This research takes China-aided construction projects in Asia since the Belt and Road Initiative as examples to explore the applicability of Chinese architectural design standards in other Asian countries.So far,the s...This research takes China-aided construction projects in Asia since the Belt and Road Initiative as examples to explore the applicability of Chinese architectural design standards in other Asian countries.So far,the standards demonstrated the highest applicability in South Asia is the best followed by Southeast Asia.Chinese architectural design standards for educational buildings showed the highest applicability,followed by office,medical,and sports buildings.This study puts forward some strategies to improve the applicability of Chinese architectural design standards.These strategies include integrating regionalism and local cultural traditions,optimizing energy efficiency,and aligning designs with local usage habits.This study serves as a reference for similar projects in the future.展开更多
Objective: To evaluate the value of MSCT plain scan and enhanced CT in the diagnosis of thymic adenocarcinoma. Methods: From May 2013 to June 2018, 37 cases of MSCT plain scan and dual-phase enhanced scan of thymic ad...Objective: To evaluate the value of MSCT plain scan and enhanced CT in the diagnosis of thymic adenocarcinoma. Methods: From May 2013 to June 2018, 37 cases of MSCT plain scan and dual-phase enhanced scan of thymic adenocarcinoma were retrospectively analyzed. The location, shape, size, density (CT value), enhanced features, peripheral invasion and mediastinal lymph node metastasis of the lesions were observed. Results: All 37 cases of thymic adenocarcinoma were diagnosed by CT before operation, and all cases were diagnosed by pathology after operation as malignant tumors,including 28 cases of thoracic adenocarcinoma and 9 cases of invasive thymoma. All 28 cases of thymic adenocarcinoma were single lesion of anterior superior mediastinum. The maximum cross-section was located in the midline in 7 cases and on the mediastinal side in 21 cases with significant difference (P<0.05). All lesions were irregular lobulated. The minimum diameter of lesions was 2.1 cm and the maximum diameter was 8.6 cm. Soft tissue density was dominant in the solid part. All cases of thymic adenocarcinoma showed inhomogeneous, moderate and severe enhancement in the arterial and venous phase after enhancement. The degree of enhancement in the venous phase was higher than that in the arterial phase, and there was no enhancement in the irregular liquefied necrosis area. 26 cases had necrotic lesions, 21 cases had mediastinal lymph node metastasis, and 8 cases had invasion of adjacent pleura. 19 cases had mediastinal vessels and 0 cases had distant pleural metastases. Conclusion: MSCT plain scan combined with dual-phase enhanced CT is helpful to display the details and metastasis of thymic adenocarcinoma, improve the coincidence rate of CT diagnosis and pathological diagnosis, and reduce the misdiagnosis rate. To provide help for clinical diagnosis and treatment of thymic adenocarcinoma.展开更多
Apples are still manually harvested by workers using ladders and buckets.Though it is known that manual apple harvest would probably lead to occupational injuries(e.g.,back,neck,and shoulder strains),there has been li...Apples are still manually harvested by workers using ladders and buckets.Though it is known that manual apple harvest would probably lead to occupational injuries(e.g.,back,neck,and shoulder strains),there has been little research that focuses on identifying the awkward activities/postures of pickers during the harvest process.After categorizing apple harvest work into 12 activities,this study used the method of Rapid Upper Limb Assessment(RULA)to identify awkward postures/activities that occurred during apple harvest.Awkward activities confirmed include descending a ladder,dumping apples,picking high and low apples on a ladder as well as on the ground,and moving a ladder,with potential reasons for each awkward activity provided.Meanwhile,it was demonstrated that pickers spent approximately 64%of working time under awkward postures that would lead to occupational diseases.In addition,this study analyzed picker harvest efficiency in terms of general and detail manners.The general mode assessed harvest activity in terms of picking and non-picking,with results showing that pickers averagely spent 76%(±7%)of harvest time in picking apples.Further analysis evaluated picking activities in terms of reaching,detaching,and transporting apples,with results showing that pickers spent averagely 30%(±6%)of time in detaching apples,which is the value time during apple harvest.Furthermore,valuable picking time ratio was obtained as the multiplication of picking time ratio and detaching time ratio.With a valuable ratio of 22%(±5%),it theoretically demonstrated the low harvest efficiency of the traditional harvest method.Since a majority of the awkward activities and the low efficiency were because of the ladders/buckets,using a harvest-assist unit may be a potential solution.Additionally,more efforts should be spent on the development of innovative mechanism to replace worker in placing attached apples to the bucket.Once the time for transporting apples is eliminated,the time for reaching apples is also removed,indicating the harvest efficiency would be improved significantly.展开更多
The large leakage current of the roof arrester caused by the high‐frequency resonant overvoltage on the high‐speed train occurs intermittently,which will cause the arrester to overheat locally.In this work,the overh...The large leakage current of the roof arrester caused by the high‐frequency resonant overvoltage on the high‐speed train occurs intermittently,which will cause the arrester to overheat locally.In this work,the overheating issue of the arrester under Ultra Harmonics Overvoltage is studied.Then,the relationship between the active power and the voltage(including amplitude and frequency)of the arrester is investigated,and the impact mechanism of the harmonic voltage on the overheating fault of the arrester is analysed based on experiments in this work.It is found that the total leakage current of the arrester is proportional to the amplitude and frequency of the applied voltage.The internal resistance of the arrester is independent of the amplitude of the voltage,but it will decrease with the increase of the frequency.The main reason that leads to thermal breakdown of the arrester valve under high‐frequency harmonic voltage is the heating power elevation of the arrester valve.The research study can provide theoretical basis and data support for the design,type selection and monitoring of the high‐speed train roof arrester.展开更多
A new type of piecewise negative stiffness(NS)mechanism is designed and the relationship between the force and displacement is studied.At first,the prototype of the piecewise NS mechanism is established,and the stiffn...A new type of piecewise negative stiffness(NS)mechanism is designed and the relationship between the force and displacement is studied.At first,the prototype of the piecewise NS mechanism is established,and the stiffness characteristic of this mechanism is analyzed.Then,the piecewise NS mechanism is applied to dynamic vibration absorber(DVA)system to establish a dynamic model with the piecewise linearity.The differential motion equations are derived according to Newton's law of mechanics.The approximate analytical solution and the amplitude frequency curve of the system with the piecewise NS are obtained by means of the averaging method.The correctness of the analytical solution is proved by comparing with the numerical solution.In the end,the comparisons with two other traditional DVAs show that the system in this paper has better vibration reduction effect under the condition of harmonic excitation and random excitation.展开更多
基金Humanities and Social Science Research Project of Colleges and Universities in Hebei Province(BJS2022039)2022 Annual Project of Education Science Research 14th“Five-Year”Plan in Hebei Province(2203094)+1 种基金2017 New Engineering Research and Practice Project of Hebei Colleges and Universities(2017GJXGK041)Doctoral Fund of Tangshan Normal University(2022A04)。
文摘This research takes China-aided construction projects in Asia since the Belt and Road Initiative as examples to explore the applicability of Chinese architectural design standards in other Asian countries.So far,the standards demonstrated the highest applicability in South Asia is the best followed by Southeast Asia.Chinese architectural design standards for educational buildings showed the highest applicability,followed by office,medical,and sports buildings.This study puts forward some strategies to improve the applicability of Chinese architectural design standards.These strategies include integrating regionalism and local cultural traditions,optimizing energy efficiency,and aligning designs with local usage habits.This study serves as a reference for similar projects in the future.
文摘Objective: To evaluate the value of MSCT plain scan and enhanced CT in the diagnosis of thymic adenocarcinoma. Methods: From May 2013 to June 2018, 37 cases of MSCT plain scan and dual-phase enhanced scan of thymic adenocarcinoma were retrospectively analyzed. The location, shape, size, density (CT value), enhanced features, peripheral invasion and mediastinal lymph node metastasis of the lesions were observed. Results: All 37 cases of thymic adenocarcinoma were diagnosed by CT before operation, and all cases were diagnosed by pathology after operation as malignant tumors,including 28 cases of thoracic adenocarcinoma and 9 cases of invasive thymoma. All 28 cases of thymic adenocarcinoma were single lesion of anterior superior mediastinum. The maximum cross-section was located in the midline in 7 cases and on the mediastinal side in 21 cases with significant difference (P<0.05). All lesions were irregular lobulated. The minimum diameter of lesions was 2.1 cm and the maximum diameter was 8.6 cm. Soft tissue density was dominant in the solid part. All cases of thymic adenocarcinoma showed inhomogeneous, moderate and severe enhancement in the arterial and venous phase after enhancement. The degree of enhancement in the venous phase was higher than that in the arterial phase, and there was no enhancement in the irregular liquefied necrosis area. 26 cases had necrotic lesions, 21 cases had mediastinal lymph node metastasis, and 8 cases had invasion of adjacent pleura. 19 cases had mediastinal vessels and 0 cases had distant pleural metastases. Conclusion: MSCT plain scan combined with dual-phase enhanced CT is helpful to display the details and metastasis of thymic adenocarcinoma, improve the coincidence rate of CT diagnosis and pathological diagnosis, and reduce the misdiagnosis rate. To provide help for clinical diagnosis and treatment of thymic adenocarcinoma.
文摘Apples are still manually harvested by workers using ladders and buckets.Though it is known that manual apple harvest would probably lead to occupational injuries(e.g.,back,neck,and shoulder strains),there has been little research that focuses on identifying the awkward activities/postures of pickers during the harvest process.After categorizing apple harvest work into 12 activities,this study used the method of Rapid Upper Limb Assessment(RULA)to identify awkward postures/activities that occurred during apple harvest.Awkward activities confirmed include descending a ladder,dumping apples,picking high and low apples on a ladder as well as on the ground,and moving a ladder,with potential reasons for each awkward activity provided.Meanwhile,it was demonstrated that pickers spent approximately 64%of working time under awkward postures that would lead to occupational diseases.In addition,this study analyzed picker harvest efficiency in terms of general and detail manners.The general mode assessed harvest activity in terms of picking and non-picking,with results showing that pickers averagely spent 76%(±7%)of harvest time in picking apples.Further analysis evaluated picking activities in terms of reaching,detaching,and transporting apples,with results showing that pickers spent averagely 30%(±6%)of time in detaching apples,which is the value time during apple harvest.Furthermore,valuable picking time ratio was obtained as the multiplication of picking time ratio and detaching time ratio.With a valuable ratio of 22%(±5%),it theoretically demonstrated the low harvest efficiency of the traditional harvest method.Since a majority of the awkward activities and the low efficiency were because of the ladders/buckets,using a harvest-assist unit may be a potential solution.Additionally,more efforts should be spent on the development of innovative mechanism to replace worker in placing attached apples to the bucket.Once the time for transporting apples is eliminated,the time for reaching apples is also removed,indicating the harvest efficiency would be improved significantly.
基金supported by the Fundamental Research Funds for the Central Universities(2021JBM025)the National Natural Science Foundation of China(51907003).
文摘The large leakage current of the roof arrester caused by the high‐frequency resonant overvoltage on the high‐speed train occurs intermittently,which will cause the arrester to overheat locally.In this work,the overheating issue of the arrester under Ultra Harmonics Overvoltage is studied.Then,the relationship between the active power and the voltage(including amplitude and frequency)of the arrester is investigated,and the impact mechanism of the harmonic voltage on the overheating fault of the arrester is analysed based on experiments in this work.It is found that the total leakage current of the arrester is proportional to the amplitude and frequency of the applied voltage.The internal resistance of the arrester is independent of the amplitude of the voltage,but it will decrease with the increase of the frequency.The main reason that leads to thermal breakdown of the arrester valve under high‐frequency harmonic voltage is the heating power elevation of the arrester valve.The research study can provide theoretical basis and data support for the design,type selection and monitoring of the high‐speed train roof arrester.
基金The authors are grateful to the support by National Natural Science Foundation of China(No.U1934201 and 11772206).
文摘A new type of piecewise negative stiffness(NS)mechanism is designed and the relationship between the force and displacement is studied.At first,the prototype of the piecewise NS mechanism is established,and the stiffness characteristic of this mechanism is analyzed.Then,the piecewise NS mechanism is applied to dynamic vibration absorber(DVA)system to establish a dynamic model with the piecewise linearity.The differential motion equations are derived according to Newton's law of mechanics.The approximate analytical solution and the amplitude frequency curve of the system with the piecewise NS are obtained by means of the averaging method.The correctness of the analytical solution is proved by comparing with the numerical solution.In the end,the comparisons with two other traditional DVAs show that the system in this paper has better vibration reduction effect under the condition of harmonic excitation and random excitation.