Modeling the current-voltage characteristics of thin-film silicon solar cells based on photo-induced electron transfer processes

Power conversion efficiency of p-i-n type macrocrystalline silicon (µc-Si:H) solar cells has been analyzed in terms of sequential processes of photo-induced electron transfer. The effect of the excitonic state on the charged carrier generation has been studied compared to a conventional scheme in which only charged carriers are taken into account for the operation of the solar cells. A numerical model has been developed to calculate current-voltage characteristics of solar cells on the basis of two types of charged carrier generation processes (exciton process and charged carrier process). The light trapping effect due to a textured back surface reflector (BSR) was embedded in the numerical model by using the effective medium theory in combination with the matrix method in the field of the electromagnetic theory of light. As an application of this modeling, it was found that the reported data of the power conversion efficiency were not explained by the conventional charged carrier process model and that the combined model of the charged carrier process with the exciton process well explains the performance of the p-i-n type μc-Si:H solar cells. In this way, the typical power conversion efficiencies were estimated to be 10.5% for the device (i-layer thickness: 1.8 μm) with the BSR (period: 600 nm; height: 250 nm) and 8.6% for the device with the flat reflector under the condition that the fractions of the exciton process and charged carrier process were 60% and 40%, respectively.     

溴化十四烷基吡啶对黑麦草吸收土壤中菲的影响

研究了澳化十四烷基吡啶(Myrlstylpyridinium bromide,MPB)对黑麦草吸收土壤中菲的影响.结果表明.由于MPB能显著增强吸附固定土壤中的菲,限制其从土壤固相向土壤水相迁移,从而可降低土壤水相中菲浓度,导致黑麦草吸收积累菲的程度降低.在两种不同菲污染水平的土壤中,MPB添加浓度为0～600 mg·kg-1时,黑麦草根系和茎叶中菲含量均随MPB添加量的增加而降低.当MPB添加浓度为600 mg·kg-1时.黑麦草根系菲含量分别为0.12 mg·kg-1和0.35 mg·kg-1,分别比对照低了77.0%和53.3%;茎叶中菲含量为0.12 mg·kg-1和0.26 mg·kg-1,分别比对照低了64.7%和50.9%.     

离子液体[C14mim]Br对大鼠亚慢性毒性的初步研究

研究了离子液体溴化-1-十四烷基-3-甲基咪唑盐([C_(14)mim]Br)对大鼠的亚慢性毒性.实验设立3个染毒组(2.5、5、10 mg·kg~(-1))和1个对照组,对大鼠经口染毒90 d后,分别考察大鼠的体重、血清生化指标、脏体指数、组织形态学的变化.结果表明,与对照组相比,染毒组大鼠的体重增长随着染毒剂量的增加而降低,肝脏/体重系数增大,其血清中碱性磷酸酶(ALP)、丙氨酸氨基转移酶(ALT)、天门冬氨酸转氨酶(AST)、直接胆红素(DBIL)和和球蛋白(GLB)水平均明显升高,A/G(ALB/GLB)、血清总蛋白(TP)值则明显下降.病理检查结果显示,染毒组大鼠的肝脏、肾脏及肺均有不同程度的损伤及病变.研究表明,[C_(14)mim]Br亚慢性染毒对大鼠的肝肾均有损伤,且其毒性呈一定的剂量依赖性.     

Definition of Planarian Mortality in an Acute Toxicity Test: A Case Study on Dugesia japonica Exposed to 1-Octyl-3-methylimidazolium Bromide

In order to define the mortality criteria of planarian objectively,a case study of Dugesia japonica exposed to 1-octyl-3-methylimidazolium bromide([C8mim]Br)was performed followed by a recovery culture.The results showed that defining planarian mortality in light of its body disintegration was appropriate.If the disintegrated tissue of a planarian was more than 1/4 of its body length,it would completely degenerate.However,a planarian would regenerate the lost tissue and return to normal after a few days’recovery culture if the disintegrated part was less than 1/4 of body length.Therefore,we propose to use body disintegration as the endpoint of planarian mortality,i.e.,1/4 body length degenerated is the critical threshold of mortality and survival of planarians when exposed to toxicants.This criterion could be adapted in the standardization of testing protocols and comparability of acute toxicity test or other toxicological research using planarian as the test animal.     

Testing of chemical substances for environmental effects—an important task for the chemical industry

Recently the heterogeneous reactions are increasingly recognised as significant in polluted areas. In this work the reactions of gases with solid alkali‐halide crystals at temperatures 200K and 300K were examined by using a recently proposed thermodynamic model (Varotsos et al., 1988) which provides the interconnection of entropy and enthalpy for various processes with well known macroscopic properties of the bulk solid.     

阳离子型可逆表面活性剂在膨润土上的吸附行为

研究可逆表面活性剂十一烷基二茂铁三甲基溴化铵(FTMA)在膨润土上的吸附机理,并与CTAB进行对比;同时考察土壤关键因子对FTMA吸附的影响.结果表明,FTMA与CTAB在膨润土上的吸附变化规律一致,饱和吸附量为66cmol/kg,约为膨润土1倍CEC,吸附机制主要为阳离子交换作用.不同温度下FTMA吸附等温线均可用Langmuir模型描述,吸附量随温度升高(298→318K),由280.6mg/g增大至350.8mg/g.吸附在8h达到平衡,吸附速率较CTAB慢,并符合准二级动力学方程,化学吸附是主要控制速率步骤.热力学参数计算得出,该吸附是自发吸热过程.随体系离子强度的增大,吸附量下降;共存阳离子对吸附有抑制作用,且影响程度大小为: Ca2+>K+>Na+; pH值对吸附影响较小;腐植酸(HA)的加入促进了FTMA的吸附.     

A semipermeable membrane equilibrator for halomethanes in seawater

An equilibrator for sampling the partial pressures of halomethanes in seawater was designed and built, incorporating semipermeable membrane tubing to carry the gas phase. The equilibrator was tested for its ability to equilibrate chloromethane, bromomethane, iodomethane, and CFC-11. The residence time required for these halomethanes to equilibrate in the tubing (30 to 60 s) was determined experimentally. In a laboratory test, concentrations calculated from equilibrator measurements and based on published solubility values were found to differ by 6% to 16% from concentrations measured with a purge-and-trap apparatus, but uncertainties in the solubility values are likely to contribute significantly to the differences. In a comparison at sea, no significant difference was found between the semipermeable membrane equilibrator and another, more conventional equilibrator, except a 1.3% difference for CFC-11. This study demonstrates the feasibility of using semipermeable membranes in this and related applications.     

光离子检测器测定大气中溴甲烷

用Ｔｅｎａｘ作为吸附剂捕集大气中的痕量溴甲烷,用气相色谱法和光离子检测器,对其进行检测,相对偏差为０．０５２１,最小检测限为１０ｐｇ。室内外大气中的浓度分别为２４×１０（－１２）（Ｖ／Ｖ）和７７．４×１０（－１２）（Ｖ／Ｖ）,污染在１０（－１１）（Ｖ／Ｖ）水平。     

Ozone decomposition under the irradiation of 253.7 nm in the presence of methyl bromide

In this paper the mechanism and kinetic of ozone decomposition under the irradiation of 253.7 nm UV-light were studied.The quantum yield of the ozone depletion in the presence of methyl bromide is further determined and a reaction model is provided to explain the experimental fact.     

Ozone decomposition under the irradiation of 253.7 nm in the presence of methyl bromide

ＩｎｔｒｏｄｕｃｔｉｏｎＯｖｅｒｐａｓｔｔｅｎ ｙｅａｒｓ,ｔｈｅｓｔｒａｔｏｓｐｈｅｒｉｃｏｚｏｎｅｄｅｐｌｅｔｉｏｎｈａｓｂｅｅｎｃｏｎｔｒｉｂｕｔｅｄｔｏｔｈｅａｃｔｉｖｅｃｈｌｏｒｉｄｅａｎｄｂｒｏｍｉｄｅ(Ｈａｒｒｉｓ,1995) .Ａｌｔｈｏｕｇｈｔｈｅｃｏｎｃｅｎｔｒａｔｉｏｎｏｆｂｒｏｍｉｄｅｉｓｍｕｃｈｌｅｓｓｔｈａｎｔｈａｔｏｆｃｈｌｏｒｉｄｅ,ｔｈｅｏｚｏｎｅｄｅｐｌｅｔｉｏｎｅｆｆｉｃｉｅｎｃｙｏｆｂｒｏｍｉｄｅｉｓ 50ｔｉｍｅｓｇｒｅａｔｅｒ (Ｈａｒｒｉｓ,1995;ＭｃＥｌｒｏｙ ,1986)…