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1.
1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　ＩｒｏｎａｌｕｍｉｎｉｄｅｓｂａｓｅｄｏｎＦｅ3 Ａｌｈａｖｅｍａｎｙａｄｖａｎｔａｇｅｓｆｏｒｓｔｒｕｃｔｕｒａｌｕｓｅｓａｔｅｌｅｖａｔｅｄｔｅｍｐｅｒａｔｕｒｅｂｅｃａｕｓｅｏｆｔｈｅｉｒｅｘｃｅｌｌｅｎｔｃｏｒｒｏｓｉｏｎｒｅｓｉｓｔａｎｃｅａｎｄｒｅｌａｔｉｖｅｌｙｌｏｗｍａｔｅｒｉａｌｃｏｓｔ.Ｈｏｗｅｖｅｒ,ｔｈｅｓｅａｌｌｏｙｓｈａｖｅｎｏｔｙｅｔｆｏｕｎｄｗｉｄｅｓｐｒｅａｄｕｓｅｂｅｃａｕｓｅｔｈｅｙｅｘｈｉｂｉｔｐｏｏｒｄｕｃｔｉｌｉｔｙａｎｄｂｒ…  相似文献   

2.
The process of gaseous hydrogen charging into a Ti3Al-based alloy in the temperature range of 500–650°C is investigated. The results showe that the relationship between the average hydrogen concentration at constant temperature and charging time reveals a parabolic rate law. Applying the theory of lattice diffusion to analyze the hydrogen diffusion in the alloy, we find that the apparent activation energy of hydrogen diffusion is 90.40 kJ/mol, and the equilibrium hydrogen content in the alloy depends on the temperature of the gaseous hydrogen charging process. Project supported by the Natural Science Foundation of Shanghai (93QE14002)  相似文献   

3.
The western Iratsu mass, the largest tectonic body in the Sambagawa metamorphic belt, central Shikoku, is mainly composed of epidote amphibolite with minor amounts of eclogite. Systematically, a majority of garnets show bell-shaped chemical zoning of pyrope contents and Mg/(Mg Fe2 ) monotonously increasing outward. The grossular component in zonal garnet increases outwards, maximizes at an intermediate part, and then decreases towards the outermost rim, reflecting a process from increasing to decreasing pressure conditions during the prograde metamorphism. Jadeite contents of omphacite range from 25～20mole% within the cores to 15～10 mole% at the rims, implying a pressure-decreasing process (from 11 × 105 Pa to 8 × 105 Pa). The peak pressure-temperature (P-T) condition of 630～680 ℃ and ca. 15× 105 Pa in the western Iratsu mass is much higher than that of (610±25) ℃ and (10± 1)× 105 Pa of the Sambagawa oligoclase-biotite zone schists. The authors suggest a clockwise P-T-t path for the western Iratsu mass.  相似文献   

4.
Osteochondral allografting has been proved to be a useful method to treat diseased or damaged areas of joint surfaces. Operational long-term stocks of grafts which supply a buffer between procurement and utilization would contribute to the commercialization or industrialization of this technology. Vitrification has been thought to be a promising method for successful preservation of articular cartilage (AC), but high concentration cryoprotectants (CPAs) are used which may cause high cellular toxicity. An effective way to reduce CPA toxicity is to increase CPA concentration gradually while the temperature is lowered. Understanding the mechanism of CPA permeation at subzero temperatures is important for designing the cryopreservation protocol. In this research, the permeation of dimethyl sulfoxide (Me2SO) in ovine AC at subzero temperatures was studied experimentally. Pretreated AC discs were exposed in Me2SO solutions for different time (0, 5, 15, 30, 50, 80, and 120 min) at three temperature levels (−10, −20, and −30 °C). The Me2SO concentration within the tissue was determined by ultraviolet (UV) spectrophotometry. The diffusion coefficients were estimated to be 0.85×10−6, 0.48×10−6, and 0.27×10−6 cm2/s at −10, −20, and −30 °C, respectively, and the corresponding activation energy was 29.23 kJ/mol. Numerical simulation was performed to compare two Me2SO addition protocols, and the results demonstrated that the total loading duration could be effectively reduced with the knowledge of permeation kinetics.  相似文献   

5.
The room temperature tensile properties of cold-rolled and annealed Fe3(Al,Cr,Zr) alloy are similar to those of warm-rolled Fe3Al alloys. The cold-rolled Fe3(Al,Cr,Zr) alloy is also susceptible to test environments. It has been shown that the ductility in various environments decreases in sequence of oxygen-oil-air-distilled water. The results of X-ray diffraction analysis show that (211) preferred orientation of B2 phase appears in cold-rolled Fe3(Al,Cr,Zr) alloy after recrystallization annealing. Supported by the National Natural Science Foundation of China (59895157) and the Natural Science Foundation of Shanghai Municipal Commission of Science and Technology (98ZE14020)  相似文献   

6.
以木屑为原料,高温热解制备生物炭。以聚乙烯醇为粘结剂,采用混合法将生物炭与果胶复合,并负载磁性,经烘干定型制备果胶包覆的磁性生物炭材料（果胶@生物炭-Fe3O4）。采用扫描电镜（SEM）、X射线衍射（XRD）及N2吸附-脱附（BET）等方法对果胶@生物炭-Fe3O4进行表征,结合吸附实验分析其对Cu2+的吸附特性。结果表明,当生物炭、果胶、Fe3O4质量比为5：1：1,溶液pH值为6,吸附24 h,果胶@生物炭-Fe3O4对Cu2+吸附效果最好;二级动力学方程能较好地描述果胶@生物炭-Fe3O4对Cu2+的吸附过程,Freundlich模型能较好地拟合其吸附行为;SEM结果显示该材料具有不规则的孔隙结构;XRD分析显示纳米Fe3O4是其主要的晶体结构;BET测得其比表面积为25.654 m2·g-1,平均孔径为20.18 nm。  相似文献   

7.
In these studies, a vegetable can containing fluidwas swung as a pendulum by supporting its end-lipswith a pair of knife edges. The motion was measuredwith a capacitive sensor and the logarithmic decrementin free decay was estimated from computer-collectedrecords. Measurements performed with nine differenthomogeneous liquids, distributed through six decadesin the viscosity η, showed that the damping ofthe system is dominated by η rather than externalforces from air or the knife edges. The log decrementwas found to be maximum (0.28) in the vicinity ofη = 0.7 Pa s and fell off more than 15 fold(below 2 × 10-2) for both small viscosity(η < 1 × 10-3 Pa s) and also for largeviscosity (η > 1 × 103 Pa s). A simple modelhas been formulated, which yields reasonable agreementbetween theory and experiment by approximating therelative rotation of can and liquid.  相似文献   

8.
Well-cubic perovskite lanthanum aluminate (LaAlO3) film on (110) silicon substrate was fabricated by sol-gel method with corresponding inorganic salts. Lanthanum acetate and aluminum acetate glacial acetic acid solutions were prepared via ligand exchange starting from lanthanum nitrate hexahydrate and aluminum nitrate hexahydrate after being refluxed. (CH3CO)2O removed nitrates and the crystallized H2O completely, acetylacetone (AcAc) was partially bidentated with metallic ion of the metallic acetates and formed La(OAc)3−x (AcAc) x which were hydrolyzed into La(AcAc)3−x(OH) x by adding 10 ml 0.4% methyl cellulose (MCL) solution. The La(AcAc)3−x (OH) x , polymerizing and combining with MCL, formed the LaAlO3 sol precursor with heteropolymeric structure and formed film easily. The epitaxial LaAlO3 film on Si(110) substrate was crystallized after being annealed in thermal annealing furnace for 650–750 °C/30 min. The morphologies and microstructures were characterized. The refractive index of the LAO film was 1.942 to 2.007; the dielectric constant and the dissipation factors were estimated to be 23–26 and 2.1×10−4−2.4×10−4 respectively. Project (No. 2002CB613305) supported by the National Basic Research Program (973) of China  相似文献   

9.
1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　Ｔｈｅｃｈｅｍｉｃａｌｅｆｆｅｃｔｓｏｆｕｌｔｒａｓｏｕｎｄａｒｅｄｕｅｔｏｈｉｇｈｐｒｅｓｓｕｒｅｐｒｏｄｕｃｅｄｄｕｒｉｎｇｖｉｏｌｅｎｔｃｏｌｌａｐｓｅｏｆｃａｖｉｔａｔｉｏｎｂｕｂｂｌｅｓ.Ｔｈｅｒｅａｃｔｉｏｎｓｄｏｎｏｔｔａｋｅ ｐｌａｃｅｈｏｍｏｇｅ ｎｅｏｕｓｌｙｉｎｔｈｅｓｏｌｕｔｉｏｎｂｕｔｉｎ”ｈｏｔｓｐｏｔｓ”ｗｈｅｒｅｃａｖｉ ｔａｔｉｏｎｂｕｂｂｌｅｓｐｕｌｓａｔｅｏｒｃｏｌｌａｐｓｅ .Ｄｕｒｉｎｇｔｈｅａｄｉａｂａｔ ｉｃｃｏｍｐｒｅｓｓｉｏ…  相似文献   

10.
The cyclic oxidation behaviors of Fe-28Al-5Cr-O. 1Zr (at%) and Fe-28A15Cr-O. 5Nb (at%) alloys have been investigated in air at high temperature. The results show that the distinctive whisker-like oxides were formed on the surface of Zr-containing Fe3 Al based alloy after 500 hrs. cyclic oxidation at 800 °C and 1000 °C. The results also indicate that the addition of small amount of Zr to Fe3 Al based alloy can improve its adherence strength between the oxides and metal substrate and is beneficial to the oxidation resistance. However, for the Nb-containing Fe3 Al based alloy, porous convoluted oxides were formed after 350 hrs. cyclic oxidation at 1000°C, and this type of oxides didn’t not contribute to the oxidation resistance.  相似文献   

11.
Systematic studies of the transport properties of La0.67Ca0.33Mn1?xFe x O3 (x=0–0.3) systems showed that with increasing Fe-doping contentx the resistance increases and the insulator-metal transition temperature moves to lower temperature. For small doping content, the transport property satisfies metal transport behavior below the transition temperature, and above the transition temperature it satisfies the small polaron model. This behavior can be explained by Fe3+ doping, which easily forms Fe3+?O2??Mn4+ channel, suppressing the double exchange Mn3+?O2??Mn4+ channel and enhancing the spin scattering of Mn ions induced by antiferromagnetic clusters of Fe ions.  相似文献   

12.
In this study aimed to evaluate the pollution extent of metals and nonmetals inside and outside the ferrosilicon production factory in Edfu, Aswan, Egypt, raw materials (quartz, cokes, iron oxides), ferrosilicon alloy, silica fume, dust and suspended dust (at different sites) samples were collected from the factory, and fallen dust samples were collected from outside the factory, horizontally (at different sites and different distance and directions) and vertically (at different floors in the selected buildings). Gravimetric methods, X-ray fluorescence (XRF), flame photometer, wide range carbon determinator and atomic absorption spectroscopy tools were used for elements determination. The results indicating that the fallen dust and its element contents on southern factory walls being higher than those on eastern factory walls may be due to the nature of the dusts and effects of wind force and wind direction. Fallen dust levels in different regions outside the factory were found to be affected by the distance, direction and floors. The nature of dust samples was affected by gravity and the suspended dust in different factory units depended on the work capacity and method of handling materials by personnel in different production units. Silica fume was a complicated problem, had dangerous effect against the workers' health, and was characterized by high concentrations of SiO2(90.6%～93.6%) and heavy metals (Mn, 420.6×10-6～520.3×10-6; Fe, 2354×10-6～2685×10-6; Co, 80.7×10-6～101.6×10 6 and Ni,5.3× 10-6～6.05× 10-6). The TSP (Total Suspended Particulate) levels in all factory units were higher than the recommended air quality value (70 μg/m3) under Egyptian law. The effect of ferrosilicon factory fallen dust on the surrounding regions decreased with increasing distance between the factory and these regions. The suspended dust samples in the factory units and their components greatly exceeded national and international standards, so health and environmental criteria must be enforced on these units.  相似文献   

13.
Molecule matters     
The synthesis of a FeVI complex in an octahedral coordination geometry has been achieved recently by Wieghardt and coworkers. This is only the second hexavalent iron complex known after the tetrahedral ferrate ion, [FeO4]2?. The synthesis of the new FeVI complex involves a low temperature photolysis of an FeIV(N3) precursor which leads to the formation of the FeVI complex containing a Fe≡N triple bond. The structural characterization of the FeVI complex has been achieved by a variety of spectroscopic techniques including Mössbauer spectroscopy and X-ray absorption spectroscopy. Experimentally it is found that the FeVI complex is diamagnetic. Theoretical calculations reveal that the FeVI complex has an electronic configuration 3d2 (S = 0); the d electrons are paired in a dxy orbital.  相似文献   

14.
The magnetic properties of as-quenched and annealed Fe73.5Ag1Nb3Si13.5B9 alloys were investigated. X-ray diffraction was used to monitor the structure changes of the samples under different annealing temperatures. It was found that by Cu addition, the crystallization temperature T x1 of Fe-Nb-Si-B alloy is decreased, whereas by Ag addition, the T x1 is increased. A small amount of α-Fe and Ag were obtained after the sample was annealed at 500°C for 1 h. With increasing the annealing temperature, Fe23B6, Fe2B, Fe3B were separated out and magnetic properties of the samples were impaired quickly. A mostly single nanocrystalline grain of a-Fe phase could not be obtained in the annealed samples.  相似文献   

15.
Some laboratory diffusion tests were conducted with diffusion device to determine the diffusion coefficient of Cr(Ⅵ) ion passing through Dalian red clay samples. The concentrations of Cr(Ⅵ) at different places of the samples were then measured spectrophotometrically after a standing time of 1 000 d. A one-dimensional solute transport equation was used to simulate the transport of Cr(Ⅵ) through clay samples. Back-calculation of diffusion coefficient of Cr(Ⅵ) was made with finite difference method. Parametric analysis was conducted to simulate variations in soil dry density, temperature, pH and standing time. The results show that the method used in this paper is simple and effective. The diffusion coefficient of Cr(Ⅵ) in Dalian red clay varies from 1.50×10-7 cm2/s to 2.08×10-7 cm2/s. After 1 000 d diffusion, the concentration of the source solution drops down to 1.27 mg/L from 62.5 mg/L, and the diffusion distance is only 3.5 cm. Under the assumption that diffusion coefficient is constant, the diffusion effect becomes more obvious with lower density, lower temperature, higher pH value, and much more time.  相似文献   

16.
Ａｌｕｍｉｎｕｍ ＡｌｌｏｙｓTX１ＩｎｔｒｏｄｕｃｔｉｏｎＦｅ－Ａｌｉｎｔｅｒｍｅｔａｌｉｃｓｈａｖｅｇｒｅａｔｐｏｔｅｎｔｉａｌｉｔｉｅｓｆｏｒｓｔｒｕｃｔｕｒａｌａｐｐｌｉｃａｔｉｏｎｓｏｗｉｎｇｔｏｔｈｅｉｒｇｏｏｄｍｅｃｈａｎｉｃａｌｐｒｏｐ...  相似文献   

17.
The effect of magnetic field on α-amylase was studied. Under the experimental conditions, α-amylase solution was treated by 0.15 T, 0.30 T and 0.45 T static magnetic fields for a known period of time, then the activity, kinetic parameters, and the secondary conformation were investigated. The results showed that there was a considerable effect of the magnetic exposure on the α-amylase. The activity was increased by 27%, 34.1%, 37.8% compared with the control. It was also found that both kinetic parameters K m and V m could be decreased due to the increasing magnetic field, K m decreased from 2.20×10?2 to 0.87×10?2, whereas V m decreased from 2.0×10?3 g/min to 1.1×10?3 g/min. At the same time, there were some irregular changes in α-amylase secondary conformation.  相似文献   

18.
Electricity consumption increases rapidly with the rapid development of China. The environmental damage costs of electricity generation are very important for both policy analysis and the proper management of the environment. A method was developed in this work to estimate gross environmental damage costs according to emission inventory and environmental cost factors, and to extend the costs from provincial to national level with population density. In this paper, sulfur dioxide (SO2), nitrogen oxides (NOx), particulate matter less than 10 μm in diameter (PM10), and carbon dioxide (CO2) from fossil fired power plants over 6000 kW were selected as index pollutants to quantify the environmental costs of damages on human health and global warming. With the new developed method, environmental damage costs, caused by 3 types of fired power plants in 30 provinces and 6 economic sectors during the years 2000 to 2003, were evaluated and analyzed. It can be seen that the calculated total national environmental damage costs of electricity have rapidly increased from 94930.87×106 USD in 2000 to about 141041.39×106 USD in 2003, with an average annual growth rate of 14.11%. Environmental damage costs of SO2, NOx, PM10, and CO2 are 69475.69×106, 30079.29×106, 28931.84×106, and 12554.57×106 USD and account for 49.26%, 21.33%, 20.51%, and 8.90% of total environmental costs in fossil electricity generation, respectively. With regard to regional distribution, external costs caused by fossil electricity generation are mainly concentrated in the more populated and industrialized areas of China, i.e., the Eastern Central and Southeastern areas.  相似文献   

19.
1IntroductionThe synthesis and characterization of nano-struc-tured materials are the subject of intense current re-search.Hyperfineγ-Fe2O3particle with good perfor-mance,such as magnetism,catalysis,gas-sensitivityand so on,are widely applied in various fields[1].It ishighly significant to research and develop the methodsfor synthesis of nanometerγ-Fe2O3.With the development of nano-science and nano-technology,the methods for preparation ofγ-Fe2O3have been greatly progressed,for example,…  相似文献   

20.
INTRODUCTION Nitrogen oxide (NOx) is one of the main air pol- lutants found in the flue gases from chemical and power plants belching acid rain and photochemical smog. Over 90 percent of all man-made nitrogen ox- ides that enter our atmosphere are produced by the combustion of various fuels. Compared with the ad- vanced stage of SO2 gas removal technologies devel- opment, the removal of NOx gases is still in the initial stages of development as roughly 90 to 95 percent of NOx emitted i…  相似文献   

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