Substitution Matrices of Residue Triplets Derived from Protein Blocks.

In protein sequence alignment, residue similarity is usually evaluated by substitution matrix, which scores all possible exchanges of one amino acid with another. Several matrices are widely used in sequence alignment, including PAM matrices derived from homologous sequence and BLOSUM matrices derived from aligned segments of BLOCKS. However, most matrices have not addressed the high-order residue-residue interactions that are vital to the bioproperties of protein.With consideration for the inherent correlation in residue triplet, we present a new scoring scheme for sequence alignment. Protein sequence is treated as overlapping and successive 3-residue segments. Two edge residues of a triplet are clustered into hydrophobic or polar categories, respectively. Protein sequence is then rewritten into triplet sequence with 2 · 20 · 2 = 80 alphabets. Using a traditional approach, we construct a new scoring scheme named TLESUMhp (TripLEt SUbstitution Matrices with hydropobic and polar information) for pairwise substitution of triplets, which characterizes the similarity of residue triplets. The applications of this matrix led to marked improvements in multiple sequence alignment and in searching structurally alike residue segments. The reason for the occurrence of the ‘‘twilight zone,’’ i.e., structure explosion of lowidentity sequences, is also discussed.

Characteristics of plasma induced by interaction of a free-oscillated laser pulse with a coal target in air and combustible gas

Plasma in the air is successfully induced by a free-oscillated Nd:YAG laser pulse with a peak power of 10(2-3) W. The initial free electrons for the cascade breakdown process are from the ablated particles from the surface of a heated coal target, likewise induced by the focused laser beam. The laser field compensates the energy loss of the plasma when the corresponding temperature and the images are investigated by fitting the experimental spectra of B-2 Sigma(+) -> X-2 Sigma(+) band of CN radicals in the plasma with the simulated spectra and a 4-frame CCD camera. The electron density is estimated using a simplified Kramer formula. As this interaction occurs in a gas mixture of hydrogen and oxygen, the formation and development of the plasma are weakened or restrained due to the chaining branch reaction in which the OH radicals are accumulated and the laser energy is consumed. Moreover, this laser ignition will initiate the combustion or explosion process of combustible gas and the minimum ignition energy is measured at different initial pressures. The differences in the experimental results compared to those induced by a nanosecond Q-switched laser pulse with a peak power of 10(6-8) W are also discussed. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

Extinction of lean near-limit methane/air flames at elevated pressures under normal- and reduced-gravity

perimentally at evaluated pressures and under normal- and micro-gravity conditions utilizing the 3.5 s drop tower of the National Microgravity Laboratory of China. The results showed that under micro-gravity conditions the natural convection is minimized and the flames become more planar and symmetric compared to normal gravity. In both normal- and micro-gravity experiments and for a given strain rate and fuel concentration, the flame luminosity was found to enhance as the pressure increases. On the other hand, at a given pressure, the flame luminosity was determined to weaken as the strain rate decreases. At a given strain rate, the fuel concentration at extinction was found to vary non-monotonically with pressure, namely it first increases and subsequently decreases with pressure. The limit fuel concentration peaks around 3 and 4 atm under normal- and micro-gravity, respectively. The extinction limits measured at micro-gravity were in good agreement with predictions obtained through detailed numerical simulations but they are notably lower compared to the data obtained under normal gravity. The simulations confirmed the non-monotonic variation of flammability limits with pressure, in agreement with previous studies. Sensitivity analysis showed that for pressures between one and 5 atm, the near-limit flame response is dominated by the competition between the main branching, H + O2 ? OH + O, and the pressure sensitive termination, H+O2+M? HO2 + M, reaction. However, for pressures greater than 5 atm it was determined that the HO2 kinetics result in further chain branching in a way that is analogous to the third explosion limit of H2/O2 mixtures. 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

低渗透油田层内爆炸增产技术研究进展

系统介绍了层内爆炸增产技术的技术思路,应用前景以及实现该技术所涉及到的一系列关键性技术问题;详细介绍了近年来针对此项技术所开展的一系列研究工作,报告了取得的一些研究成果,并对今后的主要研究工作做了展望

Experimental Setup for Assessing the Energetic Materials Deflagration Propagation under High Temperature and High Pressure Conditions

The technology of "explosion in fractures" is one of new synthetic engineering methods used in low permeability reservoirs. The most important problem arose from the technology is to assess the deflagration propagation capability of milky explosives in rock fractures. In order to investigate detailed this problem in the laboratory, an experimental setup was designed and developed in which different conditions can be simulated. The experimental setup mainly includes two parts. One is the experimental part and the other is the measurement part. In the experimental setup, the narrow slots with different width can be simulated; meanwhile, different initial pressures and initial temperatures can be loaded on the explosives inside the narrow slots. The initial pressure range is from 0-60 MPa, and the initial temperatures range is from room temperature to 100 V. The temperature and the velocity of deflagration wave can be measured; meanwhile the corresponding pressure in the narrow slot is also measured. In the end, some typical measurement results are briefly presented and discussed.

岩体中爆腔内压力脉动特征和爆炸能量分布的数值模拟

分析了对岩体中爆炸能量分布和爆腔内压力研究的现状, 为进行这方面的研究, 在块体离散元基础上独立开发了可变形多尺度计算模型和爆源模型, 改进后的数值模型适合研究爆源近区的爆炸效应. 通过该模型对岩体中爆腔内压力和爆炸能量分布进行了数值模拟, 分析了爆腔内压力脉动特征, 指出爆源近区岩体结构性质对爆腔内压力脉动规律影响不大, 爆腔内压力峰值与炸药量无关; 结合热力学和弹性力学知识分析了不同条件下爆炸能量分布规律, 研究了岩体破坏对爆炸能量分布的影响, 给出了岩石断裂破坏消耗能量、变形能、用于抛掷的能量的比例

Study on peak overpressure and flame propagation speed of gas deflagration in the tube with obstacles

The on-way peak overpressure and flame propagation speed of gas deflagration in the tube with obstacles are important data for process safety. Based on carbon monoxide deflagration experiments, the paper presents a multi-zone integration model for calculation of on-way peak overpressure, in which the tube with obstacles is considered as a series of venting explosion enclosures which link each others. The analysis of experimental data indicates that the on-way peak overpressure of gas deflagration can be correlated as an empirical formula with equivalence ratio of carbon monoxide oxidation, expansion ratio, flame path length, etc., and that the on-way peak overpressure exhibits a linear relationship with turbulence factor and flame propagation speed. An empirical formula of flame propagation speed is given.

Cluster assistant generation of C2+ and C3+ ions in nanosecond laser ionization of seeded benzene beam

Cluster assisted photoionization processes of benzene, which was seeded in argon, induced by an intense 25 ns Nd-YAG laser has been studied by means of time-of-flight mass spectrometry. At the laser intensity of 10(11) W/cm(2), multicharged ions Cq+ (q = 2-3) with kinetic energy up to 150 eV were observed in the mass spectra. Strong evidences Support that these ions are formed in the Coulomb explosion of multicharged benzene cluster ions. (C) 2004 Elsevier B.V. All rights reserved.

PREPARATION, CRYSTAL-STRUCTURE, AND VIBRATIONAL-SPECTRA OF PEROVSKITE-TYPE MIXED OXIDES LAM(Y)M'(1-Y)O(3) (M,M'=MN, FE, CO)

Three series of samples LaMnyCo1-yO3+/-lambda, LaFeyMn1-yO3+/-lambda, and LaFeyCo1-yO3+/-lambda (y = 0.0 to 1.0) with Perovskite structure were prepared by an explosion method different from the generally used ceramic techniques. The variation of crystal

Extraction of phosphorus in natural waters and sediments by ignition method

Phosphorus recoveries from selected inorganic and organic P-containing compounds after ignition with auxiliaries, such as MgSO4, Mg (NO3)(2), MgCl2, Mg (Ac)(2) and CaCl2 were studied. It was found that the phosphorus could not be completely recovered when most P-containing compounds were ignited with MgSO4 at temperature not higher than 500degreesC if the baked residue was extracted with 0.2 mol/L HCl for 30 min at 80degreesC or at room temperature. In contrast, MgCl2, Mg(Ac)(2) and CaCl2, as well as Mg(NO3)(2), could all yield complete P recoveries. We suggest that MgCl2 rather than MgSO4, which is usually used, should be utilized as ashing auxiliary agent in the P extraction by ignition method. Although Mg (NO3)(2) is a highly effective auxiliary agent, yet interference from MgSO4, danger of explosion, toxicity of nitrogen dioxide and more manipulation steps may limit its widespread utilization. It is suggested that if sediment is ignited with MgCl2, the extraction of residue with 0.2 mol/L HCl for 30 min at 80degreesC could give good result.

企业间电子商务风险的综合分析方法

互连网上电子商务的蓬勃发展为企业提供了巨大商机，但风险也是巨大的。同时，网上信息爆炸也需要一种使用的方法对信息进行分析、整理、提取，为下一步的决策提供坚实的基础。本文在总结不同风险分析方法的基础上，提出了一种完整的方法，为网上商务的风险分析和决策提供了一种实用的解决方案。

地球介质非线性与各向异性的地震波响应及其成像效应

The practice of geophysical prospecting shows us the complex interior earth. The studies of the complexity play an important role and practical guide for the subsurface structure. At present, the complexity of the earth mainly means lateral and vertical homogeneity, anisotropy and non-linear quality. And the anisotropy and non-linear media studies become the frontier in seismology and exploration seismology. This paper summarizes the development of complexities and presents the forward and inverse in the non-linear and anisotropic media. Firstly, the paper introduces the theory of seismic wave propagation in the non-linear and anisotropic media, the theoretical basis for simulation and inversion research. Secondly, high quality numerical simulation method with little dispersion has been developed to investigate the influence of complexity including anisotropy and non-linear multi-component seismograms. Because most real data in seismology have a single component, we developed two aspects work on anisotropic multi-component imaging. One is prestack reflection migration. The result show that distorted images are obtained if data from anisotropic media are migrated using isotropic extrapolation. Moreover, image quality will be improved greatly after considering anisotropy in subsurface layers. The other one is the we take advantage of multi-component data to inversion of the anisotropic parameters jointly seimic reflection travel time and polarization information. Based on these research works, we get the following results: 1.Combing numerical simulation, systematical studies indicate that anisotropy and non-linear seismograms characters are significant to detect cracked belts in the earth and to understand deformation field and mechanism. 2.Based on anisotropic media models, we developed an efficient prestack migration method for subsurface structure and different observation methods seismic data, which improving the imaging quality with VSP, seismograms and real data. 3.Jointly seismic inversion combining seismic anisotropic reflection traveltimes and polarizations data show that the complete wrong inversion and the following explanation will be resulted by ignoring anisotropy.