浅析国际直接投资自由化进程中的中国外资政策

随着全球经济一体化的演进，国际直接投资日趋自由化流动。国际直接投资自由化的兴起在全球经济的增长和国际分工深化的进程中发挥了越来越重要的作用。我国是利用国际直接投资的大国，目前正处于向市场经济转轨的关键时期，经济体制和市场结构还不完善，如何在确保国家经济安全的前提下，推进国际直接投资自由化进程，积极合理地扩大引资规模，应成为人们关注的焦点问题。因此，本文试图探寻国际直接投资自由化的经济机理，总结出国际投资自由化的有效制度安排对现行制度进行调整，以期更好地把握和指导我国改革开放实践及进一步融入国际直接投资自由化进程。     

试用投资者情绪理论解释中国封闭式基金的价格变动

封闭式基金的折价交易是国内外基金市场的普遍现象,而传统经济理论在解释封闭式基金折价现象方面的失败对"市场有效性假说"提出了质疑.当我们在界定了"噪声交易者风险"的内涵和简单介绍了DSSW模型之后,对中国封闭式基金折(溢)价做出了一个尝试性的解释.     

马岭河峡谷漂流探险生态旅游开发研究

生态旅游已成为国内外旅游业中的一种时尚，漂流探险生态旅游由于其自身的特殊性，已逐渐成为生态旅游者中勇敢者最富旅游体验的项目之一。本文对贵州马岭河峡谷国家级风景风胜区的漂流探险生态旅游的开发优势、劣势条件进行了探讨，提出了对其开发规划的一些具体措施和对策。     

FDI在我国技术溢出效应的局限性及因应策略

利用索洛刺余模型对FDI在我国的技术溢出效应进行分析和实证检验，结果证明：在我国FDI的溢出效应并不明显。以溢出效应三个途径作为切入点，通过对导致溢出效应不明显的原因进行分析、实证检验，表明我国FDI的技术溢出效应存在局限性。如何克服这种局限性以提高内资企业的技术水平则是值得研究的课题。     

专利保护与技术创新关系的再思考

通过授予新技术以私人产权,使得作为公共物品的新技术可以通过市场的手段由私人部门提供出来,这是专利制度的本质,它总体上比政府奖励制度更有效率.然而,经典的专利经济学高估了专利制度对创新的促进作用.在一个技术进步加快的时代,累积性创新成为常态,更强的专利保护很可能会阻碍技术的进步.作为后发展国家,往往只能进行后续的跟进创新,较窄的专利保护宽度和较弱形式的知识产权保护更有利于创新能力的培养.     

有压隧洞弯曲段洞壁水流作用力分析

水资源的开发和水能利用与隧洞工程建设密切相关,尤其是有压隧洞运行过程中的水力对弯曲段洞壁的作用力,直接影响隧洞的可靠性和安全运行。为此,通过对国内外有压隧洞运行过程中产生问题的分析和总结,发现对有压隧洞出流段水力分析不足是产生上述问题的原因之一。文中利用伯努力方程和动量方程建立了隧洞弯曲段水流与隧洞壁的相互作用模型,导出了洞内水流和洞壁作用力分别与洞径、洞轴线曲率半径及隧洞进出流夹角的定量关系。从而为水利隧洞洞线规划、洞径和洞口进出流夹角的确定提供了有益参考。     

上海市日供水量与气象要素的相关性分析及预测模型的建立

基于上海市2010-05-2013-12日供水资料和气象观测资料,利用数学统计方法分析日供水量与气象因子的关系,并建立日供水量预报模型。结果表明:一年之中,日供水量大体呈现"单峰单谷"的波动特征,夏季(7、8月份)日均供水最多,冬季(2月份)最少;日供水量具有显著的节假日效应;除降水外,日供水量与其它气象因子均有显著的相关性,且夏半年相关系数明显高于冬半年;日供水量与温度的关系最为密切,且与前一日最高温度的相关系数最高,同时,当温度大于20℃时,日供水量对于温度变化的响应极其敏感;供水预报模型精度较高,可为城市用水规划、合理调度的气象服务保障提供科学依据。     

Removal of endocrine disrupting chemicals in a large scale membrane bioreactor plant combined with anaerobic-anoxic-oxic process for municipal wastewater reclamation

The removal of eight typical endocrine disrupting compounds (EDCs) in a full scale membrane bioreactor combined with anaerobic-anoxic-oxic process (A(2)/O-MBR) for municipal wastewater reclamation located in Beijing was investigated. These EDCs, including 4-octylphenol (4-OP), 4-n-nonylphenol (4-n-NP), bisphenol A (BPA), estrone (E1), 17α-estradiol (17α-E2), 17β-estradiol (17β-E2), estriol (E3) and 17α-ethinylestradiol (EE2), were simultaneously analyzed by gas chromatography/mass spectrometry after derivatization. The concentrations of eight EDCs were also measured in sludge of anaerobic, anoxic, oxic and membrane tanks to measure sludge-water distribution coefficients (K(d) values) as the indicator of adsorption propensity of target compound to sludge. The removal efficiencies of EDCs reached above 97%, except for 4-n-NP removal efficiency of 72%, 4-OP removal efficiency of 75% and EE2 removal efficiency of 87% in the A(2)/O-MBR process. The high K(d) values indicated that the sludge had a large adsorption capacity for these EDCs, and significantly contributed to removal of EDCs. Yeast estrogen screen assay was performed on samples to assess the total estrogenic activity by measuring the 17β-E2 equivalent quantity (EEQ), expressed in ng-EEQ/L. The measured EEQ value was markedly reduced from 72.1 ng-EEQ/L in the influent to 4.9 ng-EEQ/L in the effluent. Anoxic tank and anaerobic tank contributed to 80% and 37% in total EEQ removal, respectively.     

The fate of 14C-radiolabelled diclofenac and 4'-hydroxydiclofenac in membrane bioreactor treatment of wastewater

This study aimed at enhancing knowledge on the fate of diclofenac (DF), together with its main human metabolite 4'-hydroxydiclofenac (4'OHDF), during wastewater treatment by using a laboratory-scale membrane bioreactor (MBR). The reactor was fed continuously with non-radiolabelled diclofenac for a one month period prior to a single pulse of a 14C-radiolabelled solution of DF and 4'OHDF. The solution spike contained approximately 25% 4'OHDF and 65% DF, which corresponds to the ratio observed in municipal sewage, as well as traces of two other metabolites. The radioactivity was monitored for a total of twelve days in the various output streams. The calculation of the complete mass balance in the system demonstrated that the major part of the radioactivity left the reactor with the permeate (88.7%), while 2.1% was recovered in the excess sludge. Negligible amounts were recovered in the off-gas traps and on the membranes. Chromatographic analyses of effluent samples, by means of HPLC-MS coupled in parallel to a radiodetector, displayed a different pattern than the one of the spiked solution. It showed the occurrence of three additional metabolites.     

Treatment of linear alkylbenzene sulfonate (LAS) wastewater by internal electrolysis--biological contact oxidation process

Surfactant wastewater is usually difficult to treat due to its toxicity and poor biodegradability. A separate physico-chemical or biochemical treatment method achieves a satisfactory effect with difficulty. In this study, treatment of the wastewater collected from a daily chemical plant by the combination processes of Fe/C internal electrolysis and biological contact oxidation was investigated. For the internal electrolysis process, the optimal conditions were: pH = 4-5, Fe/C = (10-15):1, air-water ratio = (10-20):1 and hydraulic retention time (HRT)= 2 h. For the biological contact oxidation process, the optimal conditions were: HRT = 12 h, DO = 4.0-5.0 mg/L. Treated by the above combined processes, the effluent could meet the I-grade criteria specified in Integrated Wastewater Discharge Standard of China (GB 8978-1996). The results provide valuable information for full-scale linear alkylbenzene sulfonate wastewater treatment.