东南极格罗夫山地区的土壤特征及其环境研究

The Grove Mountains, including 64 nunataks, is situated on an area about 3200km2 in the inland ice cap of east Antarctica in Princess Elizabeth land (72o20'-73°101S, 73°50'-75o40'E), between Zhongshan station and Dome A, about 450km away from Zhongshan station (69°22'S, 76°22'E). Many workers thought there was no pedogenesis in the areas because of the less precipitation and extreme lower temperature. However, during the austral summer in 1999-2000, the Chinaer 16 Antarctic expedition teams entered the inland East Antarctica and found three soil spots in the Southern Mount Harding, Grove Mountains, East Antarctica. It is the first case that soils are discovered in the inland in East Antarctica. Interestingly, the soils in this area show clay fraction migration, which is different from other cold desert soils. In addition, several moraine banks are discovered around the Mount Harding. The soil properties are discussed as below. Desert pavement commonly occurs on the three soil site surfaces, which is composed of pebbles and fragments formed slowly in typical desert zone. Many pebbles are subround and variegated. These pebbles are formed by abrasion caused by not only wind and wind selective transportation, but also salt weathering and thaw-freezing action on rocks. The wind blows the boulders and bedrocks with snow grains and small sands. This results in rock disintegration, paved on the soil surface, forming desert pavement, which protects the underground soil from wind-blow. The desert pavement is the typical feature in ice free zone in Antarctica. There developed desert varnish and ventifacts in this area. Rubification is a dominant process in cold desert Antarctic soils. In cold desert soils, rubification results in relatively high concentrations of Fed in soil profile. Stained depth increases progressively with time. The content of Fed is increasing up to surface in each profile. The reddish thin film is observed around the margin of mafic minerals such as biotite, hornblende, and magnetite in parent materials with the microscope analyzing on some soil profiles. So the Fed originates from the weathering of mafic minerals in soils. Accumulations of water-soluble salts, either as discrete horizons or dispersed within the soil, occur in the soil profiles, and the salt encrustations accumulate just beneath surface stones in this area. The results of X-ray diffraction analyses show that the crystalline salts consist of pentahydrite (MgSO4-5H2O), hexahydrite (MgSO4-6H2O), hurlbutite (CaBe2(PO4)2), bloedite (Na2Mg(S04)2-4H2O), et al., being mainly sulfate. The dominant cations in 1:5 soil-water extracts are Mg2+ and Na+, as well as Ca2+ and K+, while the dominant anion is SO42-, then NO3-, Cl- and HCO3-. There are white and yellowish sponge materials covered the stone underside surface, of which the main compounds are quartz (SiO2, 40.75%), rozenite (FeSOKkO, 37.39%), guyanaite (Cr2O3-1.5H2O, 9.30%), and starkeyite (MgSO4-4H2O, 12.56%). 4) The distribution of the clay fraction is related to the maximum content of moisture and salts. Clay fraction migration occurs in the soils, which is different from that of other cold desert soils. X-ray diffraction analyses show that the main clay minerals are illite, smectite, then illite-smectite, little kaolinite and veirniculite. Mica was changed to illite, even to vermiculite by hydration. Illite formed in the initial stage of weathering. The appearance of smectite suggests that it enriched in magnesium, but no strong eluviation, which belongs to cold and arid acid environment. 5) Three soil sites have different moisture. The effect moisture is in the form of little ice in site 1. There is no ice in site 2, and ice-cement horizon is 12 cm below the soil surface in site 3. Salt horizon is 5-10 cm up to the surface in Site 1 and Site 2, while about 26cm in site 3. The differentiation of the active layer and the permafrost are not distinct because of arid climate. The depth of active layer is about 10 cm in this area. Soils and Environment: On the basis of the characteristics of surface rocks, soil colors, horizon differentiation, salt in soils and soil depth, the soils age of the Grove Mountains is 0.5-3.5Ma. No remnants of glaciations are found on the soil sites of Mount Harding, which suggests that the Antarctic glaciations have not reached the soil sites since at least 0.5Ma, and the ice cap was not much higher than present, even during the Last Glacial Maximum. The average altitude of the contact line of level of blue ice and outcrop is 2050m, and the altitude of soil area is 2160m. The relative height deviation is about 110m, so the soils have developed and preserved until today. The parental material of the soils originated from alluvial sedimentary of baserocks nearby. Sporepollen were extracted from the soils, arbor pollen grains are dominant by Pinus and Betula, as well as a small amount Quercus, Juglans, Tilia and Artemisia etc. Judging from the shape and colour, the sporepollen group is likely attributed to Neogene or Pliocene in age. This indicates that there had been a warm period during the Neogene in the Grove Mountains, East Antarctica.

A new method of predicting of gas chromatographic retention indices for polychlorinated dibenzofurans (PCDFs)

A new method has been developed to describe the quantitative relationship between molecular structures of PCDFs and their gas chromatographic retention indices on a 30-m fused silica column coated with DB-5 stationary phase. The regression equation is derived with a multiple correlation coefficient greater than 0.9995. The highest residual is 20 index units. The standard deviation is less than 7 index units. Using this regression equation, the retention indices of PCDFs for which data is not available have also been predicted. (C) 2000 Elsevier Science Ltd. All rights reserved.

Separation of peptides by strong cation-exchange capillary electrochromatography

Separation of small peptides on ion-exchange capillary electrochromatography (IE-CEC) with strong cation-exchange packing (SCX) as stationary phase was investigated. It was observed that the number of theoretical plates for small peptides varied from 240 000 to 460 000/m, and the relative standard deviation for t(0) and the migration time of peptides were less than 0.57% and 0.27%, respectively for ten consecutive runs. Unusually high column efficiency has been explained by the capillary electrophoretic stacking and chromatofocusing phenomena during the injection and separation of positively charged peptides. The sample buffer concentration had a marked effect on the column efficiency and peak area of the retained peptides. The influences of the buffer concentration and pH value as well as the applied voltage on the separation were investigated. It has been shown that the electrostatic interaction between the positively charged peptides and the SCX stationary phase played a very important role in IE-CEC, which provided the different separation selectivity from those in the capillary electrophoresis and reversed-phase liquid chromatography. A fast separation of ten peptides in less than 3.5 min on IE-CEC by adoption of the highly applied voltage was demonstrated. (C) 2000 Elsevier Science B.V. All rights reserved.

Estimation of soil organic partition coefficients: from retention factors measured by soil column chromatography with water as eluent

The retention factors (k) of 104 hydrophobic organic chemicals (HOCs) were measured in soil column chromatography (SCC) over columns filled with three naturally occurring reference soils and eluted with Milli-Q water. A novel method for the estimation of soil organic partition coefficient (K-oc) was developed based on correlations with k in soil/water systems. Strong log K-oc versus log k correlations (r>0.96) were found. The estimated K-oc values were in accordance with the literature values with a maximum deviation of less than 0.4 log units. All estimated K-oc values from three soils were consistent with each other. The SCC approach is promising for fast screening of a large number of chemicals in their environmental applications. (C) 2002 Elsevier Science B.V. All rights reserved.

Algebraic approach to stretching vibrational spectrum of H2S

The stretching vibrational spectra of H2S have been calculated by using the algebraic model, and the local mode characteristics have been analyzed. Within the vibrational quanta v=5, the standard deviation is 1.71 cm(-1), which is better than that from the local model HCAO model calculation.

不同干扰条件下社会认知偏离者两半球协同功能研究

Previous studies have witnessed some psychological or behavioral deviation (such as aggressive behavior) might have an association with cerebral hemisphere cooperative dysfunction, however, it is still unclear whether there is an association between individuals with social cognitive bias and their hemispheric cooperative functions especially while the interhemisphere cooperative processing is under the conditions of emotional interferences. The purpose of this study is to explore the differences between the social cognitive bias group and the normal group’s interhemispheric cooperative functional activity under the conditions of with or without interferences. Methods: According to Dodge’s (1993) model of “social-cognitive mechanisms in the development of conduct disorder and depression”, a 51 items of “social cognitive bias scale” was created and was used to screen the high score group. 20 male subjects was composed of high score group and other 23 matched the control group. Stimulus tachistoscopically presented to the bilateral visual field and compared with the central. Both group’s interhemispheric cooperative functional activity were observed and compared under the conditions of without interference- i.e. base level and with the emotional interferences of white noise level and negative evaluative feedback speech level while finishing: experiment one: Chinese word-figure Stroop analogue task; experiment two: two single Chinese Characters combination task. Heart rate and respiratory rate were simultaneously recorded as index of emotional changes. Results: ① The high score group showed a decrease in processing accuracy compared with the normal group under the condition of white noise interference level in experiment one. ② Still under the condition of white noise interference level, there were more reaction time and more errors were observed in high score group than normal in experiment two. ③ Both groups showed speed up effect and the strategic processing tendency of speed-accuracy trade-off effect under the condition of white noise interference level in both experiments. ④ Between group differences of interhemipheric cooperative function were not observed under the conditions of base level and the negative evaluative feedback speech level within both experiments. Conclusion: The results suggested that interhemispheric cooperative functional differences exists between the two groups, characterized as ① differences existed in interhemispheric cooperative processing strategy between the two groups, with the high score group presented “hierarchic” deficiency strategy. ② the appearance of the differences between the two groups were condition specified , and in this research it was only under the white noise interference condition. ③ the features of the differences between the two groups were the differences on multidimensional performances and with a deficit orientation in high score group. ④ the varieties of the differences were changing with cooperative tasks, as in this research the high score group performed worse in complementary cooperative task. In addition, both group adjusted the processing strategy respectively under the condition of white noise evoked emotional interference implied that the interaction between the interhemisphere cooperative processing and emotion might exist.

情绪干扰下焦虑水平对执行抑制的影响机制——事件相关电位研究

Behavioral inhibition model suggests the generation of anxiety is related with over-inhibition. For knowing about anxiety better, we used event-related potential (ERP) technique to explore the underlying mechanism of executive inhibition under the emotional distracter in high and low trait-anxious groups. Firstly, we set up the Chinese affective picture system (CAPS) as the stimuli of subsequent experiments. Secondly, we screened the high and low trait-anxious participants using the State-Trait Anxiety Inventory. In the first ERP study, a modified oddball paradigm was used with the positive, neutral and negative pictures as novel stimuli and the potentials evoked by three types pictures were analyzed. In the second ERP study, the same paradigm with higher task load was employed to examine the interaction of anxious level and emotion. Main results as follows: 1. CAPS consisted of 852 pictures was assessed via three dimensionalities, valence, arousal and dominance. The standard deviation of scores on valence and dominance was more than the standard deviation of scores on dimension of arousal. Scatter plot showed that the score distributing on the dimension of valence and arousal was wide in CAPS. 2. In both high and low trait-anxiety groups, the amplitudes of N2 and P3 of negative pictures were greater and smaller respectively as compared with neutral and positive pictures, which suggested all participants no matter what anxious level required more inhibition processing to negative information than others. 3. With increasing of task load, the P3 amplitudes of negative pictures in high anxious group were reduced relative to neutral pictures. In addition, in high anxious group, the P3 amplitudes of positive pictures had the same changes as those of negative ones. Whereas, the reduced P3 of positive pictures were not observed in low anxious group. The results showed the high anxious participants employed the same inhibitory strategy to the positive distracter as the negative distracter, which possibly the over-inhibition processing was involved in this group. 4. Dipole source analysis found cingulate may be involved in executive inhibition processing. In sum, as for the inhibition, high and low anxious group both is sensitive to negative information. However, in the high load situation, due to the shortness of cognitive resources, the high anxious individual represents the general sensitivity to all emotional information. These results gave the electrophysiological evidence for over-inhibition in high trait-anxiety group.

运动与重定向时物-我、物-物空间表征的使用

Eight experiments tested how object array structure and learning location influenced the establishing and utilization of self-to-object and object-to-object spatial representations in locomotion and reorientation. In Experiment 1 to 4, participants learned either at the periphery of or amidst regular or irregular object array, and then pointed to objects while blindfolded in three conditions: before turning (baseline), after rotating 240 degrees (updating), and after disorientation (disorientation). In Experiment 5 to 8, participants received instruction to keep track of self-to-object or object-to-object spatial representations before rotation. In each condition, the configuration error, which means the standard deviation of the means per target object of the signed pointing errors, was calculated as the index of the fidelity of representation used in each condition. Results indicate that participants form both self-to-object and object-to-object spatial representations after learning an object-array. Object-array structure influences the selection of representation during updating. By default, object-to-object spatial representation is updated when people learned the regular object-array structure, and self-to-object spatial representation is updated when people learned the irregular object array. But people could also update the other representation when they are required to do so. The fidelity of representations will confine this kind of “switch”. People could only “switch” from a low fidelity representation to a high fidelity representation or between two representations of similar fidelity. They couldn’t “switch” from a high fidelity representation to a low fidelity representation. Leaning location might influence the fidelity of representations. When people learned at the periphery of object array, they could acquire both self-to-object and object-to-object spatial representations of high fidelity. But when people learned amidst the object array, they could only acquire self-to-object spatial representation of high fidelity, and the fidelity of object-to-object spatial representation was low.

社会形势预警的几种建模方法比较

Based on social survey data conducted by local research group in some counties executed in the nearly past five years in China, the author proposed and solved two kernel problems in the field of social situation forecasting: i) How can the attitudes’ data on individual level be integrated with social situation data on macrolevel; ii) How can the powers of forecasting models’ constructed by different statistic methods be compared? Five integrative statistics were applied to the research: 1) algorithm average (MEAN); 2) standard deviation (SD); 3) coefficient variability (CV); 4) mixed secondary moment (M2); 5) Tendency (TD). To solve the former problem, the five statistics were taken to synthesize the individual and mocrolevel data of social situations on the levels of counties’ regions, and form novel integrative datasets, from the basis of which, the latter problem was accomplished by the author: modeling methods such as Multiple Regression Analysis (MRA), Discriminant Analysis (DA) and Support Vector Machine (SVM) were used to construct several forecasting models. Meanwhile, on the dimensions of stepwise vs. enter, short-term vs. long-term forecasting and different integrative (statistic) models, meta-analysis and power analysis were taken to compare the predicting power of each model within and among modeling methods. Finally, it can be concluded from the research of the dissertation: 1) Exactly significant difference exists among different integrative (statistic) models, in which, tendency (TD) integrative models have the highest power, but coefficient variability (CV) ones have the lowest; 2) There is no significant difference of the power between stepwise and enter models as well as short-term and long-term forecasting models; 3) There is significant difference among models constructed by different methods, of which, support vector machine (SVM) has the highest statistic power. This research founded basis in all facets for exploring the optimal forecasting models of social situation’s more deeply, further more, it is the first time methods of meta-analysis and power analysis were immersed into the assessments of such forecasting models.

Computer Perception of Three-Dimensional Objects

We first pose the following problem: to develop a program which takes line-drawings as input and constructs three-dimensional objects as output, such that the output objects are the same as the ones we see when we look at the input line-drawing. We then introduce the principle of minimum standard-deviation of angles (MSDA) and discuss a program based on MSDA. We present the results of testing this program with a variety of line- drawings and show that the program constitutes a solution to the stated problem over the range of line-drawings tested. Finally, we relate this work to its historical antecedents in the psychological and computer-vision literature.

Parallel Computation of Vernier Offsets, Curvature and Chevrons in Humans

A vernier offset is detected at once among straight lines, and reaction times are almost independent of the number of simultaneously presented stimuli (distractors), indicating parallel processing of vernier offsets. Reaction times for identifying a vernier offset to one side among verniers offset to the opposite side increase with the number of distractors, indicating serial processing. Even deviations below a photoreceptor diameter can be detected at once. The visual system thus attains positional accuracy below the photoreceptor diameter simultaneously at different positions. I conclude that deviation from straightness, or change of orientation, is detected in parallel over the visual field. Discontinuities or gradients in orientation may represent an elementary feature of vision.

Modification of a poly(methyl methacrylate) injection-molded microchip and its use for high performance analysis of DNA

Inexpensive and permanently modified poly(methyl methacrylate)(PMMA) microchips were fabricated by an injection-molding process. A novel sealing method for plastic microchips at room temperature was introduced. Run-to-run and chip-to-chip reproducibility was good, with relative standard deviation values between 1-3% for the run-to-run and less than 2.1% for the chip-to-chip comparisons. Acrylonitrile-butadiene-styrene (ABS) was used as an additive in PMMA substrates. The proportions of PMMA and ABS were optimized. ABS may be considered as a modifier, which obviously improved some characteristics of the microchip, such as the hydrophilicity and the electro-osmotic flow (EOF). The detection limit of Rhodamine 6G dye for the modified microchip on the home-made microchip analyzer showed a dramatic 100-fold improvement over that for the unmodified PMMA chip. A detection limit of the order of 10(-20) mole has been achieved for each injected phiX-174/HaeIII DNA fragment with the baseline separation between 271 and 281 bp, and fast separation of 11 DNA restriction fragments within 180 seconds. Analysis of a PCR product from the tobacco ACT gene was performed on the modified microchip as an application example.

Rapid authentication of ginseng species using microchip electrophoresis with laser-induced fluorescence detection

Ginseng is one of the most expensive Chinese herbal medicines and the effectiveness of ginseng depends strongly on its botanical sources and the use of different parts of the plants. In this study, a microchip electrophoresis method coupled with the polymerase chain reaction (PCR)-short tandem repeats (STR) technique was developed for rapid authentication of ginseng species. A low viscosity hydroxypropyl methylcellulose (HPMC) solution was used as the sieving matrix for separation of the amplified STR fragments. The allele sizing of the amplified PCR products could be detected within 240 s or less. Good reproducibility and accuracy of the fragment size were obtained with the relative standard deviation for the allele sizes less than 1.0% (n = 11). At two microsatellite loci (CT 12, CA 33), American ginseng had a different allele pattern on the electropherograms compared with that of the Oriental ginseng. Moreover, cultivated and wild American ginseng can be distinguished on the basis of allele sizing. This work establishes the feasibility of fast genetic authentication of ginseng species by use of microchip electrophoresis.

Determination of heat capacities and thermodynamic properties of 2-(chloromethylthio)benzothiazole by an adiabatic calorimeter

The molar heat capacities of 2-(chloromethylthio)benzothiazole (molecular formula C8H6ClNS2, CA registry no. 28908-00-1) were measured with an adiabatic calorimeter in the temperature range between (80 and 350) K. The construction and procedures of the calorimeter were described in detail. The performance of the calorimetric apparatus was evaluated by heat capacity measurements on alpha-Al2O3. The deviation of experiment heat capacities from the corresponding smoothed values lies within 0.3%, whereas the uncertainty is within +/-0.5%, compared with that of the recommended reference data over the whole experimental temperature range. A fusion transition was found from the C-p-T curve of 2-(chloromethylthio)benzothiazole. The melting temperature and the molar enthalpy and entropy of fusion of the compound were determined to be T-m = (315.11 +/- 0.04) K, Delta(fus)H(m) = (17.02 +/- 0.03) kJ(.)mol(-1), and Delta(fus)S(m) = (54.04 +/- 0.05) J(.)mol(-1.)K(-1), respectively. The thermodynamic functions (H-T - H-298.15) and (S-T - S-298.15) were also derived from the heat capacity data. The molar fraction purity of the 2-(chloromethylthio)benzothiazole sample used in the present calorimetric study was determined to be 99.21 by fraction melting.

Determination of organophosphorus pesticides in cucumber and potato by stir bar sorptive extraction

Organophosphorus pesticides (OPPs) in vegetables were determined by stir bar sorptive extraction (SBSE) and capillary gas chromatography with thermionic specific detection (TSD). Hydroxy-terminated polydimethylsioxane (PDMS) prepared by sol-gel method was used as extraction phase. The effects of extraction temperature, salting out, extraction time on extraction efficiency were studied. The detection limits of OPPs in water were <= 1.2 ng/l. This method was also applied to the analysis of OPPs in vegetable samples and matrix effect was studied. Linear ranges of OPPs in vegetable samples were 0.05-50 ng/g with detection limits <= 0. 15 ng/g and the repeatability of the method was less than 20% relative standard deviation. (c) 2005 Elsevier B.V. All rights reserved.