Based on the chlorinated organic compounds pollution existed in underground water of China, Zero-Valent-Iron (ZVI) technology is employed for the removal of four representative halogenated organic compounds (HOCs) (tetrachloroethylene, PCE; tricholoroethylene, TCE; tetrachlormethane, TCM; and chloroform, CT). The results indicated that the reduction rates of four target compounds, of which the initial concentration is 400 μg/L, negatively correlated with the size of Zero-Valent-Iron particles. The reduction kinetics of the targeted HOCs were all well fitted with the Pseudo-firstorder kinetics, and the ranking of obtained first order rate constants (K) among different particle sizes was K_20nm>K_100nm>K_10μm>K_100μm. Comparing K among four target HOCs, the reduction rates of chlorinated methane (CT, TCM) are higher than chlorinated ethylene (PCE, TCE), and highly chlorinated HOCs (PCE, CT) were degraded more easily than lower one (TCE, TCM). pH of aqueous solution all increased along the chlorinated compounds reduction which was raised by the reaction between ZVI and water. The oxygen in water consumed the ZVI particle either and competed with the surface adsorbed chlorinated compounds. In summary, Zero-Valent-Iron proved to be an efficient technology for typical HOCs removal, which can be considered as a promising process added in the beginning part of drinking water treatment plant.

The authors successfully generated pulsed molecular beams with high repetition rate by using a cantilever piezo valve, and the highest repetition rate could reach 3 kHz. The interaction between intense femtosecond laser fields and nitrogen molecular beams were studied, in which the molecular beams were produced by cantilever piezo valve. Strong fluorescence emissions, which could be assigned to N2 +(B-X), were observed. The performance of pulse valve was characterized based on the measurement of the fluorescence emission as a function of the repetition rate and the time delay of the pulsed valve. The results demonstrate that pulsed molecular beams can be generated with high quality and high repetition rate. The combination of such pulsed molecular beams and high-frequency kHz femtosecond lasers will promote the experimental study of molecular dynamics driven by intense femtosecond laser fields.

This study investigated the consumptions of HCFC-22 from 1989 to 2007 in China according to the end-use data from HCFC-22 related sectors including air-conditioning, industrial and commercial refrigerant, foam and chemical sectors, and calculated the HCFC-22 emissions from the correspondent sectors by using the bottom-up approach. In line with the accelerating process of HCFCs phaseout schedule and the development plan of related sector in China, the consumptions and emissions of HCFC-22 were estimated for the next 20 year. These results can be used for China’s phaseout plan of HCHF-22.

Different views of software architecture in UML diagrams are presented. It shows how UML can be used to model different aspects of software architecture. The semantics of UML diagrams are expressed in the notation of Communication Sequential Process(CSP). Different view models of software architectures are linked together based on the CSP semantics. The issue of refining such architectural specifications is also discussed, where software architectures can be refined in a manner that preserves desired system properties.

Function approach in autobiographical memory research and the results of research on the neural mechanism of autobiographical memory were summarized. New approach finds that autobiographical memory has self, social and directive functions. Research on its neural mechanism shows that autobiographical memory is located in temporal lobe and hippocampus. However, there is great inconsistency between the results of these two fields: neuropsychology research finds that autobiographical memory is mainly the function of right temporal lobe and hippocampus while brain imaging research shows that the primary activation occurrs in left temporal lobe and hippocampus during autobiographical event retrieval. There is no discussion or explanation about this inconsistency yet. Given the small number of neuroimaging studies and its inconsistent data, it would be better to compare the results gathered in the two different fields when there are more neuroimaging studies in the future.

Based on the brief description of the principle of Σ-ΔADC and analyses of modulator's noise characteristics, the Top-down design method of modulators is introduced. Then, combining with practical requirement, this paper focuses on the discussion of designing the analog circuits in a Σ-Δ modulator. Some key of design, circuit details and simulation results are also presented.

The numerical simulation of axisymmetric two-dimensional shock tube is studied, which has a conical convergent section, and its driving gas is the hot product of hydrogen oxygen detonation. Finite volume TVD scheme is adopted and the mesh is local orthogonal. The primitive equations are Euler's equations of multi-component flow. The new method of eliminating numerical oscillation at the interface of two materials is extended to two dimensions (2D). The mechanical character of this shock tube is analyzed.

When specifying and designing computer network protocols, it is convenient to use an abstract synchronous communication mechanism. In practice, however, asynchronous communication mechanisms cannot be avoided. This paper presents a formal approach, based on Hoare's Communicating Sequential Processes (CSP) and some theoretical results, to the specification and design of protocols which ensure the correctness of the protocols regardless of the communication mechanism used in implementation. The Alternating Bit (AB) protocol is used to illustrate our results.