When the wind speed changes significantly in a permanent magnet synchronous wind power generation system,the maximum power point cannot be easily determined in a timely manner.This study proposes a maximum power refer...When the wind speed changes significantly in a permanent magnet synchronous wind power generation system,the maximum power point cannot be easily determined in a timely manner.This study proposes a maximum power reference signal search method based on fuzzy control,which is an improvement to the climbing search method.A neural network-based parameter regulator is proposed to address external wind speed fluctuations,where the parameters of a proportional-integral controller is adjusted to accurately monitor the maximum power point under different wind speed conditions.Finally,the effectiveness of this method is verified via Simulink simulation.展开更多
[Objective]The research aimed to evaluate vulnerability of the lightning disaster in Guizhou and conduct zoning. [Method]According to data of the lightning monitoring network and statistical data of the lightning disa...[Objective]The research aimed to evaluate vulnerability of the lightning disaster in Guizhou and conduct zoning. [Method]According to data of the lightning monitoring network and statistical data of the lightning disaster in Guizhou during 2007-2012,by combining economy and population situations in 9 cities of Guizhou,6 indicators were used to assess vulnerability of the lightning disaster: CG lightning intensity,strong CG lightning intensity,annual average occurrence frequency of the lightning disaster,GDP per capita,population intensity and casualties frequency. By constructing principal component,determining weighing and comprehensive assessment,vulnerability grade of the lightning disaster in Guizhou was divided. [Result]Guiyang was extremely high vulnerability zone,high vulnerability zone included Zunyi,Bijie and Liupanshui,moderate vulnerability zone included Anshun,Tongren and Qianxinan,Qiannan was low vulnerability zone,and Qiandongnan was extremely low vulnerability zone. Vulnerability distribution boundary of the lightning disaster in Guizhou was along northeast to southwest,and vulnerability of the lightning disaster gradually weakened from northwest to southeast. [Conclusion]The research provided scientific basis for preventing lightning disaster and reducing damage of the lightning disaster.展开更多
Malignant behaviors of brain gliomas include proliferation and infiltration. It remains unclear which behavior influences the status of adjacent corticospinal tracts. Diffusion tensor imaging can show the status of br...Malignant behaviors of brain gliomas include proliferation and infiltration. It remains unclear which behavior influences the status of adjacent corticospinal tracts. Diffusion tensor imaging can show the status of brain white matter fiber tracts. Ki-67 and CD44/matrix metalloproteinase 9 are sensitive markers for reflecting the proliferation and infiltration of tumor cells. The present study analyzed pre-operative diffusion tensor images of 24 patients with pathologically confirmed World Health Organization glioma (I-IV). We observed lapse, infiltration and destruction of the peri-tumor corticospinal tract following reconstruction, and simultaneously detected the expression of Ki-67, CD44/matrix metalloproteinase 9 in samples. Expression of CD44 and matrix metalloproteinase 9 was not significantly correlated to the status of the peri-tumor corticospinal tract (r = 1.597, 4.859; P = 0.450, 0.088), while Ki-67 expression significantly correlated to its status (r = 6.590, P = 0.037). These findings demonstrate that highly proliferative gliomas result in damage to the peripheral corticospinal tract.展开更多
BACKGROUND The recognized pattern of cervical lymph node metastasis(CLNM)of papillary thyroid carcinoma involves a stepwise route.Contralateral lymph node skip metastasis is very rare.In addition,the patient in our ca...BACKGROUND The recognized pattern of cervical lymph node metastasis(CLNM)of papillary thyroid carcinoma involves a stepwise route.Contralateral lymph node skip metastasis is very rare.In addition,the patient in our case report also suffered from a breast carcinoma accompanied by left supraclavicular lymphadenopathy,which made it difficult to distinguish the origin of the CLNM.Based on this case,we recommended that more detailed physical and imaging examinations are needed for patients with uncommon cervical lymphatic metastasis of primary cancer.CASE SUMMARY A 53-year-old women was admitted to the hospital for a neck mass in the left cervical region that had existed for 2 mo.The neck mass was suspected to be an enlarged lateral LN originating from papillary thyroid microcarcinoma of the contralateral thyroid lobe,according to ultrasound and ultrasound-guided fine needle aspiration biopsy.The patient underwent total thyroidectomy and radical cervical LN dissection.Postoperative pathology confirmed the diagnosis of papillary thyroid microcarcinoma with contralateral lymphatic skip metastasis.Unfortunately,a breast cancer was discovered 4 mo later,which was accompanied by ipsilateral supraclavicular LN metastasis.She accepted neoadjuvant chemotherapy and subsequent left modified radical mastectomy for treatment.The patient is currently receiving postoperative radiotherapy,and no local recurrence was observed in the 6-mo follow-up after surgery.CONCLUSIONWe present a rare case of papillary thyroid microcarcinoma with contralateral lymphatic skipmetastasis and breast cancer with supraclavicular lymphatic metastasis.展开更多
Numerous linear grooves have long been recognized as covering the surface of Phobos, but the mechanisms of their formation are still unclear. One possible mechanism is related to the largest crater on Phobos, the Stic...Numerous linear grooves have long been recognized as covering the surface of Phobos, but the mechanisms of their formation are still unclear. One possible mechanism is related to the largest crater on Phobos, the Stickney crater, whose impact ejecta may slide,roll, bounce, and engrave groove-like features on Phobos. When the launch velocity is higher than the escape velocity, the impact ejecta can escape Phobos. A portion of these high-velocity ejecta are dragged by the gravitational force of Mars, fall back, and reimpact Phobos.In this research, we numerically test the hypothesis that the orbital ejecta of the Stickney crater that reimpact Phobos could be responsible for a particular subset of the observed grooves on Phobos. We adopt impact hydrocode i SALE-2 D(impact-Simplified Arbitrary Lagrangian Eulerian, two-dimensional) to simulate the formation of the Stickney crater and track its impact ejecta, with a focus on orbital ejecta with launch velocities greater than the escape velocity of Phobos. The launch velocity distribution of the ejecta particles is then used to calculate their trajectories in space and determine their fates. For orbital ejecta reimpacting Phobos, we then apply the sliding boulder model to calculate the ejecta paths, which are compared with the observed groove distribution and length to search for causal relationships. Our ejecta trajectory calculations suggest that only ~1% of the orbital ejecta from the Stickney crater can reimpact Phobos. Applying the sliding boulder model, we predict ejecta sliding paths of 9-20 km in a westward direction to the east of the zone of avoidance, closely matching the observed grooves in that region. The best-fit model assumes an ejecta radius of ~150 m and a speed restitution coefficient of 0.3, consistent with the expected ejecta and regolith properties. Our calculations thus suggest the groove class located to the east of the zone of avoidance may have been caused by reimpact orbital ejecta from the Stickney crater.展开更多
[Objectives]To evaluate the effectiveness of Rain Classroom intelligent teaching in the course of Spring Water Tourism Resources.[Methods]The course of Spring Water Tourism Resources in the course of Overview of Touri...[Objectives]To evaluate the effectiveness of Rain Classroom intelligent teaching in the course of Spring Water Tourism Resources.[Methods]The course of Spring Water Tourism Resources in the course of Overview of Tourism Resources was taken as an example,the pre-class preparation,in-class teaching,and after-class evaluation links were designed separately through the Rain Classroom platform.Then,a questionnaire survey was carried out for the students of Spring Water Tourism Resources.[Results]About 58.3%of the students believed that the greatest advantage of using the Rain Classroom teaching platform is that the learning method is flexible and can improve the ability of independent learning;61.78%of students stated that playing 3D animation in the classroom has the best effect for learning different tourism resources;with the aid of the Rain Classroom platform,the communication between teachers and students becomes more timely,and the students' ability to deal with practical problems can be practiced.[Conclusions]This study is intended to build an intelligent classroom model suitable for tourism management department based on the Rain Classroom platform.It is recommended to promote and apply this model in the teaching of tourism management.展开更多
Intrahepatic cholestasis of pregnancy(ICP)is related to cholestatic disorder in pregnancy.Total urinary sulfated bile acids(SBAs)were found increased in ICP.We distinguished the metabolic profiling of urinary SBAs in ...Intrahepatic cholestasis of pregnancy(ICP)is related to cholestatic disorder in pregnancy.Total urinary sulfated bile acids(SBAs)were found increased in ICP.We distinguished the metabolic profiling of urinary SBAs in ICP to find potential biomarkers for the diagnosis and grading of ICP.The targeted metabolomics based on high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)was used to analyze urinary SBAs profiling in mild and severe ICP cases,as well as healthy controls.16 kinds of urinary SBAs were determined by HPLC-MS/MS.Sulfated dihydroxy glycine bile acid(di-GBA-S),glycine cholic acid 3-sulfate(GCA-3S),sulfated dihydroxy taurine bile acid(di-TBA-S)and taurine cholic acid 3-sulfate(TCA-3S)increased significantly in ICP group compared with the control group.Seven kinds of SBAs were significantly different(p<0.05)between the ICP group and the control group,with the variable importance in the projection(VIP)value more than one by the orthogonal partial least squares discriminant analysis(OPLS-DA).GCA-3S was well-suited to be used as the biomarker for the diagnosis of ICP with the sensitivity of 100%and specificity of 95.5%.A multi-variable logistic regression containing GCA-3S and di-GBA-S-1 was constructed to distinguish severe ICP from mild ICP,with the sensitivity of 94.4%and specificity of 100%.The developed HPLC-MS/MS method is suitable for the measurement of urinary SBAs profiling.Moreover,the urinary SBAs in the metabolomic profiling have the potential to be used as non-intrusive biomarkers for the diagnosis and grading of ICP.展开更多
A novel maximum power-point tracking approach is proposed based on studies investigating the output characteristics of photovoltaic(PV)systems under partial shading conditions.The existence of partially shaded conditi...A novel maximum power-point tracking approach is proposed based on studies investigating the output characteristics of photovoltaic(PV)systems under partial shading conditions.The existence of partially shaded conditions leads to the presence of several peaks on PV curves,which decrease the efficiency of conventional techniques.Hence,the proposed algorithm,which is based on the modified particle-swarm optimization(MPSO)technique,increases the output power of PV systems under such abnormal conditions and has a better performance compared to other methods.The proposed method is examined under several scenarios for partial shading condition and non-uniform irradiation levels using Matlab,and to investigate its effectiveness adequately,the results of the proposed method are compared with those of the neural network technique.The experimental results show that the proposed method can decrease the interference of the local maximum power-point to cause the PV system to operate at a global maximum power-point.The efficiency of the MPSO is achieved with the least number of steady-state oscillations under partial shading conditions compared with the neural network method.展开更多
The 1-D piston problem for the pressure gradient equations arising from the flux-splitting of the compressible Euler equations is considered. When the total variations of the initial data and the velocity of the pisto...The 1-D piston problem for the pressure gradient equations arising from the flux-splitting of the compressible Euler equations is considered. When the total variations of the initial data and the velocity of the piston are both sufficiently small, the author establishes the global existence of entropy solutions including a strong rarefaction wave without restriction on the strength by employing a modified wave front tracking method.展开更多
This paper is contributed to the structural stability of multi-wave configurations to Cauchy problem for the compressible non-isentropic Euler system with adiabatic exponentγ∈(1,3].Given some small BV perturbations ...This paper is contributed to the structural stability of multi-wave configurations to Cauchy problem for the compressible non-isentropic Euler system with adiabatic exponentγ∈(1,3].Given some small BV perturbations of the initial state,the author employs a modified wave front tracking method,constructs a new Glimm functional,and proves its monotone decreasing based on the possible local wave interaction estimates,then establishes the global stability of the multi-wave configurations,consisting of a strong 1-shock wave,a strong 2-contact discontinuity,and a strong 3-shock wave,without restrictions on their strengths.展开更多
Research into climate change and the development of human societies has received considerable attention[1,2].By comparing paleoclimate records with major historical events in human society,previous studies have found ...Research into climate change and the development of human societies has received considerable attention[1,2].By comparing paleoclimate records with major historical events in human society,previous studies have found that the development of human societies might be closely linked to climate change[3,4].In particular,large-scale hydrological changes caused by climate change have directly affected agricultural productivity and further caused population migration and social conflict.展开更多
基金supported partially by the National Natural Science Foundation of China under Grant 61503348the Hubei Provincial Natural Science Foundation of China under Grant 2015CFA010the 111 project under Grant B17040
文摘When the wind speed changes significantly in a permanent magnet synchronous wind power generation system,the maximum power point cannot be easily determined in a timely manner.This study proposes a maximum power reference signal search method based on fuzzy control,which is an improvement to the climbing search method.A neural network-based parameter regulator is proposed to address external wind speed fluctuations,where the parameters of a proportional-integral controller is adjusted to accurately monitor the maximum power point under different wind speed conditions.Finally,the effectiveness of this method is verified via Simulink simulation.
基金Supported by Youth Fund Item of Guizhou Meteorological Bureau(Qianqikehe QN[2012]13)
文摘[Objective]The research aimed to evaluate vulnerability of the lightning disaster in Guizhou and conduct zoning. [Method]According to data of the lightning monitoring network and statistical data of the lightning disaster in Guizhou during 2007-2012,by combining economy and population situations in 9 cities of Guizhou,6 indicators were used to assess vulnerability of the lightning disaster: CG lightning intensity,strong CG lightning intensity,annual average occurrence frequency of the lightning disaster,GDP per capita,population intensity and casualties frequency. By constructing principal component,determining weighing and comprehensive assessment,vulnerability grade of the lightning disaster in Guizhou was divided. [Result]Guiyang was extremely high vulnerability zone,high vulnerability zone included Zunyi,Bijie and Liupanshui,moderate vulnerability zone included Anshun,Tongren and Qianxinan,Qiannan was low vulnerability zone,and Qiandongnan was extremely low vulnerability zone. Vulnerability distribution boundary of the lightning disaster in Guizhou was along northeast to southwest,and vulnerability of the lightning disaster gradually weakened from northwest to southeast. [Conclusion]The research provided scientific basis for preventing lightning disaster and reducing damage of the lightning disaster.
基金Anhui Prov-ince Grant of Tackle Key Problems in Science and Technology, No. 07010302202
文摘Malignant behaviors of brain gliomas include proliferation and infiltration. It remains unclear which behavior influences the status of adjacent corticospinal tracts. Diffusion tensor imaging can show the status of brain white matter fiber tracts. Ki-67 and CD44/matrix metalloproteinase 9 are sensitive markers for reflecting the proliferation and infiltration of tumor cells. The present study analyzed pre-operative diffusion tensor images of 24 patients with pathologically confirmed World Health Organization glioma (I-IV). We observed lapse, infiltration and destruction of the peri-tumor corticospinal tract following reconstruction, and simultaneously detected the expression of Ki-67, CD44/matrix metalloproteinase 9 in samples. Expression of CD44 and matrix metalloproteinase 9 was not significantly correlated to the status of the peri-tumor corticospinal tract (r = 1.597, 4.859; P = 0.450, 0.088), while Ki-67 expression significantly correlated to its status (r = 6.590, P = 0.037). These findings demonstrate that highly proliferative gliomas result in damage to the peripheral corticospinal tract.
基金Supported by The Project of Shanghai Municipal Health Commission,No. 20214Y0223
文摘BACKGROUND The recognized pattern of cervical lymph node metastasis(CLNM)of papillary thyroid carcinoma involves a stepwise route.Contralateral lymph node skip metastasis is very rare.In addition,the patient in our case report also suffered from a breast carcinoma accompanied by left supraclavicular lymphadenopathy,which made it difficult to distinguish the origin of the CLNM.Based on this case,we recommended that more detailed physical and imaging examinations are needed for patients with uncommon cervical lymphatic metastasis of primary cancer.CASE SUMMARY A 53-year-old women was admitted to the hospital for a neck mass in the left cervical region that had existed for 2 mo.The neck mass was suspected to be an enlarged lateral LN originating from papillary thyroid microcarcinoma of the contralateral thyroid lobe,according to ultrasound and ultrasound-guided fine needle aspiration biopsy.The patient underwent total thyroidectomy and radical cervical LN dissection.Postoperative pathology confirmed the diagnosis of papillary thyroid microcarcinoma with contralateral lymphatic skip metastasis.Unfortunately,a breast cancer was discovered 4 mo later,which was accompanied by ipsilateral supraclavicular LN metastasis.She accepted neoadjuvant chemotherapy and subsequent left modified radical mastectomy for treatment.The patient is currently receiving postoperative radiotherapy,and no local recurrence was observed in the 6-mo follow-up after surgery.CONCLUSIONWe present a rare case of papillary thyroid microcarcinoma with contralateral lymphatic skipmetastasis and breast cancer with supraclavicular lymphatic metastasis.
基金supported by the Science and Technology Development Fund, Macao (Grant No. 0020/2021/A1)the National Natural Science Foundation of China (Grant No. 12173106)supported by the Science and Technology Development Fund, Macao (Grant No. 0079/2018/A2)
文摘Numerous linear grooves have long been recognized as covering the surface of Phobos, but the mechanisms of their formation are still unclear. One possible mechanism is related to the largest crater on Phobos, the Stickney crater, whose impact ejecta may slide,roll, bounce, and engrave groove-like features on Phobos. When the launch velocity is higher than the escape velocity, the impact ejecta can escape Phobos. A portion of these high-velocity ejecta are dragged by the gravitational force of Mars, fall back, and reimpact Phobos.In this research, we numerically test the hypothesis that the orbital ejecta of the Stickney crater that reimpact Phobos could be responsible for a particular subset of the observed grooves on Phobos. We adopt impact hydrocode i SALE-2 D(impact-Simplified Arbitrary Lagrangian Eulerian, two-dimensional) to simulate the formation of the Stickney crater and track its impact ejecta, with a focus on orbital ejecta with launch velocities greater than the escape velocity of Phobos. The launch velocity distribution of the ejecta particles is then used to calculate their trajectories in space and determine their fates. For orbital ejecta reimpacting Phobos, we then apply the sliding boulder model to calculate the ejecta paths, which are compared with the observed groove distribution and length to search for causal relationships. Our ejecta trajectory calculations suggest that only ~1% of the orbital ejecta from the Stickney crater can reimpact Phobos. Applying the sliding boulder model, we predict ejecta sliding paths of 9-20 km in a westward direction to the east of the zone of avoidance, closely matching the observed grooves in that region. The best-fit model assumes an ejecta radius of ~150 m and a speed restitution coefficient of 0.3, consistent with the expected ejecta and regolith properties. Our calculations thus suggest the groove class located to the east of the zone of avoidance may have been caused by reimpact orbital ejecta from the Stickney crater.
文摘[Objectives]To evaluate the effectiveness of Rain Classroom intelligent teaching in the course of Spring Water Tourism Resources.[Methods]The course of Spring Water Tourism Resources in the course of Overview of Tourism Resources was taken as an example,the pre-class preparation,in-class teaching,and after-class evaluation links were designed separately through the Rain Classroom platform.Then,a questionnaire survey was carried out for the students of Spring Water Tourism Resources.[Results]About 58.3%of the students believed that the greatest advantage of using the Rain Classroom teaching platform is that the learning method is flexible and can improve the ability of independent learning;61.78%of students stated that playing 3D animation in the classroom has the best effect for learning different tourism resources;with the aid of the Rain Classroom platform,the communication between teachers and students becomes more timely,and the students' ability to deal with practical problems can be practiced.[Conclusions]This study is intended to build an intelligent classroom model suitable for tourism management department based on the Rain Classroom platform.It is recommended to promote and apply this model in the teaching of tourism management.
基金The present work was supported by the Chongqing Postdoctoral Science Foundation(Xm201313)National Natural Science Foundation of China(81471473)Research Fund for the Doctoral Program of Higher Education of China(20115503110013).
文摘Intrahepatic cholestasis of pregnancy(ICP)is related to cholestatic disorder in pregnancy.Total urinary sulfated bile acids(SBAs)were found increased in ICP.We distinguished the metabolic profiling of urinary SBAs in ICP to find potential biomarkers for the diagnosis and grading of ICP.The targeted metabolomics based on high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)was used to analyze urinary SBAs profiling in mild and severe ICP cases,as well as healthy controls.16 kinds of urinary SBAs were determined by HPLC-MS/MS.Sulfated dihydroxy glycine bile acid(di-GBA-S),glycine cholic acid 3-sulfate(GCA-3S),sulfated dihydroxy taurine bile acid(di-TBA-S)and taurine cholic acid 3-sulfate(TCA-3S)increased significantly in ICP group compared with the control group.Seven kinds of SBAs were significantly different(p<0.05)between the ICP group and the control group,with the variable importance in the projection(VIP)value more than one by the orthogonal partial least squares discriminant analysis(OPLS-DA).GCA-3S was well-suited to be used as the biomarker for the diagnosis of ICP with the sensitivity of 100%and specificity of 95.5%.A multi-variable logistic regression containing GCA-3S and di-GBA-S-1 was constructed to distinguish severe ICP from mild ICP,with the sensitivity of 94.4%and specificity of 100%.The developed HPLC-MS/MS method is suitable for the measurement of urinary SBAs profiling.Moreover,the urinary SBAs in the metabolomic profiling have the potential to be used as non-intrusive biomarkers for the diagnosis and grading of ICP.
基金Supported by the Hubei Provincial Natural Science Foundation of China(2015CFA010)the Technology Project of State Grid Company“Soft Connection Mechanism and Modeling of Smart Grid Adapting to the Development of Global Energy Interconnection”the 111 Projects(B17040).
文摘A novel maximum power-point tracking approach is proposed based on studies investigating the output characteristics of photovoltaic(PV)systems under partial shading conditions.The existence of partially shaded conditions leads to the presence of several peaks on PV curves,which decrease the efficiency of conventional techniques.Hence,the proposed algorithm,which is based on the modified particle-swarm optimization(MPSO)technique,increases the output power of PV systems under such abnormal conditions and has a better performance compared to other methods.The proposed method is examined under several scenarios for partial shading condition and non-uniform irradiation levels using Matlab,and to investigate its effectiveness adequately,the results of the proposed method are compared with those of the neural network technique.The experimental results show that the proposed method can decrease the interference of the local maximum power-point to cause the PV system to operate at a global maximum power-point.The efficiency of the MPSO is achieved with the least number of steady-state oscillations under partial shading conditions compared with the neural network method.
基金supported by the National Natural Science Foundation of China(Nos.11626176,11701435)the Fundamental Research Funds for the Central Universities of China(Nos.2018IB015,2018IVB013)
文摘The 1-D piston problem for the pressure gradient equations arising from the flux-splitting of the compressible Euler equations is considered. When the total variations of the initial data and the velocity of the piston are both sufficiently small, the author establishes the global existence of entropy solutions including a strong rarefaction wave without restriction on the strength by employing a modified wave front tracking method.
基金supported by the National Natural Science Foundation of China(No.11701435)the Fundamental Research Funds for the Central Universities(WUT:2020IB018)。
文摘This paper is contributed to the structural stability of multi-wave configurations to Cauchy problem for the compressible non-isentropic Euler system with adiabatic exponentγ∈(1,3].Given some small BV perturbations of the initial state,the author employs a modified wave front tracking method,constructs a new Glimm functional,and proves its monotone decreasing based on the possible local wave interaction estimates,then establishes the global stability of the multi-wave configurations,consisting of a strong 1-shock wave,a strong 2-contact discontinuity,and a strong 3-shock wave,without restrictions on their strengths.
基金supported by the National Natural Science Foundation of China(41888101,41822707,and 41721002)the Fundamental Research Funds for the Central Universities+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB26000000)the China Postdoctoral Science Foundation(2022M713024)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2018498)。
文摘Research into climate change and the development of human societies has received considerable attention[1,2].By comparing paleoclimate records with major historical events in human society,previous studies have found that the development of human societies might be closely linked to climate change[3,4].In particular,large-scale hydrological changes caused by climate change have directly affected agricultural productivity and further caused population migration and social conflict.
