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排序方式: 共有198条查询结果,搜索用时 46 毫秒
21.
为理清中国适应气候变化的发展变化历程,梳理了中国适应气候变化制度的建设过程,国家、部门及地方等不同层面适应气候变化政策的发展脉络,以及重点脆弱领域农业农村地区适应政策的发展现状;针对不同领域适应气候变化行动,从农业、水资源、陆地生态系统、海岸带、人体健康等不同角度总结了国内所开展的具体适应行动及其成效,并重点分析了农业农村地区适应行动;根据中国适应气候变化政策与行动的发展特征,提出了适应政策行动的未来发展建议。 相似文献
22.
Yun-long He Rui-dong Xu Shi-wei He Han-sen Chen Kuo Li Yun Zhu Qing-feng Shen 《矿物冶金与材料学报》2019,26(6):689-700
A new alkaline pressure oxidative leaching process(with NaNO3 as the oxidant and NaOH as the alkaline reagent)is proposed herein to remove arsenic,antimony,and lead from bismuth-rich and arsenic-rich lead anode slime for bismuth,gold,and silver enrichment.The effects of the temperature,liquid-to-solid ratio,leaching time,and reagent concentration on the leaching ratios of arsenic,antimony,and lead were investigated to identify the optimum leaching conditions.The experimental results under optimized conditions indicate that the average leaching ratios of arsenic,antimony and lead are 95.36%,79.98%,63.08%,respectively.X-ray diffraction analysis indicated that the leaching residue is composed of Bi,Bi2O3,Pb2Sb2O7,and trace amounts of NaSb(OH)6.Arsenic,antimony,and lead are thus separated from lead anode slime as Na3AsO4·10H2O and Pb2Sb2O7.Scanning electron microscopy and energy-dispersive spectrometry imaging revealed that the samples undergo appreciable changes in their surface morphology during leaching and that the majority of arsenic,lead,and antimony is removed.X-ray photoelectron spectroscopy was used to demonstrate the variation in the valence states of the arsenic,lead,and antimony.The Pb(IV)and Sb(V)content was found to increase substantially with the addition of NaNO3. 相似文献
23.
针对传统虹膜分类需手工设计滤波器提取虹膜特征, 提取特征单一, 且通常需大量手工调参, 泛化能力较差的问题, 提出一种面向残差网络下多元特征的虹膜分类算法. 一方面将虹膜图像与Gabor特征相结合, 另一方面在网络结构中使用多个尺度的卷积核, 使学习到的虹膜特征更丰富, 从而提高图像特征的表征能力. 实验结果表明, 在固定类别中, 使用Softmax分类器进行多分类, 该算法在JLU虹膜数据库中的分类准确率可稳定在98.90%以上, 不低于DeepIrisNet和Resnet等网络结构, 且该算法的网络结构参数更少, 学习速度更快. 相似文献
24.
COMPARISON OF MAX—MIN APPROACH AND NN METHOD FOR RELIABILITY OPTIMIZATION OF SERIES—PARALLEL SYSTEM 总被引:2,自引:0,他引:2
Two heuristics, the max-min approach and the Nakagawa and Nakashima method, are consideredfor the redundancy allocation problem with series-parallel structure. The max-min approach canformulate the problem as an integer linear programming problem instead of an integer nonlinearproblem. This paper presents a comparison between those methods from the standpoint of solutionquality and computational complexity. The experimental results show that the max-min approach issuperior to the Nakagawa and Nakashima method in terms of solution quality in small-scale problems,but analysis of computational complexity shows that the max-min approach is inferior to other greedyheuristics. 相似文献
25.
W N Kuo J L Williams T Floyd-Jones C F Duggans D L Boone S O Smith R F Copeland 《Experientia》1979,35(8):997-998
Decreased activities of both the inhibitory modulator of adenosine 3':5'-monophosphate (cAMP)-dependent protein kinase (A-PK) as well as the stimulatory modulator of guanosine 3':5'-monophosphate (cGMP)-dependent protein kinase (G-PK) from the mouse cerebellum were noted due to the administration of excessive doses of ethanol, caffeine, and phenobarbital for up to 28 days. The dose-dependent of the inhibition of A-PK or the stimulation of G-PK was observed as a function of the amount of protein kinase modulators in the cerebellum of mice receiving different doses of ethanol. 相似文献
26.
The melanocyte differentiation program predisposes to metastasis after neoplastic transformation 总被引:1,自引:0,他引:1
Gupta PB Kuperwasser C Brunet JP Ramaswamy S Kuo WL Gray JW Naber SP Weinberg RA 《Nature genetics》2005,37(10):1047-1054
The aggressive clinical behavior of melanoma suggests that the developmental origins of melanocytes in the neural crest might be relevant to their metastatic propensity. Here we show that primary human melanocytes, transformed using a specific set of introduced genes, form melanomas that frequently metastasize to multiple secondary sites, whereas human fibroblasts and epithelial cells transformed using an identical set of genes generate primary tumors that rarely do so. Notably, these melanomas have a metastasis spectrum similar to that observed in humans with melanoma. These observations indicate that part of the metastatic proclivity of melanoma is attributable to lineage-specific factors expressed in melanocytes and not in other cell types analyzed. Analysis of microarray data from human nevi shows that the expression pattern of Slug, a master regulator of neural crest cell specification and migration, correlates with those of other genes that are important for neural crest cell migrations during development. Moreover, Slug is required for the metastasis of the transformed melanoma cells. These findings indicate that melanocyte-specific factors present before neoplastic transformation can have a pivotal role in governing melanoma progression. 相似文献
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Summary Otobanon obtained fromn-hexane extract ofMyristica simarum A. DC. was elucidated as 1-oxo-otobain by the physical spectra and chemical degradation.Acknowledgment. The authors are indebted to Chemical Research Center for financial support under the project No. CRC-6203, which supported by the National Council on Science Development of China. 相似文献
30.
固态法酿造苦荞白酒工艺初探 总被引:1,自引:1,他引:0
以苦荞麦为原料,采用传统的固态发酵法酿造苦荞白酒,并对苦荞白酒的固态发酵工艺进行了优化研究.实验结果表明:苦荞麦粉100 g,稻壳添加量18%,加酒曲量10%,打量水用量35%,常温培菌糖化48 h,密封发酵20 d,酒醅的酒精含量可达到7.8%,通过蒸馏可得到酒精度为36%(v/v)的原酒50 mL. 相似文献