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New Formula for Geometric Stiffness Matrix Calculation

Journal of Applied Mathematics and Physics 2016年第4期4卷 733-748页

作者： I. Němec M. Trcala I. Ševčík H. Štekbauer Faculty of Civil Engineering Brno University of Technology Brno Czech Republic FEM Consulting S.R.O. Brno Czech Republic

The standard formula for geometric stiffness matrix calculation, which is convenient for most engineering applications, is seen to be unsatisfactory for large strains because of poor accuracy, low convergence rate, and stability. For very large compressions, the tangent stiffness in the direction of the compression can even become negative, which can be regarded as physical nonsense. So in many cases rubber materials exposed to great compression cannot be analyzed, or the analysis could lead to very poor convergence. Problems with the standard geometric stiffness matrix can even occur with a small strain in the case of plastic yielding, which eventuates even greater practical problems. The authors demonstrate that amore precisional approach would not lead to such strange and theoretically unjustified results. An improved formula that would eliminate the disadvantages mentioned above and leads to higher convergence rate and more robust computations is suggested in this paper. The new formula can be derived from the principle of virtual work using a modified Green-Lagrange strain tensor, or from equilibrium conditions where in the choice of a specific strain measure is not needed for the geometric stiffness derivation (which can also be used for derivation of geometric stiffness of a rigid truss member). The new formula has been verified in practice with many calculations and implemented in the RFEM and SCIA Engineer programs. The advantages of the new formula in comparison with the standard formula are shown using several examples.

关键词： Geometric Stiffness Stress Stiffness Initial Stress Stiffness Tangent Stiffness Matrix Finite Element Method Principle of Virtual Work Strain Measure

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Mixed hetero-/homogeneous TiO_(2)/N-hydroxyimide photocatalysis in visible-light-induced controllable benzylic oxidation by molecular oxygen

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Chinese Journal of Catalysis 2021年第10期42卷 1700-1711页

作者： Igor B.Krylov Elena R.Lopat'eva Irina R.Subbotina Gennady I.Nikishin Bing Yu Alexander O.Terent'ev N.D.zelinsky institute of organic chemistry of the russian academy of sciences moscow 119991russian federation Mendeleev university of chemical technology of russia moscow 125047russian federation Green catalysis center college of chemistryzhengzhou universityzhengzhou 450001henanchina

Homogeneous and heterogeneous types of catalysis are frequently considered as separate disciplines or even opposed to each *** the present work,a new type of mixed het-ero-/homogeneous catalysis was demonstrated for the case of selective alkylarene oxidation by molecular *** proposed catalytic system consists of two widely available components:N-hydroxyphthalimide(NHPI,a homogeneous organocatalyst for free-radical chain reactions)and nanosized TiO_(2)(heterogeneous UV-active photoredox catalyst).The interaction of NHPI with TiO_(2) allows for a shift from UV to visible light photoredox activity and generation of phthalimide-N-oxyl(PINO)radicals that diffuse into the solution where NHPI/PINO-catalyzed free-radical chain reaction can proceed without the additional light input providing a fundamental increase in energy *** NHPI/TiO_(2) ratio controls the selectivity of oxidation affording preferential formation of hydroperoxide or ketone from alkylarene.

关键词： TiO_(2) Photoredox catalysis N-hydroxyphthalimide N-oxyl radicals Aerobic oxidation

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The Long-Lived Photon Echo Response Locking Effect in the Presence of External Non-Resonant Laser Pulses with a Different Spatial Orientation

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Optics and Photonics Journal 2013年第7期3卷 360-363页

作者： Leonid A. Nefed’ev Elza I. Hakimzyanova Guzel I. Garnaeva Department of Educational Technologies in Physics Kazan Federal University Kazan Russia

The correlation of the inhomogeneous broadening of the resonance transition at different time intervals and the efficiency of long-lived photon echo response locking by the action of standing waves of non-resonant laser pulses are considered. It is shown that the long-lived photon echo response locking effect may be observed even at the angles of the relative orientation of the non-resonant standing wave laser pulses of less than one degree, due to the change in the correlation coefficient of inhomogeneous broadening at time intervals between the first and the second and after the third resonant laser pulses.

关键词： Photon Echo The Information Locking Spatial Non Uniform Electromagnetic Fields Relaxation Processes Time of The Response External Space-Non Uniform Non Resonant Laser Pulses

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南斯拉夫矿业(一)

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国外金属矿选矿 1988年第7期 1-12页

作者： B.Fidanev

前言根据中华人民共和国江西省政府和南斯拉夫马其顿共和国政府关于文化交流的协议,斯科普里矿业研究所的鲍里斯,菲丹塞夫(Boris Fidancev)和彼里、鲁斯夫(Petre Runcey)于1986年11月13日到1987年1月8日在江西冶金学院进行学术访问活动... 详细信息

前言根据中华人民共和国江西省政府和南斯拉夫马其顿共和国政府关于文化交流的协议,斯科普里矿业研究所的鲍里斯,菲丹塞夫(Boris Fidancev)和彼里、鲁斯夫(Petre Runcey)于1986年11月13日到1987年1月8日在江西冶金学院进行学术访问活动。 B、菲丹塞夫现任斯科普里矿业研究所选矿室主任,兼斯蒂普(Stip)地质矿业学院高级讲师。以前曾在矿山任经理。由于他具

关键词：矿石堆锌精矿沉砂铅锌混合精矿扫选尾矿选厂水力旋流器旋流分离器圆锥破碎机粗选南斯拉夫南欧浮选机选矿机械真空过滤机铅精矿混合浮选浮游选矿异丙基黄药优先浮选选择性浮选矿浆浓度给矿机铅锌矿床有色金属矿床矿业

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情仇生恨:著名神父正在杀人灭口

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知音：海外版 2000年第3期 40-41页

作者：伯克.,ev 丫头

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南斯拉夫矿业(三)

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国外金属矿选矿 1988年第9期 1-13页

作者： B.Fidan(?)ev

第二部分选矿厂设计中的几个问题在南斯拉夫,选矿厂投产以后,生产单位必须按每年产值的一定比例付给选厂设计单位。由于生产单位的经济效益直接与设计单位挂上钩,因此设计人员在设计阶段,特别注重经济效益。以下几个问题,是在参观了中... 详细信息

第二部分选矿厂设计中的几个问题在南斯拉夫,选矿厂投产以后,生产单位必须按每年产值的一定比例付给选厂设计单位。由于生产单位的经济效益直接与设计单位挂上钩,因此设计人员在设计阶段,特别注重经济效益。以下几个问题,是在参观了中国五个选矿厂,通过与南斯拉夫以及欧美一些国家的选矿厂相比较以后归纳出来的。

关键词：浮选机铅锌矿选矿机械矿石性质选厂南斯拉夫南欧混合精矿混合矿闪速浮选铅锌精矿选矿厂设计旋流器矿浆分离浮选混合浮选浮游选矿磨矿机磨机皮带给矿机粗选排矿粒度筑坝坝施工设备运转率

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爱丽丝梦境

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花样盛年 2014年第7期 42-47页

作者：李斯洁 ev视觉

斑斓夏日，畅游在繁茂的丛林中，仿佛置身于爱丽丝的梦境里，充满了童话般的浪漫与美好。

关键词：模特着装服装搭配时尚潮流

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Delivery on Scarred Uterus at Souro Sanou Teaching Hospital, Burkina Faso (about 531 Cases)

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Open Journal of Obstetrics and Gynecology 2022年第9期12卷 927-933页

作者： Yaméogo Rélwendé Barnabé Kaboré Ahmed Komboigo Béwendin evélyne Somé Der Adolphe Bambara Moussa Obstetrics-Gynecology and Reproductive Medicine Department Souro Sanou Teaching Hospital Bobo Dioulasso Burkina Faso Public Health Department Joseph Ki-Zerbo University Ouagadougou Burkina Faso

Introduction: Therapeutic conduct for delivery via a scarred uterus is controversial in modern obstetrics. Some authors recommend a ceasarean section. The purpose of this study was to analyse the conduct and prognosis of delivery via scarred uterus at Souro Sanou Teaching Hospital in Bobo-Dioulasso. Methods: We conducted a descriptive cross-sectional study from January 1 to December 31, 2017. Data were collected from medical, birth, and operating room records. Result: In total, 531 scared uterus deliveries and 5293 deliveries have been recorded in our study;the frequency of deliveries via a scarred uterus was 9.96%. The average age of the patients was 28.02 years old, with extremes of 17 and 44 years. The average parity was 2.34, with extremes of 1 and 8. Patients with a spacing interval between births of at least 24 months accounted for 86.6% of observed patients. Patients with a single scar uterus made up 70.6% of the population. There were 349 (65.73%) patients who had an emergency caesarean section during a previous delivery. The trial of vaginal delivery via a scarred uterus was conducted on 182 patients with a success rate of 89.56%. There was no maternal death. However, we noted 23 foetal deaths (4.33%). Conclusion: More than 50% of parturient women with a single caesarean uterine scar who underwent the uterine test gave birth vaginally in our department. However, like most previous studies on the subject, we recommend vaginal delivery in the presence of a prior caesarean-scarred uterus whenever possible.

关键词： Scarred Uterus Delivery Bobo Dioulasso

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Study of Caspian Goby Neogobius sp. Karyotype Flexibility from Several Biotops

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Journal of Life Sciences 2014年第5期8卷 442-446页

作者： Aithazha Bigaliev Saidina Kobegenova Viktor Vasil'ev Elena Vasil'eva Aiman Imentai Ashan Shametov Department of Molecular Biology and Genetics Al-Farabi Kazakh National University Almaty BOX 050040 Kazakhstan IPEE (Institute of Ecology and evolution) Russian Academy of Sciences Russia Zoological Museum Moscow State University Moscow Russia

The karyotype of Caspian goby was studied, which has been identified as Caspian bighead goby-Neogobius gorlap before. The results of cytogenetic analyses have shown that the diploid set of goby varies from 38 to 40 chromosomes, which is different from bighead goby （2n = 43-46）. We assumed that Caspian goby has independence as a species.

关键词： Caspian goby diploid number of chromosomes karyotype cytogenetic chromosomal mutation evolution.

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黑胡椒营养缺乏症的诊断

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热带作物科技 1990年第4期 78-81页

作者： Nybe.,ev 黄昭

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