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71.
Environmentally friendly green composites were prepared by blending Wheat gluten (WG) as matrix, dialdehyde starch (DAS) as filler and glycerol as plasticizer followed by compression molding of the mixture at 110 °C. The properties of the WG/DAS composite are compared with those of the WG/native wheat starch (NWS) composites. While tensile strength and strain at break decrease with increasing NWS content in the WG/NWS composites, a small content of DAS could improve tensile strength and strain at break simultaneously in the WG/DAS composites. The WG/DAS composites exhibit reduced moisture absorption in comparison with the WG/NEW composites. Formation of chemical bonding between DAS and WG is beneficial for the dispersion of DAS in the WG matrix and WG/DAS composites exhibit improved mechanical properties and reduced moisture absorption over the WG/NWS composites.  相似文献   
72.
Total mercury concentrations in organisms typical of those found in the Cilician Basin of the northeastern Mediterranean have been measured from 1977 to the present. These concentrations show seasonal variations. Shrimp shows an approximately constant concentration of mercury which might testify to the regulation capacity of shrimp for mercury. Crab, and particular fish, show a seasonal variation which may be correlated with the local application of mercury fungicide, rainfall, and the physiology of the organisms. The rapidity with which mercury applied to the land causes increased concentrations in fish is noteworthy.  相似文献   
73.
本文应用遥感技术,探讨了巴颜喀拉山北坡-青海省达日县段高寒草地资源及其退化高山草甸草地的成因、分布和判断标志,将研究区划分为5个草地类型和3个退化草地型,重点分析了高山草甸草地退化的主要原因和影象特征.  相似文献   
74.
The study aimed to estimate resource use efficiency and economic losses by using stochastic frontier analysis. The data set were collected in An Giang Province of Vietnam through personal interviews with 199 rice farmers. The results revealed that returns to scale are decreasing. Rice farmers had high levels of output-oriented and input-oriented technical efficiency with the means of 91.92 and 85.39 %, respectively. The mean environmental efficiency was 82.03 %. The mean efficiency of normal inputs was 61.20 %. Among the bad inputs, pesticide and energy were the least efficient ones with the mean values of 51.39 and 45.53 %, respectively, indicating serious overuses of these inputs. As regards normal inputs, capital had the lowest efficiency score at 21.08 %, followed by seed quantity at 26.4 %. Further, the total economic losses were estimated at 8261 thousand VND (380 USD) per hectare, which is equal to the sales of about 1600 kg of rice per hectare or the efforts to increase by 20 % of output level. This study suggests that rice farmers need to contract inputs, particularly environmentally detrimental inputs to improve profits. To improve the productive efficiency, the use of ecological engineering, collective pump and cultivation of three rice crops per year are possible options.  相似文献   
75.
Abstract

Two pyrethroid insecticides were compared with two fungicides for their effects on the rhizobial and seedling components of the N2‐fixing symbiosis in soybeans (Glycine max Merr. variety Olinda). In vitro growth of Rhizobium japonicum RI16, was inhibited in the order of HgCl2 > thiram > cypermethrin > permethrin. The emergence of the seedlings was stimulated by all chemicals tested. Also, none of the pesticides studied had any significant effect on N2 fixation (acetylene reduction), at the dosages used. Consequently, yields of the various organs were also not significantly influenced by the chemicals.  相似文献   
76.
Titanium dioxide (TiO2) is a promising sorbent for As removal. There are two main and physico-chemically distinct polymorphs of TiO2 in nature, namely anatase and rutile. Since the difference of arsenic removal by the two polymorphs of TiO2 is now well known, study on the arsenic removal efficiency and the underlying mechanism is of great significance in developing new remediation strategies for As-polluted waters. Here batch experiments were carried out in combination with instrumental analysis of X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) to investigate the effects, influential factors and mechanisms of As removal from aqueous solution by two types of nano TiO2 crystals. The adsorption behavior of anatase and rutile for As(V) and As(III) are well described by Freundlich equations. Anatase had higher As removal efficiency and adsorption capacity than rutile. Solution pH had no influence on the As adsorption of anatase TiO2, whereas the As removal by rutile TiO2 was increased by 7?C18% with pH from 4 to 10. Presence of accompanying anions such as phosphate, silicate, nitrate and sulfate, decreased the As(V) and As(III) removal by both crystals, with phosphate being the most effective. However, removal of As by rutile TiO2 was greatly enhanced in the presence of divalent cations i.e. Ca2+ and Mg2+. Shading of light decreased the removal of As(V) and As(III) of anatase by 15.5% and 17.5%, respectively, while a slight increase of As removal was observed in the case of Rutile TiO2. FT-IR characterization of As(V) or As(III)-treated nano TiO2 crystals indicated that both Ti-O and As-O groups participated in As adsorption. Both FT-IR and XPS analysis demonstrated that As(III) was photooxidated into As(V) when adsorbed by anatase under the light condition. Thus, the effect of crystal types and light condition on As removal should be taken into consideration when nano TiO2 is applied for As removal from water.  相似文献   
77.
Heavy metal concentrations in muscle and their relation to thegrowth of two marine fish species,including tonguefish( Cynoglossus arel) and mullet( Mugil cephalus),were studied. The samples were collected in Bach Dang estuary andconcentrations of heavy metals( As,Cd,Co,Mn,Cu,Zn,Pb,and V) in muscle of the fisheswere determined. The result showed that the accumulated trend of heavy metal is different between fish species. The concentration of As,Zn,Mn,V,Cu,Pb,Co and Cd in tonguefish were 73. 7 ± 30. 6,22. 82 ± 4.87,3. 44 ± 2. 13,1. 61 ± 0. 15,0. 71 ± 0. 13,0. 45 ± 0. 24,0. 03 ± 0. 02 and 0. 02 ± 0. 02 mg·g-1,respectively. Meanwhile the concentration of Zn,As,V,Mn,Cu,Pb,Co and Cd in mullet were 83. 41 ±19. 68,9. 78 ± 1. 92,1. 36 ± 0. 54,1. 29 ± 0. 51,0. 65 ± 0. 12,0. 42 ± 0. 20,0. 06 ± 0. 03 and0. 03 ± 0. 01mg·g-1,respectively. Comparison of metal levels among thesespecies indicated that the concentrations of As and Mn in tonguefish were significantly higher than those in mullet,whereas Zn levels in mullet were found to be higher than that in tonguefish. There is no significant differences of Cd,Co,Cu,Pb and V levels in muscle between two species. Significant inversed relationshipsbetween concentration levels of metals and lengths of tonguefish were found for Mn,Cu and Zn,butnot for As,Cd,Pb,and V. There were no significant relationships between the heavy metal concentrations and the length of mullet. In general,decreasesof the heavy metal concentrations corresponded to the increases of fish body lengths,particularly for As,Co,Cu,Mn and V and the exception for Cd. Terefore reduced risks were associated with consuming biggermullet fish,and increased risks of As and Cd were associated with consuming bigger tonguefish in Bach Dang river mouth.  相似文献   
78.
79.
和谐:可持续发展观的灵魂   总被引:9,自引:0,他引:9  
本文通过经济基础和上层建筑的关系说明进行环境文化建设的重要性,辨析了不同的环境价值观念和伦理道德,提出人与环境相融和谐的意识是可持续发展观的灵魂  相似文献   
80.
用于风险评估的二维爆炸场的数值模拟   总被引:3,自引:0,他引:3  
采用多流体Uuler型方法,对爆轰产物采用可变指数的多方气体状态方程,给出了对二维爆炸场进行模拟的方法,该法可为用压力一冲量准则对可能发生的爆炸事故进行风险评估提供基础。数值计算结果表明,该法适合于各种不同的几何外型,与现有实验结果符合较好。  相似文献   
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