Characterization of saccharides and phenolic acids in the Chinese herb Tanshen by ESI-FT-ICR-MS and HPLC

This study sought to determine the main components (saccharides and phenolic acids) in crude extract of the Chinese herb Tanshen by electrospray ionization Fourier transform ion cyclotron resonant mass spectrometry (ESI-FT-ICR-MS) in negative-ion mode. Eleven compounds were identified as phenolic acids by exact mass measurement and further confirmed by sustained off-resonance irradiation (SORI) CID data. In addition, monosaccharicles and oligosaccharides (n = 2 similar to 5) and a serial of corresponding anionic adducts of saccharide were observed without adding any anions additionally to the extract solution, and the anionic components were unambiguously identified as H2O, HCl, HCOOH, HNO3, C3H6O2, H2SO4 and C5H7NO3 according to the exact mass measurement results.

Synthesis, characterization and optical property of flower-like indium tin sulfide nanostructures

We report a simple method for novel flower-like In4SnS8 nanostructure synthesis. A flower-like In4SnS8 nanostructure was synthesized via a one-pot hydrothermal route using the biomolecule L-cysteine as a sulfur source. The structure was characterized using X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption analysis and photoluminescence spectra. This flower-like structure consists of crosslinked nanoflakes and possesses good thermostability and a high BET surface area.

Nanocrystalline LaGaO3 : Tm3+ as an efficient blue phosphor for field emission displays with high color purity

Nanocrystalline Tm3+-doped LaGaO3 phosphors were prepared through a Pechini-type sol-gel process [M. P. Pechini, U.S. Patent No. 3,330,697 (11 July 1967)]. X-ray diffraction, field emission scanning electron microscopy, photoluminescence, and cathodoluminescence (CL) spectra were utilized to characterize the synthesized phosphors. Under the excitation of ultraviolet light and low voltage electron beams (0.5-3 kV), the Tm3+-doped LaGaO3 phosphors show the characteristic emissions from the LaGaO3 host lattice and the Tm3+ (D-1(2), (1)G(4)-F-3(4), and H-3(6) transitions), respectively. The blue CL of the Tm3+-doped LaGaO3 phosphors, with a dominant wavelength of 458 nm, had better Commission International I'Eclairage chromaticity coordinates (0.1552, 0.0630) and higher emission intensity than the commercial product (Y2SiO5:Ce3+).

Sol-ogel deposition and luminescence properties of lanthanide ion-doped Y2(1-x)Gd2xSiWO8 (0 <= x <= 1) phosphor films

Y2(1-x) Gd2xSiWO8 : A ( 0 <= x <= 1; A= Eu3+, Dy3+, Sm3+, Er3+) phosphor films have been prepared on silica glass substrates through the sol - gel dip-coating process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), atomic force microscope (AFM), scanning electron microscopy (SEM) and photoluminescence spectra as well as lifetimes were used to characterize the resulting films. The results of the XRD indicated that the films began to crystallize at 800 degrees C and crystallized completely at 1000 degrees C. The AFM and SEM study revealed that the phosphor films, which mainly consisted of closely packed grains with an average size of 90 - 120 nm with a thickness of 660 nm, were uniform and crack free. Owing to an efficient energy transfer from the WO42- groups to the activators, the doped lanthanide ion ( A) showed its characteristic f - f transition emissions in crystalline Y2(1-x) Gd2xSiWO8 (0 <= x <= 1) films. The optimum concentrations for Eu3+, Dy3+, Sm3+, Er3+ were determined to be 21, 5, 3 and 7 mol% of Y3+ in Y2SiWO8 films, respectively.

Characterization of the structural and functional changes of hemoglobin in dimethyl sulfoxide by spectroscopic techniques

Circular dichroism (CD), fourier transform infrared (FTIR), and fluorescence spectroscopy were used to explore the effect of dimethyl sulfoxide (DMSO) on the structure and function of hemoglobin (Hb). The native tertiary structure was disrupted completely when the concentration of DMSO reached 50% (v/v), which was determined by loss of the characteristic Soret CD spectrum. Loss of the native tertiary structure could be mainly caused by breaking the hydrogen bonds, between the heme propionate groups and nearby surface amino acid residues, and by disorganizing the hydrophobic interior of this protein. Upon exposure of Hb to 52% DMSO for ca. 12 h in a D2O medium no significant change in 1652 cm(-1) band of the FTIR spectrum was produced, which demonstrated that alpha-helical structure predominated. When the concentration of DMSO increased to 57%: (1) the band at 1652 cm(-1) disappeared with the appearance of two new bands located at 1661 and 1648 cm(-1); (2) another new band at 1623 cm(-1) was attributed to the formation of intermolecular beta-sheet or aggregation, which was the direct consequence of breaking of the polypeptide chain by the competition of S=O groups in DMSO with C=O groups in amide bonds. Further increasing the DMSO concentration to 80%, the intensity at 1623 cm(-1) increased, and the bands at 1684, 1661 and 1648 cm(-1) shifted to 1688, 1664 and 1644 cm(-1), respectively. These changes showed that the native secondary structure of Hb was last and led to further aggregation and increase of the content of 'free' amide C=O groups. In pure DMSO solvent, the major band at 1664 cm(-1) indicated that almost all of both the intermolecular beta-sheet and any residual secondary structure were completely disrupted. The red shift of the fluorescence emission maxima showed that the tryptophan residues were exposed to a greater hydrophilic environment as the DMSO content increased. GO-binding experiment suggested that the biological function of Hb was disrupted seriously even if the content of DMSO was 20%. (C) 1998 Elsevier Science B.V. All rights reserved.

渤海南部海域沉积物-海水界面附近磷、硅赋存形态及其生物地球化学过程研究

本文系统研究了渤海南部海域沉积物-海水界面附近（包括上覆水、悬浮颗粒物和沉积物）P、Si的赋存形态及其生物地球化学过程。其特色在于提出了“自然粒度下形态研究”的概念，探讨了能真正参与循环的P、Si及其控制关键环节，为渤海资源特别是生物资源的可持续利用战略的制定提供理论基础。得到的主要结论包括：研究了渤海南部海域覆水、悬浮颗粒物中P、Si的变异特征。上覆水体PO_4-P、SiO_3-Si的平均含量均低于大洋底层水PO_4-P、SiO_3-Si的平均含量。悬浮颗粒物中TIP、BP的来源和循环控制机制不同，TISi、BSi有一定的相似性。稀释作用和表层沉积物中可交换态P、Si的循环控制上覆水体中P、Si的地球化学行为。颗粒物中TIP、TISi的行为受离子交换和化学吸附过程影响，其中化学吸附可能与Fe（III）的氧化物有关；生物过程对颗粒物中生源P、Si的地球化学行为有重要影响。渤海南部海域沉积物P、Si的分布特征及其成岩过程研究表明。表层沉积物可交换态磷中，OSF-P是磷的优势赋存形态，占总磷的10.7%；CF-Si是硅的优势赋存形态，占总硅的0.05%。 不同形态P的成岩过程有一定的相似性。TSi与其它相中的Si呈负相关或不呈显著相关，且可交换态Si的量仅占总Si的0.12%以下，说明以往采用测定总Si含量来研究Si的生物地球化学过程不可能得出有价值的信息。IMOF-P、OSF-P、IMOF-Si、CF-Si在P、Si的生物地球化学循环中有重要作用。CaCO_3、Fe（III）和Corg等对P、Si界面循环有重要影响，有机质的钙化导OSF-P的矿化作用而释放P；Fe（III）的还原引起IMOF-P， CF-P和CF-Si对P、Si的释放。Corg的成岩过程对CF-Si有影响。约79%的BP和75%的BSi沉积后转化为相对稳定状态，在较短时间内不再参与循环。柱状沉积物中，OSF-P和CF-P之间存在沉积转化。CF-Si呈双指数分布。P、Si在表层沉积物中垂向分布的差异，表明底栖生物扰动对加强界面P、Si交换的作用。室内模拟沉积物-海水界面附近P、Si交换过程表明，P、Si在沉积物、上覆海水间的交换通量分别为0.8μ mol/ (m~2 · h)。P、Si的埋藏与释放主要受OSF-P、IMOF-Si 和平共处BSi的影响。对渤海P、Si年循环的估算显示，P在渤海湾、莱州湾的年循环量达30.9 * 10~5kg 和13.8 * 10~5kg， Si则分别为22.8 * 10~7 kg和15.5 * 10~7 kg，这其中沉积物向上覆海水扩散的P占87.7%和87.0%， Si占22.4%和14.2%。就整个渤海而言，沉积物向海水释放的磷、硅在其总循环中分别占88.7%和34.0%，所以沉积物-海水界面过程对磷、硅在渤海的生物地球化学循环有重要影响，是渤海P、Si循环的关键控制过程之一。

CIMS环境下的使能器技术及其应用

本文阐述了ＣＩＭＳ中异构分布式数据库环境下基于并行客户／服务器结构的使能器技术、功能及其结构。并讨论了使能器技术在ＣＩＭＳ环境下的应用研究。

叠前时间偏移：各向异性、多次波衰减及应用

At present, in order to image complex structures more accurately, the seismic migration methods has been developed from isotropic media to the anisotropic media. This dissertation develops a prestack time migration algorithm and application aspects for complex structures systematically. In transversely isotropic media with a vertical symmetry axis (VTI media), the dissertation starts from the theory that the prestack time migration is an approximation of the prestack depth migration, based on the one way wave equation and VTI time migration dispersion relation, by combining the stationary-phase theory gives a wave equation based VTI prestack time migration algorithm. Based on this algorithm, we can analytically obtain the travel time and amplitude expression in VTI media, as while conclude how the anisotropic parameter influence the time migration, and by analyzing the normal moveout of the far offset seismic data and lateral inhomogeneity of velocity, we can update the velocity model and estimate the anisotropic parameter model through the time migration. When anisotropic parameter is zero, this algorithm degenerates to the isotropic time migration algorithm naturally, so we can propose an isotopic processing procedure for imaging. This procedure may keep the main character of time migration such as high computational efficiency and velocity estimation through the migration, and, additionally, partially compensate the geometric divergence by adopting the deconvolution imaging condition of wave equation migration. Application of this algorithm to the complicated synthetic dataset and field data demonstrates the effectiveness of the approach. In the dissertation we also present an approach for estimating the velocity model and anisotropic parameter model. After analyzing the velocity and anisotropic parameter impaction on the time migration, and based on the normal moveout of the far offset seismic data and lateral inhomogeneity of velocity, through migration we can update the velocity model and estimate the anisotropic parameter model by combining the advantages of velocity analysis in isotropic media and anisotropic parameter estimation in VTI media. Testing on the synthetic and field data, demonstrates the method is effective and very steady. Massive synthetic dataset、2D sea dataset and 3D field datasets are used for VTI prestack time migration and compared to the stacked section after NMO and prestack isotropic time migration stacked section to demonstrate that VTI prestack time migration method in this paper can obtain better focusing and less positioning errors of complicated dip reflectors. When subsurface is more complex, primaries and multiples could not be separated in the Radon domain because they can no longer be described with simple functions (parabolic). We propose an attenuating multiple method in the image domain to resolve this problem. For a given velocity model，since time migration takes the complex structures wavefield propagation in to account, primaries and multiples have different offset-domain moveout discrepancies, then can be separated using techniques similar to the prior migration with Radon transform. Since every individual offset-domain common-reflection point gather incorporates complex 3D propagation effects, our method has the advantage of working with 3D data and complicated geology. Testing on synthetic and real data, we demonstrate the power of the method in discriminating between primaries and multiples after prestack time migration, and multiples can be attenuated in the image space considerably.

贵阳市环境中多环芳烃的研究

多环芳烃(PAHs)是两个或两个以上苯环连接在一起的烃类化合物;环境中它主要来源于煤、石油、木材、有机高分子化合物、烟草和其他碳氢化合物的不完全燃烧.PAHs在环境中无处不在,且具有致癌性、致畸性、致突变性,生物累积性使它能长期滞留在环境中.因此PAHs的研究受到了环境工作者的极大关注.准确把握环境中多环芳烃的行为、主要来源及归宿,对有效控制污染、保护人类健康有非常重要的意义.

Minimizing Statistical Bias with Queries

I describe an exploration criterion that attempts to minimize the error of a learner by minimizing its estimated squared bias. I describe experiments with locally-weighted regression on two simple kinematics problems, and observe that this "bias-only" approach outperforms the more common "variance-only" exploration approach, even in the presence of noise.

Prediction of soil organic partition coefficients by a soil leaching column chromatographic method

The soil organic partition coefficient (K-oc) is one of the most important parameters to depict the transfer and fate of a chemical in the soil-water system. Predicting K-oc by using a chromatographic technique has been developing into a convenient and low-cost method. In this paper, a soil leaching column chromatograpy (SLCC) method employing the soil column packed with reference soil GSE 17201 (obtained from Bayer Landwirtschaftszentrum, Monheim, Germany) and methanol-water eluents was developed to predict the K-oc of hydrophobic organic chemicals (HOCs), over a log K-oc range of 4.8 orders of magnitude, from their capacity factors. The capacity factor with water as an eluent (k(w)') could be obtained by linearly extrapolating capacity factors in methanol-water eluents (k') with various volume fractions of methanol (phi). The important effects of solute activity coefficients in water on k(w)' and K-oc were illustrated. Hence, the correlation between log K-oc and log k(w)' (and log k') exists in the soil. The correlation coefficient (r) of the log K-oc vs. log k(w)' correlation for 58 apolar and polar compounds could reach 0.987, while the correlation coefficients of the log K-oc-log k' correlations were no less than 0.968, with phi ranging from 0 to 0.50. The smaller the phi, the higher the r. Therefore, it is recommended that the eluent of smaller phi, such as water, be used for accurately estimating K-oc. Correspondingly, the r value of the log K-oc-log k(w)' correlation on a reversed-phase Hypersil ODS (Thermo Hypersil, Kleinostheim, Germany) column was less than 0.940 for the same solutes. The SLCC method could provide a more reliable route to predict K-oc indirectly from a correlation with k(w)' than the reversed-phase liquid chromatographic (RPLC) one.

Plano de exploração sob critérios de manejo florestal de baixo impacto.

A exploração florestal convencional infelizmente tem objetivos de curto prazo. O resultado final é uma diminuição da área útil de manejo com possibilidades de regeneração. Normas que contemplam uma intervenção de baixo impacto, em povoamento de floresta nativa, podem garantir uma maior certeza na sustentabilidade do manejo florestal.

Competitive advantage revisited: Michael Porter on strategy and competitiveness.

Strategic management is constantly evolving as both an academic discipline and as a reflection of management practice. This article, based on a recent interview with Michael Porter, assesses his contribution to the development of the discipline in the context of the advances that have taken place since the publication of his seminal work Competitive Strategy in 1980. The authors conclude that Porter has made major lasting contributions to strategy, increasing both its academic rigor and its accessibility to managers. The article and interview place Porter's work at the center of the development of strategic management in terms of the provision of practical analytical frameworks, transforming it into a recognized and recognizable field of academic study and management practice. This feat of transformation has not been equaled before or since, so that 25 years after his first seminal contribution, Porter's work continues to provide remarkable insights into the nature of competition and strategy.