Artificial neural networks(ANN) have been extensively researched due to their significant energy-saving benefits.Hardware implementations of ANN with dropout function would be able to avoid the overfitting problem. Th...Artificial neural networks(ANN) have been extensively researched due to their significant energy-saving benefits.Hardware implementations of ANN with dropout function would be able to avoid the overfitting problem. This letter reports a dropout neuronal unit(1R1T-DNU) based on one memristor–one electrolyte-gated transistor with an ultralow energy consumption of 25 p J/spike. A dropout neural network is constructed based on such a device and has been verified by MNIST dataset, demonstrating high recognition accuracies(> 90%) within a large range of dropout probabilities up to40%. The running time can be reduced by increasing dropout probability without a significant loss in accuracy. Our results indicate the great potential of introducing such 1R1T-DNUs in full-hardware neural networks to enhance energy efficiency and to solve the overfitting problem.展开更多
Using the characteristic of addition of information quantity and the principle of equivalence of information quantity, this paper derives the general conversion formulae of the formation theory method conversion (synt...Using the characteristic of addition of information quantity and the principle of equivalence of information quantity, this paper derives the general conversion formulae of the formation theory method conversion (synthesis) on the systems consisting of different success failure model units. According to the fundamental method of the unit reliability assessment, the general models of system reliability approximate lower limits are given. Finally, this paper analyses the application of the assessment method by examples, the assessment results are neither conservative nor radical and very satisfactory. The assessment method can be popularized to the systems which have fixed reliability structural models.展开更多
1.——那是谁? ——是李雷。误:——Who's that? ——It's Li Lei. 正:——Who's that? That's Li Lei. 析:含有this,that作主语的疑问句中,当它们指物时,回答一般用it;但若指人时,回答时应保持不变,即仍用this或that...1.——那是谁? ——是李雷。误:——Who's that? ——It's Li Lei. 正:——Who's that? That's Li Lei. 析:含有this,that作主语的疑问句中,当它们指物时,回答一般用it;但若指人时,回答时应保持不变,即仍用this或that。2.——你的朋友是男孩还是女孩? ——男孩。误:——Is your friend a boy or a girl?展开更多
1.你能照看一下他们吗?误:Can you look after they?正:Can you look after them?析:英语里的人称代词共分两大类:I、you、he、she、we、they等是主格代词,在句子里通常用来作主语;me、you、him,her、us、them等是宾格代词,在句子里用...1.你能照看一下他们吗?误:Can you look after they?正:Can you look after them?析:英语里的人称代词共分两大类:I、you、he、she、we、they等是主格代词,在句子里通常用来作主语;me、you、him,her、us、them等是宾格代词,在句子里用作行为动词或介词的宾语。此例里“他们”是look after的宾语,故只能用宾格代词。展开更多
1.问:“What's in the teacher's room?”一句中的两个“'s”用法一样吗? 答:句中的这两个“'s”用法不同。What's是What is的缩略形式,这个“'s”意为“是”。teacher's不是teacher is的缩略形式,这个“&#...1.问:“What's in the teacher's room?”一句中的两个“'s”用法一样吗? 答:句中的这两个“'s”用法不同。What's是What is的缩略形式,这个“'s”意为“是”。teacher's不是teacher is的缩略形式,这个“'s”展开更多
1.你想拿回你的电视机,对吗? 误:You want to get your TV set back,aren't you? 误:You want to get your TV set back.do vou? 正:You want to get your TV set back,don't you? 析:英语中,want是行为动词,其反意部分要用助动...1.你想拿回你的电视机,对吗? 误:You want to get your TV set back,aren't you? 误:You want to get your TV set back.do vou? 正:You want to get your TV set back,don't you? 析:英语中,want是行为动词,其反意部分要用助动词do来构成,不能用are。另外,反意疑问句中若前面部分是肯定的。展开更多
Solid polymer electrolytes have been considered as the promising candidates to improve the safety and stability of high-energy lithium metal batteries.However,the practical applications of solid polymer electrolytes a...Solid polymer electrolytes have been considered as the promising candidates to improve the safety and stability of high-energy lithium metal batteries.However,the practical applications of solid polymer electrolytes are still limited by the low ionic conductivity,poor interfacial contact with electrodes,narrow electrochemical window and weak mechanical strength.Here,a series of novel block copolymer electrolytes with three-dimensional networks are designed by cross-linked copolymerization of the polyethylene glycol soft segments and hexamethylene diisocyanate trimer hard segments.Their ionic migration performances and interface compatibilities with Li metal anode have been optimized delicately by tailoring the ratio of these functional units.The optimized block copolymer electrolyte has shown an amorphous crystalline structure,a high ionic conductivity of ~5.7×10^(-4)S cm^(-1),high lithium ion transference number(~0.49),wide electrochemical window up to ~4.65 V(vs.Li+/Li) and favorable mechanical strength at 55℃.Furthermore,the enhanced interface compatibility can well support the normal operations of lithium metal batteries using both LiFePO4 and LiNi0.8Co0.15Al0.05O2 cathodes.This study not only paves a new way to develop solid polymer electrolyte with optimizing functional units,but also provides a polymer electrolyte design strategy for the application demand of lithium metal battery.展开更多
Escalating apprehension about the harmful effects of widespread use of conventional fossil fuels in the marine field and in internal combustion engines in general, has led to a vast amount of efforts and the directing...Escalating apprehension about the harmful effects of widespread use of conventional fossil fuels in the marine field and in internal combustion engines in general, has led to a vast amount of efforts and the directing of large capital investment towards research and development of sustainable alternative energy sources. One of the most promising and abundant of these sources is hydrogen. Firstly, the use of current fossil fuels is. discussed focusing on the emissions and economic sides to emphasize the need for a new, cleaner and renewable fuel with particular reference to hydrogen as a suitable possible alternative. Hydrogen properties, production and storage methods are then reviewed along with its suitability from the economical point of view. Finally, a cost analysis for the use of hydrogen in internal combustion engines is carried out to illustrate the benefits of its use as a replacement for diesel. The outcome of this cost analysis shows that 98% of the capital expenditure is consumed by the equipment, and 68.3% of the total cost of the equipment is spent on the solar photovoltaic cells. The hydrogen plant is classified as a large investment project because of its high initial cost which is about 1 billion US$; but this is justified because hydrogen is produced in a totally green way. When hydrogen is used as a fuel, no harmful emissions are obtained.展开更多
Based on the data associated with cores,sidewall cores,casting thin sections,reservoir physical properties,conventional logging and imaging logging,the classification schemes of vertical reservoir units are proposed f...Based on the data associated with cores,sidewall cores,casting thin sections,reservoir physical properties,conventional logging and imaging logging,the classification schemes of vertical reservoir units are proposed for the two types of Archaeozoic buried hills(exposed and covered ones)in the Bozhong Sag,Bohai Bay Basin.The geological characteristics and storage spaces of these reservoir units are described,and their identification markers in conventional and imaging log curves are established.The Archaeozoic metamorphic buried hills can be vertically classified into two primary reservoir units:weathering crust and inner buried hill.The weathering crust contains four secondary units,i.e.,the clay zone,weathered glutenite zone,leached zone,disaggregation zone;and the interiors contain two secondary units,i.e.,interior fracture zone and tight zone.In particular,the inner fracture zone was further divided into cataclasite belts and dense-fracture belts.It is proposed that the favorable reservoirs of exposed Archaeozoic metamorphic buried hills are mainly developed in four parts including weathered glutenite zone,leached zone,disintegration zone superposed with the cataclasite belt and the cataclasite belt of inner fracture zone,and are controlled by both weathering and tectonic actions.Favorable reservoirs in covered Archaeozoic metamorphic buried hills are mainly developed in the weathering crust superposed with the cataclasite belts and the cataclasite belts of inner fracture zone,and are mainly controlled by tectonic actions.展开更多
Once operating trains are disabled on the railway lines,an efficient manner is to utilize the train for train rescue.Owning to the different train and coupler types,it is difficult to formulate uniform regulations for...Once operating trains are disabled on the railway lines,an efficient manner is to utilize the train for train rescue.Owning to the different train and coupler types,it is difficult to formulate uniform regulations for train to train rescue.In this paper,the longitudinal train dynamics of electric multiple units under rescue were analyzed by field and laboratory tests.The angling behavior of the brakinginduced coupler under compressed in-train forces was analyzed.A dynamic model for the train and draft gear system was developed considering accurate boundary limitations and braking characteristics.The safety indices and their limits for the coupled rescue train were defined.Thedynamic evaluations of different train to train rescue scenarios were analyzed.It is indicated that the coupler vertical rotation occurs during the emergency braking applied by the assisting train.The vertical force components of intrain forces lead to the carbody pitch behavior and even cause local destructions to the coupler system.The carbody pitch motion can arise the inference of in-train devices.Based on the safety evaluation of train and coupler system,the regulations for typical train to train rescue scenarios were formulated.展开更多
Background Little information exists about the role of anemia in patients with acute coronary syndromes(ACS)admitted to Intensive Cardiac Care Units(ICCU).The aim of this study was to assess the prevalence of anemia a...Background Little information exists about the role of anemia in patients with acute coronary syndromes(ACS)admitted to Intensive Cardiac Care Units(ICCU).The aim of this study was to assess the prevalence of anemia and its impact on management and outcomes in this clinical setting.Methods All consecutive patients admitted to eight different ICCUs with diagnosis of non-ST segment elevation ACS(NSTEACS)were prospectively included.Anemia was defined as hemoglobin<130 g/L in men and<120 g/L in women.The association between anemia and mortality or readmission at six months was assessed by the Cox regression method.Results A total of 629 patients were included.Mean age was 66.6 years.A total of 197 patients(31.3%)had anemia.Coronary angiography was performed in most patients(96.2%).Patients with anemia were significantly older,with a higher prevalence of comorbidities,poorer left ventricle ejection fraction and higher GRACE score values.Patients with anemia underwent less often coronary angiography,but underwent more often intraaortic counterpulsation,non-invasive mechanical ventilation and renal replacement therapies.Both ICCU and hospital stay were significantly longer in patients with anemia.Both the incidence of mortality(HR=3.36,95%CI:1.43–7.85,P=0.001)and the incidence of mortality/readmission were significantly higher in patients with anemia(HR=2.80,95%CI:2.03–3.86,P=0.001).After adjusting for confounders,the association between anemia and mortality/readmission remained significant(P=0.031).Conclusions Almost one of three NSTEACS patients admitted to ICCU had anemia.Most patients underwent coronary angiography.Anemia was independently associated to poorer outcomes at 6 months.展开更多
Attention is concentrated on how to perform the innovative design during the process of pumping unit conceptual design, and how to enhance design efficiency and inspire creativity. Aiming at the shortages of conceptua...Attention is concentrated on how to perform the innovative design during the process of pumping unit conceptual design, and how to enhance design efficiency and inspire creativity. Aiming at the shortages of conceptual design, introducing the theory of inventive problem solving （TRIZ） into the mechanical product design for producing innovative ideas, and using the advanced computer-aided technique, the intelligent decision support system （IDSS） based on TRIZ （TRIZ-IDSS） has been constructed. The construction method, system structure, conceptual production, decisionmaking and evaluation of the problem solving subsystem are discussed. The innovative conceptual design of pumping units indicates that the system can help the engineers open up a new space of thinking, overcome the thinking inertia, and put forward innovative design concepts. This system also can offer the scientific instructions for the innovative design of mechanical products.展开更多
High-dependency units(HDUs)provide high-level care to patients who suffer from single organ failure,with the exception of respiratory failure requiring mechanical ventilation;HDUs serve as an intermediary between gene...High-dependency units(HDUs)provide high-level care to patients who suffer from single organ failure,with the exception of respiratory failure requiring mechanical ventilation;HDUs serve as an intermediary between general wards and Intensive Care Units.Due to military and civilian needs,our hospital has established a unique HDU for patients with liver disease in China.A Chinese military officer in the United Nations Peacekeeping Forces in South Sudan was transferred to our HDU for liver failure treatment in 2018.The patient’s disease status,nutrition,sleep habits,and psychological behaviour were monitored on different scales.The patient was provided with vascular monitoring,telemetry,pulse oximetry,drug treatment,nutritional support,sleep intervention,psychological intervention,and humanistic care by a multidisciplinary treatment team.After treatment,the patient recovered and avoided liver transplantation.Based on the experience with this HDU,this new model may create an efficient treatment process for military and civilian patients with severe liver disease at home or abroad.展开更多
The South African gold mining sector remains a significant contributor to the country’s economy.Facing several challenges that hinder the realisation of South Africa’s full mineral potential,the sector’s sustainabi...The South African gold mining sector remains a significant contributor to the country’s economy.Facing several challenges that hinder the realisation of South Africa’s full mineral potential,the sector’s sustainability and profitability can be enhanced through implementing operational improvement measures.Mobile cooling units(MCUs)were identified as a potential focus area for operational improvement.MCUs are used as tertiary or in-stope cooling in hot underground workings.In this paper,a method was presented to characterise the performance of existing MCUs based on three key performance indicators(KPIs),namely,the wet-bulb temperature ratio(WTR),efficiency and position.Optimisation strategies were then elected and implemented based on these KPIs.The implementation of this method in a South African gold mine attained a reduction in pumped water volumes,reduced operating costs through electricity cost savings and improvements in underground ventilation air temperatures.展开更多
基金Project supported by the National Key Research and Development Program of China (Grant Nos. 2021YFA1202600 and 2023YFE0208600)in part by the National Natural Science Foundation of China (Grant Nos. 62174082, 92364106, 61921005, 92364204, and 62074075)。
文摘Artificial neural networks(ANN) have been extensively researched due to their significant energy-saving benefits.Hardware implementations of ANN with dropout function would be able to avoid the overfitting problem. This letter reports a dropout neuronal unit(1R1T-DNU) based on one memristor–one electrolyte-gated transistor with an ultralow energy consumption of 25 p J/spike. A dropout neural network is constructed based on such a device and has been verified by MNIST dataset, demonstrating high recognition accuracies(> 90%) within a large range of dropout probabilities up to40%. The running time can be reduced by increasing dropout probability without a significant loss in accuracy. Our results indicate the great potential of introducing such 1R1T-DNUs in full-hardware neural networks to enhance energy efficiency and to solve the overfitting problem.
文摘Using the characteristic of addition of information quantity and the principle of equivalence of information quantity, this paper derives the general conversion formulae of the formation theory method conversion (synthesis) on the systems consisting of different success failure model units. According to the fundamental method of the unit reliability assessment, the general models of system reliability approximate lower limits are given. Finally, this paper analyses the application of the assessment method by examples, the assessment results are neither conservative nor radical and very satisfactory. The assessment method can be popularized to the systems which have fixed reliability structural models.
文摘1.——那是谁? ——是李雷。误:——Who's that? ——It's Li Lei. 正:——Who's that? That's Li Lei. 析:含有this,that作主语的疑问句中,当它们指物时,回答一般用it;但若指人时,回答时应保持不变,即仍用this或that。2.——你的朋友是男孩还是女孩? ——男孩。误:——Is your friend a boy or a girl?
文摘1.你能照看一下他们吗?误:Can you look after they?正:Can you look after them?析:英语里的人称代词共分两大类:I、you、he、she、we、they等是主格代词,在句子里通常用来作主语;me、you、him,her、us、them等是宾格代词,在句子里用作行为动词或介词的宾语。此例里“他们”是look after的宾语,故只能用宾格代词。
文摘1.你想拿回你的电视机,对吗? 误:You want to get your TV set back,aren't you? 误:You want to get your TV set back.do vou? 正:You want to get your TV set back,don't you? 析:英语中,want是行为动词,其反意部分要用助动词do来构成,不能用are。另外,反意疑问句中若前面部分是肯定的。
基金supported financially by the National Key R&D Program of China (Grant No. 2018YFB0104300)Beijing Natural Science Foundation (JQ19003, KZ201910005002 and L182009)+1 种基金National Natural Science Foundation of China (Grants 21875007, 51622202, and 21974007)the Project of Youth Talent Plan of Beijing Municipal Education Commission (CIT&TCD201804013)。
文摘Solid polymer electrolytes have been considered as the promising candidates to improve the safety and stability of high-energy lithium metal batteries.However,the practical applications of solid polymer electrolytes are still limited by the low ionic conductivity,poor interfacial contact with electrodes,narrow electrochemical window and weak mechanical strength.Here,a series of novel block copolymer electrolytes with three-dimensional networks are designed by cross-linked copolymerization of the polyethylene glycol soft segments and hexamethylene diisocyanate trimer hard segments.Their ionic migration performances and interface compatibilities with Li metal anode have been optimized delicately by tailoring the ratio of these functional units.The optimized block copolymer electrolyte has shown an amorphous crystalline structure,a high ionic conductivity of ~5.7×10^(-4)S cm^(-1),high lithium ion transference number(~0.49),wide electrochemical window up to ~4.65 V(vs.Li+/Li) and favorable mechanical strength at 55℃.Furthermore,the enhanced interface compatibility can well support the normal operations of lithium metal batteries using both LiFePO4 and LiNi0.8Co0.15Al0.05O2 cathodes.This study not only paves a new way to develop solid polymer electrolyte with optimizing functional units,but also provides a polymer electrolyte design strategy for the application demand of lithium metal battery.
文摘Escalating apprehension about the harmful effects of widespread use of conventional fossil fuels in the marine field and in internal combustion engines in general, has led to a vast amount of efforts and the directing of large capital investment towards research and development of sustainable alternative energy sources. One of the most promising and abundant of these sources is hydrogen. Firstly, the use of current fossil fuels is. discussed focusing on the emissions and economic sides to emphasize the need for a new, cleaner and renewable fuel with particular reference to hydrogen as a suitable possible alternative. Hydrogen properties, production and storage methods are then reviewed along with its suitability from the economical point of view. Finally, a cost analysis for the use of hydrogen in internal combustion engines is carried out to illustrate the benefits of its use as a replacement for diesel. The outcome of this cost analysis shows that 98% of the capital expenditure is consumed by the equipment, and 68.3% of the total cost of the equipment is spent on the solar photovoltaic cells. The hydrogen plant is classified as a large investment project because of its high initial cost which is about 1 billion US$; but this is justified because hydrogen is produced in a totally green way. When hydrogen is used as a fuel, no harmful emissions are obtained.
基金Supported by the National Natural Science Foundation of China(41790453,41972313).
文摘Based on the data associated with cores,sidewall cores,casting thin sections,reservoir physical properties,conventional logging and imaging logging,the classification schemes of vertical reservoir units are proposed for the two types of Archaeozoic buried hills(exposed and covered ones)in the Bozhong Sag,Bohai Bay Basin.The geological characteristics and storage spaces of these reservoir units are described,and their identification markers in conventional and imaging log curves are established.The Archaeozoic metamorphic buried hills can be vertically classified into two primary reservoir units:weathering crust and inner buried hill.The weathering crust contains four secondary units,i.e.,the clay zone,weathered glutenite zone,leached zone,disaggregation zone;and the interiors contain two secondary units,i.e.,interior fracture zone and tight zone.In particular,the inner fracture zone was further divided into cataclasite belts and dense-fracture belts.It is proposed that the favorable reservoirs of exposed Archaeozoic metamorphic buried hills are mainly developed in four parts including weathered glutenite zone,leached zone,disintegration zone superposed with the cataclasite belt and the cataclasite belt of inner fracture zone,and are controlled by both weathering and tectonic actions.Favorable reservoirs in covered Archaeozoic metamorphic buried hills are mainly developed in the weathering crust superposed with the cataclasite belts and the cataclasite belts of inner fracture zone,and are mainly controlled by tectonic actions.
基金supported by the National Natural Science Foundation of China [No.U1334206]the National Key R&D Program of China [No.2016YFB1200500]
文摘Once operating trains are disabled on the railway lines,an efficient manner is to utilize the train for train rescue.Owning to the different train and coupler types,it is difficult to formulate uniform regulations for train to train rescue.In this paper,the longitudinal train dynamics of electric multiple units under rescue were analyzed by field and laboratory tests.The angling behavior of the brakinginduced coupler under compressed in-train forces was analyzed.A dynamic model for the train and draft gear system was developed considering accurate boundary limitations and braking characteristics.The safety indices and their limits for the coupled rescue train were defined.Thedynamic evaluations of different train to train rescue scenarios were analyzed.It is indicated that the coupler vertical rotation occurs during the emergency braking applied by the assisting train.The vertical force components of intrain forces lead to the carbody pitch behavior and even cause local destructions to the coupler system.The carbody pitch motion can arise the inference of in-train devices.Based on the safety evaluation of train and coupler system,the regulations for typical train to train rescue scenarios were formulated.
文摘Background Little information exists about the role of anemia in patients with acute coronary syndromes(ACS)admitted to Intensive Cardiac Care Units(ICCU).The aim of this study was to assess the prevalence of anemia and its impact on management and outcomes in this clinical setting.Methods All consecutive patients admitted to eight different ICCUs with diagnosis of non-ST segment elevation ACS(NSTEACS)were prospectively included.Anemia was defined as hemoglobin<130 g/L in men and<120 g/L in women.The association between anemia and mortality or readmission at six months was assessed by the Cox regression method.Results A total of 629 patients were included.Mean age was 66.6 years.A total of 197 patients(31.3%)had anemia.Coronary angiography was performed in most patients(96.2%).Patients with anemia were significantly older,with a higher prevalence of comorbidities,poorer left ventricle ejection fraction and higher GRACE score values.Patients with anemia underwent less often coronary angiography,but underwent more often intraaortic counterpulsation,non-invasive mechanical ventilation and renal replacement therapies.Both ICCU and hospital stay were significantly longer in patients with anemia.Both the incidence of mortality(HR=3.36,95%CI:1.43–7.85,P=0.001)and the incidence of mortality/readmission were significantly higher in patients with anemia(HR=2.80,95%CI:2.03–3.86,P=0.001).After adjusting for confounders,the association between anemia and mortality/readmission remained significant(P=0.031).Conclusions Almost one of three NSTEACS patients admitted to ICCU had anemia.Most patients underwent coronary angiography.Anemia was independently associated to poorer outcomes at 6 months.
文摘Attention is concentrated on how to perform the innovative design during the process of pumping unit conceptual design, and how to enhance design efficiency and inspire creativity. Aiming at the shortages of conceptual design, introducing the theory of inventive problem solving （TRIZ） into the mechanical product design for producing innovative ideas, and using the advanced computer-aided technique, the intelligent decision support system （IDSS） based on TRIZ （TRIZ-IDSS） has been constructed. The construction method, system structure, conceptual production, decisionmaking and evaluation of the problem solving subsystem are discussed. The innovative conceptual design of pumping units indicates that the system can help the engineers open up a new space of thinking, overcome the thinking inertia, and put forward innovative design concepts. This system also can offer the scientific instructions for the innovative design of mechanical products.
文摘High-dependency units(HDUs)provide high-level care to patients who suffer from single organ failure,with the exception of respiratory failure requiring mechanical ventilation;HDUs serve as an intermediary between general wards and Intensive Care Units.Due to military and civilian needs,our hospital has established a unique HDU for patients with liver disease in China.A Chinese military officer in the United Nations Peacekeeping Forces in South Sudan was transferred to our HDU for liver failure treatment in 2018.The patient’s disease status,nutrition,sleep habits,and psychological behaviour were monitored on different scales.The patient was provided with vascular monitoring,telemetry,pulse oximetry,drug treatment,nutritional support,sleep intervention,psychological intervention,and humanistic care by a multidisciplinary treatment team.After treatment,the patient recovered and avoided liver transplantation.Based on the experience with this HDU,this new model may create an efficient treatment process for military and civilian patients with severe liver disease at home or abroad.
基金This work was sponsored by ETA Operations(Pty)Ltd.
文摘The South African gold mining sector remains a significant contributor to the country’s economy.Facing several challenges that hinder the realisation of South Africa’s full mineral potential,the sector’s sustainability and profitability can be enhanced through implementing operational improvement measures.Mobile cooling units(MCUs)were identified as a potential focus area for operational improvement.MCUs are used as tertiary or in-stope cooling in hot underground workings.In this paper,a method was presented to characterise the performance of existing MCUs based on three key performance indicators(KPIs),namely,the wet-bulb temperature ratio(WTR),efficiency and position.Optimisation strategies were then elected and implemented based on these KPIs.The implementation of this method in a South African gold mine attained a reduction in pumped water volumes,reduced operating costs through electricity cost savings and improvements in underground ventilation air temperatures.
