基于简易冲击分解模型的爆轰驱动硅橡胶数值模拟及实验解读

为了反映爆轰驱动下硅橡胶发生冲击分解反应的物理过程,提出了一种简易的硅橡胶冲击分解模型。基于该模型,对爆轰驱动含硅橡胶夹层钢板实验进行了模拟,并分析解读了钢板的自由面速度。结果表明,实验中硅橡胶发生了冲击分解反应,导致钢板的自由面速度曲线出现了首次起跳中间速度平台及首次起跳速度峰值降低的现象。受硅橡胶冲击分解影响,首次入射波压力将在临界冲击分解压力附近弛豫一段时间,再继续升高至最高压力。该压力波作用于钢板的自由面后,出现了自由面速度在中间速度平台停留一段时间,之后继续升高至速度峰值的现象。硅橡胶冲击分解后的气相物质可压缩性较高,首次加载波内较多的能量被用于压缩气体做功,导致首次波传播至自由面时能量衰减,峰值压力降低,首次起跳速度峰值降低。

长直坑道内爆炸冲击波相似规律研究

通过长直坑道内炸药爆炸后冲击波的超压峰值变化研究坑道内爆炸冲击波的相似规律。使用AUTODYN软件建立长直坑道仿真模型,采用映射方法将3.25 kg当量的球形TNT炸药在空气中的爆炸状态映射到长直坑道中,采用经典试验结果对模型进行验证。根据几何相似原理,通过改变坑道尺寸、坑道截面形状、炸点位置和炸药当量建立多组不同的模型,模拟计算得到坑道内爆炸冲击波的超压峰值,分析超压峰值的相似规律。结果表明,保持坑道截面积不变、改变截面形状及保持爆心距与炸药当量的比值不变、改变炸药当量,各模型计算得到的冲击波超压峰值具有相似规律。采用本文方法可对其他满足几何相似原理的坑道内爆炸冲击波参数进行预测,为地下空间设施的安全设计提供参考。

高空强爆炸X射线辐照铝靶板动响应的数值模拟

高空强爆炸所产生的X射线辐照至导弹壳体结构时产生的汽化反冲冲量(blow-off impulse,BOI)及热激波,能够引起目标的动响应破坏。现有的Whitener、BBAY和MBBAY理论模型仅能给出一维近似BOI值,无法处理复杂三维情况并给出对应的热激波峰值压力p,因此,对该问题的研究非常依赖数值计算。利用X射线热激波数值计算程序TSHOCK3D对矩形铝靶板在0.1~3.0 keV范围的普朗克黑体温度和220~400 J/cm^(2)辐射能通量下的汽化反冲冲量及峰值压力进行计算,并与理论模型作了对比分析。结果表明,TSHOCK3D程序可以得到可靠的结果,正辐照靶板中心处近似一维工况下的BOI与Whitener、BBAY和MBBAY三个理论模型下的BOI基本相符。通过单变量分析可得,靶板中BOI和峰值压力p均与入射能通量呈近似线性关系;而对于不同的黑体温度,BOI和峰值压力则在1.5~2.0 keV处存在极大值。

膝骨关节炎疼痛领域热点与前沿的可视化分析

背景:疼痛是膝骨关节炎的主要症状,严重影响老年患者的生活质量。膝骨关节炎疼痛机制复杂,涉及多组织、多学科,需要可视化分析了解其主要内容与研究热点。目的:运用文献计量学可视化软件分析归纳膝骨关节炎疼痛领域的前沿内容和研究热点。方法:从Web of Science核心合集(Web of Science Core Collection,WoSCC)中检索2014-2024年膝骨关节炎疼痛领域的相关文献,运用Citespace、VOSviewer和Bibliometrix R-package三个可视化软件进行文献计量与可视化分析。结果与结论:①膝骨关节炎疼痛研究的发文量呈现逐年递增的趋势;②美国、中国、澳大利亚是该领域10年内发文量排名前三的国家;波士顿大学、悉尼大学、弗洛里达大学是发文量前三的科研机构;《OSTEOARTHRITIS AND CARTILAGE》是出版该领域文献最多的期刊,《PAIN》则是该领域被引次数最多的期刊;发文量最多的作者是Fillingim Roger B,该领域的核心作者之间已经建立了一些稳定的团队,但国际性合作尚有欠缺;③膝骨关节炎疼痛患者的日常管理(运动、心理、智能管理)、疼痛的炎症机制、蛋白组学、联合用药、中枢敏化和疼痛调节是膝骨关节炎疼痛研究的重点内容;人工智能辅助、体外冲击波疗法、射频消融术、神经冷冻术、关节腔内注射血液或细胞制剂可能是该领域的研究前沿。

高原环境爆炸冲击波传播规律及计算模型研究

为研究高原地区的低温低压环境对冲击波传播特性的影响,在海拔1500,3000,4500 m环境下开展了TNT爆炸试验,并使用有限元软件对高原环境TNT的爆炸冲击波进行数值仿真计算,分析了不同海拔对冲击波传播特性的影响规律。对比了Sadovskyi,Kinney-Graham和Sachs修正公式的超压峰值和比冲量计算结果与试验结果,并采用Sachs修正中的温度修正项对Sadovskyi高原超压峰值公式进行了修正。研究结果表明:随着海拔的升高,冲击波的波阵面速度加快,到达时间提前,每升高1 km,冲击波超压峰值下降约2%~4%,比冲量下降约4%;对超压峰值进行修正时,3种修正公式均具有一定的准确性;对比冲量进行修正时,Kinney-Graham修正的比冲量值随比例距离增加呈线性降低,与试验结果吻合较差,庞春桥与Sachs的修正结果随比例距离增加呈指数降低;基于温度项修正的Sadovskyi高原冲击波超压峰值经验公式的平均误差减小了3.1%。该研究结果对于高海拔地区的弹药毁伤效能评估有参考意义。

Ideal Bi‑Based Hybrid Anode Material for Ultrafast Charging of Sodium‑Ion Batteries at Extremely Low Temperatures

Sodium-ion batteries have emerged as competitive substitutes for low-temperature applications due to severe capacity loss and safety concerns of lithium-ion batteries at−20°C or lower.However,the key capability of ultrafast charging at ultralow temperature for SIBs is rarely reported.Herein,a hybrid of Bi nanoparticles embedded in carbon nanorods is demonstrated as an ideal material to address this issue,which is synthesized via a high temperature shock method.Such a hybrid shows an unprecedented rate performance(237.9 mAh g^(−1)at 2 A g^(−1))at−60℃,outperforming all reported SIB anode materials.Coupled with a Na_(3)V_(2)(PO_(4))_(3)cathode,the energy density of the full cell can reach to 181.9 Wh kg^(−1)at−40°C.Based on this work,a novel strategy of high-rate activation is proposed to enhance performances of Bi-based materials in cryogenic conditions by creating new active sites for interfacial reaction under large current.

Spontaneous Orientation Polarization of Anisotropic Equivalent Dipoles Harnessed by Entropy Engineering for Ultra‑Thin Electromagnetic Wave Absorber

The synthesis of carbon supporter/nanoscale high-entropy alloys(HEAs)electromagnetic response composites by carbothermal shock method has been identified as an advanced strategy for the collaborative competition engineering of conductive/dielectric genes.Electron migration modes within HEAs as manipulated by the electronegativity,valence electron configurations and molar proportions of constituent elements determine the steady state and efficiency of equivalent dipoles.Herein,enlightened by skin-like effect,a reformative carbothermal shock method using carbonized cellulose paper(CCP)as carbon supporter is used to preserve the oxygencontaining functional groups(O·)of carbonized cellulose fibers(CCF).Nucleation of HEAs and construction of emblematic shell-core CCF/HEAs heterointerfaces are inextricably linked to carbon metabolism induced by O·.Meanwhile,the electron migration mode of switchable electronrich sites promotes the orientation polarization of anisotropic equivalent dipoles.By virtue of the reinforcement strategy,CCP/HEAs composite prepared by 35%molar ratio of Mn element(CCP/HEAs-Mn_(2.15))achieves efficient electromagnetic wave(EMW)absorption of−51.35 dB at an ultra-thin thickness of 1.03 mm.The mechanisms of the resulting dielectric properties of HEAs-based EMW absorbing materials are elucidated by combining theoretical calculations with experimental characterizations,which provide theoretical bases and feasible strategies for the simulation and practical application of electromagnetic functional devices(e.g.,ultra-wideband bandpass filter).

高压氧可消除高强度间歇冲击微周期训练中的运动性疲劳

背景:高压氧作为新兴的疲劳消除手段之一,在体育领域中得到越来越多的重视和应用。高压氧干预对高强度间歇冲击微周期训练疲劳消除的研究较少。目的:探究高压氧干预对高强度间歇冲击微周期训练运动性疲劳消除效果的影响,并从血液生化指标和代谢组学方面进行相应机制研究。方法:在首都体育学院招募20名男性大学生,随机分为对照组(n=10)和高压氧组(n=10),均进行高强度间歇冲击微周期训练,为期2周,共12次,具体训练方案为先以50%HR_(max)的强度热身10 min,再以90%-95%HR_(max)强度蹬车4 min,重复5组,组间休息2.5 min,最后再进行50%HR_(max)强度蹬车30 min。对照组受试者训练后自然恢复,高压氧组受试者训练后进行高压氧恢复,每次干预60 min,压力为131.722 kPa。在试验前、试验中期、试验后1 d和试验后3 d采集血液分析生化指标及代谢组学指标,并进行主观感觉疲劳量表评分,其中氧化应激指标与疲劳监控指标进行Pearson相关性分析。结果与结论:①运动性疲劳指标变化:与训练前相比,对照组训练后血尿酸、肌酸激酶、白细胞介素6和主观感觉疲劳量表评分均有不同程度的上调,而高压氧组在高压氧干预后血尿酸、肌酸激酶、白细胞介素6和主观感觉疲劳量表评分变化不大;组间相比,对照组试验后1 d血尿酸、肌酸激酶和白细胞介素6水平显著高于高压氧组;②氧化应激指标变化:与训练前相比,对照组训练后超氧化物歧化酶活性降低、丙二醛水平升高,而高压氧组在高压氧干预后超氧化物歧化酶活性升高、丙二醛水平降低;③超氧化物歧化酶与血尿酸、白细胞介素6和主观感觉疲劳量表评分呈负相关;丙二醛与白细胞介素6和主观感觉疲劳量表评分呈正相关;④代谢组学指标变化:显著变化的代谢通路是花生四烯酸代谢和氧化磷酸化代谢,富集通路上差异代谢物质有花生四烯酸、前列腺素D2、白三烯D4等。结果表明,高强度间歇冲击微周期训练导致机体发生氧化应激,促进了运动性疲劳的产生;高压氧可以一定程度改善氧化应激水平,以及引起花生四烯酸代谢和氧化磷酸化代谢,从而减少氧化损伤,调节炎症反应,促进组织修复和运动性疲劳消除。

Septic shock due to cytomegalovirus colitis associated with rituximab use:A case report

BACKGROUND Cytomegalovirus(CMV)infections can cause significant morbidity and mortality in immunocompromised individuals.CMV targets dysfunctional lymphocytes.Chronic rituximab(RTX)therapy can cause B-lymphocyte dysfunction,increasing CMV risk.Rarely,CMV infections present with critical illness such as septic shock.CASE SUMMARY A 64-year-old African American woman presented with generalized weakness and non-bloody watery diarrhea of 4-6 weeks duration.She did not have nausea,vomiting or,abdominal pain.She had been on monthly RTX infusions for neuromyelitis optica.She was admitted for septic shock due to pancolitis.Blood investigations suggested pancytopenia and serology detected significantly elevated CMV DNA.Valganciclovir treatment led to disease resolution.CONCLUSION This case illustrates an extremely rare case of CMV colitis associated with RTX use presenting with septic shock.High suspicion for rare opportunistic infections is imperative in individuals with long-term RTX use.

Prognostic impact of hypernatremia for septic shock patients in the intensive care unit

BACKGROUND Hypernatremia represents a significant electrolyte imbalance associated with numerous adverse outcomes,particularly in cases of intensive care unit(ICU)-acquired hypernatremia(IAH).Nevertheless,its relevance in patients with septic shock remains uncertain.AIM To identify independent risk factors and their predictive efficacy for IAH to improve outcomes in patients with septic shock.METHODS In the present retrospective single-center study,a cohort of 157 septic shock patients with concurrent hypernatremia in the ICU at The First Affiliated Hospital of Soochow University,between August 1,2018,and May 31,2023,were analyzed.Patients were categorized based on the timing of hypernatremia occurrence into the IAH group(n=62),the non-IAH group(n=41),and the normonatremia group(n=54).RESULTS In the present study,there was a significant association between the high serum sodium concentrations,excessive persistent inflammation,immunosuppression and catabolism syndrome and chronic critical illness,while rapid recovery had an apparent association with normonatremia.Moreover,multivariable analyses revealed the following independent risk factors for IAH:Total urinary output over the preceding three days[odds ratio(OR)=1.09;95%CI:1.02–1.17;P=0.014],enteral nutrition(EN)sodium content of 500 mg(OR=2.93;95%CI:1.13–7.60;P=0.027),and EN sodium content of 670 mg(OR=6.19;95%CI:1.75–21.98;P=0.005)were positively correlated with the development of IAH.Notably,the area under the curve for total urinary output over the preceding three days was 0.800(95%CI:0.678–0.922,P=0.001).Furthermore,maximum serum sodium levels,the duration of hypernatremia,and varying sodium correction rates were significantly associated with 28-day in-hospital mortality in septic shock patients(P<0.05).CONCLUSION The present findings illustrate that elevated serum sodium level was significantly associated with a poor prognosis in septic shock patients in the ICU.It is highly recommended that hypernatremia be considered a potentially important prognostic indicator for the outcome of septic shock.

Success of intravenous immunoglobulin and steroids in managing severe COVID-19 following lung transplantation:A case report

BACKGROUND Coronavirus disease 2019(COVID-19)pneumonia with severe septic shock and acute respiratory distress syndrome(ARDS)are critical illnesses for patients following transplant.Intravenous immunoglobulin(IVIG)plays a role in both immune support and inflammation control,especially in immunocompromised patients.This case report describes the first successful experience using IVIG and pulse steroids to manage this critical condition following lung transplantation.CASE SUMMARY A 65-year-old male patient reported a history of chronic obstructive pulmonary disease and poor lung function and received bilateral sequential lung transplantations.Postoperatively,he developed COVID-19 pneumonia,severe septic shock,and ARDS.He recovered from this critical condition after empirical antibiotics administration and veno-venous extracorporeal membrane oxygenation,in addition to IVIG and pulse steroids.CONCLUSION IVIG is a valuable adjunct in managing severe sepsis in lung transplant recipients after COVID-19 infection.We aim,for the first time,to report the success of such a management approach for COVID-19 ARDS and sepsis in the post-lung transplant setting.With further investigations,this is a starting point for wider analysis of such an approach in this setting and consequently helps guide clinical practice for such a challenging patient population moving forward.

Current role of extracorporeal membrane oxygenation for the management of trauma patients:Indications and results

Extracorporeal membrane oxygenation(ECMO)has emerged as a vital circulatory life support measure for patients with critical cardiac or pulmonary conditions unresponsive to conventional therapies.ECMO allows blood to be extracted from a patient and introduced to a machine that oxygenates blood and removes carbon dioxide.This blood is then reintroduced into the patient’s circulatory system.This process makes ECMO essential for treating various medical conditions,both as a standalone therapy and as adjuvant therapy.Veno-venous(VV)ECMO primarily supports respiratory function and indicates respiratory distress.Simultaneously,veno-arterial(VA)ECMO provides hemodynamic and respiratory support and is suitable for cardiac-related complications.This study reviews recent literature to elucidate the evolving role of ECMO in trauma care,considering its procedural intricacies,indications,contraindications,and associated complications.Notably,the use of ECMO in trauma patients,particularly for acute respiratory distress syndrome and cardiogenic shock,has demonstrated promising outcomes despite challenges such as anticoagulation management and complications such as acute kidney injury,bleeding,thrombosis,and hemolysis.Some studies have shown that VV ECMO was associated with significantly higher survival rates than conventional mechanical ventilation,whereas other studies have reported that VA ECMO was associated with lower survival rates than VV ECMO.ECMO plays a critical role in managing trauma patients,particularly those with acute respiratory failure.Further research is necessary to explore the full potential of ECMO in trauma care.Clinicians should have a clear understanding of the indications and contraindications for the use of ECMO to maximize its benefits in treating trauma patients.

Patients admitted in the intensive care unit after solid organ or bone marrow transplantation:Retrospective cohort study

BACKGROUND Solid organ transplantation(SOT)and hematopoietic stem cell transplantation(HSCT)revolutionized the survival and quality of life of patients with malignant diseases,various immunologic,and metabolic disorders or those associated with a significant impairment in a patient's quality of life.AIM To investigate admission causes and treatment outcomes of patients after SOT or HSCT treated in a medical intensive care unit(ICU).METHODS We conducted a single-center,retrospective epidemiological study in the medical ICU at the University Hospital Centre Zagreb,Croatia covering the period from January 1,2018 to December 31,2023.RESULTS The study included 91 patients with either SOT[28 patients(30.8%)]or HSCT[63 patients(69.2%)].The median age was 56(43.2-64.7)years,and 60.4%of the patients were male.Patients with SOT had more comorbidities than patients after HSCT[χ^(2)(5,n=141)=18.513,P<0.001].Sepsis and septic shock were the most frequent reasons for admission,followed by acute respiratory insufficiency in patients following HSCT.Survival rate significantly differed between SOT and HSCT[χ^(2)(1,n=91)=21.767,P<0.001].ICU survival was 57%in the SOT and 12.7%in the HSCT group.The need for mechanical ventilation[χ^(2)(1,n=91)=17.081,P<0.001]and vasopressor therapy[χ^(2)(1,n=91)=36.803,P<0.001]was associated with survival.The necessity for acute renal replacement therapy did not influence patients'survival[χ^(2)(1,n=91)=0.376,P=0.54].In the subgroup of patients with infection,90%had septic shock,and the majority had positive microbiological samples,mostly Gram-negative bacteria.The ICU survival of patients with sepsis/septic shock cumulatively was 15%.The survival of SOT patients with sepsis/shock was 45%.CONCLUSION Patients with SOT or HSCT are frequently admitted to the ICU due to sepsis and septic shock.Despite advancements in critical care,the mortality rate of patients with refractory septic shock and multiorgan failure in this patient population is extremely high.Early recognition and timely ICU admittance might improve the outcome of patients,especially after HSCT.

Cardiovascular involvement in multisystem inflammatory syndrome in children and midterm follow-up from a pediatric tertiary center in India

BACKGROUND In multisystem inflammatory syndrome in children(MIS-C)with coronavirus disease 2019,there was paucity of data from low-income and middle-income countries on cardiovascular involvement and its longitudinal outcomes.We planned to estimate the pattern of cardiovascular involvement among children with MIS-C and its mid-term outcomes.AIM To determine association between cardiovascular abnormalities and clinical and laboratory parameters.To study the time-line for resolution of various abnormalities.METHODS In this prospective study done in a tertiary care hospital,270 were recruited from June 2020 to January 2022.Baseline demographic data and clinical presentation were recorded.Laboratory parameters and echocardiography were done at admission.Follow-up was done at 2 weeks,3 months,6 months and 1 year after diagnosis.Descriptive statistics were used for parametric and non-parametric data.Risk factors were identified by multivariate regression analysis.RESULTS The 211(78.2%)had cardiac involvement and 102 needed intensive care unit(ICU)admission.Cardiovascular abnormalities observed were shock 123(45.6%),coronary dilatation 28(10.4%),coronary aneurysm 77(28.5%),left ventricular(LV)dysfunction 78(29.3%),mitral regurgitation(MR)77(28.5%)and pericardial effusion 98(36.3%).Coronary artery aneurysm/dilatation during follow-up at 2 weeks and 1 year were 25.7%and 0.9%respectively.Multivariate regression analysis revealed breathlessness[odds ratio(OR)=3.91,95%CI:1.25-12.21,P=0.019]and hi-flow nasal cannula(HFNC)support(OR=8.5,95%CI:1.06-68.38,P=0.044)as predictors of cardiovascular involvement.Higher mean age(OR=1.16,95%CI:1.02-1.32,P=0.026),breathlessness(OR=4.99,95%CI:2.05-12.20,P<0.001),gallop(OR=4.45,95%CI:0.41-2.52,P=0.016),MR(OR=3.61,95%CI:1.53-8.53,P=0.004)and invasive ventilation(OR=4.01,95%CI:1.28-12.58,P=0.017)were predictive of LV dysfunction.Altered sensorium(OR=4.96,95%CI:2.23-11.02,P<0.001),headache(OR=6.61,95%CI:1.46-29.92,P=0.014),HFNC(OR=7.03,95%CI:2.04-24.29,P=0.002),non-rebreathing mask usage(OR=21.13,95%CI:9.00-49.61,P<0.001)and invasive ventilation(OR=5.64,95%CI:1.42-22.45,P=0.014)were risk factors for shock.Anemia was a risk factor for coronary involvement(OR=3.09,95%CI:1.79-5.34,P<0.001).CONCLUSION Significant number of children with MIS-C had cardiovascular involvement contributing to higher ICU management.Although shock resolved quickly,resolution of ventricular function and coronary abnormalities were slower,and hence warrants a structured long-term follow-up protocol.

冲击点火反应过程中RDX基PBX炸药的热辐射特性

研究冲击波流场中聚合物黏结炸药的热辐射特性可能是获取相关物质组分温度数据的重要途径。利用二级轻气炮加载技术、瞬态辐射测温方法及粒子速度剖面测量技术,探讨了聚合物黏结炸药/氟化锂窗口界面的热辐射特性及其与界面压力之间的相关性;同时,还优化了聚合物黏结炸药样品制备方法,显著抑制了包裹气体和界面间隙发光背景,给出了界面辐亮度数据及界面温度数据。结果表明,在连续2次冲击加载过程中,界面温度随时间衰减特征与反应产物的等熵膨胀行为密切相关,界面温度反映了界面处产物温度的演化行为,为直接观测点火反应和起爆释能期间非均质复合炸药的反应产物温度数据提供了一种可行的技术途径。

皮瓣缺血再灌注损伤的发病机制及治疗进展

背景:皮瓣移植技术是治疗严重组织缺损的常用外科手术方式,但术后因缺血再灌注损伤容易引发皮瓣坏死,因此提高移植皮瓣的存活率仍是目前重要的研究课题。目的:综述皮瓣缺血再灌注损伤的发病机制及最新治疗进展。方法:检索CNKI、万方和PubMed数据库中2014-2024年发表的相关文献,中文检索词为“皮瓣,缺血再灌注损伤,炎症反应,氧化应激反应,Ca^(2+)超载,细胞凋亡,间充质干细胞,富血小板血浆,信号通路,冲击波,预处理”,英文检索词为“flap,ischemia-reperfusion injury,inflammatory response,oxidative stress,Ca^(2+)overload,apoptosis,mesenchymal stem cells,platelet-rich plasma,signaling pathways,Shock wave,Pretreatment”。通过阅读文章剔除研究内容与文章主题关系不大、质量较差及内容陈旧文献,最终纳入77篇文献进行归纳总结。结果与结论:皮瓣缺血再灌注损伤损伤可能与炎症反应、氧化应激反应、Ca^(2+)超载、细胞凋亡等病理因素有关,引起皮瓣血管内皮细胞凋亡、血管损伤和微循环障碍,最终导致皮瓣坏死。研究发现,间充质干细胞移植、富血小板血浆、信号通路调节剂、冲击波及预处理等治疗方法均可以从不同方向在不同程度上缓解皮瓣缺血再灌注损伤,降低移植皮瓣的坏死率和坏死面积。关于皮瓣缺血再灌注损伤的治疗方法虽然很多,然而临床还未形成统一有效的治疗方法,各种治疗方法的优缺点也未进行对比研究,并且大部分研究都停留在动物实验阶段,临床观察研究甚少,因此未来还需要进行大量研究,逐步由动物实验向临床迈进,以便更好地为临床服务。

强震区隧道洞口段新型墙-板抗减震措施的效果分析

为了进一步提高强震区铁路隧道的安全以及抗震性能,依托包银铁路甘德尔山隧道,运用数值模拟软件FLAC 3D,针对强震区隧道洞口段墙-板和墙-板-减震层的抗减震作用效果进行研究。研究结果表明,与不采用抗减震措施相比较,采取墙-板抗震措施后,横向位移减小了5.95%,竖向位移减小了45.87%,最小安全系数增大了40.91%~49.25%,最大主应力的抗震作用效果达到了63.56%,最小主应力的抗震作用效果为4.04%,最大剪应力抗震作用效果为8.35%;采取墙-板-减震层减震措施后,横向位移减小了13.11%,竖向位移减小了43.88%,最小安全系数增大了65.82%~74.50%,最大主应力的减震作用效果达到了75.11%,最小主应力的减震作用效果为10.21%,最大剪应力减震作用效果为12.80%。采用墙-板-减震层的抗减震措施优于墙-板结构。推荐采用墙-板-减震层措施对甘德尔山隧道进行抗减震加固设计。

面向极端雨季内涝的配电设施涉水抢修触电防护

我国区域极端气候复杂,部分地区的电力设备在雨季内涝时会出现故障甚至漏电风险。为解决内涝条件下电力涉水抢修触电问题,首先,对人体安全电位进行理论分析,得出人体安全电位阈值,阐明人体触电机理;其次,采用有限元分析软件建立电力涉水抢修时的水体散流模型及人体触电模型,计算分析涉水深度对人体电位及心脏电位的影响规律,并对不同防护状态下的防护服内外部电位分布进行仿真计算;最后,通过模拟试验对不同防护状态下的人体电位分布进行验证。研究结果可为电力涉水抢修致人体触电问题的解决提供参考。

体外冲击波治疗骨关节疾病的临床研究进展

通过对体外冲击波(extracorporeal shock wave therapy,ESWT)的作用机理及其在颈椎病、肩周炎等常见疾病中的应用进行综述,指出借助ESWT的空化效应、机械效应等加速新陈代谢和生化反应,从而发挥缓解疼痛、修复神经、抗炎等作用,虽然ESWT的治疗效果与能量密度、作用范围、击打次数存在密切联系,而且治疗效果对剂量具有饱和性,但目前关于ESWT的治疗剂量尚无统一标准规范,需在临床应用中寻求最合适剂量,以期为ESWT对骨关节疾病的防治提供一定的参考和依据。

长持时爆炸冲击波作用下钢梁动力响应分析

大规模爆炸时引起的长持时平面爆炸波会造成结构的整体破坏,与接触爆炸或近场爆炸的破坏模式有显著差异,但相关研究不多。为研究长持时冲击波作用下钢梁的动力响应,首先基于耦合欧拉-拉格朗日方法建立了大型数值激波管模型,然后采用该数值激波管得到作用在钢梁上的反射超压时程,最后通过显式动力学方法研究了冲击波入射方向、持时、超压等参数对钢梁破坏模式的影响规律。结果表明:本文提出的数值激波管模型能较好地模拟长持时爆炸波的绕射现象,可得到可靠的反射超压和冲量时程;随着冲击波入射角度的增加,简支钢梁跨中位移增大;冲击波超压峰值相同时,随着持时的增加,简支梁跨中的最大位移有增大的趋势,最大位移的增长速率则会变缓;简支钢梁在长持时爆炸冲击波作用下容易发生受弯破坏,梁跨中翼缘板会出现局部屈曲现象。