The historical development of urban water systems and their management concepts are reviewed, and the disadvantages and limits of the classical centralized urban water systems are analyzed, including the destroying of the urban water environment and the water cycle, the difficulties in wastewater treatment, the great financial demands and the long time of construction. The challenges and opportunities for the management of urban water systems are pointed out, including the more frequent drought and extreme precipitation, the intensification of urbanization and the demands of technological and administrative progresses. The concept for the management of tomorrow's urban water systems is expounded: viewing the management of urban water systems as a whole should be taken as the guidance; water saving must be practiced, and the global finance, technologies and experiences in the field should be shared; this concept provides us with inspiration for the management and reform of the urban wat...更多er systems in China.

It briefly reviews the development in the research area of environmental engineering material. In water treatment area, the progresses in newly developed adsorbent, coagulation accelerator and filter media are respectively introduced. The development in porous ceramic used to fix microorganism in biochemical treatment is also briefly introduced. Various sorts of catalyst used to purify auto exhaust are the main ways to control air pollution. In ecological restoration material area, sand-fixation material is briefly referred to.

The breeding and broad cultivation of semi-dwarf crop varieties in the 1960s and 1970s dramatically increased the grain production in the world, particularly in Asian countries, which was popularly recognized as the "First Green Revolution". Many factors have shown that the first green revolution has brought some environmental problems as well. The contradiction between the continuous increase of world population and the rapid decrease of farming land and water resources is calling forth a new green revolution marked with modern genetic engineering technology. To guaranty both the food security and environmental safety, the actions that China should take during the second green revolution were discussed.

Four phases were classified in terms of the relationship between human and rivers, including natural-cycled, engineering-regulated, pollution-controlled and ecological-rehabilitated phases. Based on the understanding of the relation between river health and river functions at certain stage, targets and principles for river regulation and rehabilitation were discussed. Note that most river systems were badly damaged due to over-exploitation. The idealized solutions to the river ecological rehabilitation should rely on the optimal analysis of the integrated system with multi-objective, multi-layer, multi-constraint characteristics. With reasonable consideration of river functions, thresholds and damaged levels, corresponding technologies and countermeasures for ecological rehabilitation of the damaged river systems were proposed.

To degrade sol-gel in aerospace wastewater, nano particles of titanium dioxide both pure and doped with Cu2+ were prepared using the sol-gel method and characterized by means of X-ray diffraction (XRD) and infrared absorption spectroscopy (IR). The particle sizes of TiO2 and Cu/TiO2 were uniform and the average diameters were approximately 29 nm and 2425 nm, respectively. The optimum content of doped-copper is 2.0%, the degradation rate of which is 57.5% following 1 h of UV illumination. The degradation rate is about 2 times higher than those of sol-gel TiO2. Influences of unsymmetrical dimethyl-hydrazine (UDMH) such as temperature, catalyst concentration on the degradation rate were studied. Experimental results indicate that when the temperature is 25 ℃ and TiO2 concentration is 0.6 g/L, the degradation rate of UDMH is best.

Bubbleless aeration of water was experimentally studied with a hollow fiber membrane. A high mass transfer coefficient was achieved, which is 6 times higher than that of conventional bubble aeration. Water flow rate and oxygen pressure are two major parameters that influence the oxygen transfer ability, and quantitative aeration can be achieved by controlling oxygen pressure. The bubbleless aeration using hollow fiber membrane is a promising technology.

As the pact of persistent organic pollutants (POPs) come into force, twelve of the commonly used POPs will be reduced or eliminated practically in the whole world. This paper discusses the progress in study of the characteristics of POPs, the criteria for identifying them, the commonly used kinds of them, the harmful of them, and how to deal with them. Based on the practical polluting condition and our national situation, suggestions are brought forward.

This article introduces the safety analysis method for two kinds of gas turbine high-temperature reactor (Prismatic-type HTR and Pebble-bed type HTR), and presents transient analysis results of emergency for GTHTR300.

A new type electric coagulation indoor air cleaning system, which had an excellent effect on particles elimination in indoor air, was introduced in this paper. The effect of electrode parameters on particles elimination by using electric coagulation indoor air cleaning system was studied in detail. The results showed that there was an optimum status between alternating current (440 V) and direct current (12 kV) in our experiments. The electrode parameters had a remarkable influence on small particles whose diameter was less than 1 μm, whereas the effect was indistinctive when the particle's diameter was in excess of 1 μm.

This paper researches and develops the straight strip-insert of special structure, which has elliptical teeth and broken edge on both sides. The teeth are the elements to drive the insert self-rotate under the action of fluidic power. With the broken edge, part of the fluid in tubes is led to flow spirally. So, this straight strip with elliptical teeth can remove the fouling on tubes wall automatically at low flowing velocity just like that twisted strip with oblique teeth. The convection heat transfer enhancement is much more than that of the plain twisted strip because of three factors: much eddy flow behind the elliptical teeth, fluid flow being changed into spiral flow, and the combination and separation of the spiral flow and axial flow. The experiments show that this new insert can be manufactured easily and has great comprehensive performance. It can work reliably at a low velocity of 0.5 m/s and make the heat transfer coefficient inside tubes be increased by 170%. The flowing r...更多esistance is in the range of industrial permission. Therefore, it has great significance of industrial application

The one-dimension projection algorithm, which is the steepest descent method, based on residual space for solving linear equations is analyzed in this paper. The definitions of long axis trap and trap depth are given. The geometrical feature of the algorithm is characterized. The method of perturbation based on residual series, which keeps residuals off the long axis trap, is presented in this paper. That is the multi-dimension projection method. The numerical experimentation shows that the method is superior to the present popular dominant algorithms.

Air quality in auto-cabin has become a major concern to people's health. The main influence parameters that affect testing results include temperature, humidity, vehicle age, air exchange rate, ventilation mode and environmental concentration, etc. These influence parameters and testing methods are discussed in this paper in depth, for the purpose of providing important reference to our country's present research about in-vehicle air pollution.

Concentrations of S as well as Fe and magnetic parameters' values (χ, χARM,SOFT,SIRM,χFD) were measured from 20 Xuzhou urban topsoil samples. The S concentrations are higher compared to that of background values in this region. A strong positive correlation between magnetic parameters (χ, χARM, SIRM, SOFT) and S, and a weak negative correlation between magnetic parameter (χFD) and S are exist. The pollution degree of SO2 in the atmosphere in the past may be assessed by means of magnetic monitoring due to the similar anthropogenic sources between magnetic minerals and S in Xuzhou urban topsoils as well as SO2 in the urban atmosphere.

A 3-dimension pump model which has the same size as the real pump is built in CATIA software.Tetrahedron element is uscd for the finite element method. The method overcomes the approximation of using shell element and thus makes the result more reliable. The strength of auxiliary reactor pump is calculated under seismic load and temperature field. The maxim Von Mises stress is 15.8 MPa, which is smaller than strength 132.825 MPa. The auxiliary pump is safe and fulfills the requirement of standard document.

The EGCs were proliferated and labeled with 5-bromo-2-deoxyuridine (BrdU), then transplanted into the acute damaged liver by CCL4 through tail vein. 2 and 4 weeks later, the liver was extracted and 10μm-cryostat continuous sections were obtained. The existing and differentiation of the transplanted cells were identified by immunohistochemistry, immunoflorescence double staining and PAS histochemistry for BrdU and hepatic-specific albumin (ALB), and the glycogen. The BrdU positive cells were found in the chronic damaged liver, some cells were BrdU and ALB double positive and PAS positive staining , the structures of damaged liver were also significantly improved. We demonstrated that the transplanted EGCs could be incorporated into the chronic damaged liver and differentiated into hepatocytes in this microenvironment, and its transplantation also could compensate for chronic liver failure. These results suggest that EGCs can be used for potential cellular hepatoplasty to treat damaged l...更多iver.

The better index of air temperature that can be used to distinguish the epidemic area from non-epidemic area of schistosomiasis using Geographic Information System (GIS), and the potential impacts of climate changes on the spatial distribution of schistosomiasis, were studied. The result shows that Oncomelania Hupensis has the possibility to move north if the other conditions that affect the survival of Oncomelania Hupensis meet, with the global climate warming and the carry-out of south-north water transfer project in China. Global climate warming will cause great challenges for the schistosomiasis control and the distribution of the Oncomelania Hupensis in the future.

In this paper we present a detailed analysis of the SESAME software system, which is used to make a diagnosis and forecast of the quantity of radioactive substances released into the environment should an accident occur at a pressurised water reactor. In addition, some modifications are made to the physical models, formulas, functions as well as some constants used in SESAME, so as to establish a special system for source term evaluation at Qinshan Phase II NPP.

It's essential for enterprises to employ information technologies nowadays. Successful implementation of complex IT requires a through understanding of the acceptance process of IT in organizations. After a review of the stage-models, the paper provides a new framework based on the punctuated equilibrium theory to model the acceptance process of information technologies in organizations. Focusing on the organizational change behavior, the new framework is more descriptive, predictive and directive than the traditional stage-models.

Nature reserves play an important role in the evolving challenge of maintaining a sustainable world. Visitors are one of the major causes of ecosystem damage. To ensure the sustainability of these ecosystems, the damage impact of visitors must be managed. First, this paper discusses the development of visitor management concept. In the beginning, one popular approach to visitor management is carrying capacity. However,carrying capacity is neither simple nor particularly useful. In the 1980s, visitor management frameworks, such as the Limits of Acceptable Change (LAC) planning system, was developed. The latter one is more effective than the former one in practice. Next,the theory of visitor management is explored in this paper. Alden suggested education programs aimed at changing visitor behavior might be more effective than solely through use limits. Limiting use is only one of many management options. Finally, an overview of eleven principles of visitor management is presented. These ...更多principles have emerged from researches on visitor impacts and from the management of protected areas to minimize those impacts. According to these principles and the practices in Baihuashan nature reserve, the paper put forward six principles of visitor management, which provide a sound basis for the systematic planning system for natural area visitor management in China.

From the point of view of hydrology, the cause of "August 1975" dam failure is mainly due to the low values of reservoir design floods rather than the low flood control standards; We have mainly learned from the failure: ① Scientific and technologic research shall not be leaning to one side, but absorb and accept whatever are good; ② Raising of flood control standards to a large extent would waste a huge amount of fund and not be feasible, and until today problems remain unsolved; ③ Learning foreign experience must be combined with the actuality in China, not by rote; ④ Major earth and rockfill dams must have "an emergency exit" (emergency spillway or emergency measures) in case super floods cause dam failures.

In order to minimize the environmental impact of nuclear spent fuel discharged from nuclear power reactors, researches of partitioning/transmutation and advanced nuclear fuel cycle are expanded in several nations. Separation of minor acitinides and long-lived fission products is the key process for such purpose. Compared to the current method for spent nuclear fuel treatment and disposal, the integrated process of reprocessing and high-level waste partitioning has distinct advantages, such as simplifying processing, reducing the secondary waste and improving economics. The integrated process is much more suitable for advanced nuclear fuel cycle. In this paper the recent advancement and progress on the integrated process of reprocessing and high-level waste partitioning are described.

Mg(OH)2 nanoparticles were prepared from Mg(OH)2·6H2O and ammonia by precipitation method. Different dispersing effects by using different surfactants were discussed. Mg(OH)2 surfaces were coated by organic flame retardant-THPC. Both the coated and uncoatedMg(OH)2 nanoparticles were characterized by SEM, TEM, FTIR, Zeta potential, DTA, etc.. The results showed that the Mg(OH)2 nanoparticles has been coated with THPC.

Technology is always the instrumentality to control nature in humankind's cognition and practice. But it is getting worse along with the global problems and the negative effects of technology application, and people begin to treat technology as the controlled object. This is the history development inevitable, is the resisting to the technology alienation, is the result that introspects to the person's subjectivity and the tool-reasonableness and is the latest stage of philosophy of technology development. It is advantageous to rebuild the broken correlations between culture and technology, shorten the future indetermination factor in economy, respond to the vocation of mankind's destiny in the future and promote the person's freedom and liberation, etc.

Moore's Law has difficulties in key technologies such as production cost and semiconductor microlithography,as well as in basic physical ideas. This paper gives comments on researchers' endeavors to defend the basic rationale in the fields of molectroics and quantum technology, and examines the instructive value of Moore's Law in the development of high-tech industries such as future computers, Internet and micro-electronics equips. A most important point is the basic idea of Moore's Law is still effective and applicable at present.