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Novel treatment options for perforations of the upper gastrointestinal tract:Endoscopic vacuum therapy and over-the-scope clips

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World Journal of Gastroenterology 2014年第24期20卷 7767-7776页

作者： rudolf Mennigen Norbert Senninger Mike G Laukoetter Department of General and Visceral Surgery University Hospital MuensterD-48149 MuensterGermany

Endoscopic management of leakages and perforations of the upper gastrointestinal tract has gained great importance as it avoids the morbidity and mortality of surgical *** the past years,covered selfexpanding metal stents were the mainstay of endoscopic ***,two new techniques are now available that enlarge the possibilities of defect closure:endoscopic vacuum therapy(EVT),and over-the-scope clip(OTSC).EVT is performed by mounting a polyurethane sponge on a gastric tube and placing it into the *** suction is applied via the tube resulting in effective drainage of the cavity and the induction of wound healing,comparable to the application of vacuum therapy in cutaneous *** system is changed every 3-5 *** overall success rate of EVT in the literature ranges from 84%to 100%,with a mean of 90%;only few complications have been *** are loaded on a transparent cap which is mounted on the tip of a standard *** bringing the edges of the perforation into the cap,by suction or by dedicated devices,such as anchor or twin grasper,the OTSC can be placed to close the *** acute endoscopy associated perforations,the mean success rate is 90%(range:70%-100%).For other types of perforations(postoperative,other chronic leaks and fistulas)success rates are somewhat lower(68%,and59%,respectively).Only few complications have been *** first reports are promising,further studies are needed to define the exact role of EVT and OTSC in treatment algorithms of upper gastrointestinal perforations.

关键词： Upper gastrointestinal Perforation Fistula Endoscopy Over-the-scope clip Endoscopic vacuum therapy

Collective effects for long bunches in dual harmonic RF systems

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Chinese Physics C 2008年第2期32卷 139-145页

作者：安世忠 Klaus Bongardt rudolf Maier 唐靖宇张天爵 China Institute of Atomic Energy Beijing 102413 China IKP FZ Juelich 52425 JuelichGermany Institute of High Energy Physics CAS Beijing 100049China

The storage of long bunches for large time intervals needs flattened stationary buckets with a large bucket height. Collective effects from the space charge and resistive impedance are studied by looking at the incoherent particle motion for the matched and mismatched bunches. Increasing the RF amplitude with particle number provides r.m.s wise matching for modest intensities. The incoherent motion of large amplitude particles depends on the details of the RF system. The resulting debunching process is a combination of the too small full RF acceptance together with the mismatch, enhanced by the collective effects. Irregular single particle motion is not associated with the coherent dipole instability. For the stationary phase space distribution of the Hofmann-Pedersen approach and for the dual harmonic RF system, stability limits are presented, which are too low if using realistic input distributions. For single and dual harmonic RF system with d=0.31, the tracking results are shown for intensities, by a factor of 3 above the threshold values. Small resistive impedances lead to coherent oscillations around the equilibrium phase value, as energy loss by resistive impedance is compensated by the energy gain of the RF system.

关键词： resistive impedance incoherent motion halo formation coherent dipole instability

Testicular volume and clinical correlates of hypothalamic–pituitary–testicular function:A cross-sectional study in obese men

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Asian Journal of Andrology 2020年第4期22卷 354-359页

作者： Mark Ng Tang Fui rudolf Hoermann Gary Wittert Mathis Grossmann Department of Medicine Austin Health University of MelbourneMelbourneVictoria 3084Australia Department of Endocrinology Austin HealthMelbourneVictoria 3084Australia School of Medicine University of AdelaideAdelaideSouth Australia 5005Australia

The aim of this study was to determine whether testicular volume is correlated with clinical and biochemical markers of hypothalamic–pituitary–testicular(HPT)axis *** was a cross-sectional substudy of a larger randomized controlled trial including obese men,body mass index(BMI)≥30 kg m−2,with a total testosterone level<12 nmol l−*** volume was measured by orchidometer,testosterone by liquid chromatography/tandem mass spectrometry,and body composition by dual-energy X-ray *** completed the Aging Males'Symptoms(AMS)score,International Index of Erectile Function-5(IIEF-5),physical function,and handgrip dynamometer ***-nine men participated with a median(interquartile range[IQR])age of 53.1(47.6,59.2)years,BMI of 37.0(34.6,40.5)kg m−2,and a total testosterone of 7.0(6.1,7.9)nmol l−*** testicular volume was 18(IQR:10,20)*** volume was negatively correlated with BMI(τ=−0.1952,P=0.010)and total fat mass(τ=−0.2115,P=0.005)independent of age and *** BMI,testosterone,sex hormone-binding globulin(SHBG),and luteinizing hormone(LH)were present in a multivariable model,only BMI(-0.38 ml change in testicular volume per 1 kg m-2BMI;95%CI:−0.74,−0.02;P=0.04)and LH(-0.92 ml change in testicular volume per 1 IU l-1 LH;95%CI:−1.75,−0.095;P=0.03)remained independent significant predictors of testicular *** volume was positively correlated with IIEF-5(τ=0.2092,P=0.021),but not related to handgrip strength,physical function tests,or *** obese men,testicular volume is inversely and independently associated with measures of adiposity,but not with most clinical or biochemical markers of HPT axis *** a clinical perspective,this suggests that obesity might compromise the reliability of reduced testicular volume as a sign of androgen deficiency in men.

关键词： hypothalamic-pituitary-gonadal axis testicular volume testosterone

Emittance-dominated long bunches in dual harmonic RF system

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Chinese Physics C 2008年第1期32卷 60-66页

作者：安世忠 Klaus Bongardt rudolf Maier 唐靖宇张天爵 China Institute of Atomic Energy IKP FZ Juelich 52425 JuelichGermany Institute of High Energy Physics CAS

The storage of long bunches for long time intervals needs flattened stationary buckets with a large bucket height. The longitudinal motion of the initially mismatched beam has been studied for both the single and dual harmonic RF systems. The RF amplitude is determined to be r.m.s wise matched. The bucket height of the single harmonic system is too small even for shorter bunch with only 20% increased energy spread. The Halo formation and even debunching can be seen after a few synchrotron periods for single particles with large amplitude. In the case of small energy spread for a cooled beam, Coulomb interaction cannot be ignored. The external voltage has to be increased to keep the r.m.s bunch length unchanged. The new voltage ratio R（N） simplifies physics for the emittance-dominated bunches with modest particle number N. For the single harmonic system, substantial amount of debunching occurs without increasing the external voltage, but very little if the RF amplitude is doubled. Results from the ORBIT tracking code are presented for the 1 GeV bunch in the HESR synchrotron, part of the GSI FAIR project.

关键词： bucket height mismatch space charge effect debunching

A composite micromotor driven by self-thermophoresis and Brownian rectification

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Chinese Physics B 2021年第11期30卷 107-111页

作者： Xin Lou Nan Yu Ke Chen Xin Zhou rudolf Podgornik Mingcheng Yang University of Chinese Academy of Sciences Beijing 100049China Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Institute for Advanced Study Shenzhen UniversityShenzhen 518060China Songshan Lake Materials Laboratory Dongguan 523808China Wenzhou Institute University of Chinese Academy of SciencesWenzhou 325001China

Brownian motors and self-phoretic microswimmers are two typical micromotors,for which thermal fluctuations play different *** motors utilize thermal noise to acquire unidirectional motion,while thermal fluctuations randomize the self-propulsion of self-phoretic *** we perform mesoscale simulations to study a composite micromotor composed of a self-thermophoretic Janus particle under a time-modulated external ratchet *** composite motor exhibits a unidirectional transport,whose direction can be reversed by tuning the modulation frequency of the external *** maximum transport capability is close to the superposition of the drift speed of the pure Brownian motor and the self-propelling speed of the pure self-thermophoretic ***,the hydrodynamic effect influences the orientation of the Janus particle in the ratched potential,hence also the performance of the composite *** work thus provides an enlightening attempt to actively exploit inevitable thermal fluctuations in the implementation of the self-phoretic microswimmers.

关键词： Brownian motors self-phoretic microswimmers thermal noise hydrodynamic effect

Diffusion of a chemically active colloidal particle in composite channels

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Chinese Physics B 2022年第4期31卷 436-440页

作者： Xin Lou Rui Liu Ke Chen Xin Zhou rudolf Podgornik Mingcheng Yang School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China Wenzhou Institute University of Chinese Academy of SciencesWenzhou 325001China

Diffusion of colloidal particles in microchannels has been extensively investigated,where the channel wall is either a no-slip or a slip-passive ***,in the context of active fluids,driving boundary walls are ubiquitous and are expected to have a substantial effect on the particle *** mesoscale simulations,we study the diffusion of a chemically active colloidal particle in composite channels,which are constructed by alternately arranging the no-slip and diffusio-osmotic boundary *** this case,the chemical reaction catalyzed by the active colloidal particle creates a local chemical gradient along the channel wall,which drives a diffusio-osmotic flow parallel to the *** show that the diffusio-osmotic flow can significantly change the spatial distribution and diffusion dynamics of the colloidal particle in the composite *** modulating the surface properties of the channel wall,we can achieve different patterns of colloidal position *** findings thus propose a novel possibility to manipulate colloidal diffusion in microfluidics,and highlight the importance of driving boundary walls in dynamics of colloidal particles in microchannels.

关键词： diffusion composite channels diffusio-osmotic flow hydrodynamic effect

Mathematical Modelling and Experimental Investigation of Gas Flow in Minichannels and Microchannels

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Journal of Thermal Science 2010年第4期19卷 289-294页

作者： Jan Vimmr Hynek Klterka Marek Hajzman Martin Luxa rudolf Dvork University of West Bohemia Faculty of Applied SciencesDepartment of MechanicsUniverzitni 22CZ-306 14 Pilsen Czech Republic University of West Bohemia Faculty of Mechanical EngineeringDepartment of Power System EngineeringUniverzitni 22CZ-306 14 PilsenCzech Republic Institute of Thermomechanics of Academy of Sciences of the Czech Republic Department of Fluid Dynamics Dolejskova 5CZ-182 00 PragueCzech Republic

The first part of this study is focused on the numerical modelling and experimental investigation of transonic flow through a 2D model of the male rotor-housing gap in a dry screw *** simulations of the clearance flow are performed with the help of the in-house compressible Navier-Stokes *** measurements based on the Schlieren method in Toepler configuration are carried *** objective of the second part of the study is to derive the analytical solution of gas microflow development in a gap between two parallel *** microflow is assumed to be laminar,incompressible and the velocity slip boundary conditions are considered at the *** constant velocity profile is prescribed at the *** the mathematical description of the problem,the Oseen equation is *** analytical results are compared with the numerical ones obtained using the developed incompressible Navier-Stokes solver including the slip flow boundary conditions.

关键词： clearance gap transonic flow compressible Navier-Stokes solver mieroflow development Oseen flow model analytical solution incompressible Navier-Stokes solver

Parametric study of spark plasma sintering of Al_(20)Cr_(20)Fe_(25)Ni_(25)Mn_(10) high entropy alloy with improved microhardness and corrosion

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International Journal of Minerals,Metallurgy and Materials 2022年第1期29卷 119-127页

作者： Andries Mthisi Nicholus Malatji A.Patricia I.Popoola L.rudolf Kanyane Department of Chemical Metallurgical and Materials EngineeringTshwane University of TechnologyP.M.B.X680PretoriaSouth Africa

Multicomponent Al_(20)Cr_(20)Fe_(25)Ni_(25)Mn_(10) alloys were synthesized using spark plasma sintering at different temperatures(800,900,and 1000℃)and holding times(4,8,and 12 min)to develop a high entropy alloy(HEA).The characteristics of spark plasma-synthesized(SPSed)alloys were experimentally explored through investigation of microstructures,microhardness,and corrosion using scanning electron microscopy coupled with energy dispersive spectroscopy(EDS),Vickers microhardness tester,and potentiodynamic polarization,*** diffraction(XRD)characterization was employed to identify the phases formed on the developed *** EDS results revealed that the alloys consisted of elements selected in this work irrespective of varying sintering *** XRD,EDS,and scanning electron microscopy collectively provided evidence that the fabricated alloys were characterized by globular microstructures exhibiting face-centered cubic phase,which was formed on a basis of solid solution *** finding implies that the SPSed alloy showed the features of *** alloy produced at 1000℃ and holding time of 12 min portrayed an optimal microhardness of HV 447.97,but the value decreased to HV 329.47 after heat *** same alloy showed an outstanding corrosion resistance *** increase in temperature resulted in an Al_(20)Cr_(20)Fe_(25)Ni_(25)Mn_(10) alloy with superior density,microhardness,and corrosion resistance over the other alloys developed at different parameters.

关键词： high entropy alloy spark plasma sintering microhardness corrosion

Microstructural evolution and delayed hydride cracking of FSW-AZ31 magnesium alloy during SSRT

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Transactions of Nonferrous Metals Society of China 2014年第10期24卷 3060-3069页

作者：曾荣昌 Wolfgang DIETZEL rudolf ZETTLER 甘为民孙芯芯山东科技大学材料科学与工程学院青岛266590 Institute of Materials Research Helmholtz-Zentrum Geesthacht

Evolution of microstructure including texture and fractography in a friction-stir welded（FSW） AZ31 magnesium alloy was investigated. The texture was measured using a neutron diffractometer. The microstructure and fractography of stress corrosion cracking（SCC） samples were observed by optical and scanning electron microscopy, respectively. An X-ray diffraction study was carried out on the fractured surfaces of the SCC specimens. The results indicated that a strong basal fiber was formed on the base material, whereas the grains in the stir zone were reoriented with their most basal planes tilted 25 o to the welding direction. Feather-like twins and hydride formed under slow strain rate tensile（SSRT） stress in air and aggressive solutions, respectively. Transgranular cracks propagated and finally failed on the retreating side in the solution. The hydride phase confirmed to sit on the fracture surface demonstrated the delayed hydride cracking（DHC） mechanism of the alloy.

关键词： magnesium alloys stress corrosion cracking friction stir welding texture microstructure