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简介：摘要高性能混凝土是一种新型高技术混凝土，大都是通过降低水胶比、掺加矿物掺合料来提高混凝土中水泥石的密实度，改善混凝土界面薄弱区结构形态，从而达到高性能目的。一般来讲，与普通混凝土相比，其早期自收缩、温度收缩、干燥收缩大、弹性模量高、徐变能力小；当混凝土收缩受到约束时，会引发很大的自应力。所以，高性能混凝土有着比普通混凝土更大的开裂趋势。本文分析了高性能混凝土原料和配备的抗裂性，介绍了高性能混凝土自收缩、内部湿度的理论研究现状,同时提出了相应的发展方向。

简介：摘要：高性能混凝土是一种具有高强度、高耐久性与高工作性的混凝土,混凝土中的水泥石只有凝胶孔无毛细孔,具有高的抗渗性和耐久性。HPC组成材料中必须具有矿物质超细粉和高效减水剂。本文介绍了高性能混凝土材料的配合比特点、影响高性能混凝土的因素。

简介：摘要：在实际应用过程中，混凝土收缩裂缝的出现往往与其在凝固过程中的水化放热情况之间存在着直接的联系，本文主要以某大坝工程为例，介绍了在工程项目施工过程中，控制高性能混凝土的流动性与收缩性，可以有效提升工程项目的整体质量，希望能够给当前高性能混凝土的使用带来启发。

简介：去年八月,ATI发布了R300内核的Radeon9700系列,它打败了当时的GeForce4Ti4600,从而一举成为PC显卡领域的性能之王,不过随着nVIDIAGeForceFX(5800和5800Ultra)的发布,性能之王的宝座再度易主,但在和Radeon9700Pro的较量中,GeForceFX并未占有压倒性的优势,ATI自然不愿意看着性能之王的称

简介：AbstractObjective:This survey was designed to understand the misconceptions about labor epidurals.Methods:This voluntary and anonymous online survey on wenjuan.com was conducted from September 1st, 2015 to January 1st, 2016 via mainly WeChat groups dedicated to perinatal healthcare providers in China. The questionnaire included items inquiring the knowledge and opinions about labor epidural analgesia related to maternal complications, baby safety, and effect on laboring. Incomplete surveys were excluded from the data analysis. The data was presented as percentages and a Chi-square test or Fisher’s exact test, as appreciate, was used to quantitatively compare the results.Results:A total of 1412 respondents completed surveys with 42.9% (606/1412) of them being anesthesiologists, 35.1% (495/1412) being obstetricians, 11.8% (167/1412) being midwives, 3.7% (52/1412) being labor and delivery nurses, and 6.5% (92/1412) being hospital administrators and unspecified. The study revealed a lack of knowledge in labor pain control. Although 82.4% (1164/1412) of respondents were familiar with labor epidural analgesia, 8.9% (126/1412) did not know how it works, and 1.1% (15/1412) never heard it in a multiple-choice question. The three main groups (anesthesiologists, obstetricians, and midwives/labor and delivery nurses) were chosen for comparisons. Opinions among these three groups concerning five questions in the three main concerns were evaluated using a statistical significance of P<0.05.Conclusion:The results in our survey indicated an urgent need of continuing medical education to multidisciplinary specialties to improve evidence-based medical practices as these misconceptions have existed for over 10 years in the medical professionals. Lack of public awareness fueled by misconceptions related to labor epidural analgesia may be associated with a lack of professional knowledge. Correct knowledge in professionals needs to be disseminated to the public in order to dispel possible misconceptions and rumors about labor epidural analgesia. This would not only enhance patient understanding of their care but also improve maternal, fetal, and neonatal outcomes.

简介：AbstractBackground:Zoonoses are public health threats that cause severe damage worldwide. Zoonoses constitute a key indicator of One Health (OH) and the OH approach is being applied for zoonosis control programmes of zoonotic diseases. In a very recent study, we developed an evaluation system for OH performance through the global OH index (GOHI). This study applied the GOHI to evaluate OH performance for zoonoses in sub-Saharan Africa.Methods:The framework for the OH index on zoonoses (OHIZ) was constructed including five indicators, 15 subindicators and 28 datasets. Publicly available data were referenced to generate the OHIZ database which included both qualitative and quantitative indicators for all sub-Sahara African countries (n = 48). The GOHI algorithm was used to estimate scores for OHIZ. Indicator weights were calculated by adopting the fuzzy analytical hierarchy process.Results:Overall, five indicators associated with weights were generated as follows: source of infection (23.70%), route of transmission (25.31%), targeted population (19.09%), capacity building (16.77%), and outcomes/case studies (15.13%). Following the indicators, a total of 37 sub-Sahara African countries aligned with OHIZ validation, while 11 territories were excluded for unfit or missing data. The OHIZ average score of sub-Saharan Africa was estimated at 53.67/100. The highest score was 71.99 from South Africa, while the lowest score was 40.51 from Benin. It is also worth mentioning that Sub-Sahara African countries had high performance in many subindicators associated with zoonoses, e.g., surveillance and response, vector and reservoir interventions, and natural protected areas, which suggests that this region had a certain capacity in control and prevention or responses to zoonotic events.Conclusions:This study reveals that it is possible to perform OH evaluation for zoonoses in sub-Saharan Africa by OHIZ. Findings from this study provide preliminary research information in advancing knowledge of the evidenced risks to strengthen strategies for effective control of zoonoses and to support the prevention of zoonotic events.

简介：摘要在最近几年来，随着科技的猛速发展，一种新型的混凝土逐渐运用的工程中，这对提高工程质量和工程的寿命起的不可估计的作用，那就是高性能混凝土，高性能混凝土具有高耐久性，高工作性，高强度，高体积稳定性等多方面的优越性，。特别是在道路桥梁中，高层建筑中被广泛的应用。本文就对高性能混凝土的性质及其组成进行简单的探讨。

简介：摘要随着时代的变化，经济的快速发展，现今的混凝土问题中，较普遍的问题就是裂缝，但混凝土的裂缝指标很难做到量化控制，而且产生因素复杂多样，其分析工作一直是技术人员难以攻克的问题之一。当今应用最广泛的一种混凝土是高性能混凝土，这种混凝土较好地满足了人们的需求，也为技术人员的研究工作提供了很大帮助。

简介：摘要：本文首先介绍高性能混凝土与传统混凝土的本质区别，重点突出高性能混凝土的优势及实用性；其次，梳理高性能混凝土在发展中存在的问题并阐明原因；最后，结合高性能混凝土的性能特点探索其工程应用价值，并就其未来发展做出展望。本文在众多文献调研的基础上,总结归纳国内外现有研究成果，探讨高性能混凝土的性能、面临的问题及应用前景，是一篇有关高性能混凝土特性及应用的综述型论文，为后续相关领域发展及研究提供一定的参考价值。

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简介：摘要：本文深入探讨了救生圈检验检测的重要性、标准、流程以及面临的挑战。通过分析救生圈的材料、结构、性能等方面的检测，本文旨在提出改进策略，以确保救生圈在紧急情况下的有效性，从而保护人们的生命安全。

简介：摘要经济在快速的发展，社会在不断的进步，该文研究了消泡剂的使用、细骨料颗粒级配、硅灰种类及砂胶比等因素对超高性能混凝土（UHPC）拌合物流动度、含气量以及硬化UHPC抗压强度和抗折强度的影响。研究结果表明，当水灰比较大时，消泡剂的使用可明显降低含气量，使得UHPC抗压强度和抗折强度明显增大。硅灰加密状态对制备的UHPC流动度和力学性能影响显著，未加密硅灰制备的UHPC力学性能最优，而半加密硅灰制备的UHPC流动度最大。砂胶比在0.8～1.2范围内增大会降低UHPC拌合物流动度，但抗折强度增长显著。

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简介：摘要：高性能混凝土的主要特点是高减水剂新拌混凝土的高工作性、活性细掺合料、低水灰比、硬化后细观结构紧凑。因此，特别适用于高层、大跨度等现代建筑工程和桥梁结构。它的广泛应用取得了显著的技术、经济和社会效益。高性能混凝土不仅表现出优异的性能，也暴露出其不足。

简介：摘要：随着城市化进程的加速，建筑物的数量和高度不断增加。火灾是建筑物中最为严重的安全事故之一，长时间高温作用和持续燃烧会导致建筑物的完整性损伤和承载能力下降，可能导致坍塌和二次伤害。因此，利用现代科技来防范、救助、阻止大型火灾的发生，加强灾难发生后的紧急处理方案的研究非常必要。我国在建筑材料高温性能方面的研究起步较晚，但近年来已加大研究扶持力度。本文研究高温对高性能混凝土性能的影响，采用电阻炉加热试件模拟高温下高性能混凝土的动态冲击试验，并对其损伤比进行分析。研究结果表明，随着温度的升高，高性能混凝土的损伤比逐渐增加，且不同强度等级的高性能混凝土在高温下的表现也存在差异。

简介：摘要：现代建筑高楼耸立，电梯是必备设备之一，人们在享受电梯带来的各种便利的同时也存在着一系列的安全隐患。因此，在电梯的使用过程中需要有专业人员进行检测和性能分析，为更好的使用电梯做基础保障。本文从电梯安全性能影响因素及性能检测出发，客观分析因果并提出相关措施。

简介：摘要： 在新科学技术的影响下，高速动车组也在进行全面提升发展，高速动车的车体结构的材料也进行更新换代，传统的钢材质的车体结构已经开始逐渐被铝合金材质的车体进行淘汰，铝合金材质的车体结构比钢材质的车体更加轻盈，采用新材料能够使高速动车组的车体实现轻量化，但同时还能保障高速动车的行程安全，新材料就需要新的焊接技术，基于此对铝合金焊接技术和性能以及焊接接头的性能成为本文探究的内容。

简介：超高性能混凝土的配合比能够直接决定超高性能混凝土的工作性能和抗压强度，基于实际研究蒸养超高性能混凝土配合比参数对混凝土性能影响意义重大。本文基于蒸汽养护超高性能混凝土胶砂比、水胶比、钢纤维掺量、减水剂掺加量等参数展开对混凝土坍落度扩展度和抗压强度影响程度的研究，意在寻找最佳配合比参数，并针对超高性能混凝土的应用展开研究。