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THE INVESTIGATION ON THE RHEOLOGICAL BEHAVIOR OF SEMI-SOLID ALUMINUM ALLOY DURING DIE CASTING

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Acta Metallurgica Sinica(English Letters) 2002年第6期15卷 511-516页

作者： X.j. Yang and j.Liu School of Mechanic & Electronic Engineering, Nanchang University, jiangxi 330029, China School of Mechanic & Electronic Engineering, Shanghai University, Shanghai 200072, China Sch. of Mech. and Electron. Eng. Nanchang Univ. Nanchang 330029 China Sch. of Mech. and Electron. Eng. Shanghai Univ. Shanghai 200072 China

Under the condition of die casting and reheating temperature of 570-580 degC, the rheological behavior of semi-solid aluminum alloy (A356) is pseudoplasticity at the shearrate of 2X10^-1X10^4s^(-1), and also shows dil... 详细信息

关键词： shear rate apparent viscosity viscosity model thixocasting

EFFECTS OF Pb COMPOUND ADDITIVES ON THE PROPERTIES OF YBa_2Cu_3O_(7-δ)

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Acta Metallurgica Sinica(English Letters) 2005年第2期18卷 145-148页

作者： F.H.Li Z.G.Fan j.Wang C.S.Liu D.W.Soh Y.j.Cho SchoolofMaterialandMetallurgy NortheasternUniversityShenyang110004China MyongjiUniversity Yongjin449-728SouthKorea

The melting temperature and critical transition temperature Tc of YBa2Cu3O7-δ with deferent content additives of PbO and BaPbO3 were studied. When PbO was doped in YBa2Cu3O7-δ, the melting temperature of YBa2Cu3O7-δ was reduced, however its superconductivity was weakened. From the XRD pattern of the sintered mixture of YBa2Cu3O7-δ and PbO, it was known that there was a reaction between YBa2Cu3O7-δ and PbO, and the product was BaPbO3. Hence different contents of BaPbO3 (10mass%, 20mass% and 30mass%) were added in YBa2Cu3O7-δ. It was proved that there were no reactions between YBa2Cu3O7-δ and BaPbO3. And the superconductivity of the mixtures was much better than that of the samples with PbO additive.

关键词： YBa2Cu3O7-δ PbO additive melting temperature superconductivity

Additive manufacturing of Sm-Fe-N magnets

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journal of Rare Earths 2019年第10期37卷 1078-1082页

作者： j.A.B.Engerroff A.B.Baldissera M.D.Magalhaes P.H.Lamarao P.A.P.Wendhausen C.H.Ahrens j.M.Mascheroni Department of Mechanical Engineering Federal University of Santa CatarinaFlorianopolisBrazil AlkimatTecnologia Sao JoseBrazil

Isotropic Sm-Fe-N bonded magnets were obtained by additive manufacturing(AM). The technique used was the so-called powder bed fusion(PBF) and the feedstock was composed of a polymeric binder(PA-12) and Sm-Fe-N flake particles(Nitroquench-P). The AM set-up equipment uses a computer-controlled CO2 laser beam to melt the binder and constructs magnets layer-by-layer. In order to develop this study, a cylinder with 10 mm of both height and diameter was selected as the shape of samples. Specimens were analyzed by scanning electron microscopy(SEM) and X-ray diffraction(XRD). Magnetic properties were measured in a hysteresis graph. XRD results indicate that there is no degradation of the main magnetic phase(SmFe7 Nx). In the AM component, porous regions were identified on SEM micrographs, as well as magnetic particles and polymeric binder. Remanence values(Br) as great as 0.3 T are achieved, while intrinsic coercivities remain in the range from 616 up to 642 kA/m. An additional isostatic compression of the parts results in greater remanence, which is directly proportional to the density increase. Coercivity is also sensitive to the porosity decrease, probably due to a better interlocking of particles. Current results indicate AM as a promising route for near net-shape manufacturing of Sm-Fe-N permanent magnets, a market niche yet to be widely explored.

关键词： Sm-Fe-N Permanent magnets Additive manufacturing Rare earths

The Characterization of Sputtered Zr-Ge-N Thin Films as Diffusion Barriers Between Copper and Silicon

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稀有金属材料与工程 2012年第S1期41卷 120-123页

作者： Yang, j. j. Liu, B. Liao, X. D. jiao, G. H. Xu, K. W. Sichuan Univ Inst Nucl Sci & Technol Minist Educ Key Lab Radiat Phys & Technol Chengdu 610064 Peoples R China CAS Xian Inst Opt & Precis Mech State Key Lab Transient Opt & Photon Xian 710049 Peoples R China Xi An jiao Tong Univ State Key Lab Mech Behav Mat Xian 710049 Peoples R China

The main purpose of the present micro-structural analysis by transmission electron microscopy(TEM)and X-ray diffraction(XRD)was to investigate whether amorphous Zr-Ge-N films are a potential candidate as a diffusion barrier for Cu wiring used in Si *** Zr-Ge-N films were prepared by a radio frequency(RF)reactive magnetron sputter-deposition technique using N2 and Ar mixed gas,and the film structure was found to be sensitive to the gas flow ratio of N2 *** during *** Zr-Ge-N films were obtained when the N2/(Ar+N2)ratio was smaller than 0.2 and amorphous-like Zr-Ge-N films were obtained when the ratio was larger than *** barrier test was performed by annealing the Cu/Zr-Ge-N/Si film stack under Ar *** deposited Zr-Ge-N(C)films remained amorphous even after high temperature *** Cu diffusion profile in the film was assessed by the Auger electron spectroscopy(AES).The results indicate that Cu diffusion was minimal in amorphous Zr-Ge-N(C)films even at high annealing temperatures of 800℃.

关键词： Zr-Ge-N films diffusion barrier micro-structural thermal stability

Temperature-controlled mode selection of Er-doped random fiber laser with disordered Bragg gratings

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Photonics Research 2016年第3期4卷 102-105页

作者： W.L.Zhang Y.B.Song X.P.Zeng R.Ma Z.j.Yang Y.j.Rao Key Laboratory of Optical Fiber Sensing & Communications (Education Ministry of China) University of Electronic Science & Technology of China

In this paper, we proposed a way to realize an Er-doped random fiber laser(RFL) with a disordered fiber Bragg grating(FBG) array, as well as to control the lasing mode of the RFL by heating specific locations of the disordered FBG array. The disordered FBG array performs as both the gain medium and random distributed reflectors, which together with a tunable point reflector form the RFL. Coherent multi-mode random lasing is obtained with a threshold of between 7.5 and 10 mW and a power efficiency between 23% and 27% when the reflectivity of the point reflector changes from 4% to 50%. To control the lasing mode of random emission, a specific point of the disordered FBG array is heated so as to shift the wavelength of the FBG(s) at this point away from the other ***, different resonance cavities are formed, and the lasing mode can be controlled by changing the location of the heating point.

关键词： mode Temperature-controlled mode selection of Er-doped random fiber laser with disordered Bragg gratings

Giant Magneto-impedance Effect in Composite Wires with Different Core Layer

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Nano-Micro Letters 2013年第2期5卷 140-144页

作者： R.L.Wang X.Li X.H.Kong Y.X.Guo j.Z.Ruan Z.j.Zhao Department of Physics Engineering Research Center for Nanophotonics & Advanced Instrument Ministry of Education East China Normal University Experimental Teaching Center of Physics Shanghai Ocean University

Composite structure materials were potential sensing elements for magnetic sensors due to Giant magnetoimpedance(GMI) effect. Two kinds of composite wires with different magnetic/non-magnetic structures were fabricated by using electroless deposition methods and the magnetoimpedance properties were investigated. The maximum GMI ratio of 114% was acquired at 60 MHz in the composite wires with a ferromagnetic core, whereas, 116% of maximum GMI ratio was found in the composite wires with a conductive core at low frequency of 600 k Hz. These results exhibit that the GMI ratio reaches the maximum when magnetoresistance ratio ?R/R and magnetoinductance ratio ?X/X make the comparative contributions to the total magnetoimpedance(MI). The obvious GMI effect obtained in the composite wires with conductive core frequency may provide a candidate for applications in magnetic sensors, especially at low frequencies.

关键词： Composite wires Electroless deposition Giant Magnetoimpedance effect Resistivity

INFLUENCE OF SO_4^(2-) AND Cl-ON THE CORROSION BEHAVIOR OF COPPER TUBE IN AIR-CONDITIONING SYSTEM

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Acta Metallurgica Sinica(English Letters) 2004年第1期17卷 92-96页

作者： C.S.Wu Z.Zhang F.H.Cao j.Q.Zhang j.M.Wang C.N.Cao Department of Chemistry Yuquan CampusZhejiang University Hangzhou 310027ChinaDepartment of Chemistry Yuquan CampusZhejiang University Hangzhou 310027ChinaDepartment of Chemistry Yuquan CampusZhejiang University Hangzhou 310027ChinaDepartment of Chemistry Yuquan CampusZhejiang University Hangzhou 310027China State Key Laboratory for Corrosion and Protection of Metals Shenyang 110016 ChinaDepartment of ChemistryYuquan Campus Zhejiang University Hangzhou 310027ChinaDepartment of ChemistryYuquan Campus Zhejiang University Hangzhou 310027China State Key Laboratory for Corrosion and Protection of MetalsShenyang 110016 China

The influence of chloride or sulphur dioxide on the corrosion behavior of copper tube in the air-conditioning system was studied using scanning electron microscope (SEM), energy dispersion spectrometer (EDS) and cyclic polarization techniques. The results showed that the corrosion of copper tube are mainly caused by the SO42- and Cl- ions in the circulating water, and the former is mainly responsible for the general corrosion of the copper tube whilst the latter for the pitting corrosion. The different influences of SG42- and Cl- ions on the corrosion type of copper tube may be attributed to that the radius of SO42- ion is much larger than that of Cl- ion. Meanwhile the results also indicated that SO42- inhibits the pitting corrosion caused by Cl- and Cl- inhibits the general corrosion initiated by SO42- due to their competitive adsorption on the copper matrix.

关键词： copper corrosion behavior influence SO42- ion Cl- ion

Prolonged feeding with guanidinoacetate, a methyl group consumer, exacerbates ethanol-induced liver injury

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World journal of Gastroenterology 2016年第38期22卷 8497-8508页

作者： Natalia A Osna Dan Feng Murali Ganesan Priya F Maillacheruvu David j Orlicky Samuel W French Dean j Tuma Kusum K Kharbanda Research Service Veterans Affairs Nebraska-Western Iowa Health Care System Department of Internal Medicine 982000 Nebraska Medical Center Department of Pathology University of Colorado Denver Department of Anatomic Pathology Harbor UCLA Medical Center Department of Biochemistry and Molecular Biology 985870 Nebraska Medical Center

AIM To investigate the hypothesis that exposure to guanidinoacetate(GAA, a potent methyl-group consumer) either alone or combined with ethanol intake for a prolonged period of time would cause more advanced liver pathology thus identifying methylation defects as the initiator and stimulator for progressive liver *** Adult male Wistar rats were fed the control or ethanolLieber De Carli diet in the absence or presence of GAA supplementation. At the end of 6 wk of the feeding regimen, various biochemical and histological analyses were conducted. RESULTS Contrary to our expectations, we observed that GAA treatment alone resulted in a histologically normal liver without evidence of hepatosteatosis despite persistence of some abnormal biochemical parameters. This protection could result from the generation of creatine from the ingested GAA. Ethanol treatment for 6 wk exhibited changes in liver methionine metabolism and persistence of histological and biochemical defects as reported before. Further, when the rats were fed the GAA-supplemented ethanol diet, similar histological and biochemical changes as observed after 2 wk of combined treatment, including inflammation, macroand micro-vesicular steatosis and a marked decrease in the methylation index were noted. In addition, rats on the combined treatment exhibited increased liver toxicity and even early fibrotic changes in a subset of animals in this group. The worsening liver pathology could be related to the profound reduction in the hepatic methylation index, an increased accumulation of GAA and the inability of creatine generated to exert its hepato-protective effects in the setting of *** To conclude, prolonged exposure to a methyl consumer superimposed on chronic ethanol consumption causes persistent and pronounced liver damage.

关键词： Methyl balance S-adenosylmethionine S-adenosylhomocysteine Guanidinoacetate Alcohol

Understanding temporal stability:a long-term analysis of USDA ARS watersheds

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International journal of Digital Earth 2021年第10期14卷 1243-1254页

作者： Evan j.Coopersmith Michael H.Cosh Patrick j.Starks David D.Bosch Chandra Holifield Collins Mark Seyfried Stan Livingston john Prueger Soil Insight LLCWashington D.C.USA USDA-Agricultural Research Service Beltsville Agricultural Research CenterHydrology and Remote Sensing LaboratoryBeltsvilleUSA USDA-Agricultural Research Service-Grazinglands Research Laboratory El RenoUSA USDA-Agricultural Research Service-Southeast Watershed Research Laboratory TiftonUSA USDA-Agricultural Research Service-Southwest Watershed Research Center TucsonUSA USDA-Agricultural Research Service-Northwest Watershed Research Laboratory BoiseUSA USDAAgricultural Research Service-National Soil Erosion Research Laboratory West LafayetteUSA USDA-Agricultural Research Service-National Laboratory for Agriculture and Environment AmesUSA

The *** of Agriculture’s Agricultural Research Service(USDAARS)maintains seven in situ soil moisture networks throughout the continental United States,some since *** networks are crucial for understanding the spatial and temporal extent of droughts in their historical context,parameterization of hydrologic models,and local agricultural decision ***,the estimates from these networks are dependent upon their ability to provide reliable soil moisture information at a large *** is also not known how many network stations are sufficient to monitor watershed scale ***,the objectives of this research were to:(1)determine how temporally stable these networks are,including the relationships between various sensors on a year-to-year and seasonal basis,and(2)attempt to determine how many sensors are required,within a network,to approximate the full network *** data from seven in situ,it is concluded that approximately 12 soil moisture sensors are sufficient in most environments,presuming their locations are distributed to capture the hydrologic heterogeneity of the *** is possible to install a temporary network containing a suitable number of sensors for an appropriate length of time,glean stable relationships between locations,and retain these insights moving forward with fewer sensor resources.

关键词： Soil moisture temporal stability in situ networks