) and 0.10% (95% CI: 0.04-0.16%), respectively. The sum of the attributable burden of disease for four pollutants was about 297 person-years (PYs) (95% CI: 121-472 PYs) when the incinerators observed to the emission standards. The attributable burdens of respiratory disease and cardiovascular disease were about 0.2% and 0.1%, respectively, of the total burden of respiratory disease and cardiovascular disease of Seoul citizens for the year 2007. Although the air emissions from one risk factor, an incinerator, are small, the burden of disease can be significant to the public health when population exposure is considered.     

LaNi_(3.15-x)Mn_xCo_(0.25)Al_(0.1)储氢合金结构及电化学性能

为了研究Mn替代Ni对AB3.5型储氢合金结构及电化学性能的影响,采用电弧炉熔炼制备LaNi3.15-xMnxCo0.25Al0.1合金。采用XRD、SEM等材料分析方法以及恒电流充放电等电化学测试技术,研究LaNi3.15-xMnxCo0.25Al0.1(0≤x≤0.3)合金的结构和电化学储氢性能。结果表明:LaNi3.15-xMnxCo0.25Al0.1(0≤x≤0.3)合金由多相组合形成,合金的主相为LaNi5和La2Ni7;随着Mn替代Ni含量的增加,LaNi5相中a轴和c轴以及晶胞体积增加;合金电极的最大放电容量有所升高,由x=0的238mA·h/g逐渐增加到x=0.3的277.1mA·h/g;高倍率性能随着Mn含量的增加先升高后降低,在x=0.2时合金的高倍率性能最佳。     

Optimization and design of inter-stage amplifier with wide output swing,high speed and high accuracy

To satisfy the design requirements of analog-to-digital converter （ADC） of high speed sampling system in an infrared focal plane array tester with 1024 × 1024 pixels, a first inter-stage amplifier of 12-bit 40- Msample/s pipelined ADC was designed with 0. 35 μm CMOS technology. On the basis of traditional two-stage amplifier, the cross-coupled class AB output stage and cascode compensation were adopted to improve the output vohage swing and bandwidth. Power dissipation was optimized with math tools. Circuit and layout design were completed. Simulation results show that the designed amplifier has good performance of 95 dB dc gain, ±2 V output voltage swing, 190 MHz bandwidth and 63° phase margin with feedback factor 1/4, 33 mW power dissipation and so on, which can meet the system requirements.     

熔炼掺杂对AB5型贮氢合金的结构和性能影响

为了探索一种新的掺杂方式对AB5型贮氢合金性能的影响,采用熔炼掺杂方法,研究了掺杂适量TiMn1.5合金（掺杂量为4％、8％的TiMn1.5）对成分为‰．La0.7Ni2.65Co0.75Mn0.1的AB5型贮氢合金的结构及性能影响。XRD测试结果证实：掺杂后合金的主相仍为LaNi5相,生成了少量（NiCo）2Ti相。（NiCo）3Ti相的出现对贮氢合金的气态和电化学贮氢性能都有不同程度的降低。合金电极的动力学测试结果表明（线性扫描法和交流阻抗法）：在0．5～2．5C的放电电流密度,掺杂前后的合金电极的反应速率均由电极表面电荷转移速率决定,掺杂4％TiMn1.5的合金样品电极的高倍率放电性能有一定的改善。在3C放电电流密度以上,电极反应速率均由氢扩散速率来控制,随着TiMn1.5的掺杂的增加,其合金电极的高倍率性能降低。     

轻质炭黑AB325在子午线轮胎气密层胶中的应用

介绍轻质炭黑AB325在子午线轮胎气密层胶中的应用。结果表明,炭黑AB325含有的17%的低挥发性沥青质起增塑剂和助分散剂的作用,在缩短胶料混炼时间的同时不影响其它配合剂的分散,大大降低混炼能耗;炭黑AB325用量为10份时,胶料的综合物理性能较佳,气密性改进效果较好;胶料成本降低3%。