顶空气相色谱法在我国水体分析中的应用

顶空气相色谱法(HS—GC),是测定固体和液体样品中痕量低沸点化合物的重要分析方法,在近年来有着快速的发展,该方法采用气体直接进样,干扰小,在食品,医疗,环境,生物等越来越多的领域有着广阔的应用前景.本文综述了近十年来我国顶空气相色谱法在水体分析检测中的应用,包括了在检测苯系物,卤代烃,含硫挥发物等诸多方面的应用.

面向水体污染生态修复的园林景观植物布局策略研究

以桂林某村落为例,研究面向水体污染生态修复的园林景观植物布局策略。检测污染程度以及污染分布的空间特征。配置合适的园林景观植物,在总面积、生态服务价值、景观植物适应度约束条件下,通过粒子群算法求解布局模型的最优解。结果表明:5个检测点水体污染生态修复系数达到了优秀等级;10个检测点水体污染生态修复系数达到了良好等级;3个检测点水体污染生态修复系数达到了合格等级;区域整体污染修复系数在0.8~1.0之间,修复效果达到良好等级;没有检测点处于合格以下(不合格),证明了布局方案的合理性。

萩芦溪流域水体纳污能力分析

该文根据萩芦溪流域水资源开发利用规划和经济社会发展规划,结合其水质功能类别和水质目标,通过污染源调查,针对影响水体水质的主要污染物TP、TN,采用水质模型和污染源集中概化理论计算出水体纳污能力,初步分析萩芦溪流域水质现状,提出水域的限制排污总量意见。

离子色谱法测定西湖水体中的Cl^-和NO_2^-

采用离子色谱法进行水质分析时,Cl-与NO2-的分离一直是个难题,特别是水体中Cl-浓度较大,而NO2-的浓度较小时,Cl-的色谱峰会完全覆盖NO2-的色谱峰.虽然可以分别采用色谱法测定Cl-、分光光度法测定NO2-,但步骤繁琐且测定的精确度不高.笔者用改进的离子色谱法分离测定西湖水体中的Cl-与NO2-,取得满意效果.

离子色谱法测定小清河及其支流水体中硝酸盐氮方法研究

１前言硝酸盐广泛存在于人类赖以生存的环境中，是自然界中最普遍的含氮化合物，也是环境污染的一项重要指标，因此，它是环境监测中的一个常规项目。测定水体中硝酸盐氮的方法很多，常用的有酚二磺酸分光光度法、镉柱还原法、戴氏合金还原法、离子色谱法、紫外分光光度法...

人工湖湖底形态优化数值模拟分析

为了合理确定人工景观湖湖底形态,采用丹麦水利研究所开发的Mike Flood一维二维耦合模型,以及Mike 3三维水动力模型对湖底形态进行研究,得到不同湖底形态对于水流动力的影响。结果显示,弧形深槽的湖底形态下湖区流场更加均匀,低流速的水流区域范围更小。

自2井水侵动态研究

产水气井水侵动态的研究是有水气藏生产管理中最为基础的工作。自2井是缝洞型有水气藏的典型代表,详细研究其水侵动态和产水规律具有重要的工程和理论意义。在核实储量的基础上,详细地研究了自2井的水体能量,应用非线性自动拟合法、视地质储量法等多种气藏工程方法对自2井的水侵动态进行了研究,并分析了地下溶洞对气井生产的影响,指出了井底溶洞的储水作用是保持该井后期长期稳产的根本原因之一。

Finite element analysis of the Taizhou Water Station Site

The Taizhou Water Station Site is an ancient masonry structure ruin built in the Southern Song Dynasty. The main structure was severely damaged. In order to understand its current structural properties and provide a scientific basis for protection design nonlinear finite element analysis and parameter analysis are carried out.The crack patterns deformations and stresses of the main structure under four load cases are analyzed by nonlinear finite element analysis and the effect of the backfill bulk density and modulus on the maximum principal tensile stress and maximum compressive stress are studied by parameter analysis.The results show that the most unfavorable condition for the foundation is the combination of weight＋backfill soil pressure＋additional load the most unfavorable load case to the main structure is weight ＋backfill soil pressure ＋water pressure＋additional heap load the maximum principal tensile stress of the main structure is very sensitive to the changes in the bulk density of the backfill soil.

Genetic Analysis of a Biomass Mutant in Oryza sativa

[ Objective ] The study aimed to reveal the genetic model of a biomass mutant in Oryza sativa. [ Method ] In the process of screening and identification of Bar-transgenic rice, a biomass mutant was found in 10 lines of T1 progenies. The mutant was investigated for genetic analysis and agronomic traits by herbicide spraying and PCR amplification. [ Result] The segregation ratio is consistent with mendelian law（3：1）. The mutant assumed not only higher plant height, wider straw and earlier florescence, but also more tillers, bigger spikes and resultantly higher biomass. PCR detections indicated that no co-segregation was observed between mutant traits and target gene（Bar） in the T-DNA inserted, proving that the mutant is not caused by the insertion of T-DNA containing target gene （Bar）. [ Conclusion] Our study may avail to understand the cloning of mutant gene and the mechanism of the mutant gene on biomass.

Fine Mapping of the Blast Resistance Gene P/75, Linked to Pii, on Rice Chromosome 9

The gene Pi15 for resistance of rice to Magnaporthe grisea was previously identified as being linked to the gene Pii. However, there is a debate on the chromosomal position of the Pii gene, because it was originally mapped on chromosome 6, but recent work showed it might be located on chromosome 9. To determine the chromosomal location of the Pi15 gene, a linkage analysis using molecular markers was performed in a F2 mapping population consisting of 15 resistant and 141 susceptible plants through bulked-segregant analysis (BSA) in combination with recessive-class analysis (RCA). Out of 20 microsatellite markers mapped on chromosomes 6 and 9 tested, only one marker, RM316 on chromosome 9, was found to have a linkage with the Pi15 gene with a recombination frequency of (19.1 ±3.7)%. To confirm this finding, four sequence-tagged site (STS) markers mapped on chromosome 9 were tested. The results suggested that marker G103 was linked to the Pi15 gene with a recombination frequency of (5.7±2.1)%. To find marker(s) more closely linked to the Pi15 gene, random amplified polymorphic DNA (RAPD) analysis was performed. Out of 1 000 primers tested, three RAPD markers, BAPi15486, BAPi15782 and BAPil5844 were found to tightly flank the Pi15 gene with recombination frequencies of 0.35%, 0.35% and 1.1%, respectively. These three RAPD markers should be viewed as the starting points for marker-aided gene pyramiding and cloning. A new gene cluster of rice blast resistance on chromosome 9 was also discussed.

Characterization and in-vivo evaluation of potential probiotics of the bacterial flora within the water column of a healthy shrimp larviculture system

A thorough understanding of the normal bacterial flora associated with shrimp larviculture systems contributes to probiotic screening and disease control. The bacterial community of the water column over a commercial Litopenaeus vannamei larval rearing run was characterized with both culture-dependent and culture-independent methods. A total of 27 phylotypes at the species level were isolated and identified based on 16S rDNA sequence analysis. Denaturing gradient gel electrophoresis （DGGE） analysis of the V3-V5 region of 16S rRNA genes showed a dynamic bacterial community with major changes occurred from stages zoea to mysis during the rearing run. The sequences retrieved were affiliated to four phyla, Proteobacteria, Actinobacteria, Bacteroidetes, and Firmicutes, with the family Rhodobacteraceae being the most frequently recovered one. Subsequently, 13 representative strains conferred higher larval survival than the control when evaluated in the in-vivo experiments; in particular, three candidates, assigned to Phaeobacter sp., Arthrobacter sp., and Microbacteriurn sp., significantly improved larval survival （P〈0.05）. Therefore, the healthy shrimp larviculture system harbored a diverse and favorable bacterial flora, which contribute to larval development and are of great importance in exploiting novel probiotics.

Change of Annual Extreme Water Levels and Correlation with River Discharges in the Middle-lower Yangtze River: Characteristics and Possible Affecting Factors

As one of the fastest developing regions in China, the middle-lower Yangtze River （MLYR） is vulnerable to floods and droughts. With obtained time series of annual highest water level （HWL）, annual lowest water level （LWL） and the corresponding fiver discharges from three gauging stations in MLYR that covering the period 1987-2011, the current study evaluated the change character- istics of annual extreme water levels and the correlation with fiver discharges by using the methods of Vend test, Mann-Whitney-Pettitt （MWP） test and double mass analysis. Major result indicated a decreasing/increasing trend for annual HWL/LWL of all stations in MLYR during the study period. A change point in 1999 was identified for annual HWL at the Hankou and Datong stations. The year 2006 was found to be the critical year that the relationship between annual extreme water levels and fiver discharges changed in the MLYR. With contrast to annual LWL in MLYR, further investigation revealed that the change characteristics of annual HWL were highly consistent with regional precipitation in the Yangtze River Basin, while the linkage with Three Gorges Dam （TGD） operation is not strong. Our observation also pointed out that the effect of serious down cutting of the riverbed and the enlargement of the cross-section area during the initial period of TGD operation caused the downward trend of the relationship between annual LWL and river discharge. Whereas, the relatively raised river water level before the flood season due to TGD regulation since 2006 explained for the changing upward trend of the relationship between annual HWL and river discharge.

Fluid-structure coupled analysis of underwater cylindrical shells

Underwater cylindrical shell structures have been found a wide of application in many engineering fields, such as the element of marine, oil platforms, etc. The coupled vibration analysis is a hot issue for these underwater structures. The vibration characteristics of underwater structures are influenced not only by hydrodynamic pressure but also by hydrostatic pressure corresponding to different water depths. In this study, an acoustic finite element method was used to evaluate the underwater structures. Taken the hydrostatic pressure into account in terms of initial stress stiffness, an acoustical fluid-structure coupled analysis of underwater cylindrical shells has been made to study the effect of hydrodynamic pressures on natural frequency and sound radiation. By comparing with the frequencies obtained by the acoustic finite element method and by the added mass method based on the Bessel function, the validity of present analysis was checked. Finally, test samples of the sound radiation of stiffened cylindrical shells were acquired by a harmonic acoustic analysis. The results showed that hydrostatic pressure plays an important role in determining a large submerged body motion, and the characteristics of sound radiation change with water depth. Furthermore, the analysis methods and the results are of significant reference value for studies of other complicated submarine structures.

Strengthening reinforced concrete beams using prestressed glass fiber-reinforced polymer-Part II:Analytical study

Strengthening reinforced concrete (R. C.) beams using prestressed glass fiber-reinforced polymer (PGFRP) was studied experimentally as described in Part I of this paper (Huang et al., 2005). In that paper, R. C. beams, R. C. beams with GFRP (glass fiber-reinforced polymer) sheets, and R. C. beams with PGFRP sheets were tested in both under-strengthened and over-strengthened cases. The test results showed that the load-carrying capacities (ultimate loads) of the beams with GFRP sheets were greater than those of the beams without polymer sheets. The load-carrying capacities of beams with PGFRP sheets were greater than those of beams with GFRP sheets. The objective of this work is to develop an analytical method to compute all of these load-carrying capacities. This analytical method is independent of the experiments and based only on the traditional R. C. and P. C. (prestressed concrete) theory. The analytical results accorded with the test results. It is suggested that this analytical method be used for analyzing and designing R. C. beams strengthened using GFRP or PGFRP sheets.

Science Letters:Two ancient rounds of polyploidy in rice genome

An ancient genome duplication (PPP1) that predates divergence of the cereals has recently been recognized. We report here another potentially older large-scale duplication (PPP2) event that predates monocot-dicot divergence in the genome of rice (Oryza sativa L.), as inferred from the age distribution of pairs of duplicate genes based on recent genome data for rice. Our results suggest that paleopolyploidy was widespread and played an important role in the evolution of rice.

Application of sequence stratigraphy to Triassic terrestrial strata in Tahe area of Tarim Basin

Based on a synthetic geological study of drilling,well logging and seismic data,core observations and geochemical analysis,it is recognized that Triassic sedimentary facies in the Tahe area of Tarim Basin include braided river deposits filling erosional valleys,and sublacustrine fan,canyon and delta facies.Braided river deposits filling erosional valleys are dominated by coarse-grained lithic quartz sandstone with oblique bedding,and represent the most important sedimentation type of sandstone in the study area.Sublacustrine fan and canyon facies are mainly distributed in the Middle Oil Member.Most delta sediments are deposited in highstand system tract(HST),Because of frequent changes in base level,delta sediments are commonly eroded and rarely preserved.Sedimentary cycles are clearly reflected by lithology,sedimentary structures and well logging data,and are closely related to the changes in lacustrine level.In accordance with the basic principle of sequence subdivision,seven type-I boundaries can be recognized in Triassic strata and six type-I sequences are subdivided correspondingly.In general,lowstand system tract(LST) is well developed within stratigraphic sequences and forms the main body of reservoir sandstone in this area;highstand system tract(HST) and transgressive system tract(TST) are often eroded by upper sequences or missed,Although various factors have different influences on terrestrial sequence stratigraphy,the classical sequence stratigraphy theory proposed by VAIL can be applied to terrestrial strata.

Impact energy analysis of turbulent water sprays for continuous centrifugal concentration

A SLon full-scale continuous centrifugal concentrator was used to reconcentrate hematite from a high gradient magnetic separation concentrate to study the effect of impact angle, concentrate mass and drum rotation speed on the impact energy of turbulent water sprays for continuous centrifugal concentration, under conditions of feed volume flow rate around 9 m3/h, feed solid concentration of 25%-35% and reciprocating velocity of water sprays at 0.05 m/s. The results indicate that a minimal critical impact energy is required in the water sprays for achieving continuous concentration of the concentrator; an unfitted impact angle reduces the impact efficiency, and the highest impact efficiency of 0.6416 is found at the mpact angle of 60°; the increase in concentrate mass leads to an increase in impact energy, and the highest impact efficiency is maintained when the concentrate mass varies in the range of 0.44-0.59 kg/s; when the concentrate mass and the pressure of water sprays are kept at around 0.45 kg/s and in the range of 0.4-0.6 MPa respectively, the impact energy increases proportionally with the increase of drum rotation speed.

STUDY ON CARRIER PURIFICATION TECHNOLOGY FOR HYDRAULIC OIL

The surface feature of contaminative oil is analysed and the theory of carrier purification technology for hydraulic oil is put forward. Experiments have been done in laboratory. The main performance of the purified oil has got to a level of new oil.

Water bodies extraction from TM images

Aiming at the problems of high time-consuming, low accuracy and weak versatility of the existing methods of wa- ter extraction based on TM image, this paper combines principal component analysis （PCA） with the modified normalized difference water index （MNDWI） which was improved by XU Han-qiu to construct a false color composite image that could separate water from others easily. This method can realize the water extraction based on TM image by analyzing the spectral characteristics of water in this false color image and establishing a water extraction model. This paper also compares the effi- ciency of this method with MNDWI, （TM2 ＋ TM3） - （TM4 ＋ TM5） and new water index （NWI）, which were applied in the city and mountain of Taiyuan, respectively. The results show that the proposed method can extract water body from TM im- age more rapidly and efficiently and its accuracy is up to 94.03 %. In addition, this method does not require a manual selec- tion threshold, which meets the research reuuirement of high automaticm.

Stability analysis of slopes of expansive soils considering rainfall effect

Typical failure types of slopes of expansive soils are divided to two kinds： slip in surface layer and slip in shallow layer. Based on total strength law of expansive soils, the relationship between its water content and shear strength inculding cohesion and friction angle, was studied in detail. Acoording to change of water content and depth effect during rainfall, distribution of shear strength in slopes of expansive soils was analyzed. Finally, with a slope of expansive soils in Nanning city of Guangxi Autonomous Region of China as a case, safety factor and slip surface was studied.