Regard to the real-time dynamic digital twin modelling problem of a new-type distribution network that includes distributed resources such as distributed photovoltaic,energy storage,charging pile,and electric vehicle,...Regard to the real-time dynamic digital twin modelling problem of a new-type distribution network that includes distributed resources such as distributed photovoltaic,energy storage,charging pile,and electric vehicle,a new-type distribution network digital twin topology modeling method based on Common Information Model(CIM)specifications and spectral clustering is proposed.Firstly,according to the specifications of the CIM standard,the digital twin topology models of distributed resources are extended and established.Secondly,based on the digital twin topology models of distributed resources,a digital twin aggregation modelling method for new-type distribution network is proposed based on spectral clustering.Furthermore,an online linked update strategy for the digital twin model of new-type distribution network that integrates real-time topology states is proposed.Finally,a case study is conducted on a distribution network in a certain demonstration area in China,and the results verify the practicability and effectiveness of the method proposed in this paper.This lays the foundation for the application of electrical network twin analysis,such as power flow calculation,optimal power flow,economic dispatch,and safety check,in a new-type distribution network that includes diversified distributed resources.展开更多
目的:探讨带状疱疹后神经痛(postherpetic neuralgia,PHN)病人共病抑郁障碍的影响因素,并构建预测模型。方法:回顾性分析2021年3月至2024年12月期间福建医科大学附属第一医院疼痛科收治的282例PHN病人的临床资料,根据病人是否共病抑郁...目的:探讨带状疱疹后神经痛(postherpetic neuralgia,PHN)病人共病抑郁障碍的影响因素,并构建预测模型。方法:回顾性分析2021年3月至2024年12月期间福建医科大学附属第一医院疼痛科收治的282例PHN病人的临床资料,根据病人是否共病抑郁障碍分为PHN共病抑郁障碍组(n=94)和单纯PHN组(n=188),通过Logistic回归分析筛选其影响因素,构建列线图预测模型并综合评价模型性能。结果:多因素Logistic回归分析显示PHN病程、恶性肿瘤史、数字分级评分法(numerical rating scale,NRS)评分、受教育程度、社会支持评定量表(social support rating scale,SSRS)评分是PHN共病抑郁障碍的影响因素。通过Bootstrap验证法进行内部验证后,列线图预测PHN共病抑郁障碍的曲线下面积(area under the curve,AUC)值为0.970(95%CI:0.941-0.987),灵敏度0.890,特异度0.941,显示模型区分能力可靠;Hosmer-Lemeshow检验结果显示X 2=5.293,P=0.726,Brier评分为0.049,校准曲线显示模型具有较好的校准度及预测一致性;临床决策曲线分析(decision curve analysis,DCA)显示模型具有良好的临床适用性。结论:PHN病程、恶性肿瘤史、NRS评分是PHN共病抑郁障碍的独立危险因素,受教育程度、SSRS评分是其独立保护因素,据此构建的列线图模型具有可靠的临床预测价值。展开更多
以MQU-F(Magnequench ultra-fine)磁粉为原料,经热压制+模压成形得到模压成形Nd-Fe-B磁体,随后以Pr_(70)Cu_(30)共晶合金为扩散源,在不同压力下(0、10、20 k Pa)对磁体进行压力辅助晶界扩散处理。研究发现,晶界扩散后,钕铁硼磁体的矫顽...以MQU-F(Magnequench ultra-fine)磁粉为原料,经热压制+模压成形得到模压成形Nd-Fe-B磁体,随后以Pr_(70)Cu_(30)共晶合金为扩散源,在不同压力下(0、10、20 k Pa)对磁体进行压力辅助晶界扩散处理。研究发现,晶界扩散后,钕铁硼磁体的矫顽力显著提升,但剩磁会降低。在微观结构方面,富钕相体积分数增加且在界面局部富集,于主相晶粒边界形成隔离层,增强富钕相钉扎作用,提升矫顽力;但富钕相过量致使主相晶粒取向一致性下降,导致剩磁衰减。此外,辅助压力增加时,矫顽力不断提升,剩磁则不断衰减。压力能够促进Pr、Cu元素渗透,优化非铁磁性晶间相网络形成,但也会引起主相晶粒局部取向杂乱。在微观结构上,压力使富钕相分布更连续,晶粒细化,优化微观结构均匀性。压力增大还能促进熔融扩散源向磁体心部渗透,Pr、Cu元素主要富集在距表面1.5 mm范围内,其含量随压力增加而增加,且增加压力提升了元素沿晶界网络的扩散效率,元素含量随深度分布曲线斜率变大。展开更多
特定堆型的一回路冷却剂中通过加入氨调控pH,并利用其辐解产物抑制氧化性物质的浓度,从而维持冷却剂的还原性状态。在此过程中,氨浓度与pH调控产生显著的联动影响,需要建立可模拟不同控制策略下水化学行为的模型,实现pH和溶解氢浓度控...特定堆型的一回路冷却剂中通过加入氨调控pH,并利用其辐解产物抑制氧化性物质的浓度,从而维持冷却剂的还原性状态。在此过程中,氨浓度与pH调控产生显著的联动影响,需要建立可模拟不同控制策略下水化学行为的模型,实现pH和溶解氢浓度控制。本工作基于RETA反应堆系统分析程序,开发了一个适用于压水堆型冷却剂辐解产物输运的模型,模型预测NH_(3)和H_(2)浓度与实验结果的均方误差分别为1.79×10^(−8)和5.69×10^(−8)。以KLT-40S堆型为对象,构建并对比分析了三种加氨调控策略:初始弥散加氨、源恒速加氨及基于除氢优化的源恒速加氨。在模拟过程中,设置了冷却剂初始参数与辐射场条件,逐步调整加氨速率与除氢时机。每种策略均模拟至系统达到准稳态(1.6×10^(4) s),以评估其对pH和溶解氢浓度的调控效果。结果显示,初始氨弥散策略简单直接,可维持体系的还原性但对冷却剂pH调控的时间小于5 h;源恒速加氨可长时间有效调节冷却剂pH,但会带来溶解氢浓度过高的问题,需匹配相应的除氢方案。采用基于除氢优化的源恒速加氨策略,能够同时满足稳定控制pH和溶解氢浓度的要求,加氨速率为1.64 g·s^(−1),加氨开始1200 s后开启除氢装置,除氢速率0.014 g·s^(−1),化学状态稳定后冷却剂的pH为6.9,溶解氢浓度为30~35 mL·kg−(1)(Standard Temperature and Pressure,STP)。本工作有望为新堆型研发和水化学控制策略的优化提供参考。展开更多
The strength of traditional commercially pure titanium(CP-Ti) alloys often fails to meet the demand of structural materials. In order to enhance their mechanical properties, the cold-rolled CP-Ti alloys were annealed ...The strength of traditional commercially pure titanium(CP-Ti) alloys often fails to meet the demand of structural materials. In order to enhance their mechanical properties, the cold-rolled CP-Ti alloys were annealed at different temperatures, and the recrystallization behavior and texture evolution were investigated. It was found that the bimodal microstructure(equiaxed and elongated grains) was formed after partial recrystallization, and the corresponding sample exhibited an excellent combination of ultimate tensile strength(702 MPa) and total elongation(36.4%). The recrystallization nucleation of CP-Ti sheets occurred preferentially in the high strain and the high-angle grain boundaries(HAGBs) regions. Meanwhile, the internal misorientations of the deformed heterogeneous grains increased and transformed into HAGBs, which further promoted the recrystallization nucleation. The main recrystallization texture was basal TD-split texture transformed from cold-rolled basal RD-split texture, and the oriented nucleation played a dominated role during recrystallization.展开更多
基金Supported by Science and Technology Project of State Grid Corporation of China(5108-202218280A-2-396-XG).
文摘Regard to the real-time dynamic digital twin modelling problem of a new-type distribution network that includes distributed resources such as distributed photovoltaic,energy storage,charging pile,and electric vehicle,a new-type distribution network digital twin topology modeling method based on Common Information Model(CIM)specifications and spectral clustering is proposed.Firstly,according to the specifications of the CIM standard,the digital twin topology models of distributed resources are extended and established.Secondly,based on the digital twin topology models of distributed resources,a digital twin aggregation modelling method for new-type distribution network is proposed based on spectral clustering.Furthermore,an online linked update strategy for the digital twin model of new-type distribution network that integrates real-time topology states is proposed.Finally,a case study is conducted on a distribution network in a certain demonstration area in China,and the results verify the practicability and effectiveness of the method proposed in this paper.This lays the foundation for the application of electrical network twin analysis,such as power flow calculation,optimal power flow,economic dispatch,and safety check,in a new-type distribution network that includes diversified distributed resources.
文摘目的:探讨带状疱疹后神经痛(postherpetic neuralgia,PHN)病人共病抑郁障碍的影响因素,并构建预测模型。方法:回顾性分析2021年3月至2024年12月期间福建医科大学附属第一医院疼痛科收治的282例PHN病人的临床资料,根据病人是否共病抑郁障碍分为PHN共病抑郁障碍组(n=94)和单纯PHN组(n=188),通过Logistic回归分析筛选其影响因素,构建列线图预测模型并综合评价模型性能。结果:多因素Logistic回归分析显示PHN病程、恶性肿瘤史、数字分级评分法(numerical rating scale,NRS)评分、受教育程度、社会支持评定量表(social support rating scale,SSRS)评分是PHN共病抑郁障碍的影响因素。通过Bootstrap验证法进行内部验证后,列线图预测PHN共病抑郁障碍的曲线下面积(area under the curve,AUC)值为0.970(95%CI:0.941-0.987),灵敏度0.890,特异度0.941,显示模型区分能力可靠;Hosmer-Lemeshow检验结果显示X 2=5.293,P=0.726,Brier评分为0.049,校准曲线显示模型具有较好的校准度及预测一致性;临床决策曲线分析(decision curve analysis,DCA)显示模型具有良好的临床适用性。结论:PHN病程、恶性肿瘤史、NRS评分是PHN共病抑郁障碍的独立危险因素,受教育程度、SSRS评分是其独立保护因素,据此构建的列线图模型具有可靠的临床预测价值。
文摘以MQU-F(Magnequench ultra-fine)磁粉为原料,经热压制+模压成形得到模压成形Nd-Fe-B磁体,随后以Pr_(70)Cu_(30)共晶合金为扩散源,在不同压力下(0、10、20 k Pa)对磁体进行压力辅助晶界扩散处理。研究发现,晶界扩散后,钕铁硼磁体的矫顽力显著提升,但剩磁会降低。在微观结构方面,富钕相体积分数增加且在界面局部富集,于主相晶粒边界形成隔离层,增强富钕相钉扎作用,提升矫顽力;但富钕相过量致使主相晶粒取向一致性下降,导致剩磁衰减。此外,辅助压力增加时,矫顽力不断提升,剩磁则不断衰减。压力能够促进Pr、Cu元素渗透,优化非铁磁性晶间相网络形成,但也会引起主相晶粒局部取向杂乱。在微观结构上,压力使富钕相分布更连续,晶粒细化,优化微观结构均匀性。压力增大还能促进熔融扩散源向磁体心部渗透,Pr、Cu元素主要富集在距表面1.5 mm范围内,其含量随压力增加而增加,且增加压力提升了元素沿晶界网络的扩散效率,元素含量随深度分布曲线斜率变大。
文摘特定堆型的一回路冷却剂中通过加入氨调控pH,并利用其辐解产物抑制氧化性物质的浓度,从而维持冷却剂的还原性状态。在此过程中,氨浓度与pH调控产生显著的联动影响,需要建立可模拟不同控制策略下水化学行为的模型,实现pH和溶解氢浓度控制。本工作基于RETA反应堆系统分析程序,开发了一个适用于压水堆型冷却剂辐解产物输运的模型,模型预测NH_(3)和H_(2)浓度与实验结果的均方误差分别为1.79×10^(−8)和5.69×10^(−8)。以KLT-40S堆型为对象,构建并对比分析了三种加氨调控策略:初始弥散加氨、源恒速加氨及基于除氢优化的源恒速加氨。在模拟过程中,设置了冷却剂初始参数与辐射场条件,逐步调整加氨速率与除氢时机。每种策略均模拟至系统达到准稳态(1.6×10^(4) s),以评估其对pH和溶解氢浓度的调控效果。结果显示,初始氨弥散策略简单直接,可维持体系的还原性但对冷却剂pH调控的时间小于5 h;源恒速加氨可长时间有效调节冷却剂pH,但会带来溶解氢浓度过高的问题,需匹配相应的除氢方案。采用基于除氢优化的源恒速加氨策略,能够同时满足稳定控制pH和溶解氢浓度的要求,加氨速率为1.64 g·s^(−1),加氨开始1200 s后开启除氢装置,除氢速率0.014 g·s^(−1),化学状态稳定后冷却剂的pH为6.9,溶解氢浓度为30~35 mL·kg−(1)(Standard Temperature and Pressure,STP)。本工作有望为新堆型研发和水化学控制策略的优化提供参考。
基金financially supported by the National Natural Science Foundation of China (No.52104372)the Fundamental Research Funds for the Central Universities,China (No.N2107001)the China Postdoctoral Science Foundation (No.2019M651129)。
文摘The strength of traditional commercially pure titanium(CP-Ti) alloys often fails to meet the demand of structural materials. In order to enhance their mechanical properties, the cold-rolled CP-Ti alloys were annealed at different temperatures, and the recrystallization behavior and texture evolution were investigated. It was found that the bimodal microstructure(equiaxed and elongated grains) was formed after partial recrystallization, and the corresponding sample exhibited an excellent combination of ultimate tensile strength(702 MPa) and total elongation(36.4%). The recrystallization nucleation of CP-Ti sheets occurred preferentially in the high strain and the high-angle grain boundaries(HAGBs) regions. Meanwhile, the internal misorientations of the deformed heterogeneous grains increased and transformed into HAGBs, which further promoted the recrystallization nucleation. The main recrystallization texture was basal TD-split texture transformed from cold-rolled basal RD-split texture, and the oriented nucleation played a dominated role during recrystallization.
