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Testosterone therapy and mortality in US veterans

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Asian Journal of Andrology 2012年第5期14卷 667-668页

作者： bu B Yeap School of Medicine and Pharmacology University of Western Australia Perth WA 6160 Australia Department of Endocrinology and Diabetes Fremantle Hospital Fremantle WA 6160 Australia

Whether lower testosterone levels are a causal factor or biomarker for disease in older men remains fiercely debated, as randomized controlled trials with endpoints of cardiovascular events or mortality are lacking. Here, a recent retrospective study in US veterans is discussed, which compares mortality rates in men who were and were not prescribed testosterone.

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Small-signal Stability Criteria in Power Electronics-dominated Power Systems:A Comparative Review

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Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1003-1018页

作者： Qifan Chen Siqi bu Chi Yung Chung Department of Electrical and Electronic Engineer The Hong Kong Polytechnic UniversityHong KongChina Department of Electrical and Electronic Engineering Shenzhen Research InstituteCentre for Grid ModernisationInternational Centre of Urban Energy NexusCentre for Advances in Reliability and SafetyResearch Institute for Smart Energyand Policy Research Centre for Innovation and TechnologyThe Hong Kong Polytechnic UniversityHong KongChina

To tackle emerging power system small-signal stability problems such as wideband oscillations induced by the large-scale integration of renewable energy and power electronics,it is crucial to review and compare existing small-signal stability analysis *** this basis,guidance can be provided on determining suitable analysis methods to solve relevant small-signal stability problems in power electronics-dominated power systems(PEDPSs).Various mature methods have been developed to analyze the small-signal stability of PEDPSs,including eigenvalue-based methods,Routh stability criterion,Nyquist/Bode plot based methods,passivity-based methods,positive-net-damping method,lumped impedance-based methods,bifurcation-based methods,*** this paper,the application conditions,advantages,and limitations of these criteria in identifying oscillation frequencies and stability margins are reviewed and compared to reveal and explain connections and discrepancies among ***,efforts are devoted to mathematically proving the equivalence between these small-signal stability ***,the performance of these criteria is demonstrated and compared in a 4-machine 2-area power system with a wind farm and an IEEE 39-bus power system with 3 wind farms.

关键词： Impedance-based method oscillation analysis power electronic converter power electronics-dominated power system renewable power generation small-signal stability

Cohesion mechanisms for bioadhesives

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Bioactive Materials 2022年第7期7卷 105-118页

作者： Yazhong bu Abhay Pandit Institute of Medical Engineering Department of BiophysicsSchool of Basic Medical SciencesHealth Science CenterXi’an Jiaotong UniversityXi’an710061China CÚRAM SFI Research Centre for Medical Devices National University of IrelandGalwayIreland

Due to the nature of non-invasive wound closure,the ability to close different forms of leaks,and the potential to immobilize various devices,bioadhesives are altering clinical *** one of the vital factors,bioadhesives’strength is determined by adhesion and cohesion *** well as being essential for adhesion strength,the cohesion mechanism also influences their bulk functions and the way the adhesives can be *** there are many published reports on various adhesion mechanisms,cohesion mechanisms have rarely been *** this review,we have summarized the most used cohesion ***,the relationship of cohesion strategies and adhesion strategies has been discussed,including employing the same functional groups harnessed for adhesion,using combinational approaches,and exploiting different strategies for cohesion *** providing a comprehensive insight into cohesion strategies,the paper has been integrated to offer a roadmap to facilitate the commercialization of bioadhesives.

关键词： Bioadhesive Cohesion Hydrogel Medical device fixation Sealant

Selecting scale factor of Bayesian multi-fidelity surrogate by minimizing posterior variance

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Chinese Journal of Aeronautics 2022年第11期35卷 59-73页

作者： Hongyan bu Liming SONG Zhendong GUO Jun LI Institute of Turbomachinery School of Energy&Power EngineeringXi'an Jiaotong UniversityXi'an 710049China

The Bayesian Multi-Fidelity Surrogate(MFS)proposed by Kennedy and O’Hagan(KOH model)has been widely employed in engineering design,which builds the approximation by decomposing the high-fidelity function into a scaled low-fidelity model plus a discrepancy *** scale factor before the low-fidelity function,ρ,plays a crucial role in the KOH *** scale factor is always tuned by the Maximum Likelihood Estimation(MLE).However,recent studies reported that the MLE may sometimes result in MFS of bad *** this paper,we first present a detailed analysis of why MLE sometimes can lead to MFS of bad *** is because,the MLE overly emphasizes the variation of discrepancy function but ignores the function waviness when selectingρ.To address the above issue,we propose an alternative approach that choosesρby minimizing the posterior variance of the discrepancy *** tests on a one-dimensional function,two high-dimensional functions,and a turbine blade design problem,the proposed approach shows better accuracy than or comparable accuracy to MLE,and the proposed approach is more robust than ***,through a comparative test on the design optimization of a turbine endwall cooling layout,the advantage of the proposed approach is further validated.

关键词： Co-Kriging Gaussian process regression Multi-fidelity surrogate Optimization Scale factor

Holographic magnetized chiral density wave

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Chinese Physics C 2018年第11期42卷 85-92页

作者： Yanyan bu Shu Lin School of Physics and Astronomy Sun Yat-Sen UniversityZhuhai 519082China Department of Physics Harbin Institute of TechnologyHarbin 150001China

We explore the end point of the helical instability in a finite density, finite magnetic field background discussed by Kharzeev and Yee. The nonlinear solution is obtained and identified with the （magnetized） chiral density wave phase in the literature. We find there are two branches of solutions, which match the two unstable modes found before. At large chemical potential and magnetic field, the magnetized chiral density wave can be thermodynamically preferred over the chirally symmetric phase and chiral symmetry breaking phase. Interestingly, we find an exotic state with vanishing chemical potential at large magnetic field. We also attempt to clarify the role of anomalous charge in the holographic model.

关键词： chiral density wave holography axial anomaly

k-fold coloring of planar graphs

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Science China Mathematics 2010年第10期53卷 2791-2800页

作者： GuanFeng Ren YueHua bu Zhejiang Normal Univ Dept Math Jinhua 321004 Peoples R China

A k-fold n-coloring of G is a mapping φ: V (G) → Zk(n) where Zk(n) is the collection of all ksubsets of {1,2,...,n} such that φ(u) ∩φ(v) = φ if uv ∈ E(G).If G has a k-fold n-coloring,i.e.,G is k-fold *** the smallest integer n such that G is k-fold n-colorable be the k-th chromatic number,denoted by χk(G).In this paper,we show that any outerplanar graph is k-fold 2k-colorable or k-fold χk(C*)-colorable,where C* is a shortest odd cycle of ***,we investigate that every planar graph with odd girth at least 10k-9(k 3) can be k-fold (2k + 1)-colorable.

关键词： k-fold coloring planar graph the shortest odd cycle

Comments on Chinese guidelines for diagnosis and treatment of gastric cancer 2018(English edition)

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Chinese Journal of Cancer Research 2020年第4期32卷 446-447页

作者： Zhaode bu Jiafu Ji Key Laboratory of Carcinogenesis and Translational Research(Ministry of Education/Beijing) Center of Gastrointestinal SurgeryPeking University Cancer Hospital&InstituteBeijing 100142China

Gastric cancer remains one of the most important malignancies in the world,with more than 1,000,000 new cases and an estimated 783,000 deaths in 2018,making it the fifth most frequently diagnosed cancer and the third leading cause of cancer ***,most of these cases occurred in Asia,especially in China(1).Gastric cancer causes more than 200 billion CNY of direct and indirect economic losses in China *** the past decades,China has made great progress in the prevention and treatment of gastric cancer,but it is still a relatively prominent health problem,which has brought a huge burden to people's health and social economy.

关键词： diagnosis prevention treatment

A compact design of four-degree-of-freedom transmission electron microscope holder for quasi-four-dimensional characterization

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Science China(Technological Sciences) 2020年第7期63卷 1272-1279页

作者： ZHANG YiZhi bu YeQiang FANG XiaoYang WANG HongTao Center for X-Mechanics Zhejiang UniversityHangzhou 310027China Institute of Applied Mechanics Zhejiang UniversityHangzhou 310027China

Electron tomography(ET) has been demonstrated to be a powerful tool in addressing challenging problems, such as understanding 3 D interactions among various microstructures. Advancing ET to broader applications requires novel instrumentation design to break the bottlenecks both in theory and in practice. In this work, we built a compact four-degree-of-freedom(threedirectional positionings plus self-rotation) nano-manipulator dedicated to ET applications, which is called X-Nano transmission electron microscope(TEM) holder. All the movements of the four degrees of freedom are precisely driven by built-in piezoelectric actuators, minimizing the artefacts due to vibration and drifting of the TEM stage. Full 360° rotation is realized with an accuracy of 0.05° in the whole range, which solves the missing wedge problem. Meanwhile, the specimen can move to the rotation axis with an integrated 3D nano-manipulator, greatly reducing the effort in tracking sample locations during ***, in-situ stimulation function can be seamlessly integrated into the X-Nano TEM holder so that dynamic information can be uncovered. We expect that more delicate researches, such as those about 3D microstructural evolution, can be carried out extensively by means of this holder in the near future.

关键词： electron tomography in-situ transmission electron microscopy nano manipulation

Dual-frequency Discontinuous Space Vector Pulse Width Modulation for Five-phase Voltage Source Inverters with Harmonic Injection

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CSEE Journal of Power and Energy Systems 2021年第3期7卷 665-675页

作者： Tianyu Pu Feifei bu Haijun Xu Wenxin Huang school of Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China

This paper proposes a dual-frequency discontinuous space vector pulse width modulation(DFDSVPWM)for a five-phase voltage source inverter with harmonic *** this modulation,for dual-frequency voltage output and reduction of switching losses,two different zero-vector-inserted modes are flexibly employed by alternatively using two types of zero *** on the comparison with continuous SVPWM,the idea and principle of the proposed DFDSVPWM are analyzed and an example of PWM signals for one bridge is also *** switching losses analysis,the impact factors and the calculation method are investigated and the corresponding implementation is given as *** simulation and experimental results from a prototype verify the correctness and effectiveness of the proposed modulation and it has the advantages of outputting dual-frequency voltage and reducing switching losses.

关键词： Discontinuous space vector pulse width modulation dual frequency five-phase voltage source inver terharmonic injection switching losses