低维动态黑洞的熵     

LI Chen  SHEN Yougen   《中国科学院上海天文台年刊》2003,(1)

运用在砖墙模型方法的基础上发展起来的薄膜模型计算了 1 1维和 2 1维动态时空中的黑洞的熵。结果表明在低维动态时空中 ,黑洞熵仍满足Bekenstein -Hawking熵与面积的关系  相似文献   

Uptake and depuration of PAHs and chlorinated pesticides by semi-permeable membrane devices (SPMDs) and green-lipped mussels (Perna viridis)     

Bruce J. Richardson  Edmund S.-C. Tse  Sharon B. De Luca-Abbott  Michael Martin  Paul K.S. Lam 《Marine pollution bulletin》2005,51(8-12):975

Semi-batch seawater experiments were conducted to follow the uptake and release of selected PAHs (anthracene, fluorathene, pyrene and B[a]P) and organochlorine pesticides (α-HCH, aldrin, dieldrin, p,p′-DDT) in semi-permeable membrane devices (SPMDs) and green-lipped mussels (Perna viridis). Mathematical models were applied to describe the uptake and elimination curves of the contaminants for SPMDs, and kinetic parameters, such as uptake rate constants, and equilibrium triolein/water partitioning coefficients were calculated. SPMD data showed a good fit to estimate rate constant and partition coefficient equations, but only those contaminants which partitioned mainly in the dissolved phase (α-HCH and dieldrin) were well explained for mussels. Poor conformity of the other contaminants indicated mussels uptake by routes other than diffusion, such as ingestion of algae. An apparent equilibrium state was only noted for α-HCH in mussels. Aldrin was not detected in mussels in the first few days of exposure, indicating potential metabolism of this compound. B[a]P was not detected in the triolein of SPMDs, which suggests that the membrane may act as a reservoir. Loss of spiked B[a]P from the triolein was evident in a depuration experiment, which may indicate transfer to the membrane. Rate constants for mussels were higher than those for SPMDs, but the reverse was true for partition coefficients. Overall, mussels and SPMDs had similar uptake rates for all compounds in this study, excluding p,p′-DDT and dieldrin. Contaminant elimination took place more rapidly in mussels, implying that SPMDs are better candidates for detecting episodic discharge of organic contaminants.  相似文献   

Electrokinetic remediation of an electroplating site: design and scale-up for an in-situ application in the unsaturated zone   总被引：1，自引：0，他引：1  

S. Wieczorek  H. Weigand  M. Schmid  C. Marb   《Engineering Geology》2005,77(3-4):203-215

In-situ electrokinetic remediation of contaminated soils requires integrated approaches and adequately engineered setups to control relevant mass fluxes. Based on laboratory findings, this study presents the design of a pilot-scale remediation at an operating electroplating site. The fine-textured soil developed from Jurassic limestone exhibits a chromium, copper, nickel, and zinc contamination down to depths of more than 4 m. The feasibility of an electrokinetic remediation in the unsaturated zone was tested in a lab-scale experiment with subsoil material sampled at the site. The electrodes were placed in water-impermeable, ion-selective membrane wells. This construction allows the necessary watering of the electrodes, maintains unsaturated conditions in the soil compartment, and enables the transfer of contaminant ions into the wells. In addition, the soil is protected from pH changes caused by water electrolysis at the electrodes. The setup includes a watering and drainage system to compensate the electroosmotic water flux and impede desiccation of the anodic region. With a direct current of 70 V and an electric field strength of 2.2 V cm⁻¹, contaminant removal rates amounted up to 27% and 66% (w/w) of the initial zinc/copper and chromium/nickel concentrations. Copper, nickel, and zinc accumulated in the cathode well, while chromate species were enriched in the anode well. Given the successful lab-scale remediation, the pilot plant was designed for the in-situ treatment of a soil volume of 12 m³ below a production hall. A power of 500 V DC at a maximum current of 30 A is supplied by a transformer rectifier. This yields an electric field strength comparable to the lab-scale experiment and thereby similar contaminant transport velocities. A vacuum distillation unit is employed for process water reuse and to control electrolyte conductivity. To cope with chlorine gas generation at the anodes a gas absorber unit is employed. According to the lab-scale results, about 2, 9, 9, and 15 kg zinc, chromium, copper, and nickel, respectively, are expected to be removed from the field plot during an operation time of 10 months.  相似文献   

土壤石油污染物微生物降解机理与修复技术研究   总被引：13，自引：0，他引：13  

王红旗  陈延君  孙宁宁 《地学前缘》2006,13(1):134-139

较为系统地概述了土壤石油污染物的微生物修复技术和近年来石油烃代谢机理以及微生物细胞膜转运石油烃机理研究等方面的进展。文中着重讨论烷烃代谢途径、影响烷烃降解酶合成的阻遏物和激活物、芳香烃代谢过程和基因方面的研究,以及细胞膜结构的改变和石油烃的迁移等重要特性,最后从宏观系统的修复技术和微观分子学方面探讨微生物降解石油污染土壤的发展方向。  相似文献   

非对称天然沸石陶瓷膜的制备及其性能表征   总被引：1，自引：0，他引：1  

张学斌  胡晓翠  陈小丽  刘杏芹 《矿物学报》2007,27(1):6-10

利用天然沸石为主要原料,制备出具有过滤功能和重金属离子吸附功能的天然沸石非对称陶瓷膜。非对称膜中支撑体、中间层膜和顶层膜的平均孔径分别为6.6μm、0.6μm和0.1μm。非对称膜单位压力降(1 MPa)下的氮气通量和水通量分别为:24.69×103m3/(m2h)和1.87×103m3/(m2h);对重金属离子(铅离子)吸附交换能力为7.13 mg/g。  相似文献   

膜基—气体吸收耦合分离混合气中CO₂性能评价          下载免费PDF全文

陆建刚  郑有飞  连平  陈敏东 《大气科学学报》2007,30(6):881-884

在膜基—气体吸收耦合实验装置上,评价了疏水性PP(聚丙烯)微孔膜,活化MDEA(N-甲基二乙醇胺)溶液分离混合气中CO₂传质性能,研究了气液流速、吸收剂和混合气的浓度等因素对总传质系数的影响,采用阻力层关联方程模型预测总传质系数K_ov值。结果表明:活化MDEA溶液能提高总传质系数K_ov值,模型的计算值和实验值符合较好。  相似文献   

降阶模型在膜结构风振流固耦合分析中的应用     

孙芳锦  张爱社 《地震工程与工程振动》2011,31(3):59-64

针对膜结构风振流固耦合计算的强耦合分区法应用降阶模型,将降阶模型应用于耦合迭代运算过程.建立了流体域和结构域的降阶模型,给出了采用降阶模型进行强耦合分区计算的步骤.为了实现强流体域和结构域的强耦合,通过在耦合迭代过程中采用降阶模型的方式获得流体及结构的雅克比行列式,在每一时间步内采用降阶模型计算强耦合求解方法中的流体和...  相似文献   

低分子量氨基糖及其衍生物对角膜细胞生长影响的研究     

赵国燕  刘万顺  韩宝芹  梁晔 《中国海洋大学学报(自然科学版)》2011,41(3):52-56

体外培养兔角膜上皮细胞和基质细胞,采用显微观察和MTT相结合的方法分析低分子量氨基糖(包括壳寡糖(chitosan)、羧甲基壳寡糖(Carboxymethyl chitosan oligosaccharide)、羧甲基甲壳寡糖(Carboxymethyl chitin oligosaccharide)、N-乙酰氨基葡萄糖(N-acetyl-glucosamine))对细胞生长的影响。结果在0~1000μg/mL浓度范围内4种氨基糖对角膜上皮细胞和基质细胞均没有细胞毒性,且均能促进角膜上皮细胞的生长,以壳寡糖和羧甲基甲壳寡糖效果最佳,二者与对照组相比均具有显著性差异(P<0.05)。壳寡糖、羧甲基甲壳寡糖和N-乙酰氨基葡萄糖能明显促进角膜基质细胞的生长,与对照组相比具有显著性差异(P<0.05),其中壳寡糖的促进作用最明显。提示低分子量氨基糖可适用于角膜细胞促生长的培养,为壳聚糖衍生物材料用于眼科研究提供一定的实验依据。  相似文献   

O-羧甲基壳聚糖的制备及其结构表征     

王钦权  王远红  吕志华 《中国海洋大学学报(自然科学版)》2011,(Z1):356-358,364

本文以壳聚糖为原料,采用苯甲醛选择性的保护壳聚糖C2位氨基的方法,制备了O-羧甲基壳聚糖(O-CMC)。采用红外光谱及核磁共振波谱法对产物结构进行了表征,确定了羧甲基化反应只发生在壳聚糖的O位。该方法制备得到的O-CMC的羧甲基度为42.2%,反应选择性好,步骤简单,产率高达85%。  相似文献   

2种海洋寡糖对大麦种子萌发和生理特性的影响     

王婷婷  赵丽  夏萱  王鹏  江晓路 《中国海洋大学学报(自然科学版)》2011,41(11):61-66

本研究应用具有不同电荷性的褐藻寡糖(ADO)和壳寡糖(COS)处理大麦种子,探索在相同条件下不同浓度的海洋寡糖对大麦幼苗生长情况及生理特性的影响。生长指标包括苗长、根长、苗重及根重,以及对大麦种子淀粉酶活力和叶绿素含量的影响。试验结果表明:当ADO和COS处理浓度分别为0.5%和0.025%时,大麦的各项生长指标、种子淀粉酶活力及叶绿素含量均达到最大值,与对照组相比显著增加(P<0.05)。2种海洋寡糖均是具有独特生理活性的分子片段,分子量大小相近,但基于2种寡糖分子结构的不同,造成在对大麦的促生长方面存在差异性,为以后2种海洋寡糖的合理开发利用提供了参考。  相似文献