A deep understanding of explosive sensitivities and their factors is important for safe and reliable applications.However,quantitative prediction of the sensitivities is difficult.Here,reactive molecular dynamics simu...A deep understanding of explosive sensitivities and their factors is important for safe and reliable applications.However,quantitative prediction of the sensitivities is difficult.Here,reactive molecular dynamics simulation models for high-speed piston impacts on explosive supercells were established.Simulations were also performed to investigate shock-induced reactions of various high-energy explosives.The fraction of reacted explosive molecules in an initial supercell changed linearly with the propagation distance of the shock-wave front.The corresponding slope could be used as a reaction rate for a specific shock-loading velocity.Reaction rates that varied with the shock-loading pressure exhibited two-stage linearities with different slopes.The two inflection points corresponded to the initial and accelerated reactions,which respectively correlated to the thresholds of shock-induced ignition and detonation.Therefore,the ignition and detonation critical pressures could be determined.The sensitivity could then be a quantitative prediction of the critical pressure.The accuracies of the quantitative shock sensitivity predictions were verified by comparing the impact and shock sensitivities of common explosives and the characteristics of anisotropic shock-induced reactions.Molecular dynamics simulations quantitatively predict and rank shock sensitivities by using only crystal structures of the explosives.Overall,this method will enable the design and safe use of explosives.展开更多
The reactive power optimization considering voltage stability is an effective method to improve voltage stablity margin and decrease network losses,but it is a complex combinatorial optimization problem involving nonl...The reactive power optimization considering voltage stability is an effective method to improve voltage stablity margin and decrease network losses,but it is a complex combinatorial optimization problem involving nonlinear functions having multiple local minima and nonlinear and discontinuous constraints. To deal with the problem,quantum particle swarm optimization (QPSO) is firstly introduced in this paper,and according to QPSO,chaotic quantum particle swarm optimization (CQPSO) is presented,which makes use of the randomness,regularity and ergodicity of chaotic variables to improve the quantum particle swarm optimization algorithm. When the swarm is trapped in local minima,a smaller searching space chaos optimization is used to guide the swarm jumping out the local minima. So it can avoid the premature phenomenon and to trap in a local minima of QPSO. The feasibility and efficiency of the proposed algorithm are verified by the results of calculation and simulation for IEEE 14-buses and IEEE 30-buses systems.展开更多
Due to the development of Distributed Generation (DG), which is installed in Medium-Voltage Distribution Networks (MVDNs) such as generators based on renewable energy (e.g., wind energy or solar energy), voltage contr...Due to the development of Distributed Generation (DG), which is installed in Medium-Voltage Distribution Networks (MVDNs) such as generators based on renewable energy (e.g., wind energy or solar energy), voltage control is currently a very important issue. The voltage is now regulated at the MV busbars acting on the On-Load Tap Changer of the HV/MV transformer. This method does not guarantee the correct voltage value in the network nodes when the distributed generators deliver their power. In this paper an approach based on Sensitivity Theory is shown, in order to control the node voltages regulating the reactive power exchanged between the network and the dispersed generators. The automatic distributed voltage regulation is a particular topic of the Smart Grids.展开更多
An approximate analytical model for calculating the pull-in voltage of a stepped cantilever-type radio frequency （RF） micro electro-mechanical system （MEMS） switch is developed based on the Euler-Bernoulli beam an...An approximate analytical model for calculating the pull-in voltage of a stepped cantilever-type radio frequency （RF） micro electro-mechanical system （MEMS） switch is developed based on the Euler-Bernoulli beam and a modified couple stress theory, and is validated by comparison with the finite element results. The sensitivity functions of the pull-in voltage to the designed parameters are derived based on the proposed model. The sensitivity investigation shows that the pull-in voltage sensitivities increase/decrease nonlinearly with the increases in the designed parameters. For the stepped cantilever beam, there exists a nonzero optimal dimensionless length ratio, where the pull-in voltage is insensitive. The optimal value of the dimensionless length ratio only depends on the dimensionless width ratio, and can be obtained by solving a nonlinear equation. The determination of the designed parameters is discussed, and some recommendations are made for the RF MEMS switch optimization.展开更多
Energy storage is an effective measure to deal with internal power fluctuation of micro-grid and ensure stable operation, especially in the micro-grid with high photovoltaic(PV) penetration. Its capacity configuration...Energy storage is an effective measure to deal with internal power fluctuation of micro-grid and ensure stable operation, especially in the micro-grid with high photovoltaic(PV) penetration. Its capacity configuration is related to the steady, safety and economy of micro-grid.In order to improve the absorptive capacity of micro-grid on maximizing the use of distributed PV power in micro-grid, and improve the power quality, an optimal energy storage configuration strategy is proposed, which takes many factors into account, such as the topology of micro-grid, the change of irradiance, the load fluctuation and the cable. The strategy can optimize the energy storage allocation model to minimize the storage power capacity and optimize the node configuration.The key electrical nodes are identified by using the sensitivity coefficient of the voltage, and then the model is optimized to simplify calculation. Finally, an example of the European low-voltage micro-grid and a micro-grid system in the laboratory is used to verify the effectiveness of the proposed method.The results show that the proposed method can optimize the allocation of capacity and the node of the energy storage system.展开更多
Background: Research has shown that high-sensitivity C-reactive protein (hs-CRP) is a major inflammatory marker for prediction of acute coronary syndrome (ACS). Myeloperoxidase (MPO) also plays an important role in at...Background: Research has shown that high-sensitivity C-reactive protein (hs-CRP) is a major inflammatory marker for prediction of acute coronary syndrome (ACS). Myeloperoxidase (MPO) also plays an important role in atherosclerosis initiation and development. In present study, the major adverse cardiovascular events (MACEs) of patients with coronary heart disease (CHD) were investigated. Methods: MPO, hs-CRP and ACS-related risk factors from 201 ACS (78 AMI and 123 UAP) and 210 non-ACS (84 SAP and 126 non-CHD) patients confirmed by coronary angiography were detected, and the data were analyzed with receiver operating characteristic (ROC) curve and Spearman’s correlation coefficients. MACEs of 285 CHD patients were investigated during the 4-year period follow-up from March 2010 to May 2014. Results: The areas under ROC curve for diagnosing ACS were 0.888 (95% CI 0.843 - 0.933) for MPO, and 0.862 (95% CI 0.815-0.910) for hs-CRP, respectively. There were significantly correlations between MPO and hs-CRP in both ACS and non-ACS groups. Regarding to ACS patients, both MPO and hs-CRP were positively correlated with BMI, TC, TG, LDL-C and Hcy. Prospective study demonstrated that the incidences of MACEs associated significantly with elevated MPO baseline level (yes vs no, OR 7.383, 95% CI 4.095 - 13.309) and high hs-CRP baseline level (yes vs no, OR 4.186, 95% CI 2.469 - 7.097) in CHD patients. Conclusions: The present study provides the epidemiological evidence that elevated baseline MPO and hs-CRP levels are both valuable predictors of MACEs in CHD patients. MPO and hs-CRP would prompt the progression of atherosclerosis and development from SAP to ACS.展开更多
BACKGROUND： Cerebral infarction is poorly treated due to neuronal necrosis and secondary pathophysiological changes; for example, free radical production and inflammatory reactions. OBJECTIVE： To detect the levels o...BACKGROUND： Cerebral infarction is poorly treated due to neuronal necrosis and secondary pathophysiological changes; for example, free radical production and inflammatory reactions. OBJECTIVE： To detect the levels of high-sensitivity C-reactive protein （hs-CRP）, interleukin-6 （IL-6）, and tumor necrosis factor- a （TNF- α ） in elderly males with cerebral infarction. DESIGN： Non-randomized current control study. SETTING： Cadre Medical Department, Guizhou Provincial People＇s Hospital. PARTICIPANTS： Forty elderly males （65-89 years old） with cerebral infarction were selected from Cadre Medical Department, Guizhou Provincial People＇s Hospital from February 2004 to December 2006. All patients met the diagnostic criteria of cerebral infarction modified at the 4th National Cerebrovascular Disease Academic Meeting, and were diagnosed on the basis of CT or MRI tests. Furthermore, 35 elderly male inpatients （65-87 years old） without cerebral infarction were selected as the control group. Included subjects provided confirmed consent and did not have heart disease, diabetes mellitus, lipid disorder, acute trauma, infection, rheumatism, or other inflammatory diseases. The study was approved by the local ethics committee. There were no significant differences in age, blood pressure, and lipid levels between the cerebral infarction group and the control group （P 〉 0.05）, and this suggested that the baseline data of both groups were comparable. METHODS： Fasting venous blood was drawn from cerebral infarction patients 24 hours after cerebral infarction attack and from control subjects 24 hours after hospitalization. A latex-enhanced immunoturbidimetric assay and an enzyme-linked immunosorbent assay were used to detect the levels of hs-CRP, IL-6, and TNF- α in the serum. MAIN OUTCOME MEASURES： The levels of hs-CRP, 1L-6, and TNF- α in the serum in both groups. RESULTS： Forty cerebral infarction patients and thirty-five control subjects were included in the final analysis without any loss. Levels of hs-CRP, IL-6, and TNF-α in the cerebral infarction group were significantly higher than those in the control group （P 〈 0.01 ）. CONCLUSION： Levels of serum inflammatory reactive factors are increased in elderly males with cerebral infarction.展开更多
Voltage dip is one of the detrimental power quality problems that can lead to huge financial losses in industries. Its economic impact is not only associated with the quality of the supply but also with sensitivity of...Voltage dip is one of the detrimental power quality problems that can lead to huge financial losses in industries. Its economic impact is not only associated with the quality of the supply but also with sensitivity of electronic controls and equipment of the industry which are susceptible to voltage dips. Mitigating solutions are available but the choice depends on the careful assessment of the economic impact of voltage dips and economic gains of solutions. This paper presents an approach for estimating the economic cost of voltage dips based on sensitivity analysis. The voltage-tolerance curves of the sensitive equipment are obtained from experimental tests under different conditions. From the behavior and interaction of process equipment, different failure modes and economic sensitivity density are determined for different types of voltage dips. Voltage events monitored in the MV-network for several years are assessed to determine the frequency and severity of voltage dips at the customer terminal. The economic values of equipment and processes are assessed to get insight into alternative solutions with more rewarding measures. Then, cost-benefit analysis is performed to compare the economic gains of solutions protecting equipment or processes showing more rewarding economic values.展开更多
Objective To describe the distribution of plasma high sensitivity C-reactive protein （hsCRP） and explore the relationship between hsCRP and metabolic risk factors among residents living in longevity areas of China. ...Objective To describe the distribution of plasma high sensitivity C-reactive protein （hsCRP） and explore the relationship between hsCRP and metabolic risk factors among residents living in longevity areas of China. Methods 268 individuals aged between 40 and 59 years and 506 individuals aged over 90 years were selected from 5 longevity areas of China to participate in a cross section longitudinal cohort study. The participants were interviewed with general health related questionnaire to collect their demographic, behavioral and lifestyle data, as well as their chronic conditions, and meanwhile their physical and biomedical parameters including waist circumference （WC）, blood pressure （BP）, hsCRP, plasma lipids, and fasting blood glucose （FBG） were measured. Results The median of hsCRP was 0.99 mg/L in the middle-aged group and 2.76 mg/L in the oldest old group. No significant gender difference was observed between the above two groups. Among the oldest old individuals, 36.56% had an hsCRP level 〉3.0 mg/L. The prevalence of high hsCRP was 26.79% in the middle-aged group. The results of stepwise multiple linear regression analyses showed that HDL-C was independently associated with In （hsCRP） concentration in the middle-aged group, whereas In （TG）, HDL-C and FBG were correlated after adjustment for gender, study site, smoking, drinking, education and BMI in the oldest old group. Conclusion HDL-C is a stronger predictor of elevated hsCRP than other metabolic factors in the middle-aged population. For the oldest old persons, high TG, low HDL-C, and FBG predict elevated plasma hsCRP.展开更多
Biomarkers are early predictors of various disorders, circulating level of C-reactive protein is a sensitive biomarker of systemic inflammation and may also be associated with the development of diabetic, hepatic, and...Biomarkers are early predictors of various disorders, circulating level of C-reactive protein is a sensitive biomarker of systemic inflammation and may also be associated with the development of diabetic, hepatic, and cardiovascular diseases. In the present study, we aimed to investigate the association between circulating levels of high sensitive C-reactive protein (hs-CRP) and various biomarkers for hepatic, diabetic, and cardiovascular health. The retrospective analysis included 438 individuals who were tested for these panels simultaneously at Vibrant America Clinical Laboratory. The study population included free-living individuals without any preexisting clinical conditions. Among the cardiovascular markers, a positive correlation and significant association was found between high levels of hs-CRP and serum levels of triglycerides (r = 0.0964, p −0.1423, p −0.1216, p < 0.0105) with circulating levels of hs-CRP. Among all the diabetic markers, glucose (r = 0.1547, p < 0.0011) and glycated serum protein (r = 0.1725, p < 0.0003) were positively correlated with circulating hs-CRP. In the hepatic panel, AST, a transaminase that plays a vital role in amino acid metabolism, was found to have a strong positive correlation with hs-CRP (r = 0.2139, p < 0.0001). In conclusion, the results clearly show the association of hs-CRP with diabetic, hepatic, and cardiovascular risk factors indicating its central value as a key marker for several lifestyle-associated disorders.展开更多
This study was undertaken to investigate the correlation of the enhancement degree on contrast-enhanced ultrasound(CEUS) with the histopathology of carotid plaques and the serum high sensitive C-reactive protein(hs-CR...This study was undertaken to investigate the correlation of the enhancement degree on contrast-enhanced ultrasound(CEUS) with the histopathology of carotid plaques and the serum high sensitive C-reactive protein(hs-CRP) levels in patients undergoing carotid endarterectomy(CEA). Carotid CEUS was performed preoperatively in 115 patients who would undergo CEA, and the enhancement degree of the carotid plaques was evaluated by both the visual semiquantitative analysis and the quantitative time-intensity curve analysis. Serum hs-CRP levels were detected using the particle-enhanced immunoturbidimetric assay also before the operation. Additionally, the carotid plaque samples were subjected to histopathological examination postoperatively. The density of neovessels and the number of macrophages in the plaques were assessed by immunohistochemistry. The results showed that among the 115 patients, grade 0 plaque contrast enhancement was noted in 35 patients, grade 1 in 48 patients and grade 2 in 32 patients. The degree of plaque enhancement, the density of neovessels, the number of macrophages, and the hs-CRP levels were highest in the grade 2 patients. Correlation analysis showed that the enhancement degree of the carotid plaques was closely related to the immunohistochemical parameters of the plaques and the serum hs-CRP levels. It was suggested that the carotid plaque enhancement on CEUS can be used to evaluate the vulnerability of carotid plaques.展开更多
A process of preparing ZnO voltage sensitive ceramics doped with some oxides by coprecipitation was described in the paper. The thermal properties of ZnO nanometer powders and the current voltage characteristics of ...A process of preparing ZnO voltage sensitive ceramics doped with some oxides by coprecipitation was described in the paper. The thermal properties of ZnO nanometer powders and the current voltage characteristics of the ceramics have been investigated. The results showed that the six additive ZnO powders with hexagonal system were homogeneous grain size distribution in microstructure, the optimal reaction pH is 6.90±0.05, the temperature for calcining and sintering was at about 500 ℃ and 1100 ℃, respectively. The powders were also examined by SEM, IR and XRD etc, and the effect of doping La 2O 3 on the electrical properties of ZnO varistor was investigated too.展开更多
Global warming poses a severe threat to rice production and food security.We identified a heat-sensitive mutant hs1 through largescale screening of an established rice mutant library,and subsequently cloned the corres...Global warming poses a severe threat to rice production and food security.We identified a heat-sensitive mutant hs1 through largescale screening of an established rice mutant library,and subsequently cloned the corresponding gene HS1,which confers thermotolerance in rice.HS1 is localized to the chloroplast and functions by preserving chloroplast integrity under elevated temperatures through stabilizing the photosystem I subunit protein PsaC.Loss of HS1 function in the hs1 mutant leads to severe structural damage to the chloroplast under heat stress,accompanied by intracellular accumulation of reactive oxygen species(ROS),which in turn triggers DNA damage and leaf albinism,ultimately manifesting as a heat-sensitive phenotype.展开更多
Objective:To explore the application value of neutrophil/lymphocyte ratio (NLR) combined with high sensitive C reactive protein (hs-CRP) in the evaluation of community acquired pneumonia (CAP). Methods:From November 2...Objective:To explore the application value of neutrophil/lymphocyte ratio (NLR) combined with high sensitive C reactive protein (hs-CRP) in the evaluation of community acquired pneumonia (CAP). Methods:From November 2015 to October 2016, 58 cases of CAP patients admitted in our department were selected as research objects and were divided into low risk group and high risk group according to the PSI score and CURB-65 standard for evaluation. They were divided into improved group (48 cases) and death group (10 cases) according to prognosis. Hs-CRP was determined by immunoturbidimetric assay, procalcitonin (PCT) by immunofluorescence, NLR by count method of laser scattering, and white blood (WBC) was counted. The differences in WBC, PCT, NLR and hs-CRP between different risk groups were compared, and the correlation was evaluated using Spearman's rank correlation analysis method. The changes in indexes were observed in the improved and death cases. Results:The high risk group had higher NLR, PCT and hs-CRP than low risk group (P<0.05), while no significant difference was found in WBC (P>0.05). No correlation was found between NLR and WBC, while a strong correlation was found between hs-CRP and PCT. The WBC, PCT, NLR and hs-CRP levels were significantly lower in the improved group than the death group (P<0.05). Conclusions:NLR combined with hs-CRP, WBC, and PCT has a good assessment of the severity of CAR, and high levels of NLR, hs-CRP, WBC, and PCT predict the severity of the disease and poor prognosis.展开更多
Temperature inferential control (TIC) is studied for a reactive distillation column with double reactive sections (RDC-DRSs) processing a hypothetical two-stage consecutive reversible reaction (A + B■C + D, C + B■E ...Temperature inferential control (TIC) is studied for a reactive distillation column with double reactive sections (RDC-DRSs) processing a hypothetical two-stage consecutive reversible reaction (A + B■C + D, C + B■E + D with αD > αB > αC > αA > αE). Because of the complicated dynamic behaviors, the controlled stages by sensitivity analysis lead to great steady-state deviations (SSDs) in top and bottom product purities. Since TIC involves considerably reduced settling times in comparison with direct composition control, small SSDs in product qualities correspond generally to small transient deviations (TDs) in product qualities. An objective function that measures SSDs in product qualities is formulated to represent the performance of a TIC system and an iterative procedure is devised to search for the best control configuration. The application of the procedure to the RDC-DRS gives considerably suppressed TDs and SSDs in top and bottom product qualities as compared with the one by sensitivity analysis. The method is simpler in principle and less computationally intensive than the current practice. These striking outcomes show the effectiveness of the proposed principle for the development of TIC systems for complicated reactive distillation columns.展开更多
We developed a special methylene blue solution for staining of cervix shedding cells based on catalytic oxidizing chromogenic reaction, which shows a potential for cervical cancer cytology screening. We screened a tot...We developed a special methylene blue solution for staining of cervix shedding cells based on catalytic oxidizing chromogenic reaction, which shows a potential for cervical cancer cytology screening. We screened a total of 1 922 women for cervical cancer with the special methylene blue staining method and a conventional Pap smear method using cervix shedding cells. Then, the patients with positive indicators of the Pap smear or this special solution staining method were examined by the electron colposcopy and histopathological examination. Staining of cervical exfoliated cells with this reactive oxygen-based special solution showed that the number of positive cases was 140(7.28%). Among them, 21 cases showed dark green(1.09%), and 119 cases showed purple black(6.19%). The results of the Pap smear method showed that the number of positive cases was 123(6.40%), of which ASCUS was 105(5.46%), ASC-H was 5(0.26%), and LSIL was 9(0.47%), and HSIL was 4(0.21%). For cervical exfoliated cell special staining solution for screening cervical intraepithelial neoplasia(CIN-Ⅱ, CIN-Ⅲ) and cervical cancer, sensitivity was 83.33%, specificity was 65.52%, accuracy was 74.29%, missed diagnosis rate was 13.33%, positive coincidence rate was 51.43%, and the negative coincidence rate is 86.67%. Our results proved the value of this method for early screening of cervical cancer through clinical practice in China.展开更多
Half-wavelength transmission can transmit large-scale renewable energy over very long distances.This paper proposes an improved steady-state voltage-control method for half-wavelength transmission systems considering ...Half-wavelength transmission can transmit large-scale renewable energy over very long distances.This paper proposes an improved steady-state voltage-control method for half-wavelength transmission systems considering largescale wind-power transmission.First,the unique voltage characteristics of half-wavelength lines are deduced based on the distributed parameter model.In the secondary voltage-control level,reactive power-transmission limits of half-wavelength lines are introduced as another control objective except for tracing the pilot bus voltage reference.Considering the uncertainty and fluctuation of wind power,the overvoltage risk-assessment method of half-wavelength lines is presented to determine specific voltage-control strategies.Simulation results demonstrate that the proposed voltage-control method delivers superior tracking performance according to a voltage reference value and prevents the overvoltage risk of halfwavelength lines effectively in different wind-power penetrations.展开更多
Voltage sags in power system may lead to serious problems such as the off-grid of distributed generation and electrical equipment failures.As a novel type of power electronic equipment,a flexible multi-state switch(FM...Voltage sags in power system may lead to serious problems such as the off-grid of distributed generation and electrical equipment failures.As a novel type of power electronic equipment,a flexible multi-state switch(FMSS)is capable to support the voltage during the grid faults.In this paper,a voltage control strategy to support the voltage in a distribution network is proposed by introducing three-port FMSS.The positive-negative-sequence compensation(PNSC)scheme is adopted to control the active and reactive current.This control scheme eliminates active power oscillations at the port of voltage sags and reduces coupling oscillations of other ports.Based on the characteristics of the voltage support under PNSC scheme,two voltage support strategies are proposed.A proportional-integral controller is introduced to provide the reactive power references,which eliminates the errors when estimating the grid voltage and impedance.A current limiting scheme is adopted to keep the port current in a safe range by adjusting the active and reactive power references.The voltage support strategies in two different voltage sags are simulated,and results show the feasibility and effectiveness of the proposed control strategies.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11832006).
文摘A deep understanding of explosive sensitivities and their factors is important for safe and reliable applications.However,quantitative prediction of the sensitivities is difficult.Here,reactive molecular dynamics simulation models for high-speed piston impacts on explosive supercells were established.Simulations were also performed to investigate shock-induced reactions of various high-energy explosives.The fraction of reacted explosive molecules in an initial supercell changed linearly with the propagation distance of the shock-wave front.The corresponding slope could be used as a reaction rate for a specific shock-loading velocity.Reaction rates that varied with the shock-loading pressure exhibited two-stage linearities with different slopes.The two inflection points corresponded to the initial and accelerated reactions,which respectively correlated to the thresholds of shock-induced ignition and detonation.Therefore,the ignition and detonation critical pressures could be determined.The sensitivity could then be a quantitative prediction of the critical pressure.The accuracies of the quantitative shock sensitivity predictions were verified by comparing the impact and shock sensitivities of common explosives and the characteristics of anisotropic shock-induced reactions.Molecular dynamics simulations quantitatively predict and rank shock sensitivities by using only crystal structures of the explosives.Overall,this method will enable the design and safe use of explosives.
基金Sponsored by the Scientific and Technological Project of Heilongjiang Province(Grant No.GD07A304)
文摘The reactive power optimization considering voltage stability is an effective method to improve voltage stablity margin and decrease network losses,but it is a complex combinatorial optimization problem involving nonlinear functions having multiple local minima and nonlinear and discontinuous constraints. To deal with the problem,quantum particle swarm optimization (QPSO) is firstly introduced in this paper,and according to QPSO,chaotic quantum particle swarm optimization (CQPSO) is presented,which makes use of the randomness,regularity and ergodicity of chaotic variables to improve the quantum particle swarm optimization algorithm. When the swarm is trapped in local minima,a smaller searching space chaos optimization is used to guide the swarm jumping out the local minima. So it can avoid the premature phenomenon and to trap in a local minima of QPSO. The feasibility and efficiency of the proposed algorithm are verified by the results of calculation and simulation for IEEE 14-buses and IEEE 30-buses systems.
文摘Due to the development of Distributed Generation (DG), which is installed in Medium-Voltage Distribution Networks (MVDNs) such as generators based on renewable energy (e.g., wind energy or solar energy), voltage control is currently a very important issue. The voltage is now regulated at the MV busbars acting on the On-Load Tap Changer of the HV/MV transformer. This method does not guarantee the correct voltage value in the network nodes when the distributed generators deliver their power. In this paper an approach based on Sensitivity Theory is shown, in order to control the node voltages regulating the reactive power exchanged between the network and the dispersed generators. The automatic distributed voltage regulation is a particular topic of the Smart Grids.
基金supported by the National Natural Science Foundation of China(Nos.51505089 and61204116)the Opening Project of the Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory(Nos.ZHD201207 and 9140C030605140C03015)the Pearl River S&T Nova Program of Guangzhou(No.2014J2200086)
文摘An approximate analytical model for calculating the pull-in voltage of a stepped cantilever-type radio frequency （RF） micro electro-mechanical system （MEMS） switch is developed based on the Euler-Bernoulli beam and a modified couple stress theory, and is validated by comparison with the finite element results. The sensitivity functions of the pull-in voltage to the designed parameters are derived based on the proposed model. The sensitivity investigation shows that the pull-in voltage sensitivities increase/decrease nonlinearly with the increases in the designed parameters. For the stepped cantilever beam, there exists a nonzero optimal dimensionless length ratio, where the pull-in voltage is insensitive. The optimal value of the dimensionless length ratio only depends on the dimensionless width ratio, and can be obtained by solving a nonlinear equation. The determination of the designed parameters is discussed, and some recommendations are made for the RF MEMS switch optimization.
基金Supported by the National Program of International S&T Cooperation(No.2014DFE60020)Natural Science Foundation of Zhejiang Province(No.LY15E070004)
文摘Energy storage is an effective measure to deal with internal power fluctuation of micro-grid and ensure stable operation, especially in the micro-grid with high photovoltaic(PV) penetration. Its capacity configuration is related to the steady, safety and economy of micro-grid.In order to improve the absorptive capacity of micro-grid on maximizing the use of distributed PV power in micro-grid, and improve the power quality, an optimal energy storage configuration strategy is proposed, which takes many factors into account, such as the topology of micro-grid, the change of irradiance, the load fluctuation and the cable. The strategy can optimize the energy storage allocation model to minimize the storage power capacity and optimize the node configuration.The key electrical nodes are identified by using the sensitivity coefficient of the voltage, and then the model is optimized to simplify calculation. Finally, an example of the European low-voltage micro-grid and a micro-grid system in the laboratory is used to verify the effectiveness of the proposed method.The results show that the proposed method can optimize the allocation of capacity and the node of the energy storage system.
文摘Background: Research has shown that high-sensitivity C-reactive protein (hs-CRP) is a major inflammatory marker for prediction of acute coronary syndrome (ACS). Myeloperoxidase (MPO) also plays an important role in atherosclerosis initiation and development. In present study, the major adverse cardiovascular events (MACEs) of patients with coronary heart disease (CHD) were investigated. Methods: MPO, hs-CRP and ACS-related risk factors from 201 ACS (78 AMI and 123 UAP) and 210 non-ACS (84 SAP and 126 non-CHD) patients confirmed by coronary angiography were detected, and the data were analyzed with receiver operating characteristic (ROC) curve and Spearman’s correlation coefficients. MACEs of 285 CHD patients were investigated during the 4-year period follow-up from March 2010 to May 2014. Results: The areas under ROC curve for diagnosing ACS were 0.888 (95% CI 0.843 - 0.933) for MPO, and 0.862 (95% CI 0.815-0.910) for hs-CRP, respectively. There were significantly correlations between MPO and hs-CRP in both ACS and non-ACS groups. Regarding to ACS patients, both MPO and hs-CRP were positively correlated with BMI, TC, TG, LDL-C and Hcy. Prospective study demonstrated that the incidences of MACEs associated significantly with elevated MPO baseline level (yes vs no, OR 7.383, 95% CI 4.095 - 13.309) and high hs-CRP baseline level (yes vs no, OR 4.186, 95% CI 2.469 - 7.097) in CHD patients. Conclusions: The present study provides the epidemiological evidence that elevated baseline MPO and hs-CRP levels are both valuable predictors of MACEs in CHD patients. MPO and hs-CRP would prompt the progression of atherosclerosis and development from SAP to ACS.
基金Educational and Technological Foundation for Excellent Talents of Guizhou Province, No. 2005(25)
文摘BACKGROUND： Cerebral infarction is poorly treated due to neuronal necrosis and secondary pathophysiological changes; for example, free radical production and inflammatory reactions. OBJECTIVE： To detect the levels of high-sensitivity C-reactive protein （hs-CRP）, interleukin-6 （IL-6）, and tumor necrosis factor- a （TNF- α ） in elderly males with cerebral infarction. DESIGN： Non-randomized current control study. SETTING： Cadre Medical Department, Guizhou Provincial People＇s Hospital. PARTICIPANTS： Forty elderly males （65-89 years old） with cerebral infarction were selected from Cadre Medical Department, Guizhou Provincial People＇s Hospital from February 2004 to December 2006. All patients met the diagnostic criteria of cerebral infarction modified at the 4th National Cerebrovascular Disease Academic Meeting, and were diagnosed on the basis of CT or MRI tests. Furthermore, 35 elderly male inpatients （65-87 years old） without cerebral infarction were selected as the control group. Included subjects provided confirmed consent and did not have heart disease, diabetes mellitus, lipid disorder, acute trauma, infection, rheumatism, or other inflammatory diseases. The study was approved by the local ethics committee. There were no significant differences in age, blood pressure, and lipid levels between the cerebral infarction group and the control group （P 〉 0.05）, and this suggested that the baseline data of both groups were comparable. METHODS： Fasting venous blood was drawn from cerebral infarction patients 24 hours after cerebral infarction attack and from control subjects 24 hours after hospitalization. A latex-enhanced immunoturbidimetric assay and an enzyme-linked immunosorbent assay were used to detect the levels of hs-CRP, IL-6, and TNF- α in the serum. MAIN OUTCOME MEASURES： The levels of hs-CRP, 1L-6, and TNF- α in the serum in both groups. RESULTS： Forty cerebral infarction patients and thirty-five control subjects were included in the final analysis without any loss. Levels of hs-CRP, IL-6, and TNF-α in the cerebral infarction group were significantly higher than those in the control group （P 〈 0.01 ）. CONCLUSION： Levels of serum inflammatory reactive factors are increased in elderly males with cerebral infarction.
文摘Voltage dip is one of the detrimental power quality problems that can lead to huge financial losses in industries. Its economic impact is not only associated with the quality of the supply but also with sensitivity of electronic controls and equipment of the industry which are susceptible to voltage dips. Mitigating solutions are available but the choice depends on the careful assessment of the economic impact of voltage dips and economic gains of solutions. This paper presents an approach for estimating the economic cost of voltage dips based on sensitivity analysis. The voltage-tolerance curves of the sensitive equipment are obtained from experimental tests under different conditions. From the behavior and interaction of process equipment, different failure modes and economic sensitivity density are determined for different types of voltage dips. Voltage events monitored in the MV-network for several years are assessed to determine the frequency and severity of voltage dips at the customer terminal. The economic values of equipment and processes are assessed to get insight into alternative solutions with more rewarding measures. Then, cost-benefit analysis is performed to compare the economic gains of solutions protecting equipment or processes showing more rewarding economic values.
基金supported by National Natural Science Founda on of China (70533010)NIH grant # 5R24 TW 007988the Fogarty Interna onal Clinical Research Scholars Support Center at Vanderbilt-AAMC
文摘Objective To describe the distribution of plasma high sensitivity C-reactive protein （hsCRP） and explore the relationship between hsCRP and metabolic risk factors among residents living in longevity areas of China. Methods 268 individuals aged between 40 and 59 years and 506 individuals aged over 90 years were selected from 5 longevity areas of China to participate in a cross section longitudinal cohort study. The participants were interviewed with general health related questionnaire to collect their demographic, behavioral and lifestyle data, as well as their chronic conditions, and meanwhile their physical and biomedical parameters including waist circumference （WC）, blood pressure （BP）, hsCRP, plasma lipids, and fasting blood glucose （FBG） were measured. Results The median of hsCRP was 0.99 mg/L in the middle-aged group and 2.76 mg/L in the oldest old group. No significant gender difference was observed between the above two groups. Among the oldest old individuals, 36.56% had an hsCRP level 〉3.0 mg/L. The prevalence of high hsCRP was 26.79% in the middle-aged group. The results of stepwise multiple linear regression analyses showed that HDL-C was independently associated with In （hsCRP） concentration in the middle-aged group, whereas In （TG）, HDL-C and FBG were correlated after adjustment for gender, study site, smoking, drinking, education and BMI in the oldest old group. Conclusion HDL-C is a stronger predictor of elevated hsCRP than other metabolic factors in the middle-aged population. For the oldest old persons, high TG, low HDL-C, and FBG predict elevated plasma hsCRP.
文摘Biomarkers are early predictors of various disorders, circulating level of C-reactive protein is a sensitive biomarker of systemic inflammation and may also be associated with the development of diabetic, hepatic, and cardiovascular diseases. In the present study, we aimed to investigate the association between circulating levels of high sensitive C-reactive protein (hs-CRP) and various biomarkers for hepatic, diabetic, and cardiovascular health. The retrospective analysis included 438 individuals who were tested for these panels simultaneously at Vibrant America Clinical Laboratory. The study population included free-living individuals without any preexisting clinical conditions. Among the cardiovascular markers, a positive correlation and significant association was found between high levels of hs-CRP and serum levels of triglycerides (r = 0.0964, p −0.1423, p −0.1216, p < 0.0105) with circulating levels of hs-CRP. Among all the diabetic markers, glucose (r = 0.1547, p < 0.0011) and glycated serum protein (r = 0.1725, p < 0.0003) were positively correlated with circulating hs-CRP. In the hepatic panel, AST, a transaminase that plays a vital role in amino acid metabolism, was found to have a strong positive correlation with hs-CRP (r = 0.2139, p < 0.0001). In conclusion, the results clearly show the association of hs-CRP with diabetic, hepatic, and cardiovascular risk factors indicating its central value as a key marker for several lifestyle-associated disorders.
基金supported by the Natural Science Foundation of Zhejiang Province,China(No.LY13H180007)
文摘This study was undertaken to investigate the correlation of the enhancement degree on contrast-enhanced ultrasound(CEUS) with the histopathology of carotid plaques and the serum high sensitive C-reactive protein(hs-CRP) levels in patients undergoing carotid endarterectomy(CEA). Carotid CEUS was performed preoperatively in 115 patients who would undergo CEA, and the enhancement degree of the carotid plaques was evaluated by both the visual semiquantitative analysis and the quantitative time-intensity curve analysis. Serum hs-CRP levels were detected using the particle-enhanced immunoturbidimetric assay also before the operation. Additionally, the carotid plaque samples were subjected to histopathological examination postoperatively. The density of neovessels and the number of macrophages in the plaques were assessed by immunohistochemistry. The results showed that among the 115 patients, grade 0 plaque contrast enhancement was noted in 35 patients, grade 1 in 48 patients and grade 2 in 32 patients. The degree of plaque enhancement, the density of neovessels, the number of macrophages, and the hs-CRP levels were highest in the grade 2 patients. Correlation analysis showed that the enhancement degree of the carotid plaques was closely related to the immunohistochemical parameters of the plaques and the serum hs-CRP levels. It was suggested that the carotid plaque enhancement on CEUS can be used to evaluate the vulnerability of carotid plaques.
文摘A process of preparing ZnO voltage sensitive ceramics doped with some oxides by coprecipitation was described in the paper. The thermal properties of ZnO nanometer powders and the current voltage characteristics of the ceramics have been investigated. The results showed that the six additive ZnO powders with hexagonal system were homogeneous grain size distribution in microstructure, the optimal reaction pH is 6.90±0.05, the temperature for calcining and sintering was at about 500 ℃ and 1100 ℃, respectively. The powders were also examined by SEM, IR and XRD etc, and the effect of doping La 2O 3 on the electrical properties of ZnO varistor was investigated too.
基金supported by the National Natural Science Foundation of China(Grant Nos.32372118 and 32188102)the Zhejiang Natural Science Foundation,China(Grant No.LZ25C130010)+1 种基金the Qian Qian Academician Workstation,and the specific research fund of the Innovation Platform for Academicians of Hainan Province,China(Grant No.YSPTZX202303)the Central Public-Interest Scientific Institution Basal Research Fund from Chinese Academy of Agricultural Sciences(Grant No.Y2025YC93)。
文摘Global warming poses a severe threat to rice production and food security.We identified a heat-sensitive mutant hs1 through largescale screening of an established rice mutant library,and subsequently cloned the corresponding gene HS1,which confers thermotolerance in rice.HS1 is localized to the chloroplast and functions by preserving chloroplast integrity under elevated temperatures through stabilizing the photosystem I subunit protein PsaC.Loss of HS1 function in the hs1 mutant leads to severe structural damage to the chloroplast under heat stress,accompanied by intracellular accumulation of reactive oxygen species(ROS),which in turn triggers DNA damage and leaf albinism,ultimately manifesting as a heat-sensitive phenotype.
文摘Objective:To explore the application value of neutrophil/lymphocyte ratio (NLR) combined with high sensitive C reactive protein (hs-CRP) in the evaluation of community acquired pneumonia (CAP). Methods:From November 2015 to October 2016, 58 cases of CAP patients admitted in our department were selected as research objects and were divided into low risk group and high risk group according to the PSI score and CURB-65 standard for evaluation. They were divided into improved group (48 cases) and death group (10 cases) according to prognosis. Hs-CRP was determined by immunoturbidimetric assay, procalcitonin (PCT) by immunofluorescence, NLR by count method of laser scattering, and white blood (WBC) was counted. The differences in WBC, PCT, NLR and hs-CRP between different risk groups were compared, and the correlation was evaluated using Spearman's rank correlation analysis method. The changes in indexes were observed in the improved and death cases. Results:The high risk group had higher NLR, PCT and hs-CRP than low risk group (P<0.05), while no significant difference was found in WBC (P>0.05). No correlation was found between NLR and WBC, while a strong correlation was found between hs-CRP and PCT. The WBC, PCT, NLR and hs-CRP levels were significantly lower in the improved group than the death group (P<0.05). Conclusions:NLR combined with hs-CRP, WBC, and PCT has a good assessment of the severity of CAR, and high levels of NLR, hs-CRP, WBC, and PCT predict the severity of the disease and poor prognosis.
基金Supported by the National Natural Science Foundation of China(21376018,21576014,21676011,21808007,and 21878011)the Fundamental Research Funds for the Central Universities(ZY1837)China Postdoctoral Science Foundation(2017M620587)
文摘Temperature inferential control (TIC) is studied for a reactive distillation column with double reactive sections (RDC-DRSs) processing a hypothetical two-stage consecutive reversible reaction (A + B■C + D, C + B■E + D with αD > αB > αC > αA > αE). Because of the complicated dynamic behaviors, the controlled stages by sensitivity analysis lead to great steady-state deviations (SSDs) in top and bottom product purities. Since TIC involves considerably reduced settling times in comparison with direct composition control, small SSDs in product qualities correspond generally to small transient deviations (TDs) in product qualities. An objective function that measures SSDs in product qualities is formulated to represent the performance of a TIC system and an iterative procedure is devised to search for the best control configuration. The application of the procedure to the RDC-DRS gives considerably suppressed TDs and SSDs in top and bottom product qualities as compared with the one by sensitivity analysis. The method is simpler in principle and less computationally intensive than the current practice. These striking outcomes show the effectiveness of the proposed principle for the development of TIC systems for complicated reactive distillation columns.
基金Supported by the Joint Foundation from Health Commission of Hubei Province(WJ2019H007)
文摘We developed a special methylene blue solution for staining of cervix shedding cells based on catalytic oxidizing chromogenic reaction, which shows a potential for cervical cancer cytology screening. We screened a total of 1 922 women for cervical cancer with the special methylene blue staining method and a conventional Pap smear method using cervix shedding cells. Then, the patients with positive indicators of the Pap smear or this special solution staining method were examined by the electron colposcopy and histopathological examination. Staining of cervical exfoliated cells with this reactive oxygen-based special solution showed that the number of positive cases was 140(7.28%). Among them, 21 cases showed dark green(1.09%), and 119 cases showed purple black(6.19%). The results of the Pap smear method showed that the number of positive cases was 123(6.40%), of which ASCUS was 105(5.46%), ASC-H was 5(0.26%), and LSIL was 9(0.47%), and HSIL was 4(0.21%). For cervical exfoliated cell special staining solution for screening cervical intraepithelial neoplasia(CIN-Ⅱ, CIN-Ⅲ) and cervical cancer, sensitivity was 83.33%, specificity was 65.52%, accuracy was 74.29%, missed diagnosis rate was 13.33%, positive coincidence rate was 51.43%, and the negative coincidence rate is 86.67%. Our results proved the value of this method for early screening of cervical cancer through clinical practice in China.
基金supported by State Grid Corporation of China,Projects under Grant 520626200031National Natural Science Foundation of China,No.51877200。
文摘Half-wavelength transmission can transmit large-scale renewable energy over very long distances.This paper proposes an improved steady-state voltage-control method for half-wavelength transmission systems considering largescale wind-power transmission.First,the unique voltage characteristics of half-wavelength lines are deduced based on the distributed parameter model.In the secondary voltage-control level,reactive power-transmission limits of half-wavelength lines are introduced as another control objective except for tracing the pilot bus voltage reference.Considering the uncertainty and fluctuation of wind power,the overvoltage risk-assessment method of half-wavelength lines is presented to determine specific voltage-control strategies.Simulation results demonstrate that the proposed voltage-control method delivers superior tracking performance according to a voltage reference value and prevents the overvoltage risk of halfwavelength lines effectively in different wind-power penetrations.
基金This work was supported by the National Key R&D Program of China(No.2017YFB0903100)Science and Technology Projects of State Grid Corporation of China(No.521104170043).
文摘Voltage sags in power system may lead to serious problems such as the off-grid of distributed generation and electrical equipment failures.As a novel type of power electronic equipment,a flexible multi-state switch(FMSS)is capable to support the voltage during the grid faults.In this paper,a voltage control strategy to support the voltage in a distribution network is proposed by introducing three-port FMSS.The positive-negative-sequence compensation(PNSC)scheme is adopted to control the active and reactive current.This control scheme eliminates active power oscillations at the port of voltage sags and reduces coupling oscillations of other ports.Based on the characteristics of the voltage support under PNSC scheme,two voltage support strategies are proposed.A proportional-integral controller is introduced to provide the reactive power references,which eliminates the errors when estimating the grid voltage and impedance.A current limiting scheme is adopted to keep the port current in a safe range by adjusting the active and reactive power references.The voltage support strategies in two different voltage sags are simulated,and results show the feasibility and effectiveness of the proposed control strategies.
