检索结果-南通市图书馆

Journal of Materials Science & Technology 2014年第8期30卷 736-742页

作者： Hansang Kwon marc Leparoux Akira Kawasaki Department of Materials System Engineering Pukyong National University365 Sinsenro608-759 BusanKorea Empa Swiss Federal Laboratories for Materials Science and TechnologyAdvanced Materials ProcessingFeuerwerkerstrasse 39CH-3602 ThunSwitzerland Department of Materials Processing Engineering Graduate School of EngineeringTohoku University980-8579 SendaiJapan

Functionally graded（FG） carbon nanotubes（CNT） and nano-silicon carbide（nSiC） reinforced aluminium（Al）matrix composites have been successfully fabricated using high-energy ball milling followed by solid-state spark plasma sintering *** CNTs were well-dispersed in the Al particles using the nSiC as a solid mixing *** different types of multi-walled CNTs were used to add different amounts of CNTs in the same *** ball milled Al—CNT—nSiC and Al—CNT powder mixtures were fully densified and demonstrated good adhesion with no serious microcracks and pores within an FG multilayer *** layer contained different amounts of the CNTs,and the nSiC additions showed different microstructures and *** is possible to control the characteristics of the FG multilayer composite through the efficient design of an Al—CNT—nSiC gradient *** concept offers a feasible approach for fabricating the dualnanoparticulate-reinforced Al matrix nanocomposites and can be applied to other scenarios such as polymer and ceramic systems.

关键词： Carbon nanotubes(CNT) Silicon carbide High-energy ball milling Spark plasma sintering(SPS) Functionally graded materials(FGM)

Alien calculus and non perturbative effectsin Quantum Field Theory

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2016年第6期11卷 31-34页

作者： marc P. Bellon Sorbonne Universites UPMC Univ Paris 06 UMR 7589 LPTHE 75005 Paris France CNRS UMR 7589 LPTHE 75005 Paris France

In many domains of physics, methods for dealing with non-perturbative aspects are required. Here, I want to argue that a good approach for this is to work on the Borel transforms of the quantities of interest, the singularities of which give non-perturbative contributions. These singularities in many cases can be largely determined by using the alien calculus developed by Jean Écalle. My main example will be the two point function of a massless theory given as a solution of a renormalization group equation.

关键词： Schwinger-Dyson equations series resommation alien calculus quantum field theory non Calculi Singularity SCHWINGER FUNCTIONAL EQUATIONS Calculus Foreigners

Wear Behavior of a Bio-inspired Bearing for off-center Loads

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2020年第6期17卷 1251-1262页

作者： Delphine Sysaykeo Jean-marc Linares Emmanuel Mermoz Alix-Marseile Universite CNRSCentre National de la Recherche ScientifiqueISMInstitut des Sciences du MouvementMarseille 13009France Advanced concepts and Dynamic systems architecture department Airbus HelicoptersAeroport International Marseille ProvenceMarignane 13700France

Misalignment is one of the most common causes of wear in bush *** improvements have been proposed by many ***,it did not efficiently reduce the *** geometrical designs sometimes reach their *** this reason,a bio-inspired design is proposed to solve the *** this article,a bio-inspired bearing suited to misalignment was tested and compared to a classical bush *** contact pressures of both bearings were compared with static Finite Element(FE)simulations for off-center *** to the complex shape of the involved contact,the performances of both bearings were also studied over *** wear behaviors were predicted with a numerical *** methodologies emplaced to simulate the wear were described in this ***,the wear coefficient determination obtained by experimental testing was *** pressure value,the contact zone and the wear depth were compared and *** wear results for the classical bearing are in accordance with the *** simulations show a deeper wear on the classical bush bearing than on the bio-inspired *** leads to a longer period of service life for the bio-inspired bearing.

关键词： biologically inspired design bush bearing wear simulation

When is a varicocele repair indicated： the dilemma of hypogonadism and erectile dysfunction？

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2016年第2期18卷 213-216,J0004页

作者： Ali A Dabaja marc Goldstein Department of Male Reproductive Medicine Weill Cornell Medical College New York USA Department of Urology Henry Ford Health System Detroit MI USA.

In the past, the indications for varicocelectomy are primarily for infertility with abnormal semen parameters, testicular hypotrophy/atrophy in adolescents, and/or pain. The surgical treatment of varicocele for hypogonadism is controversial and debated. Recently, multiple reports in the literature have suggested that varicocele is associated with hypogonadism and varicocele repair can increase testosterone levels. Men with hypogonadal symptoms should have at least two serum testosterone levels. Microsurgical varicocelectomy may be beneficial for men with clinically palpable varicoceles with documented hypogonadism. In this review, we summarize the most recent literature linking varicocele to hypogonadism and sexual dysfunction and the impact of repair on serum testosterone levels. We performed a search of the published English literature. The key words used were ＂varicocele and hypogonadism＂ and ＂varicocele surgery and testosterone.＂ We included published studies after 1998. We, also, evaluated the effect of surgery on the changes in the serum testosterone level regardless of the indication for the varicocele repair.

关键词： erectile dysfunction hypogonadism varicocele varicocelectomy

Microsurgical varicocelectomy： a review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2013年第1期15卷 56-60页

作者： Akanksha Mehta marc Goldstein Department of Urology and Center for Male Reproductive Medicine and Surgery Weill Cornell Medical College New York NY 10021 USA

Varicocelectomy is the most commonly performed surgical procedure for the treatment of male infertility. Although several different techniques for varicocele repair have been described in the literature, microsurgical varicocelectomy performed through a subinguinal or inguinal incision is recognized as the gold-standard approach for varicocelectomy, due to high success rates with minimal complications. Standard indications for varicocelectomy include palpable varicocele（s）, with one or more abnormal semen parameters, and, for the couple trying to conceive, in the setting of normal or correctable female infertility. However, varicocele repair is often recommended and undertaken for reasons other than infertility, including low serum testosterone, testicular pain, testicular hypotrophy and poor sperm DNA quality. This article reviews the technical aspects of microsurgical varicocelectomy, and its indications in adults and adolescents.

关键词： DNA fragmentation hypogonadism infertility microsurgical varicocelectomy orchalgia varicocele repair

Delineating the respective impacts of stochastic curl- and grad-forces in a family of idealized core genetic commitment circuits

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Electrical and Electronic Engineering in China 2016年第2期4卷 69-83页

作者： marc Turcotte Department of Mathematics The University of Texas at Arlington Arlington TX 76109 USA Biological Sciences The University of Texas at Dallas Richardson TX-75080 USA

Stochastic dynamics pervades gene regulation. Despite being random, the dynamics displays a kind of innate structure. In fact, two stochastic forces combine driving efforts： one force originates from the gradient of the underlying stochastic potential, and the other originates from the mathematical curl of the probability flux. The curl force gives rise to rotation. The gradient force gives rise to drift. Together they give rise to helical behavior. Here, it is shown that around and about the vicinity of attractive fixed points, the gradient force naturally wanes but the curl force is found to remain high. This leads to a locally noticeably different type of stochastic track near and about attractive fixed points, compared to tracks in regions where drift dominates. The consistency of this observation with the experimental fact that, in biology, fate commitment appears to not be a-priory locked-in, but rather necessitating active maintenance, is discussed. Hence attractive fixed-points are not only fuzzy, but may effectively be, locally, ＂more free＂.

关键词： systems biology theoretical biology gene regulation nonlinear dynamics stochasticity

Sperm function, mitochondrial activity and in vivo fertility are associated to their mitochondrial DNA content in pigs

在线全文

学校读者我要写书评

暂无评论

Journal of Animal Science and Biotechnology 2024年第4期15卷 1550-1558页

作者： marc Llavanera Yentel Mateo‑Otero Estel Vinolas‑Vergés Sergi Bonet marc Yeste Unit of Cell Biology Department of BiologyFaculty of SciencesUniversity of GironaGirona ES‑17003Spain Biotechnology of Animal and Human Reproduction(TechnoSperm) Institute of Food and Agricultural TechnologyUniversity of GironaGirona ES‑17003Spain Catalan Institution for Research and Advanced Studies(ICREA) Barcelona ES‑08010Spain

Background Despite their low abundance in sperm, mitochondria have diverse functions in this cell type, includ-ing energy production, signalling and calcium regulation. In humans, sperm mitochondrial DNA content(mtDNAc) has been reported to be negatively linked to sperm function and fertility. Yet, the association between mtDNAc and sperm function in livestock remains unexplored. For this reason, this study aimed to shed some light on the link between mtDNAc and sperm function and fertilising potential in pigs. A qPCR method for mtDNAc quantification was optimised for pig sperm, and the association of this parameter with sperm motility, kinematics, mitochondrial activity, and fertility was subsequently *** First, the q PCR method was found to be sensitive and efficient for mtDNAc quantification in pig sperm. By using this technique, mtDNAc was observed to be associated to sperm motility, mitochondrial activity and in vivo, but not in vitro, fertility outcomes. Specifically, sperm with low mtDNAc were seen to exhibit greater motility but decreased mitochondrial activity and intracellular reactive oxygen species. Interestingly, samples with lower mtD-NAc showed higher conception and farrowing rates, but similar in vitro fertilisation rates and embryo development, when compared to those with greater *** These findings enrich our comprehension of the association of mtDNAc with sperm biology, and lay the foundation for future research into employing this parameter as a molecular predictor for sperm function and fer-tility in livestock.

关键词： Fertility Mitochondria Motility mtDNA copy number qPCR Sperm

Joint Loading Estimation Method for Horse Forelimb High Jerk Locomotion:Jumping

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2019年第4期16卷 674-685页

作者： Joanne Becker Mermoz Emmanuel Linares Jean-marc Airbus Helicopters Aeroport de Marseille ProvenceMarignane 13700France Aix Marseille Univ CNRSISMInst Movement SciMarseille 13009France

Maximal local loads in animal joints are necessary to design bio-inspired mechanical *** studies presented methods to determine joint reaction forces in humans and ***,many of these methods are invasive,and no work has been published yet about the joint reaction forces in the horse forelimb during ***-invasive methods to measure the kinematics and ground reaction force of a horse forelimb were used in this work.A musculoskeletal model of horse forelimb was built with mechanical methods for the estimation of joint reaction *** entire forelimb was reconstructed by scanning real bones geometry with a 3D optical scanner and modeling all the muscles on a Computer Assisted Design(CAD)*** model dynamics were simulated with OpenSim in order to estimate the joint *** study allows knowing an order of magnitude of the loads at the joints at jumping in order to determine latter the maximal joint contact loading values that will be a key at designing bio-inspired joints for mechanical assemblies.

关键词： joint loading jumping kinematics modelling OpenSim

Phase coexistence properties of liquid mercury:a simulation study

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2006年第5期25卷 567-571页

作者： Jean-Louis Bretonnet Jean-marc Bomont Laboratoire de Physique des Milieux Denses Université Paul Verlaine1bd F.D.Arago57078 MetzCedex 3France

The thermophysical properties of expanded liquid mercury have been investigated along the liquid-vapor coexistence curve by using Monte Carlo and Molecular Dynamic simulations. For the purpose, an empirical state dependent interatomic potential for the region of dense metallic liquid is used, while the state dependence is not necessary near the cliffcal point. In order to test the validity of this potential, we determine the surface layering and the sound velocity, two properties very sensitive to the choice of the potential. Our results are in quite good agreement with other theoretical results and to the experimental data available in the literature.

关键词： mercury simulation phase coexistence liquid state

Growth and Photosynthesis Responses of a Super Dwarf Rice Genotype to Shade and Nitrogen Supply

在线全文

学校读者我要写书评

暂无评论

Rice science 2021年第2期28卷 178-190页

作者： marc SCHMIERER Oliver KNOPF Folkard ASCH Institute of Agricultural Sciences in the Tropics University of HohenheimStuttgart 70599Germany Institute for Bio-and Geo-Sciences IBG-2:Plant SciencesForschungszentrum Jülich GmbHJülich 52428Germany

Specific aspects of plant cultivation require tests under fully controlled environmentalconditions with restricted energy supply, such as orbit-based space laboratories and low-light *** these growing conditions, super dwarf plants have been developed as model crops, and a gibberellindeficientSuper Dwarf Rice genotype was proposed as a model crop for space flight plant *** tested this genotype in a climate chamber experiment under different illumination and nitrogen supplylevels to assess its suitability under scenarios with limited resource availability. A 25% reduction inillumination led to a 75% reduction in yield, mainly due to a 60% reduction in formed tillers and 20%reduction in grain weight, and a 80% reduction in illumination caused total yield loss. Leaf area underreduced illumination was significantly lower, and only marginal changes in the dimensions of leaves wereobserved. Plant photosynthesis was not significantly different between control and 75% illumination. Thiswas explained by a higher photochemical efficiency under lower light conditions and a reduced mesophyllresistance. Therefore, we concluded that this genotype is well-suited for plant experiments under spaceand light-limited conditions since it kept its small stature and showed no shade avoidance mechanisms,such as leaf elongation, which would complicate experiments under low-light conditions. Nitrogenconcentrations of 2.8 and 1.4 mmol/L led to no differences in plant growth. We concluded that a nitrogenconcentration of 1.4 mmol/L is sufficient for this genotype under the light intensities.

关键词： super dwarf rice photosynthetic limitation analysis shade nitrogen