光伏太阳能电池生产过程中的污染问题

日益壮大的光伏产业正在为人类发展作出积极的贡献.采用光伏发电来代替传统的发电技术,将会减少89%的空气污染.然而,在这个倡导绿色环境的时代,光伏器件生产引起的环境、健康和安全（EHS）问题也日益引起社会各界的广泛关注.认清光伏产品在生产过程中污染的真相对维持光伏产业的可持续发展有着相当重要的意义.本文综述了常见太阳能电池的EHS问题,并提出了可以减少污染的有效途径;采用生命周期评估（LCA）方法进一步比较了各种太阳能电池生产过程中污染物的排放量数据.     

N-Doped Carbon Nanofibers Encapsulating CoO@Co9S8 Nanoparticles: Preparation from S-Rich Co32 Coordination Cluster Precursors by Electrospinning and Application for Superior Li-ion Storage

Thiacalixarene-supported Co₃₂nanoclusters encapsulated in polyacrylonitrile nanofibers(Co₃₂@PAN-NFs) by electrospinning have been utilized as precursors to fabricate N-doped CoO@Co₉S₈ carbon nanofibers(CoO@Co₉S₈@CNFs) for superior Li-ion storage. The S-rich Co₃₂ clusters capped by organic sheets afforded the well dispersed cobalt oxide/sulfide nanoparticles embedded in carbon nanofiber composites by direct calcination. The N-doped CoO@Co₉S₈@CNFs nanocomposites have been utilized as anode materials for lithium ion battery with the reversible capabilities being of 1051.8, 967.6, 894.7, 782.7, 669.5 and 525.4 mA·h/g at 0.1, 0.2, 0.5, 1, 2 and 3 A/g, respectively. The CoO@Co₉S₈@CNFs also showed a relatively high stable capacity of 551.7 mA·h/g at the current density of 1 A/g after 200 cycles of rate experiments. The as-obtained N-doped CoO@Co₉S₈@CNFs nanocomposites exhibited superior reversible capacity, rate performance, Coulomb efficiency(74.5% vs. 63.9%) and cyclic stability comparing with the CoO@Co₉S₈@C derived from simple annealing of Co₃₂ templates.     

聚乙烯亚胺修饰磁性纳米材料固相萃取-火焰原子吸收光谱法测定水样中痕量Mo(Ⅵ)

以聚乙烯亚胺(PEI)和二氧化硅包覆四氧化三铁(SiO2-Fe3O4)为原料,通过加热搅拌,制备了聚乙烯亚胺修饰磁性纳米材料(PEI-SiO2-Fe3O4)。利用红外光谱、扫描电镜和振动样品磁强计对PEI-SiO2-Fe3O4进行了表征。将PEI-SiO2-Fe3O4作为吸附剂应用于Mo(Ⅵ)的磁固相萃取,结合火焰原子吸收光谱,建立了一种检测水样中痕量Mo(Ⅵ)的新方法。该方法对Mo(Ⅵ)的线性范围为10~200 μg/L,检出限(LOD,S/N=3)为1.3 μg·L-1,定量下限(LOD,S/N=10)为4.3 μg/L,富集因子达172。应用建立的方法分析了环境水样、饮用水和工业废水中的Mo(Ⅵ),加标回收率为91.0%~110%,相对标准偏差(RSD)为0.90%~6.1%。该方法具有前处理速度快、灵敏、准确等特点,适用于各种水样中痕量Mo(Ⅵ)的检测。     

微弱日盲紫外电晕自动实时检测方法

针对目前商用日盲紫外/可见光双谱段电晕探测仪对故障的判定效率低且容易受噪声干扰问题,本文提出了一种微弱日盲紫外电晕自动实时检测方法。在分析电晕目标和噪声时间域统计特性的基础上,该方法利用电晕目标在时间域连续的特点,首先完成灰度图像二值化、形态学膨胀等预处理,其次将N帧连续图像累加后阈值化,最后进行特征提取,获取电晕位置、面积等特征信息,实现电晕的自动实时检测。在完成设备辐射标定的基础上,可立即回溯得到故障的光子计数参考值。建立了该方法的探测概率、虚警率数学模型。将其在高速数字处理平台TMS320DM642上实现并输入测试视频,结果表明:在典型参数情况下该方法单次检测虚警概率为2.85×10^-5,处理时间小于120 ms,可实现微弱日盲紫外电晕的实时检测。     

线性响应和两种态特定方法模拟AF350电子跃迁的溶剂效应

在极化连续模型框架下比较了线性响应与两种不同态特定方法计算的溶液中Alexa Fluor 350(AF350)分子激发能和光谱移动值的差异. AF350的第一激发态S0→S1电子跃迁属于π→π^*跃迁, 主要对应于最高占据分子轨道(HOMO)到最低空轨道(LUMO)的跃迁. 该分子激发态偶极矩大于基态偶极矩, 激发态时溶质溶剂相互作用比基态时更强, 随着溶剂极性增大, 会发生光谱红移的现象. 与实验值相比, 线性响应和两种态特定方法均高估了激发能, 其中以IBSF(Improta-Barone-Scalmani-Frisch)方法得到的激发能最小, 矫正的基态反应场方法(cGSRF)得到的激发能最大. 对于光谱移动值, 3种方法与实验值相比都偏小, 线性响应方法(LR)计算出的误差最大, 而IBSF方法得到的结果与实验值最吻合, 是预测溶液中AF350分子激发能和光谱移动值最准确的方法. 对比了Marcus传统理论和基于约束平衡的非平衡溶剂化理论的结果, 发现后者得到的激发能和光谱移动值更接近于实验值.     

TiO_2纳米阵列光阳极光电催化水分解研究进展

光电催化水分解制氢是目前解决能源危机与环境污染最理想的技术之一.设计和构筑高效的光阳极是实现光电催化技术实际应用的关键.在众多半导体光阳极材料中,TiO_2纳米阵列由于其快的电荷传输速率,高的光热稳定性,无毒和成本低等优点,已经被广泛用于光电催化水分解反应的研究.但是TiO_2本征的光吸收范围窄、光生电荷复合率高、表面水氧化动力学缓慢严重地制约了其太阳能-氢能转换效率.我们结合近年来国内外及本课题组的研究工作详细论述了TiO_2纳米阵列的改性策略,主要包括利用元素掺杂来拓展TiO_2的光吸收范围并提高导电性,构筑异质结促进光电极电荷的分离与转移,半导体敏化增加光电极的可见光吸收并促进电荷转移,表面处理用于增加表面水氧化反应速率.最后指出了该材料发展现状,并对其发展前景做出展望.我们为进一步提高TiO_2纳米阵列的光电催化水分解活性提供了理论指导和实践借鉴.     

Small World Effects in a Harmonious Unifying Hybrid Preferential Model Networks

Small world effects in the harmonious unifying hybrid preferential model (HUHPM) networks are studied both numerically and analytically. The idea and method of the HUHPM is applied to three typical examples of unweighted BA model, weighted BBV model, and the TDE model, so-called HUHPM-BA, HUHPM-BBV and HUHPM-TDE networks. Comparing the HUHPM with current typical models above, it is found that the HUHPM networks has the smallest average path length and the biggest average clustering coefficient. The results demonstrate that the HUHPM is more suitable not only for the un-weighted models but also for the weighted models.     

Sensitivity of Exponents of Three-Power Laws to Hybrid Ratio in Weighted HUHPM

The sensitivity of exponents of three-power laws for node degree, node strength and edged weight to hybrid ratio are studied analytically and numerically in the weighted harmonious unifying hybrid preferential model （HUHPM）, which is extended from an-weighted hybrid preferential attachment model we proposed previously [Chin. Phys. Lett. 22 （2005）719]. Our weighted HUHPMs plus the Barrat-Barthelemy-Vespignani model and the traffic-driven evolution model, respectively, are taken as two typical examples for demonstration and application of the HUHPM.     

Fluctuation of Quantum Information Density in Curved Time-Space

A dynamical equation for quantum information density （QID） in curved spacetime is presented. The related fluctuation of QID with quantum Einstein equation is also discussed, which reveals the measuring of the dynamical mutual information condition using a Gaussian quantum channel.     

CCD数码照相系统分辨率测试技术研究

介绍了CCD数码照相系统电视分辨率和空间分辨率的实验测试方法。以实验测试为基础定量地给出了数码照相系统可达到的分辨能力 (6 0 0TVL和 71条线 /mm)。在现有条件下 ,作者对传统冲洗金相显微照片同相同试样金相组织的电子金相照片进行了比较 ,并得到了满意的结果。