With the continuous growth of the economy and the rapid pace of urbanization,the real estate sector has assumed an increasingly substantial role within the national economy.Ensuring the stable and sustainable developm...With the continuous growth of the economy and the rapid pace of urbanization,the real estate sector has assumed an increasingly substantial role within the national economy.Ensuring the stable and sustainable development of the real estate sector to maximize its societal and economic contributions has become a pressing issue.China,presently engaged in an extensive urbanization drive,places real estate development and sales as pivotal components in the broader real estate industry,significantly impacting the overall functionality of the real estate market.Real estate,being a comprehensive system encompassing land,housing,infrastructure,and other key elements,exerts a profound influence on people’s basic needs such as shelter,sustenance,and daily living.Its evolution directly shapes the trajectory of the national economy and social stability.Therefore,to foster the consistent and robust growth of China’s real estate economy,it is necessary to implement effective measures that entail a systematic and thorough analysis of the factors responsible for the fluctuations in China’s real estate economy.展开更多
To evaluate the regularity of resilient modulus for hot-mix asphalt(HMA)under large temperature fluctuations,back propagation(BP)neural network technology was used to analyze the continuous change of HMA resilient mod...To evaluate the regularity of resilient modulus for hot-mix asphalt(HMA)under large temperature fluctuations,back propagation(BP)neural network technology was used to analyze the continuous change of HMA resilient modulus.Firstly,based on the abundant data,the training model of HMA resilient modulus was established by using BP neural network technology.Subsequently,BP neural network prediction and regression analysis were performed,and the prediction model of HMA resilient modulus at different temperatures(50C to 60C)was obtained,which fully considered multi-factor and nonlinearity.Finally,the fitted theoretical model can be used to evaluate the HMA performance under the condition of large temperature fluctuations,and the rationality of theoretical model was verified by taking Harbin region as an example.It was found that the relationship between HMA resilient modulus and temperatures can be described by inverse tangent function.And the key parameters of theoretical model can be used to evaluate the continuous change characteristics of HMA resilient modulus with large temperature fluctuations.The results can further improve the HMA performance evaluation system and have certain theoretical value.展开更多
When boost power factor correction(PFC) circuit works with large scale load fluctuations, it is easy to cause a higher total harmonic distortion and a lower power factor because of traditional controllers and inductor...When boost power factor correction(PFC) circuit works with large scale load fluctuations, it is easy to cause a higher total harmonic distortion and a lower power factor because of traditional controllers and inductor current mode. To solve this problem, this paper proposes a PFC control system, which can operate with load fluctuations up to 1 000 W by using duty cycle feed-forward control theory to achieve smooth switching mode. The duty cycles in the next period of the control system are pre-estimated in the current cycle, which enhances the speeds of AD samplers and switching frequency, and reduces the cost and volume of the equipment to some extent. Introductions of system decoupling and feed-forward of input-voltage greatly improve the system performance. Both theoretical simulation and experimental results prove the advantage of the proposed scheme.展开更多
In this study,we examined the thermal fluctuations,deflection angle,and greybody factor of a high-dimensional Schwarzschild black hole in scalar-tensor-vector gravity(STVG).We calculated some thermodynamic quantities ...In this study,we examined the thermal fluctuations,deflection angle,and greybody factor of a high-dimensional Schwarzschild black hole in scalar-tensor-vector gravity(STVG).We calculated some thermodynamic quantities related to the correction of the black hole entropy caused by thermal fluctuations and discussed the effect of the correction parameters on these quantities.By analyzing the changes in the corrected specific heat,we found that thermal fluctuations made the small black hole more stable.It is worth noting that the STVG parameter did not affect the thermodynamic stability of this black hole.Additionally,by utilizing the Gauss-Bonnet theorem,the deflection angle was obtained in the weak field limit,and the effects of the two parameters on the results were visualized.Finally,we calculated the bounds on the greybody factor of a massless scalar field.We observed that as the STVG parameter around the black hole increased,the weak deflection angle became larger,and more scalar particles can reach infinity.However,the spacetime dimension has the opposite effect on the STVG parameter on the weak deflection angle and greybody factor.展开更多
目的:探讨急性脑梗死(acute cerebral infarction,ACI)溶栓患者术后临床症状反复发作的相关影响因素。方法:采用回顾性调查方法对2019年1月—2023年2月在张家港市第二人民医院神经内科诊治的90例ACI溶栓患者资料进行分析,以术后出现偏...目的:探讨急性脑梗死(acute cerebral infarction,ACI)溶栓患者术后临床症状反复发作的相关影响因素。方法:采用回顾性调查方法对2019年1月—2023年2月在张家港市第二人民医院神经内科诊治的90例ACI溶栓患者资料进行分析,以术后出现偏瘫、失语等临床症状反复发作的56例(62.22%)为观察组,未出现临床症状反复发作的34例(37.78%)为对照组,并对其进行单因素分析、logistic回归分析及受试者工作特征(receiver operating characteristic,ROC)曲线分析,研究ACI溶栓患者术后临床症状反复发作的相关因素。结果:单因素分析分析结果显示,两组性别、年龄、吸烟史、高血压史、糖尿病史、发病时间、血清生化指标比较,差异无统计学意义(P>0.05);两组美国国立卫生研究院卒中量表(National Institute of Health stroke scale,NIHSS)评分、心房颤动、梗死部位水平比较,差异有统计学意义(P<0.05)。logistic回归分析结果显示,NIHSS评分、心房颤动及梗死部位为ACI溶栓患者术后临床症状反复发作的独立危险因素(P<0.05)。ROC曲线分析结果显示,NIHSS评分、心房颤动及梗死部位的ROC曲线下面积(area under curve,AUC)分别为0.899、0.637、0.654,敏感度较高。结论:ACI溶栓患者术后临床症状反复发作与脑卒中神经缺损程度、心房颤动及梗死部位有关。展开更多
基金Anhui Provincial Department of Education’s Key Project of Continuing Education and Teaching Reform in Colleges and Universities“Construction of Higher Education Continuing Education Reform Demonstration Base”(2021jxjy020)Anhui Provincial Department of Education’s Key Project of Continuing Education and Teaching Reform in Colleges and Universities“Research and Practice on the Construction and Development of Lifelong Education Credit Bank in Anhui Province”(2021jxjy019)Anhui Provincial Colleges and Universities Scientific Research Key Project“Research and Practice on the Learning Achievements Certification System Based on the‘College Colleges-Credit Bank-Technical Colleges’Linkage Mechanism”(2022AH052676).
文摘With the continuous growth of the economy and the rapid pace of urbanization,the real estate sector has assumed an increasingly substantial role within the national economy.Ensuring the stable and sustainable development of the real estate sector to maximize its societal and economic contributions has become a pressing issue.China,presently engaged in an extensive urbanization drive,places real estate development and sales as pivotal components in the broader real estate industry,significantly impacting the overall functionality of the real estate market.Real estate,being a comprehensive system encompassing land,housing,infrastructure,and other key elements,exerts a profound influence on people’s basic needs such as shelter,sustenance,and daily living.Its evolution directly shapes the trajectory of the national economy and social stability.Therefore,to foster the consistent and robust growth of China’s real estate economy,it is necessary to implement effective measures that entail a systematic and thorough analysis of the factors responsible for the fluctuations in China’s real estate economy.
基金appreciate support from the projects of Science and Technology Project of Transportation Department of Heilongjiang Province(No.HJK2019B009)the Fundamental Research Funds for the Cornell University(No.2572021AW10)the Ludong Uni-versity to Introduce Talents Research Start-up Funding Project(No.20240050).
文摘To evaluate the regularity of resilient modulus for hot-mix asphalt(HMA)under large temperature fluctuations,back propagation(BP)neural network technology was used to analyze the continuous change of HMA resilient modulus.Firstly,based on the abundant data,the training model of HMA resilient modulus was established by using BP neural network technology.Subsequently,BP neural network prediction and regression analysis were performed,and the prediction model of HMA resilient modulus at different temperatures(50C to 60C)was obtained,which fully considered multi-factor and nonlinearity.Finally,the fitted theoretical model can be used to evaluate the HMA performance under the condition of large temperature fluctuations,and the rationality of theoretical model was verified by taking Harbin region as an example.It was found that the relationship between HMA resilient modulus and temperatures can be described by inverse tangent function.And the key parameters of theoretical model can be used to evaluate the continuous change characteristics of HMA resilient modulus with large temperature fluctuations.The results can further improve the HMA performance evaluation system and have certain theoretical value.
基金Supported by the National Basic Research Program of China("973"Program,No.2009CB219700)
文摘When boost power factor correction(PFC) circuit works with large scale load fluctuations, it is easy to cause a higher total harmonic distortion and a lower power factor because of traditional controllers and inductor current mode. To solve this problem, this paper proposes a PFC control system, which can operate with load fluctuations up to 1 000 W by using duty cycle feed-forward control theory to achieve smooth switching mode. The duty cycles in the next period of the control system are pre-estimated in the current cycle, which enhances the speeds of AD samplers and switching frequency, and reduces the cost and volume of the equipment to some extent. Introductions of system decoupling and feed-forward of input-voltage greatly improve the system performance. Both theoretical simulation and experimental results prove the advantage of the proposed scheme.
基金supported by the National Natural Science Foundation of China (Grant No.12065012)Yunnan Fundamental Research Projects (202301AS070029)Yunnan High-Level Talent Training Support Plan Young&Elite Talents Project (Grant No.YNWR-QNBJ-2018-360)。
文摘In this study,we examined the thermal fluctuations,deflection angle,and greybody factor of a high-dimensional Schwarzschild black hole in scalar-tensor-vector gravity(STVG).We calculated some thermodynamic quantities related to the correction of the black hole entropy caused by thermal fluctuations and discussed the effect of the correction parameters on these quantities.By analyzing the changes in the corrected specific heat,we found that thermal fluctuations made the small black hole more stable.It is worth noting that the STVG parameter did not affect the thermodynamic stability of this black hole.Additionally,by utilizing the Gauss-Bonnet theorem,the deflection angle was obtained in the weak field limit,and the effects of the two parameters on the results were visualized.Finally,we calculated the bounds on the greybody factor of a massless scalar field.We observed that as the STVG parameter around the black hole increased,the weak deflection angle became larger,and more scalar particles can reach infinity.However,the spacetime dimension has the opposite effect on the STVG parameter on the weak deflection angle and greybody factor.
文摘目的:探讨急性脑梗死(acute cerebral infarction,ACI)溶栓患者术后临床症状反复发作的相关影响因素。方法:采用回顾性调查方法对2019年1月—2023年2月在张家港市第二人民医院神经内科诊治的90例ACI溶栓患者资料进行分析,以术后出现偏瘫、失语等临床症状反复发作的56例(62.22%)为观察组,未出现临床症状反复发作的34例(37.78%)为对照组,并对其进行单因素分析、logistic回归分析及受试者工作特征(receiver operating characteristic,ROC)曲线分析,研究ACI溶栓患者术后临床症状反复发作的相关因素。结果:单因素分析分析结果显示,两组性别、年龄、吸烟史、高血压史、糖尿病史、发病时间、血清生化指标比较,差异无统计学意义(P>0.05);两组美国国立卫生研究院卒中量表(National Institute of Health stroke scale,NIHSS)评分、心房颤动、梗死部位水平比较,差异有统计学意义(P<0.05)。logistic回归分析结果显示,NIHSS评分、心房颤动及梗死部位为ACI溶栓患者术后临床症状反复发作的独立危险因素(P<0.05)。ROC曲线分析结果显示,NIHSS评分、心房颤动及梗死部位的ROC曲线下面积(area under curve,AUC)分别为0.899、0.637、0.654,敏感度较高。结论:ACI溶栓患者术后临床症状反复发作与脑卒中神经缺损程度、心房颤动及梗死部位有关。
