Introduction: In 2016, China became the largest market for slim cigarettes in the world, selling 68.945 billion sticks. The purpose of this study is to examine the impact of China’s 2015 tobacco taxation policy on sl...Introduction: In 2016, China became the largest market for slim cigarettes in the world, selling 68.945 billion sticks. The purpose of this study is to examine the impact of China’s 2015 tobacco taxation policy on slim cigarette consumption and the product’s market trends. Methods: Monthly data on the market share of slim cigarettes and their average price between January 2014 and June 2017 were used to show tobacco market trends and to estimate the impact of the 2015 tobacco tax increase on tobacco consumption. Segmented regression analysis was used to estimate the immediate effect of the 2015 tax policy and the time trends in consumption due to the policy change. Findings: After the tobacco tax increase was announced in May 2015, the market share of slim cigarettes initially decreased by 0.2117 (p = 0.067). However, by the third month after the policy change, consumption began to increase, and the market share of slim cigarettes was 1.6 times the normal increase over time. Slim cigarettes gained a 2.02% additional share by the second quarter of 2017 (from 2.58% to 4.60%), controlling for the price difference between slim cigarettes and regular cigarettes. The coefficient of the share and the price ratio (slim cigarettes/regular cigarettes) was ?0.7536 (p = 0.0044), suggesting that slim cigarettes are a substitute for regular cigarettes. Estimates also show that after the tax increase was implemented, consumption of slim cigarettes increased almost three times the normal consumption rate (0.0069 versus 0.0024). Conclusion: The slim cigarette industry in China has grown rapidly in recent years. The 2015 tax increase has had only minimal or short-term impact on reducing the growing popularity of slim cigarettes. Since slim cigarettes are a substitute for regular cigarettes, more empirical research is urgently needed to study the health impacts of slim cigarette use and the impact of tobacco control policies on slim cigarette consumption.展开更多
In this work,two process-variation-tolerant schemes for a current-mode sense amplifier(CSA)of RRAM were proposed:(1)hybrid read reference generator(HRRG)that tracks process-voltage-temperature(PVT)variations and solve...In this work,two process-variation-tolerant schemes for a current-mode sense amplifier(CSA)of RRAM were proposed:(1)hybrid read reference generator(HRRG)that tracks process-voltage-temperature(PVT)variations and solve the nonlinear issue of the RRAM cells;(2)a two-stage offset-cancelled current sense amplifier(TSOCC-SA)with only two capacitors achieves a double sensing margin and a high tolerance of device mismatch.The simulation results in 28 nm CMOS technology show that the HRRG can provide a read reference that tracks PVT variations and solves the nonlinear issue of the RRAM cells.The proposed TSOCC-SA can tolerate over 64% device mismatch.展开更多
The tail bits of intermediate resistance states（IRSs） achieved in the SET process（IRSS） and the RESET process（IRSR） of conductive-bridge random-access memory were investigated. Two types of tail bits were observ...The tail bits of intermediate resistance states（IRSs） achieved in the SET process（IRSS） and the RESET process（IRSR） of conductive-bridge random-access memory were investigated. Two types of tail bits were observed, depending on the filament morphology after the SET/RESET operation.（i） Tail bits resulting from lateral diffusion of Cu ions introduced an abrupt increase of device resistance from IRS to ultrahigh-resistance state, which mainly happened in IRSS.（ii） Tail bits induced by the vertical diffusion of Cu ions showed a gradual shift of resistance toward lower value. Statistical results show that more than 95% of tail bits are generated in IRSS. To achieve a reliable IRS for multilevel cell（MLC） operation, it is desirable to program the IRS in RESET operation. The mechanism of tail bit generation that is disclosed here provides a clear guideline for the data retention optimization of MLC resistive random-access memory cells.展开更多
Many studies have indicated a relationship between smoking cessation and a history of depression. However, few studies have examined the association between smoking cessation and current depression and even fewer evid...Many studies have indicated a relationship between smoking cessation and a history of depression. However, few studies have examined the association between smoking cessation and current depression and even fewer evidence come from China's Mainland. The aim of this study is to determine the prevalence of smoking quitters, the correlates of successful smoking cessation, and its relationship with depressive symptoms in Northwest China. Methods: A total of 7,644 subjects who met the study’s entry criteria were randomly selected from the urban areas of three provinces in Northwest China and interviewed using standardized assessment tools, including basic characteristics of households and detailed information on family members. All respondents provided informed consent. Results: people with depression symptom have a more than 1.5-fold risk of abstinence from smoking than those without depression (OR=1.54;95% CI, 1.2 to 1.9) and the likelihood ratio test for two models reach statistical significance (x2=13.2, p<0.001). Smoking quitters have a more than 1.5-fold risk of having depressive symptoms than current smokers (OR=1.54;95% CI, 1.2 to 1.9) and the likelihood ratio test for two models is also statistically significant (x2=6449.85, p<0.001). Conclusions: The prevalence of smoking quitters in urban areas of Northwest China is very low. After controlling certain confounders, smoking cessation is associated with current depressive symptoms. More rigorous surveys are needed to elucidate the barriers to smoking cessation in China. Government bodies in China should implement appropriate strategies and execute effective measures to mitigate its harmful consequences.展开更多
The reservoir computing(RC)system,known for its ability to seamlessly integrate memory and computing functions,is considered as a promising solution to meet the high demands for time and energy-efficient computing in ...The reservoir computing(RC)system,known for its ability to seamlessly integrate memory and computing functions,is considered as a promising solution to meet the high demands for time and energy-efficient computing in the current big data landscape,compared with traditional silicon-based computing systems that have a noticeable disadvantage of separate storage and computation.This review focuses on in-materio RC based on nanowire networks(NWs)from the perspective of materials,extending to reservoir devices and applications.The common methods used in preparing nanowires-based reservoirs,including the synthesis of nanowires and the construction of networks,are firstly systematically summarized.The physical principles of memristive and memcapacitive junctions are then explained.Afterwards,the dynamic characteristics of nanowires-based reservoirs and their computing capability,as well as the neuromorphic applications of NWs-based RC systems in recognition,classification,and forecasting tasks,are explicated in detail.Lastly,the current challenges and future opportunities facing NWs-based RC are highlighted,aiming to provide guidance for further research.展开更多
China has achieved commendable success in stabilizing human immunodeficiency virus(HIV)prevalence at a relatively low level of transmission(1).Nevertheless,the total number of people living with HIV in China rose to a...China has achieved commendable success in stabilizing human immunodeficiency virus(HIV)prevalence at a relatively low level of transmission(1).Nevertheless,the total number of people living with HIV in China rose to approximately 1.05 million,with cumulative reported acquired immune deficiency syndrome(AIDS)-related fatalities reaching 351,000 by the end of 2020(2).Since the initial infiltration of HIV into China in 1982(3),the nation has enacted over 471 national policies through 2021 to combat the epidemic.Initially,the outbreak was perceived primarily as a healthcare issue rather than the complex societal challenge that it manifested into.The Ministry of Health(MOH,now known as National Health Commission)was initially tasked with HIV prevention,issuing the nation’s first HIV/AIDS-related policy in 1984,which aimed to ban HIV-infected products and individuals from entry.Regrettably,this approach proved inadequate as significant HIV outbreaks unfolded.At this juncture,the State Council Research Office recognized the HIV epidemic as a grave societal and public health issue,posing a threat to the“Survival of the Chinese Nation”(4).Engagement at a higher governmental level became imperative to coordinate an effective response across diverse administrative agencies.展开更多
Resistive random access memory(RRAM) has been considered as one of the most promising candidates for next-generation nonvolatile memory, due to its advantages of simple device structure, excellent scalability, fast op...Resistive random access memory(RRAM) has been considered as one of the most promising candidates for next-generation nonvolatile memory, due to its advantages of simple device structure, excellent scalability, fast operation speed and low power consumption. Deeply understanding the physical mechanism and effectively controlling the statistical variation of switching parameters are the basis of fostering RRAM into commercial application. In this paper, based on the deep understanding on the mechanism of the formation and rupture of conductive filament, we summarize the methods of analyzing and modeling the statistics of switching parameters such as SET/RESET voltage, current, speed or time. Then, we analyze the distributions of switching parameters and the influencing factors. Additionally, we also sum up the analytical model of resistive switching statistics composed of the cell-based percolation model and SET/RESET switching dynamics. The results of the model can successfully explain the experimental distributions of switching parameters of the Ni O- and Hf O2-based RRAM devices. The model also provides theoretical guide on how to improve the uniformity and reliability such as disturb immunity. Finally, some experimental approaches to improve the uniformity of switching parameters are discussed.展开更多
Crossbar array provides a cost-effective approach for achieving high-density integration of two-terminal functional devices. However, the ＂sneaking current problem＂, which can lead to read failure, is a severe chall...Crossbar array provides a cost-effective approach for achieving high-density integration of two-terminal functional devices. However, the ＂sneaking current problem＂, which can lead to read failure, is a severe challenge in crossbar arrays. To inhibit the sneaking current from unselected cells, the integration of individual selection devices is necessary. In this work, we report a novel TaOx-based selector exhibiting a trapezoidal band structure formed by tuning the concentration of defects in the oxide. Salient features such as a high current density （1 MA·cm^-2）, high selectivity （5 × 10^4）, low off-state current （-10 pA）, robust endurance （〉10^10）, self-compliance, and excellent uniformity were successfully achieved. The integrated one-selector one-resistor （1S1R） device exhibits high nonlinearity in the low resistance state （LRS）, which is quite effective in solving the sneaking current issue.展开更多
文摘Introduction: In 2016, China became the largest market for slim cigarettes in the world, selling 68.945 billion sticks. The purpose of this study is to examine the impact of China’s 2015 tobacco taxation policy on slim cigarette consumption and the product’s market trends. Methods: Monthly data on the market share of slim cigarettes and their average price between January 2014 and June 2017 were used to show tobacco market trends and to estimate the impact of the 2015 tobacco tax increase on tobacco consumption. Segmented regression analysis was used to estimate the immediate effect of the 2015 tax policy and the time trends in consumption due to the policy change. Findings: After the tobacco tax increase was announced in May 2015, the market share of slim cigarettes initially decreased by 0.2117 (p = 0.067). However, by the third month after the policy change, consumption began to increase, and the market share of slim cigarettes was 1.6 times the normal increase over time. Slim cigarettes gained a 2.02% additional share by the second quarter of 2017 (from 2.58% to 4.60%), controlling for the price difference between slim cigarettes and regular cigarettes. The coefficient of the share and the price ratio (slim cigarettes/regular cigarettes) was ?0.7536 (p = 0.0044), suggesting that slim cigarettes are a substitute for regular cigarettes. Estimates also show that after the tax increase was implemented, consumption of slim cigarettes increased almost three times the normal consumption rate (0.0069 versus 0.0024). Conclusion: The slim cigarette industry in China has grown rapidly in recent years. The 2015 tax increase has had only minimal or short-term impact on reducing the growing popularity of slim cigarettes. Since slim cigarettes are a substitute for regular cigarettes, more empirical research is urgently needed to study the health impacts of slim cigarette use and the impact of tobacco control policies on slim cigarette consumption.
基金supported in part by the National Key R&D Program of China under Grant No.2019YFB2204800in part by the Major Scientific Research Project of Zhejiang Lab(Grant No.2019KC0AD02)+1 种基金in part by the National Natural Science Foundation of China under Grants 61904200the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No.XDB44000000。
文摘In this work,two process-variation-tolerant schemes for a current-mode sense amplifier(CSA)of RRAM were proposed:(1)hybrid read reference generator(HRRG)that tracks process-voltage-temperature(PVT)variations and solve the nonlinear issue of the RRAM cells;(2)a two-stage offset-cancelled current sense amplifier(TSOCC-SA)with only two capacitors achieves a double sensing margin and a high tolerance of device mismatch.The simulation results in 28 nm CMOS technology show that the HRRG can provide a read reference that tracks PVT variations and solves the nonlinear issue of the RRAM cells.The proposed TSOCC-SA can tolerate over 64% device mismatch.
基金Project supported by the Ministry of Science and Technology of China(Grant Nos.2016YFA0203800,2016YFA0201803,and 2018YFB0407502)the National Natural Science Foundation of China(Grant Nos.61522408,61334007,and 61521064)+1 种基金Beijing Municipal Science&Technology Commission Program,China(Grant No.Z161100000216153)Huawei Data Center Technology Laboratory
文摘The tail bits of intermediate resistance states（IRSs） achieved in the SET process（IRSS） and the RESET process（IRSR） of conductive-bridge random-access memory were investigated. Two types of tail bits were observed, depending on the filament morphology after the SET/RESET operation.（i） Tail bits resulting from lateral diffusion of Cu ions introduced an abrupt increase of device resistance from IRS to ultrahigh-resistance state, which mainly happened in IRSS.（ii） Tail bits induced by the vertical diffusion of Cu ions showed a gradual shift of resistance toward lower value. Statistical results show that more than 95% of tail bits are generated in IRSS. To achieve a reliable IRS for multilevel cell（MLC） operation, it is desirable to program the IRS in RESET operation. The mechanism of tail bit generation that is disclosed here provides a clear guideline for the data retention optimization of MLC resistive random-access memory cells.
文摘Many studies have indicated a relationship between smoking cessation and a history of depression. However, few studies have examined the association between smoking cessation and current depression and even fewer evidence come from China's Mainland. The aim of this study is to determine the prevalence of smoking quitters, the correlates of successful smoking cessation, and its relationship with depressive symptoms in Northwest China. Methods: A total of 7,644 subjects who met the study’s entry criteria were randomly selected from the urban areas of three provinces in Northwest China and interviewed using standardized assessment tools, including basic characteristics of households and detailed information on family members. All respondents provided informed consent. Results: people with depression symptom have a more than 1.5-fold risk of abstinence from smoking than those without depression (OR=1.54;95% CI, 1.2 to 1.9) and the likelihood ratio test for two models reach statistical significance (x2=13.2, p<0.001). Smoking quitters have a more than 1.5-fold risk of having depressive symptoms than current smokers (OR=1.54;95% CI, 1.2 to 1.9) and the likelihood ratio test for two models is also statistically significant (x2=6449.85, p<0.001). Conclusions: The prevalence of smoking quitters in urban areas of Northwest China is very low. After controlling certain confounders, smoking cessation is associated with current depressive symptoms. More rigorous surveys are needed to elucidate the barriers to smoking cessation in China. Government bodies in China should implement appropriate strategies and execute effective measures to mitigate its harmful consequences.
基金financially supported by the National Key R&D Program of China(Grant No.2020AAA0109005)the Strategy Priority Research Program of Chinese Academy of Sciences(Grant No.XDA0330100)+1 种基金the Beijing Municipal Science&Technology Commission Program of China(Grant No.Z201100004320004)the China Association for Science and Technology(Grant No.2019Q1NRC001).
文摘The reservoir computing(RC)system,known for its ability to seamlessly integrate memory and computing functions,is considered as a promising solution to meet the high demands for time and energy-efficient computing in the current big data landscape,compared with traditional silicon-based computing systems that have a noticeable disadvantage of separate storage and computation.This review focuses on in-materio RC based on nanowire networks(NWs)from the perspective of materials,extending to reservoir devices and applications.The common methods used in preparing nanowires-based reservoirs,including the synthesis of nanowires and the construction of networks,are firstly systematically summarized.The physical principles of memristive and memcapacitive junctions are then explained.Afterwards,the dynamic characteristics of nanowires-based reservoirs and their computing capability,as well as the neuromorphic applications of NWs-based RC systems in recognition,classification,and forecasting tasks,are explicated in detail.Lastly,the current challenges and future opportunities facing NWs-based RC are highlighted,aiming to provide guidance for further research.
基金funded by grants from Hebei Social Sciences Fund,China(grant number:HB19GL026).
文摘China has achieved commendable success in stabilizing human immunodeficiency virus(HIV)prevalence at a relatively low level of transmission(1).Nevertheless,the total number of people living with HIV in China rose to approximately 1.05 million,with cumulative reported acquired immune deficiency syndrome(AIDS)-related fatalities reaching 351,000 by the end of 2020(2).Since the initial infiltration of HIV into China in 1982(3),the nation has enacted over 471 national policies through 2021 to combat the epidemic.Initially,the outbreak was perceived primarily as a healthcare issue rather than the complex societal challenge that it manifested into.The Ministry of Health(MOH,now known as National Health Commission)was initially tasked with HIV prevention,issuing the nation’s first HIV/AIDS-related policy in 1984,which aimed to ban HIV-infected products and individuals from entry.Regrettably,this approach proved inadequate as significant HIV outbreaks unfolded.At this juncture,the State Council Research Office recognized the HIV epidemic as a grave societal and public health issue,posing a threat to the“Survival of the Chinese Nation”(4).Engagement at a higher governmental level became imperative to coordinate an effective response across diverse administrative agencies.
基金supported by the National Natural Science Foundation of China(61322408,61221004,61334007,61274091,61106119 and 61106082)National Basic Research Program of China(2010CB934200 and 2011CBA00602)National High Technology Research and Development Program of China(2011AA010401 and 2011AA010402)
文摘Resistive random access memory(RRAM) has been considered as one of the most promising candidates for next-generation nonvolatile memory, due to its advantages of simple device structure, excellent scalability, fast operation speed and low power consumption. Deeply understanding the physical mechanism and effectively controlling the statistical variation of switching parameters are the basis of fostering RRAM into commercial application. In this paper, based on the deep understanding on the mechanism of the formation and rupture of conductive filament, we summarize the methods of analyzing and modeling the statistics of switching parameters such as SET/RESET voltage, current, speed or time. Then, we analyze the distributions of switching parameters and the influencing factors. Additionally, we also sum up the analytical model of resistive switching statistics composed of the cell-based percolation model and SET/RESET switching dynamics. The results of the model can successfully explain the experimental distributions of switching parameters of the Ni O- and Hf O2-based RRAM devices. The model also provides theoretical guide on how to improve the uniformity and reliability such as disturb immunity. Finally, some experimental approaches to improve the uniformity of switching parameters are discussed.
基金Acknowledgements This work was supported by the National Key Research and Development Program of China （Nos. 2016YFA0203800 and 2016YFA0201803） and the National Natural Science Foundation of China （No. 61522408）.
文摘Crossbar array provides a cost-effective approach for achieving high-density integration of two-terminal functional devices. However, the ＂sneaking current problem＂, which can lead to read failure, is a severe challenge in crossbar arrays. To inhibit the sneaking current from unselected cells, the integration of individual selection devices is necessary. In this work, we report a novel TaOx-based selector exhibiting a trapezoidal band structure formed by tuning the concentration of defects in the oxide. Salient features such as a high current density （1 MA·cm^-2）, high selectivity （5 × 10^4）, low off-state current （-10 pA）, robust endurance （〉10^10）, self-compliance, and excellent uniformity were successfully achieved. The integrated one-selector one-resistor （1S1R） device exhibits high nonlinearity in the low resistance state （LRS）, which is quite effective in solving the sneaking current issue.
