光释光测年和孢粉分析揭示的晚冰期以来科尔沁沙地演化过程

利用光释光测年技术对科尔沁沙地的7个风成砂-砂质古土壤剖面进行年代测试,结合地层和孢粉分析得到晚冰期以来科尔沁沙地的演化过程如下:16~10 ka B.P.,风成砂出现,沙地活化;10~3 ka B.P.,砂质古土壤发育,沙地固定;约3 ka B.P.前后,风成砂出现,沙地活化;3 ka B.P.至今,多层弱发育砂质古土壤和风成砂的交替出现,指示晚全新世科尔沁沙地的多次固定与活化;从约4~2 ka B.P.,沙地环境由草甸草原逐渐退化为典型草原。分析表明,3 ka B.P.以前科尔沁沙地的演化完全受气候变化的控制,之后(尤其是辽代以后)人类活动的影响日益增强。     

合成铁氧化物矿物对苯酚的吸附实验研究

采用TEM、X射线衍射分析及BET比表面积测定等手段对合成的针铁矿、赤铁矿两种矿物进行表征,对此两种矿物对苯酚的吸附特性并批处理吸附实验研究结果表明,针铁矿对苯酚的吸附量大于赤铁矿的吸附量;针铁矿吸附苯酚的pH吸收边为峰型曲线,且峰值在pH 7～8。Langmuir方程拟合结果的吻合程度较之Henry线性方程与Freundlich方程高。实验中氧化铁矿物表面对苯酚的吸附则主要表现为表面分子吸附,可能存在表面疏水性作用,而静电离子交换和表面配合吸附模式不明显。     

东、黄海大气湿沉降中常量阴离子组分的研究

用离子色谱法分析了嵊泗群岛和千里岩岛两个观测站湿沉降样品中的F^-、NO3^-、Cl^-和SO4^2-等4种阴离子。结果表明，它们的月均浓度之间差别较大，季节性变化明显；与近岸城市相比，具有显的海洋性特征；对全年中酸雨的统计表明，两个观测站都受到了酸雨的影响，而嵊泗群岛更严重一些。     

大气CO2标准气浓度标定及采样瓶CO2浓度分析系统

对美国NOAA／CMDL开发的用于我国大气本底监测的非色散红外CO2瓶分析和标准气标定系统做了测试与讨论,并对在青海瓦里关、浙江临安、黑龙江龙凤山和北京上甸子所采集到的实验性空气样品中的CO2浓度进行了测量,与瓦里关在线连续测量结果进行了对比,结果均表明该系统具有较高的灵敏度、精确度和较好的稳定性,具备了从进样到数据处理等较为完整的自动化功能,具有简便易行、准确可靠等特点,可用于大气CO2标准气体的标定及采样瓶分析。测量和对比结果也表明,样瓶采样和分析系统可在一定程度上替代现场连续测量系统,在不同的地点进行采样并进行集中分析也是一种较为经济、实用的方法。     

WEIGHTED ANALYSIS OF PRINCIPAL COMPONENTS: TWO APPROXIMATIONS TO STATISTICAL WEIGHTS

Two approximate methods for weighted principal components analysis (WPCA) were devised and testedin numerical experiments using either empirical variances (obtained from replicated data) or assumedvariances (derived from unreplicated data). In the first ('spherical') approximation each data vector wasassigned a weight proportional to the geometrical mean of its variances in all dimensions. Thearithmetical mean of variances was used instead in the other approximation. Both the numericalexperiments with artificial data containing random errors of various kinds (constant, proportional,constant plus proportional, Poisson) and the analysis of two sets of Raman spectra clearly indicated thenecessity of introducing statistical weights. The spherical approximation was found to be slightly betterthan the arithmetical one. The application of statistical weighting was found to improve the performanceof PCA in estimation problems.     

IDENTIFICATION OF FINITE IMPULSE RESPONSE MODELS WITH CONTINUUM REGRESSION

The use of continuum regression(CR)for the identification of finite impulse response(FIR)dynamicmodels is investigated.CR encompasses the methods of principal component regression(PCR),partialleast squares(PLS)and multiple linear regression(MLR).PCR and MLR are at the two extremes of thecontinuum.In PCR and PLS,cross-validation is used to determine the optimum number of factors or‘latent variables’to retain in the regression model.CR allows one to vary the method in addition.Cross-validation then determines both the optimum method and the number of latent variables.The CR‘prediction error surface’—a function of the method and number of latent variables—is elucidated.Theoptimal model is defined as the minimum of this surface.Among the cases studied,the optimal modelusually comes from the region of the continuum between PCR and PLS.Few derive from the regionbetween PLS and MLR.It is also demonstrated that FIR models identified by CR have frequency domainproperties similar to those identified by PCR.     

Non-specific immune response of bullfrog Rana catesbeiana to intraperitoneal injection of bacterium Aeromonas hydrophila

Non-specific immune response of bullfrog Rana catesbeiana to pathogenic Aeromonas hydrophila was studied to 60 individuals in two groups.Each bullfrog in bacterium-injected group was injected intraperitoneally(i.p.) with 0.2 ml bacterial suspension at a density of 5.2 × 106 CFU/ml,while each one in control group injected i.p.with 0.2 ml sterile saline solution(0.85%,w/v).Three bullfrogs in both groups were sampled at 0,1,3,7,11,15 and 20 days post-injection(dpi) for the evaluation of non-specific immune parameters.It was observed that intraperitoneal injection of A.hydrophila significantly increased the number of leucocytes and that of NBT-positive cells in peripheral blood.Significant increases in serum bactericidal activity and serum acid phosphatase activity were also observed in the bacterium-injected frogs when compared with those in the control group.However,a significant reduction was detected in vitro in phagocytosis activity of peripheral blood phagocytes.No significant difference in changes in the number of peripheral erythrocytes,serum superoxide dismutase(SOD) activity,and lysozyme activity was detected between the two groups.It is suggested that bullfrogs may produce a series of non-specific immune reactions in response to the A.hydrophila infection.     

Investigation on influence factors of dual laterologs curve form

In order to investigate the influences of caliper, formation thickness and invaded zone on the form of dual laterologs, forward modeling technique were applied to calculate the dual laterologs for different cases. The result shows that the resistivity logs become smoother and lower as the borehole diameter increases, the increase of the contrast between mud resistivity and formation resistivity induce the logs to be more pointed. When the formation thickness is less than lm, the two-peak on the logs for resistive invasion vanished, and for thickness between 1 m and 4 m, the form of logs does not vary significantly. If the formation thickness is greater than 4 m, a platform appears on the logs at the middle of the formation. The thinner the invaded zone is, the more obvious the invasion feature on the laterologs is. For thick invaded zone the form of logs tend to be that of an uninvaded resistive formation. The form and amplitude of logs depend on the resistivity contrast between invaded zone, uninvaded formation and adjacentlayers.     

Pt/十六烷基三甲基溴化铵纳米聚集体修饰玻碳电极促进析氢(英文)

A novel, cost-effective, and simple electrocatalyst based on a Pt-modified glassy carbon electrode(GCE), using cetyltrimethylammonium bromide(CTAB) as a cationic surfactant, is reported. Amphiphilic CTAB molecules were adsorbed on GCE by immersion in a CTAB solution. The positively charged hydrophilic layer, which consisted of small aggregates of average size less than 100 nm,was used for accumulation and complexation of [PtCl2. anions by immersing the electrode in Ksolution. The modified electrode was characterized using scanning electron microscopy,energy-dispersive X-ray spectroscopy, impedance spectroscopy, and electrochemical methods. The electrocatalytic activity of the Pt particles in the hydrogen evolution reaction(HER) was investigated.The results show that the CTAB surfactant enhances the electrocatalytic activity of the Pt particles in the HER in acidic solution.     

SIMULTANEOUS ANALYSIS OF Co(Ⅱ),Ni(Ⅱ),Cu(Ⅱ),Zn(Ⅱ)AND Cd(Ⅱ)BY SPECTROPHOTOMETRY AND THE KALMAN FILTER

This paper describes the simultaneous determination of cobalt,nickel,copper,zinc and cadmium byspectrophotometry and the Kalman filter method.Co(Ⅱ),Ni(Ⅱ),Cu(Ⅱ),Zn(Ⅱ)and Cd(Ⅱ)react with 5-bromo-2-(2-pyridylazo)-5-diethylaminophenol(5-Br-PADAP)in the presence of cationic surfactant cetylpyridinium bromide(CPB)to form five different coloured ternary complexes.The absorption curves ofthese complexes overlap severely in the scanning range 500-620 nm.The Kalman filter algorithm issuccessfully applied to resolve the overlapped absorption curves and therefore makes the simultaneousdetermination of these metallic ions possible without tedious pretreatment.The proposed method isapplied to analyse the titled elements in synthetic samples and in environmental samples such as hair,fingernail and river water samples with satisfactory results.