Effect of stress level on fatigue behavior of 2D C/C composites

Laminated carbon fiber clothes were infiltrated to prepare carbon fiber reinforced pyrolytic carbon （C/C） using isothermal chemical vapor infiltration （CVI）. The bending fatigue behavior of the infiltrated C/C composites was tested under two different stress levels. The residual strength and modulus of all fatigued samples were tested to investigate the effect of maximum stress level on fatigue behavior of C/C composites. The microstructure and damage mechanism were also investigated. The results showed that the residual strength and modulus of fatigued samples were improved. High stress level is more effective to increase the modulus. And for the increase of flexural strength, high stress level is more effective only in low cycles. The fatigue loading weakens the bonding between the matrix and fiber, and then affects the damage propagation pathway, and increases the energy consumption. So the properties of C/C composites are improved.

Fatigue Properties of RPC under Cyclic Loads of Single-stage and Multi-level Amplitude

Fatigue properties of Reactive Powder Concrete （RPC） under axial compression of single-stage and multi-level amplitude in cycles were studied. The tests reveal the fatigue life, the strain and residual life of the RPC samples. Through the analysis of the test results under cyclic loads of single amplitude, the S-N curve of RPC and the evolution rule of macro-damage of RPC were presented, which can be divided into latency stage, stable development stage and instability development stage according to the evolution pattern of the fatigue crack. Accordingly, the development of longitudinal deformation presents the similar three-stage-model, and the proportion of each stage is 15%, 75%, and 10%. According to test results, the fatigue strength reduction factor is 0.564. We brought forward an empirical formula to predict the life of RPC via total longitudinal strain and got the evolving rule for the residual strength of the RPC. The analysis of the test results under cyclic loads of multi-level amplitude shows that the strain under this loading pattern experiences three stages. The characteristic value for the residual strain was obtained. The irreversible damage and non-linear evolution of RPC was described by the development of the residual plastic strain.

Effects of Physical Activity Levels on Fatigue Perception in Patients with Parkinson’s Disease and Neurologically Healthy Individuals

Background: Recent researches involving fatigue and Parkinson’s disease (PD) sought to verify its incidence and the impacts of fatigue on quality life of patients with PD. Despite the importance of regular physical activity practice, there are only few studies that verified the influence of the levels of physical activity on fatigue in patients with PD. Objective: The aim of this study was to compare perception of fatigue between individuals with PD and neurologically healthy individuals (control group), considering the physical activity levels;and to verify the relation between physical activity levels and fatigue dimensions for individuals with PD and control group. Methods: Eighty individuals (40 patients with PD and 40 control individuals) participated in this study. Physical activity levels were evaluated through Modified Baecke Questionnaire for Older Adults. Multidimensional Fatigue Inventory (MFI) was used in order to evaluate fatigue dimensions (general, physical and mental fatigue, reduced motivation and activity). MANOVA two-way and Pearson linear correlation test were performed to analyze the data. Results: Patients with PD presented higher levels of fatigue, in all dimensions evaluated by MFI, comparing to control individuals. There was no association between physical activity levels and perception of fatigue for patients with PD and control individuals. Conclusion: Patients with PD showed increased perception of fatigue when compared to control individuals, due to PD characteristics. In addition, the perception of fatigue’s symptom was not influenced and had no relation by the level of physical activity.

The Transport Properties of Concrete under the Simultaneous Coupling of Fatigue Load and Environment Factors

A set of coupling experimental instrument was designed to study the transport properties of chloride ion in concrete under simultaneous coupling action of fatigue load and environmental factors. Firstly the water-saturated performance of modem concrete was investigated, then diffusion performance of chloride ion under different stress levels and different temperature were studied respectively; meanwhile, the time- dependent behavior of the chloride ion diffusion in concrete was also researched. The results showed that the saturation degree of concrete can reach as high as 99%. Besides, diffusion coefficient of chloride ion increased with increasing of the stress level and temperature, and when the stress level and temperature are at 0.6 and 60 ℃ respectively, the diffusion coefficient is 6.3 ×10 -14 m2/s, moreover the diffusion coefficient of chloride ion in concrete decreased with time under the simultaneous coupling action of fatigue load and environment factors.

Empathetic nursing with mindful cognitive therapy for fatigue,depression,and negative emotions in leukemia patients undergoing long-term chemotherapy

BACKGROUND Leukemia is a broad term for blood cell cancer.Leukemia is divided into acute or chronic,depending on cell differentiation.Leukemia patients are prone to adverse reactions during chemotherapy,such as anxiety,depression,and even suicide,affecting prognosis.As a nursing model developed by three well-known cognitive psychologists,empathetic nursing with mindfulness cognitive therapy(ENMCT)can effectively reduce anxiety and depression and improve the quality of life in patients with chronic disease.AIM To explore the effect of ENMCT on cancer-induced fatigue,hope level,and negative emotions in patients with long-term leukemia chemotherapy.METHODS A total of 103 patients with long-term leukemia chemotherapy diagnosed and treated in our hospital from July 2017 to October 2019 were enrolled and randomly assigned to observation and control groups using the random number table approach.Fifty-one patients in the control group received routine nursing,while 52 patients in the observation group received empathic nursing with mindfulness cognitive therapy.After three months of nursing care,cancerinduced fatigue was measured with the Piper Fatigue Scale(PFS),hope level with the Herth Hope Index(HHI),and negative emotion with the Hamilton Anxiety Scale(HAMA)/Hamilton Depression Scale(HAMD).Self-management(Chinese Strategies Used by People to Promote Health)was also recorded.RESULTS The observation group’s total scores in behavior,cognition,emotion,feeling,and PFS were lower than the control group after the intervention(P<0.05).Keeping close contact with others,the attitude of taking positive actions,the attitude toward reality and future,and the total HHI score were higher in the observation group than the control group(P<0.05).The observation group’s HAMA and HAMD scores were lower than the control group(P<0.05).The observation group’s positive attitude,self-decision,and self-relief scores were greater than the control group(P<0.05).CONCLUSION Empathetic nursing with cognitive mindfulness therapy is beneficial in improving cancer-related fatigue,negative emotions,expectation level,and self-management ability in patients with longterm leukemia chemotherapy.

Process Evaluation, Tensile Properties and Fatigue Resistance of Chopped and Continuous Fiber Reinforced Thermoplastic Composites by 3D Printing

The aim of this article was to comprehensively evaluate the manufacturing process,tensile properties and fatigue resistance of the chopped and continuous fiber reinforced thermoplastic composites(CFRTPCs)by 3D printing.The main results included:the common defects of the printed CFRTPCs contained redundant and accumulation defects,scratch and warping defects;the continuous fiber contributed to the dimensional stability and accuracy of width and thickness;associations between mass percentage of fiber reinforcement and the averages of elastic mod-ulus,strain at break and ultimate tensile strength were approximately linear based on tensile test results;the fati-gue resistance improved with the increasing fiber reinforcement based on fatigue test results.As for specimens with four fiber rings,there was a good linear relationship between the stress level and logarithm value of cycles during the whole life while those of pure matrix and specimens with one and two fiber rings were piecewise linear,taking about 10,000 cycles as boundary.The micro morphology showed that the fatigue failure behaved as matrix fracture,large and small fiber bundles and single fibers extracted from matrix.Under the tension-tension fatigue load,the deformations where easily concentrating stress behaved as sunken surfaces along thickness and width directions,and the deformation along width direction was greater than that along thickness direction.

Flexural fatigue strength of steel fibrous concrete containing mixed steel fibres

This paper reports investigation conducted to study the fatigue performance of steel fibre reinforced concrete (SFRC) containing fibres of mixed aspect ratio. An extensive experimental program was conducted in which 90 flexural fatigue tests were carried out at different stress levels on size 500 mm×100 mm×100 mm SFRC specimens respectively containing 1.0%, 1.5% and 2.0% volume fraction of fibres. About 36 static flexural tests were also conducted to determine the static flexural strength prior to fatigue testing. Each volume fraction of fibres incorporated corrugated mixed steel fibres of size 0.6 mm×2.0 mm×25 mm and 0.6 mm×2.0 mm×50 mm in ratio 50:50 by weight. The results are presented both as S-N relationships, with the maximum fatigue stress expressed as a percentage of the strength under static loading, and as relationships between actually applied fatigue stress and number of loading cycles to failure. Two-million-cycle fatigue strengths of SFRC containing different volume fractions of mixed fibres were obtained and compared with plain concrete.

Effect of Fatigue Loading on the Mechanical Properties and Resistance of High-strength Straight-hole Recycled Pervious Concrete to Rainstorm-based Waterlogging

A novel high-strength straight-hole recycled pervious concrete(HSRPC)for the secondary highway pavement was prepared in this paper.This study aimed to investigate the effect of porosity(0.126%,0.502%,and 1.13%),vehicle loading stress level(0.5 and 0.8)and service life on the resistance to rainstormbased waterlogging of HSRPC under fatigue loading.The mechanical properties of HSRPC in terms of flexural strength and dynamic elastic modulus were studied.The waterlogging resistance of HSRPC was described by surface water depth and drainage time.The microstructure of HSRPC were observed with scanning electron microscopy(SEM).Results showed that although the dynamic elastic modulus and flexural strength of HSRPC decreased with the increasing number of fatigue loading,the flexural strength of HSRPC was still greater than5 MPa after design service life of 20 years.After 2.5×10^(5)times of fatigue loading,the permeability coefficient of HSRPC with a porosity of 0.502%and 1.13%increased by 18.4%and 22.9%,respectively;while the permeability coefficient of HSRPC with 0.126%porosity dropped to 0.35 mm/s.The maximum surface water depth of HSRPC with a porosity of 0.126%,0.502%,and 1.13%were 8,5 and 4 mm,respectively.SEM results showed that fatigue loading expanded the number and width of cracks around the tiny pores in HSRPC.

Assessing the Ageing Impact on Fatigue-Life of Asphalt Concrete

The fatigue-life of asphalt concrete is often related to environmental condition,loading condition,ageing,material composition and properties.This work investigates the influence of short and long term ageing of laboratory beam specimens,asphalt percent,and testing temperature on fatigue life of asphalt concrete wearing course.Slab samples of(30 × 40 × 6)cm have been prepared,beam specimens of(40 × 5 × 6)cm were extracted from the asphalt concrete slab samples and tested for fatigue-life under the impact of three levels of micro strain(250,400,and[3]750)at(5,20,and 30)℃ before and after practicing long-term aging.It was observed that the fatigue-life decreased by(85 and 97)%,(87.5 and 97.4)%,(71.4 and 95.2)%after increasing the applied microstrain from(250 to 400 and 750)μƐfor control mixture and for mixtures subjected to shortand long-term ageing processes respectively.The fatigue-life increased by(142.8 and 257.1)%,(34.4 and 57.8)%and(10 and 30)%when the asphalt content increased from(4.4 to 4.9 and 5.4)%for specimens practicing the applied microstrain of(250,400 and 750)μƐrespectively.It can be concluded that the fatigue life increases by a range of(two to fifteen)folds when the testing temperature increases from(5 to 20 and 30)℃ respectively.

Effect of Meridian Massage for Cancer Related Fatigue

Objectives:The purpose of this study is to investigate the effectiveness of meridian massage in lessening the fatigue and improving both physical and mental quality of life of cancer patients.Settings and design:This study was conducted at the East-West Cancer Center at Daejeon University;Using a single-arm,waiting list and non-treatment control research de- sign,we compared the results of control group and to that of the experimental group.Materials and methods:From July 2,2007 to July 28,2007,eighteen eligible cancer patients were recruited to participate in the experiment.Modified Chalder Fatigue Scale(CFS),Visual Analogue Scale(VAS)and active oxygen level were measured before and after treatment for both control and experimental groups.Lying on their back or stomach inside a room with a temperature of 18-22℃,the pa- tients received 30 minutes of meridian massages mainly around the trapezius muscles 5 times a week. Statistical analysis used:Data analysis was carried out using independent t-test,paired t-test and One-way ANOVA. Results:Data analysis of modified CFS showed statistically significant results for all groups between before and after treat- ment.Within CFS,results of physical and psychological analysis showed significant results for all groups except before and after no treatment and secondary treatment.In the analysis of VAS,the experimental group showed a greater decrease in score compared to that of the control group and the average difference was statistically significant(P<0.05).Although the results were not statistically significant(P>0.05),active oxygen levels for the control group showed little difference before and after no treatment(331.11 and 330.78,respectively)while the experimental group observed a decrease in active oxygen level before and after treatment(327.28 and 314.11,respectively).Conclusion:In conclusion,patients who received meridian massage showed decreased cancer related fatigue scores compared to the control.These results suggest that meridian massage may alleviate cancer-related fatigue and contribute to the improvement in quality of life among cancer patients.

分阶段护理在达芬奇机器人辅助肺癌根治术患者中的应用

目的分析基于德尔菲法的分阶段护理在达芬奇机器人辅助肺癌根治术患者中的应用效果。方法选取医院2021年5月至2022年10月收治的87例肺癌患者,均在全麻下接受达芬奇机器人辅助肺癌根治术治疗,依照随机数字表法分为两组,对照组(43例)接受常规护理干预,观察组(44例)在对照组基础上接受基于德尔菲法指导的分阶段护理,比较两组干预前后心理应激反应、生理应激反应、癌因性疲乏程度、生活质量。结果术前30 min,两组14项汉密尔顿焦虑量表(HAMA)、17项汉密尔顿抑郁量表(HAMD)评分均降低,且观察组低于对照组(P<0.05);术前30 min,两组心率、收缩压、舒张压水平均升高,但观察组较对照组低(P<0.05);干预后,观察组Piper疲乏量表(PFS)评分低于对照组,肺癌患者生存质量测定量表(FACT-L)评分高于对照组(P<0.05)。结论基于德尔菲法指导的分阶段护理应用于全麻下达芬奇机器人辅助肺癌根治术患者,能有效减少心理、生理应激,缓解癌因性疲乏程度,提高生活质量。

针对性干预对肺癌化疗伴癌因性疲乏患者的影响

目的:探讨针对性干预对肺癌化疗伴癌因性疲乏患者的影响。方法:选择2021年3月—2023年3月江西省肿瘤医院胸内一病区接收的肺癌化疗伴癌因性疲乏患者80例作为研究对象,按随机数字表法将其分为对照组与观察组,各40例。对照组给予常规干预措施,观察组在对照组的基础上给予针对性干预,比较两组癌因性疲乏程度、心理状态、社会适应性、希望水平、睡眠质量、生存质量。结果:干预后观察组癌因性疲乏程度轻于对照组,差异有统计学意义(P<0.05)。干预后观察组焦虑自评量表(SAS)、抑郁自评量表(SDS)评分均低于对照组,差异均有统计学意义(P<0.05)。干预后观察组社会适应性量表的心理弹性、心理能量、人际适应性、控制倾向维度评分均高于对照组,差异均有统计学意义(P<0.05)。干预后,观察组希望水平、生存质量评分均高于对照组,睡眠质量评分低于对照组,差异均有统计学意义(P<0.05)。结论:对肺癌化疗伴癌因性疲乏患者实施针对性干预可进一步疏解负面情绪,改善癌因性疲乏症状,并增强患者的社会适应性,提高希望水平,恢复良好的睡眠质量和生存质量。

家属协同心理认知护理在乳腺癌切除术患者中的应用

目的探讨家属协同心理认知护理对乳腺癌切除术患者痛苦程度及积极应对方式的影响。方法采用前瞻性研究,选取西安市中心医院在2022年2月至2023年2月期间收治的81例乳腺癌切除术患者作为研究对象,通过随机数字表法分为对照组(40例)和观察组(41例)。对照组采用常规护理,年龄(53.28±4.51)岁,肿瘤分期:Ⅰ期22例,Ⅱ期16例,Ⅲ期2例;观察组采用家属协同心理认知护理,年龄(53.34±4.47)岁,肿瘤分期:Ⅰ期23例,Ⅱ期14例,Ⅲ期4例。比较两组患者干预前及干预3个月后痛苦程度、积极应对方式[采用应对方式问卷(CSQ)]、癌因性疲乏[采用癌症疲乏量表(CFS)]及自护能力[自我护理能力测定量表(ESCA)],统计学方法采用t检验、χ^(2)检验。结果干预3个月后,观察组的体力、宗教、情感、家庭、实际心理痛苦程度分别为(3.51±0.66)分、(3.14±0.71)分、(3.97±0.65)分、(3.52±0.88)分、(4.33±1.00)分,均低于对照组[(4.92±0.89)分、(4.22±0.90)分、(5.38±0.95)分、(5.07±1.23)分、(5.62±0.93)分],观察组DT评分为(3.54±0.57)分,低于对照组(4.60±0.75)分,两组比较差异均有统计学意义(均P<0.05);观察组CSQ评分中自责、幻想、退避评分分别为(0.41±0.06)分、(0.52±0.08)分、(0.43±0.04)分,均低于对照组[(0.62±0.09)分、(0.69±0.03)分、(0.62±0.06)分],求助、解决问题、合理化等维度评分分别为(0.69±0.06)分、(0.63±0.06)分、(0.69±0.07)分,均高于对照组[(0.48±0.05)分、(0.49±0.05)分、(0.56±0.05)分],两组比较差异均有统计学意义(均P<0.05);观察组CFS评分中躯体疲劳、认知疲劳、情感疲劳维度评分分别为(15.37±1.84)分、(9.66±1.43)分、(8.02±1.23)分,均低于对照组[(22.61±2.41)分、(13.10±1.51)分、(12.97±1.64)分],两组比较差异均有统计学意义(均P<0.05);观察组ESCA评分中健康知识、自护技能、自我概念、自我责任维度分别为(49.58±4.40)分、(41.85±3.80)分、(30.29±3.38)分、(27.30±2.29)分,均高于对照组[(42.35±4.83)分、(37.06±3.11)分、(27.16±3.88)分、(24.11±2.04)分],两组比较差异均有统计学意义(均P<0.05)。结论对乳腺癌切除术患者给予家属协同心理认知护理,能够有效降低其痛苦程度及癌因性疲乏,提高积极应对方式及自护能力。

癌因性疲乏的中医证候特征及其与甲状腺功能水平的相关性研究

背景 中西医结合下的多学科参与是癌因性疲乏(CRF)未来诊疗模式的发展方向。然而,缺乏辨证选方的标准和依据限制了中医药在西医和国际范围内的应用。CRF患者的疲乏感常伴随着代谢和能量平衡的异常,甲状腺功能在机体能量代谢和调节方面扮演着重要角色。目的 分析CRF的中医证候特征并探讨其与甲状腺功能水平之间的相关性,为CRF的中西医结合诊疗和机制研究提供参考。方法 纳入2021年就诊于中国中医科学院西苑医院肿瘤科门诊及病房的肿瘤患者为研究对象,收集患者一般资料。采用中文版Piper疲乏修订量表(RPFS-CV)评估患者疲乏情况。收集入组患者当日或次日的甲状腺功能检测结果,包括三碘甲状腺原氨酸(T_(3))、甲状腺素(T_(4))、游离三碘甲状腺原氨酸(FT_(3))、游离甲状腺素(FT_(4))、促甲状腺激素、抗甲状腺过氧化物酶抗体(TPO-Ab)、甲状腺球蛋白抗体。由自拟CRF中医四诊信息表收集CRF患者中医证候特征。采用Spearman秩相关分析探讨RPFS-CV疲乏评分与甲状腺功能指标的相关性,采用点二列相关分析探讨RPFS-CV疲乏评分和甲状腺功能指标与CRF中医证候的相关性。结果 纳入159例CRF患者,常见的肿瘤种类依次为肺癌(50例,31.4%)、乳腺癌(23例,14.5%)、头颈部肿瘤(21例,13.2%)、直肠癌(21例,13.2%)、结肠癌(18例,11.3%);中位确诊年限为2.15(3.16)年;88例(55.3%)患者发生了复发转移,40例(45.5%)患者为局部复发,38例(43.2%)患者为寡转移,中位转移年限为1.50(2.83)年;91例(57.2%)为晚期患者,101例(63.5%)患者接受过抗肿瘤治疗,57例(35.8%)患者接受化疗。中医证候中,虚证频率超过10%从高到低分别为气虚证、心虚证、脾虚证;实证中出现频次超过20次的从高到低分别为气滞证、寒湿证。RPFS-CV疲乏评分中位数超过4分的证候从高到低分别为寒湿证、气滞证、脾虚证、心虚证、肝虚证、湿热证、气虚证。RPFS-CV疲乏评分与气虚证、脾虚证、心虚证、肝虚证、寒湿证、气滞证呈正相关(P<0.05)。RPFS-CV疲乏评分与FT_(3)、T_(3)呈负相关(P<0.05)。气虚证与T_(4)、肾虚证与TPO-Ab、气滞证与FT_(4)呈正相关(P<0.05),湿热证与T_(3)、T_(4)呈负相关(P<0.05)。结论 CRF患者疲乏情况与中医证候及甲状腺功能水平密切相关,进一步的研究将有助于深入理解这些关联,并促进中医和西医在CRF疾病管理中的协同发展。

考虑员工疲劳度和休假的退化系统可靠性建模与检测策略研究

在退化系统检测维修策略的研究中,很少考虑人为因素对检测正确率的影响。事实上,考虑员工疲劳度水平和其工作状态可以更精确地评估和优化维修检测策略,帮助企业降低运维成本。本文考虑维修工的工作状态对检测结果的影响,通过建立疲劳度和检测正确率的函数关系,构建检测维修模型,以最小化维修成本为目标,优化员工工作时间安排、休假时间安排以及检测时间间隔;最后进行算例分析,针对各成本参数做敏感度分析,讨论参数变化时最优休假策略和维修策略的变化规律,从而寻找更广泛的优化适用性。结果表明检测出错成本大的系统,决策者应提高员工休假时间,降低检测频率;预防性维修成本高的系统,决策者应适当提高员工在岗时间并降低检测频率;停机机会成本更高的系统应提高员工在岗时间,同时提高检测频率。

护士自我调节疲劳现状及与医院磁性水平的关系研究

目的了解护士自我调节疲劳现状及感知医院磁性水平,探讨医院磁性水平对护士自我调节疲劳的影响,为制定干预措施提供参考。方法2023年5-8月,采用一般资料调查表、医院磁性要素量表、自我调节疲劳量表对西安市2所三级甲等医院的825名临床护士开展调查。结果护士自我调节疲劳总分(48.22±6.62)分,感知医院磁性水平总分(103.44±14.84)分。医院磁性水平与护士自我调节疲劳呈负相关;医院磁性水平、聘用类型、每月收入、夜班频次是护士自我调节疲劳的主要影响因素(均P<0.05),医院磁性水平可解释护士自我调节疲劳16.00%的总变异。结论护士自我调节疲劳及感知医院磁性水平均处于中等水平,医院磁性水平是护士自我调节疲劳的重要影响因素。管理者可以通过改善医院磁性水平以降低护士自我调节疲劳水平。

分析人性化干预对改善产妇产后睡眠质量及疲乏程度效果

目的:浅析人性化干预对产妇产后睡眠质量及疲乏程度的影响。方法:选取2022年1月至2023年1月厦门大学附属第一医院接诊的产妇42例作为研究对象,按照随机数字表法分为对照组(n=20)和观察组(n=22),对照组给予常规产后护理干预,观察组给予人性化护理干预。采用阿森斯失眠量表(AIS)与自我睡眠评估比较2组产妇干预前后睡眠质量的变化,采用疲劳评定量表(FAI)比较2组产妇干预前后疲劳程度。结果:干预后,观察组阿森斯失眠量表AIS评分、FAI评分均显著低于对照组,差异有统计学意义(P<0.05)。结论:采取人性化护理干预可以有效提高产妇产后的睡眠质量,减轻身体的疲乏程度,对产后康复起到良好的促进作用,具有临床推广应用价值。

县域医院护士共情疲劳与职业获益感的关系研究

目的描述县域医院护士共情疲劳的现状,探索与职业获益感及其他因素关系。方法采用便利抽样法选择2022年9—10月福建省泉州市南安市2所二级甲等综合医院112名护士,使用护士职业获益感问卷、共情疲劳问卷调查其职业获益感、共情疲劳情况。结果县域医院护士职业获益感总分为(132.29±16.29)分,重度共情疲劳占64.3%。县域医院护士共情疲劳主要受护龄、学历、亲友认同、正向职业认知等因素影响。结论县域医院护士共情疲劳问题突出,存在较高比例的重度共情疲劳,但职业获益感处于中等偏上水平。护理管理者应积极采取措施缓解护士共情疲劳情况,尤其是针对共情满意、职业倦怠、继发性创伤应激表现不佳的护士。

二胎产妇产褥期疲乏现状及影响因素分析

目的:分析二胎产妇产褥期疲乏现状及影响因素。方法:通过横断面研究,采用便利抽样法,选取2023年1月—11月某医院产科收治的290例二胎产妇为研究对象。采用一般资料调查表、疲乏量表、Wong-Baker面部表情量表、爱丁堡产后抑郁量表和匹兹堡睡眠质量指数(PSQI)分析二胎产妇产褥期疲乏的影响因素。结果:290例二胎产妇产褥期疲乏得分为(8.17±2.36)分,其中,有275例二胎产妇产褥期得分≥3分,二胎产妇产褥期疲乏的发生率为94.82%。单因素分析结果显示,不同分娩方式、喂养方式、产褥期并发症、近1周夜间醒来次数的二胎产妇产褥期疲乏得分比较差异均有统计学意义(P<0.05),Pearson相关性分析结果显示,290例二胎产妇产褥期疲乏程度与疼痛程度、产后抑郁水平和PSQI得分均呈正相关(r值分别为0.428,0.453,0.549,均P<0.001)。多元线性回归分析结果显示,分娩方式、近1周夜间醒来次数、疼痛程度、产后抑郁水平、睡眠质量是二胎产妇产褥期疲乏的主要影响因素(均P<0.05),变量共同解释了二胎产妇产褥期疲乏总变异的51.8%。结论:二胎产妇产褥期疲乏普遍存在,且处于中等偏高水平,提示医护人员应重点关注剖宫产、夜间醒来次数多、疼痛程度明显、存在产后抑郁和睡眠质量差的产妇,定期为二胎产妇开展孕期健康教育讲座,讲解孕期生理变化、育儿照护措施、疼痛管理、心理健康和睡眠管理等方面的知识,帮助其更好地应对孕期的各种问题,以减轻疲乏。

基于台架试验数据的铸件疲劳寿命分析与应用

以商用车铸造后桥壳为研究对象,对多个类型桥壳台架试验疲劳寿命进行数据分析处理,得到失效时的加载循环次数。应用基于时间历程载荷的有限元疲劳分析方法,得到铸造桥壳在对应载荷循环下的疲劳等效应力,联合疲劳等效应力与失效次数获得铸造桥壳的S-N曲线。结果表明,当前分析的铸造桥壳存在缺陷控制水平低的问题,需要提升制造工艺水平,并提出在设计中制定缺陷等级分类的重要性。应用有限元疲劳分析联合试验数据,可以在工艺水平稳定的前提下,提前有效预测新设计结构的疲劳寿命,将有限元分析结果与制造工艺联系起来,扩展了试验数据的实用性。