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On continuum modeling using kinetic-frictional models in high shear granulation

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Particuology 2014年第2期12卷 124-127页

作者： P.J.Abrahamsson S.Sasic A.Rasmuson Department of Chemical Engineering Chalmers University of TechnologySE-412 96 GothenburgSweden Department of Applied Mechanics Division of Fluid DynamicsChalmers University of TechnologySE-412 96 GothenburgSweden

This short communication demonstrates why extreme caution has to be taken when applying conven- tional kinetic-frictional closures to continuum modeling of high shear granulation （HSG）, Conventional models refer to closure laws where the kinetic and frictional stresses are summed up to obtain the total stress field, In the simple, dense, and sheared system ofa Couette shear cell, the effect of the lack of scale separation on the model predictions is examined, both quantitatively and qualitatively. It is observed that the spatial resolution has a significant effect on the magnitude of the kinetic and frictional contributions to the solid phase stresses. With this new investigation and previous studies of HSG, it is concluded that conventional kinetic-frictional models are inadequate for continuum modeling of HSG.

关键词： Kinetic theory of granular flowFrictional stressSeparation of scalesHigh shear granulationCouette shear cell

OPTICAL SPECTRA OF LOW-DIMENSIONAL SEMICONDUCTORS

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红外与毫米波学报 2003年第6期22卷 401-405页

作者： Fu Y Chiragwandi Z Gthberg P Willander M Laboratory for Physical Electronics and Photonics Department of Physics and Engineering PhysicsChalmers University of TechnologyLaboratory for Physical Electronics and PhotonicsDepartment of Physics and Engineering PhysicsChalmers University of TechnologyLaboratory for Physical Electronics and PhotonicsDepartment of Physics and Engineering PhysicsChalmers University of TechnologyLaboratory for Physical Electronics and PhotonicsDepartment of Physics and Engineering PhysicsChalmers University of Technology S-412 96 GteborgSwedenS-412 96 GteborgSwedenS-412 96 GteborgSwedenS-412 96 GteborgSweden

We have studied the optical spectra of low-dimensional semiconductor systems by calculating all possible optical transitions between electronic states. Optical absorption and emission have been obtained under different carrier population conditions and in different photon wavelengths. The line-shapes of the peaks in the optical spectrum are determined by the density of electronic states of the system, and the symmetries and intensities of these peaks can be improved by reducing the dimensionality of the system. Optical gain requires in general a population inversion, whereas for a quantum-dot system, there exists a threshold value of the population inversion.

关键词：光谱低维半导体光学增益总体反转数值分析

Effect of Aging Treatment on Microstructural and Mechanical Characteristics of PEO Coatings on Mg-Al Alloy

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Journal of Materials Science & Technology 2008年第1期24卷 37-40页

作者： Y.L.Kim Department of Materials Engineering Korea Aerospace University Gyeonggi-do412-791Korea

Cast Mg-6 wt pct Al alloy solution-treated at 683 K for 16 h and aged at 498 K was coated by plasma electrolytic oxidation （PEO） *** Mg-6 wt pct Al alloy aged for 16 h exhibited the highest microhardness and wear *** PEO coating,however,the microhardness and wear resistance of coatings on Mg- 6 wt pct Al alloy showed a tendency to decrease with increasing aging time,which was in aggrement with the change of thickness with aging *** addition,the coatings on solution-treated Mg-6 wt pct Al alloy had better microhardness and wear resistance than those on aged Mg-6 wt pct Al ***,it can be understood that the aging treatment has a deleterious influence on the mechanical properties of coatings on Mg-6 wt pct Al alloy.

关键词： Cast Mg-6 wt pct Al Aging treatment Plasma electrolytic oxidation Thickness Microhardness Wear resistance

Integral formulas and the Ohsawa-Takegoshi extension theorem

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Science China Mathematics 2005年第Z1期48卷 61-73页

作者： Bo Berndtsson Department of Mathematics Chalmers University of Technology and the University of Goteborg S-412 96 GoteborgSweden

We construct a semiexplicit integral representation of the canonical solution to the (-δ)-equation with respect to a plurisubharmonic weight function in a pseudoconvex domain. The construction is based on a construction related to the Ohsawa-Takegoshi extension theorem combined with a method to construct weighted integral representations due to M. Andersson.

关键词： ■-equation integral representation

Conversing Rate from Morphine to Continuous Infusion of Fentanyl in Patients Suffering Cancer Pain

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Chinese Journal of Cancer Research 2007年第3期19卷 216-221页

作者：王文萍安达勇 The Affiliated Hospital Liaoning University of TCM Siduoka Cancer Center of Japan Siduoka 412-0028 Japan

Objective： To investigate the proper conversing rate from morphine to continuous infusion of fentanyl in patients suffering cancer pain. Methods： A retrospective study was carried on in 20 patients with cancer pain in Shizuoka Cancer Center from Sep. 2002 to Nov. 2003. Pain intensity, adverse reactions, and satisfaction index of patients were evaluated. Results： The pain intensity was stable in 17 patients indicating good pain-control within 1 week after conversion and unstable in 3 patients after conversion suggesting poor pain-control. Fentanyl injection could alleviate side effects and increase the satisfaction index of patients. Conclusion： The equipotent ratio for conversion of low dose morphine to fentanyl injection was established as 72：1, and for non low dose morphine a ratio less than 72：1 was proposed to get stable pain-relieving effect. But the equipotent ratio for conversion of morphine to continuous infusion of fentanyl could not be determined. We must consider the morphine dose before the confirmation of the conversing rate.

关键词： cancer pain morphine fentanyl administration clinical study

One photon-per-bit receiver using near-noiseless phase-sensitive amplification

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Light(Science & Applications) 2020年第1期9卷 543-549页

作者： Ravikiran Kakarla Jochen Schroder Peter A.Andrekson Photonics Laboratory Department of Microtechnology and Nanoscience(MC2)Chalmers University of Technology412-96 GothenburgSweden

Space communication for deep-space missions,inter-satellite data transfer and Earth monitoring requires high-speed data *** reach is fundamentally dictated by the available transmission power,the aperture size,and the receiver sensitivity.A transition from radio-frequency links to optical links is now seriously being considered,as this greatly reduces the channel loss caused by diffraction.A widely studied approach uses power-efficient formats along with nanowire-based photon-counting receivers cooled to a few Kelvins operating at speeds below 1 Gb/***,to achieve the multi-Gb/s data rates that will be required in the future,systems relying on pre-amplified receivers together with advanced signal generation and processing techniques from fibre communications are also *** sensitivity of such systems is largely determined by the noise figure(NF)of the pre-amplifier,which is theoretically 3 dB for almost all ***-sensitive optical amplifiers(PSAs)with their uniquely low NF of 0 dB promise to provide the best possible sensitivity for Gb/s-rate long-haul free-space ***,we demonstrate a novel approach using a PSA-based receiver in a free-space transmission experiment with an unprecedented bit-error-free,black-box sensitivity of 1 photon-per-information-bit(PPB)at an information rate of 10.5 Gb/*** system adopts a simple modulation format(quadrature-phase-shift keying,QPSK),standard digital signal processing for signal recovery and forward-error correction and is straightforwardly scalable to higher data rates.

关键词： receiver amplifier noise

A New Method with High Confidence for Validation of Computer Simulation Models of Flight Systems

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Journal of Systems Engineering and Electronics 1993年第4期4卷 43-52页

作者： Zhou XianminShanghai Research & Development Centre, 412 Guil in Road, Shanghai 200233, P.R.China Shanghai Research & Development Centre 412 Guil in Road Shanghai 200233 P.R. China

Computer simulation models may by used to gain further information about missile performance variability. Model validation is an important aspect of the test program for a missile system. Validation provides a basis for confidence in the model's results and is a necessary step if the model is to be used to draw inference about the behavior of the real missile. This paper is a review of methods useful for validation of computer simulation models of missile systems and provides a new method with high degree of confidence for validation of computer simulation models of missile systems. Some examples of the use of the new method in validating computer simulation models are given.

关键词： Model validation Model credibility Simulation modeling System simulation.

Determination of specific heat capacity by transient plane source

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Frontiers of Architectural Research 2013年第4期2卷 476-482页

作者： Axel Berne Bijan Adl-Zarrabi Carl-Eric Hagentoft Division of Building Technology Chulmers University of Technology Gothenburg SE-412 96 Sweden

A standard TPS measurement gives the thermal conductivity and thermal diffusivity of an isotropic material which in turn gives the heat capacity. The thermal properties of an anisotropic material can be measured if the heat capacity is known. A method for heat capacity measurement exists, where the TPS sensor is attached to a sample container which is surrounded by insulation. However, it＇s based on an assumption of negligible heat losses which leads to uncertainties in the results. From that position, this work aims to model the heat losses from the specific heat measurements with TPS. A new set-up is introduced, where the sensor with the container hangs freely in a steel tube to get more predictable heat losses. The results show that the measurements can be modelled as a network of lumps connected by conductances approximated as constant. Thereby, the conductances out from the system can be solved from a reference measurement and used as input for a model of a measurement with a sample. The model seems to underestimate the heat capacity, which might be a consequence of temperature dependent effects on the conductances from convection. The tube in the set-up could be evacuated to minimize those losses.

关键词： Specific heatcapacity Transient ptanesource TPS

An Analytical Method for Calculating P-SV Acoustical Field Excited by a Piezoelectric Strip with Finite Width and Thickness

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Chinese Physics Letters 2005年第11期22卷 2869-2872页

作者：张碧星汪承灏 Anders Bostroem Institute of Acoustics Chinese Academy of Sciences Beijing 100080 Department of Applied Mechanics Chalmers University of Technology SE-412 96 Goeteborg Sweden

A piezoelectric strip with finite width and thickness is placed on top of an isotropic elastic half-space. Acoustical field can be excited when a voltage is across the piezoelectric strip. An analytical method is presented to calculate the acoustical field by the dynamics characteristics of the piezoelectric strip. Considering the piezoelectric strip as an anisotropic material of the 6 mm-type crystal system, we study the two-dimensional P-SV acoustical fields inside the piezoelectric strip and the isotropic half-space. The displacement and stress distributions are analysed thoroughly. The effects of the width and thickness of the piezoelectric strip and other parameters on the acoustical field are also analysed.

关键词： An Analytical Method for Calculating P-SV Acoustical Field Excited by a Piezoelectric Strip with Finite