With expressway development and environment protection consciousness improving, slope protection technology with vegetation has drawn much more attention. From the perspective of ecology, Baoji-Hanzhong Expressway max...With expressway development and environment protection consciousness improving, slope protection technology with vegetation has drawn much more attention. From the perspective of ecology, Baoji-Hanzhong Expressway maximized slope protection technology with vegetation and formed attracting landscapes on basis of eco-protection. This research introduced the technology of Baoji-Hanzhong Expressway, and explored a low-cost and effective biological slopeprotection way, suitable for Baoji-Hanzhong Expressway, according to slope protection technologies, at home and abroad, with botany, water and soil conservation engineering, and architecture, which fixed and stabilized slopes, prevented rainfall scouring, and advanced slope protection development in China.展开更多
The use of non-power frequency components for protection measurements in an area that has received relatively little attention. Although work on the use of switched stack tuners has been reported for fault detection, ...The use of non-power frequency components for protection measurements in an area that has received relatively little attention. Although work on the use of switched stack tuners has been reported for fault detection, the sensitivity of switched arrangements is limited by scnsitivity of directional detectors for switching purposes. This paper presents an alternative non-switching scheme which is relatively simple.A simplified typical 400kV system with the line trap, stack tuner, coupling capacitor and bus capacitance to earth is considered. Fault studies by using the EMTP have been carried out, frequency-dependent pararnctcrs are used for the line representation. Arcing faults have also bccn investigated and the results show a great promise of the scheme.展开更多
The incidence of intractable age-related neurodegenerative conditions such as Alzheimer's and Parkinson's diseases and age-related macular degeneration is projected to increase substantially over the coming decades ...The incidence of intractable age-related neurodegenerative conditions such as Alzheimer's and Parkinson's diseases and age-related macular degeneration is projected to increase substantially over the coming decades with the ageing of the global population. While the burden of disease associ- ated with other chronic conditions has decreased in recent times due to improved diagnosis and treatment, current therapies for neurodegenerative diseases still fall short in that they are only effective in treating signs and symptoms - they do little to slow or prevent disease progress. Thus, there is an urgent need for treatments that address disease progression.展开更多
A cation exchange membrane is permeable to cation and impermeable to anions. When the membrane is directly coated on a metal surface, the coating will not provide corrosion protection to the substrate, and it delamina...A cation exchange membrane is permeable to cation and impermeable to anions. When the membrane is directly coated on a metal surface, the coating will not provide corrosion protection to the substrate, and it delaminated in salt fog testing. When the barrier to anion membrane coated on the surface of a primer, it inhibits anions to diffuse from the environment through the coating.展开更多
In the paper, it is discussed reinforced coastal zones with resort-recreational functions, destructed in terms of anthropogenic pressure of the Black Sea, Georgia. Results of many years’ observations and researches p...In the paper, it is discussed reinforced coastal zones with resort-recreational functions, destructed in terms of anthropogenic pressure of the Black Sea, Georgia. Results of many years’ observations and researches prove low effectiveness of active methods of coastal protection, mostly causing and provoking intensive degradation of the beaches. Article highlights developing and constructing of free and unbounded beaches as an optimal coastal protection approach. Successful example of this approach was developing of coastal zone in 90s, in Gagra (West Georgia), Black Sea. Positive impact of this kind of artificial beach still survives. In the thesis, it is presented an attempt to scientifically prove extrapolation-traduction on the other similar coasts of the recovery of Gagra Zone beach. Based on morphodynamic analysis and comparison, according to the priorities of major features of reinforced coasts, it turned out that coast of three similar objects (Gagra, Ochamchire and Sokhumi) show homogenous aspects. Scientific expediency of providing extrapolation on other similar objects of etalon objects i.e. Gagra Beach recovered by successful coastal protection experiment. Thereby, for the purposes of creating free-artificial beach, choosing of wrecking zone of Ochamchire is based on coastal protection effectiveness and economical principals, including technical-economical effectiveness.展开更多
Magnesium(Mg)alloys are lightweight materials with excellent mechanical properties,making them attractive for various applications,including aerospace,automotive,and biomedical industries.However,the practical applica...Magnesium(Mg)alloys are lightweight materials with excellent mechanical properties,making them attractive for various applications,including aerospace,automotive,and biomedical industries.However,the practical application of Mg alloys is limited due to their high susceptibility to corrosion.Plasma electrolytic oxidation(PEO),or micro-arc oxidation(MAO),is a coating method that boosts Mg alloys'corrosion resistance.However,despite the benefits of PEO coatings,they can still exhibit certain limitations,such as failing to maintain long-term protection as a result of their inherent porosity.To address these challenges,researchers have suggested the use of inhibitors in combination with PEO coatings on Mg alloys.Inhibitors are chemical compounds that can be incorporated into the coating or applied as a post-treatment to further boost the corrosion resistance of the PEO-coated Mg alloys.Corrosion inhibitors,whether organic or inorganic,can act by forming a protective barrier,hindering the corrosion process,or modifying the surface properties to reduce susceptibility to corrosion.Containers can be made of various materials,including polyelectrolyte shells,layered double hydroxides,polymer shells,and mesoporous inorganic materials.Encapsulating corrosion inhibitors in containers fully compatible with the coating matrix and substrate is a promising approach for their incorporation.Laboratory studies of the combination of inhibitors with PEO coatings on Mg alloys have shown promising results,demonstrating significant corrosion mitigation,extending the service life of Mg alloy components in aggressive environments,and providing self-healing properties.In general,this review presents available information on the incorporation of inhibitors with PEO coatings,which can lead to improved performance of Mg alloy components in demanding environments.展开更多
Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this...Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this continuous changes in generation condition, the fault current level in network will be affected, this changes in fault current level will affect in the coordination between protection relays and to keep the coordination at right way, an adaptive protection system is required that can adaptive its setting according to generation changes, the fault current level in each case is evaluated using ETAP software, and the required relay setting in each case is also evaluated using Grey Wolf Optimizer (GWO) algorithm, and to select suitable setting which required in each condition, to select the active setting group of protection relay according to generation capacity, central protection unite can be used, and to improve protection stability and minimizing relays tripping time, a proposed method for selecting suitable backup relay is used, which leads to decrease relays tripping time and increase system stability, output settings for relays in all cases achieved our constrains.展开更多
Battery safety has attracted considerable attention worldwide due to the rapid development of wearable electronics and the steady increase in the production and use of electric vehicles.As battery failures are often a...Battery safety has attracted considerable attention worldwide due to the rapid development of wearable electronics and the steady increase in the production and use of electric vehicles.As battery failures are often associated with mechanical-thermal coupled behaviors,protective shielding materials with excellent mechanical robustness and flame-retardant properties are highly desired to mitigate thermal runaway.However,most of the thermal insulating materials are not strong enough to protect batteries from mechanical abuse,which is one of the most critical scenarios with catastrophic consequences.Here,inspired by wood,we have developed an effective approach to engineer a hierarchical nanocomposite via self-assembly of calcium silicate hydrate and polyvinyl alcohol polymer chains(referred as CSH wood).The versatile protective material CSH wood demonstrates an unprecedented combination of light weight(0.018 g cm-3),high stiffness(204 MPa in the axial direction),negative Poisson's ratio(-0.15),remarkable toughness(6.67×105 J m-3),superior thermal insulation(0.0204 W m-1 K-1 in the radial direction),and excellent fire retardancy(UL94-V0).When applied as a protective cover or a protective layer within battery packages,the tough CSH wood can resist high-impact load and block heat diffusion to block or delay the spread of fire,therefore significantly reducing the risk of property damage or bodily injuries caused by battery explosions.This work provides new pathways for fabricating advanced thermal insulating materials with large scalability and demonstrates great potential for the protection of electronic devices.展开更多
Spinal cord injury is a serious disease of the central nervous system involving irreversible nerve injury and various organ system injuries.At present,no effective clinical treatment exists.As one of the artificial hi...Spinal cord injury is a serious disease of the central nervous system involving irreversible nerve injury and various organ system injuries.At present,no effective clinical treatment exists.As one of the artificial hibernation techniques,mild hypothermia has preliminarily confirmed its clinical effect on spinal cord injury.However,its technical defects and barriers,along with serious clinical side effects,restrict its clinical application for spinal cord injury.Artificial hibernation is a futureoriented disruptive technology for human life support.It involves endogenous hibernation inducers and hibernation-related central neuromodulation that activate particular neurons,reduce the central constant temperature setting point,disrupt the normal constant body temperature,make the body adapt"to the external cold environment,and reduce the physiological resistance to cold stimulation.Thus,studying the artificial hibernation mechanism may help develop new treatment strategies more suitable for clinical use than the cooling method of mild hypothermia technology.This review introduces artificial hibernation technologies,including mild hypothermia technology,hibernation inducers,and hibernation-related central neuromodulation technology.It summarizes the relevant research on hypothermia and hibernation for organ and nerve protection.These studies show that artificial hibernation technologies have therapeutic significance on nerve injury after spinal co rd injury through inflammatory inhibition,immunosuppression,oxidative defense,and possible central protection.It also promotes the repair and protection of res pirato ry and digestive,cardiovascular,locomoto r,urinary,and endocrine systems.This review provides new insights for the clinical treatment of nerve and multiple organ protection after spinal cord injury thanks to artificial hibernation.At present,artificial hibernation technology is not mature,and research fa ces various challenges.Neve rtheless,the effort is wo rthwhile for the future development of medicine.展开更多
In this paper,an efficient unequal error protection(UEP)scheme for online fountain codes is proposed.In the buildup phase,the traversing-selection strategy is proposed to select the most important symbols(MIS).Then,in...In this paper,an efficient unequal error protection(UEP)scheme for online fountain codes is proposed.In the buildup phase,the traversing-selection strategy is proposed to select the most important symbols(MIS).Then,in the completion phase,the weighted-selection strategy is applied to provide low overhead.The performance of the proposed scheme is analyzed and compared with the existing UEP online fountain scheme.Simulation results show that in terms of MIS and the least important symbols(LIS),when the bit error ratio is 10-4,the proposed scheme can achieve 85%and 31.58%overhead reduction,respectively.展开更多
Objective:To reveal the molecular mechanism underlying the compatibility of Salvia miltiorrhiza Bge(S.miltiorrhiza,Dan Shen)and C.tinctorius L.(C.tinctorius,Hong Hua)as an herb pair through network pharmacology and su...Objective:To reveal the molecular mechanism underlying the compatibility of Salvia miltiorrhiza Bge(S.miltiorrhiza,Dan Shen)and C.tinctorius L.(C.tinctorius,Hong Hua)as an herb pair through network pharmacology and subsequent experimental validation.Methods:Network pharmacology was applied to construct an active ingredient-efficacy target-disease protein network to reveal the unique regulation pattern of s.miltiorrhiza and C.tinctorius as herb pair.Molecular docking was used to verify the binding of the components of these herbs and their potential targets.An H9c2 glucose hypoxia model was used to evaluate the efficacy of the components and their synergistic effects,which were evaluated using the combination index.Western blot was performed to detect the protein expression of these targets.Results:Network pharmacology analysis revealed 5 pathways and 8 core targets of s.miltiorrhiza and C.tinctorius in myocardial protection.Five of the core targets were enriched in the hypoxia-inducible factor-1(HIF-1)signaling pathway.S.miltiorrhiza-C.tinctorius achieved vascular tone mainly by regulating the target genes of the HIF-1 pathway.As an upstream gene of the HIF-1 pathway,STAT3 can be activated by the active ingredients cryptotanshinone(Ctan),salvianolic acid B(Sal.B),and myricetin(Myric).Cell experiments revealed that Myric,Sal.B,and Ctan also exhibited synergistic myocardial protective activity.Molecular docking verified the strong binding of Myric,Sal.B,and Ctan to STAT3.Western blot further showed that the active ingredients synergistically upregulated the protein expressionof STAT3.Conclusion:The pharmacodynamic transmission analysis revealed that the active ingredients of S.miltiorrhiza and C.tinctorius can synergistically resist ischemia through various targets and pathways.This study provides a methodological reference for interpreting traditional Chinese medicine compatibility.展开更多
The car-hailing platform based on Internet of Vehicles(IoV)tech-nology greatly facilitates passengers’daily car-hailing,enabling drivers to obtain orders more efficiently and obtain more significant benefits.However,...The car-hailing platform based on Internet of Vehicles(IoV)tech-nology greatly facilitates passengers’daily car-hailing,enabling drivers to obtain orders more efficiently and obtain more significant benefits.However,to match the driver closest to the passenger,it is often necessary to process the location information of the passenger and driver,which poses a considerable threat to privacy disclosure to the passenger and driver.Targeting these issues,in this paper,by combining blockchain and Paillier homomorphic encryption algorithm,we design a secure blockchain-enabled IoV scheme with privacy protection for online car-hailing.In this scheme,firstly,we propose an encryp-tion scheme based on the lattice.Thus,the location information of passengers and drivers is encrypted in this system.Secondly,by introducing Paillier homomorphic encryption algorithm,the location matching of passengers and drivers is carried out in the ciphertext state to protect their location privacy.At last,blockchain technology is used to record the transactions in online car-hailing,which can provide a security guarantee for passengers and drivers.And we further analyze the security and performance of this scheme.Compared with other schemes,the experimental results show that the proposed scheme can protect the user’s location privacy and have a better performance.展开更多
Most studies have conducted experiments on predicting energy consumption by integrating data formodel training.However, the process of centralizing data can cause problems of data leakage.Meanwhile,many laws and regul...Most studies have conducted experiments on predicting energy consumption by integrating data formodel training.However, the process of centralizing data can cause problems of data leakage.Meanwhile,many laws and regulationson data security and privacy have been enacted, making it difficult to centralize data, which can lead to a datasilo problem. Thus, to train the model while maintaining user privacy, we adopt a federated learning framework.However, in all classical federated learning frameworks secure aggregation, the Federated Averaging (FedAvg)method is used to directly weight the model parameters on average, which may have an adverse effect on te model.Therefore, we propose the Federated Reinforcement Learning (FedRL) model, which consists of multiple userscollaboratively training the model. Each household trains a local model on local data. These local data neverleave the local area, and only the encrypted parameters are uploaded to the central server to participate in thesecure aggregation of the global model. We improve FedAvg by incorporating a Q-learning algorithm to assignweights to each locally uploaded local model. And the model has improved predictive performance. We validatethe performance of the FedRL model by testing it on a real-world dataset and compare the experimental results withother models. The performance of our proposed method in most of the evaluation metrics is improved comparedto both the centralized and distributed models.展开更多
In edge computing,a reasonable edge resource bidding mechanism can enable edge providers and users to obtain benefits in a relatively fair fashion.To maximize such benefits,this paper proposes a dynamic multiattribute...In edge computing,a reasonable edge resource bidding mechanism can enable edge providers and users to obtain benefits in a relatively fair fashion.To maximize such benefits,this paper proposes a dynamic multiattribute resource bidding mechanism(DMRBM).Most of the previous work mainly relies on a third-party agent to exchange information to gain optimal benefits.It isworth noting thatwhen edge providers and users trade with thirdparty agents which are not entirely reliable and trustworthy,their sensitive information is prone to be leaked.Moreover,the privacy protection of edge providers and users must be considered in the dynamic pricing/transaction process,which is also very challenging.Therefore,this paper first adopts a privacy protection algorithm to prevent sensitive information from leakage.On the premise that the sensitive data of both edge providers and users are protected,the prices of providers fluctuate within a certain range.Then,users can choose appropriate edge providers by the price-performance ratio(PPR)standard and the reward of lower price(LPR)standard according to their demands.The two standards can be evolved by two evaluation functions.Furthermore,this paper employs an approximate computing method to get an approximate solution of DMRBM in polynomial time.Specifically,this paper models the bidding process as a non-cooperative game and obtains the approximate optimal solution based on two standards according to the game theory.Through the extensive experiments,this paper demonstrates that the DMRBM satisfies the individual rationality,budget balance,and privacy protection and it can also increase the task offloading rate and the system benefits.展开更多
A novel operation control method for relay protection in flexible DC distribution networks with distributed power supply is proposed to address the issue of inaccurate fault location during relay protection,leading to...A novel operation control method for relay protection in flexible DC distribution networks with distributed power supply is proposed to address the issue of inaccurate fault location during relay protection,leading to poor performance.The method combines a fault-tolerant fault location method based on long-term and short-term memory networks to accurately locate the fault section.Then,an operation control method for relay protection based on adaptive weight and whale optimization algorithm(WOA)is used to construct an objective function considering the shortest relay protection action time and the smallest impulse current.The adaptive weight and WOA are employed to obtain the optimal strategy for relay protection operation control,reducing the action time and impulse current.Experimental results demonstrate the effectiveness of the proposed method in accurately locating faults and improving relay protection performance.The longest operation time is reduced by 4.7023 s,and the maximum impulse current is limited to 0.3 A,effectively controlling the impact of large impulse currents and enhancing control efficiency.展开更多
The DC grid technology of multi-power supply and multi-drop-point power reception is an effective solution for large-scale renewable energy integration into the power grid.Line-commutated converter-Voltage source conv...The DC grid technology of multi-power supply and multi-drop-point power reception is an effective solution for large-scale renewable energy integration into the power grid.Line-commutated converter-Voltage source converter(LCC-VSC)power grids are one of the more important developmental directions of the future power grid that have occured in recent years.But the multi-terminal high voltage direct current system has the problems of inconsistent boundary characteristics,inconsistent control,and fault response characteristics,which puts higher requirements on the protection scheme.Thus,a completely new protection principle is proposed in this paper.Firstly,the fault characteristics of distributed capacitance current are analyzed.The reactive power calculated by the distribution parameters of different frequencies is different.Subsequently,the fault characteristics of DC reactive power are analyzed,and a DC reactive power extraction algorithm is proposed.The polarity of the multi-band DC reactive power is used to construct the protection scheme.Finally,the LCC-VSC power grid model verifies the correctness and superiority of the proposed protection scheme.The proposed scheme uses DC reactive power instead of fault current to solve the long delay problem caused by distributed capacitance.Compared with the prior art,the proposed solution is not affected by distributed capacitance and has a stronger anti-interference ability(600Ω+10 dB+1 ms).展开更多
Line-commutated converter-voltage source converter(LCC-VSC)power transmission technology does not have the problem of communication failure very usually.It therefore can support the long-distance,long-capacity transmi...Line-commutated converter-voltage source converter(LCC-VSC)power transmission technology does not have the problem of communication failure very usually.It therefore can support the long-distance,long-capacity transmission of electric energy.However,factors such as topology,control strategy,and short-circuit capacities make the traditional protection principles not fully applicable to LCC-VSC hybrid transmission systems.To enhance the reliability of hybrid DC systems,a single-ended principle based on transmission coefficients is proposed and produced.First,the equivalent circuit of the LCC-VSC hybrid DC system is analyzed and the expression of the first traveling wave is deduced accordingly.Then,the concept of multi-frequency transmission coefficients is proposed by analyzing the amplitude-frequency,and the characteristics of each element.Finally,the LCC-VSCDC system model is built to verify the reliability and superiority of the principle itself.Theoretical analysis and experimental verification show that the principle has strong interference resistance.展开更多
In the current digital era, it is difficult to preserve the confidentiality, integrity, and availability of an organization’s information and technology assets against cyber attacks. Organizations cannot rely solely ...In the current digital era, it is difficult to preserve the confidentiality, integrity, and availability of an organization’s information and technology assets against cyber attacks. Organizations cannot rely solely on technical solutions for defense, since many cyber attacks attempt to exploit non-technical vulnerabilities such as how well employees comply with the organization’s cybersecurity policies. This study surveyed 245 randomly selected employees of government organizations in the Kingdom of Saudi Arabia with an electronically distributed questionnaire about factors that influence employees’ compliance with cybersecurity policies. The study found that ethical factors had the most influence on employee compliance with cybersecurity policies, followed in decreasing order of influence by legislative factors, technical factors, and administrative factors.展开更多
Under the epidemic situation of novel COVID-19 pneumonia, pregnant women belong to the susceptible population, and their physiological and psychological conditions are particularly worthy of attention. Diabetes patien...Under the epidemic situation of novel COVID-19 pneumonia, pregnant women belong to the susceptible population, and their physiological and psychological conditions are particularly worthy of attention. Diabetes patients during pregnancy may have a variety of complications, which can have a serious adverse impact on their own and fetal health. This article elaborates on home protection and diet and exercise guidance for pregnant women with diabetes in order to provide guidance for pregnant women with diabetes in a special period, and further prevent and control the pneumonia epidemic caused by novel COVID-19 infection in pregnant women.展开更多
Safety issue is still a problem nowadays for the large-scale application of lithium-ion batteries(LIBs)in electric vehicles and energy storage stations.The unsafe behaviors of LIBs arise from the thermal run-away,whic...Safety issue is still a problem nowadays for the large-scale application of lithium-ion batteries(LIBs)in electric vehicles and energy storage stations.The unsafe behaviors of LIBs arise from the thermal run-away,which is intrinsically triggered by the overcharging and overheating.To improve the safety of LIBs,various protection strategies based on self-actuating reaction control mechanisms(SRCMs)have been proposed,including redox shuttle,polymerizable monomer additive,potential-sensitive separator,thermal shutdown separator,positive-temperature-coefficient electrode,thermally polymerizable addi-tive,and reversible thermal phase transition electrolyte.As build-in protection mechanisms,these meth-ods can sensitively detect either the temperature change inside battery or the potential change of the electrode,and spontaneously shut down the electrode reaction at risky conditions,thus preventing the battery from going into thermal runaway.Given their advantages in enhancing the intrinsic safety of LIBs,this paper overviews the research progresses of SRCMs after a brief introduction of thermal runaway mechanism and limitations of conventional thermal runaway mitigating measures.More importantly,the current states and issues,key challenges,and future developing trends of SRCTs are also discussed and outlined from the viewpoint of practical application,aiming at providing insights and guidance for developing more effective SRCMs for LIBs.展开更多
文摘With expressway development and environment protection consciousness improving, slope protection technology with vegetation has drawn much more attention. From the perspective of ecology, Baoji-Hanzhong Expressway maximized slope protection technology with vegetation and formed attracting landscapes on basis of eco-protection. This research introduced the technology of Baoji-Hanzhong Expressway, and explored a low-cost and effective biological slopeprotection way, suitable for Baoji-Hanzhong Expressway, according to slope protection technologies, at home and abroad, with botany, water and soil conservation engineering, and architecture, which fixed and stabilized slopes, prevented rainfall scouring, and advanced slope protection development in China.
文摘The use of non-power frequency components for protection measurements in an area that has received relatively little attention. Although work on the use of switched stack tuners has been reported for fault detection, the sensitivity of switched arrangements is limited by scnsitivity of directional detectors for switching purposes. This paper presents an alternative non-switching scheme which is relatively simple.A simplified typical 400kV system with the line trap, stack tuner, coupling capacitor and bus capacitance to earth is considered. Fault studies by using the EMTP have been carried out, frequency-dependent pararnctcrs are used for the line representation. Arcing faults have also bccn investigated and the results show a great promise of the scheme.
基金supported by Sydney Medical School,Brain Foundation,Tenix Corporation and Sir Zelman Cowen Universities Fundsupported by a National Health and Medical Research Council of Australia(NHMRC)Early Career Fellowship
文摘The incidence of intractable age-related neurodegenerative conditions such as Alzheimer's and Parkinson's diseases and age-related macular degeneration is projected to increase substantially over the coming decades with the ageing of the global population. While the burden of disease associ- ated with other chronic conditions has decreased in recent times due to improved diagnosis and treatment, current therapies for neurodegenerative diseases still fall short in that they are only effective in treating signs and symptoms - they do little to slow or prevent disease progress. Thus, there is an urgent need for treatments that address disease progression.
文摘A cation exchange membrane is permeable to cation and impermeable to anions. When the membrane is directly coated on a metal surface, the coating will not provide corrosion protection to the substrate, and it delaminated in salt fog testing. When the barrier to anion membrane coated on the surface of a primer, it inhibits anions to diffuse from the environment through the coating.
文摘In the paper, it is discussed reinforced coastal zones with resort-recreational functions, destructed in terms of anthropogenic pressure of the Black Sea, Georgia. Results of many years’ observations and researches prove low effectiveness of active methods of coastal protection, mostly causing and provoking intensive degradation of the beaches. Article highlights developing and constructing of free and unbounded beaches as an optimal coastal protection approach. Successful example of this approach was developing of coastal zone in 90s, in Gagra (West Georgia), Black Sea. Positive impact of this kind of artificial beach still survives. In the thesis, it is presented an attempt to scientifically prove extrapolation-traduction on the other similar coasts of the recovery of Gagra Zone beach. Based on morphodynamic analysis and comparison, according to the priorities of major features of reinforced coasts, it turned out that coast of three similar objects (Gagra, Ochamchire and Sokhumi) show homogenous aspects. Scientific expediency of providing extrapolation on other similar objects of etalon objects i.e. Gagra Beach recovered by successful coastal protection experiment. Thereby, for the purposes of creating free-artificial beach, choosing of wrecking zone of Ochamchire is based on coastal protection effectiveness and economical principals, including technical-economical effectiveness.
文摘Magnesium(Mg)alloys are lightweight materials with excellent mechanical properties,making them attractive for various applications,including aerospace,automotive,and biomedical industries.However,the practical application of Mg alloys is limited due to their high susceptibility to corrosion.Plasma electrolytic oxidation(PEO),or micro-arc oxidation(MAO),is a coating method that boosts Mg alloys'corrosion resistance.However,despite the benefits of PEO coatings,they can still exhibit certain limitations,such as failing to maintain long-term protection as a result of their inherent porosity.To address these challenges,researchers have suggested the use of inhibitors in combination with PEO coatings on Mg alloys.Inhibitors are chemical compounds that can be incorporated into the coating or applied as a post-treatment to further boost the corrosion resistance of the PEO-coated Mg alloys.Corrosion inhibitors,whether organic or inorganic,can act by forming a protective barrier,hindering the corrosion process,or modifying the surface properties to reduce susceptibility to corrosion.Containers can be made of various materials,including polyelectrolyte shells,layered double hydroxides,polymer shells,and mesoporous inorganic materials.Encapsulating corrosion inhibitors in containers fully compatible with the coating matrix and substrate is a promising approach for their incorporation.Laboratory studies of the combination of inhibitors with PEO coatings on Mg alloys have shown promising results,demonstrating significant corrosion mitigation,extending the service life of Mg alloy components in aggressive environments,and providing self-healing properties.In general,this review presents available information on the incorporation of inhibitors with PEO coatings,which can lead to improved performance of Mg alloy components in demanding environments.
文摘Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this continuous changes in generation condition, the fault current level in network will be affected, this changes in fault current level will affect in the coordination between protection relays and to keep the coordination at right way, an adaptive protection system is required that can adaptive its setting according to generation changes, the fault current level in each case is evaluated using ETAP software, and the required relay setting in each case is also evaluated using Grey Wolf Optimizer (GWO) algorithm, and to select suitable setting which required in each condition, to select the active setting group of protection relay according to generation capacity, central protection unite can be used, and to improve protection stability and minimizing relays tripping time, a proposed method for selecting suitable backup relay is used, which leads to decrease relays tripping time and increase system stability, output settings for relays in all cases achieved our constrains.
基金the financial support from the National Key Research and Development Program of China(No.2021YFF0500802)the National Natural Science Foundation of China(No.51890904,No.52022022,and No.52278247)the Scientific Research and Innovation Plan of Jiangsu Province(KYCX21_0090)。
文摘Battery safety has attracted considerable attention worldwide due to the rapid development of wearable electronics and the steady increase in the production and use of electric vehicles.As battery failures are often associated with mechanical-thermal coupled behaviors,protective shielding materials with excellent mechanical robustness and flame-retardant properties are highly desired to mitigate thermal runaway.However,most of the thermal insulating materials are not strong enough to protect batteries from mechanical abuse,which is one of the most critical scenarios with catastrophic consequences.Here,inspired by wood,we have developed an effective approach to engineer a hierarchical nanocomposite via self-assembly of calcium silicate hydrate and polyvinyl alcohol polymer chains(referred as CSH wood).The versatile protective material CSH wood demonstrates an unprecedented combination of light weight(0.018 g cm-3),high stiffness(204 MPa in the axial direction),negative Poisson's ratio(-0.15),remarkable toughness(6.67×105 J m-3),superior thermal insulation(0.0204 W m-1 K-1 in the radial direction),and excellent fire retardancy(UL94-V0).When applied as a protective cover or a protective layer within battery packages,the tough CSH wood can resist high-impact load and block heat diffusion to block or delay the spread of fire,therefore significantly reducing the risk of property damage or bodily injuries caused by battery explosions.This work provides new pathways for fabricating advanced thermal insulating materials with large scalability and demonstrates great potential for the protection of electronic devices.
基金supported by the Key Projects of the National Natural Science Foundation of China,No.11932013(to XC)Key Military Logistics Research Projects,No.B WJ21J002(to XC)+4 种基金the Key projects of the Special Zone for National Defence Innovation,No.21-163-12-ZT006002-13(to XC)the National Nature Science Foundation of China No.82272255(to XC)the National Defense Science and Technology Outstanding Youth Science Fund Program,No.2021-JCIQ-ZQ-035(to XC)the Scientific Research Innovation Team Project of Armed Police Characteristic Medical Center,No.KYCXTD0104(to ZL)the National Natural Science Foundation of China Youth Fund,No.82004467(to BC)。
文摘Spinal cord injury is a serious disease of the central nervous system involving irreversible nerve injury and various organ system injuries.At present,no effective clinical treatment exists.As one of the artificial hibernation techniques,mild hypothermia has preliminarily confirmed its clinical effect on spinal cord injury.However,its technical defects and barriers,along with serious clinical side effects,restrict its clinical application for spinal cord injury.Artificial hibernation is a futureoriented disruptive technology for human life support.It involves endogenous hibernation inducers and hibernation-related central neuromodulation that activate particular neurons,reduce the central constant temperature setting point,disrupt the normal constant body temperature,make the body adapt"to the external cold environment,and reduce the physiological resistance to cold stimulation.Thus,studying the artificial hibernation mechanism may help develop new treatment strategies more suitable for clinical use than the cooling method of mild hypothermia technology.This review introduces artificial hibernation technologies,including mild hypothermia technology,hibernation inducers,and hibernation-related central neuromodulation technology.It summarizes the relevant research on hypothermia and hibernation for organ and nerve protection.These studies show that artificial hibernation technologies have therapeutic significance on nerve injury after spinal co rd injury through inflammatory inhibition,immunosuppression,oxidative defense,and possible central protection.It also promotes the repair and protection of res pirato ry and digestive,cardiovascular,locomoto r,urinary,and endocrine systems.This review provides new insights for the clinical treatment of nerve and multiple organ protection after spinal cord injury thanks to artificial hibernation.At present,artificial hibernation technology is not mature,and research fa ces various challenges.Neve rtheless,the effort is wo rthwhile for the future development of medicine.
基金supported by the National Natural Science Foundation of China(61601147)the Beijing Natural Science Foundation(L182032)。
文摘In this paper,an efficient unequal error protection(UEP)scheme for online fountain codes is proposed.In the buildup phase,the traversing-selection strategy is proposed to select the most important symbols(MIS).Then,in the completion phase,the weighted-selection strategy is applied to provide low overhead.The performance of the proposed scheme is analyzed and compared with the existing UEP online fountain scheme.Simulation results show that in terms of MIS and the least important symbols(LIS),when the bit error ratio is 10-4,the proposed scheme can achieve 85%and 31.58%overhead reduction,respectively.
基金supported by the National Natural Science Foundation of China(81703947)the Fundamental Research Funds for the Central Universities(2019-JYB-XJSJJ-011).
文摘Objective:To reveal the molecular mechanism underlying the compatibility of Salvia miltiorrhiza Bge(S.miltiorrhiza,Dan Shen)and C.tinctorius L.(C.tinctorius,Hong Hua)as an herb pair through network pharmacology and subsequent experimental validation.Methods:Network pharmacology was applied to construct an active ingredient-efficacy target-disease protein network to reveal the unique regulation pattern of s.miltiorrhiza and C.tinctorius as herb pair.Molecular docking was used to verify the binding of the components of these herbs and their potential targets.An H9c2 glucose hypoxia model was used to evaluate the efficacy of the components and their synergistic effects,which were evaluated using the combination index.Western blot was performed to detect the protein expression of these targets.Results:Network pharmacology analysis revealed 5 pathways and 8 core targets of s.miltiorrhiza and C.tinctorius in myocardial protection.Five of the core targets were enriched in the hypoxia-inducible factor-1(HIF-1)signaling pathway.S.miltiorrhiza-C.tinctorius achieved vascular tone mainly by regulating the target genes of the HIF-1 pathway.As an upstream gene of the HIF-1 pathway,STAT3 can be activated by the active ingredients cryptotanshinone(Ctan),salvianolic acid B(Sal.B),and myricetin(Myric).Cell experiments revealed that Myric,Sal.B,and Ctan also exhibited synergistic myocardial protective activity.Molecular docking verified the strong binding of Myric,Sal.B,and Ctan to STAT3.Western blot further showed that the active ingredients synergistically upregulated the protein expressionof STAT3.Conclusion:The pharmacodynamic transmission analysis revealed that the active ingredients of S.miltiorrhiza and C.tinctorius can synergistically resist ischemia through various targets and pathways.This study provides a methodological reference for interpreting traditional Chinese medicine compatibility.
基金supported by National Key R&D Program of China(Grant No.2020YFB1805403)Major Scientific and Technological Special Project of Guizhou Province(Grant No.20183001)+1 种基金Foundation of Guizhou Provincial Key Laboratory of Public Big Data(Grant Nos.2018BDKFJJ021,2018BDKFJJ020,2017BDKFJJ015,2018BDKFJJ008)the Fundamental Research Funds for the Central Universities(CUC210A003).
文摘The car-hailing platform based on Internet of Vehicles(IoV)tech-nology greatly facilitates passengers’daily car-hailing,enabling drivers to obtain orders more efficiently and obtain more significant benefits.However,to match the driver closest to the passenger,it is often necessary to process the location information of the passenger and driver,which poses a considerable threat to privacy disclosure to the passenger and driver.Targeting these issues,in this paper,by combining blockchain and Paillier homomorphic encryption algorithm,we design a secure blockchain-enabled IoV scheme with privacy protection for online car-hailing.In this scheme,firstly,we propose an encryp-tion scheme based on the lattice.Thus,the location information of passengers and drivers is encrypted in this system.Secondly,by introducing Paillier homomorphic encryption algorithm,the location matching of passengers and drivers is carried out in the ciphertext state to protect their location privacy.At last,blockchain technology is used to record the transactions in online car-hailing,which can provide a security guarantee for passengers and drivers.And we further analyze the security and performance of this scheme.Compared with other schemes,the experimental results show that the proposed scheme can protect the user’s location privacy and have a better performance.
基金supported by National Key R&D Program of China(No.2020YFC2006602)National Natural Science Foundation of China(Nos.62172324,62072324,61876217,6187612)+2 种基金University Natural Science Foundation of Jiangsu Province(No.21KJA520005)Primary Research and Development Plan of Jiangsu Province(No.BE2020026)Natural Science Foundation of Jiangsu Province(No.BK20190942).
文摘Most studies have conducted experiments on predicting energy consumption by integrating data formodel training.However, the process of centralizing data can cause problems of data leakage.Meanwhile,many laws and regulationson data security and privacy have been enacted, making it difficult to centralize data, which can lead to a datasilo problem. Thus, to train the model while maintaining user privacy, we adopt a federated learning framework.However, in all classical federated learning frameworks secure aggregation, the Federated Averaging (FedAvg)method is used to directly weight the model parameters on average, which may have an adverse effect on te model.Therefore, we propose the Federated Reinforcement Learning (FedRL) model, which consists of multiple userscollaboratively training the model. Each household trains a local model on local data. These local data neverleave the local area, and only the encrypted parameters are uploaded to the central server to participate in thesecure aggregation of the global model. We improve FedAvg by incorporating a Q-learning algorithm to assignweights to each locally uploaded local model. And the model has improved predictive performance. We validatethe performance of the FedRL model by testing it on a real-world dataset and compare the experimental results withother models. The performance of our proposed method in most of the evaluation metrics is improved comparedto both the centralized and distributed models.
基金supported in part by National Natural Science Foundation of China under Grant No.62172349,62032020,and 62172350the Research Foundation of Education Bureau of Hunan Province under Grant No.21B0139+1 种基金the National Key Research and Development Program of China under Grant 2021YFB3101200Hunan Science and Technology Planning Project under Grant No.2019RS3019.
文摘In edge computing,a reasonable edge resource bidding mechanism can enable edge providers and users to obtain benefits in a relatively fair fashion.To maximize such benefits,this paper proposes a dynamic multiattribute resource bidding mechanism(DMRBM).Most of the previous work mainly relies on a third-party agent to exchange information to gain optimal benefits.It isworth noting thatwhen edge providers and users trade with thirdparty agents which are not entirely reliable and trustworthy,their sensitive information is prone to be leaked.Moreover,the privacy protection of edge providers and users must be considered in the dynamic pricing/transaction process,which is also very challenging.Therefore,this paper first adopts a privacy protection algorithm to prevent sensitive information from leakage.On the premise that the sensitive data of both edge providers and users are protected,the prices of providers fluctuate within a certain range.Then,users can choose appropriate edge providers by the price-performance ratio(PPR)standard and the reward of lower price(LPR)standard according to their demands.The two standards can be evolved by two evaluation functions.Furthermore,this paper employs an approximate computing method to get an approximate solution of DMRBM in polynomial time.Specifically,this paper models the bidding process as a non-cooperative game and obtains the approximate optimal solution based on two standards according to the game theory.Through the extensive experiments,this paper demonstrates that the DMRBM satisfies the individual rationality,budget balance,and privacy protection and it can also increase the task offloading rate and the system benefits.
文摘A novel operation control method for relay protection in flexible DC distribution networks with distributed power supply is proposed to address the issue of inaccurate fault location during relay protection,leading to poor performance.The method combines a fault-tolerant fault location method based on long-term and short-term memory networks to accurately locate the fault section.Then,an operation control method for relay protection based on adaptive weight and whale optimization algorithm(WOA)is used to construct an objective function considering the shortest relay protection action time and the smallest impulse current.The adaptive weight and WOA are employed to obtain the optimal strategy for relay protection operation control,reducing the action time and impulse current.Experimental results demonstrate the effectiveness of the proposed method in accurately locating faults and improving relay protection performance.The longest operation time is reduced by 4.7023 s,and the maximum impulse current is limited to 0.3 A,effectively controlling the impact of large impulse currents and enhancing control efficiency.
基金supported by the National Natural Science Foundation of China-State Grid Joint Fund for Smart Grid(No.U2066210).
文摘The DC grid technology of multi-power supply and multi-drop-point power reception is an effective solution for large-scale renewable energy integration into the power grid.Line-commutated converter-Voltage source converter(LCC-VSC)power grids are one of the more important developmental directions of the future power grid that have occured in recent years.But the multi-terminal high voltage direct current system has the problems of inconsistent boundary characteristics,inconsistent control,and fault response characteristics,which puts higher requirements on the protection scheme.Thus,a completely new protection principle is proposed in this paper.Firstly,the fault characteristics of distributed capacitance current are analyzed.The reactive power calculated by the distribution parameters of different frequencies is different.Subsequently,the fault characteristics of DC reactive power are analyzed,and a DC reactive power extraction algorithm is proposed.The polarity of the multi-band DC reactive power is used to construct the protection scheme.Finally,the LCC-VSC power grid model verifies the correctness and superiority of the proposed protection scheme.The proposed scheme uses DC reactive power instead of fault current to solve the long delay problem caused by distributed capacitance.Compared with the prior art,the proposed solution is not affected by distributed capacitance and has a stronger anti-interference ability(600Ω+10 dB+1 ms).
基金supported by the National Natural Science Foundation of China-State Grid Joint Fund for Smart Grid(No.U2066210).
文摘Line-commutated converter-voltage source converter(LCC-VSC)power transmission technology does not have the problem of communication failure very usually.It therefore can support the long-distance,long-capacity transmission of electric energy.However,factors such as topology,control strategy,and short-circuit capacities make the traditional protection principles not fully applicable to LCC-VSC hybrid transmission systems.To enhance the reliability of hybrid DC systems,a single-ended principle based on transmission coefficients is proposed and produced.First,the equivalent circuit of the LCC-VSC hybrid DC system is analyzed and the expression of the first traveling wave is deduced accordingly.Then,the concept of multi-frequency transmission coefficients is proposed by analyzing the amplitude-frequency,and the characteristics of each element.Finally,the LCC-VSCDC system model is built to verify the reliability and superiority of the principle itself.Theoretical analysis and experimental verification show that the principle has strong interference resistance.
文摘In the current digital era, it is difficult to preserve the confidentiality, integrity, and availability of an organization’s information and technology assets against cyber attacks. Organizations cannot rely solely on technical solutions for defense, since many cyber attacks attempt to exploit non-technical vulnerabilities such as how well employees comply with the organization’s cybersecurity policies. This study surveyed 245 randomly selected employees of government organizations in the Kingdom of Saudi Arabia with an electronically distributed questionnaire about factors that influence employees’ compliance with cybersecurity policies. The study found that ethical factors had the most influence on employee compliance with cybersecurity policies, followed in decreasing order of influence by legislative factors, technical factors, and administrative factors.
文摘Under the epidemic situation of novel COVID-19 pneumonia, pregnant women belong to the susceptible population, and their physiological and psychological conditions are particularly worthy of attention. Diabetes patients during pregnancy may have a variety of complications, which can have a serious adverse impact on their own and fetal health. This article elaborates on home protection and diet and exercise guidance for pregnant women with diabetes in order to provide guidance for pregnant women with diabetes in a special period, and further prevent and control the pneumonia epidemic caused by novel COVID-19 infection in pregnant women.
基金financially supported by the National Natural Science Foundation of China(U22A20438)the National Key R&D Program of China(2022YFB2502100)the National Natural Science Foundation of China(22309138).
文摘Safety issue is still a problem nowadays for the large-scale application of lithium-ion batteries(LIBs)in electric vehicles and energy storage stations.The unsafe behaviors of LIBs arise from the thermal run-away,which is intrinsically triggered by the overcharging and overheating.To improve the safety of LIBs,various protection strategies based on self-actuating reaction control mechanisms(SRCMs)have been proposed,including redox shuttle,polymerizable monomer additive,potential-sensitive separator,thermal shutdown separator,positive-temperature-coefficient electrode,thermally polymerizable addi-tive,and reversible thermal phase transition electrolyte.As build-in protection mechanisms,these meth-ods can sensitively detect either the temperature change inside battery or the potential change of the electrode,and spontaneously shut down the electrode reaction at risky conditions,thus preventing the battery from going into thermal runaway.Given their advantages in enhancing the intrinsic safety of LIBs,this paper overviews the research progresses of SRCMs after a brief introduction of thermal runaway mechanism and limitations of conventional thermal runaway mitigating measures.More importantly,the current states and issues,key challenges,and future developing trends of SRCTs are also discussed and outlined from the viewpoint of practical application,aiming at providing insights and guidance for developing more effective SRCMs for LIBs.