Enzymatic Degradation of Poly(l-Lactic Acid): Effects of UV Irradiation

Amorphous and crystallized poly(l-lactic acid) (PLLA-A and PLLA-C, respectively) films were prepared, and the proteinase K-catalyzed enzymatic degradation of UV-irradiated and non-irradiated PLLA-A and PLLA-C films was investigated for periods up to 10 h (PLLA-A) and 60 h (PLLA-C). The molecular weights of both the PLLA-A and PLLA-C films can be manipulated by altering the UV irradiation time. The enzymatic weight loss values of the UV-irradiated PLLA films were higher than or similar to those of the non-irradiated PLLA film, when compared with the specimens of same crystallinities. UV irradiation is expected to cause the PLLA films to undergo chain cleavage (a decrease in molecular weight) and the formation of C=C double bonds. It seems that the acceleration effects from decreased molecular weight on enzymatic degradation were higher than or balanced with the disturbance effects caused by the formation of C=C double bonds. After enzymatic degradation, a fibrous structure appeared on the spherulites of the UV-irradiated PLLA-C film. This structure may have arisen from chains containing or neighboring on the C=C double bonds, which were enzymatically undegraded and assembled on the film surface during enzymatic degradation. The results of this study strongly suggest that UV irradiation will significantly affect the biodegradation behavior of PLLA materials in the environment.     

The politics of carbon taxation: how varieties of policy style matter

ABSTRACT

The momentum achieved for unilateral carbon taxes in seven European countries is examined. Why is it that small countries, despite being vulnerable to forces of international competition, have been able to implement carbon taxes? A review of national experiences does not suggest that the share of fossil fuels in the energy mix defines the room for such taxes, or point to a strong role for traditional left-right ideology. Rather, it is deep-seated patterns of national policy styles with neo-corporatist traits, providing a protective device for the open economies of small countries, which condition the introduction of carbon taxes. The associated routines of decision-making offer coordination mechanisms for proactive macroeconomic policies in which carbon taxation can find a place. Parliamentary democracies with proportional representation, as is common in the smaller countries, provide access to government for political parties that pursue carbon taxation. These in turn sensitise larger political parties to climate concerns, as they benefit from institutionalised practices and routines for problem-solving and consensus-seeking.     

Taylor-Couette流场数值模拟及絮凝效果研究

通过流体力学中的Fluent软件模拟了Taylor-Couette反应器的速度矢量分布、湍动动能分布和有效能耗分布,同时实验研究了TaylorCouette反应器不同内筒转速下三氯化铁对高岭土悬浊液的絮凝效能.结果表明,内外筒环隙间存在亚微尺度的涡旋,当转速为30～60 r·min-时,涡旋形状闭合完整,相互分离,涡旋内部速度梯度较小,湍动动能k在0.00010 ～0.00023 m2·s-2的范围内,有效能耗ε在0.00057 ～0.00189 m2·s-3的范围内,絮凝效能达到最大(80％以上),湍动动能和有效能耗过大或过小均不利于形成完整闭合的涡旋,絮凝效能较差.     

射流式空气净化技术的实验研究

射流作为一种流体运动的特殊现象,其独特的界面和湍流接触性能可使传热和传质速率相比传统技术得到极大提高.将其应用于特定条件的空气净化(简称AJF),可产生一些传统技术不能达到的效果.利用频闪高速摄影技术对气-液两相射流的气速、液速特性进行研究,探讨了其相互作用,与传质及传热的关系,以及对空气中颗粒物、挥发性污染物净化性能的影响,重点研究和讨论了利用AJF方法对于油烟的净化效果.另外将对AJF空气净化技术从原理、技术路线、实验和应用等方面分别予以阐述.     

脉冲变频电磁场对水华鱼腥藻生长的效应

对脉冲变频电磁场作用下，扫描频率和磁感应强度的变化对水华鱼腥藻细胞活性和生长的影响进行了研究。结果显示，扫描频率从25~27 Hz增大到1~60 kHz时，磁场对藻细胞活性的抑制作用减小，但增大到60 kHz以上，磁场对藻细胞产生强烈抑制作用，累积水力停留时间4 min的藻样在48 h培养时间内已失去活性停止生长。扫描频率为50~100 Hz和1~60 kHz时，累积水力停留时间2 min的藻样，细胞受到磁场刺激生长加快；只有累积水力停留时间＞6 min，才表现出对藻活性的抑制作用。磁感应强度增大至120 G，磁场对细胞活性产生明显抑制作用，增大磁感应强度有利于对细胞活性和生长的抑制。     

Exposure of organophosphorus pesticides to turbulent diffusion flames

The development of effective fire-fighting strategies for warehouses storing large quantities of toxic chemicals depends on an understanding of the uncontrolled combustion of such toxics. This paper describes an experimental system for studying fires of this kind. Results are presented from a test programme involving fires with rates of convective heat release in the range 3–30 kW and four organophosphorus pesticides. This work on the combustion chemistry of toxic materials is part of a wider study, involving a number of laboratories, into other inter-related aspects of warehouse fires. The significance of the results for hazard assessment and emergency planning is considered.     

无井架附壁式爬模法在烟囱施工中的安全措施

附壁式爬模法在烟囱施工的安装、提升操作、高空拆除过程中的安全技术措施。     

Income Growth,Urbanization, Changing Life Style and Energy Requirements in China

Abstract

This paper aims to estimate the effects of changing life style and consumption demands driven by income growth and urbanization on increase of energy requirements in China, and estimate the impacts of improvement in household consumption on mitigating energy requirements towards 2020, based on input-output analysis and scenarios simulation approach. The result shows that energy requirement per capita has increased by 159% for urban residents and 147% for rural residents from 1995 to 2004. Growth in household consumption driven by income growth and urbanization may induce a successive increase in energy requirements in future. Per capita energy requirements of urban residents will increase by 240% during 2002–2015 and 330% during 2002–2020. Urbanization might lead to 0.75 billion ton of increment of energy requirements in 2020. About 45%–48% of total energy requirements in China might be a consequence of residents’ life styles and the economic activities to support consumption demands in 2020. Under low-carbon life style scenario, per capita energy requirements of urban residents may decline to 97% in 2015 and 92% in 2020 in contrast with baseline scenario. That implies that China needs to pay a great attention to developing green low-carbon life style in order to realize mitigation target towards 2020.     

东方艺韵——中国传统室内设计风格

中国传统的室内设计具有中国传统文化的一切特征，不管是空间的布局，还是装饰风格，都体现其内在的含蓄风格，在整体意境及设计理念上追求天人合一的自然和谐，同时也是传统建筑有机的组成部分。中国传统的设计元素越来越多地被当今世界设计师所借鉴。     

四川省青神县城景观风格的定位及其开发

一个城市的景观风格是该城市有形和无形环境的综合体现，是城市自然空间环境、城市文化内涵、民风民俗、建筑、古迹等城市构成要素的总和。从旅游发展的角度，通过对青神县城优越的地理区位、优美的山水城市空间环境、独特深厚的文化底蕴等优势条件的分析，提出其县城景观风格定位为“山水园林城市”的设想，并围绕突出“山、水、城、文化”等城市特色景观构成要素提出开发策略。