中国南海表层叶绿素a季节内变化特征及成因

对中国南海表层叶绿素a季节内变化的研究有助于深入认识其海洋特征,满足渔情预报等实际应用需求。利用卫星观测资料分析南海表层叶绿素a不同季节的季节内变化特征,结果表明南海表层叶绿素a季节内振荡强度冬季最高。冬季和春季的季节内振荡最强区域都位于吕宋岛西北侧海区,夏季和秋季振荡较强的区域偏向菲律宾群岛一侧。分析表明研究海区表层温度和表层叶绿素a 存在负相关,冬强夏弱,北强南弱。大部分海区海面高度和叶绿素a 相关性不显著,但南海东南边缘海区海面高度和叶绿素a在季节内存在正相关。冬季海盆尺度逆时针旋转的环流结构应是这些现象产生的原因。除南海东南边缘海区、海南岛东南海区和吕宋岛西侧海区之外,风应力大小和热通量均与叶绿素a 在季节内呈正相关。这显示非局地风场和海流等因素、海洋动力调整过程可能在吕宋海峡以西和南海东南边缘的表层叶绿素a 季节内变化中起到重要作用。     

中国租赁住房发展的区域差异与影响因素

加快培育和发展住房租赁市场,是新时代中国住房制度改革的重要内容。基于2000年和2010年全国分县人口普查数据,运用GIS空间统计方法和空间计量模型,实证分析了中国337个地级以上城市的租赁住房发展区域差异与影响因素。研究表明：2000—2010年,中国租赁住房发展经历了“空间分散化”向“空间集聚”的发展态势,租赁住房发展高值区向长三角和珠三角城市群、西部地区的部分区域中心城市以及北京、厦门等经济发达城市更加靠拢;中国租赁住房发展和变化存在显著的空间集聚特征,且空间集聚趋势越来越强,而不同时期的中国租赁住房发展热点区分布有所变迁;空间计量模型表明,二三产业从业人员比例、住宅价格、租售比、外来人口比例、常住人口、65岁以上人口比例、家庭户规模和平均受教育年限等因素是影响2010年中国租赁住房发展区域差异的显著因素;而2000—2010年中国租赁住房发展变化主要与常住人口、外来人口比例、人均住房面积、65岁以上人口比例、平均受教育年限和少数民族比例等因素有关。     

盐湖氯化镁制备炼钢用镁钙造渣剂的实验研究

本文探讨了盐湖副产氯化镁应用于炼钢冶金造渣的可行性。以盐湖水氯镁石和石灰为原料,通过化学合成制备了氧化镁,再将氧化镁与石灰、粘结剂混配成型制备炼钢用镁钙造渣剂,考察了粘结剂硼酸的不同用量时造渣剂形成的球团强度和抗压强度及微观结构变化;同时研究了不同煅烧温度、煅烧时间、氧化镁掺杂量的情况下,造渣剂的活性及杂质脱除率。实验结果表明,利用该方法制备的镁钙造渣剂应用于钢铁冶金造渣过程,可有效地脱除碳、磷、硫、硅等杂质成分,提高转炉冶炼的冶金效果的同时实现了盐湖资源再利用,具有较好的推广应用前景。     

水溶性富勒烯对U(VI)在氧化多壁碳纳米管上吸附的影响

采用静态试验法研究了水溶性富勒烯对U(VI)在氧化多壁碳纳米管上吸附的影响。结果表明,羟基化富勒烯(C₆₀(OH)n)和羧基化富勒烯(C₆₀(C(COOH)₂)n)的加入对U(VI)在氧化多壁碳纳米管上的吸附量影响作用类似。在pH<3范围内,羟基化富勒烯和羧基化富勒烯对吸附几乎没有影响,在pH>3以后,二者开始抑制碳纳米管对U(VI)的吸附。较低浓度(10 mg/L)的C₆₀(OH)n对U(VI)的吸附几乎没有影响。而等量的C₆₀(C(COOH)₂)n已呈现出明显的抑制作用。但两者的作用机理不同,前者可能是由于羟基化富勒烯和U(VI)竞争氧化多壁碳纳米管上的吸附位点造成的,后者则可能改变了氧化多壁碳纳米管的表面电荷。用双位点模型对不同固液比和U(VI)初始浓度下U(VI)的吸附率随C₆₀(OH)n和C₆₀(C(COOH)₂)n初始浓度的变化进行了拟合得到了很好的结果。     

强降水对厦门地震台伸缩仪的影响

对厦门地震台伸缩仪趋势变化中出现的一些异常现象的研究表明,其异常并不是前兆异常,而是强降水的影响。     

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GPS网与旧网的坐标拟合

随着GPs技术的不断普及,许多城市都在利用它对城市控制网进行改建、扩建.而旧网的坐标资料以及多年积累的成果资料还须利用,这就涉及到新旧坐标的换算问题.本文以吴江市城镇地籍测量为例.     

Isolation and characterization of pathogenic <Emphasis Type="Italic">Listonella anguillarum</Emphasis> of diseased half-smooth tongue sole (<Emphasis Type="Italic">Cynoglossus semilaevis</Emphasis> Günther)

Studies were conducted to determine the cause of the acute mortality of half-smooth tongue sole Cynoglossus semilaevis Günther juveniles in a fish farm in Jimo, Shandong Province, China, in June 2006. Gross signs of the diseased tongue sole included several petechiae and ecchymoses on the body and fin necrosis and hemorrhagic lesion at the base of the fin. Bacteria were isolated from kidney, liver and hemorrhagic lesions of the diseased tongue sole. Among14 strains, SJ060621 was proved to be highly virulent to juvenile tongue sole with LD₅₀ value of <1.0×10⁵ colony forming units (CFU) mL⁻¹, while the remaining 13 were avirulent. Among the 16 antibiotics tested, SJ060621 was sensitive to gentamicin and nitrofurantoin. It was identified as Listonella anguillarum with conventional plate and tube tests in combination with API 20E analysis. 16S rRNA gene and partial HSP60 gene sequenceing analysis revealed that the strain was highly homologous with L. anguillarum. Examination of the infected musculature by electron microscopy indicated numerous bacteria and lots of macrophages containing phagocytosed bacteria. Histopathological investigations revealed severe necrotic degenerative changes in the infected organs. Indirect immunofluorescence assay (IFA) was employed to detect the location of occurrence of bacteria, and bacteria were found in aggregations in the inflammatory areas in musculature.     

Development and Characterization of Microsatellite Markers for the Pacific Abalone （Haliotis discus） via EST Database Mining

The EST database of the Pacific abalone (Haliotis discus) was mined for developing mierosatellite markers. A total of 1476 EST sequences were registered in GenBank when data mining was performed. Fifty sequences (approximately 3.4%) were found to contain one or more mierosatellites. Based on the length and GC content of the flanking regions, duster analysis and BLASTN, 13 microsatellite-containing ESTs were selected for PCR primer design. The results showed that 10 out of 13 primer pairs could amplify seorable PCR products and showed polymorphism. The number of alleles ranged from 2 to 13 and the values of Hoand He varied from 0.1222 to 0.8611 and 0.2449 to 0.9311, respectively. No significant linkage disequilibrium (LD) between any pairs of these loci was found, and 6 of 10 loci conformed to the Hardy-Weinberg equilibrium (HWE). These EST-SSRs are therefore potential tools for studies of intraspecies variation and hybrid identification.     

Groundwater response to dual tidal fluctuations in a peninsula or an elongated island

Groundwater flow in a peninsula or an elongated island is influenced by tidal fluctuations on both sides of the peninsula or island, which is named as dual tidal fluctuations. In this study, semianalytical solutions of transient groundwater flow in response to dual tidal fluctuations in an aquifer–aquitard system were presented for cases with and without the aquitard storage. These solutions were first derived using the Laplace transform and subsequently computed by the Fourier series numerical inverse Laplace transform. The derived solutions were found to agree very well with the results of numerical simulations by MODFLOW. The solution ignoring the aquitard storage approached the quasi‐steady state solution quickly when the mean sea level initial condition was used. The solutions with and without the aquitard storage were nearly the same at the early time and were separated from each other during the intermediate time, and the difference of solutions became constant at late time for small aquifer/aquitard storativity ratio and large tidal frequency. The propagation bias, which is the departure from the theoretical ratio of tidal attenuation to tidal lag, was enhanced not only with increase of the dimensionless specific leakage (aquitard/aquifer hydraulic conductance ratio) but also with decrease of the aquifer/aquitard storativity ratio and with the increase of the dimensionless tidal frequency. The solution with the aquitard storage was more sensitive to these three parameters. The newly developed solutions were capable of handling realistic initial conditions that might be approximated by piecewise linear functions. Copyright © 2012 John Wiley & Sons, Ltd.