Middle holocene soil and migration of climatic zones in the Guanzhong plain of China

IEECAS SKLLQG

Cross-correlation of excitation functions for different fragments and different scattering angles in Al-27(F-19, x)y reactions

Excitation functions have been measured for different projectile-like fragments produced in Al-27(F-19,x)y reactions at incident energies from 110.25 to 118.75 MeV in 250 keV steps. Strong cross section fluctuations of the excitation functions are observed. The cross- correlation coefficients of the excitation functions for different atomic number Z and for different scattering angle theta(cm) have been deduced. These coefficients are much larger than the statistical theoretical calculated ones. This indicates that there are strong correlations between different exit channels in the dissipative heavy ion Collision of Al-27(F-19,x)y.

Separation of enantiomers by nanoliquid chromatography and capillary electrochromatography using a bonded cellulose trisphenylcarbamate stationary phase

A cellulose trisphenylcarbamate-bonded chiral stationary phase was applied to nano-liquid chromatography (nano-LC) and capillary electrochromatography (CEC) with nonaqueous and aqueous solutions as the mobile phases. Several chiral compounds were successfully resolved on the prepared phase by nano-LC. The applicability of nonaqueous CEC on a cellulose derivative stationary phase was investigated with the organic solvents methanol, hexane, 2-propanol, and tetrahydrofuran (THF) containing acetic acid, as well as triethylamine as the mobile phases. Enantiomers of warfarin and praziquantel were baseline-resolved with plate numbers of 82 300 and 38 800 plates/m, respectively, for the first eluting enantiomer. The influence of applied voltage, concentration of nonpolar solvent, apparent pH, and buffer concentration in the mobile phase on the electroosmotic flow (EOF) and the mobility of the enantiomers was evaluated. Enantioseparations of traps-stilbene oxide and praziquantel were also achieved in aqueous CEC with plate numbers of 111 100 and 107 400 plates/m, respectively, for the first eluting enantiomer. A comparison between nonaqueous CEC and aqueous CEC based on a cellulose trisphenylcarbamate stationary phase was discussed. Pressure-assisted CEC was examined for the chiral separation of praziquantel and faster analysis with high enantioselectivity was acquired with the proper pressurization of the inlet vial.

Early Embryonic Exposure to Polychlorinated Biphenyls Disrupts Heat-Shock Protein 70 Cognate Expression in Zebrafish

Polychlorinated biphenyls (PCBs) are persistent environmental contaminants that have documented neurological effects in children exposed in utero. To better define neuronally linked molecular targets during early development, zebrafish embryos were exposed to Aroclor 1254, a mixture of PCB congeners that are common environmental contaminants. Microarray analysis of the zebrafish genome revealed consistent significant changes in 38 genes. Of these genes, 55% (21) are neuronally related. One gene that showed a consistent 50% reduction in expression in PCB-treated embryos was heat-shock protein 70 cognate (Hsc70). The reduction in Hsc70 expression was confirmed by real-time polymerase chain reaction (PCR), revealing a consistent 30% reduction in expression in PCB-treated embryos. Early embryonic exposure to PCBs also induced structural changes in the ventro-rostral cluster as detected by immunocytochemistry. In addition, there was a significant reduction in dorso-rostral neurite outgrowth emanating from the RoL1 cell cluster following PCB exposure. The serotonergic neurons in the developing diencephalon showed a 34% reduction in fluorescence when labeled with a serotonin antibody following PCB exposure, corresponding to a reduction in serotonin concentration in the neurons. The total size of the labeled neurons was not significantly different between treated and control embryos, indicating that the development of the neurons was not affected, only the production of serotonin within the neurons. The structural and biochemical changes in the developing central nervous system following early embryonic exposure to Aroclor 1254 may lead to alterations in the function of the affected regions.

节水农业中化控技术的应用研究

抗旱节水化控技术是一种很有发展前景的农业节水技术。它具有操作简便、投入少、见效快、易推广的优点 ,因而是一般常规技术所无法替代的。本文介绍了几种主要的抗旱节水化控制剂 (保水剂、土壤蒸发抑制剂、植物抗蒸腾剂、土壤结构改良剂和植物生长调节剂 )的特性及应用效果 ,并指出了该技术研究中存在的一些问题 ,以期为化学节水技术广泛应用提供理论参考。

东太平洋海隆13°N和大西洋Logatchev热液区附近热液柱的研究

海底热液柱的研究为我们认识海底热液活动提供了一个放大镜，为测定控制各种热液种类最终散布的化学反应提供了天然实验室，是我们认识海底热液活动环境效应、寻找海底热液多金属硫化物资源、定位新的热液喷口区、表征和定量海底热液活动释放的有利工具。本文在海底对热液柱研究概况了解的基础上总结了海底热液柱的类型、运动特征、影响其扩展的因素及其地球化学特征；在对2003年11月DY105-12、14航次第六航段和2005年10月DY105-17A航次大西洋航段，在EPR12°39′N～12°54′N区域和MAR Logatchev热液区（MAR 14°45＇N）获得的CTD数据分析的基础上，讨论了在东太平洋海隆和大西洋Logatchev热液区出现的温度异常；在对EPR12°39′N～12°54′N区域内所采水样地球化学数据分析的基础上，探讨了EPR12°39′N～12°54′N上方海底热液柱的地球化学特征及其影响因素，发现该调查区内Mg亏损可能由热液流体和海水混合达到平衡后上浮的一种贫Mg液体引起，Ca亏损是一种或几种因素共同作用的结果，其中最主要的原因可能是富二氧化碳流体夹带周围海水上升过程中形成碳酸钙颗粒，从而引起Ca的减小，Cl、Br富集可能是热液活动引起相分离后后期卤水注入海水的结果。

亚历山大藻（非PSP产毒株）毒理的初步研究

本文以一株不产PSP毒素的相关亚历山大藻（AC-1）为对象，研究了该藻株对褶皱臂尾轮虫、卤虫、黑褐新糠虾急性毒性效应和对糠虾的慢性毒性影响，同时对AFT毒素成分进行了研究，研究结果如下： 通过相关亚历山大藻（AC-1）对褶皱臂尾轮虫、卤虫、黑褐新糠虾的急性毒性影响研究，发现随着相关亚历山大藻（AC-1）密度的升高，轮虫、卤虫、糠虾的存活率逐渐降低，其96hLC50分别为：1500cells/ml，90cells/ml，5000cells/ml。比较研究三种生物对相关亚历山大藻（AC-1）敏感性可以看出，三种生物对该藻的敏感性顺序为：卤虫>轮虫>糠虾。 相关亚历山大藻（AC-1）对黑褐新糠虾的生长及种群繁殖有显著影响，我们发现在密度为50cells/ml藻液中，糠虾的繁殖就受到了不利影响。实验进行到63d结束时，糠虾日最高产虾数、总产幼虾数、总产虾天数都明显减少，初次产虾时间推迟，繁殖中断增加。且该藻对黑褐新糠虾亲虾的存活、生长也有一定的影响，糠虾亲虾的存活率为对照的71%，而体长和体重分别为对照组的87.3%和97.8%，但差异尚不显著（P>0.05）。 研究相关亚历山大藻（AC-1）各组分的毒性（藻液、藻细胞重悬液、藻细胞培养过滤液、内容物），发现藻液和藻细胞重悬液对褶皱臂尾轮虫种群数量及轮虫、卤虫、糠虾的存活率均有显著影响，表明相关亚历山大藻活体藻细胞的毒性最强。过滤液和内容物也显著降低了轮虫和卤虫的存活率，其对糠虾也有影响，但不显著，表明AFT毒素可能来源于细胞内，能分泌到细胞培养液中。 研究相关亚历山大藻（AC-1）AFT毒素的热稳定性、酸碱稳定性、去蛋白组分毒性、分子量范围、极性、多糖组分鉴定，表明AFT毒素为极性较强的多糖类物质，对热和酸碱是稳定的，其分子量范围在5K~50K之间。 以上结果表明相关亚历山大藻（AC-1）虽然不产生PSP毒素，但能产生极性多糖类毒素，对甲壳类等浮游动物的种群数量和资源补充产生不利影响。本研究为以后进一步研究AFT毒素的作用机制和毒素的化学结构奠定了基础，为全面评价亚历山大藻赤潮的危害提供了科学依据。

One century record of contamination by polycyclic aromatic hydrocarbons and polychlorinated biphenyls in core sediments from the southern Yellow Sea

Sixteen polycyclic aromatic hydrocarbons (PAHs) and 28 polychlorinated biphenyls (PCBs) were measured at a 2-cm interval in a core sample from the middle of the southern Yellow Sea for elucidating their historical variations in inflow and sources. The chronology was obtained using the Pb-210 method. PAHs concentrations decreased generally with depth and two climax values occurred in 14-16 cm and 20-22 cm layers, demonstrating that the production and usage of PAHs might reach peaks in the periods of 1956-1962 and 1938-1944. The booming economy and the navy battles of the Second World War might explain why the higher levels were detected in the two layers. The result of principal component analysis (PCA) revealed that PAHs were primarily owing to the combustion product. Down-cored variation of PCB concentrations was complex. Higher concentrations besides the two peaks being the same as PAHs were detected from 4 to 8 cm, depositing from 1980 to 1992, which probably resulted from the disposal of the out-dated PCB-containing equipment. The average Cl percentage of PCBs detected was similar to that of the mixture of Aroclor 1254 and 1242, suggesting they might origin from the dielectrical and heat-transfer fluid. The total organic carbon (TOC) content played a prevalent role in the adsorption of high molecular weight PAHs (>= 4-ring), while no obvious relationship among total PCBs, the concentration of congeners, and TOC was found.

Seasonal and interannual variation in water vapor and energy exchange over a typical steppe in Inner Mongolia, China

In this study, we conducted eddy covariance (EC) measurements of water vapor exchange over a typical steppe in a semi-arid area of the Inner Mongolia Plateau, China. Measurement sites were located within a 25-year-old enclosure with a relatively low leaf area index (similar to 1. 5 m(2) m(-2)) and dominated by Leymus chinensis. Energy balance closure was (H + LE) = 17.09 + 0.69 x (Rn - G) (W/m(2); r(2) = 0.95, n = 6596). Precipitation during the two growing seasons of the study period was similar to the long-term average. The peak evapotranspiration in 2004 was 4 mm d(-1), and 3.5 mm d(-1) in 2003. The maximum latent heat flux was higher than the sensible heat flux, and the sensible heat flux dominated the energy budget at midday during the entire growing season in 2003; latent heat flux was the main consumption component for net radiation during the 2004 growing season. During periods of frozen soil in 2003 and 2004, the sensible heat flux was the primary consumption component for net radiation. The soil heat flux component was similar in 2003 and 2004. The decoupling coefficient (between 0.5 and 0.1) indicates that evapotranspiration was strongly controlled by saturation water vapor pressure deficit (VPD) in this grassland. The results of this research suggest that energy exchange and evapotranspiration were controlled by the phenology of the vegetation and soil water content. In addition, the amount and frequency of rainfall significantly affect energy exchange and evapotranspiration upon the Inner Mongolia plateau. (c) 2007 Published by Elsevier B.V.

黄海海域前新生代残留盆地综合地质地球物理研究

China’s annual oil import volume has been increasing in recent years, but the oil price in the international market fluctuates and poses a severe threat to China’s economic development and national security. Therefore, it is of great importance to study the gas and oil exploration of Pre-Cenozoic Residual Basins in Yellow Sea. Yellow Sea has widespread and thick Mesozoic and Paleozoic strata that contain multilayer source rock. Hence, Yellow Sea Mesozoic and Paleozoic strata have good conditions of forming Pre-Cenozoic hydrocarbon reservoirs. Pre-Cenozoic Residual Basins are usually buried deep and then transformed many times in its long evolutional history. These characteristics make it difficult to apply a single method in exploring Pre-Cenozoic Residual Basins. On the other hand, it is highly effective to solve key problems of gas and oil exploration of Pre-Cenozoic Residual Basins in Yellow Sea by using integrated geological and geophysical methods which make full use of the advantages of various exploring techniques. Based on the principle of “the region controls the local; the deep restricts the shallow,” this study focuses on Pre-Cenozoic Residual Basins in Yellow Sea to describe the structure frame of its distribution, with gravity, magnetic, seismic, drill-hole and geological data and previous research findings. In addition, the distribution characteristics of Pre-Cenozoic Residual Basins in Yellow Sea are also analyzed. This paper explores the characteristics of error between gravity forward with constant density and gravity forward with variable density through the study on 2-D and 3-D gravity forward in frequency domain. The result shows that there is a linear relationship between error and depth of 2-D geological model but there is a nonlinear relationship between error and depth of 3-D geological model. The error can be removed according to its linear characteristics or statistical nature of nonlinear characteristics. There is also error between gravity inversion with constant density and gravity inversion with variable density due to variable density and edge-effect. Since there are not noticeable rules between the error and the two causes as variable density and edge-effect, this study adopts gravity inversion with variable density and methods to eliminate the edge-effect in basement inversion to improve inversion accuracy. Based on the study on the rock physical properties and strata distribution of Yellow Sea and adjacent regions, this study finds that there is a big density contrast between Cretaceous-Jurassic strata and their substratum. The magnetic basement of south Yellow Sea is regarded as top of Archeozoic-Proterozoic early strata, and there are double magnetic basements in north Yellow Sea. Gravity and magnetic data are used to inverse the gravity basement and magnetic basement of Yellow Sea, with seismic and drill-hole data as constrains. According to data of gravity and magnetic basement distribution, the depth of Cenozoic strata and previous research findings, this paper calculates the thickness of the Mesozoic and Pre-Mesozoic Residual Basins, draws the distribution outline of Pre-Cenozoic Residual Basins in Yellow Sea, and analyzes its macro-distribution characteristics. Gravity inversion is applied on a typical geological profile in Yellow Sea to analyze the characteristics of its fractures and magnetic basements. The characteristics of Pre-Cenozoic Residual Basins distribution outline in Yellow Sea and the fractures and magnetic basements of its typical profile shown by profile inversion provides new geophysical evidence for these structure views such as “the South Yellow Sea and the North Yellow Sea belong to different structural units” and “Sino-Korea and Yangtze blocks combine along Yellow Sea East Fractured Zone in Yellow Sea”.

Zoneamento climático da Heveicultura no Brasil.

Para o zoneamento da aptidão climática da heveicultura no Brasil, considerou-se as exigências climáticas da espécie a ser cultivada e da principal doença que afeta a cultura. Neste trabalho, utilizou-se a temperatura média anual do ar, a deficiência hídrica no solo e a temperatura média do mês mais frio, como condicionantes do desempenho da cultura e da ocorrência de surtos epidêmicos do Microcyclus ulei (P. Henn) V. Arx., principal patógeno da seringueira no Brasil e causador do "mal-das-folhas". Considerando esses fatores, elaborou-se uma carta de aptidão climática da heveicultura no Brasil, baseada em isolinhas de temperatura, precipitação, e de outros fatores de interesse, estabelecendo-se, assim, as regiões brasileiras com condições climáticas aptas, restritas, marginais e inaptas para o cultivo comercial da seringueira.

A Nondeterministic Minimization Algorithm

The problem of minimizing a multivariate function is recurrent in many disciplines as Physics, Mathematics, Engeneering and, of course, Computer Science. In this paper we describe a simple nondeterministic algorithm which is based on the idea of adaptive noise, and that proved to be particularly effective in the minimization of a class of multivariate, continuous valued, smooth functions, associated with some recent extension of regularization theory by Poggio and Girosi (1990). Results obtained by using this method and a more traditional gradient descent technique are also compared.