3981   An improvement on the positivity results for 2-stage explicit RungeKutta methods An improvement on the positivity results for 2-stage explicit RungeKutta methods    2010 In this paper, we investigate the positivity property for a class of 2-stage explicit RungeKutta (RK2) methods of order two when applied to the numerical solution of special nonlinear initial value problems (IVPs) for ordinary differential equations (ODEs). We also pay particular attention to monotonicity property. We obtain new results for positivity which are important in practical applications. We provide some numerical examples to illustrate our results. © 2010 Elsevier B.V. All rights ... 查看全文

3982   Re-examination of the NDDO approximation and introduction of a new model beyond it Re-examination of the NDDO approximation and introduction of a new model beyond it    2003 The NDDO (neglect of diatomic differential overlap) approximation, a widely used basis for many semi-empirical molecular orbital (MO) approaches, is re-examined based on nonempirical frozen-core calculations on small molecules. An improvement going beyond the NDDO approximation is proposed. Our study shows that under the NDDO approximation, when the remaining non-DDO-type two-electron repulsion integrals (TERIs) are calculated using the basis set from the Lo¨wdin orthogonalization of the val... 查看全文

3983   An improved synthesis of 1,2,9,9a-tetrahydrocyclopropa[c]benz[e]indol-4-one (CBI): a simplified analog of the CC-1065 alkylation subunit An improved synthesis of 1,2,9,9a-tetrahydrocyclopropa[c]benz[e]indol-4-one (CBI): a simplified analog of the CC-1065 alkylation subunit Dale L. Boger, Weiya Yun, Bradley R. Teegarden    1992 查看全文

3984   New sets of solitary wave solutions to the KdV, mKdV, and the generalized KdV equations New sets of solitary wave solutions to the KdV, mKdV, and the generalized KdV equations    2008 In this work we introduce new schemes, each combines two hyperbolic functions, to study the KdV, mKdV, and the generalized KdV equations. It is shown that this class of equations gives conventional solitons and periodic solutions. We also show that the proposed schemes develop sets of entirely new solitary wave solutions in addition to the traditional solutions. The analysis can be used to a wide class of nonlinear evolutions equations. © 2006 Elsevier B.V. All rights reserved. 查看全文

3985   Derivation of structural characteristics of differential operator interpolating splines by the criteria of optimal control Derivation of structural characteristics of differential operator interpolating splines by the criteria of optimal control    2011 The optimal control theory is applied to investigate interpolating splines associated with arbitrary linear differential operators. The differential operator interpolating splines are considered a linear optimal control problem; the structure and the continuity property of differential operator interpolating splines are derived from the necessary conditions of the optimal control with constrained states. This method not only facilitates the derivation of the well-known structure and the continui... 查看全文

3986   GEOMETRIC APPROACH TO THE CONSTRUCTION OF THE BARRIER SURFACE IN DIFFERENTIAL GAMES. GEOMETRIC APPROACH TO THE CONSTRUCTION OF THE BARRIER SURFACE IN DIFFERENTIAL GAMES.    1987 In the present work we examine Isaacs' geometric method for the construction of the barrier surface in differential games. We are thus led, in a natural way, to a new (geometric) second-order necessary condition that a valid barrier surface must satisfy. This helps us, on the one hand, to clarify the appearance of a previously discovered qualitatively new type of barrier surface when the problem parameters enter a certain region of the parameter space, and, on the other hand, our systematic anal... 查看全文

3987   Membrane binding induces destabilization of cytochrome c structure Membrane binding induces destabilization of cytochrome c structure Arturo Muga, Henry H. Mantsch, Witold K. Surewicz    1991 查看全文

3988   Analysis of three-dimensional grids: Interpolating the nine-point prism. The shifting operator as an analytical instrument Analysis of three-dimensional grids: Interpolating the nine-point prism. The shifting operator as an analytical instrument    2007 A new equation for interpolating the nine-point prism by the circular or hyperbolic functions is illustrated. It is useful for estimating linear-term coefficients. New formulas for analytic and numerical differentiation and integration are obtained by the shifting operator. They are illustrated by examples. © 2006 Elsevier Inc. All rights reserved. 查看全文

3989   On the solution of the Abel equation of the second kind by the shifted Chebyshev polynomials On the solution of the Abel equation of the second kind by the shifted Chebyshev polynomials    2011 This paper presents a new approximate method of Abel differential equation. By using the shifted Chebyshev expansion of the unknown function, Abel differential equation is approximately transformed to a system of nonlinear equations for the unknown coefficients. A desired solution can be determined by solving the resulting nonlinear system. This method gives a simple and closed form. of approximate solution of Abel differential equation. The solution is calculated in the form. of a series with e... 查看全文

3990   Electron transfer reactions of high-potential iron-sulfur proteins and c-type cytochromes Electron transfer reactions of high-potential iron-sulfur proteins and c-type cytochromes Issac A. Mizrahi, Michael A. Cusanovich    1980 查看全文

3991   Parameters of a creasing-bending machine as applied to the scheme of transverse rotary shaping of chevron structures Parameters of a creasing-bending machine as applied to the scheme of transverse rotary shaping of chevron structures I. M. Zakirov;K. A. Alekseev    2007 Based on the topological representation and transformation of the elementary chevron structure module, we propose the dependences that relate the geometrical parameters of rollers with the chevron structure element sizes for the transverse scheme of rotary creasing and bending. The calculation scheme is realized in the form. of the parametrized geometrical model using CAD SolidWorks aids. 查看全文

3992   ON CONSTITUTIVE MODELLING AND INFORMATION FOR PHENOMENAL DISTRIBUTED PARAMETER CONTROL OF MULTICOMPONENT CHEMICAL PROCESSES IN FLUID- AND SOLIDPHASE. PART I. THE NEW PARTIAL DIFFERENTIAL CONSTITUTIVE ON CONSTITUTIVE MODELLING AND INFORMATION FOR PHENOMENAL DISTRIBUTED PARAMETER CONTROL OF MULTICOMPONENT CHEMICAL PROCESSES IN FLUID- AND SOLIDPHASE. PART I. THE NEW PARTIAL DIFFERENTIAL CONSTITUTIVE    1985 The problem under consideration is to find common physicochemical conditions of kinetics and phenomena of multicomponent chemical processes in fluid- and solidphase deciding the yield and quality of final products of these processes. The paper is devoted to the construction of a fundamental distributed parameter constitutive theory of physicochemical modelling of these chemical processes treated from the view of isotropic and anisotropic nonhomogeneous media with space and time memories. On the ... 查看全文

3993   Synthesis, Neutron Structure, and Reactivity of the Bis(dihydrogen) Complex RuH2(η2-H2)2(PCyp3)2 Stabilized by Two Tricyclopentylphosphines Synthesis, Neutron Structure, and Reactivity of the Bis(dihydrogen) Complex RuH2(η2-H2)2(PCyp3)2 Stabilized by Two Tricyclopentylphosphines Mary Grellier,† Laure Vendier,† Bruno Chaudret,† Alberto Albinati,‡ Silvia Rizzato,‡ Sax Mason,§ and    2005 Treatment of Ru(η4-C8H12)(η6-C8H10) with 3 bar H2 in the presence of 2 equiv of tricyclopentylphosphine (PCyp3) in pentane resulted in the isolation of the new bis(dihydrogen) complex RuH2(η2-H2)2(PCyp3)2 (2), characterized by NMR and single-crystal X-ray and neutron diffraction. The single-crystal neutron diffraction study is the first carried out for a bis(dihydrogen) complex. The coordination geometry around the metal center is a distorted octahedron defined by the two phosphines in a trans c 查看全文

3994   Asymmetric Conversion of Arenechromium Complexes to Functionalized Cyclohexenones:  Progress toward Defining an Optimum Chiral Auxiliary Asymmetric Conversion of Arenechromium Complexes to Functionalized Cyclohexenones:  Progress toward Defining an Optimum Chiral Auxiliary Anthony J. Pearson* and Alexander V. Gontcharov    1998 An investigation into the asymmetric synthesis of 5-substituted cyclohexenones via nucleophile addition to (alkoxyarene)chromium tricarbonyl complexes is described. Diastereoselectivity during the nucleophile addition step was achieved using alkoxy substituents derived from terpenoid substrates as chiral auxiliaries. Selectivities as high as 24:1 were obtained when 2-phenylisoborneol was used as the chiral auxiliary and as high as 17:1 using 3,3-(ethylenedioxy)isoborneol. The absolute stereochem... 查看全文

3995   Comparative Rates of Stream Purification under Natural and Controlled Conditions Comparative Rates of Stream Purification under Natural and Controlled Conditions H. W. Streeter    1930 查看全文

3996   In Calmodulin–IQ Domain Complexes, the Ca2+-Free and Ca2+-Bound Forms of the Calmodulin C-Lobe Direct the N-Lobe to Different Binding Sites In Calmodulin–IQ Domain Complexes, the Ca2+-Free and Ca2+-Bound Forms of the Calmodulin C-Lobe Direct the N-Lobe to Different Binding Sites D. J. Black and Anthony Persechini*    2011 We have investigated the roles played by the calmodulin (CaM) N- and C-lobes in establishing the conformations of CaM–IQ domain complexes in different Ca2+-free and Ca2+-bound states. Our results indicate a dominant role for the C-lobe in these complexes. When the C-lobe is Ca2+-free, it directs the N-lobe to a binding site within the IQ domain consensus sequence. It appears that the N-lobe must be Ca2+-free to interact productively with this site. When the C-lobe is Ca2+-bound, it directs the N 查看全文

3997   Total Synthesis of Bryostatin 7 via C–C Bond-Forming Hydrogenation Total Synthesis of Bryostatin 7 via C–C Bond-Forming Hydrogenation Yu Lu, Sang Kook Woo, and Michael J. Krische*    2011 The marine macrolide bryostatin 7 is prepared in 20 steps (longest linear sequence) and 36 total steps with five C–C bonds formed using hydrogenative methods. This approach represents the most concise synthesis of any bryostatin reported, to date. 查看全文

3998   Case study of integrated risk assessment mapping in the Southland Region of New Zealand Case study of integrated risk assessment mapping in the Southland Region of New Zealand    2000 Risk assessment at the regional level requires quality resource information on critical factors for sustainable land-use decisions. This paper describes a major community initiative underway in the Southland Region of New Zealand involving geographic information systems mapping of 850,000 ha at a 1:50,000 scale. At a southerly latitude of 46° in the southern part of the South Island of New Zealand, the critical factors affecting plant growth are soil quality and air temperature. Air temperat... 查看全文

3999   The Development of Automatic Welding Machine for Ring Crack The Development of Automatic Welding Machine for Ring Crack Song Jinhu    0 Developed an automatic girth welding machine for disinfection tank production, The machine has 2 sets of automatic welding equipment, Can completing two girths welding in the same time, Meeting the quality requirements. Welding machine control system for the control of the core as PLC, providing a variety of alternative welding mode and capacity of a large database of welding, so welding is adaptable, easy to operate. 查看全文

4000   Observer-based Reliable Control for Discrete Time Systems: An Average Dwell Time Approach Observer-based Reliable Control for Discrete Time Systems: An Average Dwell Time Approach Monika Marwaha and John Valasek    2012 This paper deals with the problem of reliable control for discrete time systems with actuator failures. The actuator is assumed to fail occasionally and can recover over a time interval. During the time of suffering failures, the considered closed-loop system is assumed unstable. Using an average dwell time method and under the condition that the activation time ratio between the system without actuator failures and the system with actuator failures is not less than a specified constant, an obse... 查看全文

4001   Efficiency and accuracy of numerical solutions to the time-dependent Schrödinger equation Efficiency and accuracy of numerical solutions to the time-dependent Schrödinger equation    2011 Recent significant improvements of the numerical solutions of the time-dependent Schro¨dinger equation beg the question as to whether these recent methods are comparable in efficacy (in terms of accuracy and computational time) to the current "method of choice," i.e., the Chebyshev expansion of the time-evolution operator and the fast-Fourier- transform. method of determining the kinetic energy. In this paper we review the methods in question and, by studying the time development of a cohere... 查看全文

4002   Zum Einstieg: Worum geht es? Zum Einstieg: Worum geht es? Joachim Hertzberg, Kai Lingemann;;reas Nüchter    0 Das zentrale Thema dieses Lehrbuchs sind Methoden und Algorithmen zur Steuerung mobiler Roboter. Roboter sind künstliche, von Menschen entworfene und gebaute technische Objekte. Was also liegt für Informatiker n?her als dieses Buch zu beginnen mit einer Reihe von Definitionen, welche die wesentlichen Begriffe kl?ren? 查看全文

4003   A Direct Route to Fluostatin C by a Fascinating Diels−Alder Reaction A Direct Route to Fluostatin C by a Fascinating Diels−Alder Reaction Maolin Yu† and Samuel J. Danishefsky*†‡    2008 The Diels?Alder reactions between vinylindenes (5 or 6) as the dienes with quinoneketals (7 or 8) or with methacrolein as the dienophiles were investigated. The remarkable regioselectivities of these Diels?Alder adducts suggested that the regiopreferences of these dienes and dienophiles in these cases are not a fixed property of each component of the cycloaddition but are mutually contigent. This paper shows how the Diels?Alder reaction between 6 and 8 was applied to the inaugural total synthese... 查看全文

4004   Synthesis and antitumor evaluation in mice of certain 7-deazapurine (pyrrolo[2,3-d]pyrimidine) and 3-deazapurine (imidazo[4,5-c]pyridine) nucleosides structurally related to sulfenosine, sulfinosine, Synthesis and antitumor evaluation in mice of certain 7-deazapurine (pyrrolo[2,3-d]pyrimidine) and 3-deazapurine (imidazo[4,5-c]pyridine) nucleosides structurally related to sulfenosine, sulfinosine, Kandasamy Ramasamy, Nobutaka Imamura, Naeem B. Hanna, Rick A. Finch, Thomas L. Avery, Roland K. Robi    1990 查看全文

4005   Enantioselective Total Syntheses of Slagenins A−C and Their Antipodes Enantioselective Total Syntheses of Slagenins A−C and Their Antipodes Biao Jiang,* Jia-Feng Liu, and Sheng-Yin Zhao    2003 Full details of the total syntheses of slagenins A?C (1a?c) and their antipodes (2a?c), novel bromopyrrole alkaloids with a unique tetrahydrofuro[2,3-d]imidazolidin-2-one moiety, are described in which their absolute stereochemistry was established. The key step in the syntheses involves the efficient condensation of dihydrofuran-3-one or glyoxal with urea to construct the slagenin bicycle core. 查看全文

4006   NEW DIFFERENTIAL FORMULATION OF RADIATIVE TRANSFER AND ITS APPLICATION TO THE ONE-DIMENSIONAL PROBLEM. NEW DIFFERENTIAL FORMULATION OF RADIATIVE TRANSFER AND ITS APPLICATION TO THE ONE-DIMENSIONAL PROBLEM.    1976 Radiation intensity in an absorbing-emitting medium is reformulated in a new differential form. The energy conservation equation for radiative transfer becomes an infinite-order partial differential equation. Multi-moment boundary conditions are introduced. Successive approximation techniques from physical consideration are then developed. Application of the present approximate method to the one-dimensional problem yields results in excellent agreement with existing numerical solutions. The meth... 查看全文

4007   New Zealand wool - from global commodity to differentiation New Zealand wool - from global commodity to differentiation    1997 New Zealand wool growers have launched a global marketing strategy. The R&D, technology and innovation has become a key part of this new marketing strategy. Sophisticated infrastructure of marketing and wool research capability aims to make consumer products out of New Zealand wool available in the pipeline of global industries. 查看全文

4008   NEW TECHNIQUES AND NEW INSTRUMENTATION IN THE THERMAL ANALYSIS OF PLASTICS. NEW TECHNIQUES AND NEW INSTRUMENTATION IN THE THERMAL ANALYSIS OF PLASTICS.    1979 Thermal analysis is now established as a primary tool in the characterization of plastics. With the development of microprocessor-controlled instrumentation, thermal analysis is entering a new phase. That is, a substantial increment in complexity of analysis is possible, yet the actual operation of the equipment is simpler, more automated, and more reliable than previously. This brief review is presented under headings: thermal analyzers (for thermal analysis, DTA, differential scanning calorime... 查看全文

4009   Proper Output Feedback H ∞  Control for Descriptor Systems: A Convex Optimization Approach Proper Output Feedback H ∞  Control for Descriptor Systems: A Convex Optimization Approach Lei Guo, Keyou Zhao;Chunbo Feng    0 In this paper, the H ∞  control problem is considered for linear descriptor systems by using convex optimization approaches. By giving sufficient and necessary conditions for the output feedback H ∞  control problem, feasible LMI-based design approaches are presented for both generalized and proper H ∞  controller. All proper H ∞  controllers are constructed via solutions of LMIs based on convex algorithms. These ... 查看全文

4010   New experimental results and improvement of the modelization of the (Ga,Mg) system New experimental results and improvement of the modelization of the (Ga,Mg) system    1991 Differential enthalpic analysis gave solidus and liquidus lines of the phase diagram. MgGa melts congruently; Mg2Ga is a stoichiometric compound; MgGa2 melts incongruently. The melting enthalpies of all the compounds were measured. A new numerical optimization of the thermodynamic properties was established using the NANCYUN program (Legendre polynomials), with all the known data. A consistent set of values in agreement with all the data (except one) is presented. 查看全文

上一页  [149]  [150]  [151]  [152]  [153]  [154]  [155]  [156]  [157]  [158]  [159]  [160]  [161]  [162]  [163]  [164]  [165]  [166]  [167]  [168]  [169]  [170]  [171]  [172]  [173]  [174]  [175]  [176]  [177]  [178]  [179]  [180]  [181]  [182]  [183]  [184]  [185]  [186]  [187]  [188]  [189]  [190]  [191]  [192]  [193]  [194]  [195]  [196]  [197]  [198]  [199]  [200]  [201]  [202]  [203]  [204]  [205]  [206]  [207]  [208]  [209]  [210]  [211]  [212]  [213]  [214]  [215]  [216]  [217]  [218]  [219]  [220]  [221]  [222]  [223]  [224]  [225]  [226]  [227]  [228]  [229]  [230]  [231]  [232]  [233]  [234]  [235]  [236]  [237]  [238]  [239]  [240]  [241]  [242]  [243]  [244]  [245]  [246]  [247]  [248]  [249]  [250]  [251]  [252]  [253]  [254]  [255]  [256]  [257]  [258]  [259]  [260]  [261]  [262]  [263]  [264]  [265]  [266]  [267]  [268]  [269]  [270]  [271]  [272]  [273]  [274]  [275]  [276]  [277]  [278]  [279]  [280]  [281]  [282]  [283]  [284]  [285]  [286]  [287]  [288]  [289]  [290]  [291]  [292]  [293]  [294]  [295]  [296]  [297]  [298]  [299]  [300]  [301]  [302]  [303]  [304]  [305]  [306]  [307]  [308]  [309]  [310]  [311]  [312]  [313]  [314]  [315]  [316]  [317]  [318]  [319]  [320]  [321]  [322]  [323]  [324]  [325]  [326]  [327]  [328]  [329]  [330]  [331]  [332]  [333]  [334]  [335]  [336]  [337]  [338]  [339]  [340]  [341]  [342]  [343]  [344]  [345]  [346]  [347]  [348]  [349]  [350]  [351]  [352]  [353]  [354]  [355]  [356]  [357]  [358]  [359]  [360]  [361]  [362]  [363]  [364]  [365]  [366]  [367]  [368]  [369]  [370]  [371]  [372]  [373]  [374]  [375]  [376]  [377]  [378]  [379]  [380]  [381]  [382]  [383]  [384]  [385]  [386]  [387]  [388]  [389]  [390]  [391]  [392]  [393]  [394]  [395]  [396]  [397]  [398]  399  [400]  [401]  [402]  [403]  [404]  [405]  [406]  [407]  [408]  [409]  [410]  [411]  [412]  [413]  [414]  [415]  [416]  [417]  [418]  [419]  [420]  [421]  [422]  [423]  [424]  [425]  [426]  [427]  [428]  [429]  [430]  [431]  [432]  [433]  [434]  [435]  [436]  [437]  [438]  [439]  [440]  [441]  [442]  [443]  [444]  [445]  [446]  [447]  [448]  [449]  [450]  [451]  [452]  [453]  [454]  [455]  [456]  [457]  [458]  [459]  [460]  [461]  [462]  [463]  [464]  [465]  [466]  [467]  [468]  [469]  [470]  [471]  [472]  [473]  [474]  [475]  [476]  [477]  [478]  [479]  [480]  [481]  [482]  [483]  [484]  [485]  [486]  [487]  [488]  [489]  [490]  [491]  [492]  [493]  [494]  [495]  [496]  [497]  [498]  [499]  [500]  [501]  [502]  [503]  [504]  [505]  [506]  [507]  [508]  [509]  [510]  [511]  [512]  [513]  [514]  [515]  [516]  [517]  [518]  [519]  [520]  [521]  [522]  [523]  [524]  [525]  [526]  [527]  [528]  [529]  [530]  [531]  [532]  [533]  [534]  [535]  [536]  [537]  [538]  [539]  [540]  [541]  [542]  [543]  [544]  [545]  [546]  [547]  [548]  [549]  [550]  [551]  [552]  [553]  [554]  [555]  [556]  [557]  [558]  [559]  [560]  [561]  [562]  [563]  [564]  [565]  [566]  [567]  [568]  [569]  [570]  [571]  [572]  [573]  [574]  [575]  [576]  [577]  [578]  [579]  [580]  [581]  [582]  [583]  [584]  [585]  [586]  [587]  [588]  [589]  [590]  [591]  [592]  [593]  [594]  [595]  [596]  [597]  [598]  [599]  [600]  [601]  [602]  [603]  [604]  [605]  [606]  [607]  [608]  [609]  [610]  [611]  [612]  [613]  [614]  [615]  [616]  [617]  [618]  [619]  [620]  [621]  [622]  [623]  [624]  [625]  [626]  [627]  [628]  [629]  [630]  [631]  [632]  [633]  [634]  [635]  [636]  [637]  [638]  [639]  [640]  [641]  [642]  [643]  [644]  [645]  [646]  [647]  [648]   下一页