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EFFECT OF COOLING/LUBRICATION MEDIUM ON MACHINABILITY OF Ti6Al4V 被引量:5
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作者 戚宝运 何宁 李亮 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2011年第3期225-230,共6页
To better understand and know the roles of cooling/lubrication medium in the cutting process and expand their applicability,uncoated cemented carbide tools are used in high-speed turning Ti6Al4V.Dry,cold air,minimal q... To better understand and know the roles of cooling/lubrication medium in the cutting process and expand their applicability,uncoated cemented carbide tools are used in high-speed turning Ti6Al4V.Dry,cold air,minimal quantity lubrication(MQL),cryogenic MQL,and ionized air as the cooling/lubrication conditions are studied.Experimental results show that at speed 120 m/min turning Ti6Al4V,the cutting force under ionized air is smallest under all lubricant conditions,and tool life is best,next is cryogenic MQL.MQL and cold air almost have the same effect,a little better than dry.Meanwhile the smallest surface roughness is also obtained under ionized air condition.Flank wear and crater wear are the dominant failure modes when high-speed turning Ti6Al4V by SEM analysis.Finally the conclusion is drawn that ionized air and cryogenic MQL have better cooling/lubrication effects and can effectively improve the tool life. 展开更多
关键词 cooling/lubrication high-speed turning TI6AL4V minimal quantity lubrication(MQL) ionized air
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某车型前保险杠与翼子板V形间隙问题分析与改进
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作者 宋昌铭 吴华芝 苏世栋 《汽车与驾驶维修》 2022年第5期21-24,共4页
本文针对某车型前保险杠与翼子板V形间隙问题,在满足功能和低成本的要求下,对零件匹配方案进行改进优化,并进行实车验证。最终,解决车型前脸关键位置的匹配问题,车身质量得到提升,同时对于其他新项目车型出现类似结构问题具有一定的指... 本文针对某车型前保险杠与翼子板V形间隙问题,在满足功能和低成本的要求下,对零件匹配方案进行改进优化,并进行实车验证。最终,解决车型前脸关键位置的匹配问题,车身质量得到提升,同时对于其他新项目车型出现类似结构问题具有一定的指导作用。 展开更多
关键词 前保险杠 翼子板 V形间隙 匹配 离空量 前保险杠支架
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Common Fixed Point Theorems for Commuting Maps on a Complete Metric Space
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作者 朱顺荣 《Journal of Southeast University(English Edition)》 EI CAS 2001年第1期82-84,共3页
The concept of w distance on a metric space is introduced and three common fixed points theorems for commuting maps on a complete metric space are proved. These results extended fixed point theorems of Jungck a... The concept of w distance on a metric space is introduced and three common fixed points theorems for commuting maps on a complete metric space are proved. These results extended fixed point theorems of Jungck and Ciric. 展开更多
关键词 DISTANCE fixed point complete metric space
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Fixed points on complete metric spaces
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作者 朱顺荣 《Journal of Southeast University(English Edition)》 EI CAS 2004年第2期256-260,共5页
Two new fixed point theorems on two complete metric spaces are proved by using the concept of w -distance. One of the results is: let (X,d) and (Y,ρ) be two complete metric spaces,let p 1 be a w -distance o... Two new fixed point theorems on two complete metric spaces are proved by using the concept of w -distance. One of the results is: let (X,d) and (Y,ρ) be two complete metric spaces,let p 1 be a w -distance on X and p 2 be a w -distance on Y . If T is a continuous mapping of X into Y and S is a mapping of Y into X ,satisfying the inequalities: p 1(STx,STx′)≤c max {p 1(x,x′),p 1(x,STx),p 1(x′,STx′),p 1(x,STx′)/2,p 2(Tx,Tx′)} and p 2(TSy,TSy′)≤c max {p 2(y,y′),p 2(y,TSy),p 2(y′,TSy′),p 2(y,TSy′)/2,p 1(Sy,Sy′)} for all x,x′ in X and y,y′ in Y ,where 0≤ c<1. We have proved that ST has a unique fixed point z in X and TS has a unique fixed point w in Y . The two theorems have improved the fixed point theorems of Fisher and Namdeo,et al. 展开更多
关键词 fixed point complete metric space w-distance
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Spatial Object Aggregation Based on Data Structure, Local Triangulation and Hierarchical Analyzing Method
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作者 LIUYaolin MartienMolenaar 《Geo-Spatial Information Science》 2002年第1期44-54,共11页
This paper focuses on the methods and process of spatial aggregation based on semantic and geometric characteristics of spatial objects and relations among the objects with the help of spatial data structure (Formal D... This paper focuses on the methods and process of spatial aggregation based on semantic and geometric characteristics of spatial objects and relations among the objects with the help of spatial data structure (Formal Data Structure),the Local Constrained Delaunay Triangulations and semantic hierarchy.The adjacent relation among connected objects and unconnected objects has been studied through constrained triangle as elementary processing unit in aggregation operation.The hierarchical semantic analytical matrix is given for analyzing the similarity between objects types and between objects.Several different cases of aggregation have been presented in this paper. 展开更多
关键词 AGGREGATION spatial object HIERARCH data model
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Solutions and Conditional Lie-Backlund Symmetries of Quasi-linear Diffusion-Reaction Equations 被引量:1
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作者 ZUO Su-Li QU Chang-Zheng 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第1期6-12,共7页
New classes of exact solutions of the quasi-linear diffusion-reaction equations are obtained by seeking for the high-order conditional Lie-Baeklund symmetries of the considered equations. The method used here extends ... New classes of exact solutions of the quasi-linear diffusion-reaction equations are obtained by seeking for the high-order conditional Lie-Baeklund symmetries of the considered equations. The method used here extends the approaches of derivative-dependent functional separation of variables and the invariant subspace. Behavior to some solutions such as blow-up and quenching is also described. 展开更多
关键词 conditional Lie-Backlund symmetry exact solution quasi-linear diffusion-reaction equation
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Metrics on Noncompact Fuzzy Number Space E^n
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作者 冯玉瑚 《Journal of Donghua University(English Edition)》 EI CAS 2004年第2期83-87,共5页
The theory of metric spaces of fuzzy numbers has been established and found very convenient in many research fields on fuzzy analysis such as fuzzy integrals and differentials, fuzzy differential equations, fuzzy rand... The theory of metric spaces of fuzzy numbers has been established and found very convenient in many research fields on fuzzy analysis such as fuzzy integrals and differentials, fuzzy differential equations, fuzzy random variables and fuzzy stochastic processes etc.. But, a large part of this theory heavily depends on the condition that fuzzy number has to have compact support set and so fails to analyze and apply noncompact fuzzy numbers. The purpose of this paper is to introduce three classes of metrics on noncompact fuzzy number space and to discuss their basic properties, completeness and separability in detail. 展开更多
关键词 Noncompact fuzzy number METRIC COMPLETENESS SEPARABILITY ANALYSIS
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Bounded space algorithms for variant of variable-sized bin packing
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作者 李波 《Journal of Chongqing University》 CAS 2005年第3期164-169,共6页
Given a list of items and a sequence of variable-sized bins arriving one by one, it is NP-hard to pack the items into the bin list with a goal to minimize the total size of bins from the earliest one to the last used.... Given a list of items and a sequence of variable-sized bins arriving one by one, it is NP-hard to pack the items into the bin list with a goal to minimize the total size of bins from the earliest one to the last used. In this paper a set of approximation algorithms is presented for cases in which the ability to preview at most k(〉=2) arriving bins is given. With the essential assumption that all bin sizes are not less than the largest item size, analytical results show the asymptotic worst case ratios of all k-bounded space and offiine algorithms are 2. Based on experiments by applying algorithms to instances in which item sizes and bin sizes are drawn independently from the continuous uniform distribution respectively in the interval [0,u] and [u,l ], averagecase experimental results show that, with fixed k, algorithms with the Best Fit packing(closing) rule are statistically better than those with the First Fit packing(closing) rule. 展开更多
关键词 variable-sized bin packing bounded space algorithms offiine algorithms worst case performance average case performance
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Investigation of the Ion-Exchange Behavior of Zeolite Y in the Presence of Resin 被引量:2
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作者 Zhang Yi Zheng Jinyu +3 位作者 Liu Zhongqing Gao Xiuzhi Luo Yibin Zong Baoning 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2015年第2期50-56,共7页
Ion-exchange process of zeolite Y using ammonium-type resin as an exchange reagent was successfully carried out. The effect of temperature, space velocity and ion concentration on the breakthrough curves was carefully... Ion-exchange process of zeolite Y using ammonium-type resin as an exchange reagent was successfully carried out. The effect of temperature, space velocity and ion concentration on the breakthrough curves was carefully investigated. At the first exchange section, the maximum proportion of qualified zeolites(QR) was obtained at a temperature of 70 ℃, a weight hourly space velocity of 0.61 h-1, and an ion concentration of 197 mg/L. The minimum length of mass-transfer zone(MTZ) of the resin bed was achieved at a temperature of 70 ℃, a space velocity of 0.61 h-1, and an ion concentration of 423 mg/L. At the second exchange section, the length of MTZ of the resin bed was significantly increased, and the exchange of Na+ ions contained in zeolite Y was more difficult than that achieved at the first exchange section. In both the first and the second exchange sections, the zeolite Y subjected to ion exchange with the resin maintained the similar physical and chemical properties as compared to those exchanged by the conventional approaches, but the zeolite Y, which was obtained after ion exchange, contained a significantly lower content of Na2 O. 展开更多
关键词 zeolite Y RESIN ion-exchange
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The Discrete Horizontal Complex on Lattice Space
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作者 ZHOU Hui-qian LIU Zhen LI Qi-sheng 《Chinese Quarterly Journal of Mathematics》 CSCD 2009年第4期561-567,共7页
We define discrete total differential forms on lattice space by. changing coefficients of discrete differential forms from functions only of n to functions also of dependent variables un and their partial differences.... We define discrete total differential forms on lattice space by. changing coefficients of discrete differential forms from functions only of n to functions also of dependent variables un and their partial differences. And the discrete exterior derivative extends to be discrete total differential map which is also nilpotent. Then a discrete horizontal complex can be derived and be proved to be exact by constructing homotopy operators. 展开更多
关键词 discrete horizontal complex noncommutative differential calculus discrete higher Euler operator homotopy operator
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Thermo economic evaluation of oxy fuel combustion cycle in Kazeroon power plant considering enhanced oil recovery revenues 被引量:1
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作者 Ehsan Torabnejad Ramin Haghighi-Khoshkhoo Niloufar Sarabchi 《Journal of Central South University》 SCIE EI CAS 2014年第3期1025-1033,共9页
Oxy fuel combustion and conventional cycle(currently working cycle) in Kazeroon plant are modeled using commercial thermodynamic modeling software. Economic evaluation of the two models regarding the resources of tran... Oxy fuel combustion and conventional cycle(currently working cycle) in Kazeroon plant are modeled using commercial thermodynamic modeling software. Economic evaluation of the two models regarding the resources of transport and injection of carbon dioxide into oil fields at Gachsaran for enhanced oil recovery in the various oil price indices is conducted and indices net present value(NPV) and internal rate of return on investment(IRR) are calculated. The results of the two models reveal that gross efficiency of the oxy fuel cycle is more than reference cycle(62% compared to 49.03%), but the net efficiency is less(41.85% compared to 47.92%) because of the high-energy consumption of the components, particularly air separation unit(ASU) in the oxy fuel cycle. In this model, pure carbon dioxide with pressure of 20×105 Pa and purity of 96.84% was captured. NOX emissions also decrease by 4289.7 tons per year due to separation of nitrogen in ASU. In this model, none of the components of oxy fuel cycle is a major engineering challenge. With increasing oil price, economic justification of oxy fuel combustion model increases. With the price of oil at $ 80 per barrel in mind and $ 31 per ton fines for emissions of carbon dioxide in the atmosphere, IRR is the same for both models. 展开更多
关键词 oxy fuel combustion: C02 capture combined cycle enhanced oil recovery NOx reduction
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Space range estimate for battery-powered vertical take-off and landing aircraft 被引量:1
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作者 王波 侯中喜 +1 位作者 郭正 高显忠 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第9期3338-3346,共9页
A novel method for estimating the space range of battery-powered vertical take-off and landing(VTOL) aircraft is presented. The method is based on flight parameter optimization and numerical iteration. Subsystem model... A novel method for estimating the space range of battery-powered vertical take-off and landing(VTOL) aircraft is presented. The method is based on flight parameter optimization and numerical iteration. Subsystem models including required thrust, required power and battery discharge models are presented. The problem to be optimized is formulated, and then case study simulation is conducted using the established method for quantitative analysis. Simulation results show that the space range of battery-powered VTOL aircraft in a vertical plane is an oblate curve, which appears horizontally long but vertically short, and the peak point is not located on the vertical climb path. The method and results are confirmed by parameter analysis and validations. 展开更多
关键词 battery-powered aircraft vertical take-off and landing space range tailsitter
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Heavy Metals in Dust Deposition in the Vicinity of Coal Ash Disposal Site Divkovici Ⅱ
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作者 Abdel Dozic Vahida Selimbasic +3 位作者 Amira Cipurkovic Aida Crnkic Zorica Hodzic Ilvana Trumic 《Journal of Life Sciences》 2014年第5期461-472,共12页
DD (Dust deposition) was monitored over a 6-month period (April to September, 2011) at four sites located in villages near CADDⅡ(coal ash disposal site Divkovici Ⅱ), one inside recultivated CADDⅠ (coal ash d... DD (Dust deposition) was monitored over a 6-month period (April to September, 2011) at four sites located in villages near CADDⅡ(coal ash disposal site Divkovici Ⅱ), one inside recultivated CADDⅠ (coal ash disposal site Divkovici Ⅰ) and at one in the middle of forest barrier as control site. The main aim of this paper is to perform monitoring of air dust pollution in the area by measuring of dust deposition, different metals associated with it, and probable adverse effects on human health. Concentrations of metals were measured by using Perkin-Elmer model Inductively Coupled Plasma and statistically evaluated with SPSS 17.0 statistical program. There was a correlation between some metals (Mn, Mo and Pb) and DD distribution. The daily limit values for concentration of DD proposed by national "Regulations on air quality" (200 mg/m^2d average annual value and 350 mg/m^2d high value) exceed at three measuring sites. The average maximum content of DD was 684.8 mg/m^2d downwind of CADDII, and the average minimum was 46.8 mg/m^2d at measuring site F. Concentrations of pollutants hazardous to the environment as Ni, Cr, Cu, Mo, Mn and Pb vary from one site to another. 展开更多
关键词 Dust deposition coal ash disposal site heavy metals ENVIRONMENT power plant atmospheric pollution.
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Engineering oxygen vacancy on rutile TiO_2 for efficient electron-hole separation and high solar-driven photocatalytic hydrogen evolution 被引量:13
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作者 Fang Xiao1 Wei Zhou2 +5 位作者 Bojing Sun2 Haoze Li2 Panzhe Qiao2 Liping Ren2 Xiaojun Zhao1 Honggang Fu2 《Science China Materials》 SCIE EI CSCD 2018年第6期822-830,共9页
Oxygen vacancy(VO) plays a vital role in semiconductor photocatalysis. Rutile TiO2 nanomaterials with controllable contents of VO(0–2.18%) are fabricated via an insitu solid-state chemical reduction strategy, wit... Oxygen vacancy(VO) plays a vital role in semiconductor photocatalysis. Rutile TiO2 nanomaterials with controllable contents of VO(0–2.18%) are fabricated via an insitu solid-state chemical reduction strategy, with color from white to black. The bandgap of the resultant rutile TiO2 is reduced from 3.0 to 2.56 e V, indicating the enhanced visible light absorption. The resultant rutile TiO2 with optimal contents of VO(2.07%) exhibits a high solar-driven photocatalytic hydrogen production rate of 734 μmol h-1, which is about four times as high as that of the pristine one(185 μmol h-1). The presence of VOelevates the apparent Fermi level of rutile TiO2 and promotes the efficient electronhole separation obviously, which favor the escape of photogenerated electrons and prolong the life-time(7.6×103 ns) of photogenerated charge carriers, confirmed by scanning Kelvin probe microscopy, surface photovoltage spectroscopy and transient-state fluorescence. VO-mediated efficient photogenerated electron-hole separation strategy may provide new insight for fabricating other high-performance semiconductor oxide photocatalysts. 展开更多
关键词 oxygen vacancy rutile TiO2 surface engineering solar-driven photocatalysis hydrogen evolution
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On the Equi-nuclearity of Roe Algebras of Metric Spaces
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作者 Xiaoman CHEN Benyin FU Qin WANG 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2010年第4期519-528,共10页
The authors define the equi-nuclearity of uniform Roe algebras of a family of metric spaces. For a discrete metric space X with bounded geometry which is covered by a family of subspaces {Xi}i=1^∞, if {C^*(Xi)}i=1... The authors define the equi-nuclearity of uniform Roe algebras of a family of metric spaces. For a discrete metric space X with bounded geometry which is covered by a family of subspaces {Xi}i=1^∞, if {C^*(Xi)}i=1^∞ are equi-nuclear and under some proper gluing conditions, it is proved that C*(X) is nuclear. Furthermore, it is claimed that in general, the coarse Roe algebra C^* (X) is not nuclear. 展开更多
关键词 Nuclear C^*-algebra Uniform Roe algebra Equi-nuclear uniform Roe algebra
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Performance analysis of quantum key distribution based on air-water channel
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作者 周媛媛 周学军 《Optoelectronics Letters》 EI 2015年第2期149-152,共4页
Considering the air-water interface and ocean water’s optical attenuation,the performance of quantum key distribution(QKD)based on air-water channel is studied.The effects of photons’various incident angles to air-w... Considering the air-water interface and ocean water’s optical attenuation,the performance of quantum key distribution(QKD)based on air-water channel is studied.The effects of photons’various incident angles to air-water interface on quantum bit error rate(QBER)and the maximum secure transmission distance are analyzed.Taking the optical attenuation of ocean water into account,the performance bounds of QKD in different types of ocean water are discussed.The simulation results show that the maximum secure transmission distance of QKD gradually reduces as the incident angle from air to ocean water increases.In the clearest ocean water with the lowest attenuation,the maximum secure transmission distance of photons far exceeds the the working depth of underwater vehicles.In intermediate and murky ocean waters with higher attenuation,the secure transmission distance shortens,but the underwater vehicle can deploy other accessorial methods for QKD with perfect security.So the implementation of OKD between the satellite and the underwater vehicle is feasible. 展开更多
关键词 Air Bit error rate Electromagnetic wave attenuation OCEANOGRAPHY Optical communication Phase interfaces PHOTONS Vehicle transmissions VEHICLES
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Electrostatic Surface Waves on Semi-Bounded Quantum Electron-Hole Semiconductor Plasmas
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作者 Afshin Moradi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2017年第3期317-321,共5页
The electrostatic surface waves on semi-bounded quantum electron-hole semiconductor plasmas are studied within the framework of the quantum hydrodynamic model, including the electrons and holes quantum recoil effects,... The electrostatic surface waves on semi-bounded quantum electron-hole semiconductor plasmas are studied within the framework of the quantum hydrodynamic model, including the electrons and holes quantum recoil effects,quantum statistical pressures of the plasma species, as well as exchange and correlation effects. The dispersion characteristics of surface electrostatic oscillations are investigated by using the typical values of Ga As, Ga Sb and Ga N semiconductors. Numerical results show the existence of one low-frequency branch due to the mass difference between the electrons and holes in addition to one high-frequency branch due to charge-separation effects. 展开更多
关键词 electron-hole semiconductor plasma dispersion relation
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Time Operator in Relativistic Quantum Mechanics
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作者 Sina Khorasani 《Communications in Theoretical Physics》 SCIE CAS CSCD 2017年第7期35-38,共4页
It is first shown that the Dirac's equation in a relativistic frame could be modified to allow discrete time, in agreement to a recently published upper bound. Next, an exact self-adjoint 4 x 4 relativistic time oper... It is first shown that the Dirac's equation in a relativistic frame could be modified to allow discrete time, in agreement to a recently published upper bound. Next, an exact self-adjoint 4 x 4 relativistic time operator for spin-l/2 particles is found and the time eigenstates for the non-relativistic case are obtained and discussed. Results confirm the quantum mechanical speculation that particles can indeed occupy negative energy levels with vanishingly sma/l but non- zero probablity, contrary to the general expectation from classical physics. Hence, Wolfgang Pauli's objection regarding the existence of a self-adjoint time operator is fully resolved. It is shown that using the time operator, a bosonic field referred here to as energons may be created, whose number state representations in non-relativistic momentum space can be explicitly found. 展开更多
关键词 quantum mechanics special relativity foundations of quantum mechanics operator theory
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Fast vectorized distance matrix computation for multiple sequence alignment on multi-cores
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作者 Mohammed W. A1-Neama Naglaa M. Reda Fayed F. M. Ghaleb 《International Journal of Biomathematics》 2015年第6期243-257,共15页
Although high quality multiple sequence alignment is an essential task in bioinforma- tics, it becomes a big dilemma nowadays due to the gigantic explosion in the amount of molecular data. The most consuming time and ... Although high quality multiple sequence alignment is an essential task in bioinforma- tics, it becomes a big dilemma nowadays due to the gigantic explosion in the amount of molecular data. The most consuming time and space phase is the distance matrix computation. This paper addresses this issue by proposing a vectorized parallel method that accomplishes the huge number of similarity comparisons faster in less space. Per- formance tests on real biological datasets using core-iT show superior results in terms of time and space. 展开更多
关键词 BIOINFORMATICS multiple sequence alignment distance matrix parallel programming multi-cores.
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Bistability theorem in a cancer model
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作者 Jens Christian Larsen 《International Journal of Biomathematics》 SCIE 2018年第1期61-98,共38页
In this paper, I continue the study of the mathematical models presented in [J. C. Larsen, Models of cancer growth, J. Appl. Math. Comput. 53(1-2) (2015) 613-645] and [J. C. Larsen, The bistability theorem in a mo... In this paper, I continue the study of the mathematical models presented in [J. C. Larsen, Models of cancer growth, J. Appl. Math. Comput. 53(1-2) (2015) 613-645] and [J. C. Larsen, The bistability theorem in a model of metastatic cancer, to appear in Appl. Math.]. I shall prove the bistability theorem for the ODE model from [Larsen, 2015]. It is a mass action kinetic system in the variables C cancer, GF growth factor and GI growth inhibitor. This theorem says that for some values of the parameters, there exist two positive singular points c*+ = (C*+, GF*., GI*+), c*2- = (C*-, GF*, GI*-) of the vector field. Here C*- 〈 C*+ and e. is stable and c*+ is unstable, see Sec. 2. There is also a discrete model in [Larsen, 2015], it is a linear map (T) on three-dimensional Euclidean vector space with variables (C, GF, GI), where these variables have the same meaning as in the ODE model above. In [Larsen, 2015], I showed that one can sometimes find attine vector fields on three-dimensional Euclidean vector space whose time one map is T. I shall also show this in the present paper in a more general setting than in [Larsen, 2015]. This enables me to find an expression for the rate of change of cancer growth on the coordinate hyperplane C = 0 in Euclidean vector space. I also present an ODE model of cancer metastasis with variables C, CM, CF,GI, where C is primary cancer and CM is metastatic cancer and GF, GI are growth factors and growth inhibitors, respectively. 展开更多
关键词 IMMUNOLOGY CANCER CHEMOTHERAPY immune therapy discrete dynamicalsystem Gompertz function.
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