Cloud storage,a core component of cloud computing,plays a vital role in the storage and management of data.Electronic Health Records(EHRs),which document users’health information,are typically stored on cloud servers...Cloud storage,a core component of cloud computing,plays a vital role in the storage and management of data.Electronic Health Records(EHRs),which document users’health information,are typically stored on cloud servers.However,users’sensitive data would then become unregulated.In the event of data loss,cloud storage providers might conceal the fact that data has been compromised to protect their reputation and mitigate losses.Ensuring the integrity of data stored in the cloud remains a pressing issue that urgently needs to be addressed.In this paper,we propose a data auditing scheme for cloud-based EHRs that incorporates recoverability and batch auditing,alongside a thorough security and performance evaluation.Our scheme builds upon the indistinguishability-based privacy-preserving auditing approach proposed by Zhou et al.We identify that this scheme is insecure and vulnerable to forgery attacks on data storage proofs.To address these vulnerabilities,we enhanced the auditing process using masking techniques and designed new algorithms to strengthen security.We also provide formal proof of the security of the signature algorithm and the auditing scheme.Furthermore,our results show that our scheme effectively protects user privacy and is resilient against malicious attacks.Experimental results indicate that our scheme is not only secure and efficient but also supports batch auditing of cloud data.Specifically,when auditing 10,000 users,batch auditing reduces computational overhead by 101 s compared to normal auditing.展开更多
In the process of stage separation of recoverable liquid launch vehicles,because of the large amount of residual fuel in the storage tanks,the influence of liquid sloshing on separation safety must be considered.Consi...In the process of stage separation of recoverable liquid launch vehicles,because of the large amount of residual fuel in the storage tanks,the influence of liquid sloshing on separation safety must be considered.Considering calculation simplicity and operation practicability,the Moving Pulsating Ball Model(MPBM)of large amplitude liquid sloshing is introduced into the calculation of launch vehicle stage separation.Combining the dynamic equation of the model with the energy relationship during"breathing movement",the formula calculating the force of liquid on the rigid body is derived.Compared with the calculations of commercial CFD calculation software,the accuracy of MPBM model is verified.Then,all the external forces and moments are applied to the rigid body of the stages,so that the translational and rotational dynamic equations of the stages are obtained respectively.According to the relative position of the two stages,the geometric shape of the interstage section and the engine of the second stage,the minimum clearance in the separation process can be decided to guarantee that the separation process is safe.展开更多
Calculation of the groundwater recoverable resource is the main part of groundwater resource evaluation. The three-dimensional groundwater flow model in Linfen Basin was established by GMS software. Then the numerical...Calculation of the groundwater recoverable resource is the main part of groundwater resource evaluation. The three-dimensional groundwater flow model in Linfen Basin was established by GMS software. Then the numerical model was calibrated by observed groundwater level from February to December in 2 000. Based on the calibrated model, the groundwater recoverable resource is calculated. The simulation result shows that under the given value of the groundwater recoverable resource, the groundwater level would decrease significantly in the first 1 000 days, while the water level would drop slowly in 1 000 to 2 000 days, and the water level change tend to be stable after 2000 days.展开更多
As a significant inducement during the development of oil and gas,the role of remaining recoverable reserves is more observable especially in the later phase of development of oilfield.Depended on the production decli...As a significant inducement during the development of oil and gas,the role of remaining recoverable reserves is more observable especially in the later phase of development of oilfield.Depended on the production decline method in petroleum reservoir engineering,a new model of predicting recoverable and remaining recoverable reserves has been展开更多
This paper reviews the recoverable satellites China has developed over the past forty years.The main missions,technical specifications,scientific and technical experiments of these satellites,including the SJ-10 scien...This paper reviews the recoverable satellites China has developed over the past forty years.The main missions,technical specifications,scientific and technical experiments of these satellites,including the SJ-10 scientific experiment satellite launched on April 6,2016 are introduced.Recommendations for future technical upgrades for recoverable satellites are also proposed in the paper.展开更多
Based on experimental study of the time dependence of the recoverable shape memory effect (SME)of shape memory alloys Ti50Ni50,Ti50Ni48Cu2 and Ti50Ni45Cu5 an empirical re- lationship between recoverable strain energy,...Based on experimental study of the time dependence of the recoverable shape memory effect (SME)of shape memory alloys Ti50Ni50,Ti50Ni48Cu2 and Ti50Ni45Cu5 an empirical re- lationship between recoverable strain energy,U_r,and temperature,T.was derived as: U_r=U_o[1-exp(-mT_R^n)] where m—characteristic constant related to material,and n-shape-temperature sensitivity. The Johnson-Mehl-Aerami's phenomenological description of the time dependence of phase transformation was adopted to obtain a semiquantitative relationship associated with recoverable SME.between thermoelastic martensite transformation and temperature.This semiquantitative relationship is correspondent with the empirical expression.展开更多
The ferroelectric superlattices have been widely studied due to their distinguished electromechanical coupling properties.Under different biaxial mismatch strains,ferroelectric superlattices exhibit different domain s...The ferroelectric superlattices have been widely studied due to their distinguished electromechanical coupling properties.Under different biaxial mismatch strains,ferroelectric superlattices exhibit different domain structures and electromechanical coupling properties.A three-dimensional phase field model is employed to investigate the detailed domain evolution and electromechanical properties of the PbTiO_(3)/SrTiO_(3)(PTO/STO)superlattices with different biaxial mismatch strains.The phase field simulations show that the ferroelectric superlattice exhibits large electrostrain in the stacking direction when an external field is applied.Under a large compressive mismatch strain,vortex domains appear in ferroelectric layers with the thickness of 4 nm.The vortex domains become stable cdomain under a large external electric field,which remains when the electric field is removed.When the initial compressive mismatch strain decreases gradually,the waved or a1/a2 domains replaces the initial vortex domains in the absence of electric field.The fully polarized c-domain by a large electric field switches to diagonal direction domain or a/c domain when the electric field is small.Furthermore,when a biaxial tensile strain is applied to the superlattice,ferroelectric domains switch back to the initial a1/a2 twin-like domain structure,resulting in the recoverable and large electrostrain.This provides an effective way to obtain the large and recoverable electrostrain for the engineering application.展开更多
SJ-10 is a recoverable scientific experiment satellite specially for the space experiments of microgravity physics science and space life science.This mission was officially started on 31 December 2012,and the satelli...SJ-10 is a recoverable scientific experiment satellite specially for the space experiments of microgravity physics science and space life science.This mission was officially started on 31 December 2012,and the satellite was launched on 6 April 2016.This paper introduces briefly the SJ-10 mission,the progress of SJ-10 engineering and the project constitution of sciences experiments onboard SJ-10.The purpose of this mission is to discover the law of matter movement and the rule of life activity that cannot be discovered on the ground due to the existence of gravity,and to know the acting mechanism on organisms by the complex radiation of space that cannot be simulated on the ground.展开更多
A new free recoverable and reusable mono-alkaloid-type ligand has been synthesized by a simple method. With highly polar groups, the ligand can be recycled and reused eight times to prepare ethyl （2R,3S）-2,3-dihydro...A new free recoverable and reusable mono-alkaloid-type ligand has been synthesized by a simple method. With highly polar groups, the ligand can be recycled and reused eight times to prepare ethyl （2R,3S）-2,3-dihydroxy-3-phenylpropionate with high yield and ee via asymmetric dihydroxylation （AD） reaction. C 2009 Sheng Yong Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
This paper presents a conceptual framework of integrated waste management which focuses on all stages of product life cycle. A mechanism of resource recovery motivating from waste in economic system （designers, produ...This paper presents a conceptual framework of integrated waste management which focuses on all stages of product life cycle. A mechanism of resource recovery motivating from waste in economic system （designers, producers, consumers, stakeholders in the field of disposal of the product） is suggested. The classification of institutional and economic instruments in the field of waste management as recoverable resources is developed. The author has proposed a scientific and methodical approach to the formation of an integrated waste management as recoverable resources, which is based on a set of methods of economic incentives at all stages of product life cycle and ensures the maximum possible and the environmentally safe management of wastes containing valuable resource components.展开更多
Total recoverable concentration of five elements of concern: Aluminum, Iron, Manganese, Arsenic and Lead (Al, Fe, Mn, As, Pb) were measured by inductively coupled plasma atomic emission spectrometry, and mass spectrom...Total recoverable concentration of five elements of concern: Aluminum, Iron, Manganese, Arsenic and Lead (Al, Fe, Mn, As, Pb) were measured by inductively coupled plasma atomic emission spectrometry, and mass spectrometry. The results show that sediment texture plays a controlling role in the concentrations and their spatial distribution. Principal Component Analysis and Cluster Analysis were used to analyze the grain sizes of the sediments. Result of texture analysis classified the samples into three main components in percentages: sand, silt, and clay. Significant differences among the element concentrations in the three groups were observed, and the concentrations of the elements in each group are reported in this study. Most of the elements have their highest concentrations in the fine-grained samples with clay playing an important role, in comparison with the sand component of the soil/sediment samples. There appears to be a strong correlation between samples with high silt, and clay content with the areas of elevated concentrations for Al, Fe, and Mn. There was a strong correlation between aluminum and lead with clay;lead with silt;and sand with manganese, aluminum, and lead. However, there was no strong relationship between the soil textures and iron or arsenic. All elements measured were statistically significant (at P ≤ 0.05) by watershed. The upland areas, and depositional areas’ spatial variation of element concentrations in the sediments were also observed, which was in line with the spatial distribution of the grain size and was thought to be related to the watersheds hydrological dynamics.展开更多
In order to fulfil the microgravity requirements for space experiments, improved technology for the microgravity environment is proposed, including that for raising the orbital altitude, optimizing the layout of the d...In order to fulfil the microgravity requirements for space experiments, improved technology for the microgravity environment is proposed, including that for raising the orbital altitude, optimizing the layout of the disturbance source, using IN-thrusters instead of 5 N-thrusters, etc. In addition, evaluation of the microgravity environment of the recoverable satellite was also conducted using on-orbit micro-vibration measurement, on-orbit experiment and data analysis technologies. The microgravity level of the SJ-l0 recoverable satellite in China is compared with the spacecraft used for carrying out space science experiments internationally. This paper describes the microgravity environment of the SJ- 10 recoverable satellite, and its importance for analysing space experimental results.展开更多
The paper introduces a kind of full length recoverable resin metal bolts, expounds its structural principle and stress features, and gives some instances in laboratory tests and underground tests. The results show tha...The paper introduces a kind of full length recoverable resin metal bolts, expounds its structural principle and stress features, and gives some instances in laboratory tests and underground tests. The results show that full length recoverable resin metal bolts can be used for supporting the walls of class Ⅰ～Ⅲ mining gateways, that the anchoring force is 50 kN or so, and that the recoverability rate is more than 80%, thus the supporting effect is better than that of split set bolts.展开更多
On August 25,1992,China suc-cessfully returned its 13th recover-able satellite from orbit after 16days’operation.The satellite is thefirst one of the second generation ofthe Chinese recoverable satellites.Itemployed ...On August 25,1992,China suc-cessfully returned its 13th recover-able satellite from orbit after 16days’operation.The satellite is thefirst one of the second generation ofthe Chinese recoverable satellites.Itemployed initially the newly devel-oped LEO control technology.Compared with former recoverablesatellites,its capability was im-proved a lot by using many newtechnologies on satellite structure,on-board detection equipment andsatellite control,etc..展开更多
It remains a challenge to achieve rapidly recoverable hydrogels by molecular hydrogen-bonding interaction because of its slow inter-action kinetics.This work for the first time reports a trehalose(Tre)-based molecular...It remains a challenge to achieve rapidly recoverable hydrogels by molecular hydrogen-bonding interaction because of its slow inter-action kinetics.This work for the first time reports a trehalose(Tre)-based molecular movement mechanism inside a single network of polyacrylamide(PAM)that accelerates the kinetics of hydrogenbonding interaction,and thereby endows the hydrogel with high toughness and rapid shape and mechanical recoverability.The resultant PAM@Tre hydrogel is capable of full shape recovery after 10,000 loading/unloading cycles at a strain of 500%.Even after being stretched at a strain of 2500%,it can recover to its original shape within 10 seconds.Moreover,the molecular movement of trehalose also endows the PAM@Tre hydrogel with fracture energy and toughness as high as~9000 J m^(-2) and~1600 kJ m^(-3),respec-tively,leading to strong resistance to both static and dynamic piercing.The PAM@Tre hydrogel is thus believed to have enormous potentials in protection devices,bionic skin,soft actuator,and stretchable electronics.展开更多
In this work,the dependency of the polarization(P)-electric field(E)loop area A of lead free ferro-electrics Na_(0.5)Bi_(0.5)TiO_(3)(NBT), K_(0.5)Bi_(0.5)TiO_(3)(KBT),and Na_(0.25)K_(0.25)Bi_(0.5)TiO_(3)(NKBT)on the a...In this work,the dependency of the polarization(P)-electric field(E)loop area A of lead free ferro-electrics Na_(0.5)Bi_(0.5)TiO_(3)(NBT), K_(0.5)Bi_(0.5)TiO_(3)(KBT),and Na_(0.25)K_(0.25)Bi_(0.5)TiO_(3)(NKBT)on the amplitude(E0)of the electric field is studied.Based on the nature of the hysteresis loop with increasing E0,the lnA versus lnE0 graph is divided into three stages and the scaling exponents of each stage are estimated.In the third stage,NBT,KBT,and NKBT show different shapes of P-E loops(square,slanted and pinched,respectively).Although,almost similar slopes in the third stage are obtained from the lnA versus lnE0 graphs of KBT and NKBT,the formation of pinched P-E loop of NKBT is discussed based on the current-time curve under a complete cycle of the applied electric field.The shape of the P-E loop also affects the recoverable energy storage density(Wrec)of the material.Similar to the scaling of A,the variation of lnWrec with lnE0 of NBT,KBT and NKBT are examined.Interestingly,three stages are only noticed in the lnWrec-lnE0 curve of pinched P-E loop(NKBT),whereas lnWrec linearly increases with lnE0 for square and slanted P-E loop.Such type of behavior of Wrec of NKBT is explained based on the reversible domain switching mechanism of the pinched P-E loop.展开更多
The nutritional situation of the elderly is closely related to the occurrence and development of many diseases.How to reduce the damage of surgery,and improve the postoperative survival rate and quality of life in mal...The nutritional situation of the elderly is closely related to the occurrence and development of many diseases.How to reduce the damage of surgery,and improve the postoperative survival rate and quality of life in malnourished elderly patients is very important.Through the elderly malnutrition perioperative risk factors analysis,we make strategies for risk factors of perioperative-related prevention,from preoperative,intraoperative,and postoperative management of patients,to improve the patient’s life.展开更多
Sustainably managing vehicles at their end-of-life stage(ELVs)presents significant potential forresource recovery,effectively addressing resource scarcity through the closure of the material loop.While ELVs in countri...Sustainably managing vehicles at their end-of-life stage(ELVs)presents significant potential forresource recovery,effectively addressing resource scarcity through the closure of the material loop.While ELVs in countries like Morocco have traditionally been treated as waste rather than secondaryresource material(SRM),they have the potential to reduce reliance on primary materials when usedjudiciously.Despite policymakers aiming for increased resource efficiency in the automobile sector,there is limited research exploring the role of the informal sector in recovering materials and parts fromELVs.This study investigates the ELV processing scenario at Salmia scrap market,recognized as one of Africa’s largest informal markets for ELVs.Using a mass-balance approach,the disposal of sedan cars isexamined,and a conceptual framework illustrating the process flow and interactions among multiplestakeholders is developed.From sampled sedan cars,approximately 7% of aluminum and 76%of iron,by weight,are recovered.These findings contribute to estimating the potential for recycling andrecovering materials from ELVs processed by the informal sector in Morocco.In a standard operationalcontext,estimations suggest that the sector holds substantial potential to recover aluminum and iron by2030.This underscores the importance of formalizing operations and integrating informal players intothe value chain to effectively address resource scarcity within a circular economy.展开更多
基金supported by National Natural Science Foundation of China(No.62172436)Additionally,it is supported by Natural Science Foundation of Shaanxi Province(No.2023-JC-YB-584)Engineering University of PAP’s Funding for Scientific Research Innovation Team and Key Researcher(No.KYGG202011).
文摘Cloud storage,a core component of cloud computing,plays a vital role in the storage and management of data.Electronic Health Records(EHRs),which document users’health information,are typically stored on cloud servers.However,users’sensitive data would then become unregulated.In the event of data loss,cloud storage providers might conceal the fact that data has been compromised to protect their reputation and mitigate losses.Ensuring the integrity of data stored in the cloud remains a pressing issue that urgently needs to be addressed.In this paper,we propose a data auditing scheme for cloud-based EHRs that incorporates recoverability and batch auditing,alongside a thorough security and performance evaluation.Our scheme builds upon the indistinguishability-based privacy-preserving auditing approach proposed by Zhou et al.We identify that this scheme is insecure and vulnerable to forgery attacks on data storage proofs.To address these vulnerabilities,we enhanced the auditing process using masking techniques and designed new algorithms to strengthen security.We also provide formal proof of the security of the signature algorithm and the auditing scheme.Furthermore,our results show that our scheme effectively protects user privacy and is resilient against malicious attacks.Experimental results indicate that our scheme is not only secure and efficient but also supports batch auditing of cloud data.Specifically,when auditing 10,000 users,batch auditing reduces computational overhead by 101 s compared to normal auditing.
基金supported by the National Natural Science Foundation of China(Nos.12132002,12202044)。
文摘In the process of stage separation of recoverable liquid launch vehicles,because of the large amount of residual fuel in the storage tanks,the influence of liquid sloshing on separation safety must be considered.Considering calculation simplicity and operation practicability,the Moving Pulsating Ball Model(MPBM)of large amplitude liquid sloshing is introduced into the calculation of launch vehicle stage separation.Combining the dynamic equation of the model with the energy relationship during"breathing movement",the formula calculating the force of liquid on the rigid body is derived.Compared with the calculations of commercial CFD calculation software,the accuracy of MPBM model is verified.Then,all the external forces and moments are applied to the rigid body of the stages,so that the translational and rotational dynamic equations of the stages are obtained respectively.According to the relative position of the two stages,the geometric shape of the interstage section and the engine of the second stage,the minimum clearance in the separation process can be decided to guarantee that the separation process is safe.
基金National Basic Research Program of China (No. G1999043606)
文摘Calculation of the groundwater recoverable resource is the main part of groundwater resource evaluation. The three-dimensional groundwater flow model in Linfen Basin was established by GMS software. Then the numerical model was calibrated by observed groundwater level from February to December in 2 000. Based on the calibrated model, the groundwater recoverable resource is calculated. The simulation result shows that under the given value of the groundwater recoverable resource, the groundwater level would decrease significantly in the first 1 000 days, while the water level would drop slowly in 1 000 to 2 000 days, and the water level change tend to be stable after 2000 days.
文摘As a significant inducement during the development of oil and gas,the role of remaining recoverable reserves is more observable especially in the later phase of development of oilfield.Depended on the production decline method in petroleum reservoir engineering,a new model of predicting recoverable and remaining recoverable reserves has been
文摘This paper reviews the recoverable satellites China has developed over the past forty years.The main missions,technical specifications,scientific and technical experiments of these satellites,including the SJ-10 scientific experiment satellite launched on April 6,2016 are introduced.Recommendations for future technical upgrades for recoverable satellites are also proposed in the paper.
文摘Based on experimental study of the time dependence of the recoverable shape memory effect (SME)of shape memory alloys Ti50Ni50,Ti50Ni48Cu2 and Ti50Ni45Cu5 an empirical re- lationship between recoverable strain energy,U_r,and temperature,T.was derived as: U_r=U_o[1-exp(-mT_R^n)] where m—characteristic constant related to material,and n-shape-temperature sensitivity. The Johnson-Mehl-Aerami's phenomenological description of the time dependence of phase transformation was adopted to obtain a semiquantitative relationship associated with recoverable SME.between thermoelastic martensite transformation and temperature.This semiquantitative relationship is correspondent with the empirical expression.
基金supported by the National Natural Science Foundation of China(Nos.11672264,11972320)the Zhejiang Provincial Natural Science Foundation(No.LZ17A020001)。
文摘The ferroelectric superlattices have been widely studied due to their distinguished electromechanical coupling properties.Under different biaxial mismatch strains,ferroelectric superlattices exhibit different domain structures and electromechanical coupling properties.A three-dimensional phase field model is employed to investigate the detailed domain evolution and electromechanical properties of the PbTiO_(3)/SrTiO_(3)(PTO/STO)superlattices with different biaxial mismatch strains.The phase field simulations show that the ferroelectric superlattice exhibits large electrostrain in the stacking direction when an external field is applied.Under a large compressive mismatch strain,vortex domains appear in ferroelectric layers with the thickness of 4 nm.The vortex domains become stable cdomain under a large external electric field,which remains when the electric field is removed.When the initial compressive mismatch strain decreases gradually,the waved or a1/a2 domains replaces the initial vortex domains in the absence of electric field.The fully polarized c-domain by a large electric field switches to diagonal direction domain or a/c domain when the electric field is small.Furthermore,when a biaxial tensile strain is applied to the superlattice,ferroelectric domains switch back to the initial a1/a2 twin-like domain structure,resulting in the recoverable and large electrostrain.This provides an effective way to obtain the large and recoverable electrostrain for the engineering application.
基金Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA04020000)United Funding from National Natural Science Foundation of China and Chinese Academy of Sciences。
文摘SJ-10 is a recoverable scientific experiment satellite specially for the space experiments of microgravity physics science and space life science.This mission was officially started on 31 December 2012,and the satellite was launched on 6 April 2016.This paper introduces briefly the SJ-10 mission,the progress of SJ-10 engineering and the project constitution of sciences experiments onboard SJ-10.The purpose of this mission is to discover the law of matter movement and the rule of life activity that cannot be discovered on the ground due to the existence of gravity,and to know the acting mechanism on organisms by the complex radiation of space that cannot be simulated on the ground.
基金supported by the National Natural Science Foundation of China(No.20572131,20842007)Natural Science Basic Research Plan in Shaanxi Province of China(No.SJ08-ZT02) for financial support.
文摘A new free recoverable and reusable mono-alkaloid-type ligand has been synthesized by a simple method. With highly polar groups, the ligand can be recycled and reused eight times to prepare ethyl （2R,3S）-2,3-dihydroxy-3-phenylpropionate with high yield and ee via asymmetric dihydroxylation （AD） reaction. C 2009 Sheng Yong Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
文摘This paper presents a conceptual framework of integrated waste management which focuses on all stages of product life cycle. A mechanism of resource recovery motivating from waste in economic system （designers, producers, consumers, stakeholders in the field of disposal of the product） is suggested. The classification of institutional and economic instruments in the field of waste management as recoverable resources is developed. The author has proposed a scientific and methodical approach to the formation of an integrated waste management as recoverable resources, which is based on a set of methods of economic incentives at all stages of product life cycle and ensures the maximum possible and the environmentally safe management of wastes containing valuable resource components.
文摘Total recoverable concentration of five elements of concern: Aluminum, Iron, Manganese, Arsenic and Lead (Al, Fe, Mn, As, Pb) were measured by inductively coupled plasma atomic emission spectrometry, and mass spectrometry. The results show that sediment texture plays a controlling role in the concentrations and their spatial distribution. Principal Component Analysis and Cluster Analysis were used to analyze the grain sizes of the sediments. Result of texture analysis classified the samples into three main components in percentages: sand, silt, and clay. Significant differences among the element concentrations in the three groups were observed, and the concentrations of the elements in each group are reported in this study. Most of the elements have their highest concentrations in the fine-grained samples with clay playing an important role, in comparison with the sand component of the soil/sediment samples. There appears to be a strong correlation between samples with high silt, and clay content with the areas of elevated concentrations for Al, Fe, and Mn. There was a strong correlation between aluminum and lead with clay;lead with silt;and sand with manganese, aluminum, and lead. However, there was no strong relationship between the soil textures and iron or arsenic. All elements measured were statistically significant (at P ≤ 0.05) by watershed. The upland areas, and depositional areas’ spatial variation of element concentrations in the sediments were also observed, which was in line with the spatial distribution of the grain size and was thought to be related to the watersheds hydrological dynamics.
文摘In order to fulfil the microgravity requirements for space experiments, improved technology for the microgravity environment is proposed, including that for raising the orbital altitude, optimizing the layout of the disturbance source, using IN-thrusters instead of 5 N-thrusters, etc. In addition, evaluation of the microgravity environment of the recoverable satellite was also conducted using on-orbit micro-vibration measurement, on-orbit experiment and data analysis technologies. The microgravity level of the SJ-l0 recoverable satellite in China is compared with the spacecraft used for carrying out space science experiments internationally. This paper describes the microgravity environment of the SJ- 10 recoverable satellite, and its importance for analysing space experimental results.
文摘The paper introduces a kind of full length recoverable resin metal bolts, expounds its structural principle and stress features, and gives some instances in laboratory tests and underground tests. The results show that full length recoverable resin metal bolts can be used for supporting the walls of class Ⅰ～Ⅲ mining gateways, that the anchoring force is 50 kN or so, and that the recoverability rate is more than 80%, thus the supporting effect is better than that of split set bolts.
文摘On August 25,1992,China suc-cessfully returned its 13th recover-able satellite from orbit after 16days’operation.The satellite is thefirst one of the second generation ofthe Chinese recoverable satellites.Itemployed initially the newly devel-oped LEO control technology.Compared with former recoverablesatellites,its capability was im-proved a lot by using many newtechnologies on satellite structure,on-board detection equipment andsatellite control,etc..
基金This work was supported by the National Natural Science Foundation of China[51873064,51603068,11772283]Natural Science Foundation of Shanghai[20ZR1418200,17ZR1440600].
文摘It remains a challenge to achieve rapidly recoverable hydrogels by molecular hydrogen-bonding interaction because of its slow inter-action kinetics.This work for the first time reports a trehalose(Tre)-based molecular movement mechanism inside a single network of polyacrylamide(PAM)that accelerates the kinetics of hydrogenbonding interaction,and thereby endows the hydrogel with high toughness and rapid shape and mechanical recoverability.The resultant PAM@Tre hydrogel is capable of full shape recovery after 10,000 loading/unloading cycles at a strain of 500%.Even after being stretched at a strain of 2500%,it can recover to its original shape within 10 seconds.Moreover,the molecular movement of trehalose also endows the PAM@Tre hydrogel with fracture energy and toughness as high as~9000 J m^(-2) and~1600 kJ m^(-3),respec-tively,leading to strong resistance to both static and dynamic piercing.The PAM@Tre hydrogel is thus believed to have enormous potentials in protection devices,bionic skin,soft actuator,and stretchable electronics.
基金Author SA gratefully acknowledges the financial support pro-vided by the CSIR-EMRII(Ref.No.0194/NS)SERB,Department of Science and Technology(CRG/2020/001509)India to carry out this work.Author KB acknowledges DST-INSPIRE,India(Fellowship Code No.IF160462)for financial assistance.
文摘In this work,the dependency of the polarization(P)-electric field(E)loop area A of lead free ferro-electrics Na_(0.5)Bi_(0.5)TiO_(3)(NBT), K_(0.5)Bi_(0.5)TiO_(3)(KBT),and Na_(0.25)K_(0.25)Bi_(0.5)TiO_(3)(NKBT)on the amplitude(E0)of the electric field is studied.Based on the nature of the hysteresis loop with increasing E0,the lnA versus lnE0 graph is divided into three stages and the scaling exponents of each stage are estimated.In the third stage,NBT,KBT,and NKBT show different shapes of P-E loops(square,slanted and pinched,respectively).Although,almost similar slopes in the third stage are obtained from the lnA versus lnE0 graphs of KBT and NKBT,the formation of pinched P-E loop of NKBT is discussed based on the current-time curve under a complete cycle of the applied electric field.The shape of the P-E loop also affects the recoverable energy storage density(Wrec)of the material.Similar to the scaling of A,the variation of lnWrec with lnE0 of NBT,KBT and NKBT are examined.Interestingly,three stages are only noticed in the lnWrec-lnE0 curve of pinched P-E loop(NKBT),whereas lnWrec linearly increases with lnE0 for square and slanted P-E loop.Such type of behavior of Wrec of NKBT is explained based on the reversible domain switching mechanism of the pinched P-E loop.
基金supported by Emerging Industry Leading Talent Project of Shanxi Province(No.2020587).
文摘The nutritional situation of the elderly is closely related to the occurrence and development of many diseases.How to reduce the damage of surgery,and improve the postoperative survival rate and quality of life in malnourished elderly patients is very important.Through the elderly malnutrition perioperative risk factors analysis,we make strategies for risk factors of perioperative-related prevention,from preoperative,intraoperative,and postoperative management of patients,to improve the patient’s life.
文摘Sustainably managing vehicles at their end-of-life stage(ELVs)presents significant potential forresource recovery,effectively addressing resource scarcity through the closure of the material loop.While ELVs in countries like Morocco have traditionally been treated as waste rather than secondaryresource material(SRM),they have the potential to reduce reliance on primary materials when usedjudiciously.Despite policymakers aiming for increased resource efficiency in the automobile sector,there is limited research exploring the role of the informal sector in recovering materials and parts fromELVs.This study investigates the ELV processing scenario at Salmia scrap market,recognized as one of Africa’s largest informal markets for ELVs.Using a mass-balance approach,the disposal of sedan cars isexamined,and a conceptual framework illustrating the process flow and interactions among multiplestakeholders is developed.From sampled sedan cars,approximately 7% of aluminum and 76%of iron,by weight,are recovered.These findings contribute to estimating the potential for recycling andrecovering materials from ELVs processed by the informal sector in Morocco.In a standard operationalcontext,estimations suggest that the sector holds substantial potential to recover aluminum and iron by2030.This underscores the importance of formalizing operations and integrating informal players intothe value chain to effectively address resource scarcity within a circular economy.
