Characteristics and interpretation of the seismic signal of a field-scale landslide dam failure experiment

Outburst floods caused by breaches of landslide dams may cause serious damages and loss of lives in downstream areas; for this reason the study of the dynamic of the process is of particular interest for hazard and risk assessment. In this paper we report a field-scale landslide dam failure experiment conducted in Nantou County, in the central of Taiwan.The seismic signal generated during the dam failure was monitored using a broadband seismometer and the signal was used to study the dam failure process.We used the short-time Fourier transform(STFT) to obtain the time–frequency characteristics of the signal and analyzed the correlation between the power spectrum density(PSD) of the signal and the water level. The results indicate that the seismic signal generated during the process consisted of three components: a low-frequency band(0–1.5 Hz), an intermediate-frequency band(1.5–10 Hz) and a highfrequency band(10–45 Hz). We obtained the characteristics of each frequency band and the variations of the signal in various stages of the landslide dam failure process. We determined the cause for the signal changes in each frequency band and its relationship with the dam failure process. The PSD sediment flux estimation model was used to interpret the causes of variations in the signal energy before the dam failure and the clockwise hysteresis during the failure. Our results show that the seismic signal reflects the physical characteristics of the landslide dam failure process. The method and equipment used in this study may be used to monitor landslide dams and providing early warnings for dam failures.

Experimental research on HEL and failure properties of alumina under impact loading

A series of plate impact experiments on alumina was conducted using a light gas gun in order to further investigate Hugoniot elastic limit(HEL)and failure properties of alumina under shock compression.The velocity interferometer system for any reflector(VISAR)was used to record the rear-free surface velocity histories of the alumina samples.According to the experimental results,the HELs of tested alumina samples with different thicknesses were measured,and the decay phenomenon of elastic wave in shocked alumina was studied.A phenomenological expression between HEL and thickness of sample was presented,and the causes of the decay phenomenon were discussed.The propagation of failure wave in shocked alumina was probed.The velocity and delayed time of failure wave propagation were obtained.The physical mechanism of the generation and propagation of failure was further discussed.

Numerical analysis on seismic response and failure mechanism of articulated pile−structure system in a liquefiable site from shaking-table experiments

This study investigates the seismic response and failure mode of a pile-structure system in a liquefiable site by employing a numerical simulation model combined with the shaking-table results of a soil-pile-structure dynamic system.The pile and soil responses obtained from the numerical simulations agreed well with the experimental results.The slopes of the dynamic shear-stress-shear-strain hysteretic curves at different positions also exhibited a decreasing trend,indicating that the shear strength of the soil in all parts of the foundation decreased.The peak acceleration of the soil and pile was not clearly amplified in the saturated sand layer but appeared to be amplified in the top part.The maximum bending moments appeared in the middle and lower parts of the pile shaft;however,the shear forces at the corresponding positions were not large.It can be observed from the deformation mode of the pile-group foundation that a typical bending failure is caused by an excessive bending moment in the middle of the pile shaft if the link between the pile top and cap is articulated,and sufficient attention should be paid to the bending failure in the middle of the pile shaft.

A qualitative study of nurses’experiences of self-care counseling in migrant patients with heart failure

Objectives:This study aims to enhance researchers’and nurses’understanding of how to best support migrant patients with heart failure in self-care management.Previous research on self-care in heart failure patients has highlighted its importance,particularly among migrant populations.Nurses play an important role in informing and engaging patients with chronic conditions like heart failure to support their active participation in self-care.However,nurses’experiences of providing self-care counseling to migrant populations with heart failure have not been studied.Methods:A qualitative study was conducted.Nurses working with migrant patients with HF(n?13)from different types of facility in Western Sweden were interviewed between October and December 2020.Data were collected using semi-structured interviews and analyzed using inductive thematic analysis.Results:The main theme that emerged from the interviews was the difficulty for nurses“to find balance”in self-care counseling.The nurses during self-care counseling had:“to accept challenges,”“to use creative strategies,”faced“problems related to health literacy,”and“to work according to their(the nurses’)obligations.”It was evident that nurses faced several challenges in counseling migrants in self-care,including language and cultural barriers,time resource constraints,low levels of health literacy,and experienced disharmony between the law and their professional norms.They perceived building caring relationships with their patients to be crucial to fostering health-promoting self-care processes.Conclusions:To increase self-care adherence,nurses must become more sensitive to cultural differences and adapt self-care counseling to patients’health literacy.The findings of this research support and challenge nurses in providing the best counsel to migrant patients with heart failure living in Sweden’s multi-ethnic society.Policymakers in the health care organization should act to facilitate mutual cultural understanding between all involved partners for patient-safe self-care counseling.

Modes of failure with fractional flow reserve guidewires:Insights from the manufacturer and user facility device experience database

BACKGROUND Fractional flow reserve(FFR)measurement is commonly used in the cardiac catheterization laboratory to assess the functional significance of coronary arterial plaques.Robust real-world data on complications and modes of failure of FFR guidewires are limited.AIM To characterize these outcomes by analyzing the post-marketing surveillance data from the United States Food and Drug Administration Manufacturer and User Facility Device Experience(MAUDE)database for commonly used FFR guidewires.METHODS The MAUDE database was queried from January 2010 through April 2020 for 3 FFR guidewires[PressureWireTM X(Abbott),CometTM(Boston Scientific),and VerrataTM(Philips)]by searching for the following events:“Injury”,“malfunction”,“death”,and“other”.This yielded 544 reports.After excluding incomplete reports,486 reports were analyzed.RESULTS Guidewire tip fracture was the most commonly reported mode of failure,in 174(35.8%)cases followed by guidewire kinking(n=152,31.3%),communication failure(n=141,29.0%),and shaft fracture(n=67,13.8%).In total,133(27.4%)device failures resulted in patient adverse events.The most common adverse event was retained guidewire tip,in 71(53.4%)cases,followed by freshly deployed stent dislodgment(n=26,19.6%)and coronary artery dissection(n=23,17.3%).Seven deaths were reported.CONCLUSION FFR guidewire failures can occur because of various mechanisms and cause patient adverse events.The MAUDE database serves as an important platform for improved collaboration among clinicians,device manufacturers,and regulators to improve device performance and optimize patient outcomes.Our analysis provides mechanistic insights of FFR guidewire failure and associated adverse events but cannot verify causality or provide a comparison among different guidewires.

Study on chemical failure of HMX under low temperature condition

In order to make unexploded ordnance lose explosive ability,the chemical failure of HMX that is usually used as detonating explosive and booster was studied so as to find the corresponding chemical reagents,which can decompose HMX into compounds without explosive properties.For this purpose,several decomposition experiments between HMX and NaOH,HMX and thick H2 SO,HMX and mixed acid under different temperature conditions were carried out.According to the experimental results,it can be concluded that HMX can be decomposed by a mixture of concentrated nitric acid and concentrated nitric acid with the volume ratio of 3∶1.When its decomposed level reaches 60%,HMX will not be detonated,therefore the failure purpose is achieved.

Experimental analysis of high temperature capacitance variance of MLCC

High temperature capacitance variance of multi-layer ceramic capacitor （MLCC） is researched.Combined with the characteristics of MLCC,the application of MLCC in fuze is proposed,and the temperature stability of MLCC is also discussed.The experimental results indicate that the capacitance of low frequency MLCC is largely affected by temperature.

Bioartificial liver support systems for acute liver failure: A systematic review and meta-analysis of the clinical and preclinical literature

BACKGROUND Acute liver failure(ALF) has a high mortality varying from 80% to 85% with rapid progress in multi-organ system failure. Bioartificial liver(BAL) support systems have the potential to provide temporary support to bridge patients with ALF to liver transplantation or spontaneous recovery. In the past decades, several BAL support systems have been conducted in clinical trials. More recently,concerns have been raised on the renovation of high-quality cell sources and configuration of BAL support systems to provide more benefits to ALF models in preclinical experiments.AIM To investigate the characteristics of studies about BAL support systems for ALF,and to evaluate their effects on mortality.METHODS Eligible clinical trials and preclinical experiments on large animals were identified on Cochrane Library, PubMed, and EMbase up to March 6, 2019. Two reviewers independently extracted the necessary information, including key BAL indicators, survival and indicating outcomes, and adverse events during treatment. Descriptive analysis was used to identify the characteristics of the included studies, and a meta-analysis including only randomized controlled trial (RCT) studies was done to calculate the overall effect of BAL on mortality among humans and large animals, respectively.RESULTS Of the 30 selected studies, 18 were clinical trials and 12 were preclinical experiments. The meta-analysis result suggested that BAL might reduce mortality in ALF in large animals, probably due to the recent improvement of BAL, including the type, cell source, cell mass, and bioreactor, but seemed ineffective for humans (BAL vs control: relative risk(95% confidence interval),0.27(0.12-0.62) for animals and 0.72(0.48-1.08) for humans)Liver and renal functions, hematologic and coagulative parameters, encephalopathy index, and neurological indicators seemed to improve after BAL, with neither meaningful adverse events nor porcine endogenous retrovirus infection.CONCLUSION BAL may reduce the mortality of ALF by bridging the gap between preclinical experiments and clinical trials. Clinical trials using improved BAL must be designed scientifically and conducted in the future to provide evidence for transformation.

RESEARCH ON DIRECT CURRENT ELECTRIC FIELD CHARACTERISTICS OF OVERBURDEN FAILURE AND ITS APPLICATIONS

The overburden failure causes the changes of the constant electric field, and the resistivity is the main parameter in these changes. The experimental simulation about tbe response relation between the overburden failure and its electrical parameter changes is made by building the similar material physics model of mining. The experiment results are used to analyze and test the in-situ detection. The research indicates that the resistivity changes with the electric characteristic of the rock in cracked zone and caving zone caused by overburden failure, the response characteristics of resistivity vary with the failure degrees at different overburden failure zone and that they are corresponding. The resistivity method used in monitoring the overburden failure can determine the height and the affecting scopes of the cracked zone and caving zone. This can provide reliable techaological guarantee for mining design and safe production.

Mechanism of progressive failure of a slope with a steep joint under the action of freezing and thawing:model test

The stability of slope rock masses is influenced by freeze-thaw cycles in cold region,and the mechanism of stability deterioration is not clear.In order to understand the damage and progressive failure characteristics of rock masses under the action of freezing and thawing,a model test was conducted on slope with steep joint in this study.The temperature,frost heaving pressure and deformation of slope rock mass were monitored in real-time during the test and the progressive failure mode was studied.The experimental results show that the temperature variations of cracking and the rock mass of a slope are different.There are obvious latent heat stages in the temperature-change plot in the crack,but not in the slope rock masses.The frost heaving effect in the fracture is closely related to the constraint conditions,which change with the deformation of the fracture.The frost heaving pressure fluctuates periodically during freezing and continues to decrease during thawing.The surface deformation of the rock mass increases during freezing,and the deformation is restored when it thaws.Freeze-thaw cycling results in residual deformation of the rock mass which cannot be fully restored.Analysis shows that the rock mass at the free side of the steep-dip joint rotates slightly under the frost heaving effect,causing fracture propagation.The fracture propagation pattern is a circular arc at the beginning,then extends to the possible sliding direction of the rock mass.Frost heaving force and fracture water pressure are the key factors for the failure of the slope,which can cause the crack to penetrate the rock mass,and a landslide ensues when the overall anti-sliding resistance of the rock mass is overcome.

Self-care among older Chinese people with chronic heart failure： the roles of cognitive and psychosocial characteristics

Chronic heart failure （CHF） is a complex clinical syndrome resulting from inefficient myocardial pumping, and is characterised by a typical progressively deteriorating trajectory punctuated by serious episodes of acute disease decompensation.High prevalence of hospital admission has been reported.[2] However, around 40% of hospital admissions was avoidable if patients demonstrate consistent self-care.

The Experimental Simulation of Rocks on Load/Unload Response Ratio for Earthquake Prediction

The load/unload experiments on rock failure under pressure have been carried out in Material Test System (MTS) in the Laboratory for Non-linear Mechanics of Continuous Media (LNM), Institute of Mechanics, Chinese Academy of Sciences, and load/unload response ratio (LURR) values with strain as response (i.e. inverse elastic constant as response rate) have been obtained. The experimental results are in accordance with theoretical results and those in real earthquakes: LURR rises just before rock failure. So LURR can be used as the precursor of rock failure and earthquake prediction.

PROGRESSIVE FRAGMENT MODELING OF FAILURE WAVE IN CERAMICS UNDER PLANAR IMPACT LOADING

Polycrystalline ceramics have heterogeneous meso-structures which result in high singularity in stress distribution. Based on this, a progressive fragment model was proposed which describes the failure wave formation and propagation in shocked ceramics. The governing equation of the failure wave was characterized by inelastic bulk strain with material damage and fracture. And the inelastic bulk strain consists of dilatant strain from nucleation and expansion of microcracks and condensed strain from collapse of original pores. Numerical simulation of the free surface velocity was performed in good agreement with planar impact experiments on 92.93% aluminas at China Academy of Engineering Physics. And the longitudinal, lateral and shear stress histories upon the arrival of the failure wave were predicted, which present the diminished shear strength and lost spall strength in the failed layer.

Small Scale Field Experiment on Breaking Wave Pressure on Vertical Breakwaters

A small scale field experiment (SSFE) was performed on vertical breakwaters in the surf zone. The following are some of the findings. Wind seas may yield breaking wave pressure notwithstanding some large deepwater wave steepness, and small elevation of the wall above the mean water level. Caisson breakwaters can withstand some exceptionally high impulsive force peaks (even twice the weight in still water);whereas, with the same sea state and weight, a breakwater composed of layers of solid concrete blocks is destroyed.

电针刺激对慢性心力衰竭模型大鼠及心肌纤维化细胞模型的影响

目的观察电针刺激对慢性心力衰竭(CHF)大鼠模型及心肌纤维化细胞模型的影响,探讨电针对CHF的治疗作用机制。方法选取24只雄性Wistar大鼠随机分为4组,分别为假手术组、假手术+电针组、心肌纤维化组及心肌纤维化+电针组,每组6只。将H9c2大鼠心肌细胞随机分为4组,对照组、对照+电针组、血管紧张素Ⅱ处理组及血管紧张素Ⅱ处理+电针组。心肌纤维化组大鼠采用腹主动脉缩窄法建立CHF模型,假手术组大鼠仅分离腹主动脉不进行钳夹,心肌纤维化+电针组大鼠在心肌纤维化组的基础上联合电针刺激大鼠双侧“内关”穴干预,假手术+电针组大鼠在假手术组的基础上联合电针刺激大鼠双侧“内关”穴干预。血管紧张素Ⅱ处理组采用含血管紧张素Ⅱ的培养基对H9c2大鼠心肌细胞进行培养及传代,对照组H9c2大鼠心肌细胞在正常培养基内进行培养及传代,血管紧张素Ⅱ处理+电针组是血管紧张素Ⅱ处理组的基础上在培养皿中予以电刺激,对照+电针组在对照组的基础上在培养皿中予以电刺激。检测各组大鼠干预12、16、20周室间隔舒张末期厚度(IVSd)、左室舒张末期后壁厚度(LVPWd)、左室收缩末期内径(LVEDs)、左室舒张末期内径(LVEDd)及左室射血分数(LVEF),以及血清B型钠尿肽(BNP)、乳酸脱氢酶(LDH)、肌酸激酶(CK)水平,检测各组H9c2大鼠心肌细胞在干预12、16、20周重组蛋白基质金属蛋白酶9(MMP9)及基质金属蛋白酶抑制剂-1(TIMP-1)相对表达情况。结果与假手术组干预同期比较,心肌纤维化组干预12、16、20周时IVSd、LVPWd、LVEDs及LVEDd均升高(P<0.05),LVEF降低(P<0.05),但假手术+电针组干预12、16、20周时各项指标与假手术组干预同期比较差异均无统计学意义(P>0.05)。与心肌纤维化组干预同期比较,心肌纤维化+电针组干预12、16、20周时IVSd、LVPWd、LVEDs及LVEDd均降低(P<0.05),LVEF升高(P<0.05)。与假手术组干预同期比较,心肌纤维化组干预12、16、20周时BNP、LDH及CK水平均升高(P<0.05),但假手术+电针组干预12、16、20周时各项指标与假手术组干预同期比较差异均无统计学意义(P>0.05)。与心肌纤维化组干预同期比较,心肌纤维化+电针组干预12、16、20周时BNP、LDH及CK水平均降低(P<0.05)。与对照组干预同期比较,血管紧张素Ⅱ处理组干预12、16、20周时MMP-9及TIMI-1相对表达水平均升高(P<0.05),但对照+电针组干预12、16、20周时各项指标与对照组干预同期比较差异均无统计学意义(P>0.05)。与血管紧张素Ⅱ处理组干预同期比较,血管紧张素Ⅱ处理+电针组干预12、16、20周时MMP-9及TIMI-1相对表达水平均降低(P<0.05)。结论电针对CHF的治疗作用可能是通过抑制心室重构,改善心功能,保护心肌细胞,减轻心肌纤维化而实现。

八段锦联合广播体操对慢性心力衰竭患者相关指标及预后的影响

目的分析八段锦联合广播体操对慢性心力衰竭患者相关指标及预后的影响。方法选取2022年10月至2023年10月鄂尔多斯市中心医院收治的100例慢性心力衰竭患者作为研究对象,依据随机数字表法将研究对象分为对照组及试验组,两组各50例;两组均给予常规药物治疗,在此基础上,对照组给予常规运动康复治疗,试验组给予八段锦联合广播体操运动康复治疗,两组均干预6个月,对比两组干预前后超声心动图、心肺运动试验相关指标、N末端B型利钠肽原(NT-proBNP)水平及不良心血管事件(MACE)发生率。结果运动康复治疗前,对照组与试验组的各项指标比较组间差异无统计学差异(P>0.05)。治疗6个月后,试验组患者左心室射血分数(LVEF)和左室短轴缩短率(LVFS)明显高于治疗前(P<0.05),NT-proBNP和左心室舒张末期内径(LVEDD)明显低于治疗前(P<0.05);对照组患者LVEF和LVFS明显高于治疗前(P<0.05),NT-proBNP明显低于治疗前(P<0.05),LVEDD较治疗前无明显变化(P>0.05);试验组患者的LVEDD和NT-proBNP明显低于对照组[(54.33±6.58)mm比(58.60±5.23)mm、(1037.37±352.94)pg/ml比(1503.86±610.97)pg/ml,P<0.05],LVEF和LVFS明显高于对照组[(51.89±4.98)%比(47.98±5.86)%,P<0.05]。试验组患者MET、Peak VO_(2)/kg、Peak O2pulse明显高于治疗前(P<0.05);对照组患者的MET、Peak O2pulse明显高于治疗前(P<0.05),Peak VO_(2)/kg较治疗前无明显变化(P>0.05);试验组的MET、Peak VO_(2)/kg、Peak O2pulse明显高于对照组[(5.52±0.99)比(4.59±0.70)、(16.37±1.71)ml·kg^(-1)·min^(-1)比(15.36±1.44)ml·kg^(-1)·min^(-1)、(9.87±1.68)ml/beat比(9.15±1.60)ml/beat,P<0.05]。试验组的MACE发生率和对照组相比无统计学意义(P>0.05)。结论八段锦联合广播体操可能较常规康复治疗更能够改善CHF患者的心肺功能、运动耐量及预后。

心力衰竭患者居家安宁疗护期间照顾者照护体验的质性研究

目的调查心力衰竭患者居家安宁疗护期间照顾者的真实照护体验和需求,为缓解照顾者照护压力、提高照护能力、改善患者居家安宁疗护期间生活质量提供参考。方法选取心力衰竭患者居家安宁疗护期间的16名照顾者进行访谈,采用Colaizzi现象学分析法对访谈资料进行整理分析。结果心力衰竭患者居家安宁疗护期间照顾者照护体验可归纳为3个主题:选择安宁疗护后复杂情绪体验;角色适应不良与应对;渴望获得多方面支持。结论应采取多种措施给予照顾者专业和情感等方面支持,协助照顾者角色适应,提高心力衰竭患者居家安宁疗护期间的照护质量。

集成电路固有失效机理的可靠性评价综述

ULSI/VLSI集成电路芯片的可靠性既与设计有关,也与工艺加工过程有关,即芯片的可靠性是设计进去、制造出来。设计是集成电路芯片可靠性的基础,工艺制造是集成电路芯片可靠性的实现。要使超大规模集成电路在特定的寿命期间内能够稳定地工作,必须对影响集成电路芯片可靠性的固有失效机理进行评价。评价的目的是确定磨损失效的机理,通过改进设计和工艺加工水平确保集成电路芯片在整个产品寿命期间有良好的可靠性。本文梳理了国内外集成电路芯片固有失效机理的可靠性评价标准,阐述了这些固有失效机理的产生机制,总结了不同固有失效机理的试验方法,提出了固有失效机理的可靠性评价要求。这些标准、方法和可靠性评价要求具有很强的时效性,集成电路芯片固有失效机理的可靠性评价将在工艺开发、建库及工程服务中发挥作用,并有助于推动国内合格生产线认证的开展。

健心颗粒联合沙库巴曲缬沙坦钠片对心力衰竭大鼠心功能和左室重构的影响

目的:观察健心颗粒联合沙库巴曲缬沙坦钠片对心力衰竭大鼠心功能和左室重构的影响。方法:采用改良的大鼠心力衰竭模型构建方法,将心衰模型大鼠随机分为模型组、单纯西药组、中西联合组,并设置假手术组作为对照组,分别予生理盐水、沙库巴曲缬沙坦钠片、健心颗粒联合沙库巴曲缬沙坦钠片治疗,连续干预8周后比较各组大鼠左心室射血分数(LVEF)、左心室舒张内径(LVIDd)、左心室收缩内径(LVIDs)、左心室缩短分数(LVFS)、N末端前体脑利钠肽(NT-proBNP)水平。结果:干预后,与模型组比较,单纯西药组、中西联合组大鼠LVIDd、LVIDs、LVEF、LVFS、NT-proBNP水平均改善明显(P<0.05);与单纯西药组比较,中西联合组LVEF、LVFS、NT-proBNP水平明显改善(P<0.05)。结论:健心颗粒联合沙库巴曲缬沙坦钠片能更显著提高心力衰竭大鼠的心功能和左室重构,疗效更好。

国医大师夏桂成论中医女性生殖节律理论的“节”和“律”

分述女性生命中五种节律(昼夜节律、周节律、月节律、年节律、生命节律)特征以及夏桂成教授基于生殖节律理论治疗妇科临床疾病的经验。昼夜节律是生命节律的基本单位,白天活动振奋阳气,夜间安睡静养阴血是最基本的养生准则。七为少阳数,女性的经期常持续7天,阴分充足“锦丝带”(像锦缎一样的阴道分泌物)也可达7天,更有助成孕。月经周期节律上应月下应潮,夏教授提出了经典的四期月经周期节律学说,后为了更好地描述阴阳变化,又将经典的四期分为七期,以更好地指导临床。并附验案1则。