Electrically conducting fabrics used as flexible sensors can be produced by vacuumed vapor deposition.The research of what impacts the wide and reliable application of the flexible sensors shows that the stability of ...Electrically conducting fabrics used as flexible sensors can be produced by vacuumed vapor deposition.The research of what impacts the wide and reliable application of the flexible sensors shows that the stability of flexible sensors is one of the critical issues.The electrical performance of weft knitted fabrics in course and wale direction does not show significant differences under different ambient conditions,which include time,temperature,and relative humidity.Tests of stimuli responding sensitivity of conductive fabrics indicate that the sensitivity keeps at a constant level and the average sensitivity is stable over 38 days.展开更多
针对大规模风电场接入给电力系统安全稳定分析过程带来的方程高维性、计算效率低问题,提出了一种基于模型-数据混合驱动的风电场暂态过程等值方法。对整个风电场进行两阶段聚合,最终将含有多台风机的风电场等值为单台风机模型。第一阶...针对大规模风电场接入给电力系统安全稳定分析过程带来的方程高维性、计算效率低问题,提出了一种基于模型-数据混合驱动的风电场暂态过程等值方法。对整个风电场进行两阶段聚合,最终将含有多台风机的风电场等值为单台风机模型。第一阶段等值过程中基于物理模型驱动思想,通过获取不同风速下风机并网点有功暂态响应特性及出力特性,采用K-means方法将所有风机聚合为四台等效风机。第二阶段基于数据驱动策略,通过所建立风电场并网点有功偏差最小的多时段优化模型并结合长短期记忆网络(long short term memory,LSTM)训练,将四台等效风机聚合为单台风机模型,实现了整个风电场的暂态过程等值聚合。通过算例验证了所提等值方法能够有效地反映风电场的暂态过程特性,为电力系统安全稳定分析模型降维提供了一种实用化解决方案。展开更多
Peptides/proteins aggregation can give rise to pathological conditions of many human diseases.Small partially ordered oligomers formed in the early stage of aggregation,rather than mature fibrils,are thought to be the...Peptides/proteins aggregation can give rise to pathological conditions of many human diseases.Small partially ordered oligomers formed in the early stage of aggregation,rather than mature fibrils,are thought to be the main toxicity agent for the living cell.Thus,understanding the pathway and the underlying physical mechanism in the early stage of aggregation is very important for prevention and treatment of these protein functional diseases.Herein we use all-atom molecular dynamics simulations to study the aggregation of four NFGAIL hexapeptides(NFGAIL peptide is a core segment of human islet amyloid polypeptide and exhibits similar aggregation kinetics as the full-length polypeptide).We observe that the peptide monomers in water mainly adopt non-structural coil configurations;the four peptides which are randomly placed in water aggregate spontaneously to partially ordered oligomer(β-sheets)through dimerization or trimerization,with the dimerization predominated.Both parallel and anti-parallelβ-sheets are observed.The hydrophobic interactions drive the initial peptides associations,and the subsequent conformational fluctuations promote the formation of more hydrogen bonds between the dangling hydrogen sites in the main chains of peptides.展开更多
The site order parameter (SOP) has been adopted to analyze various orders of structure formation and distribution during the crystallization of a polyethylene globule simulated by molecular dynamics. The SOP not only ...The site order parameter (SOP) has been adopted to analyze various orders of structure formation and distribution during the crystallization of a polyethylene globule simulated by molecular dynamics. The SOP not only identifies different orders among the structures but also different phases. The results showed that intermediate structures with medium order exist unevenly in the early stage of nucleation, which differs from traditional models. We found that the nucleation relies on crystallinity fluctuations with increasing amplitude, and a baby nucleus with different shape and increasing size suddenly appears in the fluctuations. Once its size is large enough, the baby nucleus becomes the nucleus. In the growth stage, a number of lamellar mergences were observed and their selective behaviors were related to the orientation differences between the lamellae to be merged. The SOP distribution of all atoms in the system during crystallization had two peaks: one for the amorphous phase and the other for the crystalline phase. The intermediate structures with medium orders are located between the two peaks as an order promotion pathway. The data show that the medium order structure fluctuates at the growth front and is not always available, and that the medium order structure existing at the front is not always good for development. It is possibly caused by chain entanglement. Structure fluctuation at the growth front enables the system showing thousands of the most probable configurations to approach the precursor. The growth front is thus active for a while and inactive at other times.展开更多
文摘Electrically conducting fabrics used as flexible sensors can be produced by vacuumed vapor deposition.The research of what impacts the wide and reliable application of the flexible sensors shows that the stability of flexible sensors is one of the critical issues.The electrical performance of weft knitted fabrics in course and wale direction does not show significant differences under different ambient conditions,which include time,temperature,and relative humidity.Tests of stimuli responding sensitivity of conductive fabrics indicate that the sensitivity keeps at a constant level and the average sensitivity is stable over 38 days.
文摘针对大规模风电场接入给电力系统安全稳定分析过程带来的方程高维性、计算效率低问题,提出了一种基于模型-数据混合驱动的风电场暂态过程等值方法。对整个风电场进行两阶段聚合,最终将含有多台风机的风电场等值为单台风机模型。第一阶段等值过程中基于物理模型驱动思想,通过获取不同风速下风机并网点有功暂态响应特性及出力特性,采用K-means方法将所有风机聚合为四台等效风机。第二阶段基于数据驱动策略,通过所建立风电场并网点有功偏差最小的多时段优化模型并结合长短期记忆网络(long short term memory,LSTM)训练,将四台等效风机聚合为单台风机模型,实现了整个风电场的暂态过程等值聚合。通过算例验证了所提等值方法能够有效地反映风电场的暂态过程特性,为电力系统安全稳定分析模型降维提供了一种实用化解决方案。
基金Supported by the National Natural Science Foundation of China under Grant Nos.30870593 and 11204269the China Postdoctoral Science Foundation under Grant No.2012M511351+2 种基金Zhejiang Provincial Natural Science Foundation of China under Grant No.LY12A04007the Fundamental Research Funds for the Central Universitiesthe KYLIN-I Supercomputer in Institute for Fusion Theory and Simulation,Zhejiang University
文摘Peptides/proteins aggregation can give rise to pathological conditions of many human diseases.Small partially ordered oligomers formed in the early stage of aggregation,rather than mature fibrils,are thought to be the main toxicity agent for the living cell.Thus,understanding the pathway and the underlying physical mechanism in the early stage of aggregation is very important for prevention and treatment of these protein functional diseases.Herein we use all-atom molecular dynamics simulations to study the aggregation of four NFGAIL hexapeptides(NFGAIL peptide is a core segment of human islet amyloid polypeptide and exhibits similar aggregation kinetics as the full-length polypeptide).We observe that the peptide monomers in water mainly adopt non-structural coil configurations;the four peptides which are randomly placed in water aggregate spontaneously to partially ordered oligomer(β-sheets)through dimerization or trimerization,with the dimerization predominated.Both parallel and anti-parallelβ-sheets are observed.The hydrophobic interactions drive the initial peptides associations,and the subsequent conformational fluctuations promote the formation of more hydrogen bonds between the dangling hydrogen sites in the main chains of peptides.
文摘The site order parameter (SOP) has been adopted to analyze various orders of structure formation and distribution during the crystallization of a polyethylene globule simulated by molecular dynamics. The SOP not only identifies different orders among the structures but also different phases. The results showed that intermediate structures with medium order exist unevenly in the early stage of nucleation, which differs from traditional models. We found that the nucleation relies on crystallinity fluctuations with increasing amplitude, and a baby nucleus with different shape and increasing size suddenly appears in the fluctuations. Once its size is large enough, the baby nucleus becomes the nucleus. In the growth stage, a number of lamellar mergences were observed and their selective behaviors were related to the orientation differences between the lamellae to be merged. The SOP distribution of all atoms in the system during crystallization had two peaks: one for the amorphous phase and the other for the crystalline phase. The intermediate structures with medium orders are located between the two peaks as an order promotion pathway. The data show that the medium order structure fluctuates at the growth front and is not always available, and that the medium order structure existing at the front is not always good for development. It is possibly caused by chain entanglement. Structure fluctuation at the growth front enables the system showing thousands of the most probable configurations to approach the precursor. The growth front is thus active for a while and inactive at other times.
