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INVESTIGATION ON THE FLOW STABILITY OF NEWTONIAN FLUID IN ECCENTRIC ANNULUS VIA THE AXIAL RECIPROCATION OF THE INNER TUBE

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Journal of Hydrodynamics 2007年第6期19卷 671-676页

作者： YUAN Ai-wu CUI Hai-qing GAO Tao Management institute Tianjin University Tianjin 300072 China Department of Petroleum Engineering Daqing Petroleum Institute Daqing 163318 China Daqing Exploration and Development institute Daqing 163712 China

The governing equation, together with the formulas of the averaged flux and the stability parameter for Newtonian fluid flowing in eccentric annulus via the axial reciprocation of the inner tube was established in the bipolar coordinate system. Numerical calculation was conducted for the measurement of water flow using the formulas above, of which the results agree well with the experimental data. It is shown that the flow instability can be induced by the increase of the stroke, the frequency, and the eccentricity of annulus, making the sucker rod more susceptible to partial abrasion. Some protecting methods, including adding centralizers, adjusting the stroke and frequency, are proposed to protect the sucker rod from the partial abrasion, and satisfactory results have been achieved in the oilfields.

关键词： eccentric annulus axial reciprocation flow stability partial abrasion

Randomization of protein encoding gene during species evolution

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Chinese Science Bulletin 1998年第4期43卷 299-303页

作者： GE Weiwen 1 and HE Fuchu 2 1. institute of Hygiene and Environment Medicine, tianjin 300050, China 2. institute of Radiation Medicine, Beijing 100850, China institute of Hygiene and Environment Medicine Tianjin China institute of Radiation Medicine Beijing China

Employing chi_square test, the authors observed the bias of 4 kinds of bases’ locating in 3 codon positions in gene sequence, and proved that there is a positive correlation between higher chi_square value and protein coding structure. By this, the observation that genes undergo progressive reduction in chi_values along evolution direction will reflect the progressive randomization of gene structures and the loss of the characteristics of protein coding sequences. The result proposed that during the evolution of life, genes are unexpectedly degenerating.

关键词： chi_square test gene sequence randomization evolution.

Discussion　About　the　Paper　＂The　Eigen－Problem　of　Matrix　in　Max－Algebra－Analysis　for　Operating　Period　of　A　Class　of　DEDS＂

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Systems Science and Systems Engineering 1996年第1期6卷 87-89页

作者： WAN Liangqiao(Dept.of Management Engin.,tianjin institute of Technology,tianjin 300191,China)

In this paper,we discuss the contents of paper[l] with the authors,point out that the conclustions in paper[1] about the periodicity of any N ×N square matrix are inappropriate,and make some notes on the problem abou... 详细信息

关键词： max-algebra discrete-event dynamic system eigenvalue critical circuit irreducible matrix

Studies on Chiral Thiophosphoric Acids and Their Derivatives *** Asymmetric Cyclizations of L-prolinol with (Thio)phosphoro(-no)dichlorides

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Chinese Chemical Letters 1997年第2期8卷 97-98页

作者： Chu Chi TANG You Ming WANG Zheng Jie HE(institute of Elemento-Organic Chemistry, Nankai University, tianjin 300071) Inst. of Elemento-Organic Chemistry Nankai University Tianjin 300071 China

The cyclizations of L-(+)-prolinol 1 derived from L-proline with (thio)phosphoro(-no)dichlorides 2 give 1,2,3-azaphosphaoxabicyclo[3.3.0] 3 consisting of unequal amounts of diastereoisomers, eight pairs of which have ... 详细信息

关键词： Ru Studies on Chiral Thiophosphoric Acids and Their Derivatives 15.The Asymmetric Cyclizations of L-prolinol with Thio)phosphoro no)dichlorides

Crystal 　Structure　of　1　－Acetyl　－2－［O－methylphenyl）　phenyl－　thiophosphonyl］　Hydrazine

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Chinese Journal of Structural Chemistry 1996年第1期15卷 12-14页

作者： Zhang Li-Juan Liu Xiao-Lan Miao Fang-Ming (institute of Chemical Crystallography, tianjin Normal Universily, tianjin, 300074)Cai Jian-Ping Jin Gui-Yu Chen Ru-Yu (institute of Elemento-Organic Chemistry, Nankai Universily, tianjin, 300071) Inst. of Chemical Crystallography Tianjin Normal University Tianjin 300074 Inst. of Elemento-Organic Chemistry Nankai University Tianjin 300071

The crystals of the title compound C_(15)H_(17)N_2O_2PS were obtained by re crystallizing from ether-methanol solution. It belongs to the orthorhombic system, space group Pbca with a= 9. 255(1) , b= 17.189(8) , c =20. 446(4)A, V=3252.6 (7) A￣3, D_c=1. 31 g/cm￣3,Z= 8, μ(CuKa)=26. 87 cm-1, F(000)=1344. The structure was refined to R=0. 053, R_w=0. 055 for 1299 observed reflections (I≥3σ(I)). In the molecule P atom adopts distorted tetrahedral *** bond (II)distances of P-O, P-N and P-C are 1.605(1) A, 1. 657(1) A 1. 801(1)A,(III)respectively. The X-ray crystallographic analysis demonstrates that there are intramolecular and intermolecular hydrogen bonds in the structure.

关键词： thiophosphonyl hydrazine cyclization reaction crystal structure

DISCOVERY OF NEW FOSSIL SPIDERS IN AMBER OF FUSHUN COALFIELD

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Science in China,Ser.B 1982年第4期25卷 431-437页

作者：洪友崇 tianjin institute of Geology and Mineral Resources Ministry of Geology

A new genus, Sinodictyna （Archanda）, has been obtained from amber on the main coalbeds of the Gucheggzi Formation (E2g1), Fush?n Coalfield In Liaoning Province. It suggeststhat Sinodictyna belongs to a regional form in China and that it differs from European Balticamber Eolathys in the chelate teeth, pedipal, walking legs and its appendages. New genusdiscovered first in China fills in tlie gaps in the field of paleontology of China.

关键词： length

Novel Phosphonoacetic Acid *** of N-(Ethoxycarbonylmethylphosphonyl)-α-Amino Esters and-α-Amino Phosphonic Acid Esters and Their Bioactivities

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Chinese Chemical Letters 1997年第12期8卷 0-0,0-0页

作者： Hui Ying LI Kang Tai REN Ru Yu CHEN(institute of Elemento-Organic Chemistry, Nankai University, tianjin 300071) Inst. of Elemento-Organic Chemistry Nankai University Tianjin 300071 China

A series of novel phosphonoacetic acid derivatives, N-(ethoxycarbonylmethy-ethoxyphosphonyl)-α-amino acid esters and α-amino phosphonates, were synthesized via the reaction of the corresponding phosphonyl chloride with amino acid ester hydrochlorides or amino phosphonates in the presence of a base. The preliminary bioassay shows that some compounds show significant anti-viral activity against tobacco mosaic virus (TMV)

关键词： Novel Phosphonoacetic Acid Derivatives.Synthesis of N cm PN Amino Phosphonic Acid Esters and Their Bioactivities Ethoxycarbonylmethylphosphonyl Amino Esters and