191 research outputs found

    Si-Cu合金化渣剂精炼去除冶金级硅中金属杂质

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    采用Si-Cu合金精炼与CaO-SiO2-CaCl2造渣精炼相结合的方法对冶金级硅进行精炼,通过多种分析方法考察了合金造渣过程、渣剂添加剂和合金成分对金属杂质铁(Fe)、铝(Al)和钙(Ca)去除效果的影响。结果表明,提高Si-Cu合金中的Cu含量可以有效增加Cu3Si相在Si中的含量,合金造渣过程会产生多而弥散的合金相,造渣后的金属杂质Fe、Ca聚集在Si-Cu合金的Cu3Si相中。在渣剂中添加CaCl2助溶剂可有效提高金属杂质Fe、Al和Ca的去除率。此外,随着Si-Cu合金中Cu含量的增加,Cu在合金中的析出现象明显,Fe的去除率上升,Al的去除率不变,Ca的去除率下降。当Si-30%Cu合金与45%CaO-45%SiO2-10%CaCl2渣剂进行精炼后,Fe的去除率为68%,Al的去除率为94%,Ca的去除率为86%

    A modified ecological footprint analysis to a sub-national area:the case study of Zhejiang Province

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    在全球公顷和国家公顷的模型基础上,建立了省公顷生态足迹模型。采用2005年浙江省平均土地单位产量核算了浙江省各地的生态足迹,并与全球公顷和国家公顷法的结果进行了比较分析。从省公顷模型的结果可以看出,浙江省生态足迹达1.18 S-nHM2/人(省公顷,记为:S-nHM2),而生物承载力只有0.24 S-nHM2/人,生态赤字达0.94 S-nHM2/人,生态压力指数达4.91,是典型的生态赤字地区。另外,浙江省各地生态足迹空间差异较大,与全省平均水平相比,舟山和温州处于高强度生态压力,宁波、杭州、台州、金华和绍兴处于中强度生态压力,而丽水、衢州、湖州和嘉兴处于低强度生态压力。最后借助IPAT的分析,发现杭州、金华、嘉兴、湖州和衢州等地的万元gdP占用足迹不同程度地高于全省平均水平,并指出在一定条件下,应结合当地的经济发展程度合理提升资源利用效率的技术水平。The ecological footprint model on the basis of sub-national hectare was presented in this paper according to the ecological footprint concept and model on the basis of global hectare or national hectare.The ecological footprint and its composition of each city in Zhejiang Province were evaluated and analyzed by using the modified model and the actual yield per unit area of Zhejiang in 2005.The results were compared with those which were evaluated in global hectare or national hectare method,and the differences were analyzed among them.When using sub-national hectare as the evaluation criterion,the ecological footprint,the ecological capacity and the ecological deficit of Zhejiang Province in 2005 would be 1.18s-nhm2/cap,0.24s-nhm2/cap and 0.94s-nhm2/cap respectively,and the ecological pressure index was 4.91.The results suggest that Zhejiang Province is a representative area that has a large ecological deficit and high ecological pressure.They also suggested that there was a significant spatial difference according to the ecological footprint and its composition among the cities of Zhejiang.Compared with the average level of city ecological footprint in Zhejiang Province,Lishui,Quzhou,Huzhou and Jiaxing were in low ecological pressure states,and Ningbo,Hangzhou,Taizhou,Jinhua and Shaoxing were in middle ecological pressure states,while Zhoushan and Wenzhou were in high ecological pressure states.In the end,by applying IPAT,more eco-footprint demand of 104yuan GDP was found in Hangzhou,Jinhua,Jiaxing,Huzhou and Quzhou,which have a higher level than the average of Zhejiang,and suggestions were proposed that the level of local economic development must be considered to promote resource use efficiency.国家自然科学基金资助项目(40471055

    海洋储碳机制及区域碳氮硫循环耦合对全球变化的响应

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    海洋作为地球表面最大的活跃碳库,其碳收支在很大程度上决定了全球气候变化的走向.然而,海洋碳循环是一个多时空尺度的过程,相关的碳收支估算存在很大的; 不确定性,其控制过程与机理更是一个颇具挑战性的难题(胡敦欣等, 2015),特别是海洋储碳机制,是研究全球变化及应对的核心内容之一.国家重点研发计划专项全球变化及应对项

    Cloning and expression analysis of lipopolysaccharide-induced TNF-α(LITAF) of Japanese scallop (Mizuhopecten yessoensis)

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    脂多糖诱导的肿瘤坏死因子(lIPOPOlySACCHArIdE-InduCEd Tnf-AlPHA fACTOr,lITAf)是一类重要的炎症细胞因子,在先天性免疫系统中发挥重要的介质作用。文章根据虾夷扇贝lITAf基因EST序列,应用rACE技术克隆了虾夷扇贝lITAf全长CdnA,对序列及编码的氨基酸进行生物信息学分析。结果显示,该基因CdnA全长1 551 bP,其5′非编码区包含76 bP,3′非编码区包含1 001 bP;开放阅读框(Orf)为474 bP,编码157个氨基酸,氨基酸序列中存在一个保守的lITAf结构域;理论分子量16.99 kdA,等电点为6.24。lITAf基因序列为3 698 bP,由3个外显子和两个内含子组成。利用实时荧光定量PCr技术分析lITAf在虾夷扇贝不同组织、不同胚胎发育阶段以及鳗弧菌(VIbrIO AnguIllAruM)刺激后各时间段的表达情况。结果表明:lITAf基因在所检测的6个成体组织中均有表达,其中肾脏的表达量最高;胚胎发育的7个时期中,担轮幼体时期表达量最高;菌刺激36 H实验组与对照组的表达量差异大。lITAf基因是lITAf家族的一员,推测lITAf基因参与虾夷扇贝的先天性免疫反应。The lipopolysaccharide-induced TNF-alpha factor(LITAF) is an inflammatory cytokine,which plays an important role in innate immunity system.Based on the expressed sequence tag(EST) of Japanese scallop(Mizuhopecten yessoensis),the cDNA of LITAF gene was amplified using rapid amplification of cDNA ends(RACE) approach.Results showed that the full-length cDNA of LITAF is 1 551 bp consisting of a 5′ untranslated region(UTR) of 76 bp,a 3' UTR of 1 001 bp,and an open reading frame(ORF) of 474 bp encoding a polypeptide of 157 amino acids,and there is a conserved LITAF domain in amino acid sequences.The estimated molecular mass is 16.99 kDa and the theoretical isoelectric point is 6.24.The total length of LITAF is 3 698 bp,which includes three exons and two introns.Real-time quantitative PCR was carried out to measure LITAF mRNA expression in adult tissues and monitor mRNA expression patterns during embryonic development after bacteria(Vibrio anguillarum) challenged.The expression level of LITAF mRNA was detected in all the adult tissues with the highest in the kidneys.The trochophore owns the highest expression level of LITAF in embryonic development.LITAF expression showed significant difference(P<0.01)between the control and bacteria challenged specimens at 36 h.These results suggest that the LITAF should be a member of the LITAF family that perhaps involved in the innate immune response of Japanese scallop.国家海洋公益性行业科研专项(编号:200805037);国家自然科学基金项目(编号:31140073)资

    Analysis of the nutrient distribution features and affecting factors in the Jiulongjiang estuary

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    根据2009、2010年“丰水期“和“枯水期“四航次九龙江河口混合区的调查资料,且结合历史资料对营养盐含量及分布特征、周日变化特征进行了统计和相关分析,研究了九龙江流域营养盐输入海洋的变化过程,探讨九龙江河口营养盐伴随潮汐变化,以及河口混合过程中的生物地球化学行为。调查期间溶解无机氮、硅和磷含量的平面分布呈现出由径流冲淡水高值向河口外海端递减的变化趋势;在涨潮时,河口区感潮段高溶解无机氮、硅、磷营养盐的陆源冲淡水与低溶解无机氮、硅、磷营养盐外海水相遇,随着外海水的侵入,外海水的作用逐渐加强,在稀释混合过程中呈现出无机营养盐逐步降低的变化趋势,退潮时则相反;营养盐在这复杂的河口过程中往往表现出在水动力的作用下稀释混合是主要过程,无机氮和活性硅酸盐在河口稀释混合过程中呈现保守性特征,活性磷酸盐在河口转移(补充)过程的行为复杂化,呈现缓冲作用为主。Based on the historical data and the data from four surveys in the wet season and dry season of 2009 and 2010 in the Jiulongjiang estuary,the concentration and distribution of nutrient were discussed in the mixing process.Furthermore,the daily variation of nutrient concentration with the tide was also discussed.The results showed that:(1) the concentration of total dissolved inorganic nitrogen,silicate and phosphate all decreased gradually from the river runoff to seawater;(2) in high tide,in the mixing process of the runoff with high nutrient concentration and the seawater with low concentration of nutrient,the concentration of nutrient decreased due to seawater.On the contrary,during the ebb,the concentration of nutrient increased due to the runoff;(3) in the mixing process in Jiulongjiang estuary,nitrogen and silicate were both conservatively diluted,but phosphate was buffered because of the complicated transfer and complement of phosphate.国家海洋局公益性项目(200805064);国家海洋局第三海洋研究所基本科研业务费项目(海三科2009021);海三科200900

    对立定跳远训练方法的研究

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    本文通过对大、中、小学5个年龄段男女近450名学生的13个运动项目成绩和立定跳远成绩进行测试,找出与立定跳远成绩相关性较大运动项目,从而制定较科学的训练方法,提高学生的立定跳远成绩

    红花组分HSYA对人胃腺癌BGC-823移植瘤裸鼠VEGF蛋白、KDR与缺氧诱导因子表达的影响

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    目的:研究红花组分羟基红花黄色素A(HSYA)对人胃腺癌皮下移植瘤裸鼠血管内皮生长因子(VEGF)蛋白、含激酶插入区受体(KDR)和缺氧诱导因子(HIF-1α)mRNA与蛋白表达的影响。方法:采用BALB/C nu/nu裸小鼠接种人胃腺癌细胞株BGC-823于右前肢腋部皮下建立裸鼠人癌移植瘤模型,随机分为模型组、对照组、HSYA高、低剂量组(0.056g/L、0.028g/L),观察抑瘤作用,酶联免疫吸附测定(ELISA)法检测瘤组织VEGF与HIF-1α蛋白以及血清VEGF蛋白表达;蛋白印迹(Western blotting)法测定瘤组织KDR磷酸化蛋白的表达;实时荧光定量PCR(RTFQ-PCR)法检测瘤组织KDR及HIF-1αmRNA表达。结果:HSYA低剂量组抑瘤明显,该组瘤组织及血清VEGF蛋白表达降低,瘤组织KDR磷酸化蛋白表达减弱,与模型组比较差异明显(P<0.05,P<0.01);HIF-1α蛋白表达较模型组瘤组织明显减少(P<0.01)。KDR mRNA表达与模型组相比减弱,差异有统计学意义(P<0.05)。结论:一定浓度的HSYA抑制肿瘤生长的可能机制与抑制VEGF、HIF-1α蛋白的表达,减弱KDR蛋白磷酸化及其基因表达,从而抑制内皮细胞活化阻碍肿瘤血管新生以及降低肿瘤缺氧微环境对血管生成的诱导有关

    Differential regulation of stiffness, topography, and dimension of substrates in rat mesenchymal stem cells

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    The physiological microenvironment of the stem cell niche, including the three factors of stiffness, topography, and dimension, is crucial to stem cell proliferation and differentiation. Although a growing body of evidence is present to elucidate the importance of these factors individually, the interaction of the biophysical parameters of the factors remains insufficiently characterized, particularly for stem cells. To address this issue fully, we applied a micro-fabricated polyacrylamide hydrogel substrate with two elasticities, two topographies, and three dimensions to systematically test proliferation, morphology and spreading, differentiation, and cytoskeletal re-organization of rat bone marrow mesenchymal stem cells (rBMSCs) on twelve cases. An isolated but not combinatory impact of the factors was found regarding the specific functions. Substrate stiffness or dimension is predominant in regulating cell proliferation by fostering cell growth on stiff, unevenly dimensioned substrate. Topography is a key factor for manipulating cell morphology and spreading via the formation of a large spherical shape in a pillar substrate but not in a grooved substrate. Although stiffness leads to osteogenic or neuronal differentiation of rBMSCs on a stiff or soft substrate, respectively, topography or dimension also plays a lesser role in directing cell differentiation. Neither an isolated effect nor a combinatory effect was found for actin or tubulin expression, whereas a seemingly combinatory effect of topography and dimension was found in manipulating vimentin expression. These results further the understandings of stem cell proliferation, morphology, and differentiation in a physiologically mimicking microenvironment

    中国物理海洋学研究70年:发展历程、学术成就概览

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    本文概略评述新中国成立70年来物理海洋学各分支研究领域的发展历程和若干学术成就。中国物理海洋学研究起步于海浪、潮汐、近海环流与水团,以及以风暴潮为主的海洋气象灾害的研究。随着国力的增强,研究领域不断拓展,涌现了大量具有广泛影响力的研究成果,其中包括:提出了被国际广泛采用的"普遍风浪谱"和"涌浪谱",发展了第三代海浪数值模式;提出了"准调和分析方法"和"潮汐潮流永久预报"等潮汐潮流的分析和预报方法;发现并命名了"棉兰老潜流",揭示了东海黑潮的多核结构及其多尺度变异机理等,系统描述了太平洋西边界流系;提出了印度尼西亚贯穿流的南海分支(或称南海贯穿流);不断完善了中国近海陆架环流系统,在南海环流、黑潮及其分支、台湾暖流、闽浙沿岸流、黄海冷水团环流、黄海暖流、渤海环流,以及陆架波方面均取得了深刻的认识;从大气桥和海洋桥两个方面对太平洋–印度洋–大西洋洋际相互作用进行了系统的总结;发展了浅海水团的研究方法,基本摸清了中国近海水团的分布和消长特征与机制,在大洋和极地水团分布及运动研究方面也做出了重要贡献;阐明了南海中尺度涡的宏观特征和生成机制,揭示了中尺度涡的三维结构,定量评估了其全球物质与能量输运能力;基本摸清了中国近海海洋锋的空间分布和季节变化特征,提出了地形、正压不稳定和斜压不稳定等锋面动力学机制;构建了"南海内波潜标观测网",实现了对内波生成–演变–消亡全过程机理的系统认识;发展了湍流的剪切不稳定理论,提出了海流"边缘不稳定"的概念,开发了海洋湍流模式,提出了湍流混合参数化的新方法等;在海洋内部混合机制和能量来源方面取得了新的认识,并阐述了混合对海洋深层环流、营养物质输运等过程的影响;研发了全球浪–潮–流耦合模式,推出一系列海洋与气候模式;发展了可同化主要海洋观测数据的海洋数据同化系统和用于ENSO预报的耦合同化系统;建立了达到国际水准的非地转(水槽/水池)和地转(旋转平台)物理模型实验平台;发展了ENSO预报的误差分析方法,建立了海洋和气候系统年代际变化的理论体系,揭示了中深层海洋对全球气候变化的响应;初步建成了中国近海海洋观测网;持续开展南北极调查研究;建立了台风、风暴潮、巨浪和海啸的业务化预报系统,为中国气象减灾提供保障;突破了国外的海洋技术封锁,研发了万米水深的深水水听器和海洋光学特性系列测量仪器;建立了溢油、危险化学品漂移扩散等预测模型,为伴随海洋资源开发所带来的风险事故的应急处理和预警预报提供科学支撑。文中引用的大量学术成果文献(每位第一作者优选不超过3篇)显示,经过70年的发展,中国物理海洋学研究培养了一支实力雄厚的科研队伍,这是最宝贵的成果。这支队伍必将成为中国物理海洋学研究攀登新高峰的主力军
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