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Sinogram fusion-based metal artifact correction method 被引量:1
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作者 李元金 舒华忠 +4 位作者 肖刚 王涛 孔佑勇 王杨 史小勇 《Journal of Southeast University(English Edition)》 EI CAS 2017年第2期145-149,共5页
To solve the problem that metal artifacts severely damage the clarity of the organization structure in computed tomography(CT) images, a sinogram fusion-based metal artifact correction method is proposed. First, the... To solve the problem that metal artifacts severely damage the clarity of the organization structure in computed tomography(CT) images, a sinogram fusion-based metal artifact correction method is proposed. First, the metal image is segmented from the original CT image by the pre-set threshold. The original CT image and metal image are forward projected into the original projection sinogram and metal projection sinogram, respectively. The interpolation-based correction method and mean filter are used to correct the original CT image and preserve the edge of the corrected CT image, respectively. The filtered CT image is forward projected into the filtered image sinogram. According to the position of the metal sinogram in the original sinogram and filtered image sinogram, the corresponding sinograms PM^D ( in the original sinogram) and PM^C ( in the filtered image sinogram)can be acquired from the original sinogram and filtered image sinogram, respectively. Then, PM^D and PM^C are fused into the fused metal sinogram PM^F according to a certain proportion.The final sinogram can be acquired by fusing PM^F , PM^D and the original sinogram P^O. Finally, the final sinogram is reconstructed into the corrected CT image and metal information is compensated into the corrected CT image.Experiments on clinical images demonstrate that the proposed method can effectively reduce metal artifacts. A comparison with classical metal artifacts correction methods shows that the proposed metal artifacts correction method performs better in metal artifacts suppression and tissue feature preservation. 展开更多
关键词 metal artifacts interpolation-based method sinogram fusion-based computed tomography(CT) image
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Oxidation behavior of Zr-containing Ti_2AlNb-based alloy at 800°C 被引量:2
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作者 党薇 李金山 +1 位作者 张铁邦 寇宏超 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第3期783-790,共8页
The oxidation behavior of Ti?22Al?(27?x)Nb?xZr (x=0, 1, 6) alloys at 800 °C for exposure time up to 100 h was examined. It is shown that oxidation rate of experimental alloys obeys the parabolic kinetics. Ti?22Al... The oxidation behavior of Ti?22Al?(27?x)Nb?xZr (x=0, 1, 6) alloys at 800 °C for exposure time up to 100 h was examined. It is shown that oxidation rate of experimental alloys obeys the parabolic kinetics. Ti?22Al?26Nb?1Zr alloy demonstrates more excellent oxidation resistance than the other two alloys. The main oxidation products are TiO2, Al2O3 and AlNbO4 phases for all these alloys. For the Ti?22Al?26Nb?1Zr alloy, Zr addition can modify the growth mechanism of oxide scale, which can effectively hinder the diffusion of oxygen. Whereas, reaction of Zr with oxygen leads to the formation of ZrO2 precipitates for the Ti?22Al?21Nb?6Zr alloy, which promotes the oxygen ingress into the substrate. Meanwhile, oxidation affected zones, including internal-oxidation layer and oxygen-enriched zone, are present beneath the outmost oxide scale. The difference in these zones is derived from the phase constitution in the starting Ti?22Al?(27?x)Nb?xZr (x=0, 1, 6) alloys. 展开更多
关键词 oxidation behavior Ti2AlNb-based alloy ZR oxide scale oxidation affected zone
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Microstructures and mechanical properties of laser welded wrought fine-grained ZK60 magnesium alloy 被引量:1
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作者 严红革 赵嫱 +2 位作者 陈瓶 陈吉华 苏斌 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第2期389-396,共8页
Fine-grained ZK60 magnesium alloy sheets of 2.0 mm in thickness were successfully joined by laser beam welding (LBW). The effects of welding parameters including laser power and welding speed on the microstructures ... Fine-grained ZK60 magnesium alloy sheets of 2.0 mm in thickness were successfully joined by laser beam welding (LBW). The effects of welding parameters including laser power and welding speed on the microstructures and mechanical properties of the joints were investigated. A sound bead, with the ultimate tensile strength (UTS) of 300 MPa and elongation of 12.0%, up to 92.5% and 65% of those of the base metal, respectively, is obtained with the optimized welding parameters. No liquation cracking is visible in the partially melted zone (PMZ) owing to the inhibitory action of the fine dispersed precipitates and the fine-grained microstructure in the as-rolled magnesium alloy sheets. The fusion zone (FZ) is featured with the equiaxed dendritic grains of the average grain size about 8 μm, which are similar to those in the heat affected zone (HAZ), and this contributes to the relatively high joint efficiency. 展开更多
关键词 ZK60 magnesium alloy fine grain size laser beam welding heat affected zone partially melted zone
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An algorithm supporting fast scheduling and viewing of remote sensing images in embedded devices
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作者 李玲 王庆 +1 位作者 张小国 王慧青 《Journal of Southeast University(English Edition)》 EI CAS 2011年第3期270-274,共5页
In order to resolve the conflict between the limited resources of embedded devices and the growing amount of massive image data to be shown, a solution for fast images rendering in embedded devices is proposed and imp... In order to resolve the conflict between the limited resources of embedded devices and the growing amount of massive image data to be shown, a solution for fast images rendering in embedded devices is proposed and implemented. First, an improved algorithm of a multi-resolution file-pyramid construction which is used for the organization of massive image data is presented. Then, a strategy, adopting technologies such as view-dependent levels of detail, target-tiles quick search and tiles seamless connection, is presented for fast scheduling and viewing of images. The results show that compared with the solution of multi-scale image representations based on wavelet, the proposed solution can improve the rendering speed, and the rendering speed does not depend on the image size, though it increases some data storage space. And the proposed solution is suitable for embedded devices and friendly experience. 展开更多
关键词 interaction as because it can provide real-time well as more efficient user embedded devices PYRAMID levels of detail image rendering
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IMAGING CHARACTERISTICS OF RAT MODELS OF PARKINSON DISEASE
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作者 胡光霞 钱志余 +3 位作者 孙涛 杨天明 王文宏 谢捷如 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2010年第1期39-44,共6页
Imaging technologies are utilized to study the brain morphology and the functions of rat models of Parkinson disease (PD). Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) are used to ob... Imaging technologies are utilized to study the brain morphology and the functions of rat models of Parkinson disease (PD). Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) are used to obtain morphological imaging data. Functional imaging data, such as the spectrum and blood flow changes are obtained by proton magnetic resonance spectroscopy (1H-MRS) and CT perfusion (CTP). Results show that PD rat models have no characteristic morphological imaging abnormalities, but exist regional cerebral blood flow (CBF) reductions and spectral changes in the striatum. 展开更多
关键词 medical imaging brain morphology Parkinson disease magnetic resonance imaging CT perfusion
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Reliability analysis of structure with random parameters based on multivariate power polynomial expansion 被引量:1
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作者 李烨君 黄斌 《Journal of Southeast University(English Edition)》 EI CAS 2017年第1期59-63,共5页
A new method for calculating the failure probabilityof structures with random parameters is proposed based onmultivariate power polynomial expansion, in which te uncertain quantities include material properties, struc... A new method for calculating the failure probabilityof structures with random parameters is proposed based onmultivariate power polynomial expansion, in which te uncertain quantities include material properties, structuralgeometric characteristics and static loads. The structuralresponse is first expressed as a multivariable power polynomialexpansion, of which the coefficients ae then determined by utilizing the higher-order perturbation technique and Galerkinprojection scheme. Then, the final performance function ofthe structure is determined. Due to the explicitness of theperformance function, a multifold integral of the structuralfailure probability can be calculated directly by the Monte Carlo simulation, which only requires a smal amount ofcomputation time. Two numerical examples ae presented toillustate te accuracy ad efficiency of te proposed metiod. It is shown that compaed with the widely used first-orderreliability method ( FORM) and second-order reliabilitymethod ( SORM), te results of the proposed method are closer to that of the direct Monte Carlo metiod,and it requires much less computational time. 展开更多
关键词 RELIABILITY random parameters multivariable power polynomial expansion perturbation technique Galerkin projection
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GENETIC OPTIMIZATION OF HOT FILAMENT PARAMETERS IN HFCVD SYSTEM
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作者 宋胜利 左敦稳 +3 位作者 王珉 相炳坤 卢文壮 黎向锋 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2003年第1期42-46,共5页
In HFCVD system the substrate temperature is a key factor which deeply affects the quality of diamond films. Th e magnitude and the variation of the substrate temperature must be limited in a suitable range to depo... In HFCVD system the substrate temperature is a key factor which deeply affects the quality of diamond films. Th e magnitude and the variation of the substrate temperature must be limited in a suitable range to deposit diamond films of uniform thickness over large areas. In this paper, the hot filament parameters are investigated on the basi s of GAs to realize a good substrate temperature profile. Computer simulations d emonstrate that on parameters optimized by GAs a uniform substrate temperatur e field can be formed over a relatively large circle area with R s=10 cm. 展开更多
关键词 hot filament chemical vapor deposition temperature field genetic algorithms optimization diamond fi lm
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Microstructure and mechanical properties of heat affected zone in multi-pass GMA welded Al-Zn-Mg-Cu alloy 被引量:3
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作者 Jia-liang ZHOU Feng-yuan SHU +3 位作者 Hong-yun ZHAO Yao-hui Lü Yu-xin LIU Peng HE 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2019年第11期2273-2280,共8页
Microstructure and mechanical properties of the heat affected zone(HAZ)in multi-pass gas metal arc(GMA)welded Al Zn Mg Cu alloy plates were investigated,based upon which the mechanical anisotropy and fracture mechanis... Microstructure and mechanical properties of the heat affected zone(HAZ)in multi-pass gas metal arc(GMA)welded Al Zn Mg Cu alloy plates were investigated,based upon which the mechanical anisotropy and fracture mechanism were analyzed.The microstructure and composition were analyzed by scanning electron microscope(SEM)and energy dispersive spectroscope(EDS).X-ray diffractometer(XRD),transmission electron microscope(TEM)and selective area electron diffraction(SAED)were used to analyze the phase composition.The distribution of microhardness was identified as gradual transition and tensile strength had a tendency to decrease first and then increase.The distribution of nano-sizedη(MgZn2)particles in theα(Al)matrix and Al2MgCu phase determined the tensile performances along the thickness direction and led to the formation of ductile/brittle composite fracture in the HAZ.The continuous distribution of Al2MgCu phase in the strip intergranular precipitates gave birth to premature cracks and the brittle fracture region.The precipitated particles coarsening also led to the deterioration of mechanical properties. 展开更多
关键词 Al-Zn-Mg-Cu alloy heat affected zone microstructure mechanical properties ductile/brittle composite fracture
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Environmental impact assessment of magnesium alloy automobile hub based on life cycle assessment 被引量:3
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作者 YI Qiu-ping TANG Chang-ping 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第8期1870-1878,共9页
In order to find out the impact of aluminum alloy hub replaced by the magnesium alloy hub on environment,the resource consumption,energy consumption and pollutant emission during hub production and their service life ... In order to find out the impact of aluminum alloy hub replaced by the magnesium alloy hub on environment,the resource consumption,energy consumption and pollutant emission during hub production and their service life of the two types of hubs are investigated based on the life cycle assessment(LCA)theory.The results indicate that the adverse impact on environment can be effectively reduced by the application of magnesium alloy hubs.Compared with aluminum alloy hubs,the global warming potential(GWP)and human toxicity potential(HTP)are reduced by 39.6%and 24.0%,respectively.CO2 is the main pollutant in the life cycles of the two kinds of hubs,which is generated throughout the whole life cycle including the fabrication process and the service life,while the pollutants of particles mainly come from the fabrication stage.Compared with the aluminum alloy hubs,the green effect brought by magnesium alloy hubs is mainly due to the reduction of fuel consumption caused by weight loss. 展开更多
关键词 life cycle assessment theory magnesium alloy aluminum alloy HUB environmental impact
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Dynamic response pattern of gold prices to economic policy uncertainty 被引量:4
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作者 Gao CHAI Da-ming YOU Jin-yu CHEN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2019年第12期2667-2676,共10页
Based on a time-varying parameter structural vector autoregression with stochastic volatility(TVP-SVAR-SV)model,the time-varying effects and country differences of economic policy uncertainty(EPU)on gold prices from A... Based on a time-varying parameter structural vector autoregression with stochastic volatility(TVP-SVAR-SV)model,the time-varying effects and country differences of economic policy uncertainty(EPU)on gold prices from August 2006 to December 2017 were examined.The results show that the effects of global economic policy uncertainty(GEPU)shock on gold prices change over time.The changes were positive during 2006-2008 and 2013-2017,while the impacts were negative during 2009-2012,implying that the efficiency of gold as a safe haven is not stable and depends on economic conditions.There are significant country differences regarding the impact of EPU on the price of gold,particularly during the international financial crisis,European debt crisis and Trump election.During the international financial crisis,EPU exerts a positive impact on gold prices in most countries.During the European debt crisis,the impact of EPU on gold prices is mainly negative in the examined countries.While during the Trump election,the impact displays positive and negative alternating in most countries. 展开更多
关键词 economic policy uncertainty gold price time-varying effects TVP-SVAR-SV model
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Effects of Radix Curcumae Fungicides on Tobacco Brown Spot and Yield of Flue-cured Tobacco Leaves
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作者 田兰 梅桂勇 +1 位作者 龙章富 罗定棋 《Agricultural Science & Technology》 CAS 2016年第7期1736-1737,1748,共3页
This study aimed to investigate the effects of Radix Curcumae fungicides on tobacco brown spot and yield of flue-cured tobacco leaves. Through field experi- ments, control efficiency of Radix Curcumae fungicides again... This study aimed to investigate the effects of Radix Curcumae fungicides on tobacco brown spot and yield of flue-cured tobacco leaves. Through field experi- ments, control efficiency of Radix Curcumae fungicides against tobacco brown spot was investigated. The results showed that the average control efficiency of 400-fold, 600-fold and 800-fold Radix Curcumae fungicides against tobacco brown spot reached 37.83%, 34.09% and 24.32%, respectively. This study could provide the ba- sis for screening and application of plant-derived fungicides against tobacco brown spot. 展开更多
关键词 Curcumae extract Tobacco brown spot Control efficiency EFFECT
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Numerical Simulation on Nugget Formation and Evolution in Spot Welding of Aluminum Alloy 被引量:1
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作者 程方杰 张建优 +1 位作者 胡绳荪 单平 《Transactions of Tianjin University》 EI CAS 2011年第1期28-32,共5页
With the squeeze of electrode tips, the oxide film on aluminum (Al) alloy surface is broken and numbers of micro-gaps are formed randomly. The micro-gaps act as conducting spots at the beginning of welding, so the con... With the squeeze of electrode tips, the oxide film on aluminum (Al) alloy surface is broken and numbers of micro-gaps are formed randomly. The micro-gaps act as conducting spots at the beginning of welding, so the contact resistance is extremely high and unstable in spot welding of Al alloy. In this paper, a new contact resistance model is adopted to simulate the nugget forming process. This model describes the random distribution characteristic of conducting spots. The simulation results indicate that, within the first 5 ms of welding current (AC, 50 Hz), the temperature distribution at the workpieces interface is seriously irregular. In addition, the nugget does not nucleate from the weld center and grow continuously, however, it nucleates randomly from several points almost instantaneously and then merges into an entity quickly. Experimental results agreed with the numerical simulation. 展开更多
关键词 aluminum alloy spot welding NUGGET oxide film contact resistance
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Theoretical Studies on Photoionization Cross Sections of Solid Gold
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作者 MAXiao-Guang SUNWei-Guo CHENGYan-Song 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第1期159-164,共6页
Accurate expression for photoabsorption (photoionization) cross sections of high density system proposed recently is used to study the photoionization of solid gold. The results show that the present theoretical photo... Accurate expression for photoabsorption (photoionization) cross sections of high density system proposed recently is used to study the photoionization of solid gold. The results show that the present theoretical photoianization cross sections have good agreement both in structure and in magnitude with the experimental results of gold crystal. The studies also indicate that both the real part epsilon' and the imaginary part epsilon' of the complex dielectric constant epsilon and the dielectric influence function of a nonideal system have rich structures in low energy side with a range about 50 eV, and suggest that the influence of particle interactions of surrounding particles with the photoionized particle on the photoionization cross sections can be easily investigated using the dielectric influence function. The electron overlap effects are suggested to be implemented in the future studies to improve the accuracy of theoretical photoionization cross sections of a solid system. 展开更多
关键词 photoionization cross section solid gold dielectric influence function
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Fractionation of Added Cadmium in Submerged Soils asAffected by Organic Materials
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作者 WANGGUO GAOSHAN 《Pedosphere》 SCIE CAS CSCD 1999年第2期177-184,共8页
The effect of three organic materials (rice straw, Chinese milk vetch and pig manure) on the fractionationof cadmium added into two soils (a red soil and a fiuvo-aquic soil) was studied using submerged incubationexper... The effect of three organic materials (rice straw, Chinese milk vetch and pig manure) on the fractionationof cadmium added into two soils (a red soil and a fiuvo-aquic soil) was studied using submerged incubationexperiment. The organic materials increased soil solid organic carbon (SOC), pH value, the concentration ofactive Si in all the treatments and active Fe and Mn in some treatments. Accumulated SOC caused directlythe increase of Cd bound to solid organic matter and consequently the decrease of exchangeable Cd. Higheractive Si and pH, as well as lower Eh, were also responsible for the reduction of exchangeable Cd. Cd boundto Mn oxide was positively correlated with pH values and rose significatly after one-month incubation, butdecreased after three-month incubstion. Cd bound to amorphous Fe oxide increased with the incubationtime, but was not effected significantly by adding organic materials. 展开更多
关键词 CADMIUM FRACTIONATION organic materials solid organic carbon (SOC) submerged soil
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Relationship between impact of dose distribution and energy of radioactive ray for metal contraceptive ring 被引量:2
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作者 Jianwen Zhang Huiqun Luo Bo Yang Haowen Pang 《The Chinese-German Journal of Clinical Oncology》 CAS 2010年第8期482-485,共4页
Objective: We studied the relationship between impact of dose distribution and energy of radioactive ray in teletherapy with contraceptive ring. Methods: The SI Virtual Water Phantom was used to monitor medium of do... Objective: We studied the relationship between impact of dose distribution and energy of radioactive ray in teletherapy with contraceptive ring. Methods: The SI Virtual Water Phantom was used to monitor medium of dose. PTW ionization chamber was used to detect the dose. AP-PA (10 cmx 10 cm) and SAD technique were adopted. Monitoring dose of different locations with different energy of radioactive ray in AP and PA respectively with and without contraceptive ring, repeated 5 times. Results: Dose of with contraceptive ring was lower than that of without contraceptive ring in AP 6 MV- X-ray (P 〈 0.05), while in PA was no obvious difference (P 〉 0.05). Dose of except for the center was higher than that of without contraceptive ring in AP and PA 15 MV-X-ray (P 〈 0.05). For locations, doses of the upper, the left and right were higher than that of the center in AP 6 MV-X-ray (P 〈 0.05), while in PA was lower (P 〉 0.05). In AP and PA 15 MV-X-ray, doses of the upper, the left and right was higher than that of the center (P 〈 0.05). Conclusion: Metallic contraceptive ring would effect the dose distribution of radioactive ray, but influence degree related to locations of contraceptive ring and energy of radioactive ray. 展开更多
关键词 contraceptive ring RADIOTHERAPY DOSE
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STUDY ON THE MECHANISMS OF EROSION OF METALS AT LOW IMPACT ANGLE
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作者 林福严 邵荷生 《Journal of China University of Mining and Technology》 1991年第1期117-125,共9页
The mechanisms of solid particle erosion of several pure metals and steels at low impact angle were studied comprehensively by SEM observations of the worn surface,wear debris analysis, subsurface hardness measurement... The mechanisms of solid particle erosion of several pure metals and steels at low impact angle were studied comprehensively by SEM observations of the worn surface,wear debris analysis, subsurface hardness measurements,incremental erosion tests and sequential erosion study techniques. It was found that at the beginning of erosion,craters and lips were formed on the surfaces of ductile metals due to the deformation caused by the impacting of the particles. The deformed lips were then forged back and forth again and again in erosion process. As a result , small chips of deformed lips were stripped off continuously in the process. All of the evidences show that the erosion mechanisms are encompassed mainly by the process of plastic deformation,lip formation and spelling with ductile metals,while microcutting is more easy to occur with hardened steels. 展开更多
关键词 erosion impact angle ductile steel hardened steel
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Analysis of the financial crisis after the era of Chinese-style shadow banking and regulatory proposals
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作者 Yun Zhao 《International Journal of Technology Management》 2013年第9期128-130,共3页
In 2007, the U.S. subprime crisis -induced global financial crisis swept across the world rapidly, triggering a reflection of Governments on financial regulatory philosophy and systems, it also brought the shadow bank... In 2007, the U.S. subprime crisis -induced global financial crisis swept across the world rapidly, triggering a reflection of Governments on financial regulatory philosophy and systems, it also brought the shadow banking finance in front of the majority of people, it has become the focus of attention. Various management measures have been taken around the shadow banking, and it has brought great volatility to currency and financial markets, and it also highlights the plight of Chinese shadow banking supervision. Therefore, this article briefly analyzes the mechanism of the Financial Times in the Chinese style shadow banking, and makes several regulatory proposals, avoiding low risk of shadow banking at the greatest degree. 展开更多
关键词 financial crisis era shadow banking CAUSES risk.
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The Maghrebian Scholarship and the Development of Muslim Intelligentsias in Sub-Saharan Africa: A Case Study of the Central Bilad al-Sudan
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作者 Mukhtar Umar Bunza 《History Research》 2013年第5期342-352,共11页
Central Bilad al-Sudan refers to the areas of the ancient Hausa states, and the domains of the ancient Kanem Bornu. As a result of the aged long commercial, cultural, and religious linkages between North Africa and th... Central Bilad al-Sudan refers to the areas of the ancient Hausa states, and the domains of the ancient Kanem Bornu. As a result of the aged long commercial, cultural, and religious linkages between North Africa and the Central Sudan, one finds so many things in common among the two regions in dress, diets, cultural traits, as well as educational and religious practices. The extent of influence of the North African region on the individual and communal lives of the central Sudan has been extraordinarily great. The central Sudan is one of the most Islamized areas of West Africa, and Arabic language is second language to the Muslim communities in domestic and public spheres. And as a result of the entrenchment of Islam among the people due to the activities of North African scholars and traders the area became the hub of Islamic scholarship. The intellectual history of the Central Bilad al-Sudan cannot be complete without the mention of an Algerian scholar, Muhammad ibn Abd-A1-Kareem al-Maghili who in addition to his scholarly influence took appointment as Special Adviser in Kano in the 1460s. The same could be said of an Egyptian prolific writer, Jalal al-Deen al-Suyuti, who settled in Katsina and Gobir and also took the appointment of Grand Qadi in Katsina in the 15th century. Similarly, books of Sanhaja scholars, Shinqit Ulama'a, as well as Spanish-Andalusian scholars via Morocco were made available and widely studied in this part of Muslim world. The combination of the activities of such scholars, literature, and learning tradition were responsible lbr the growth and development of Muslim intelligentsia in the central Bilad al-Sudan since the earliest time, and the influence continues to date. Thus this paper aims at examining the phenomenon, primarily by assessing the influence of scholars, literature, and educational institutions from the Maghreb on the intellectual development and the emergence of native scholars and intelligentsia and on the general scholarly trend in the central Bilad al-Sudan. 展开更多
关键词 the Maghreb scholarship central Sudan Northern Nigeria indigenous intelligentsia
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Hydrogen emission at grain boundaries in tensile-deformed Al-9%Mg alloy by hydrogen microprint technique
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作者 Ryoto KOYAMA Goroh ITOH 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第7期2102-2106,共5页
In recently years, environmental problems, such as global warming and exhaustion of fossil fuels, have grown into serious problems. In the automakers, the development of the fuel cell vehicles using hydrogen as clean ... In recently years, environmental problems, such as global warming and exhaustion of fossil fuels, have grown into serious problems. In the automakers, the development of the fuel cell vehicles using hydrogen as clean energy has been paid attention to. Aluminum alloys have already been applied to a liner material of a high-pressure hydrogen tank for fuel cell vehicles. However, the behavior of hydrogen in aluminum alloys has not been clearly elucidated yet. Therefore, it is necessary to analyze the hydrogen behavior in aluminum alloys. Hydrogen microprint technique (HMPT) has been known as an effective measure to investigate the hydrogen behavior. In the present study, the emission behavior of internal hydrogen on a tensile-deformed Al-9%Mg alloy was investigated bv HMPT at room temoerature. As a result, the hydrogen was emitted at some grain boundaries. 展开更多
关键词 aluminum-magnesium alloy internal hydrogen hydrogen microprint technique grain boundary
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Influence of welding speed on corrosion behaviour of friction stir welded AA5086 aluminium alloy 被引量:5
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作者 Kamran Amini Farhad Gharavi 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第6期1301-1311,共11页
The plates of AA5086 aluminium alloy were joined together by friction stir welding at a fixed rotation speed of 1000 r/min various welding speeds ranging from 63 to 100 mm/min.Corrosion behavior of the parent alloy(PA... The plates of AA5086 aluminium alloy were joined together by friction stir welding at a fixed rotation speed of 1000 r/min various welding speeds ranging from 63 to 100 mm/min.Corrosion behavior of the parent alloy(PA),the heat affected zone(HAZ),and the weld nugget zone(WNZ)of the joints were studied in 3.5%(mass fraction)aerated aqueous Na Cl solution by potentiodynamic polarization and electrochemical impedance spectroscopy(EIS).The corrosion susceptibility of the weldments increases when the welding speed increases to 63 and 100 mm/min.However,the value of corrosion rate in the weldments is lower than that in the PA.Additionally,the corrosion current density increases with increasing the welding speed in the HAZ and the WNZ.On the contrary,the corrosion potential in the WNZ appears more positive than in the HAZ with decreasing the welding speed.The WNZ exhibits higher resistance compared to the HAZ and the PA as the welding speed decreases.The results obtained from the EIS measurements suggest that the weld regions have higher corrosion resistance than the parent alloy.With increasing the welding speed,the distribution and extent of the corroded areas in the WNZ region are lower than those of the HAZ region.In the HAZ region,in addition to the pits in the corroded area,some cracks can be seen around the corroded areas,which confirms that intergranular corrosion is formed in this area.The alkaline localized corrosion and the pitting corrosion are the main corrosion mechanisms in the corroded areas within the weld regions.Crystallographic pits are observed within the weld regions. 展开更多
关键词 friction stir welding aluminum alloy corrosion properties welding speed
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