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排序方式: 共有1070条查询结果,搜索用时 312 毫秒
971.
972.
Mrs Janet Vaughan Zehra Ali Sarah Bower Phillip Bennett Tim Chard Gudrun Moore 《黑龙江环境通报》1994,14(8):751-756
Two severely growth-retarded fetuses found to have maternal uniparental disomy (UPD) for chromosome 16 and trisomy 16 placental mosaicism both had an unfavourable outcome. Antenatally, the first case was complicated by an unexplained raised maternal serum alpha-fetoprotein concentration, preterm premature rupture of the membranes, and growth retardation detectable at 21 weeks' gestation, whilst the other had an unexplained raised maternal serum human chorionic gonadotrophin level, a two-vessel cord on ultrasound, and cessation of growth at 25 weeks. At post-mortem, both babies had an imperforate anus. Fetal maternal UPD may explain the poor outcome that occurs in some cases of confined placental mosaicism for chromosome 16 and is also associated with specific fetal abnormalities. 相似文献
973.
煤中痕量元素分布的多变量分析及实验研究 总被引:10,自引:1,他引:10
本文用多变量分析法研究了煤中痕量元素的分布,并用实验研究了有机溶剂提取前后青山烟煤中痕量元素的变化。多变量分析结果表明:As,Cr,Co,Ni,Cu,Cd,V,Pb等元素与Be,Ge在煤中具有不同的分布特征,对青山烟煤的实验研究结果则表明:Cr,Co,Ni,Cu,Cd,Pb等元素趋向于与煤中的矿物质相结合,而Be,Ge两元素有较强的有机亲和性。实验研究结果与多变量分析结果相符。 相似文献
974.
975.
976.
Babar Shahbaz Tanvir Ali Abid Qaiyum Suleri 《Mitigation and Adaptation Strategies for Global Change》2007,12(4):441-453
Pakistan has very low forest cover, but these forests are very diverse in nature and of significant importance for the livelihood
security of millions of rural people who live in and around these forests. Policies, institutions and processes form the context
within which individuals and households construct and adapt livelihood strategies, on the other hand these institutionally
shaped livelihood strategies may have an impact on the sustainability of natural resource use. The present paper aims to critically
analyse the forest policies of Pakistan. Implications for sustainable forest management and livelihood security of forest
dependent people are also given. The first forest policy of Pakistan was announced in 1955 followed by the forest policies
of 1962, 1975, 1980, 1988 as part of the National Agricultural Policy, 1991, and the latest in 2001. Most of the forest policies
were associated with the change of government. There was much rhetoric in some recent policies regarding the concept of “participation”
and “sustainable livelihoods” but in practice these policies are also replica of the previously top-down, autocratic and non-participatory
forest policies. Pakistan needs to develop a sustainable, workable, research-based, and people-friendly forest policy enable
to catering to the changing needs of stakeholders including government. 相似文献
977.
Mohammad Ali Tavanaie Ahmad Mousavi Shoushtari Fatemeh Goharpey 《Journal of Cleaner Production》2010,18(18):1866-1871
Carrier agent as one of the synthetic persistent molecules present in textile effluents considered as one of the most highly toxic, carcinogenic and serious inhibitor of the microbial respirometric activity. This chemical is used as accelerants in the dyeing or printing the hydrophobic fibers by dispersed dyes. Hydrophobic polypropylene (PP) fibers cannot be dyed by conventional dyeing process due to the absence of dye sites in the molecular chain and their high crystallinity. This study presents a carrier-free exhaust dyeing as an environmentally friendlier and cleaner process. In order to produce dyeable PP fibers, the PP was blended and melt spun with poly(butylene terephthalate) (PBT) at various ratios. First PP and PBT granules at blend ratios of 5, 10, 20, 30, 40 percent of PBT dispersed phase were physically mixed then the melt spinning of blended samples was carried out by a Maddock mixing zone extruder. The results showed that suitable exhaust dyeing process without using any carrier agents was possible for all PP/PBT alloy fiber samples. The dye uptake of samples significantly increased by increasing the PBT dispersed phase content. By increasing the PBT dispersed phase content decrease in the crystallinity percent resulting in significant enhancement in dye uptake of the alloy fiber samples was observed. A degree of four polynomial equation for dye uptake against blend ratio was obtained by which the optimum blend ratio was 72/28 percent of PP/PBT alloy fiber composition. In all alloy fiber dyed samples uniform coloration was observed. No considerable changes in the mechanical properties for dyed samples against undyed samples were observed. Interestingly, the best mechanical property among alloy fiber samples was observed in the sample containing 30 percent PBT dispersed phase which approximately corresponds to optimum blend ratio gained from mathematical calculations. In all PP/PBT alloy fiber samples strong fastness to soaping and very good to excellent fastness to light were achieved. 相似文献
978.
979.
980.
Tabassum Mumtaz Noor Amalina Yahaya Suraini Abd-Aziz Nor’Aini Abdul Rahman Phang Lai Yee Yoshihito Shirai Mohd Ali Hassan 《Journal of Cleaner Production》2010,18(14):1393-1402
Palm oil industries have been contributing significantly towards the country’s economy and increase standard of living among Malaysians. However, it has also been identified as the major contributor for discharging the largest pollution load throughout the country. Owing to high biochemical oxygen demand (BOD) and chemical oxygen demand (COD), the palm oil mill effluent (POME) cannot be discharged directly into the environment. Thus, palm oil industries are facing tremendous challenges in order to comply with environmental regulations. While anaerobic digestion has been employed by most mills as primary treatment, POME can also be a potential source of degradable organic material which can be converted into value-added products and fine chemicals. Organic acids generated during acid-phase anaerobic digestion of POME could be a potential carbon source for the production of polyhydroxyalkanoates (PHA)- a biodegradable thermoplastic material of microbial origin. This paper aims at understanding how organic acids from POME may serve as a renewable feedstock for the biosynthesis of PHA. 相似文献