Differences between Fallers by Tripping and Nonfallers in the OSFS Test

This study evaluates the effects of a fall experience caused by tripping during the repetitive stepping movements over an obstacle [obstacle-single leg forward step (OSFS) test]. The study included 147 participants who were divided into 2 groups: 25 fallers caused by tripping and 122 nonfallers. The subjects were asked to step forward over a 10-cm-high obstacle with 1 leg and then return to their original position, as quickly as possible, and this test was repeated for 5 times. The OSFS test was evaluated in 2 phases: the OSFS-F phase, wherein the participants stepped forward on one leg, and the OSFS-R phase, wherein they returned to their original position. Significant differences were observed in both phases of the OSFS test between the two groups, and the fallers by tripping were significantly inferior to the nonfallers. The area under the curve [AUC;area under the receiver operating characteristic (ROC) curve] was more than 0.63 for all the parameters, which was statistically significant. In conclusion, the fallers by tripping were inferior to the nonfallers in the obstacle step movement.

The effects of fall experience by tripping on the movement of stepping over an obstacle

This study examines the effects of fall experience caused by tripping on the movement of stepping over an obstacle. The participants were divided into 3 groups (26 fallers caused by tripping, 24 fallers caused by other causes, and 145 non-fallers). Participants stepped forward over a 10 cm high obstacle with one leg, and then returned to their original position five times as quickly as possible. The OSFS (obstacle single leg forward step) test was measured in the following 2 phases: the OSFS-F phase, in which participants stepped out on one leg, and the OSFS-R phase, in which they returned it. Significant differences among the three groups were found in all parameters, and the fallers by tripping were significantly inferior to the non-fallers. There were no significant differences between the fallers by other reasons and the non-fallers in all parameters. The fallers by tripping were slower in the obstacle step movement than the non-fallers.

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7月29日,旧金山度假租赁搜索引擎Tripping.com获得1600万美元B轮投资。本轮融资由纽约早期投资机构Steadfast Venture Capital领投,前Expedia CEO Erik Blachford、7 Seas Venture Partners、Enspire Capital、Azure Capital、

Intelligent Predetermination of Generator Tripping Scheme: Knowledge Fusion-based Deep Reinforcement Learning Framework

Generator tripping scheme(GTS)is the most commonly used scheme to prevent power systems from losing safety and stability.Usually,GTS is composed of offline predetermination and real-time scenario match.However,it is extremely time-consuming and labor-intensive for manual predetermination for a large-scale modern power system.To improve efficiency of predetermination,this paper proposes a framework of knowledge fusion-based deep reinforcement learning(KF-DRL)for intelligent predetermination of GTS.First,the Markov Decision Process(MDP)for GTS problem is formulated based on transient instability events.Then,linear action space is developed to reduce dimensionality of action space for multiple controllable generators.Especially,KF-DRL leverages domain knowledge about GTS to mask invalid actions during the decision-making process.This can enhance the efficiency and learning process.Moreover,the graph convolutional network(GCN)is introduced to the policy network for enhanced learning ability.Numerical simulation results obtained on New England power system demonstrate superiority of the proposed KF-DRL framework for GTS over the purely data-driven DRL method.

An Optimal Over-frequency Generator Tripping Strategy for Regional Power Grid with High Penetration Level of Renewable Energy

This paper proposes an optimal over-frequency generator tripping strategy aiming at implementing the least amount of generator tripping for the regional power grid with high penetration level of wind/photovoltaic(PV),to handle the over-frequency problem in the sending-end power grid under large disturbances.A steady-state frequency abnormal index is defined to measure the degrees of generator over-tripping and under-tripping,and a transient frequency abnormal index is presented to assess the system abnormal frequency effect during the transient process,which reflects the frequency security margin during the generator tripping process.The scenariobased analysis method combined with the non-parametric kernel density estimation method is applied to model the uncertainty of the outgoing power caused by the stochastic fluctuations of wind/PV power and loads.Furthermore,an improved fireworks algorithm is utilized for the solution of the proposed optimization model.Finally,the simulations are performed on a real-sized regional power grid in Southern China to verify the effectiveness and adaptability of the proposed model and method.

Differential Power Based Selective Phase Tripping for Fault-resilient Microgrid

Modern fault-resilient microgrids(MGs)require the operation of healthy phases during unbalanced short-circuits to improve the system reliability.This study proposes a differential power based selective phase tripping scheme for MGs consisting of synchronous and inverter-interfaced distributed generators(DGs).First,the differential power is computed using the line-end superimposed voltage and current signals.Subsequently,to make the scheme threshold-free,a power coefficient index is derived and used for identifying faulted phases in an MG.The protection scheme is tested on a standard MG operating in either grid-connected or islanding mode,which is simulated using PSCAD/EMTDC.The efficacy of the scheme is also assessed on the OPAL-RT manufactured real-time digital simulation(RTDS)platform.Further,the performance of the proposed protection scheme is compared with a few existing methods.The results show that the selective tripping of faulted phases in MGs can be achieved quickly and securely using the proposed scheme.

INVESTIGATION OF THE MEAN-FLOW SCALING AND TRIPPING EFFECT ON FULLY DEVELOPED TURBULENT PIPE FLOW

Fully developed turbulence measurements in pipe flow were made in theReynolds number range from 10 X 10~3 to 350 X 10~3 with hot-wire anemometer and a Pilot tube.Comparisons were made with the experimental results of previous researchers. The mean velocityprofile and the turbulent intensity in the experiments indicate that for the mean velocity profile,in the fully developed turbulent pipe flow, von Karman's constant κ is a function of the Reynoldsnumber, i. e. κ increases slowly with the Reynolds number. For turbulent pipe flow, the outer limitdepends on whether the Kdrmdn number R^+ is greater or less than 850 in the centerline velocityprofile: a log law exists for 850 < R^+< 1750 in the experiment, and von Karman' s constant κ isshown to be 0. 408. Under the effects of the test trip at the inlet, fully developed turbulence wasobtained in pipe flow at lower Reynolds number when the entrance length (x/D) was larger than 40. Inthe experiment it was also found that turbulence quantities in pipe flow remain independent of theupstream conditions when the trip blockage ratio is higher than 20%, and the comparison with channelwater flow was also performed.

药品数据专有权国际立法溯源与中国制度安排

药品上市审批对于药品安全有效性数据的专门审查要求,造就了涉及药品数据的独特知识产权保护机制。基于药品数据获取的高昂投入及其对于药品仿制与后续创新的重要价值,美欧发达国家在世界范围内率先建立了药品数据保护机制,其逐渐成为一项国际性的法律规则。无论是美欧发达国家的立法,还是相关国际法律规则,对于药品数据的知识产权保护都呈现从商业秘密模式向专有权机制转变的立法格局。产业利益驱动无疑是其中的一个重要诱因,但归根结底是源自药品数据专有权有效兼顾原研发药企经济利益与社会公众健康权益的制度优势。鉴于此,在药品数据专有权保护的国际趋势下,我国应从本土药品产业激励创新与规范仿制的基本诉求出发,以必要的内部限制与外部监管明确药品数据专有权的法律边界,并通过药品数据动态化公示平台的设置与药品数据付费使用模式的创设,建构起与药品专利制度有机衔接的数据专有权保护机制。

TRIP980钢的组织性能调控与动态本构模型

设计了一种相变诱导塑性(TRIP)钢,研究了贝氏体等温温度对力学性能和微观组织的影响。针对最优工艺,研究了10^(-4)~10^(3) s^(-1)应变速率范围内的动态力学性能,构建并修正了动态本构数学模型。结果表明:当贝氏体等温温度为380℃时,实验钢具有最优的静态力学性能(应变速率10^(-3)s^(-1)),屈服强度达到705 MPa,抗拉强度达到1005 MPa,伸长率为16%,强塑积达到了1.6 GPa·%。应变速率的变化对实验钢的硬化行为和TRIP效应的发生有明显的影响。当应变速率达到10^(3) s^(-1)时,屈服强度和抗拉强度分别达到了815和1145 MPa,分别提高了12.4%和13.9%。经A4系数修正后的动态本构数学模型表明,R值和eAARE的平均值分别达到0.9895和27.5%,具有较精确的预测精度。

热处理工艺对吉帕级Q & P钢组织和力学性能的影响

采用光学显微镜、扫描电子显微镜、透射电子显微镜、X射线衍射仪及拉伸试验机等,研究了热处理工艺对冷轧态和预淬火态Q&P钢显微组织和力学性能的影响。结果表明:冷轧态试验钢组织呈等轴状,预淬火态试验钢组织具有层片状特征;对于冷轧态试样,两相区保温温度、淬火温度和配分温度均会对试验钢的力学性能产生明显影响,残留奥氏体的稳定性参数R值与强塑积的变化趋势一致,表明在拉伸载荷作用下残留奥氏体发挥相变诱发塑性(transformation induced plasticity, TRIP)效应是试验钢强塑化的主要原因;对于预淬火态试样,层片状组织有助于残留奥氏体更好地增强TRIP效应,并阻碍裂纹扩展,从而进一步提高其强塑积。

Dual nanoprecipitation and nanoscale chemical heterogeneity in a secondary hardening steel for ultrahigh strength and large uniform elongation

Nanoprecipitates and nanoscale retained austenite(RA)with suitable stability play crucial roles in deter-mining the yield strength(YS)and ductility of ultrahigh strength steels(UHSSs).However,owing to the kinetics incompatibility between nanoprecipitation and austenite reversion,it is highly challenging to si-multaneously introduce high-density nanoprecipitates and optimized RA in UHSSs.In this work,through the combination of austenite reversion treatment(ART)and subsequent flash austenitizing(FA),nanoscale chemical heterogeneity was successfully introduced into a low-cost UHSS prior to the aging process.This chemical heterogeneity involved the enrichment of Mn and Ni in the austenite phase.The resulting UHSS exhibited dual-nanoprecipitation of Ni(Al,Mn)and(Mo,Cr)_(2)C and nanoscale austenite stabilized via Mn and Ni enrichment.The hard martensitic matrix strengthened by high-density dual-nanoprecipitates con-strains the plastic deformation of soft RA with a relatively low fraction of-15%,and the presence of relatively stable nanoscale RA with adequate Mn and Ni enrichment leads to a marginal loss in YS but keeps a persistent transformation-induced plasticity(TRIP)effect.As a result,the newly-developed UHSS exhibits an ultrahigh YS of-1.7 GPa,an ultimate tensile strength(UTS)of-1.8 GPa,a large uniform elongation(UE)of-8.5%,and a total elongation(TE)of-13%.The strategy of presetting chemical heterogeneity to introduce proper metastable phases before aging can be extended to other UHSSs and precipitation-hardened alloys.

TRIP13通过同源重组通路提高肺腺癌细胞的放射抗性

背景与目的放疗是非小细胞肺癌(non-small cell lung cancer,NSCLC)最常用的治疗手段之一。然而,一部分肿瘤细胞对放射线的不敏感是放疗疗效差、患者预后不良的重要原因之一,探究放射抵抗背后的深层机制是解决这一临床难题的关键。本研究旨在寻找与肺腺癌(lungadenocarcinoma,LUAD)放射抵抗相关的分子,初步经数据库筛选锁定甲状腺素受体结合因子13(thyroid hormone receptor interactor 13,TRIP13)为主要研究对象,并探索TRIP13是否与LUAD的放射抵抗有关及具体机制,以期为临床接受放疗的LUAD患者的联合治疗提供理论依据和潜在靶点。方法选取基因表达综合数据库(Gene Expression Omnibus,GEO)中的GSE18842、GSE19188和GSE33532共3个数据集,借助R 4.1.3软件分别筛选3个数据集中差异表达的基因(|logFC|>1.5,P<0.05),之后使用Venn diagram找出在3个数据集中共有的差异表达基因。随后,借助STRING在线工具和Cytoscape软件,对筛选出来的差异基因进行蛋白质相互作用分析和模块分析,借助Kaplan-Meier Plotter数据库对各基因进行生存预后分析,并确定TRIP13基因作为后续主要研究分子。随后,采用亚致死性剂量照射法对人LUAD细胞系H292进行多次X射线照射,以构建具有放射抗性的细胞系H292DR。采用细胞计数试剂盒-8(cell counting kit-8,CCK-8)实验和克隆形成实验验证H292DR细胞的放射抗性能力。Western blot检测H292细胞和H292DR细胞中TRIP13蛋白的表达水平。使用小干扰RNA(small interfering RNA,siRNA)沉默H292DR细胞中TRIP 13蛋白的表达并进行Western blot检测。观察TRIP13沉默后H292DR细胞的克隆形成能力和迁移能力,随后检测共济失调-毛细血管扩张突变(ataxia telangiectasia mutated,ATM)蛋白等与同源重组密切相关的蛋白的表达水平变化。结果经多个GEO数据集筛选、外部数据集的验证以及生存分析发现,TRIP13在LUAD中高表达,并与接受过放疗的LUAD患者的不良预后有关;并且,TRIP13基因富集分析(gene set enrichment analysis,GSEA)的结果提示,TRIP13可能通过促进放疗后的同源重组修复而与LUAD放射抵抗有密切关联。经实验检测发现,TRIP13的表达在H292DR中上调,而沉默TRIP13后能够增加H292DR细胞对放射线的敏感性。结论TRIP13与接受放疗后的LUAD患者的预后不良有关,可能是通过促进同源重组修复途径来介导LUAD细胞对放射线的抵抗。

热处理对热轧Fe-0.4C-10Mn-1.8Al-0.6V钢组织及力学性能的影响

研究了新型热轧Fe-0.4C-10Mn-1.8Al-0.6V中锰钢的组织和力学性能。结果表明,随着退火时间从30 min增加到60 min,由于稳定性下降导致残余奥氏体体积分数降低,板条状马氏体逐渐转变为针状马氏体。由于变形阶段不连续TRIP效应的发生,拉伸曲线呈锯齿状。随着退火时间的延长,实验钢的屈服强度、抗拉强度及总伸长率均降低。实验钢在800℃进行30 min退火后具有良好的力学性能,屈服强度为670 MPa,抗拉强度为1230 MPa,总伸长率为18.3%。

固溶处理对S32001双相不锈钢力学性能和点蚀敏感性影响

目的 研究固溶工艺对S32001经济型双相不锈钢的微观组织、拉伸力学性能和点蚀敏感性的影响作用。方法 通过光学显微镜、扫描电镜及EDS等方法,研究S32001双相不锈钢中的双相组织、固溶元素含量及腐蚀形貌。通过万能试验机研究拉伸力学性能随固溶工艺的变化规律,采用电化学工作站研究临界点蚀电位和临界点蚀温度等与固溶工艺的变化关系。结果 当固溶温度在1 000~1 200℃时,随着固溶温度的升高,铁素体相比例逐渐增加,而奥氏体相比例逐渐减小。屈服强度变化很小,而抗拉强度、断裂伸长率及强塑积等性能呈现逐渐减小的趋势。临界点蚀电位和临界点蚀温度等结果均表明,随着固溶温度的升高,不锈钢的点蚀敏感性呈现先减小、后增大的趋势。结论 S32001双相钢在不同固溶温度下的力学性能差异应主要与应变硬化行为有关,这主要与较高固溶温度下相变诱导塑性(TRIP效应)被抑制有关。当固溶温度为1 100℃时,奥氏体铁素体两相的体积比约1︰1,此时奥氏体相和铁素体相的耐点蚀当量(PREN值)最为接近,合金的点蚀敏感性最低,即抗点蚀能力最强。

中锰Q&P钢微观组织演变和力学性能分析

探究了在不同退火温度下,中锰Q&P钢微观组织演变和力学性能的特征。深入分析了残余奥氏体含量及稳定性、残余奥氏体的形貌特征,讨论了其加工硬化行为和TRIP效应。研究发现,退火温度的改变能显著影响残余奥氏体含量及微观形貌特征,位错密度能显著改善残余奥氏体机械稳定性,不同形态的奥氏体结构的交错分布更有利于性能的改善。当退火温度达到700℃时,抗拉强度为1290 MPa,延伸率为34.08%,强塑积可达43.96GPa·%。

TRIP13促进子宫内膜癌增殖、迁移和侵袭的影响及作用机制

目的:探讨甲状腺激素受体因子13(Thyroid hormone receptor interactor 13,TRIP13)对子宫内膜癌(Endometrial carcinoma,EC)增殖、迁移和侵袭的影响及调控机制。方法:分析TRIP13在子宫内膜癌中的表达模式;通过慢病毒敲减和质粒过表达调控子宫内膜癌细胞中TRIP13的表达量;通过CCK-8、Transwell迁移及侵袭实验观察TRIP13对子宫内膜癌细胞增殖、迁移及侵袭能力的影响;通过Western blot技术检测TRIP13表达水平的变化,并研究其对PI3K/Akt信号通路蛋白的影响。结果:癌症基因组图谱(The Cancer Genome Atlas,TCGA)分析发现,子宫内膜癌组织中TRIP13的表达水平显著高于正常子宫内膜组织(P<0.05);TRIP13的高表达与子宫内膜癌患者的低生存率呈显著正相关(P<0.05)。TRIP13过表达可促进子宫内膜癌细胞的增殖、迁移及侵袭能力(P<0.05),并上调p-PI3K、p-Akt的表达(P<0.05),而下调TRIP13后则可逆转上述结果。结论:TRIP13通过调控PI3K/Akt信号通路促进子宫内膜癌细胞的增殖、迁移和侵袭。

Microstructure and mechanical properties of a cast TRIP-assisted multiphase stainless steel

Stainless steels are used in a wide range of complex environments due to their excellent corrosion resistance.Multiphase stainless steels can offer an excellent combination of strength,toughness and corrosion resistance due to the coexistence of different microstructures.The microstructure and mechanical properties of a novel cast multiphase stainless steel,composed of martensite,ferrite,and austenite,were investigated following appropriate heat treatment processes:solution treatment at 1,050℃ for 0.5 h followed by water quenching to room temperature,and aging treatment at 500℃ for 4 h followed by water quenching to room temperature.Results show reversed austenite is formed by diffusion of Ni element during aging process,and the enrichment of Ni atoms directly determines the mechanical stability of austenite.The austenite with a lower Ni content undergoes a martensitic transformation during plastic deformation.The tensile strength of the specimen exceeds 1,100 MPa and the elongation exceeds 24%after solid solution,and further increases to 1,247 MPa and 25%after aging treatment.This enhancement is due to the TRIP effect of austenite and the precipitation of the nanoscale G-phase pinning dislocations in ferrite and martensite.

轻质中锰钢局部变形带的研究现状

轻质中锰钢是第三代先进高强钢的代表,在变形过程中由于C、Mn、Al等合金元素的存在其可动位错经历被固溶原子和C-Mn原子团钉扎和脱扎的过程,从而在应力-应变曲线上呈现出吕德斯(Lüders)带和Portrvin-Le Chatelier(PLC)带这两种最典型的局部变形带,导致材料表面质量降低,对后续加工使用不利。目前,消除Lüders带和PLC带引起的表面缺陷的常用方法是在成形前对材料施加小的预应变或者调控材料的组织。然而这种方法只适用于经历小Lüders带应变和PLC效应的材料,因此寻求一种更为有效的延迟或消除Lüders带与PLC带的方法显得极其重要。本文从发生机理入手,讨论预应变、退火温度、退火时间等工艺和合金元素对上述两种局部变形带的影响,进而从晶粒尺寸、组织形貌、位错密度等微观角度总结减弱或加剧二者的具体机制,并着重解释不同成分与热处理工艺对C-Mn原子团形成、移动速率和与位错交互时间的影响以及抑制局部变形带的形成与拓展的作用。随后根据已有研究提出的不同解决方案,结合上述宏观与微观影响因素,展望了未来该领域研究的发展。

基于TRIP效应的复相钢的组织特征及强塑性机制

采用扫描电镜(SEM)、电子背散射衍射(EBSD)技术和透射电镜(TEM)对复相钢的微观形貌进行表征,并研究了其基于相变诱导塑性(TRIP)效应的强塑性机制。结果表明,将退火温度设定在单相奥氏体区和(γ+α)两相临界区,由于微观形貌特征的不同致使试验钢的力学性能有着显著的区别。退火温度(915℃)在单相奥氏体区时,微观组织由27%先共析铁素体、56%块状贝氏体以及分布于晶界处的17%残留奥氏体组成;组织中的先共析铁素体,其塑性优于再结晶铁素体,更有利于发挥协调变形作用,通过缓解应力对残留奥氏体的作用而有效发挥其TRIP效应;同时均匀分布于晶界处纵横比>2.0的块状残留奥氏体,在变形过程中由于受到相界面及块状硬质相贝氏体的阻碍,TRIP效应的贡献较大且可在整个应变阶段持续地发生。在晶粒尺寸、组织形貌、晶体学结构、V(C,N)析出和位错塞积,以及TRIP效应的共同作用下,915℃退火后复相钢的综合力学性能最优,屈服强度和抗拉强度分别为756和1135 MPa,强塑积可达到26.446 GPa·%,同时具有优良的伸长率和扩孔性能,分别为23.3%和56%。

Modern Development and Maintaining Self-Developing Identity

Two recent trips to cities in China got me thinking a lot about China’s development and efforts to maintain its identity.While China is developing with strong momentum in every sector,it has succeeded at preserving and upholding its ancient traditions and customs.These trips showed me a country not only keen on technological and infrastructural advancement but also deeply committed to cultural preservation and promotion.In every corner of these cities,I witnessed a harmonious blend of the old and new,a testament to China’s dedication to maintaining its cultural heritage while embracing modernity.