Background: Tuberculosis is endemic in Sudan and has witnessed a major surge amid the country’s continuous conflict. The goal of this study is to analyze the epidemiological aspects of tuberculosis in Western Sudan f...Background: Tuberculosis is endemic in Sudan and has witnessed a major surge amid the country’s continuous conflict. The goal of this study is to analyze the epidemiological aspects of tuberculosis in Western Sudan from 2023 to 2024, during the Sudan War. Methodology: This is a retrospective descriptive study that was carried out at El-Obeid Teaching Hospital in North Kordofan State, Sudan, during August and September 2024. All information on tuberculosis patients diagnosed between 15 April 2023, and 15 April 2024, was obtained from the hospital. Results: The results showed that 71% of the 751 tuberculosis patients had pulmonary tuberculosis, while 29% had extrapulmonary tuberculosis. Among the 533 patients with pulmonary tuberculosis, 74.3% were male and 62% were female. Among the 218 patients with extrapulmonary tuberculosis, 19% were males and 37.9% were females. The predominant age group for pulmonary tuberculosis was 19 - 25 years, followed by ≥46 and 26 - 35 years, with incidence rates of 25.3%, 25%, and 24.6%, respectively. Extrapulmonary tuberculosis was most prevalent in those aged ≥ 46 years, followed by those aged ≤ 18 years and 26 - 35 years, representing 38%, 18.3%, and 16%, respectively. Conclusion: Tuberculosis is prevalent in western Sudan and has seen a significant rise during the region’s conflict. Tuberculosis predominantly impacts individuals in their younger years. The heightened operations of conventional gold mining, coupled with the escalating urban air pollution, have markedly influenced the elevated epidemiological rates of the disease in Sudan. A significant number of individuals receive diagnoses and treatment at a delayed stage, potentially facilitating the propagation of infection.展开更多
Mixed ionic-electronic conductors(MIECs)play a crucial role in the landscape of energy conversion and storage technologies,with a pronounced focus on electrode materials’application in solid oxide fuel cells(SOFCs)an...Mixed ionic-electronic conductors(MIECs)play a crucial role in the landscape of energy conversion and storage technologies,with a pronounced focus on electrode materials’application in solid oxide fuel cells(SOFCs)and proton-conducting ceramic fuel cells(PCFCs).In parallel,the emergence of semiconductor ionic materials(SIMs)has introduced a new paradigm in the field of functional materials,particularly for both electrode and electrolyte development for low-temperature,300–550℃,SOFCs,and PCFCs.This review article critically delves into the intricate mechanisms underpinning the synergistic relationship between MIECs and SIMs,with a particular emphasis on elucidating the fundamental working principles of semiconductor ionic membrane fuel cells(SIMFCs).By exploring critical facets such as ion-coupled electron transfer/transport,junction effect,energy bands alignment,and theoretical computations,it casts an illuminating spotlight on the transformative potential of MIECs,also involving triple charge conducting oxides(TCOs)in the context of SIMs and advanced fuel cells(FCs).The insights and findings articulated herein contribute substantially to the advancement of SIMs and SIMFCs by tailoring MIECs(TCOs)as promising avenues toward the emergence of high-performance SIMFCs.This scientific quest not only addresses the insistent challenges surrounding efficient charge transfer,ionic transport and power output but also unlocks the profound potential for the widespread commercialization of FC technology.展开更多
Manipulating the directional movement of liquid droplets is of significance for design and fabrication of some microfluidic devices, An energy-based method is adopted to analyse the directional movement of a droplet d...Manipulating the directional movement of liquid droplets is of significance for design and fabrication of some microfluidic devices, An energy-based method is adopted to analyse the directional movement of a droplet deposited in a conical tube or on a conical fibre. We perform an experiment to investigate the directional motion of a droplet in an open conical tube. Our theoretical analysis and experimental observations both demonstrate that surface tension can drive the droplet to move in the conical tube. The critical condition of the liquid moving in the conical tube is presented. We also analyse a droplet on a conical hydrophilic fibre, which can move from the thinner to the thicker end.展开更多
Using the concept of the base forces, a new finite element method （base force element method, BFEM） based on the complementary energy principle is presented for accurate modeling of structures with large displacemen...Using the concept of the base forces, a new finite element method （base force element method, BFEM） based on the complementary energy principle is presented for accurate modeling of structures with large displacements and large rotations. First, the complementary energy of an element is described by taking the base forces as state variables, and is then separated into deformation and rotation parts for the case of large deformation. Second, the control equations of the BFEM based on the complementary energy principle are derived using the Lagrange multiplier method. Nonlinear procedure of the BFEM is then developed. Finally, several examples are analyzed to illustrate the reliability and accuracy of the BFEM.展开更多
This paper investigates shear horizontal （SH） waves propagating in a periodically layered structure that consists of piezoelectric （PE） layers perfectly bonded with piezomagnetic （PM） layers alternately. The exp...This paper investigates shear horizontal （SH） waves propagating in a periodically layered structure that consists of piezoelectric （PE） layers perfectly bonded with piezomagnetic （PM） layers alternately. The explicit dispersion relations are derived for the two cases when the propagation directions of SH waves are normal to the interface and parallel to the interface, respectively. The asymptotic expressions for dispersion relations are also given when the wave number is extremely small. Numerical results for stop band effect and phase velocity are presented for a periodic system of alternating BaTiO3 and Terfenol-D layers. The influence of volume fraction on stop band effect and dispersion behaviors is discussed and revealed.展开更多
We propose an experimental approach for investigation of the polycrystalline deformation behaviour at a grain scale. The technique is characterized by the joint application of micro material testing systems and the in...We propose an experimental approach for investigation of the polycrystalline deformation behaviour at a grain scale. The technique is characterized by the joint application of micro material testing systems and the intragranular deformation analysis methods, It is attempting to map the deformation evolution at grain scale during the elastic and plastic deformations of polycrystalline specimens.展开更多
Nix and Gao established an important relation between the microindentation hardness and indentation depth. Such a relation has been verified by many microindentation experiments （indentation depths in the micrometer ...Nix and Gao established an important relation between the microindentation hardness and indentation depth. Such a relation has been verified by many microindentation experiments （indentation depths in the micrometer range）, but it does not always hold in nanoindentation experiments （indentation depths approaching the nanometer range）. Indenter tip radius effect has been proposed by Qu et al. and others as possibly the main factor that causes the deviation from Nix and Gao＇s relationship. We have developed an indentation model for micro- and nanoindentation, which accounts for two indenter shapes, a sharp, conical indenter and a conical indenter with a spherical tip. The analysis is based on the conventional theory of mechanism-based strain gradient plasticity established from the Taylor dislocation model to account for the effect of geometrically necessary dislocations. The comparison between numerical result and Feng and Nix＇s experimental data shows that the indenter tip radius effect indeed causes the deviation from Nix-Gao relation, but it seems not be the main factor.展开更多
The plastic load-bearing capacity of ductile composites such as metal matrix composites is studied with an insight into the microstructures. The macroscopic strength of a composite is obtained by combining the homogen...The plastic load-bearing capacity of ductile composites such as metal matrix composites is studied with an insight into the microstructures. The macroscopic strength of a composite is obtained by combining the homogenization theory with static limit analysis, where the temperature parameter method is used to construct the self-equilibrium stress field. An interface failure model is proposed to account for the effects of the interface on the failure of composites. The static limit analysis with the finite-element method is then formulated as a constrained nonlinear programming problem, which is solved by the Sequential Quadratic Programming （SQP） method. Finally, the macroscopic transverse strength of perforated materials, the macroscopic transverse and off-axis strength of fiber-reinforced composites are obtained through numerical calculation. The computational results are in good agreement with the experimental data.展开更多
通过共沉淀法合成了双金属氧化物MnWO_(4)镶嵌生物质衍生碳(MnWO_(4)/BC)纳米复合催化剂,并将其作为对电极(counter electrode,CE)催化剂组装了染料敏化太阳能电池(dye-sensitized solar cell,DSSC),探究了MnWO_(4)/BC在非碘体系中的催...通过共沉淀法合成了双金属氧化物MnWO_(4)镶嵌生物质衍生碳(MnWO_(4)/BC)纳米复合催化剂,并将其作为对电极(counter electrode,CE)催化剂组装了染料敏化太阳能电池(dye-sensitized solar cell,DSSC),探究了MnWO_(4)/BC在非碘体系中的催化性能和光伏性能。结果表明:在铜氧化还原(Cu^(2+)/Cu^(+))电对DSSC中获得的光电能量转换效率(power conversion efficiency,PCE)为3.57%(D35)和1.59%(Y123),高于Pt电极的PCE(3.12%,1.16%);50次连续循环伏安测试表明,MnWO_(4)/BC催化剂具有较好的电化学稳定性。展开更多
Most animals have the ability to adapt, to some extends and in different ways, the variation or disturbance of environment. In our experiments, we forced a silkworm caterpillar to spin two, three or four thin cocoons ...Most animals have the ability to adapt, to some extends and in different ways, the variation or disturbance of environment. In our experiments, we forced a silkworm caterpillar to spin two, three or four thin cocoons by taking it out from the cocoon being constructed. The mechanical properties of these cocoons were studied by static tensile tests and dynamic mechanical thermal analysis. Though external disturbances may cause the decrease in the total weight of silk spun by the silkworm, a gradual enhancement was interestingly found in the mechanical properties of these thin cocoons. Scanning electron microscopy observations of the fractured specimens of the cocoons showed that there exist several different energy dissipation mechanisms occurred simultaneously at macro-, meso-, and micro-scales, yielding a superior capacity of cocoons to adsorb the energy of possible attacks from the outside and to protect efficiently its pupa against damage. Through evolution of millions of years, therefore, the silkworm Bombyx mori seems to have gained the ability to adapt external disturbances and to redesign a new cocoon with optimized protective function when its first cocoon has been damaged for some reasons.展开更多
文摘Background: Tuberculosis is endemic in Sudan and has witnessed a major surge amid the country’s continuous conflict. The goal of this study is to analyze the epidemiological aspects of tuberculosis in Western Sudan from 2023 to 2024, during the Sudan War. Methodology: This is a retrospective descriptive study that was carried out at El-Obeid Teaching Hospital in North Kordofan State, Sudan, during August and September 2024. All information on tuberculosis patients diagnosed between 15 April 2023, and 15 April 2024, was obtained from the hospital. Results: The results showed that 71% of the 751 tuberculosis patients had pulmonary tuberculosis, while 29% had extrapulmonary tuberculosis. Among the 533 patients with pulmonary tuberculosis, 74.3% were male and 62% were female. Among the 218 patients with extrapulmonary tuberculosis, 19% were males and 37.9% were females. The predominant age group for pulmonary tuberculosis was 19 - 25 years, followed by ≥46 and 26 - 35 years, with incidence rates of 25.3%, 25%, and 24.6%, respectively. Extrapulmonary tuberculosis was most prevalent in those aged ≥ 46 years, followed by those aged ≤ 18 years and 26 - 35 years, representing 38%, 18.3%, and 16%, respectively. Conclusion: Tuberculosis is prevalent in western Sudan and has seen a significant rise during the region’s conflict. Tuberculosis predominantly impacts individuals in their younger years. The heightened operations of conventional gold mining, coupled with the escalating urban air pollution, have markedly influenced the elevated epidemiological rates of the disease in Sudan. A significant number of individuals receive diagnoses and treatment at a delayed stage, potentially facilitating the propagation of infection.
基金supported by the Science and Technology Department of Jiangsu Province under Grant(BE2022029)Jiangsu Provincial Innovation and Entrepreneurship Talent Program(JSSCRC2021491)+3 种基金Key Program for International S&T Cooperation Projects of Shaanxi Province(2019KWZ-03)Key Program for Nature Science Foundation of Shaanxi Province(2019JZ-20)Key Science and Technology Innovation Team of Shaanxi Province(2022TD-34)the Beijing Natural Science Foundation under Grant(IS23050)is greatly acknowledged.
文摘Mixed ionic-electronic conductors(MIECs)play a crucial role in the landscape of energy conversion and storage technologies,with a pronounced focus on electrode materials’application in solid oxide fuel cells(SOFCs)and proton-conducting ceramic fuel cells(PCFCs).In parallel,the emergence of semiconductor ionic materials(SIMs)has introduced a new paradigm in the field of functional materials,particularly for both electrode and electrolyte development for low-temperature,300–550℃,SOFCs,and PCFCs.This review article critically delves into the intricate mechanisms underpinning the synergistic relationship between MIECs and SIMs,with a particular emphasis on elucidating the fundamental working principles of semiconductor ionic membrane fuel cells(SIMFCs).By exploring critical facets such as ion-coupled electron transfer/transport,junction effect,energy bands alignment,and theoretical computations,it casts an illuminating spotlight on the transformative potential of MIECs,also involving triple charge conducting oxides(TCOs)in the context of SIMs and advanced fuel cells(FCs).The insights and findings articulated herein contribute substantially to the advancement of SIMs and SIMFCs by tailoring MIECs(TCOs)as promising avenues toward the emergence of high-performance SIMFCs.This scientific quest not only addresses the insistent challenges surrounding efficient charge transfer,ionic transport and power output but also unlocks the profound potential for the widespread commercialization of FC technology.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10732050, 10525210 and 10121202
文摘Manipulating the directional movement of liquid droplets is of significance for design and fabrication of some microfluidic devices, An energy-based method is adopted to analyse the directional movement of a droplet deposited in a conical tube or on a conical fibre. We perform an experiment to investigate the directional motion of a droplet in an open conical tube. Our theoretical analysis and experimental observations both demonstrate that surface tension can drive the droplet to move in the conical tube. The critical condition of the liquid moving in the conical tube is presented. We also analyse a droplet on a conical hydrophilic fibre, which can move from the thinner to the thicker end.
基金supported by the China Postdoctoral Science Foundation Funded Project (20080430038) the Funding Project for Academic Human Resources Development in Institutions of Higher Learning Under the Jurisdiction of Beijing Municipality (05004999200602)
文摘Using the concept of the base forces, a new finite element method （base force element method, BFEM） based on the complementary energy principle is presented for accurate modeling of structures with large displacements and large rotations. First, the complementary energy of an element is described by taking the base forces as state variables, and is then separated into deformation and rotation parts for the case of large deformation. Second, the control equations of the BFEM based on the complementary energy principle are derived using the Lagrange multiplier method. Nonlinear procedure of the BFEM is then developed. Finally, several examples are analyzed to illustrate the reliability and accuracy of the BFEM.
基金supported by the National Natural Science Foundation of China (Nos.10672108,10572069 and 10820101048)
文摘This paper investigates shear horizontal （SH） waves propagating in a periodically layered structure that consists of piezoelectric （PE） layers perfectly bonded with piezomagnetic （PM） layers alternately. The explicit dispersion relations are derived for the two cases when the propagation directions of SH waves are normal to the interface and parallel to the interface, respectively. The asymptotic expressions for dispersion relations are also given when the wave number is extremely small. Numerical results for stop band effect and phase velocity are presented for a periodic system of alternating BaTiO3 and Terfenol-D layers. The influence of volume fraction on stop band effect and dispersion behaviors is discussed and revealed.
基金Supported by National Natural Science Foundation of China under Grant Nos 10072031, 10372049 and 10232030, the National Basic Research and Development Programme of China Grant No 2004CB619304, and the Central Laboratory of Strength and Vibration of Tsinghua University.
文摘We propose an experimental approach for investigation of the polycrystalline deformation behaviour at a grain scale. The technique is characterized by the joint application of micro material testing systems and the intragranular deformation analysis methods, It is attempting to map the deformation evolution at grain scale during the elastic and plastic deformations of polycrystalline specimens.
基金The project supported by the National Natural Science Foundation of China (10121202)the Ministry of Education of China (20020003023)
文摘Nix and Gao established an important relation between the microindentation hardness and indentation depth. Such a relation has been verified by many microindentation experiments （indentation depths in the micrometer range）, but it does not always hold in nanoindentation experiments （indentation depths approaching the nanometer range）. Indenter tip radius effect has been proposed by Qu et al. and others as possibly the main factor that causes the deviation from Nix and Gao＇s relationship. We have developed an indentation model for micro- and nanoindentation, which accounts for two indenter shapes, a sharp, conical indenter and a conical indenter with a spherical tip. The analysis is based on the conventional theory of mechanism-based strain gradient plasticity established from the Taylor dislocation model to account for the effect of geometrically necessary dislocations. The comparison between numerical result and Feng and Nix＇s experimental data shows that the indenter tip radius effect indeed causes the deviation from Nix-Gao relation, but it seems not be the main factor.
基金Project supported by the Key Grant Project of Chinese Ministry of Education (No.0306)the National Foundationfor Excellent Doctoral Dissertation of China (No.200025).
文摘The plastic load-bearing capacity of ductile composites such as metal matrix composites is studied with an insight into the microstructures. The macroscopic strength of a composite is obtained by combining the homogenization theory with static limit analysis, where the temperature parameter method is used to construct the self-equilibrium stress field. An interface failure model is proposed to account for the effects of the interface on the failure of composites. The static limit analysis with the finite-element method is then formulated as a constrained nonlinear programming problem, which is solved by the Sequential Quadratic Programming （SQP） method. Finally, the macroscopic transverse strength of perforated materials, the macroscopic transverse and off-axis strength of fiber-reinforced composites are obtained through numerical calculation. The computational results are in good agreement with the experimental data.
基金the National Natural Science Foundation of China (10402017,10732050,10525210,10121202)
文摘Most animals have the ability to adapt, to some extends and in different ways, the variation or disturbance of environment. In our experiments, we forced a silkworm caterpillar to spin two, three or four thin cocoons by taking it out from the cocoon being constructed. The mechanical properties of these cocoons were studied by static tensile tests and dynamic mechanical thermal analysis. Though external disturbances may cause the decrease in the total weight of silk spun by the silkworm, a gradual enhancement was interestingly found in the mechanical properties of these thin cocoons. Scanning electron microscopy observations of the fractured specimens of the cocoons showed that there exist several different energy dissipation mechanisms occurred simultaneously at macro-, meso-, and micro-scales, yielding a superior capacity of cocoons to adsorb the energy of possible attacks from the outside and to protect efficiently its pupa against damage. Through evolution of millions of years, therefore, the silkworm Bombyx mori seems to have gained the ability to adapt external disturbances and to redesign a new cocoon with optimized protective function when its first cocoon has been damaged for some reasons.
