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To achieve the precise motion of a 3-RRR compliant parallel precision positioning stage,a closed-form exact motion model was established and the optimized design of structure parameters was investigated.The Castigliano's second theorem was applied to establishment of the closed-form compliance model for the precision positioning stage.According to the structural characteristics of compliant parallel mechanisms,the system was divided into three symmetrical motion sub-chains.Combining the compliance equations of flexure hinge with the force transmission relations of mechanisms,the stiffness model of each sub-chain was obtained,and the stiffness of the entire system was calculated by summing the stiffness of three sub-chains in the same coordinate system.The proposed stiffness model took the hinge flexibility as the independent variables in the closed form.According to the flexibility matrix,the Jacobian matrix to reflect the relationship between input displacement and output one could be derived.By comparing the kineamatic model between theoretical analysis and FEA,the results show that the errors are within 1.0%~9.5%,which illurastrates that the proposed kinematic model is correct and precise.According to the closed-form Jacobian matrix,its sensitivity to structureal parameters was analyzed,then the design variables with greater impact on the kinematic properties were chosen.By taking the maxmium workspace as a target and the hinge strength,maxmium input forces,geometric dimensions and input coupling as the constrains,an optimal model was proposed.The results show that the optimized structural parameters can obtain more output displacements,and the proposed model can meet the design requirement.

Endogenous antimicrobial peptides are exciting candidates as new antibacterial agents due to their broad antimicrobia spectra, highly selective toxicities and the difficulty for bacteria to develop resistance to these peptides. Marine invertebrates, which rely solely on innate immune system for host defense, are the spectacular resources for new antimicrobial compounds. In order to seek for new effective antibiotics, tissue homogenate of Bullacta exarata was treatedwith trypsin, and was isolated following ultrafiltration, gel chromatography and reverse phase high performance liquid chromatography (reverse-phase HPLC). Antibacterial activities of the peptides purified from B. exarata were measured by the agar diffusion test and minimal inhibitory concentration (MIC). Three isolated peptides, BEP-1, BEP-2 and BEP-3, showed activity against Escherichia coli, Staphylococcus aureus and Bacillus subtilis. BEP-1 also showed activity against human pathogen strains (Staphylococcus epidermidis, E. coli and Methecillin-Resistant S. aureus). This research picked out three candidates for new effective antibiotics. Key words: Bullacta exarata, antimicrobial peptides, isolation and purification, antibacterial activity, minimal inhibitory concentration.

We examine the challenges to China's transition to a low carbon electricity system, in which renewable energy would play a significant role. China's electricity system currently lacks the flexibility in planning, operations, and pricing to respond to conflicting pressures from demand growth, rising costs, and environmental mandates in a way that simultaneously maintains reliability, decarbonizes the system, and keeps prices within acceptable bounds. Greater flexibility crucially requires the ability to more systematically and transparently manage and allocate costs. This will require re-orientating sector institutions still rooted in central planning, and strengthening independent regulation. Some of the necessary changes require fundamental political and legal reforms beyond the scope of energy policy. However, the system's flexibility can still be increased through the development of traditional planning and regulatory tools and approaches, such as an avoided cost basis for energy efficiency investments, more integrated planning to improve the coordination of generation, transmission, and demand-side investments, and a transparent ratemaking process. The judicious application of OECD electricity sector experience and skills can support these developments.

Background: Public health emergencies have a significant impact on the health of citizens, the local economy, and society as a whole. Currently, in many parts of China, there is a widespread lack of the knowledge and skills required for emergency preparedness and self-rescue. By carrying out targeted health education and intervention activities, and by popularizing the knowledge and skills in health emergencies, the abilities of citizens to respond to public health emergencies and protect themselves, reduce property damage, and eliminate unnecessary panic may be greatly improved. Objectives: The knowledge and skills of the public to respond to public health emergencies after an intervention in Sichuan province were surveyed. The conditions before and after the intervention were compared, and the effect of the intervention was evaluated. Methods: Four counties in Sichuan province were selected for baseline survey by means of a multistage random sampling method. Among the districts and counties, one of each was selected for baseline survey as an intervention group and another of each were selected as controls. After 1 year of intervention, respondents were selected from the intervention group by means of the method used for the baseline survey for effect evaluation. Results: After statistical analysis, it was shown that, after the intervention, the total awareness rate of knowledge to respond to public health emergencies increased from 42.6% to 58.4% among men and from 42.9% to 55.8% among women, both significant differences ( p < .001). It was also shown that the total awareness rates of the 18–35, 36–45, 46–60, and 60+ age-groups, respectively, increased from 44.5%, 43.7%, 42.2%, and 37.8% to 62.1%, 56.0%, 56.8%, and 51.9%, which were also significant differences ( p < .001). Intervention, educational level, occupation, discussion with the families, and disaster experience were the main influential factors for the knowledge and skills of sudden public health events. Conclusions: The study results show that, after the intervention in Sichuan province, the knowledge and skills of the public to respond to public health emergencies were significantly improved. It is also shown that health education interventions must be developed in accordance with geographical features, the educational level of the population, age characteristics, and other factors.

This paper investigates the influence on energy consumption by economic structure in China using panel cointegration and Granger causal test with panel vector error correction (VEC) model. The panel cointegration test reveals the long equilibrium relationship between energy consumption and economic structure in China. The Granger causal test with panel VEC model reveals the unidirectional causality from economic structure to energy consumption and the bidirectional causality between energy consumption and economic growth in the short and long run. The influence on energy consumption by economic growth is greater in the short run and the influence by economic structure is greater in the long run. Thus when the “energy saving and emission reduction” are in work in China, more attention should be paid to the measures involving the economic structure adjustment. The measures include decreasing the proportion of the high energy consumption industries and supporting the development of the service industries. Thus the target of “energy saving and emission reduction” will be achieved without influencing the economic growth.