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1.
Reservoir regulation process in the Yangtze River basin is mainly divided into two types of flood regulation and initiating benefit regulation. The present reservoir management system and operation mode are mainly for dealing with or coordinating of flood control and benefit initiation as well as benefit distribution among various beneficial functions. From the view point of river ecosystem protection, the current regulation mode has two kinds of problems : firstly, most of the reservoir regulation plans do not consider ecosystem protection at downstream of dams and needs of environment protection in reservoir areas; secondly, integrated regulation or management of water resources is ignored. It is very necessary to improve reservoir regulation mode, bearing problems faced by regulation of the Three Gorges reservoir and issues related to cascade development and regulation in Tuojiang and Minjiang River basins in mind. In accordance with the concept of scientific development, and the philosophy of "ensuring a healthy Yangtze River and promoting the harmony between human and water", taking flood control, benefit initiation and eco-system as a whole, this paper put forward the basic consideration to improve reservoir regulation as follows : on the basis of requirements of ecosystem protection at downstream of dams and needs of environment protection in reservoir areas, we should bring the functions of reservoir such as flood control and benefit initiation into full play, control the negative influence to the ecosystem at downstream of dams and the environment in reservoir areas in an endurable scope, and restore the ecosystem and the environment step by step. This paper put forward the relevant regulation process aiming at the idiographic problems such as protection of ecosystem at downstream of dams and environment in reservoir areas, protection of aquatic wildlife species and fish species, regulation of sediment and protection of wetland.  相似文献   

2.
Objectives define the boundaries of complex engineering system. It is a hard work to identify the specific objectives of a complex engineering system. The objectives system development needs a complicated process, from nix to prototype, and to final definition. The total process will cover the following course: from chaos to well-ordered; from qualitativeness to combination of quantitativeness and qualitativenss, then from qualitativeness to quantitativeness ( a recurrent process), expert experience and theoretical science, rationality and sensibility, synthesis analysis and meta-synthesis, routinization and non-routinization. Such process is explicit in phase development yet overlapped ; mutually confined yet mutually independent ; permeated conflicts yet pregnant in harmony. This article explores the complexity of Sutong Bridge' s objectives development and the process of meta-synthesis in the Sutong Bridge engineering.  相似文献   

3.
Positive development of renewable energy, saving and substitution of fossil energy, promotion of the energy structure adjustment are the inevitable strategy choices of China' s sustainable development. This paper discussed the China' s bioenergy resources status, development targets and technology development roadmaps. China has 136. 140 million hm^2 of marginal land, which distribute mainly in western and northern regions. There are 1 billion t of crop residues and forestry waste annually, and 300 million t can be used to produce different kinds of bioenergies. And organic waste and manure can generate 50 billion m3 of biogas. The discussed development target indicated that it can construct a biomass oilfield with the capacity of 100 million t/year and reduce 200 million t of CO2 emission by 2020. The bioenergy technology development roadmap indicated that the bioethanol mainly uses non grain starch and hemicellulose products as raw materials in the near-term (2006 -2010). The biodiesel technology will focus on the advanced production technology, FT diesel, liquefaction of biomass and raw material production technology.  相似文献   

4.
Cordyceps sinensis (Cs) or Dongchongxiacao in Chinese is a rare and precious medicinal mushroom. In this work, a Tolypocladium sp. fungus named Cs-HK1 was isolated from a natural Cs fruiting body, and its ultraviolet (UV), infrared (IR) and high-performance liquid chromatography (HPLC) spectra all exhibited high degrees of matching to those of natural Cs, indicating the similarity of chemical composition. A crude polysaccharide (PS) fraction isolated from Cs-HKI fungal mycelium showed significant antitumor activity, inhibiting melanoma tumor growth in mice. The PS-treated mice showed significantly higher serum interferon-y (IFN-y) level and higher proliferation rate of lymphocytes ex vivo than the control animals, suggestive of the immunomodulatory activity of the PS fraction. In cell cultures, the PS fraction caused a significant and dose-dependent inhibitory effect on the proliferation of two cancer cell lines, B16/neu mouse melanoma and MDA-MB-231 human breast cancer cells, but not on normal spleen lymphocytes in vitro. Most of these bioactivities of the Cs- HK1 fungus were comparable to or even greater than those of natural Cs. The results showed that Cs-HK1 fungus may be a functional substitute for the natural Cs in health food and herbal medicine.  相似文献   

5.
The near-surface freeze/thaw cycle in cold regions plays a major role in the surface energy budget,hydrological activity,and terrestrial ecosystems.In this study,the Community Land Model,Version 4 and a suite of high-resolution atmospheric data were used to investigate the changes in the near-surface soil freeze/thaw cycle in response to the warming on the Tibetan Plateau from1981 to 2010.The in situ observations-based validation showed that,considering the cause of scale mismatch in the comparison,the simulated soil temperature,freeze start and end dates,and freeze duration at the near-surface were reasonable.In response to the warming of the Tibetan Plateau at a rate of approximately 0.44°C decade-1,the freeze start-date became delayed at an area-mean rate of1.7 days decade-1,while the freeze end-date became advanced at an area-mean rate of 4.7 days decade-1.The delaying of the freeze start-date,which was combined with the advancing of the freeze end-date,resulted in a statistically significant shortening trend with respect to the freeze duration,at an area-mean rate of 6.4 days decade-1.Such changes would strongly affect the surface energy flux,hydrological processes,and vegetation dynamics.We also found that the rate of freeze-duration shortening at the near-surface soil layer was approximately 3.0 days decade-1lower than that at a depth of 1 m.This implied that the changes in soil freeze/thaw cycles at the near surface cannot be assumed to reflect the situation in deeper soil layers.The significant correlations between freeze duration and air temperature indicated that the shortening of the near-surface freeze duration was caused by the rise in air temperature,which occurred especially in spring,followed by autumn.These results can be used to reveal the laws governing the response of the near-surface freeze/thaw cycle to climate change and indicate related changes in permafrost.  相似文献   

6.
One of the important science requirements of monitoring atmospheric methane abundances from hyperspectral measurements is to establish a highly accurate retrieval algorithm.This paper aimed to describe a retrieval algorithm based on a series of sensitivity study with an effective and accurate forward model,which was applied to realize online calculation of absorption coefficient and backscattered solar radiance.The sensitivity study consisted of band selection,interference factors analysis,and retrieval model construction.The band selection analysis indicated that the 1.65 lm band(5,900–6,150 cm-1)associated with the 2.06 lm band(4,800–4,900 cm-1)retained more than 90%of the information content of CH4,CO2,and temperature,and more than 85%of that of H2O in the retrieval.Investigation of the interference factors showed that H2O,temperature,and CO2will cause unacceptable errors if they are not revised.This also showed that revising temperature and H2O with a profile model is more efficient than with a temperature offset and a H2O scale factor model.A preliminarily test using the Greenhouse gases Observing SATellite Level 1B spectral data indicated that most of the retrieval errors were less than 1%,which is acceptable for methane flux estimation.  相似文献   

7.
Integrating various resource advantages including location, land, coastline and waterway, Heng- sha, Shanghai will be the new space of strategic development in the future (especially after 2020). Inspired by marine economic development and continual establishment for new strategic space of coastal cities, in this pa- per we will take the strategic development direction of Hengsha new space into consideration when enlarging on the positioning of the new development space in Hengsha, which includes international logistic center (free har- bor and logistic transshipment center), modem port industry, high-end services, tourism, leisure, and recre- ation and ecological village in downtown area.  相似文献   

8.
In this work,we developed a facile and low-cost method with sufficient sensitivity for the quantitative determination of gold nanoparticles(GNPs)number concentration in water and fetal bovine serum solutions.The Au(III)digested from GNPs was reduced to Au(I)presumably by the thiol group of 2-mercaptobenzimidazole,then the Au(I)–thiolate complex was formed,the concentration of which is determined by absorbance at 300 nm.The number concentration of GNPs can be converted using microscopic images and simple calculations.The interference of serum can be avoided in this method.The limit of detection(LOD)of GNPs was calculated as 2.1 910-12mol/L in water solution and 1.3 9 10-11mol/L in fetal bovine serum(FBS)solution.This method provides a simple and fast way to determine the concentration of GNPs,which can be in carried out in the routine laboratory practice.  相似文献   

9.
To promote the construction of Shanghai international shipping center, the planneu new acepwatcr terminal construction in Hengsha pushes forward the innovation and breakthroughs of the existing port manage- ment system and building mechanisms. Through reviewing, analyzing, comparing and summarizing the suc- cessful experience of the major ports at home and abroad, market-oriented recommendations will be proposed in terms of effectiveness and feasibility, as well as the idea of"Shanghai Freeport".  相似文献   

10.
Biofuels are the current promising alternative to fossil fuels. However, the fluctuating food prices caused by oil price led to critics to biofuels. The paper surveyed biofuels production and grain production and consumption demand, and come to the conclusion that there was a little impact of corn ethanol on international food price, and there was no impact on China' s food prices. China has launched non-food biofuels development strategy to use marginal lands for growing hard crops, such as sweet sorghum, tuber crops, and switchgrass etc. to produce biofuels without any impact on food security in the future.  相似文献   

11.
With high effective screen-printing technique, a new triode field emission display (FED)with enhanced petaling cold cathode was fabricated. For enhancing the field emission performance,a series of improved measures was adopted in the fabrication course. Seen from the fabrication structure of enhanced petaling cold cathode,the bar conducting electrode and the petaling bottom electrode were fabricated with the sintered silver slurry on cathode glass faceplate. The luminescence image with green phosphor was displayed for the sealed enhanced petaling cold cathode FED. The measured results showed that the enhanced petaling cold cathode had good field emission performance. The enhanced petaling cold cathode FED possessed low turn-on electric-field of 1. 95 V /μm,large emission current of 1 389. 6 μA,and high luminance brightness of 1 520 cd /m2 .  相似文献   

12.
This paper presents a new method for the system identification of the channel roughness for the water di- version projects. According to the principle of hydraulics, the function relationship among channel roughness n, roughness height ks and hydraulic radius R is established, and then a linear model is deduced by means of the mathematical transformation to make use of the least square method for identification. Finally, based on the proto- type observation data from the South-to-North Water Diversion Project and considering the influence of channel lengths, cross-section shapes and bottom slopes, etc, a universal formula is obtained for calculation of channel roughness by the system identification.  相似文献   

13.
In order to improve the mechanical property and Cl-+S2-corrosion resistance of B15 copper-nickel alloy,Cu-15Ni-xRE(x:0-0.1%by weight)alloy was prepared by adding rare earth(RE)in melted Cu-15Ni alloy using metal mould casting method.Optical microscopy(OM),electronic tensile testing machine,X-ray diffraction(XRD),scanning electron microscope(SEM),and electrochemical testing system were used to analyze mechanical property,corrosion resistance property,and surface microstructure of different treatment samples.The results of OM and tensile testing show that the RE addition can effectively deoxidize the alloy melt and the microstructure of the alloy changes from coarse dendrite to small equiaxed grain.By addition of 0.05%RE,the tensile strength and elongation of Cu-15Ni alloys are improved from 294 MPa to 340MPa,and 8%to 33.5%respectively.The results of electrochemical testing show that the corrosion resistance of Cu-15Ni alloy is greatly improved by adding proper amount of RE,whereas excess addition of RE worsens the corrosion resistance.The optimum RE content was about 0.05%by weight.In comparison with the alloy without RE,the corrosion potential and corrosion current density of Cu-15Ni alloy containing proper RE decreased by about-0.28 V and 70A/cm2,respectively.  相似文献   

14.
A novel compression method for mechanical vibrating signals,binding with sub-band vector quantization (SVQ) by wavelet packet transformation (WPT) and discrete cosine transformation (DCT) is proposed.Firstly,the vibrating signal is decomposed into sub-bands by WPT.Then DCT and adaptive bit allocation are done per sub-band and SVQ is performed in each sub-band.It is noted that,after DCT,we only need to code the first components whose numbers are determined by the bits allocated to that sub-band.Through an actual signal,our algorithm is proven to improve the signal-to-noise ratio (SNR) of the reconstructed signal effectively,especially in the situation of lowrate transmission.  相似文献   

15.
Developing new techniques to remove and recover phosphorous simultaneously from wastewaters is very important for sustainable utilization of phosphorous resource and prevention of eutrophication. The feasibility of phosphorus bioaccumulation in a novel continuous alternating anaerobic /aerobic biofilter and benefits of such accumulation for its further recovery as magnesium ammonia phosphate (MAP) were studied. The system was operated for seven months and employed the atomic absorption spectrophotometer (AAS) method to analyze the distribution change of magnesium and calcium with phosphate in the biofilter during that period. The benefits of utilizing the biofilter system to accumulate phosphorous & magnesium and suppress calcium simultaneously to phosphorous recovery as MAP were explained with the aid of chemical equilibrium models. The improved phosphorus recovery from 42% to 82% was approved in the recovery experiments and the recovery products mainly as MAP were evidenced and characterized with scanning electron microscopy (SEM) . The study provides references for designing and operating the novel alternating anaerobic /aerobic biofilter for phosphorus bioaccumulation and recovery.  相似文献   

16.
A point on the distinction between design and science is given and the connotanons of aeslgn science are discussed in the paper. Design should be understood as the first step of all human' s purposeful activity, which is a daily behavior for everyone. Four laws are summarized, which describe the basic patterns of design and are the constituents of design science. They are the law of design based on existed knowledge, law of in- completeness of design knowledge, law of design centered on new knowledge acquirement and law of competi- tiveness of design knowledge. The four basic laws show the knowledge essence of design. To enrich the existed knowledge, to make it convenient to be used, to teach designers with high intuition and inspiration in picking useful elements of existed knowledge and shaping competitive ideas and to have strong new knowledge acquire- ment facility are the basic conditions of good designs. Study of design science will promote the structure of tra- ditional engineering education. An important conclusion is derived that there will be no successful innovation without good design.  相似文献   

17.
Facing the pressure of fossil energy exhaustion and environment pollution, people begin to search for clean and renewable energy to partly substitute fossil energy and realize sustainable development. As the fourth type of energy, biomass energy has many advantages : wide distribution, large quantity, being renewable, clean, storable and transportable and so on. By adopting thermo-chemical and biochemical technologies, biomass energy can be converted to high quality solid, liquid and gaseous energy products, and provide convenient heat and power energy for human being' s production and daily life. This paper presented the status quo of biomass power generation industry in China and also introduced briefly the future development models.  相似文献   

18.
PNP-type ligands showed very good property in the catalytic systems of PNP/Cr(Ⅲ)/methylaluminoxane(MAO)for ethylene selective tetramerization toward1-octene.In this research,two PNP analogues bis(diphenylphosphino)phenylborane and bis(diphenylphosphino)dimethylsilane have been synthesized and characterized.In combination with CrCl3(THF)3as active center and MAO as cocatalyst,these ligands produced a new catalytic systems for ethylene oligomerization to linear α-olefins with catalytic activities of up to 3.07 9 106g mol-1(cat)h-1.Herein,we report the effects of the reaction temperature,ethylene pressure,and the molar ratio of Al/Cr on the catalyst activities and product selectivities.  相似文献   

19.
After the Chang’e-2 spacecraft conducted a successful asteroid flyby,where is it flying to in interplanetary space?This question is answered via an introduction to the Chang’e-2’s flight trajectory after asteroid flyby that is termed Earth co-orbital motion.Based on preliminary analysis using the dynamical systems theory,Poincare′sections concept,and routine optimization techniques,it is now predicted that,from the point of view of orbital mechanics,Chang’e-2 is capable of returning to the vicinity of the Earth in no more than 20 a and might be recaptured by the Earth if appropriate orbital maneuvers are going to be exerted,either by itself or by another spacecraft that captures Chang’e-2.  相似文献   

20.
Lattice-Boltzmann equation(LBE)–Discrete element method(DEM)coupled simulation of a twodimensional gas–solid cross jet is performed,focusing on the gas-particle two-way coupling effect on heat transfer characteristics.The Reynolds number is 1000,and particle Stokes numbers are 10,25,and 50 under the same number flow rate of particles.The gas phase temperature field and particle distribution as well as the inter-phase heat transfer characteristics are studied and analyzed.The dominating effects,i.e.the mean temperature difference and mean heat transfer coefficient between the gas–solid phases,for the pre-and post-collision stages of the cross jets are illustrated respectively.The change of dominating roles is related to the dynamical response characteristics of particles.  相似文献   

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