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混凝土 17

三峡工程 7

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Damage on lining concrete in highway tunnels under combined sulfate and chloride attack

Rongrong YIN, Chenchen ZHANG, Qing WU, Baocheng LI, He XIE

《结构与土木工程前沿（英文）》 2018年第12卷第3期页码 331-340 doi: 10.1007/s11709-017-0421-y

摘要：

The combined effect from sulfate and chloride is one of the important reasons to cause the damage of lining concrete in highway tunnels. To investigate the effect of chloride ions on the corrosion of lining concretes under sulfate attack, ultrasonic detecting, compression test and X-ray Diffraction (XRD) were performed on the concretes to obtain the ultrasonic velocity, corrosion thickness, compression strength and corrosion products. The ultrasonic results, compression strength and XRD patterns confirmed that the existence of chloride certainly depressed the corrosion damage on the lining concretes under sulfate attack, and the depressing effect increased with the content of chloride in the composite solution. The corrosion damage on the concretes experienced three stages independent of the composition of corrosive solution: initial slower enhancement on the strength, stabilization period and linear degradation period. The existence of chloride mainly affected the final degradation stage and obviously decreased the corrosion thickness.

关键词： lining concrete sulfate chloride compression ultrasonic

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Deep convolutional neural network for multi-level non-invasive tunnel lining assessment

《结构与土木工程前沿（英文）》 2022年第16卷第2期页码 214-223 doi: 10.1007/s11709-021-0800-2

摘要： In recent years, great attention has focused on the development of automated procedures for infrastructures control. Many efforts have aimed at greater speed and reliability compared to traditional methods of assessing structural conditions. The paper proposes a multi-level strategy, designed and implemented on the basis of periodic structural monitoring oriented to a cost- and time-efficient tunnel control plan. Such strategy leverages the high capacity of convolutional neural networks to identify and classify potential critical situations. In a supervised learning framework, Ground Penetrating Radar (GPR) profiles and the revealed structural phenomena have been used as input and output to train and test such networks. Image-based analysis and integrative investigations involving video-endoscopy, core drilling, jacking and pull-out testing have been exploited to define the structural conditions linked to GPR profiles and to create the database. The degree of detail and accuracy achieved in identifying a structural condition is high. As a result, this strategy appears of value to infrastructure managers who need to reduce the amount and invasiveness of testing, and thus also to reduce the time and costs associated with inspections made by highly specialized technicians.

关键词： concrete structure GPR damage classification convolutional neural network transfer learning

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高强钢筋混凝土预制弧板井壁力学特性分析

荣传新,王秀喜,程桦

《中国工程科学》 2005年第7卷第7期页码 43-49

摘要：

对高强钢筋混凝土预制弧板井壁结构的研究表明，实验结果与数值计算结果基本一致。高强钢筋混凝土预制弧板井壁结构具有很高的承载能力，影响其承载能力的主要因素依次为混凝土的强度等级、厚径比和配筋率。在均布荷载作用下，混凝土的强度等级提高10MPa，极限承载力提高1.26MPa。厚径比每增加1%，极限承载力增加0.85 MPa。增大配筋率对提高其极限承载力作用不大，配筋率增大3倍，极限承载力只增加了0.1MPa。

关键词：高强钢筋混凝土预制弧板井壁力学特性有限元法 ANSYS

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施工与运营初期厚表土立井井壁受力实测研究

温德华

《中国工程科学》 2012年第14卷第2期页码 80-84

摘要：

采用井筒内外井壁现场埋设传感器的方法，建立由计算机控制的自动监测系统，实测大屯矿区某混合井井壁施工过程及之后一段时间的受力和变形演变规律。对实测结果进行分析，研究内外井壁的综合变形规律，可以预测井壁的长期安全性，为井壁破裂的预防和治理提供科学决策的依据。

关键词：井壁监测厚表土应变附加力

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Application of coupled XFEM-BCQO in the structural optimization of a circular tunnel lining subjected

Nazim Abdul NARIMAN, Ayad Mohammad RAMADAN, Ilham Ibrahim MOHAMMAD

《结构与土木工程前沿（英文）》 2019年第13卷第6期页码 1495-1509 doi: 10.1007/s11709-019-0574-y

摘要： A new structural optimization method of coupled extended finite element method and bound constrained quadratic optimization method (XFEM-BCQO) is adopted to quantify the optimum values of four design parameters for a circular tunnel lining when it is subjected to earthquakes. The parameters are: tunnel lining thickness, tunnel diameter, tunnel lining concrete modulus of elasticity and tunnel lining concrete density. Monte-Carlo sampling method is dedicated to construct the meta models so that to be used for the BCQO method using matlab codes. Numerical simulations of the tensile damage in the tunnel lining due to a real earthquake in the literature are created for three design cases. XFEM approach is used to show the cracks for the mentioned design cases. The results of the BCQO method for the maximum design case for the tunnel tensile damage was matching the results obtained from XFEM approach to a fair extent. The new coupled approach manifested a significant capability to predict the cracks and spalling of the tunnel lining concrete under the effects of dynamic earthquakes.

关键词： ovaling deformation monte carlo sampling XFEM-BCQO maximum principal stress

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Digital microfluidics: A promising technique for biochemical applications

He WANG, Liguo CHEN, Lining SUN

《机械工程前沿（英文）》 2017年第12卷第4期页码 510-525 doi: 10.1007/s11465-017-0460-z

摘要：

Digital microfluidics (DMF) is a versatile microfluidics technology that has significant application potential in the areas of automation and miniaturization. In DMF, discrete droplets containing samples and reagents are controlled to implement a series of operations via electrowetting-on-dielectric. This process works by applying electrical potentials to an array of electrodes coated with a hydrophobic dielectric layer. Unlike microchannels, DMF facilitates precise control over multiple reaction processes without using complex pump, microvalve, and tubing networks. DMF also presents other distinct features, such as portability, less sample consumption, shorter chemical reaction time, flexibility, and easier combination with other technology types. Due to its unique advantages, DMF has been applied to a broad range of fields (e.g., chemistry, biology, medicine, and environment). This study reviews the basic principles of droplet actuation, configuration design, and fabrication of the DMF device, as well as discusses the latest progress in DMF from the biochemistry perspective.

关键词： digital microfluidics electrowetting on dielectric discrete droplet biochemistry

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室内装饰材料的标准房间/墙角火实验研究进展

杨昀,张和平,刘激扬

《中国工程科学》 2003年第5卷第4期页码 55-60

摘要：

标准房间/墙角火实验是一种全尺度火灾实验研究方法，主要用来研究室内装饰材料的火灾特性。介绍了ISO 9705房间/墙角火实验方法的原理和实验装置，以及国内外利用该方法对装饰材料火灾特性进行研究的进展情况，包括对材料热释放速率、烟气产生和室内火蔓延方面的研究。分析了其研究成果在室内装饰材料的分类及火灾危险性评估中的实际应用情况，并结合作者目前的工作对未来的研究内容做了一些展望。

关键词：装饰材料全尺度 ISO 9705 房间/墙角火实验

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Fludarabine and intravenous busulfan conditioning with post-transplantation cyclophosphamide for allogeneic peripheral stem cell transplantation for adult patients with lymphoid malignancies: a prospective single-arm phase II study

Ling Wang, Lining Wang, Xing Fan, Wei Tang, Jiong Hu

《医学前沿（英文）》 2021年第15卷第1期页码 108-115 doi: 10.1007/s11684-019-0730-8

摘要： Post-transplantation cyclophosphamide (PT-Cy) alone or in combination with other immunosuppressive drugs has emerged as a promising strategy in the setting of allogeneic hematopoietic stem cell transplantation. Improved survival rate was reported in lymphoid malignancies following PT-Cy strategy compared with myeloid disease in non-myeloablative bone marrow transplant setting. Thus, we aimed to evaluate the safety and efficacy of PT-Cy combined with cyclosporine as graft-versus-host disease (GVHD) prophylaxis after myeloablative conditioning and T cell-replete peripheral stem cell transplantation in lymphoid malignancies. This single-arm phase II clinical trial (NCT01435447) involving 31 adult patients was conducted from January 2013 to June 2018. The donor-type neutrophil engraftment rate was 100%, and the overall incidence of grade II to IV and grade III to IV acute GVHD was 39% and 24%, respectively. The cumulative incidence rates of chronic GVHD (35%), including moderate to severe forms (10%), were reduced compared with those of the historical group ( =0.03 and =0.04, respectively). With a median follow-up of 18 months, the estimated 2-year overall and event-free survival was 64.8% (95% confidence interval: 47.8%–86.7%) and 58.4% (95% CI: 41.9%–81.7%), respectively. The 2-year cumulative incidence rate of relapse was 19.5% (95% CI: 9.0%–35.8%), whereas the non-relapse mortality rate was 21.8% (95% CI: 11.3%–38.1%). These results demonstrated the feasibility of PT-Cy as GVHD prophylaxis in this clinical setting. This strategy could significantly reduce the incidence of chronic GVHD and its moderate to severe forms but not of acute GVHD and results in similar survival outcomes compared with the historical group. A prospective study with additional patients is warranted to confirm the role of PT-Cy in lymphoid malignancy.

关键词： post-transplantation cyclophosphamide allogeneic hematopoietic stem cell transplantation lymphoid malignancies

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水下盾构法铁路隧道管片衬砌结构的原型加载试验研究

何川,封坤,晏启祥,齐春

《中国工程科学》 2012年第14卷第10期页码 65-72

摘要：

针对我国第一条水下铁路盾构法隧道——狮子洋隧道，采用“多功能盾构隧道结构体试验系统”装置原型管片衬砌结构，在通缝和错缝不同的拼装方式下进行了原型结构加载试验，对其结构力学性能进行深入探讨。试验结果表明，不同水压条件下管片衬砌结构力学特征不同，尤其是当结构开裂后，高水压对于结构内力与形变的发展有明显的减缓作用。狮子洋隧道采用的榫式接头管片结构在通缝与错缝拼装下的破坏特征不同，通缝拼装时结构在高水压条件下纵缝附近区域易发生局部剪切破坏，该研究成果可为同类工程的设计提供有价值的参考。

关键词：水下盾构法铁路隧道管片衬砌结构原型试验榫式接头破坏特征

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Zinc homeostasis in the metabolic syndrome and diabetes

null

《医学前沿（英文）》 2013年第7卷第1期页码 31-52 doi: 10.1007/s11684-013-0251-9

摘要：

Zinc (Zn) is an essential mineral that is required for various cellular functions. Zn dyshomeostasis always is related to certain disorders such as metabolic syndrome, diabetes and diabetic complications. The associations of Zn with metabolic syndrome, diabetes and diabetic complications, thus, stem from the multiple roles of Zn: (1) a constructive component of many important enzymes or proteins, (2) a requirement for insulin storage and secretion, (3) a direct or indirect antioxidant action, and (4) an insulin-like action. However, whether there is a clear cause-and-effect relationship of Zn with metabolic syndrome, diabetes, or diabetic complications remains unclear. In fact, it is known that Zn deficiency is a common phenomenon in diabetic patients. Chronic low intake of Zn was associated with the increased risk of diabetes and diabetes also impairs Zn metabolism. Theoretically Zn supplementation should prevent the metabolic syndrome, diabetes, and diabetic complications; however, limited available data are not always supportive of the above notion. Therefore, this review has tried to summarize these pieces of available information, possible mechanisms by which Zn prevents the metabolic syndrome, diabetes, and diabetic complications. In the final part, what are the current issues for Zn supplementation were also discussed.

关键词： zinc zinc transporters metallothionein diabetes diabetic complications insulin resistance antioxidant

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中国铝工业应用新型电极材料的研究与展望

邱竹贤

《中国工程科学》 2001年第3卷第5期页码 50-54

摘要：

介绍了现代铝工业上新近开发研制的几种电极材料，涉及惰性阴极、惰性阳极、双极性电极等；还研制了低温电解质，使电解温度降低到800～900℃。如果惰性电极与低温电解质配合起来应用，则能够明显减少工业铝生产中的物料消耗，节省电能，增大电解槽生产能力，并改善环境状况，可望大幅度降低生产成本。

关键词：惰性阳极惰性阴极 SiC绝缘侧壁低温铝电解

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Slender reinforced concrete shear walls with high-strength concrete boundary elements

《结构与土木工程前沿（英文）》 2023年第17卷第1期页码 138-151 doi: 10.1007/s11709-022-0897-y

摘要： Reinforced concrete structural walls are commonly used for resisting lateral forces in buildings. Owing to the advancements in the field of concrete materials over the past few decades, concrete mixes of high compressive strength, commonly referred to as high-strength concrete (HSC), have been developed. In this study, the effects of strategic placement of HSC on the performance of slender walls were examined. The finite-element model of a conventional normal-strength concrete (NSC) prototype wall was validated using test data available in extant studies. HSC was incorporated in the boundary elements of the wall to compare its performance with that of the conventional wall at different axial loads. Potential reductions in the reinforcement area and size of the boundary elements were investigated. The HSC wall exhibited improved strength and stiffness, and thereby, allowed reduction in the longitudinal reinforcement area and size of the boundary elements for the same strength of the conventional wall. Cold joints resulting from dissimilar concrete pours in the web and boundary elements of the HSC wall were modeled and their impact on behavior of the wall was examined.

关键词： slender walls high-strength concrete rectangular and barbell-shaped walls cold joints

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Stability of three-dimensional printable foam concrete as function of surfactant characteristics

《结构与土木工程前沿（英文）》页码 935-947 doi: 10.1007/s11709-023-0964-z

摘要： Extrudability is one of the most critical factors when designing three-dimensional printable foam concrete. The extrusion process likely affects the foam stability which necessitates the investigation into surfactant properties particularly for concrete mixes with high foam contents. Although many studies have been conducted on traditional foam concrete in this context, studies on three-dimensional printed foam concrete are scarce. To address this research gap, the effects of surfactant characteristics on the stability, extrudability, and buildability of three-dimensional printed foam concrete mixes with two design densities (1000 and 1300 kg/m³) using two different surfactants and stabilizers (synthetic-based sodium lauryl sulfate stabilized with carboxymethyl cellulose sodium salt, and natural-based hingot surfactant stabilized with xanthan gum) were investigated in this study. Fresh density tests were conducted before and after the extrusion to determine stability of the foam concrete. The results were then correlated with surfactant qualities, such as viscosity and surface tension, to understand the importance of key parameters in three-dimensional printing of foam concrete. Based on the experimental results, surfactant solu1tion with viscosity exceeding 5 mPa·s and surface tension lower than 31 mN/m was recommended to yield stable three-dimensional printable foam concrete mixes. Nevertheless, the volume of foam in the mix significantly affected the printability characteristics. Unlike traditional foam concrete, the variation in the stabilizer concentration and density of concrete were found to have insignificant effect on the fresh-state-characteristics (slump, slump flow, and static yield stress) and air void microstructure of the stable mixes.

关键词： foam concrete 3D printable concrete stability rheology air void microstructure

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厦门翔安海底隧道衬砌水压力特征研究

程正明

《中国工程科学》 2012年第14卷第11期页码 29-35

摘要：

合理确定衬砌水压力是海底隧道结构设计的关键所在。采用复变函数和地下水动力学理论，推导了圆形海底隧道衬砌外水压力解析法计算公式，经对比验证，精度高、适用性广。通过海底隧道水压力模型试验研究得到，全封堵防水方式下，衬砌背后水压不能折减；限量排放时，衬砌背后水压力随排水量的增加而减小，建立了限量排放下的水压力计算公式，得到现场实测结果验证。研究成果应用于国内第一条海底隧道──厦门翔安海底隧道，为“以堵为主、限量排放”的支护结构设计和海底风化槽地段注浆堵水方案的制订提供了关键技术参数，现场应用成效良好。相关研究成果对后续海底隧道工程具有一定借鉴意义。

关键词：海底隧道衬砌水压力模型试验限量排放折减

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Factors influencing the somatic cell nuclear transfer efficiency in pigs

Qiang XIONG, Lihua ZHAO, Xiaowei NIE, Daorong HOU, Qiang LIU, Junzheng WANG, Chenyu WANG, Xiaokang LI, Lining

《农业科学与工程前沿（英文）》 2019年第6卷第1期页码 73-80 doi: 10.15302/J-FASE-2018220

摘要：

Using a data set from our laboratory, we assessed the effects of several factors on pig cloning efficiency. The results demonstrated that cells at high confluence (>90%) used as donor cell resulted in higher pregnancy rate, delivery rate and overall cloning efficiency (number of live offspring born per reconstructed embryo transferred to recipients) compared with the cells at 60% to 79% confluence and 80% to 89% confluence. Cells with four, five and six passages compromised the pregnancy and delivery rates compared with first passage cells. The number of blastocysts transferred by somatic cell nuclear transfer (SCNT) did not significantly affect the cloning efficiency, but transfer of blastocyst derived from culture 5 d after SCNT achieved a significantly higher pregnancy rate compared with one to two cell SCNT embryos from overnight culture. The highest pregnancy rate, delivery rate and the largest litter size were obtained when Bama Miniature pig fibroblasts were used as donor cells and Landrace/Yorkshire hybrid gilts were used as recipients. Recipients treated with chemicals for estrus synchronization had higher pregnancy rates compared with untreated recipients. Our data might be helpful for improving SCNT efficiency in pigs.

关键词： blastocyst donor cell estrus synchronization pregnancy rate pig cloning somatic cell nuclear transfer