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1.
The assessment of water security is an important content in the security management of water resources due to the fact that the state of water security directly affects both the sustainable development of regional economy and the improvement on the living quality of mankind. Grey associative analysis is introduced and applied to assessment of water security on the basis of grey characteristics of the assessment index system of water security. As a case study shows, grey associative analysis is used for evaluating water security of some provinces in China, and the satisfactory assessment results are obtained. The sequence of provinces in China with regard to water security from good to poor is obtained and, moreover, the water security level of each region is also confirmed. The results obtained accord with the actual state of each region. They are of practical significance and can be used to guide the management of regional water security and a sustainable development of the economy therein. At the same time, the results demonstrate that grey associative analysis provides a new method for assessing water security  相似文献   

2.
The differential pulse voltarametric ( DPV ) method with a glassy carbon electrode was used for the determination of 3,3‘ 5,5‘-tetramethy lbenzidine ( TMB ) , o-tolidine and benzidine in the acidic media. The pulse amplitude, interval time and scan rate of DPV are optimized to be 50 mV, 0.5 s and 10 mV/s, respectively, The peak current is proportional to the concentration of TMB and its analogues, the linear range is from 10^-8mol/l to 10^-4 mal/l, The electrochemical behaviour of the compounds is discussed, The chemical poisons can be determined directly, or indirectly by the extraction in the waste water of chemical industry and laboratory,  相似文献   

3.
The assessment of water security is an important content in the security management of water resources due to the fact that the state of water security directly affects both the sustainable development of regional economy and the improvement on the living quality of mankind.Grey associative analysis is introduced and applied to assessment of water security on the basis of grey characteristics of the assessment index system of water security.As a case study shows,grey associative analysis is used for evaluating water security of some provinces in China,and the satisfactory assessment results are obtained.The sequence of provinces in China with regard to water security from good to poor is obtained and,moreover,the water security level of each region is also confirmed.The results obtained accord with the actual state of each region.They are of practical significance and can be used to guide the management of regional water security and a sustainable development of the economy therein.At the same time,the results demonstrate that grey associative analysis provides a new method for assessing water security quantitatively but needs a further study.  相似文献   

4.
Before clinical application of a new source, the dosimetric parameters of the source should be accurately determined. This work is dedicated to the Monte Carlo method to calculate dosimetric parameters as recommended by the American Association of Physicists in Medicine (AAPM) TG-43 guidelines for model ADVANTAGETM palladium-103 source and, through comparison with data from another published report for the same source, presents a suggested dataset for clinical applications. From these calcula- tions, tables are presented for the radial dose function and the anisotropy function of palladium-103 brachytherapy source. The dose rate constants are found to be 0.671 (cGyh-1U-1) in liquid water and 0.673 (cGyh-1U-1) in Solid WaterTM. And the anisotropy constants in liquid water and Solid WaterTM are found to be 0.864 and 0.865 respectively. Comparison with the previous study shows that our results of dosimetric parameters are in good agreement with those measured and calculated by Meigooni et al. (2006) both in Water and Solid Water^TM.  相似文献   

5.
Human centred robotics (HCR) concerns with the development of various kinds of intelligent systems and robots that will be used in environments coexisting with humans. These systems and robots will be interactive and useful assistants/companions for people in different ages, situations, activities and environments in order to improve the quality of life. This paper presents the autors‘ current research work toward the development of advanced theory and technologies for HCR applications, based on inspiration from biological systems. More specifically, both bio-mimetic system modelling and robot learning by imitation are discussed respectively, and some preliminary results are demonstrated.  相似文献   

6.
To study the feasibility of treated water being used as rinsing water with CP/ED (chemical precipitation/ electrodialysis) system, the relation between concentration of Cr (Ⅵ) and conductivity of water is investigated, the effect of electrodialysis (ED) for different wastewater is also studied. And several parameters of importance that are relevant to the process are identified. Analysis of ICP (Inductively coupled plasma) and IC (Ion chromatography) shows that the main reason of conductivity increase in CP treated water is the increase of Na+ and Cl- ions. The 93.8%-100% of ions from wastewater both in ED and CP/ED systems was removed successfully. The results of experiments indicate that the CP/ED system is a feasible method for electroplating wastewater treatment, the CP/ED system used as a way of wastwater is not only in favour of environment, but also economic beneficial to achieve.  相似文献   

7.
The differential pulse voltammetric (DPV) method-with a glassy carbon electrode was used for the determination of 3,3' 5,5'-tetramethy lbenzidine (TMB), o-tolidine and benzidine in the acidic media. The pulse amplitude, interval time and scan rate of DPV are optimized to be 50 mV, 0. 5 s and 10 mV/s, respectively. The peak current, is proportional to the concentration of TMB and its analogues, the linear range is from 10~(-6)mol/l to 10~(-4)mol/l. The electrochemical behaviour of the compounds is discussed. The chemical poisons can be determined directly, or indirectly by the extraction in the waste water of chemical industry and laboratory.  相似文献   

8.
A 368- water molecule structure I gas hydrate, encased by the number of helium (He) molecules ranging from two to twenty-two, are calculated by molecular dynamical simulations. The potential TIP4P (transferable intermolecular potentical with four sites) is used for water interactions and Lennard-Jones for He-He and He-water interactions. He molecules do not affect the water lattice and can stabilize the hydrate when their concentration is small. A trough signature of He encased is found at 80~90 meV in the phonon density of states. He molecules prefer to be more off-center in 51262 cages. Heavier isotope He are energetically favorable to be filled in cages.  相似文献   

9.
The existing textbook used in Intensive Reading class in English Department is not satisfactory according to an investi- gation made by the authors.Some investigations show:the texts are too easy,and monotonous both in content and style. Due to this,teachers also have the difficulty to teach this course in an interesting way.So suggestions should be made both on the change of textbook and teaching methods.Now we have to confront with an urging task:prosperity of textbooks is necessary and significant in course design and teaching reform.  相似文献   

10.
The transfer of Sr~(2+) and Ba~(2+) ion, facilitated by 18-Crown-6 present in the aqueous phase, and of succinylcholine ion at w/nb interface were investigated by semi-differential cyclic voltammetry. A good polarographic curve of succinylcholine ion dissolved in water was obtained in the system of 0.01 mol/l LiCl (w)——0.01 mol/l TBATPB (nb). The peak current is directly proportional to the concentration of SC~(2+) ion. It can be used for the determination of SC and the detection limit is 1.05×10~(-5) mol/l.The apparent D~w and D~(nb) have been estimated. The transfer of Sr~(2+) and of Ba~(2+) at the interface are facilitated by 18-Crown-6 present in the aqueous phase and the peak current is directly proportional to the concentration of 18-Crown-6 in water. This method can be used for the determination of the complexing agent and for the stability constant of the complex formed in the aqueous phase.All the experimental results are in keeping with the theoretical.  相似文献   

11.
A novel amphiphilic ABA type triblock copolymer with well-defined glycopolymer segments was successfully synthesized via the atom transfer radical polymerization (ATRP) technique, using a bromo-terminated difunctional polysulfone as macroinitiator. The difunctional polysulfone macroinitiator was prepared by esterifying the phenolic end groups of polysulfone to aaloesters. This macroinitiator was then used to initiate the polymerization of a glucose-carrying monomer, 3-O-methacryloyl-1,2:5,6-di-O-isopropylidene-D-glucofuranose (MAIpG), resulting an ABA type triblock copolymer. After acidolysis treatment, the isopropylidenyl groups of the protected sugar residues were removed, thus the amphiphilic ABA type triblock copolymer with well-defined glycopolymer segments was obtained. The polymers obtained were identified by FT-IR, ^1H-NMR, GPC, and TGA. The self-assembly behavior of the amphiphilic glycopolymer in selective solvent (e.g. DMF/H2O) system was also preliminarily explored. The resultant amphiphilic glycopolymer shows potential applications in the fields of controlled release and delivery of drugs, micro-reactors, nano-materials, medical devices, and SO on.  相似文献   

12.
Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was employed to achieve fast pyrolysis of biomass and on-line analysis of the pyrolysis vapors. Four biomass materials (poplar wood, fir wood, cotton straw and rice husk) were pyrolyzed to reveal the difference among their products. Moreover, catalytic cracking of the pyrolysis vapors from cotton straw was performed by using five catalysts, including two microporous zeolites (HZSM-5 and HY) and three mesoporous catalysts (ZrO2&TiO2, SBA-15 and AI/SBA-15). The results showed that the distribution of the pyrolytic products from the four materials differed a little from each other, while catalytic cracking could significantly alter the pyrolytic products. Those important primary pyrolytic products such as levoglucosan, hydroxyacetaldehyde and 1-hydroxy-2-propanone were decreased greatly after catalysis. The two microporous zeolites were ef- fective to generate high yields of hydrocarbons, while the three mesoporous materials favored the formation of furan, furfural and other furan compounds, as well as acetic acid.  相似文献   

13.
十八胺/羟丙基-β-环糊精包合物的制备与分析   总被引:1,自引:0,他引:1  
以羟丙基-β-环糊精(HP-β-CD)为主体,十八胺(ODA)为客体,采用研磨法制备了具有超分子结构的ODA/HP-β-CD包合物。考察了研磨时间、主客体物质的量比及包合温度对包合率的影响,确定了包合物的最佳制备工艺:研磨时间15min,主客体物质的量比2:1,热处理温度75℃。1H NMR和XRD衍射结果表明,ODA成功包合入HP-β-CD空腔中。通过相溶解度法研究了HP-β-CD在水中对ODA的增溶作用,结果表明HP-β-CD在水中对ODA增溶效果显著;经计算确定其包合常数为7877.69L/mol,形成的包合物结构稳定。  相似文献   

14.
This paper evaluated pulping performance of 3-year-old field-grown transgenic poplar (Populus tremula × Populus alba). The transgenic poplar with anti-sense CCoAOMT had an about 13% decreased lignin content, in which a slight increment was found in S/G ratio. Chemical analysis showed that the transgenic poplar had significantly less benezene-ethanol extractive than that of control wood, but no significant differences were found in contents of ash, cold water extractive, hot water extractive, 1% NaOH extractive, holocellulose, pentosans and cellulose. Fiber assay demonstrated that down-regulation of CCoAOMT expression improved the fiber quality in transgenic poplar. Kraft pulping showed that lower lignin in transgenic poplar led to remarkable improved pulp quality and increased pulp yield.  相似文献   

15.
分别采用分子动力学与半经验量子化学法,对羟丙基-β-环糊精(HP-β-CD)与十八胺(ODA)超分子包合体系的稳定构象进行了研究。以旋转挂片实验得到的碳钢腐蚀速率为基础,通过Arrhenius方程和过渡态理论,分析了该包合物在蒸汽凝结水中对碳钢的防腐蚀机理。热力学计算及俄歇电子能谱(AES)的结果显示,包合物中的ODA分子会克服其与HP-β-CD分子间非共价键作用,以吸附的形式在碳钢表面形成保护膜,且吸附过程符合Langmuir等温式;在流动的凝结水中,包合物中的 ODA分子以一定倾斜角度在碳钢表面吸附。  相似文献   

16.
李秉正  黎演明  吴学众  黄日波 《广西科学》2013,20(2):158-161,164
以酸性沸石为催化剂,催化葡萄糖脱水制备5-羟甲基糠醛(5-HMF).沸石催化剂采用固载磷钨酸(PW)和脱铝两种方法制备,固载PW方法用3种类型沸石:HY、MCM-41和HMOR,脱铝方法用HY型沸石,共制得产物PW/MCM-41、PW/HMOR、PW/HY、HY-D0.2和HY-D1.0,考察沸石结构、反应温度、葡萄糖与水质量比、催化剂与葡萄糖质量比对制备5-HMF的影响.结果表明,沸石固载PW后5-HMF的产率均有所提高,其中,以Y型沸石(HY)固载PW后(PW/HY)作为催化剂时5-HMF产率最高,为27.9%;HY特殊的结构对提高5-HMF的产率具有重要的作用.另外,提高反应温度有利于加快5-HMF的生成;葡萄糖与水质量比为3.0∶100时5-HMF产率最高,反应2.5h时达到30.4%,说明适当的葡萄糖与水质量比有利于5-HMF的制备.  相似文献   

17.
文中以程序升温脱附(TPD)和原位红外-程序升温脱附(IR-TPD)为主要实验手段,对5A分子筛的表面酸性特征及硫化促进剂在5A分子筛上的动态行为进行研究。结果表明:5A分子筛表面对胺类化合物表现出吸附能量高低不等的B酸、混合B酸和L酸、L酸及弱化学吸附位。对于吸附型缓释交联剂而言。有效的表面吸附部位为弱化学吸附位,且带有氢键吸附的特征。动力学计算结果表明:对于有效部位而言,不同的硫化促进剂由5A分子筛内孔表面脱出时,其动力学特征不同,但均与晶内扩散有关,其表观脱附活化能分别为75.4kJ/mol(二乙胺),63.6kJ/mol(环己胺)和69.9kJ/mol(乙二胺)。  相似文献   

18.
利用蒸汽热裂装置考察HM,HZSM-5型沸石型上n-C6的蒸汽热裂反应性能,并用TPD,IR及异丙醇分解反应测定其酸碱性,发现酸性Pentasil型沸的蒸汽热裂反应活性高,烯烃特别是乙烯收率较高,其中以SiO2/Al2O3比为60的HZSM-5沸石为最佳。  相似文献   

19.
Solar ultraviolet radiation B (UVB) is known to have inhibitive effects on phytoplankton photosynthesis. UVB light decreases rapidly with increasing depth in the water column and exerts different degrees of UVB inhibitive effects on phytoplankton photosynthesis. In this study, the objectives were to quantify effects of UVB on phytoplankton photosynthesis and quantum yield, and to examine UVB effects on phytoplankton photosynthesis when light varies. The insitu experiments were conducted in Da Ya Bay, which is a semienclosed area in the subtropical South China. The results showed a significant reduction of photosynthetic rates and quantum yield in the presence of UVB. Maximum photosynthetic rates (Pmax) and maximum quantum yield (Φmax) were 11%-22% and 17%-49% less under solar radiation with UVB than without UVB. A simplified model was developed to describe the UVB biologically effective fluence rate (E*inh) as an exponential decay function of depth. Light-shift experiments, in which water samples from the surface and at depth of 4 m were divided into several subsamples, and each subsamples were then incubated at different depths with and without UVB in the water column, showed that phytoplankton from the deeper water (4 m) had more inhibitive rates by UVB than that from the surface when exposed to the same light condition.  相似文献   

20.
The role of sediment resuspension duration in release of PAHs   总被引:3,自引:0,他引:3  
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants. Due to their low water solubility and high hydrophobicity, PAHs are rapidly sorbed onto particles and subsequently deposit in sediments once introduced into aquatic environment. In such a way, sediments become a huge sink for PAHs. During sediment resuspension, the potential exists for PAHs to be released from sediments into water. Sediment resuspension plays an important role in the transportation and fate of PAHs in the aquatic environment. In this study, release behavior of PAHs on Yangtze River sediment during resuspension was investigated using a particle entrainment simulator (PES). The role of resuspension duration on release of 16 PAHs was measured by resuspending sediment for 12 h at 0.2 and 0.5N/m^2, respectively. Results indicated that PAH concentrations in TSS increase over time with more increase of phenanthrene and 4-ring PAHs. Comparing with 0.2 N/m2 (30%), TPAHs concentrations in TSS demonstrated remarkable increase during 0.5 N/m2 resuspension (37%). Dissolved PAH concentrations increased throughout the duration with more increase of 2-3 ring PAHs (50%-88%). Dissolved PAH concentrations showed remarkable increase during 0.5 N/m^2 resuspension (50%). Moreover, PAH concentrations in overlying water throughout the duration of resuspension were higher than toxic effects threshold values in drinking water developed by WHO, which may cause toxic effect on ecosystem.  相似文献   

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