To keep even current distribution among DC/DC converters in a paralleled power system,an automatic master-slave control （AMSC） current sharing scheme is presented,which was implemented by a current share control IC....To keep even current distribution among DC/DC converters in a paralleled power system,an automatic master-slave control （AMSC） current sharing scheme is presented,which was implemented by a current share control IC. A current feedback loop for output voltage adjustment is proposed for low signal distortion. Moreover,a special startup control logic is designed to improve startup timing and to speed up the initial current sharing. It was completed in 1.5μm bipolar-CMOS-DMOS （BCD） technology with an area of 3.6mm^2 . Using it,a paralleled power system of two DC/DC converters capable of outputting 12V/3A was built. Experimental results show that the current sharing error at full load is kept within 1%.展开更多
The electronic structure of five conformers of 2-chloroethanol was studied by ab initio calculations at B3LYP and MP2 levels of theory with aug-cc-pVTZ basis set. The existing hydrogen bond and hyperconjugation effect...The electronic structure of five conformers of 2-chloroethanol was studied by ab initio calculations at B3LYP and MP2 levels of theory with aug-cc-pVTZ basis set. The existing hydrogen bond and hyperconjugation effects on the stability of 2-chloroethanol conformers were discussed on the base of natural bond orbital analyses. The result exhibits that hyperconjugation is the main factor to determine the stability of conformers. Such effects on the electron wavefunctions of the highest-occupied molecular orbital （HOMO） of different conformers are demonstrated with electron momentum spectroscopy, exhibiting the obviously different symmetries of the HOMO wavefunctions in momentum space.展开更多
Objective:This study aims to evaluate the effects of a symptom management intervention(SMI)based on symptom management group sessions combined with a mobile health(mHealth)application(app)on the knowledge of symptom m...Objective:This study aims to evaluate the effects of a symptom management intervention(SMI)based on symptom management group sessions combined with a mobile health(mHealth)application(app)on the knowledge of symptom management,the certainty of symptom self-management,symptom severity,symptom distress,medication adherence,social support,and quality of life among persons living with HIV(PLWH)in China.Methods:A parallel randomized controlled trial with 61 PLWH was conducted in Shanghai,China.The participants in the control group(n¼30)downloaded the Symptom Management(SM)app according to their needs and preferences,and received routine follow-ups.The participants in the intervention group(n¼31)were guided to download and use the SM app,and received four tailored weekly group sessions at routine follow-ups.Each group session lasted for approximately 2 h and targeted one of the major modules of the SM app.All the outcomes were assessed at baseline and post-intervention.The study was registered with the Chinese Clinical Trial Registry(ChiCTR1900024821).Results:The symptom management knowledge and certainty of symptom self-management were significantly improved after the intervention(all P<0.01).Compared with the control group,the scores of symptoms reasons knowledge score improved 11.47 points(95%CI:3.41,19.53)and scores of symptoms self-management knowledge score improved 12.80 points(95%CI:4.55,21.05)in the intervention group after controlling for covariates.However,other outcomes did not show statistically significant differences between the intervention group and the control group(P>0.05).Conclusion:The SMI could improve PLWH’s symptom management knowledge and certainty of symptom self-management.Multi-center studies with larger sample sizes and longer follow-ups are needed to further understand the effects of SM app on ameliorating symptom severity and symptom distress.More innovative strategies are also needed to promote and maintain the sustainability of the SM app.展开更多
Ion selectivity in protein binding sites is of great significance to biological functions.Although additive force fields have been successfully applied to various protein-related studies,it is difficult to well captur...Ion selectivity in protein binding sites is of great significance to biological functions.Although additive force fields have been successfully applied to various protein-related studies,it is difficult to well capture the subtle metal-protein interaction for the prediction of ion selectivity,due to the remarkable polarization and charge transfer effect between the metals and the surrounding residues.Quantum mechanics-based methods are well-suited for dealing with these systems,but they are too costly to apply in a direct manner.In this work,the reference-potential method(RPM)was used to measure the selectivity for calcium and magnesium cations in the binding pocket of parvalbumin B protein by calculating the free energy change associated with this substitution reaction at an ab initio quantum mechanics/molecular mechanics(QM/MM)level.The alchemical transformations were performed at the molecular mechanics level,and the relative binding free energy was then corrected to the QM/MM level via thermodynamic perturbation.In this way,the free energy change at the QM/MM level for the substitution reaction was obtained without running the QM/MM simulations,thus remarkably enhancing the efficiency.In the reweighting process,we found that the selection of the QM region greatly affects the accuracy of the QM/MM method.In particular,the charge transfer effect on the free energy change of a reaction cannot be neglected.展开更多
Butterworth band-pass filter has been applied to S-wave data recorded at 8 stations in China mainland, and S-wave splitting at different frequency bands is analyzed. The results show that the delay time and the fast p...Butterworth band-pass filter has been applied to S-wave data recorded at 8 stations in China mainland, and S-wave splitting at different frequency bands is analyzed. The results show that the delay time and the fast polarization directions of S-wave splitting depend upon the frequency bands. There is an absence of S-wave splitting at the station of Urumqi (WMQ) for the band of 0.1-0.2 Hz. With the frequency band broadening, the delay time of S-wave splitting decreases at the stations of Beijing (BJI), Enshi (ENH), Kunming (KMI) and Mudanjiang (MDJ); the fast polarization direction changes from westward to eastward at Enshi (ENH), and from eastward to westward at Hailaer (HIA). The variations of delay time with bands at Lanzhou (LZH) and Qiongzhong (QIZ) are similar, and there is a coherent trend of fast polarization directions at BJI, KMI and MDJ, respectively. Initial interpretations to the results of frequency band-dependence of S-wave splitting are also presented.展开更多
文摘To keep even current distribution among DC/DC converters in a paralleled power system,an automatic master-slave control （AMSC） current sharing scheme is presented,which was implemented by a current share control IC. A current feedback loop for output voltage adjustment is proposed for low signal distortion. Moreover,a special startup control logic is designed to improve startup timing and to speed up the initial current sharing. It was completed in 1.5μm bipolar-CMOS-DMOS （BCD） technology with an area of 3.6mm^2 . Using it,a paralleled power system of two DC/DC converters capable of outputting 12V/3A was built. Experimental results show that the current sharing error at full load is kept within 1%.
文摘The electronic structure of five conformers of 2-chloroethanol was studied by ab initio calculations at B3LYP and MP2 levels of theory with aug-cc-pVTZ basis set. The existing hydrogen bond and hyperconjugation effects on the stability of 2-chloroethanol conformers were discussed on the base of natural bond orbital analyses. The result exhibits that hyperconjugation is the main factor to determine the stability of conformers. Such effects on the electron wavefunctions of the highest-occupied molecular orbital （HOMO） of different conformers are demonstrated with electron momentum spectroscopy, exhibiting the obviously different symmetries of the HOMO wavefunctions in momentum space.
基金This paper is part of a project funded by the National Natural Science Foundation of China(Grant Number 71673057)the China Scholarship Council(No.201906100135).
文摘Objective:This study aims to evaluate the effects of a symptom management intervention(SMI)based on symptom management group sessions combined with a mobile health(mHealth)application(app)on the knowledge of symptom management,the certainty of symptom self-management,symptom severity,symptom distress,medication adherence,social support,and quality of life among persons living with HIV(PLWH)in China.Methods:A parallel randomized controlled trial with 61 PLWH was conducted in Shanghai,China.The participants in the control group(n¼30)downloaded the Symptom Management(SM)app according to their needs and preferences,and received routine follow-ups.The participants in the intervention group(n¼31)were guided to download and use the SM app,and received four tailored weekly group sessions at routine follow-ups.Each group session lasted for approximately 2 h and targeted one of the major modules of the SM app.All the outcomes were assessed at baseline and post-intervention.The study was registered with the Chinese Clinical Trial Registry(ChiCTR1900024821).Results:The symptom management knowledge and certainty of symptom self-management were significantly improved after the intervention(all P<0.01).Compared with the control group,the scores of symptoms reasons knowledge score improved 11.47 points(95%CI:3.41,19.53)and scores of symptoms self-management knowledge score improved 12.80 points(95%CI:4.55,21.05)in the intervention group after controlling for covariates.However,other outcomes did not show statistically significant differences between the intervention group and the control group(P>0.05).Conclusion:The SMI could improve PLWH’s symptom management knowledge and certainty of symptom self-management.Multi-center studies with larger sample sizes and longer follow-ups are needed to further understand the effects of SM app on ameliorating symptom severity and symptom distress.More innovative strategies are also needed to promote and maintain the sustainability of the SM app.
基金supported by the Ministry of Science and Technology of China(No.2016YFA0501700)the National Natural Science Foundation of China(No.22073030)supported by the Supercomputer Center of East China Normal University(ECNU Public Platform for Innovation No.001)。
文摘Ion selectivity in protein binding sites is of great significance to biological functions.Although additive force fields have been successfully applied to various protein-related studies,it is difficult to well capture the subtle metal-protein interaction for the prediction of ion selectivity,due to the remarkable polarization and charge transfer effect between the metals and the surrounding residues.Quantum mechanics-based methods are well-suited for dealing with these systems,but they are too costly to apply in a direct manner.In this work,the reference-potential method(RPM)was used to measure the selectivity for calcium and magnesium cations in the binding pocket of parvalbumin B protein by calculating the free energy change associated with this substitution reaction at an ab initio quantum mechanics/molecular mechanics(QM/MM)level.The alchemical transformations were performed at the molecular mechanics level,and the relative binding free energy was then corrected to the QM/MM level via thermodynamic perturbation.In this way,the free energy change at the QM/MM level for the substitution reaction was obtained without running the QM/MM simulations,thus remarkably enhancing the efficiency.In the reweighting process,we found that the selection of the QM region greatly affects the accuracy of the QM/MM method.In particular,the charge transfer effect on the free energy change of a reaction cannot be neglected.
基金the National Natural Science Foundation of China (NSFC) (Grant No. 49774225), and the Outstanding Youth Scientist Project from NSFC (Grant No. 49825108).
文摘Butterworth band-pass filter has been applied to S-wave data recorded at 8 stations in China mainland, and S-wave splitting at different frequency bands is analyzed. The results show that the delay time and the fast polarization directions of S-wave splitting depend upon the frequency bands. There is an absence of S-wave splitting at the station of Urumqi (WMQ) for the band of 0.1-0.2 Hz. With the frequency band broadening, the delay time of S-wave splitting decreases at the stations of Beijing (BJI), Enshi (ENH), Kunming (KMI) and Mudanjiang (MDJ); the fast polarization direction changes from westward to eastward at Enshi (ENH), and from eastward to westward at Hailaer (HIA). The variations of delay time with bands at Lanzhou (LZH) and Qiongzhong (QIZ) are similar, and there is a coherent trend of fast polarization directions at BJI, KMI and MDJ, respectively. Initial interpretations to the results of frequency band-dependence of S-wave splitting are also presented.
