为了利用X射线吸收精细结构(X-ray absorption fine structure,XAFS)谱学技术开展热化学反应动力学研究,在上海光源X射线吸收精细结构谱学线站(BL14W1)开展了时间分辨热化学原位XAFS方法的研究。采用自主研制的数据采集设备解决了时间分...为了利用X射线吸收精细结构(X-ray absorption fine structure,XAFS)谱学技术开展热化学反应动力学研究,在上海光源X射线吸收精细结构谱学线站(BL14W1)开展了时间分辨热化学原位XAFS方法的研究。采用自主研制的数据采集设备解决了时间分辨XAFS技术中不同类型信号同步触发和同步采集的问题,实现了数据间的精准匹配。在单色器转速为720"/s、数据采集设备采样率为2MS/s、数据长度为1200eV的条件下,获得了一个9.6s的Cu标样的数据谱,通过与常规XAFS数据和标准XAFS数据进行对比,结果表明本文得到的时间分辨XAFS实验系统具有良好的准确性、分辨率和信噪比。在此基础上,进一步结合线站自主研制的原位装置开展了时间分辨热化学原位XAFS方法,并利用高温常压原位装置开展了CuO还原为金属Cu的验证性实验。在230℃恒温氢气气氛下30min内观测到Cu吸收边能量逐渐向低能量处偏移,同时它位于8998eV的主峰强度逐渐减弱并且劈裂为双峰结构,出现明显的金属Cu的特征。实验结果表明此方法达到了捕获物质动态演化过程的预期目的,在拓展XAFS谱学实验平台的同时,为热化学反应的动力学过程研究提供了一种强大的实验手段。展开更多
Understanding the effects of microwave irradiation and thermal treatment on the dynamic compression and fragmentation properties of rocks is essential to quantify energy consumption in rock engineering.In this study,F...Understanding the effects of microwave irradiation and thermal treatment on the dynamic compression and fragmentation properties of rocks is essential to quantify energy consumption in rock engineering.In this study,Fangshan granite(FG)specimens were exposed to microwave irradiation and heat treatment.The damage of FG specimens induced by these two methods was compared using X-ray CT scanning and ultrasonic wave method.The temperatures of FG after microwave irradiation and thermal treatment were effectively evaluated using a newly proposed technique.A novelty method for precisely determining the geometric features of fragments is developed to estimate the fragmentation energy.Thus,the dynamic uniaxial compressive strength(UCS),the dynamic fragmentation characteristics,and the fragmentation energy of FG after these two pretreatment methods can be reasonably compared.The noticeable distinction of loading rate effect on the dynamic UCS of FG between these two pretreatment methods is first observed.A relationship is established between the dynamic UCS and the damage induced by microwave irradiation and heat treatment.Moreover,fragmentation energy fan analysis is introduced to accurately compare the fragmentation properties of FG after two pretreatment methods in dynamic compression tests.展开更多
Urban underground pipelines are an important infrastructure in cities,and timely investigation of problems in underground pipelines can help ensure the normal operation of cities.Owing to the growing demand for defect...Urban underground pipelines are an important infrastructure in cities,and timely investigation of problems in underground pipelines can help ensure the normal operation of cities.Owing to the growing demand for defect detection in urban underground pipelines,this study developed an improved defect detection method for urban underground pipelines based on fully convolutional one-stage object detector(FCOS),called spatial pyramid pooling-fast(SPPF)feature fusion and dual detection heads based on FCOS(SDH-FCOS)model.This study improved the feature fusion component of the model network based on FCOS,introduced an SPPF network structure behind the last output feature layer of the backbone network,fused the local and global features,added a top-down path to accelerate the circulation of shallowinformation,and enriched the semantic information acquired by shallow features.The ability of the model to detect objects with multiple morphologies was strengthened by introducing dual detection heads.The experimental results using an open dataset of underground pipes show that the proposed SDH-FCOS model can recognize underground pipe defects more accurately;the average accuracy was improved by 2.7% compared with the original FCOS model,reducing the leakage rate to a large extent and achieving real-time detection.Also,our model achieved a good trade-off between accuracy and speed compared with other mainstream methods.This proved the effectiveness of the proposed model.展开更多
Background:To observe the changes in serum calcitonin levels after application of different surgical methods for primary medullary thyroid microcarcinoma(MTMC)and explore a more reasonable surgical method.Methods:A re...Background:To observe the changes in serum calcitonin levels after application of different surgical methods for primary medullary thyroid microcarcinoma(MTMC)and explore a more reasonable surgical method.Methods:A retrospective analysis of 36 patients with MTMC,16 in group A and 20 in group B,was performed.In group A,tumors were single and confined to the thyroid lobe,and thyroid lobectomy with isthmusectomy was performed.In group B,tumors were in the isthmus or invaded the thyroid gland,or there were multiple foci in bilateral lobes,and patients with primary foci underwent total thyroidectomy.The median follow-up time was 3.6 years.Clinical and pathological characteristics and changes in serum calcitonin(CTn)and carcinoembryonic antigen levels after the surgery were compared between the 2 groups.Results:The difference in the biochemical cure rate after surgery was statistically significant between patients with preoperative serum calcitonin levels<150 pg/mL and≥150 pg/mL(P<0.01).No significant differences in the biochemical cure rates and serum calcitonin levels were noted at different time points after surgery between group A and group B(P>0.05).One recurrence and metastasis were observed in each group after surgery.Conclusions:After performing different surgical methods for the primary foci of MTMC,the changes in serum calcitonin and carcinoembryonic antigen levels are similar.Especially for patients with single foci confined to the thyroid lobe without lateral cervical lymph node metastasis and with serum calcitonin levels<150 pg/mL,the unilateral thyroid lobectomy with isthmectomy can achieve the same therapeutic effect and biochemical cure rate as total thyroidectomy.展开更多
The construction of early childhood curriculum resources serves as a vital vehicle and precondition for the implementation of collective teaching activities in kindergartens.However,traditional curriculum resources ba...The construction of early childhood curriculum resources serves as a vital vehicle and precondition for the implementation of collective teaching activities in kindergartens.However,traditional curriculum resources based on graphic language or the linguistic descriptions of early childhood educators often fail to provide children with an immersive experience during collective teaching activities,leading to a lack of initiative and interest in learning.This paper discusses the methods for building a kindergarten curriculum resource library and,based on this foundation,employs virtual reality technology for three-dimensional modeling of the library to enrich the curriculum resources in kindergartens.Furthermore,this paper proposes to train early childhood educators in virtual reality technology to enhance their abilities to operate and utilize virtual reality equipment,which can emphasize the children’s central role in the learning process,better achieve educational goals,and improve teaching outcomes.展开更多
文摘为了利用X射线吸收精细结构(X-ray absorption fine structure,XAFS)谱学技术开展热化学反应动力学研究,在上海光源X射线吸收精细结构谱学线站(BL14W1)开展了时间分辨热化学原位XAFS方法的研究。采用自主研制的数据采集设备解决了时间分辨XAFS技术中不同类型信号同步触发和同步采集的问题,实现了数据间的精准匹配。在单色器转速为720"/s、数据采集设备采样率为2MS/s、数据长度为1200eV的条件下,获得了一个9.6s的Cu标样的数据谱,通过与常规XAFS数据和标准XAFS数据进行对比,结果表明本文得到的时间分辨XAFS实验系统具有良好的准确性、分辨率和信噪比。在此基础上,进一步结合线站自主研制的原位装置开展了时间分辨热化学原位XAFS方法,并利用高温常压原位装置开展了CuO还原为金属Cu的验证性实验。在230℃恒温氢气气氛下30min内观测到Cu吸收边能量逐渐向低能量处偏移,同时它位于8998eV的主峰强度逐渐减弱并且劈裂为双峰结构,出现明显的金属Cu的特征。实验结果表明此方法达到了捕获物质动态演化过程的预期目的,在拓展XAFS谱学实验平台的同时,为热化学反应的动力学过程研究提供了一种强大的实验手段。
基金supported by the National Natural Science Foundation of China(Nos.51879184 and 12172253).
文摘Understanding the effects of microwave irradiation and thermal treatment on the dynamic compression and fragmentation properties of rocks is essential to quantify energy consumption in rock engineering.In this study,Fangshan granite(FG)specimens were exposed to microwave irradiation and heat treatment.The damage of FG specimens induced by these two methods was compared using X-ray CT scanning and ultrasonic wave method.The temperatures of FG after microwave irradiation and thermal treatment were effectively evaluated using a newly proposed technique.A novelty method for precisely determining the geometric features of fragments is developed to estimate the fragmentation energy.Thus,the dynamic uniaxial compressive strength(UCS),the dynamic fragmentation characteristics,and the fragmentation energy of FG after these two pretreatment methods can be reasonably compared.The noticeable distinction of loading rate effect on the dynamic UCS of FG between these two pretreatment methods is first observed.A relationship is established between the dynamic UCS and the damage induced by microwave irradiation and heat treatment.Moreover,fragmentation energy fan analysis is introduced to accurately compare the fragmentation properties of FG after two pretreatment methods in dynamic compression tests.
基金supported by the National Natural Science Foundation of China under Grant No.61976226the Research and Academic Team of South-CentralMinzu University under Grant No.KTZ20050.
文摘Urban underground pipelines are an important infrastructure in cities,and timely investigation of problems in underground pipelines can help ensure the normal operation of cities.Owing to the growing demand for defect detection in urban underground pipelines,this study developed an improved defect detection method for urban underground pipelines based on fully convolutional one-stage object detector(FCOS),called spatial pyramid pooling-fast(SPPF)feature fusion and dual detection heads based on FCOS(SDH-FCOS)model.This study improved the feature fusion component of the model network based on FCOS,introduced an SPPF network structure behind the last output feature layer of the backbone network,fused the local and global features,added a top-down path to accelerate the circulation of shallowinformation,and enriched the semantic information acquired by shallow features.The ability of the model to detect objects with multiple morphologies was strengthened by introducing dual detection heads.The experimental results using an open dataset of underground pipes show that the proposed SDH-FCOS model can recognize underground pipe defects more accurately;the average accuracy was improved by 2.7% compared with the original FCOS model,reducing the leakage rate to a large extent and achieving real-time detection.Also,our model achieved a good trade-off between accuracy and speed compared with other mainstream methods.This proved the effectiveness of the proposed model.
基金supported by a grant from the Gansu Provincial Nature Foundation Project(no.23URRA2346).
文摘Background:To observe the changes in serum calcitonin levels after application of different surgical methods for primary medullary thyroid microcarcinoma(MTMC)and explore a more reasonable surgical method.Methods:A retrospective analysis of 36 patients with MTMC,16 in group A and 20 in group B,was performed.In group A,tumors were single and confined to the thyroid lobe,and thyroid lobectomy with isthmusectomy was performed.In group B,tumors were in the isthmus or invaded the thyroid gland,or there were multiple foci in bilateral lobes,and patients with primary foci underwent total thyroidectomy.The median follow-up time was 3.6 years.Clinical and pathological characteristics and changes in serum calcitonin(CTn)and carcinoembryonic antigen levels after the surgery were compared between the 2 groups.Results:The difference in the biochemical cure rate after surgery was statistically significant between patients with preoperative serum calcitonin levels<150 pg/mL and≥150 pg/mL(P<0.01).No significant differences in the biochemical cure rates and serum calcitonin levels were noted at different time points after surgery between group A and group B(P>0.05).One recurrence and metastasis were observed in each group after surgery.Conclusions:After performing different surgical methods for the primary foci of MTMC,the changes in serum calcitonin and carcinoembryonic antigen levels are similar.Especially for patients with single foci confined to the thyroid lobe without lateral cervical lymph node metastasis and with serum calcitonin levels<150 pg/mL,the unilateral thyroid lobectomy with isthmectomy can achieve the same therapeutic effect and biochemical cure rate as total thyroidectomy.
基金Educational Science Research Program of Anhui(JK22007)Key Project on Anhui Provincial Humanities and Social Sciences by Colleges and Universities(SK2019A0373)+1 种基金Teaching Research Project of Anhui Province(2022jyxm927)Jiangxi Postdoctoral Foundation(2021RC04)。
文摘The construction of early childhood curriculum resources serves as a vital vehicle and precondition for the implementation of collective teaching activities in kindergartens.However,traditional curriculum resources based on graphic language or the linguistic descriptions of early childhood educators often fail to provide children with an immersive experience during collective teaching activities,leading to a lack of initiative and interest in learning.This paper discusses the methods for building a kindergarten curriculum resource library and,based on this foundation,employs virtual reality technology for three-dimensional modeling of the library to enrich the curriculum resources in kindergartens.Furthermore,this paper proposes to train early childhood educators in virtual reality technology to enhance their abilities to operate and utilize virtual reality equipment,which can emphasize the children’s central role in the learning process,better achieve educational goals,and improve teaching outcomes.
文摘高质量发展是全面建设社会主义现代化国家的首要任务,也是中国式现代化的本质要求。文章以2009—2021年31省(市)面板数据为样本,利用熵权Topsis法构建“五位一体”高质量发展评价指标,将倾向匹配得分法和双重差分模型相结合(Propensity Score Matching-Differences in Differences,PSM-DID),探索长江经济带一体化战略对“五位一体”高质量发展的影响效应和影响机制。研究表明:长江经济带战略的实施整体上对长江经济带的“五位一体”高质量发展具有促进作用;区域异质性分析显示,其对中西部具有显著的促进作用,且对中部的正向效应大于西部,而对于东部地区的促进作用并不显著;机制分析显示,长江经济带战略能够通过促进投资需求、产业结构优化以及绿色技术创新发展间接推动沿线省市的“五位一体”高质量发展。
