Gate-grounded n-channel metal-oxide-semiconductor(GGNMOS)devices have been widely implemented as power clamps to protect semiconductor devices from electrostatic discharge stress owing to their simple construction,eas...Gate-grounded n-channel metal-oxide-semiconductor(GGNMOS)devices have been widely implemented as power clamps to protect semiconductor devices from electrostatic discharge stress owing to their simple construction,easy triggering,and low power dissipation.We present a novel I-V characterization of the GGNMOS used as the power clamp in complementary metal-oxide-semiconductor circuits as a result of switching the ESD paths under different impact energies.This special effect could cause an unexpected latch-up or pre-failure phenomenon in some applications with relatively large capacitances from power supply to power ground,and thus should be urgently analyzed and resolved.Transmission-linepulse,human-body-modal,and light-emission tests were performed to explore the root cause.展开更多
To solve the problem of long response time when users obtain suitable cutting parameters through the Internet based platform,a case-based reasoning framework is proposed.Specifically,a Hamming distance and Euclidean d...To solve the problem of long response time when users obtain suitable cutting parameters through the Internet based platform,a case-based reasoning framework is proposed.Specifically,a Hamming distance and Euclidean distance combined method is designed to measure the similarity of case features which have both numeric and category properties.In addition,AHP(Analytic Hierarchy Process)and entropy weight method are integrated to provide features weight,where both user preferences and comprehensive impact of the index have been concerned.Grey relation analysis is used to obtain the similarity of a new problem and alternative cases.Finally,a platform is also developed on Visual Studio 2015,and a case study is demonstrated to verify the practicality and efficiency of the proposed method.This method can obtain cutting parameters which is suitable without iterative calculation.Compared with the traditional PSO(Particle swarm optimization algorithm)and GA(Genetic algorithm),it can obtain faster response speed.This method can provide ideas for selecting processing parameters in industrial production.While guaranteeing the characteristic information is similar,this approach can select processing parameters which is the most appropriate for the production process and a lot of time can be saved.展开更多
Due to the diversity of work requirements and environment,the number of degrees of freedom(DOFs)and the complexity of structure of industrial robots are constantly increasing.It is difficult to establish the accurate ...Due to the diversity of work requirements and environment,the number of degrees of freedom(DOFs)and the complexity of structure of industrial robots are constantly increasing.It is difficult to establish the accurate dynamical model of industrial robots,which greatly hinders the realization of a stable,fast and accurate trajectory tracking control.Therefore,the general expression of the constraint relation in the explicit dynamic equation of the multi-DOF industrial robot is derived on the basis of solving the Jacobian matrix and Hessian matrix by using the kinematic influence coefficients method.Moreover,an explicit dynamic equation with general constraint relation expression is established based on the Udwadia-Kalaba theory.The problem of increasing the time of establishing constraint relationship when the multi-DOF industrial robots complete complex task constraints is solved.With the SCARA robot as the research object,the simulation results show that the proposed method can provide a new idea for industrial robot system modeling with complex constraints.展开更多
Extreme space weather events including≥X5.0 flares,ground level enhancement(GLE)events and super geomagnetic storms(Dst≥-250 nT)caused by super active regions(SARs)during solar cycles 21-24 were studied.The total nu...Extreme space weather events including≥X5.0 flares,ground level enhancement(GLE)events and super geomagnetic storms(Dst≥-250 nT)caused by super active regions(SARs)during solar cycles 21-24 were studied.The total number ofX5.0 solar flares was 62,among which 41 were X5.0-X9.9 flares and 21 were≥X10.0 flares.We found that 83.9%of the≥X5.0 flares were produced by SARs;78.05%of the X5.0-X9.9 and 95.24%of the≥X10.0 solar flares were produced by SARs;46 GLEs were registered during solar cycles 21-24,and 25 GLEs were caused by SARs,indicating that 54.3%of the GLEs were caused by SARs;24 super geomagnetic storms were recorded during solar cycles 21-24,and 12 of them were caused by SARs,namely 50%of the super geomagnetic storms were caused by SARs.We ascertained that only 29 SARs produced≥X5.0 flares,15 SARs generated GLEs and 10 SARs triggered super geomagnetic storms.Of the 51 SARs,only 33 SARs produced at least one extreme space weather event,while none of the other 18 SARs could trigger an extreme space weather event.There were only four SARs and each of them generated not only a≥X5.0 flare,but also a GLE event and a super geomagnetic storm.Most of the extreme space weather events caused by the SARs appeared during solar cycles 22 and 23,especially for GLE events and super geomagnetic storms.The longitudinal distributions of source locations for the extreme space weather events caused by SARs were also studied.展开更多
A new low power, low phase jitter, compact realization, and sell-biased PLL, which is fabricated on SMIC 40 nm CMOS technology is introduced. The proposed self-biased PLL eliminates extra band gap biasing circuits, an...A new low power, low phase jitter, compact realization, and sell-biased PLL, which is fabricated on SMIC 40 nm CMOS technology is introduced. The proposed self-biased PLL eliminates extra band gap biasing circuits, and internally generates all the biasing voltages and currents. Meanwhile, all of the PLL dynamic loop parameters, such as loop bandwidth, natural frequency, damping factors are kept constant adaptively. By optimizing the circuit structures, the perfect unity of chip estate, power dissipation, phase jitter, and loop stability is achieved. THe PLL consumes 4.2 mW of power tinder 1.1 V/2.5 V voltage supply at 2.4 GHz VCO frequency, while occupying a die area of less than 0.02 mmz （180 × 110 μm2）, and the typical period jitter （RMS） is around 2.8 ps.展开更多
Background:Primary dysmenorrhea(PD)is the most common complaint associated with menstruation and affects up to three-quarters of women at some stage of their reproductive life.In Chinese medicine,navel therapy,treatme...Background:Primary dysmenorrhea(PD)is the most common complaint associated with menstruation and affects up to three-quarters of women at some stage of their reproductive life.In Chinese medicine,navel therapy,treatment provided at Shenque(CV 8),is used as a treatment option for PD.Objective:To evaluate the effect of navel therapy on pain relief and quality of life in women with PD,compared with Western medicine(WM).Methods:China National Knowledge Infrastructure(CNKI),Chinese Scientific Journal Database(VIP),Sino Med and Wanfang Database,MEDLINE,the Cochrane Library,Embase,Web of Science,and the International Clinical Trial Registry of the U.S.National Institutes of Health were searched from their inceptions to April 1,2021.Randomized controlled trials(RCTs)assessing therapeutic effects of navel therapy on PD were eligible for inclusion.Rev Man 5.4 software was used for data analyses.The certainty of the evidence was assessed using the online GRADEpro tool.Results:Totally 24 RCTs involving 2,614 participants were identified.Interventions applied to acupuncture point CV 8 included:herbal patching,moxibustion or combined navel therapy(using at least 2 types of stimulation).Compared to placebo,there was a significant effect in favor of navel therapy on reducing overall menstrual symptom scores at the end of treatment[mean difference:-0.82,95%confidence interval(CI):-1.00 to-0.64,n=90;1 RCT].As compared with Western medicine,navel therapy had a superior effect on pain intensity as assessed by Visual Analogue Scale at the end of treatment[standardized mean difference(SMD):-0.64,95%CI:-1.22 to-0.06,I^(2)=80%,n=262;3 RCTs];on symptom resolution rate at 3-month follow-up(risk ratio:1.94,95%CI:1.47 to 2.56,n=1527,I^(2)=38%;13 RCTs);and on global menstrual symptoms score at the end of treatment(SMD:-0.67,95%CI:-0.90 to-0.45,I^(2)=63%,n=990;12 RCTs).Subgroup analyses showed either a better or an equivalent effect comparing navel therapy with Western medicine.No major adverse events were reported.The methodological quality of included trials was poor overall.Conclusions:Navel therapy appears to be more effective than Western medicine in decreasing menstrual pain and improving overall symptoms of PD.However,these findings need to be confirmed by well-designed clinical trials with adequate sample size(Systematic review registration at PROSPERO,No.CRD42021240350).展开更多
It is still a huge challenge to introduce effective crack-healing ability into energetic composites with a high oxidizer content.In this article,a poly(urea-urethane)energetic elastomer was prepared by the polycondens...It is still a huge challenge to introduce effective crack-healing ability into energetic composites with a high oxidizer content.In this article,a poly(urea-urethane)energetic elastomer was prepared by the polycondensation reaction of glycidyl azido polymer(GAP),isophorone diisocyanate(IPDI),and 2-aminophenyl disulfide(2-APD).In the poly(urea-urethane)elastomer structure,the hybrid dynamic lock,including multilevel H-bonds and disulfide bonds,not only provides abundant dynamic interactions and promotes chain diffusion,but also enhances physical crosslinking density.Such a unique design fabricated the energetic elastomer with robust tensile strength(0.72MPa),high stretchability(1631%),and outstanding toughness(8.95MJ/m 3)in the field of energetic polymers.Meanwhile,this energetic elastomer exhibited high self-healing efficiency(98.4%at 60°C)and heat release(Q=1750.46J/g).Experimental and theoretical results adequately explain the self-healing mechanism,particularly the role of azido units.The high-solid content(80wt%)energetic composites based on the energetic elastomer presented outstanding micro-defect self-healing(97.8%)and recycling without loss of mechanical performance.The development of smart energetic composites with excellent self-healing and recyclable ability provides a meaningful way for a wide range of applications in the field of energetic materials.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61974017)。
文摘Gate-grounded n-channel metal-oxide-semiconductor(GGNMOS)devices have been widely implemented as power clamps to protect semiconductor devices from electrostatic discharge stress owing to their simple construction,easy triggering,and low power dissipation.We present a novel I-V characterization of the GGNMOS used as the power clamp in complementary metal-oxide-semiconductor circuits as a result of switching the ESD paths under different impact energies.This special effect could cause an unexpected latch-up or pre-failure phenomenon in some applications with relatively large capacitances from power supply to power ground,and thus should be urgently analyzed and resolved.Transmission-linepulse,human-body-modal,and light-emission tests were performed to explore the root cause.
基金the Sichuan Science and Technology Program(Nos.23ZHCG0049,2023YFG0078,23ZHCG0030,2021ZDZX0007)SCU-SUINING Project(2022CDSN-14).
文摘To solve the problem of long response time when users obtain suitable cutting parameters through the Internet based platform,a case-based reasoning framework is proposed.Specifically,a Hamming distance and Euclidean distance combined method is designed to measure the similarity of case features which have both numeric and category properties.In addition,AHP(Analytic Hierarchy Process)and entropy weight method are integrated to provide features weight,where both user preferences and comprehensive impact of the index have been concerned.Grey relation analysis is used to obtain the similarity of a new problem and alternative cases.Finally,a platform is also developed on Visual Studio 2015,and a case study is demonstrated to verify the practicality and efficiency of the proposed method.This method can obtain cutting parameters which is suitable without iterative calculation.Compared with the traditional PSO(Particle swarm optimization algorithm)and GA(Genetic algorithm),it can obtain faster response speed.This method can provide ideas for selecting processing parameters in industrial production.While guaranteeing the characteristic information is similar,this approach can select processing parameters which is the most appropriate for the production process and a lot of time can be saved.
基金the Beijing Municipal Scienceand Technology Project (No.KM202111417006)the Academic Research Projects of Beijing Union University (Nos.ZK10202305 and ZK80202004)the Beijing Municipal Science and Technology Project (No.KM202111417005)。
文摘Due to the diversity of work requirements and environment,the number of degrees of freedom(DOFs)and the complexity of structure of industrial robots are constantly increasing.It is difficult to establish the accurate dynamical model of industrial robots,which greatly hinders the realization of a stable,fast and accurate trajectory tracking control.Therefore,the general expression of the constraint relation in the explicit dynamic equation of the multi-DOF industrial robot is derived on the basis of solving the Jacobian matrix and Hessian matrix by using the kinematic influence coefficients method.Moreover,an explicit dynamic equation with general constraint relation expression is established based on the Udwadia-Kalaba theory.The problem of increasing the time of establishing constraint relationship when the multi-DOF industrial robots complete complex task constraints is solved.With the SCARA robot as the research object,the simulation results show that the proposed method can provide a new idea for industrial robot system modeling with complex constraints.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.41774085,41074132,41274193,41474166,41774195 and 41874187).
文摘Extreme space weather events including≥X5.0 flares,ground level enhancement(GLE)events and super geomagnetic storms(Dst≥-250 nT)caused by super active regions(SARs)during solar cycles 21-24 were studied.The total number ofX5.0 solar flares was 62,among which 41 were X5.0-X9.9 flares and 21 were≥X10.0 flares.We found that 83.9%of the≥X5.0 flares were produced by SARs;78.05%of the X5.0-X9.9 and 95.24%of the≥X10.0 solar flares were produced by SARs;46 GLEs were registered during solar cycles 21-24,and 25 GLEs were caused by SARs,indicating that 54.3%of the GLEs were caused by SARs;24 super geomagnetic storms were recorded during solar cycles 21-24,and 12 of them were caused by SARs,namely 50%of the super geomagnetic storms were caused by SARs.We ascertained that only 29 SARs produced≥X5.0 flares,15 SARs generated GLEs and 10 SARs triggered super geomagnetic storms.Of the 51 SARs,only 33 SARs produced at least one extreme space weather event,while none of the other 18 SARs could trigger an extreme space weather event.There were only four SARs and each of them generated not only a≥X5.0 flare,but also a GLE event and a super geomagnetic storm.Most of the extreme space weather events caused by the SARs appeared during solar cycles 22 and 23,especially for GLE events and super geomagnetic storms.The longitudinal distributions of source locations for the extreme space weather events caused by SARs were also studied.
文摘A new low power, low phase jitter, compact realization, and sell-biased PLL, which is fabricated on SMIC 40 nm CMOS technology is introduced. The proposed self-biased PLL eliminates extra band gap biasing circuits, and internally generates all the biasing voltages and currents. Meanwhile, all of the PLL dynamic loop parameters, such as loop bandwidth, natural frequency, damping factors are kept constant adaptively. By optimizing the circuit structures, the perfect unity of chip estate, power dissipation, phase jitter, and loop stability is achieved. THe PLL consumes 4.2 mW of power tinder 1.1 V/2.5 V voltage supply at 2.4 GHz VCO frequency, while occupying a die area of less than 0.02 mmz （180 × 110 μm2）, and the typical period jitter （RMS） is around 2.8 ps.
基金Supported by Innovation Team and Talents Cultivation Program of National Administration of Traditional Chinese Medicine(No.ZYYCXTD-C-202006)Longitudinal Development Funding of Beijing University of Chinese Medicine(No.2021-ZXFZJJ-016)+1 种基金the National Institute for Health Research(No.SPCR-143)Shanxi Provincial Health Commission Project(No.2020050)。
文摘Background:Primary dysmenorrhea(PD)is the most common complaint associated with menstruation and affects up to three-quarters of women at some stage of their reproductive life.In Chinese medicine,navel therapy,treatment provided at Shenque(CV 8),is used as a treatment option for PD.Objective:To evaluate the effect of navel therapy on pain relief and quality of life in women with PD,compared with Western medicine(WM).Methods:China National Knowledge Infrastructure(CNKI),Chinese Scientific Journal Database(VIP),Sino Med and Wanfang Database,MEDLINE,the Cochrane Library,Embase,Web of Science,and the International Clinical Trial Registry of the U.S.National Institutes of Health were searched from their inceptions to April 1,2021.Randomized controlled trials(RCTs)assessing therapeutic effects of navel therapy on PD were eligible for inclusion.Rev Man 5.4 software was used for data analyses.The certainty of the evidence was assessed using the online GRADEpro tool.Results:Totally 24 RCTs involving 2,614 participants were identified.Interventions applied to acupuncture point CV 8 included:herbal patching,moxibustion or combined navel therapy(using at least 2 types of stimulation).Compared to placebo,there was a significant effect in favor of navel therapy on reducing overall menstrual symptom scores at the end of treatment[mean difference:-0.82,95%confidence interval(CI):-1.00 to-0.64,n=90;1 RCT].As compared with Western medicine,navel therapy had a superior effect on pain intensity as assessed by Visual Analogue Scale at the end of treatment[standardized mean difference(SMD):-0.64,95%CI:-1.22 to-0.06,I^(2)=80%,n=262;3 RCTs];on symptom resolution rate at 3-month follow-up(risk ratio:1.94,95%CI:1.47 to 2.56,n=1527,I^(2)=38%;13 RCTs);and on global menstrual symptoms score at the end of treatment(SMD:-0.67,95%CI:-0.90 to-0.45,I^(2)=63%,n=990;12 RCTs).Subgroup analyses showed either a better or an equivalent effect comparing navel therapy with Western medicine.No major adverse events were reported.The methodological quality of included trials was poor overall.Conclusions:Navel therapy appears to be more effective than Western medicine in decreasing menstrual pain and improving overall symptoms of PD.However,these findings need to be confirmed by well-designed clinical trials with adequate sample size(Systematic review registration at PROSPERO,No.CRD42021240350).
基金Joint Funds of National Natural Science Foundation of China,Grant/Award Number:U2141202National Natural Science Foundation of China,Grant/Award Numbers:12102194,21905084,22105103Natural Science Foundation of Jiangsu Province,Grant/Award Number:BK20200471。
文摘It is still a huge challenge to introduce effective crack-healing ability into energetic composites with a high oxidizer content.In this article,a poly(urea-urethane)energetic elastomer was prepared by the polycondensation reaction of glycidyl azido polymer(GAP),isophorone diisocyanate(IPDI),and 2-aminophenyl disulfide(2-APD).In the poly(urea-urethane)elastomer structure,the hybrid dynamic lock,including multilevel H-bonds and disulfide bonds,not only provides abundant dynamic interactions and promotes chain diffusion,but also enhances physical crosslinking density.Such a unique design fabricated the energetic elastomer with robust tensile strength(0.72MPa),high stretchability(1631%),and outstanding toughness(8.95MJ/m 3)in the field of energetic polymers.Meanwhile,this energetic elastomer exhibited high self-healing efficiency(98.4%at 60°C)and heat release(Q=1750.46J/g).Experimental and theoretical results adequately explain the self-healing mechanism,particularly the role of azido units.The high-solid content(80wt%)energetic composites based on the energetic elastomer presented outstanding micro-defect self-healing(97.8%)and recycling without loss of mechanical performance.The development of smart energetic composites with excellent self-healing and recyclable ability provides a meaningful way for a wide range of applications in the field of energetic materials.
