It is shown from both the numerical calculation and experimental research in flow ducts with an absorbing wedge at ekit that there does exist considerable noise reduction using single bypass added to the main duct, bu...It is shown from both the numerical calculation and experimental research in flow ducts with an absorbing wedge at ekit that there does exist considerable noise reduction using single bypass added to the main duct, but the amount and spectrum of noise reduction sometimes are not satisfactory in practice. Furthermore, the exit of practical duct is always connected with atmosphere directly so there is not any absorbing wedge at exit. In order to resolve these two problems, a method for predicting the noise reduction in practical ducts using multiple bypasses and numerical samples are presellted in the paper. It is proved correct by a site test, and there is noise reduction of 5 dB(A), even though the site test is not under the optimum situation.展开更多
In this paper, an algorithm for simulating fluid flow and heat transfer for mold filling of shaped castings is presented. The main features of the algorithm include: 1) a simple but practical technique based on VOF me...In this paper, an algorithm for simulating fluid flow and heat transfer for mold filling of shaped castings is presented. The main features of the algorithm include: 1) a simple but practical technique based on VOF method to determine free surface, 2) an explicit scheme of enthalpy to solve the energy equation more efficiently, and 3) an effective treatment to modify the flux deviation due to pressure iteration. In order to verify these methods, well controlled experiments have been repeatedly done with both water analog and gray iron pouring experiments to record the flow patterns and temperature variations. The calculated results are in accordance with the experimental ones. For the applications, the simulated initial temperature distribution right after mold filling was used to analyse subsequent solidification and to predict shrinkage defects. Actual castings were poured and tested in a foundry plant. The reuslts show that the defects predication with considering fluid flow effects is more precise than that without considering the effects.展开更多
Based on the working of Lighthill and Hunt et al., in the present paper the author has established the topological rules adapting to analysing the skin-friction lines and the section streamlines in cascades. These rul...Based on the working of Lighthill and Hunt et al., in the present paper the author has established the topological rules adapting to analysing the skin-friction lines and the section streamlines in cascades. These rules are (1) for a rotor cascade without shroud band, the total number of nodal points equals that the saddle points on the skin-friction line vector fields in eachpitch range; (2) for an annular or straight cascade with no-clearances at blade ends, the total number of saddle points is two more than that of nodal points on the skin-friction line fields in a pitch; (3) the total number of saddles in the secondary flow fields on cross-sections in cascade is one less than that of nodes; (4) in the section streamline vector fields on a meridian surface penetrating a flow passage, and on leading and trailing edge sections, the total number of nodes is equal to that of saddles; (5) on the streamline vector fields of a blade-to-blade surface, the total number of nodes is one less than that of saddles.展开更多
Ⅰ. Introduction Over the past two decades, microwave remote sensing has evolved into a focal point in the remote sensing area. This is due to the fact that in microwave band, we can acquire physical parameters about ...Ⅰ. Introduction Over the past two decades, microwave remote sensing has evolved into a focal point in the remote sensing area. This is due to the fact that in microwave band, we can acquire physical parameters about ocean, terrain and atmosphere on all weather condition. Research and application work about the aerial passive micro wave remote sensors has been done at Changchun Institute of Geography since 1973, under the unitary planning of Academia Sinica. Microwave radiometers of six freqency bands have been developed. Numerous remote sensing experiments were carried out, and large amount of scientific data were accumulated. Recently, theoretical models have展开更多
1 Geological Background of Minerlization or Geologic Setting The northeast of Yunnan1 Pb-Zn-Ag-Ge polymetallic ore district is an important part of the southwestern margin of the Yangtze block Sichuan-Yunnan-Guizhou
Systematic experimental studies on partial melting and subsolidus equilibration of three reconstituted spinel-peridotites have been carried out at temperatures ranging from 1000 to 1380℃ and pressures of 1.0 and 1.5 ...Systematic experimental studies on partial melting and subsolidus equilibration of three reconstituted spinel-peridotites have been carried out at temperatures ranging from 1000 to 1380℃ and pressures of 1.0 and 1.5 GPa. The results shows (1) during partial melting, Mg# [=Mg/(Mg+Fe)]and Cr# [=Cr/(Cr-Al)]of spinel increase with an increase in degrees of melting) (2) during subsolidus equilibration, with increasing temperatures, Mg# of spinel increases but Cr# of spinel remains almost unchanged in dunite and increases slightly in Iherzolite and harzburgite. The negative and quasi-linear Mg# -Cr# correlation of spinel represents an isotherm of total non-equilibrium. The same results have been obtained by means of mathematical modelling. It is also proved by Mg# -Cr# correlation of spinel in natural peridotites. As a result of the spinel subsolidus equilibration, only variation of Cr# of spinel is limited, and then Cr# of spinel can be used to estimate the relative degree of melting undergone by host rocks. The bigger Cr# of spinel is, the higher the degree of melting will be. By contrast, during crystallization magma, Mg# and Cr# of spinel decrease with decreasing temperatures. Likewise, Cr# of spinel in basalts may be used to indicate the feature of Cr2O3/Al2O3 of magma, and the compositional zoning of spinel may be used to study the evolution of magma (cooling rate and contamination).展开更多
The modified shear lag model proposed recently was applied to calculate thermal residual stresses and subsequent stress distributions under tensile and compressive loadings. The expressions for the elastic moduli and ...The modified shear lag model proposed recently was applied to calculate thermal residual stresses and subsequent stress distributions under tensile and compressive loadings. The expressions for the elastic moduli and the yield strengths under tensile and compressive loadings were derived which take account of thermal residual stresses. The asymmetries in the elastic modulus and the yield strength were interpreted using the derived expressions and the obtained results of the stress calculations. The model predictions have exhibited good agreements with the experimental results and also with the other theoretical predictions展开更多
A new highly sensitive spectrophotometric method has been developed for the determination of micro amounts of bismuth (Ⅲ), based on the formation of Bi (Ⅲ)—meso—tetrakis—(4—N—trimethylammonium phenyl) porphine ...A new highly sensitive spectrophotometric method has been developed for the determination of micro amounts of bismuth (Ⅲ), based on the formation of Bi (Ⅲ)—meso—tetrakis—(4—N—trimethylammonium phenyl) porphine [T (4TMAP) P] complex. In the presence of Cd (Ⅱ), Bi(Ⅲ) reacts almost instantaneously with T (4TMAP)P in a 0. 6 mol/l NaAc—HAC buffer (PH5.8) at room temperature. The composition of the complex is T(4TMAP)P: Bi=1:1. The absorbance complex obeys Beer's law over the Bi(Ⅲ) concentration range 0.1—1.4 μg/ml. The linear relative coefficient γ is 0.9998. The apparent molar absorptivity was 1.75×10~5 1. mol^(-1). cm^(-1) at 463nm. The relative standard deviation of the method is 1.50％ for Bi(Ⅲ) 7ug/10ml (10 determinations). The interference of foreign ions has been examined. This simple and rapid method can be applied to the assay of Bi(Ⅲ) in some tablets directly.展开更多
In the media of 0.66,0.96, 2. 16 and 0.54 mol/L ofH2SO4,the heteropoly acids of As,P.Si and Ge are separately reduced to corresponding heteropoly blues by gibberellin, which exhibit maxirnum absorptions at 835, 820, 8...In the media of 0.66,0.96, 2. 16 and 0.54 mol/L ofH2SO4,the heteropoly acids of As,P.Si and Ge are separately reduced to corresponding heteropoly blues by gibberellin, which exhibit maxirnum absorptions at 835, 820, 810 and 805 nm with molar absorptivities of 2.64x104, 2.54x104 3.51x104 and 2.25x104 L.mol-1'cm-1 and linear ranges of 0-30,0-15,0-10 and 0-30 μg/25mL, The method was applied to the determinations of As, P and Si in alloyed steel.展开更多
The electroanalytical behaviour of xanthophyll was studied by differential pulse polarography and cyclic voltammetry.The reduction wave of xanthophyll at -0.92V(v.s.Ag/AgCl)in 1.25% tetrabutyl ammonium chloride soluti...The electroanalytical behaviour of xanthophyll was studied by differential pulse polarography and cyclic voltammetry.The reduction wave of xanthophyll at -0.92V(v.s.Ag/AgCl)in 1.25% tetrabutyl ammonium chloride solution(TBAC)was found for the first time.The optimum conditions for the determination of xanthophyll by DPP were established. The results from the application of cyclic voltammetry to study electrode process behaviour showed that the electrode reaction of xanthophyll at a hanging mercury electrode is quasi-reversible reaction.展开更多
For the first time,fullerenes are applied to the study on the interface between two immisible electrolyte solutions.Experiments show they are a new kind of inhibitors. Obvious inhibitive behavior to the TMA^+ transfer...For the first time,fullerenes are applied to the study on the interface between two immisible electrolyte solutions.Experiments show they are a new kind of inhibitors. Obvious inhibitive behavior to the TMA^+ transfer across the water/nitrobenzene interface is observed.展开更多
The present paper reports a novel chemiluminescence,i.e,isopropyl alcohol-C10^--H_2O_2 system.The chemiluminescence intensity is proportional to the concentration of C10^- within certain range.Based on this fact,a new...The present paper reports a novel chemiluminescence,i.e,isopropyl alcohol-C10^--H_2O_2 system.The chemiluminescence intensity is proportional to the concentration of C10^- within certain range.Based on this fact,a new chemiluminescence method for the determination of micro amount of C10^- has been developed.The detection limit is 2.6 x 10^(-8)g/ml C10^- and the dynamic linear range is 2.6 x 10^(-8)g/ml to 2.3 x 10^(-5)g/ml C10^-.The method has good selectivlty and reproducibility.展开更多
1.China’s Human Genome DevelopmentThe international programe--sequencingof human genome, honored as the "MoonLanding Program" started in 1990, havingmany scientists from the United States,Japan, Germany, Fr...1.China’s Human Genome DevelopmentThe international programe--sequencingof human genome, honored as the "MoonLanding Program" started in 1990, havingmany scientists from the United States,Japan, Germany, France and展开更多
Under steady-state conditions, the general currents of EE reactions at disk,hemispherical and spherical microelectrodes are derived.From these equations, some electrode reaction parameters can be very simply obtained.
Objective Nowadays, high-resolution remote sensing technology has brought new changes to surveys of earthquakes, and the quantitative study of seismic faults based on this technology has become a trend in the world(Ba...Objective Nowadays, high-resolution remote sensing technology has brought new changes to surveys of earthquakes, and the quantitative study of seismic faults based on this technology has become a trend in the world(Barzegari et al., 2017). An Mw 7.2 earthquake occurred in Yutian of Xinjiang on the western end of the Altyn Tagh fault on March 21 st, 2008. It is difficult to access this depopulated zone because of the high altitude and only 1–2 months of snowmelt. This study utilized high-resolution展开更多
Nanotechnology (NT) deals with materials from 1 to 100 nm in length. Internationaly, NT is defined as the understanding, manipulation, and control of matter at the length mentioned above, thus, the physical, chemical,...Nanotechnology (NT) deals with materials from 1 to 100 nm in length. Internationaly, NT is defined as the understanding, manipulation, and control of matter at the length mentioned above, thus, the physical, chemical, and biological properties of the materials (individual atoms, molecules, and bulk matter) can be engineered, synthesized, and altered to develop the next generation of improved materials, devices, structures, and systems. NT at the molecular level can be used to develop desired textile with special feature, such as high strength, unique surface structure, soft feeling, durability, water resistance, incombustibility, antimicrobial property, and so on. Indeed, NT has created numerous opportunities and challenges in the need of research, by the advancing of the technology in textile industry of China and the importing of bamboo charcoal fibers of nanotechnology from foreign countries. This paper focuses on summarizing recent applications of NT, its characters and functional test for bamboo charcoal fibers.展开更多
The urban thermal distribution characteristics and its variation are dynamically monitored and synthetically analyzed by using GIS technology. The meteorological satellite data serve as main information source, assist...The urban thermal distribution characteristics and its variation are dynamically monitored and synthetically analyzed by using GIS technology. The meteorological satellite data serve as main information source, assisted as auxiliary information sources by the landsat satellite TM data, land use thematic maps and meteorological observed data. A correlated pattern on the ground surface brightness temperatures and air temperatures has been studied and established with good performance of application.展开更多
In the present study, bond-coats for thermal barrier coatings were deposited via air plasma spraying（APS） techniques onto Inconel 800 and Hastelloy C-276 alloy substrates. Scanning electron microscopy（SEM）, transm...In the present study, bond-coats for thermal barrier coatings were deposited via air plasma spraying（APS） techniques onto Inconel 800 and Hastelloy C-276 alloy substrates. Scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, X-ray diffraction（XRD）, and atomic force microscopy（AFM） were used to investigate the phases and microstructure of the as-sprayed, APS-deposited Co Ni Cr Al Y bond-coatings. The aim of this work was to study the suitability of the bond-coat materials for high temperature applications. Confirmation of nanoscale grains of the γ/γ′-phase was obtained by TEM, high-resolution TEM, and AFM. We concluded that these changes result from the plastic deformation of the bond-coat during the deposition, resulting in Co Ni Cr Al Y bond-coatings with excellent thermal cyclic resistance suitable for use in high-temperature applications. Cyclic oxidative stability was observed to also depend on the underlying metallic alloy substrate.展开更多
Purpose: The authors analyzed the epidemiological and clinical aspects of diabetic retinopathy at the Center for the Application of the Specialized Studies Diploma in Ophthalmology, Gamal Abdel Nasser University (CHU/...Purpose: The authors analyzed the epidemiological and clinical aspects of diabetic retinopathy at the Center for the Application of the Specialized Studies Diploma in Ophthalmology, Gamal Abdel Nasser University (CHU/ Donka) Conakry. Diabetic retinopathy (eye damage: eye and retina) is a serious complication of diabetes that affects 50% of type 2 diabetic patients. The eyes are particularly sensitive to damage to a small vessel. Diabetic retinopathy (DR) is the retinal localization of diabetic micro angiopathy resulting in impaired blood flow in the affected territories, the consequences of which will determine the clinical manifestations of the disease. DR is the leading cause of vision loss in adults of working age. Patients and Methods: This is a longitudinal prospective study carried out at CADES/O concerning 198 diabetic patients. The selection criteria were that the media be transparent and the fundus accessible over a period of six months from February to July 2018. Results: A total of 73 patients (37%) presented with diabetic retinopathy with an average age of 49.5 +/−9 years. The sex ratio (M/F) was 0.6 with a female predominance of 59%. Liberal profession patients were the most numerous 47.5%. Type 2 diabetes was the most common (85.86%). Diabetes fundus assessment was the most common reason for consultation (52%). Arterial hypertension was the most incriminated risk factor (45.45%) followed by the poor balance of diabetes (40.90%), and the age of diabetes (28.28%). 9.5% had diabetic retinopathy complicated by rubella iris, neovascular glaucoma and retinal detachment. Conclusion: Diabetic retinopathy is a common condition for which early detection and regular monitoring must be the rule to prevent, slow down or avoids irreversible blindness if possible, induced by this pathology by a good balance of diabetes and good control of associated risk factors.展开更多
文摘It is shown from both the numerical calculation and experimental research in flow ducts with an absorbing wedge at ekit that there does exist considerable noise reduction using single bypass added to the main duct, but the amount and spectrum of noise reduction sometimes are not satisfactory in practice. Furthermore, the exit of practical duct is always connected with atmosphere directly so there is not any absorbing wedge at exit. In order to resolve these two problems, a method for predicting the noise reduction in practical ducts using multiple bypasses and numerical samples are presellted in the paper. It is proved correct by a site test, and there is noise reduction of 5 dB(A), even though the site test is not under the optimum situation.
文摘In this paper, an algorithm for simulating fluid flow and heat transfer for mold filling of shaped castings is presented. The main features of the algorithm include: 1) a simple but practical technique based on VOF method to determine free surface, 2) an explicit scheme of enthalpy to solve the energy equation more efficiently, and 3) an effective treatment to modify the flux deviation due to pressure iteration. In order to verify these methods, well controlled experiments have been repeatedly done with both water analog and gray iron pouring experiments to record the flow patterns and temperature variations. The calculated results are in accordance with the experimental ones. For the applications, the simulated initial temperature distribution right after mold filling was used to analyse subsequent solidification and to predict shrinkage defects. Actual castings were poured and tested in a foundry plant. The reuslts show that the defects predication with considering fluid flow effects is more precise than that without considering the effects.
文摘Based on the working of Lighthill and Hunt et al., in the present paper the author has established the topological rules adapting to analysing the skin-friction lines and the section streamlines in cascades. These rules are (1) for a rotor cascade without shroud band, the total number of nodal points equals that the saddle points on the skin-friction line vector fields in eachpitch range; (2) for an annular or straight cascade with no-clearances at blade ends, the total number of saddle points is two more than that of nodal points on the skin-friction line fields in a pitch; (3) the total number of saddles in the secondary flow fields on cross-sections in cascade is one less than that of nodes; (4) in the section streamline vector fields on a meridian surface penetrating a flow passage, and on leading and trailing edge sections, the total number of nodes is equal to that of saddles; (5) on the streamline vector fields of a blade-to-blade surface, the total number of nodes is one less than that of saddles.
文摘Ⅰ. Introduction Over the past two decades, microwave remote sensing has evolved into a focal point in the remote sensing area. This is due to the fact that in microwave band, we can acquire physical parameters about ocean, terrain and atmosphere on all weather condition. Research and application work about the aerial passive micro wave remote sensors has been done at Changchun Institute of Geography since 1973, under the unitary planning of Academia Sinica. Microwave radiometers of six freqency bands have been developed. Numerous remote sensing experiments were carried out, and large amount of scientific data were accumulated. Recently, theoretical models have
文摘1 Geological Background of Minerlization or Geologic Setting The northeast of Yunnan1 Pb-Zn-Ag-Ge polymetallic ore district is an important part of the southwestern margin of the Yangtze block Sichuan-Yunnan-Guizhou
文摘Systematic experimental studies on partial melting and subsolidus equilibration of three reconstituted spinel-peridotites have been carried out at temperatures ranging from 1000 to 1380℃ and pressures of 1.0 and 1.5 GPa. The results shows (1) during partial melting, Mg# [=Mg/(Mg+Fe)]and Cr# [=Cr/(Cr-Al)]of spinel increase with an increase in degrees of melting) (2) during subsolidus equilibration, with increasing temperatures, Mg# of spinel increases but Cr# of spinel remains almost unchanged in dunite and increases slightly in Iherzolite and harzburgite. The negative and quasi-linear Mg# -Cr# correlation of spinel represents an isotherm of total non-equilibrium. The same results have been obtained by means of mathematical modelling. It is also proved by Mg# -Cr# correlation of spinel in natural peridotites. As a result of the spinel subsolidus equilibration, only variation of Cr# of spinel is limited, and then Cr# of spinel can be used to estimate the relative degree of melting undergone by host rocks. The bigger Cr# of spinel is, the higher the degree of melting will be. By contrast, during crystallization magma, Mg# and Cr# of spinel decrease with decreasing temperatures. Likewise, Cr# of spinel in basalts may be used to indicate the feature of Cr2O3/Al2O3 of magma, and the compositional zoning of spinel may be used to study the evolution of magma (cooling rate and contamination).
文摘The modified shear lag model proposed recently was applied to calculate thermal residual stresses and subsequent stress distributions under tensile and compressive loadings. The expressions for the elastic moduli and the yield strengths under tensile and compressive loadings were derived which take account of thermal residual stresses. The asymmetries in the elastic modulus and the yield strength were interpreted using the derived expressions and the obtained results of the stress calculations. The model predictions have exhibited good agreements with the experimental results and also with the other theoretical predictions
文摘A new highly sensitive spectrophotometric method has been developed for the determination of micro amounts of bismuth (Ⅲ), based on the formation of Bi (Ⅲ)—meso—tetrakis—(4—N—trimethylammonium phenyl) porphine [T (4TMAP) P] complex. In the presence of Cd (Ⅱ), Bi(Ⅲ) reacts almost instantaneously with T (4TMAP)P in a 0. 6 mol/l NaAc—HAC buffer (PH5.8) at room temperature. The composition of the complex is T(4TMAP)P: Bi=1:1. The absorbance complex obeys Beer's law over the Bi(Ⅲ) concentration range 0.1—1.4 μg/ml. The linear relative coefficient γ is 0.9998. The apparent molar absorptivity was 1.75×10~5 1. mol^(-1). cm^(-1) at 463nm. The relative standard deviation of the method is 1.50％ for Bi(Ⅲ) 7ug/10ml (10 determinations). The interference of foreign ions has been examined. This simple and rapid method can be applied to the assay of Bi(Ⅲ) in some tablets directly.
文摘In the media of 0.66,0.96, 2. 16 and 0.54 mol/L ofH2SO4,the heteropoly acids of As,P.Si and Ge are separately reduced to corresponding heteropoly blues by gibberellin, which exhibit maxirnum absorptions at 835, 820, 810 and 805 nm with molar absorptivities of 2.64x104, 2.54x104 3.51x104 and 2.25x104 L.mol-1'cm-1 and linear ranges of 0-30,0-15,0-10 and 0-30 μg/25mL, The method was applied to the determinations of As, P and Si in alloyed steel.
文摘The electroanalytical behaviour of xanthophyll was studied by differential pulse polarography and cyclic voltammetry.The reduction wave of xanthophyll at -0.92V(v.s.Ag/AgCl)in 1.25% tetrabutyl ammonium chloride solution(TBAC)was found for the first time.The optimum conditions for the determination of xanthophyll by DPP were established. The results from the application of cyclic voltammetry to study electrode process behaviour showed that the electrode reaction of xanthophyll at a hanging mercury electrode is quasi-reversible reaction.
文摘For the first time,fullerenes are applied to the study on the interface between two immisible electrolyte solutions.Experiments show they are a new kind of inhibitors. Obvious inhibitive behavior to the TMA^+ transfer across the water/nitrobenzene interface is observed.
文摘The present paper reports a novel chemiluminescence,i.e,isopropyl alcohol-C10^--H_2O_2 system.The chemiluminescence intensity is proportional to the concentration of C10^- within certain range.Based on this fact,a new chemiluminescence method for the determination of micro amount of C10^- has been developed.The detection limit is 2.6 x 10^(-8)g/ml C10^- and the dynamic linear range is 2.6 x 10^(-8)g/ml to 2.3 x 10^(-5)g/ml C10^-.The method has good selectivlty and reproducibility.
文摘1.China’s Human Genome DevelopmentThe international programe--sequencingof human genome, honored as the "MoonLanding Program" started in 1990, havingmany scientists from the United States,Japan, Germany, France and
文摘Under steady-state conditions, the general currents of EE reactions at disk,hemispherical and spherical microelectrodes are derived.From these equations, some electrode reaction parameters can be very simply obtained.
基金supported by the National Natural Science Foundation of China (grants No. 41461164002 and 41631073)
文摘Objective Nowadays, high-resolution remote sensing technology has brought new changes to surveys of earthquakes, and the quantitative study of seismic faults based on this technology has become a trend in the world(Barzegari et al., 2017). An Mw 7.2 earthquake occurred in Yutian of Xinjiang on the western end of the Altyn Tagh fault on March 21 st, 2008. It is difficult to access this depopulated zone because of the high altitude and only 1–2 months of snowmelt. This study utilized high-resolution
文摘Nanotechnology (NT) deals with materials from 1 to 100 nm in length. Internationaly, NT is defined as the understanding, manipulation, and control of matter at the length mentioned above, thus, the physical, chemical, and biological properties of the materials (individual atoms, molecules, and bulk matter) can be engineered, synthesized, and altered to develop the next generation of improved materials, devices, structures, and systems. NT at the molecular level can be used to develop desired textile with special feature, such as high strength, unique surface structure, soft feeling, durability, water resistance, incombustibility, antimicrobial property, and so on. Indeed, NT has created numerous opportunities and challenges in the need of research, by the advancing of the technology in textile industry of China and the importing of bamboo charcoal fibers of nanotechnology from foreign countries. This paper focuses on summarizing recent applications of NT, its characters and functional test for bamboo charcoal fibers.
基金The Key Project of the Ninth Five-Year Plan Period, No. 96-908-05-06
文摘The urban thermal distribution characteristics and its variation are dynamically monitored and synthetically analyzed by using GIS technology. The meteorological satellite data serve as main information source, assisted as auxiliary information sources by the landsat satellite TM data, land use thematic maps and meteorological observed data. A correlated pattern on the ground surface brightness temperatures and air temperatures has been studied and established with good performance of application.
基金provided by Technical Education Quality Improvement Programme-Ⅱ(TEQIP-Ⅱ)at MNNIT Allahabad
文摘In the present study, bond-coats for thermal barrier coatings were deposited via air plasma spraying（APS） techniques onto Inconel 800 and Hastelloy C-276 alloy substrates. Scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, X-ray diffraction（XRD）, and atomic force microscopy（AFM） were used to investigate the phases and microstructure of the as-sprayed, APS-deposited Co Ni Cr Al Y bond-coatings. The aim of this work was to study the suitability of the bond-coat materials for high temperature applications. Confirmation of nanoscale grains of the γ/γ′-phase was obtained by TEM, high-resolution TEM, and AFM. We concluded that these changes result from the plastic deformation of the bond-coat during the deposition, resulting in Co Ni Cr Al Y bond-coatings with excellent thermal cyclic resistance suitable for use in high-temperature applications. Cyclic oxidative stability was observed to also depend on the underlying metallic alloy substrate.
文摘Purpose: The authors analyzed the epidemiological and clinical aspects of diabetic retinopathy at the Center for the Application of the Specialized Studies Diploma in Ophthalmology, Gamal Abdel Nasser University (CHU/ Donka) Conakry. Diabetic retinopathy (eye damage: eye and retina) is a serious complication of diabetes that affects 50% of type 2 diabetic patients. The eyes are particularly sensitive to damage to a small vessel. Diabetic retinopathy (DR) is the retinal localization of diabetic micro angiopathy resulting in impaired blood flow in the affected territories, the consequences of which will determine the clinical manifestations of the disease. DR is the leading cause of vision loss in adults of working age. Patients and Methods: This is a longitudinal prospective study carried out at CADES/O concerning 198 diabetic patients. The selection criteria were that the media be transparent and the fundus accessible over a period of six months from February to July 2018. Results: A total of 73 patients (37%) presented with diabetic retinopathy with an average age of 49.5 +/−9 years. The sex ratio (M/F) was 0.6 with a female predominance of 59%. Liberal profession patients were the most numerous 47.5%. Type 2 diabetes was the most common (85.86%). Diabetes fundus assessment was the most common reason for consultation (52%). Arterial hypertension was the most incriminated risk factor (45.45%) followed by the poor balance of diabetes (40.90%), and the age of diabetes (28.28%). 9.5% had diabetic retinopathy complicated by rubella iris, neovascular glaucoma and retinal detachment. Conclusion: Diabetic retinopathy is a common condition for which early detection and regular monitoring must be the rule to prevent, slow down or avoids irreversible blindness if possible, induced by this pathology by a good balance of diabetes and good control of associated risk factors.
