基于SMCS模型的高强螺栓及节点火灾全过程断裂性能模拟

高强螺栓广泛应用于钢结构节点连接,火灾高温会影响其基本材性和断裂行为,从而影响螺栓节点抗火性能甚至整体结构抗倒塌性能。基于10.9级高强螺栓火灾全过程(升温段、降温段、火灾后)单轴拉伸试验结果,结合有限元模拟,对不同温度历程和应力三轴度对应的螺栓SMCS断裂模型进行校准,并与螺栓材性试验和T-stub节点试验结果对比验证;对T-stub节点火灾全过程断裂行为进行参数分析,研究损伤准则和温度历程对节点失效模式和变形特征的影响。结果表明:校准的SMCS模型能够有效、准确地预测螺栓和节点在火灾全过程和高应力三轴度(0.3~1.2)下的受拉断裂行为,适用预测误差在12%以内;拉伸温度和峰值温度是影响高强螺栓抗断能力的主要因素,螺栓抗断能力随温度升高而提高;不同温度历程下T-stub节点可能发生翼缘板屈服断裂、翼缘板和螺栓同时屈服断裂、螺栓屈服断裂三种失效模式,且节点的变形能力(延性系数)与失效模式有关,确定钢板母材和螺栓的断裂模型是准确预测节点失效模式的关键。

基于文本策略和SMCS的海量日志分析方法

现有的海量日志统计分析方法速度慢,且对硬件配置的要求高。为此,提出一种基于文本策略和SMCS的海量日志分析方法。根据文件的软件设计策略,采用日志文件索引方法,将日志文件与日志时间关联,以加快日志提取。SMCS算法采用哈希表、文件归并、堆操作方法对海量日志进行统计分析和内存损耗控制。通过对真实软件进行对比实验,结果表明,该方法的分析速度比传统方法提高4倍。

基于SMCS的多源空间数据集成应用

为解决多源空间数据特别是不同参考基准数据实时集成困难的问题,通过分析空间元数据间关系,定义并利用元数据知识来实现空间元数据的动态聚合和目录服务SMCS的构建。实验结果表明顾及空间关系的SMCS提高了对空间信息的动态获取、处理和发布的能力和效率,为网格环境下多源数据的高效集成应用服务提供技术支持。

EXPERIMENTAL STUDY OF APOPTOSIS OF SMCs IN VITRO BY (32)~P WITH BALLOON CATHETER

Objective To study the apoptosis of cultured rabbit smooth muscle cells (SMCs) by low dose 32Pperfused in balloon catheter and its doseresponse relationship differences. Methods Liquid 32P isotope wasinfused directly into the balloon of PTCA catheter, to irradiate the SMCs with various doses. Light microscope,electron microscope, agarose gel electrophoreses and flow Cytometry(FCM) were used to detect the apoptosis ofSMCs after 24h irradiation. Results The irradiated SMCs showed condensation of the cytoplasm, chromatincondensation, chromosal clumping and margination, apoptotic body and the nuclear DNA degradation on agarose,the amount of SMC opoptosis was positively correlated with the different doses in FCM. Conclusion Our dataidentified irradiation with 32P isotopefilled balloon can be the induction of SMCs apoptosis. Further study isrequired to determine potential value of this method about prevention of restenosis resulting from decreasing ofSMCs proliferation.

基于SMCS模型高强度管线钢韧性失效的预测

为确保高强度管线钢油气管道的输运安全,韧性断裂的设计与评估至关重要,考虑微结构孔洞损伤演化并有效结合宏观有限元结构分析的应力修正临界应变(SMCS)模型适用于韧性失效的预测。借鉴X80管线钢缺口试件拉伸实验数据,采用Gurson损伤模型有限元模拟了该试件的韧性起裂,结果表明:韧性起裂位置发生在试件中心;构成孔洞体积比增加的主要贡献来自孔洞扩张,孔洞形核对韧性起裂影响较小,由此验证了SMCS模型的相关假设。在此基础上,得到了该型管线钢的韧性失效指标与失效准则,该失效准则形式简单,便于工程应用。

SMC再生SBS沥青的流变性能和微观特性研究

【目的】探究新型温拌再生剂甲基苯乙烯共聚物(styreneic methyl copolymer,SMC)对老化苯乙烯系热塑性弹性体(styrene butadiene styrene,SBS)改性沥青的再生效果和再生机理。【方法】首先,在室内制备不同老化程度的沥青。然后,采用SMC再生剂对不同老化程度的SBS改性沥青进行再生。接着,对再生后的SBS改性沥青进行动态剪切流变和低温弯曲蠕变试验,以评价其流变性能。最后,开展红外光谱试验以揭示其作用机理,进行电镜扫描试验以验证SMC再生剂的再生效果。【结果】SMC再生剂会降低老化SBS改性沥青的车辙因子,降低老化SBS改性沥青的恢复率,同时会使老化SBS改性沥青的低温性能得到极大提升。SMC再生剂未与SBS改性沥青发生化学反应,两者仅为物理共混。同时,SMC再生剂能够弥补沥青因老化产生的裂缝。【结论】SMC再生剂对老化SBS改性沥青具有较好的修复效果,能够为沥青的再生提供一种新的途径。

基于双环自适应滑模的移动机器人轨迹跟踪控制

为了提升移动机器人轨迹跟踪精度,针对传统双环控制内外环协调性差、抗扰性弱的问题,文章提出双环自适应滑模的控制方法。为消除传统滑模控制(sliding mode control, SMC)方法中的趋近阶段,设计新型时变积分终端滑模控制器以保证系统状态始终位于滑模面,并通过控制器参数调节实现内环姿态误差和外环位置误差的快速收敛;构建基于势垒函数的增益调控方法,保证在扰动上界未知的情况下有效地抑制状态抖振,提高轨迹跟踪系统的抗干扰能力。对所提方法进行的验证分析结果表明,相较于现有的双环控制方法,该文轨迹跟踪控制方法精度更高、鲁棒性更强。

BDS-3 B2b-PPP URA评估精化与播发方法

用户距离精度指数(URAI)作为导航系统定位服务完好性标识,在提供卫星可用性信息的同时,也反映了卫星的轨道钟差精度。本文提出将B2b电文中随轨道改正数播发的URAI信息恢复为用户距离精度(URA),并用于B2bPPP的随机模型构建。对其进行定位性能评估,发现B2b自身播发的URA精度较差。针对该问题,利用分布在中国及周边区域的多个全球卫星导航系统(GNSS)监测站对B2b的URA参数进行重估计。实验结果表明:精化后的URA能显著提升B2b-PPP的服务性能。相比于仅考虑观测噪声和高度角的随机模型,使用精化后的URA作为随机模型,动态和静态定位模式下的收敛时间提升分别达到18.9%、14.5%;收敛后定位精度提升分别达到11.2%、8.9%。在此基础上,进一步结合北斗卫星导航系统(BDS)短报文,提出一种精化后URA的播发方法,结合现有短报文通信效率进一步分析了精化URA的用户使用性能。

人工林种植和生长对黄土高原生态系统固碳和水文调节功能的影响——基于遥感时序分析证据

随着生态恢复工程的进展,黄土高原人工林种植面积不断增加,黄土高原人工林生态系统服务功能的响应变化仍存在争议。基于黄土高原人工林的时空分布和种植年份信息,从生态系统净初级生产力(NPP)、蒸散发(ET)以及土壤含水率(SMC)三个维度评估黄土高原地区人工林生态系统固碳和水文调节服务功能的动态变化及其对天然林和整个区域生态系统功能的影响,并进一步研究2000—2020年间人工林林龄对生态系统服务功能的影响。天然林的NPP相对于整个区域的百分比基本保持不变,维持在21%左右;而人工林的NPP相对于整个区域的百分比显著增加,并在2009年超过了天然林,成为黄土高原NPP增加的主要来源。人工林占整个区域的ET百分比和SMC百分比均显著增加,分别由不到2%增长至13.9%、1.5%上升至11.8%。至2015年,黄土高原人工林的ET和SMC已经逐步趋于稳定。随着林龄增大,SMC变化速率和变化量不断下降。ET与林龄成正相关,而SMC与林龄负相关,表明具有不同年龄结构的人工林将有效减弱树木生长所引起的土壤干旱的影响。尽管黄土高原人工林林龄与NPP、ET和SMC变化速率和变化量之间存在显著相关性(P<0.01),但由于现阶段此地区人工林多为幼龄林和中龄林,未来这种显著相关关系是否持续有待进一步研究。

The DNA damage repair complex MoMMS21-MoSMC5 is required for infection-related development and pathogenicity of Magnaporthe oryzae

The conserved DNA damage repair complex,MMS21-SMC5/6(Methyl methane sulfonate 21-Structural maintenance of chromosomes 5/6),has been extensively studied in yeast,animals,and plants.However,its role in phytopathogenic fungi,particularly in the highly destructive rice blast fungus Magnaporthe oryzae,remains unknown.In this study,we functionally characterized the homologues of this complex,MoMMS21 and MoSMC5,in M.oryzae.We first demonstrated the importance of DNA damage repair in M.oryzae by showing that the DNA damage inducer phleomycin inhibited vegetative growth,infection-related development and pathogenicity in this fungus.Additionally,we discovered that MoMMS21 and MoSMC5 interacted in the nuclei,suggesting that they also function as a complex in M.oryzae.Gene deletion experiments revealed that both MoMMS21 and MoSMC5 are required for infection-related development and pathogenicity in M.oryzae,while only MoMMS21 deletion affected growth and sensitivity to phleomycin,indicating its specific involvement in DNA damage repair.Overall,our results provide insights into the roles of MoMMS21 and MoSMC5 in M.oryzae,highlighting their functions beyond DNA damage repair.

Asynchronous Learning-Based Output Feedback Sliding Mode Control for Semi-Markov Jump Systems: A Descriptor Approach

This paper presents an asynchronous output-feed-back control strategy of semi-Markovian systems via sliding mode-based learning technique.Compared with most literature results that require exact prior knowledge of system state and mode information,an asynchronous output-feedback sliding sur-face is adopted in the case of incompletely available state and non-synchronization phenomenon.The holonomic dynamics of the sliding mode are characterized by a descriptor system in which the switching surface is regarded as the fast subsystem and the system dynamics are viewed as the slow subsystem.Based upon the co-occurrence of two subsystems,the sufficient stochastic admissibility criterion of the holonomic dynamics is derived by utilizing the characteristics of cumulative distribution functions.Furthermore,a recursive learning controller is formulated to guarantee the reachability of the sliding manifold and realize the chattering reduction of the asynchronous switching and sliding motion.Finally,the proposed theoretical method is substantia-ted through two numerical simulations with the practical contin-uous stirred tank reactor and F-404 aircraft engine model,respectively.

Robust design of sliding mode control for airship trajectory tracking with uncertainty and disturbance estimation

The robotic airship can provide a promising aerostatic platform for many potential applications.These applications require a precise autonomous trajectory tracking control for airship.Airship has a nonlinear and uncertain dynamics.It is prone to wind disturbances that offer a challenge for a trajectory tracking control design.This paper addresses the airship trajectory tracking problem having time varying reference path.A lumped parameter estimation approach under model uncertainties and wind disturbances is opted against distributed parameters.It uses extended Kalman filter(EKF)for uncertainty and disturbance estimation.The estimated parameters are used by sliding mode controller(SMC)for ultimate control of airship trajectory tracking.This comprehensive algorithm,EKF based SMC(ESMC),is used as a robust solution to track airship trajectory.The proposed estimator provides the estimates of wind disturbances as well as model uncertainty due to the mass matrix variations and aerodynamic model inaccuracies.The stability and convergence of the proposed method are investigated using the Lyapunov stability analysis.The simulation results show that the proposed method efficiently tracks the desired trajectory.The method solves the stability,convergence,and chattering problem of SMC under model uncertainties and wind disturbances.

SMC1A基因突变的儿童急性髓系白血病1例预后分析及文献复习

目的探讨合并SMC1A基因突变的儿童急性髓系白血病(AML)治疗经验及预后。方法对潍坊市人民医院2021年6月收治的1例SMC1A基因突变的AML病儿资料进行回顾性分析,验证突变来源,并复习相关文献分析该突变对AML发病、治疗尤其是供体选择及预后的影响,随访截止时间为2022年8月。结果男,7岁,因“腹部外伤伴血尿并发现白细胞增高3 d”就诊,入院诊断AML(M1),血液肿瘤全转录组检测检出FLT3-ITD,CEBPA P23fs及SMC1A R586P三处基因变异。Sanger测序验证该病儿SMC1A基因突变为体细胞突变而非胚系突变,为移植供体选择同胞全相合弟弟提供依据。结论对于存在SMC1A基因突变的病儿,验证突变来源并结合文献对基因突变进行分析,有助于及时调整诊疗方案,了解疾病预后。

Extension of Chemoprevention of Seasonal Malaria to Five Cycles and to Children from the Age of 6 to 9 Years in Africa: Analysis of Its Acceptability, Feasibility, Cost and Impact A Systematic Review

Introduction: Seasonal Malaria Chemoprevention (SMC) aims at preventing malaria in children during the high transmission season. It has been recommended by the WHO since 2013 for children from the age of 3-59 months. However, despite the impact of this intervention, a peak in the prevalence and incidence of malaria is observed in children from the age of 5-9 years. The aim of this study is to determine from the current literature the feasibility, impact and cost-effectiveness of extending SMC to five cycles and to older children. Methods: A litterature search of PubMed/Medline, NCBI and Google scholar identified 1333 articles. After reading the titles and abstracts by two authors, 24 articles were selected and submitted for full reading. Random control studies on the extension of SMC, malaria, feasibility of SMC, impact of SMC and cost-effectiveness of SMC were selected. A total of 16 articles were included for the qualitative synthesis after excluding 8 studies. Results: Following the summary of the evidence, we conclude that the extension is feasible but will be confronted with the unavailability of older children. The intervention period coincides with field work. SMC is effective in reducing the prevalence and incidence of malaria and the parasite density in children. The financial cost of administering SMC is lower than that of treating a child suffering from malaria. Conclusion: After analysing the information, it was found that the majority of the African population supports the extension of the SMC to the number of cycles and the age group in order to alleviate the high mortality and morbidity rates among children due to malaria.

NCAPG、LGALS1在非小细胞肺癌组织中的表达及其对患者预后的影响

目的探讨非小细胞肺癌(NSCLC)中非SMC缩合蛋白I复合物亚基G(NCAPG)、半乳糖凝集素1(LGALS1)的表达及对NSCLC患者预后的预测价值。方法回顾性分析2018年2月至2020年2月在该院接受手术治疗的92例NSCLC患者临床资料。根据随访情况将NSCLC患者分为死亡组和生存组。采用免疫组织化学法检测癌组织和癌旁组织中NCAPG、LGALS1表达情况。采用Kaplan-Meier(简称K-M)生存曲线和多因素Cox回归分析NCAPG、LGALS1表达对NSCLC患者预后的影响。结果癌组织中NCAPG、LGALS1阳性率分别为69.57%(64/92)、67.39%(62/92),明显高于癌旁组织的8.70%(8/92)、6.52%(6/92),差异均有统计学意义(χ^(2)=71.556、73.152,P<0.001)。TNM分期ⅢA期、有淋巴结转移的NSCLC患者癌组织中NCAPG、LGALS1阳性率高于TNM分期Ⅰ~Ⅱ期、无淋巴结转移的NSCLC患者癌组织中NCAPG、LGALS1阳性率,差异均有统计学意义(P<0.05)。随访期间,共死亡患者54例,3年总生存率为41.30%(38/92)。根据随访情况,将NSCLC患者分为死亡组54例,生存组38例。死亡组TNM分期ⅢA期、有淋巴结转移、NCAPG阳性、LGALS1阳性比例明显高于生存组,差异均有统计学意义(P<0.05)。K-M生存曲线分析显示,NCAPG阳性、LGALS1阳性患者3年累积生存率分别低于NCAPG阴性、LGALS1阴性患者,差异均有统计学意义(Log-Rankχ^(2)=13.480、32.701,P<0.001)。多因素Cox回归分析结果显示,NCAPG阳性、LGALS1阳性是NSCLC患者死亡的独立危险因素(P<0.05)。结论NCAPG、LGALS1在NSCLC中阳性率升高,与NSCLC肿瘤TNM分期、淋巴结转移有关,是NSCLC患者死亡的危险因素。

借助他方试验预测自磨/半自磨单位能量的方法

自磨/半自磨单位能量是自磨/半自磨设备选型的主要参数。自磨/半自磨单位能量预测是自磨/半自磨流程设计的重要环节。目前自磨/半自磨单位能量大多通过现代自磨/半自磨试验方法进行预测,这些试验方法一般由专门开发的实验室试验和计算机模拟软件组成,各自形成独立的体系。然而,有一些特殊类型的自磨/半自磨单位能量预测方法不是开发自己的试验方法,而是借用Bond功指数试验、JKTech落重试验、半自磨功率指数(SPI)试验等他方的现有成熟试验方法获得必要的参数,用于自己开发的预测计算方法中,以低成本享有其存在的空间和独特的优势。本文介绍了利用Bond功指数的方法、澳大利亚Ausenco公司的方法、加拿大OMC公司的方法和澳大利亚DBC公司的方法等4种这一类自磨/半自磨单位能量的预测方法。

建筑钢材微观损伤模型的韧性参数校正

Q235B和Q345B钢材在中国建筑领域应用广泛,但却缺乏该类钢材的微孔扩张模型(VGM)和应力修正临界应变(SMCS)模型等微观损伤模型韧性参数,且关于断裂方面的研究缺乏监测到钢材断裂时刻的应力与应变,而无法正确对韧性参数进行校正.笔者取材自母材、热影响区、焊缝区的3种Q235B和Q345B钢材,加工了36个缺口圆棒试件,通过系列单轴拉伸实验,获得了Q235B和Q345B钢材的VGM和SMCS模型韧性参数,然后利用有限元计算VGM模型和SMCS模型对Q235B和Q345B钢材韧性断裂的预测效果.结果表明:VGM模型和SMCS模型对Q235B钢材破坏荷载的预测程度可以控制在25%,以内,对Q345B钢材的预测可以控制在10%,以内,两种模型对破坏荷载的预测程度精准于对破坏位移的预测程度.

Coverage and Factors Associated with Acceptance and Satisfaction of Seasonal Malaria Chemoprevention in Six Health Zones in Benin

Introduction: Seasonal malaria chemoprevention (SMC) was adopted in 2019 in two health zones in Benin where malaria transmission is very high. Positive results led to the extension of the intervention to other zones with additional financial support. Annual SMC campaigns from 2021 to 2023 were carried out in all six health zones in the Atacora and Alibori departments. In five years of implementation, various approaches have been developed on the basis of a communication plan facilitating buy-in and acceptance by all stakeholders. The aim of this study was to assess the effective coverage and acceptance of the SMC by their beneficiary populations in 2023. Methods: It was a cross-sectional study with an analytical focus. Data collection took place from November 30 to December 13, 2023. The study population consisted of children under 5 years of age residing in the departments of Atacora and Alibori in northern Benin. A total of 3573 children under 5 years of age were included in the study, and their parents or guardians were interviewed. Results: During the 2023 campaign, 87.7% of targets were reached by SMC administration and 100.00% of children had received at least one dose of SMC by the fourth visit. Effective therapeutic coverage of SMC was 70.55%, with 99.60% in BNK, 69.40% in KGS, 16.20% in MK, 56.10% in 2KP, 92.40% in NBT and 89.60% in TMC. This coverage was statistically related to child and respondent ages (p Conclusion: SMC is a strategy accepted by the population, and the main reasons for non-participation in SMC were dominated by the absence of mothers or babysitters when the agents visited.

模压工艺在树脂基复合材料中的应用

模压成型工艺具有生产效率高、尺寸控制精度高、表面质量好、可一次成型复杂结构制品等优点,在复合材料成型工艺中占据重要地位。而SMC、GMT、LFT作为模压工艺中主要的成型工艺,其使用范围越来越广泛。为进一步了解SMC、GMT、LFT工艺特点,本文根据目前国内外复合材料模压工艺发展状况,针对SMC、GMT、LFT的工艺原理、工艺路线、未来趋势及前景进行了详细阐述,同时对各工艺所制成的复合材料制品力学性能与物理性能进行对比,为复合材料模压工艺的应用提供了参考。

Monitoring Adverse Events during Seasonal Malaria Chemoprevention Campaigns for Children Aged 3 - 59 Months in Benin in 2023

Background: Seasonal malaria chemoprevention (SMC) is crucial for reducing the burden of malaria in children. However, adverse events (AEs) can affect treatment adherence and efficacy. This study assesses the prevalence of AEs associated with SMC and identifies factors associated with treatment discontinuation. Methods: A cross-sectional study of 3115 children receiving SMC was conducted. The study was conducted in two departments in northern Benin. The prevalence of AEs and factors associated with discontinuation of treatment were analyzed. Results: Among the children, 578 (18.6%, 95% CI: 17.2 - 19.9) reported AEs, mainly vomiting (63.5%), fever (43.8%) and diarrhea (23.0%). Boys (51.9%) had slightly more AEs than girls (48.1%). The prevalence of AEs was higher in rural areas (64.0%) than in urban areas (36.0%). Only 2.8% of children stopped taking SMC because of AEs. There was no significant association between AEs and discontinuation of SMC (p = 0.608). Children referred to health centers for management of AEs were less likely to discontinue treatment (p = 0.015). Conclusion: AEs were common, but the rate of discontinuation of SMC due to AEs was low, indicating good treatment tolerance. Effective management of AEs in health centers reduces treatment interruptions.