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Features of Boiling on an Artificial Surface—Bubble Formation, Wall Temperature Fluctuation and Nucleation Site Interaction

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Journal of Thermal Science 2002年第3期11卷 226-234页

作者： m.Shoji R.mosdorf L.Zhang Y.Takagi K.Yasui m.yokota Department of mechanical Engineering The University of Tokyo Tokyo Japan Faculty of Computer Science Bialystok University of Technology ul. Wiejska Poland

The artificial surfaces are applied to study the pool boiling features, including the bubble behaviors, the surface temperature fluctuation, the heat transfer characteristics and nucleate site interaction. Three sets of experiments are carried out to investigate the influences of cavity shape, cavity size, cavity spacing on the boiling phenomena. Experimental results reveal that bubbling from the cylindrical as well as reentrant cavity is generally stable. The influence of cavity diameter on the bubble behaviors and the temperature fluctuation seems very weak while the effect of cavity depth cannot be neglected. As for the two cavity conditions, the bubble behaviors show the different features depending on the dimensionless cavity spacing. Three significant factors (thermal interaction, hydraulic interaction, bubble coalescence) control the nucleation site interaction, and the competition and dominance of the factors yield four interaction regimes.

关键词： pool boiling artificial surface boiling chaos nucleation site interaction.

Endovascular Irradiation Prevents Sm ooth muscle CellPro-liferation and Neointim alHyperplasia in Rabbits

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Journal of Huazhong University of Science and Technology(medical Sciences) 1999年第3期19卷 240-245页

作者： XU Linfeng 1, WU Yudan 2, FENG Gansheng 1 1 Department of Radiology, Xiehe Hospital, Tongji medical University, Wuhan 430030 2Institute of Hematology, Xiehe Hospital, Tongji medical University, Wuhan 430030 Oguchi m, yokota H, Nakagawa T, Yam Department of Radiology Xiehe Hospital Tongji Medical University Wuhan Institute of Hematology Xiehe Hospital Tongji Medical University Wuhan Department of Radiology Kanazawa Medical University Japan

The present study examined the temporal responses and the efficacy of 192Ir HDR endovascular irradiation for preventing smooth muscle cell proliferation of rabbit iliac arteries after PTA with a cutting balloon catheter. Endovascular irradiation with 12 Gy was randomly performed on the one side of iliac arterial segment with the unirradiated side serving as a control. Animals were euthanatized 1, 2, 3, 4, 8 and 12 week(s) after angioplasty. Histopathological and immunohistochemical studies were carried out. Histopathology showed repair of the dissection by cellular accumulation and a striking reduction in the amount of neointimal hyperplasia in the irradiated arteries as compared with control vessels. A peak of PCNA positive ratio was in neointima of the control arterial segments at a week. 2 - 4 weeks after irradiation, the neointimal PCNA positive ratio was still significantly increased in the control arterial segments compared with the irradiated arterial segments. After 8 weeks, PCNA positive ratio was below 1 % in both irradiated arterial segments and the control. Our results showed that the 192Ir HDR afterloading irradiation with a dose of 12 Gy can be considered sufficient for inhibiting neointimal hyperplasia in angioplastized rabbit iliac arteries with cutting balloon catheter.

关键词： neointimal hyperplasia endovascular irradiation PCNA

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控制树脂基复合材料固化过程的方法

导弹与航天运载技术 1981年第2期 70-77页

作者： m.J.yokota 华宝家

本文评述了在石墨纤维/热熔化环氧无纬布固化过程中根据工艺参数(如加压时的温度及加热速度)对介电粘度进行控制的所谓“介电粘度监控技术”。在固化过程中控制粘度,对于获得性能良好的层压板固然需要,但这还不够。除了要了解粘度状态... 详细信息

本文评述了在石墨纤维/热熔化环氧无纬布固化过程中根据工艺参数(如加压时的温度及加热速度)对介电粘度进行控制的所谓“介电粘度监控技术”。在固化过程中控制粘度,对于获得性能良好的层压板固然需要,但这还不够。除了要了解粘度状态及开始胶化方面的情况外,同时还需要确定挥发物完全逸出之点,测定此次要关键点,对于固化热熔化环氧如AS/3501-5是很重要的。现在很清楚,测定树脂挥发物全部逸出而同时又具有足够流动性的时间-溫度区间是获得热固性树脂完好固化的关键。热压罐压力必须在这个关键的时间-溫度区间内施加,才能获得具有恰当的树脂/纤维比例而又无气孔的层压板。

关键词：树脂基复合材料粘度孔隙挥发物逸出粘滞度流动特性铸件缺陷挥发分无纬布短梁剪切固化过程层压板塑料板材热压罐热固性树脂

Influence of cerium ions on structure-dependent magnetic properties of Ba-Sr m-type hexaferrite nanocrystals

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Journal of Rare Earths 2024年第2期42卷 364-372,I0005页

作者： Ram A.Pawar Sunil m.Patange P.m.Dighe Sher Singh meena Abdullah GAl-Sehemi mehboobali Pannipara Santosh S.Jadhav Department of Physics ArtsCommerce and Science CollegeAhmednagar413711MaharashtraIndia Department of Physics Shri Krishna MahavidyalayaGunjotiDistOsmanabad413606MaharashtraIndia Padmashri Vikhe Patil College of Arts Science and CommercePravaranagarA/P.Loni(Kd)Tal.RahataDistAhmednagar413713MaharashtraIndia Solid State Physics Division Bhabha Atomic Research CentreMumbai400085MaharashtraIndia Department of Chemistry King Khalid UniversityAbha61413Saudi Arabia Department of Physics D.S.M's ArtsCommerce and Science CollegeJintur431509MaharashtraIndia

The present study is a systematic effort to investigate the structure-sensitive magnetic parameters of Ce^(3+) substituted Ba-Sr hexaferrite nanocrystals chemically formulated as Ba_(0.5)Sr_(0.5)Ce_(x)Fe_(12-x)O_(19) where x=0.0-0.2 with Δx=*** hexaferrite powders were prepared using the sol-gel self-ignition route and structurally characterized by means of powder X-ray diffraction and Fourier transform infrared *** creation of the m-type hexaferrite phase within the synthesized samples was revealed from the Rietveld refinement of the X-ray *** occurrence of a secondary phase of CeO_(2) was revealed within the hexaferrites for the substitution,x> *** refined X-ray diffraction data were utilized to compute the lattice parameters,X-ray density,and lattice parameter *** crystal structure plotted from the refined XRD data reveals the occupancy of the ions at different lattice *** XPS data of the hexaferrite were analyzed to confirm the oxidation states of the constituent *** nanocrystalline nature of the hexaferrites was revealed from the crystallite sizes calculated using Scherer's *** analysis of FTIR spectra confirms that only a fraction of Ce^(3+)accommodated in the lattice and the remaining Ce content reside in the form of the CeO_(2) *** morphology of the hexaferrites was analyzed from the FESEm profiles of the ferrite *** magnetic behavior study was performed by analyzing the Curie temperature,hysteresis loops,and hyperfine interactions by means of susceptibility,V.S.m,and mossbauer spectroscopy,*** hexaferrites with increasing coercivity,decreasing saturation magnetization,and decreasing Curie temperature are reported in the *** substituted Ce^(3+)ions inhibit the grain growth and create lattice imperfections giving rise to hexaferrites with tuned magnetic parameters suitable for different applications.

关键词： Ba-Sr hexaferrite Ce^(3+)substitution XPS Saturation magnetization Coercivity m?ssbauer spectroscopy

Frequency-dependent viscoelasticity effects on the wave attenuation performance of multi-layered periodic foundations

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 407-424页

作者： m.SAFI m.VAKILIFARD m.J.mAHmOODI Faculty of Civil Water&Environmental EngineeringShahid Beheshti UniversityTehran ***Iran Faculty of mechanical and Energy Engineering Shahid Beheshti UniversityTehran ***Iran

In this paper,layered periodic foundations(LPFs)are numerically examined for their responses to longitudinal and transverse modes in the time and frequency *** different unit-cells,i.e.,2-layer,4-layer,and 6-layer unit-cells,comprising concrete/rubber,concrete/rubber/steel/rubber,and concrete/rubber/steel/rubber/lead/rubber materials,respectively,are taken into ***,the viscoelasticity behavior of the rubber is modeled with two factors,i.e.,a frequency-independent(FI)loss factor and a linear frequency-dependent(FD)loss *** the extraction of the complex dispersion curves and the identification of the band gaps(BGs),the simulations of wave transmission in the time and frequency domains are performed using the COmSOL *** parametric studies evaluate the effects of the rubber viscoelasticity models on the dispersion curves and the wave transmission for the longitudinal and transverse *** results show that considering the rubber viscoelasticity enhances the wave attenuation ***,the transverse-mode damping is more sensitive to the viscoelasticity model than its longitudinal *** 6-layer unit-cell LPF exhibits the lowest BG,ranging from 4.8 Hz to 6.5 Hz.

关键词： layered metamaterial periodic foundation complex dispersion curve wave transmission diagram

Engineering of efficient visible light photocatalysts:Ti_(1-x+y)Cu_(x)La_(y)O_(2)(x=0.03;y=0,0.005,0.01) compositions

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Journal of Rare Earths 2024年第3期42卷 497-505,I0003页

作者： S.m.Yakout A.m.Youssef Inorganic Chemistry Department National Research Centre(NRC)El Buhouth StDokkiCairo12622Egypt

In dye-photocatalysis, widening the wavelengths absorption range of catalysts as well as aborting the recombination of the photoexcited charge carriers(electrons-holes pairs) are of paramount *** the current study, we report the photocatalytic characteristics of four compositions composed of TiO_(2),Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders for two harmful dyes(Congo red and methylene blue). The X-ray diffraction technique verified the configuration of mixed anatase and rutile phases in pure TiO_(2)and Ti_(0.97)Cu_(0.03)O_(2)powders while Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders possess anatase phase only. The changes of the band gap structure and dimensions of the unit cell volume of TiO_(2)confirm the substitution of Ti^(4+)sites by Cu^(2+)and La^(3+)ions. Remarkable widening of wavelengths absorption with formation of long absorption tails were found in TiO_(2)(3.13 e V) through insertion of La^(3+)plus Cu^(2+)ions. Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)samples exhibit a visible light band gap of 2.3 and 2.7 e V, respectively. Based on SEm images, incorporation of Cu^(2+)and La^(3+)ions influences the surface morphology of TiO_(2). The resulting Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders present enhanced photocatalytic activity towards Congo red dye degradation compared to pure one under natural solar spectrum. The best Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst exhibits superior photocatalytic activity of 96% for 10 ppm CR dye in 20 min as well as above average photocatalytic efficiency of 63% for 30 ppm CR dye in 120 min. As well, it showed acceptable photodegradation activity of 52% for 30 ppm mB solution in 140 min of sunlight irradiation. The heightened photodegradation efficiency of Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst can be clarified in terms of higher ch

关键词： Semiconductor TiO_(2) Rare earths Congo red methylene blue Solar spectrum Photodegradation

ICRF Heated Long-Pulse Plasma Discharges in LHD

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Plasma Science and Technology 2006年第1期8卷 28-32页

作者： R. KUmAZAWA T. SEKI T. mUTOH K. SAITO T. WATARI Y. NAKAmURA m. SAKAmOTO T. WATANABE S. KUBO T. SHImOZUmA Y. YOSHImURA H. IGAmI Y. TAKEIRI Y. OKA K. TSUmORI m. OSAKABE K. IKEDA K. NAGAOKA O. KANEKO J. mIYAZAWA S. mORITA K. NARIHARA m. SHOJI S. mASUZAKI m. GOTO T. mORISAKI B. J. PETERSON K. SATO T. TOKUZAWA N. ASHIKAWA K. NISHImURA H. FUNABA H. CHIKARAISHI T. NOTAKE Y. TORII H. OKADA m. ICHImURA H. HIGAKI Y. TAKASE H. KASAHARA F. SHImPO G.NOmURA C.TAKAHASHI m.yokota A. KATO 赵燕平 J. S. YOON J. G. KWAK H. YAmADA K. KAWAHATA N. OHYABU K. IDA Y. NAGAYAmA N. NODA A. KOmORI S. SUDO O. mOTOJImA National Institute for Fusion Science Toki Japan Kyusyu University Kasuga Japan Nagoya University Faculty of Engineering Nagoya Japan Kyoto University Institute of Advanced Energy Uji Japan Tsukuba University Plasma Research Center Tsukuba Japan Tokyo University Graduate School of Frontier Sciences Tokyo Japan Institute of Plasma Physics Chinese Academy of Sciences Hefei 230031 China KAERI 150 Deogjin-dong Yuseong-gu Daejeon Korea Rep.

A long-pulse plasma discharge for more than 30 min. was achieved on the Large Helical Device （LHD）. A plasma of ne = 0.8 × 10^19 m^-3 and T10 = 2.0 keV was sustained with PICH = 0.52 mW, PECH = 0.1 mW and averaged PNBI = 0.067 mW. Total injected heating energy was 1.3 G J, which was a quarter of the prepared RF heating energy. One of the keys to the success of the experiment was a dispersion of the local plasma heat load to divertors, accomplished by shifting the magnetic axis inward and outward.

关键词： helical/stellarator configuration ICRF heating steady state operation

Nonlinear dynamic modeling of planar moving Timoshenko beam considering non-rigid non-elastic axial effects

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 479-496页

作者： m.ABBASI GAVARI m.R.HOmAEINEZHAD Faculty of mechanical Engineering K.N.Toosi University of TechnologyTehran 19991-43344Iran

Due to the importance of vibration effects on the functional accuracy of mechanical systems,this research aims to develop a precise model of a nonlinearly vibrating single-link mobile flexible *** manipulator consists of an elastic arm,a rotary motor,and a rigid carrier,and undergoes general in-plane rigid body motion along with elastic transverse *** accurately model the elastic behavior,Timoshenko’s beam theory is used to describe the flexible arm,which accounts for rotary inertia and shear deformation *** applying Newton’s second law,the nonlinear governing equations of motion for the manipulator are derived as a coupled system of ordinary differential equations(ODEs)and partial differential equations(PDEs).Then,the assumed mode method(Amm)is used to solve this nonlinear system of governing equations with appropriate shape *** assumed modes can be obtained after solving the characteristic equation of a Timoshenko beam with clamped boundary conditions at one end and an attached mass/inertia at the *** addition,the effect of the transverse vibration of the inextensible arm on its axial behavior is *** the axial rigidity,the effect makes the rigid body dynamics invalid for the axial behavior of the ***,numerical simulations are conducted to evaluate the performance of the developed model,and the results are compared with those obtained by the finite element *** comparison confirms the validity of the proposed dynamic model for the *** to the mentioned features,this model can be reliable for investigating the system’s vibrational behavior and implementing vibration control algorithms.

关键词： planar moving Timoshenko beam non-rigid non-elastic axial effect as-sumed mode method(Amm) nonlinear motion analysis

Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 543-562页

作者： H.m.FEIZABAD m.H.YAS Department of mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** Hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQm)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQm)