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A new method of studying collapsibility of loess

Yuanqing ZHU , Zhenghan CHEN ,

《结构与土木工程前沿（英文）》 2009年第3卷第3期页码 305-311 doi: 10.1007/s11709-009-0040-3

摘要： A new triaxial testing system that could control suction in wetting-induced collapsible tests was successfully developed to study the suction effects on wetting-induced collapsible deformation. The pedestal of the triaxial cell was made up of two parts, and the equipment not only could control suction but also could make water accessible to soil. A pressure/volume-controlled equipment was combined with the triaxial system to measure the water volume absorbed by samples accurately and to add pressure on water to filtrate into the sample. The apparatus could measure volume change precisely and keep the deviator stress unvaried, as well as measure the volume of water filtrating into the samples exactly. A triaxial collapsible testing procedure was described using the new apparatus for undisturbed collapsible loess with controlled suction. Furthermore, a series of double triaxial collapsible tests were conducted under different suctions and the same net cell pressure, and tests under different net cell pressures and the same suction were also done. It was indicated that the collapsible deformation increased with the increasing suction, and the effect of the net cell pressure on collapsible deformation was remarkable. The new triaxial apparatus was a useful facility to study the collapsible behavior of loess.

关键词： triaxial apparatus for collapsible soils controlled suction pressure/volume controlled equipment double triaxial collapsible test single triaxial collapsible test

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深海装备耐压结构用钛合金材料应用研究

蒋鹏,王启,张斌斌,王洋

《中国工程科学》 2019年第21卷第6期页码 95-101 doi: 10.15302/J-SSCAE-2019.06.018

摘要：

本文概述了国内外钛合金深海装备的发展现状，针对深海服役环境特点对耐压结构用钛合金材料的性能要求进行了分析，介绍了典型装备耐压结构钛合金材料研究应用中出现的应力腐蚀和蠕变等技术问题，提出需要针对钛合金材料长期服役时存在的组织演变和性能衰减、冲击环境下的动态响应等基础科学问题开展研究，重点梳理工程应用中的大规格材料、应用评价和高效建造等关键技术。文章建议针对深海领域钛合金装备的迫切需求，进一步加大钛合金材料基础研究和工程化应用力度，推动创新应用，践行海洋强国战略。

关键词：深海装备耐压结构钛合金关键技术

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论岩土塑性体应变与剪应变的相互作用原理

王靖涛

《中国工程科学》 2006年第8卷第9期页码 24-29

摘要：

对岩土塑性变形过程中体应变与剪应变的相互作用原理的内涵做了深入的阐述，特别对塑性体应变和剪应变之间的相互作用方式，塑性体应变对抗剪能力的直接控制作用，剪缩和剪胀发生的条件，应力路径相关性是这种相互作用的综合体现及实例验证，临界状态是塑性和弹性体应变都保持不变的纯粹剪切变形过程等方面进行了论证；根据这个相互作用原理，在理论上证明了空间临界状态线的存在性和唯一性以及它与应力是无关的。

关键词：岩土塑性体变形和剪应变的相互作用原理岩土本构关系压硬性剪胀性

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采用分布式光纤传感技术的土坝模型渗漏监测分析

杜朝伟,王梦恕,谭忠盛

《中国工程科学》 2011年第13卷第3期页码 86-91

摘要：

海底隧道应采取堵水限排的地下水处理方式，为了研究堵水限排海底隧道围岩压力、初期支护水压力和钢拱架内力在施工阶段的变化规律，结合厦门海底隧道工程，对施工现场的围岩压力、初期支护后水压力和钢拱架内力进行实时监测。研究表明，初期支护在施工阶段有较高的安全系数，止水超前注浆和初期支护背后注浆对海底隧道非常有必要。在堵水限排情况下，通过加强注浆等工程措施，初期支护水压力可降至静水压力的1/3。通过对施工现场排水量的监测与分析，提出了排水量控制标准，厦门海底隧道软弱围岩地段的排水量应按照0.25 m³/（m·d）控制。研究成果在厦门海底隧道中得到了验证和应用。

关键词：厦门海底隧道堵水限排施工监测水压力排水量

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Assessment of liver volume variation to evaluate liver function

null

《医学前沿（英文）》 2012年第6卷第4期页码 421-427 doi: 10.1007/s11684-012-0223-5

摘要：

In order to assess the value of liver volumetry in cirrhosis and acute liver failure (ALF) patients, we explored the correlation between hepatic volume and severity of the hepatic diseases. The clinical data of 48 cirrhosis patients with 60 normal controls and 39 ALF patients were collected. Computed tomography-derived liver volume (CTLV) and body surface area (BSA) of normal controls were calculated to get a regression formula for standard liver volume (SLV) and BSA. Then CTLV and SLV of all patients were calculated and grouped by Child-Turcotte-Pugh classification for cirrhosis patients and assigned according to prognosis of ALF patients for further comparison. It turned out that the mean liver volume of the control group was 1 058±337 cm³. SLV was correlated with BSA according to the regression formula. The hepatic volume of cirrhosis patients in Child A, B level was not reduced, but in Child C level it was significantly reduced with the lowest liver volume index (CTLV/SLV). Likewise, in the death group of ALF patients, the volume index was significantly lower than that of the survival group. Based on volumetric study, we proposed an ROC (receiver operating characteristic) analysis to predict the prognosis of ALF patients that CTLV/SLV<83.9% indicates a poor prognosis. In conclusion, the CTLV/SLV ratio, which reflects liver volume variations, correlates well with the liver function and progression of cirrhosis and ALF. It is also a very useful marker for predicting the prognosis of ALF.

关键词： liver volume variation cirrhosis acute liver failure (ALF)

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Synthesis and characterization of biocompatible polyurethanes for controlled release of hydrophobic and

Juichen YANG,Hong CHEN,Yuan YUAN,Debanjan SARKAR,Jie ZHENG

《化学科学与工程前沿（英文）》 2014年第8卷第4期页码 498-510 doi: 10.1007/s11705-014-1451-9

摘要： Design of biocompatible and biodegradable polymer systems for sustained and controlled release of bioactive agents is critical for numerous biomedical applications. Here, we designed, synthesized, and characterized four polyurethane carrier systems for controlled release of model drugs. These polyurethanes are biocompatible and biodegradable because they consist of biocompatible poly(ethylene glycol) or poly(caprolactone diol) as soft segment, linear aliphatic hexamethylene diisocyanate or symmetrical aliphatic cyclic dicyclohexylmethane-4,4′-diisocyanate as hard segment, and biodegradable urethane linkage. They were characterized with Fourier transform infrared spectroscopy, atomic force microscope, and differential scanning calorimetry, whereas their degradation behaviors were investigated in both phosphate buffered saline and enzymatic solutions. By tuning polyurethane segments, different release profiles of hydrophobic and hydrophilic drugs were obtained in the absence and presence of enzymes. Such difference in release profiles was attributed to a complex interplay among structure, hydrophobicity, and degradability of polyurethanes, the size and hydrophobicity of drugs, and drug-polymer interactions. Different drug-polyurethane combinations modulated the distribution and location of the drugs in polymer matrix, thus inducing different drug release mechanisms. Our results highlight an important role of segmental structure of the polyurethane as an engineering tool to control drug release.

关键词： phase structure degradation polyurethanes controlled release drug delivery

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Destructive and non-destructive evaluation of concrete for optimum sand to aggregate volume ratio

《结构与土木工程前沿（英文）》 2021年第15卷第6期页码 1400-1414 doi: 10.1007/s11709-021-0779-8

摘要： Aggregates are the biggest contributor to concrete volume and are a crucial parameter in dictating its mechanical properties. As such, a detailed experimental investigation was carried out to evaluate the effect of sand-to-aggregate volume ratio (s/a) on the mechanical properties of concrete utilizing both destructive and non-destructive testing (employing UPV (ultrasonic pulse velocity) measurements). For investigation, standard cylindrical concrete samples were made with different s/a (0.36, 0.40, 0.44, 0.48, 0.52, and 0.56), cement content (340 and 450 kg/m³), water-to-cement ratio (0.45 and 0.50), and maximum aggregate size (12 and 19 mm). The effect of these design parameters on the 7, 14, and 28 d compressive strength, tensile strength, elastic modulus, and UPV of concrete were assessed. The careful analysis demonstrates that aggregate proportions and size need to be optimized for formulating mix designs; optimum ratios of s/a were found to be 0.40 and 0.44 for the maximum aggregate size of 12 and 19 mm, respectively, irrespective of the W/C (water-to-cement) and cement content.

关键词： aggregates non-destructive testing sand-to-aggregate volume ratio (s/a) maximum aggregate size (MAS)

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岩溶隧道衬砌水压力分布规律研究

谭忠盛,李健,薛斌,王秀英

《中国工程科学》 2009年第11卷第12期页码 87-92

摘要：

长期以来隧道衬砌水压力问题，一直是人们争论的焦点。依托宜万铁路岩溶隧道工程，对不同防排水方式（即全封堵、堵排结合及排放方式）的隧道衬砌水压力分布规律进行研究，研究方法主要采用模型试验及现场测试方法，模型试验的比例尺为1∶16，试验台架可同时施加土压和水压。通过模型试验得出水压力分布规律：全封堵条件下衬砌背后水压力不能折减，注浆圈也不能有效减小水压力；隧道内排水后衬砌背后水压力明显减小，并随着排水量的增加，水压力基本成直线下降；相同排水量时，注浆效果越好，衬砌背后水压力减小越明显；隧道采用全排导方式时，衬砌仍承受一定的水压。由模型试验得出的水压分布规律的部分结论，在现场水压力测试中得到了验证。

关键词：岩溶隧道全封堵限量排放水压力模型试验

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Integration of molecular dynamic simulation and free volume theory for modeling membrane VOC/gas separation

Bo Chen, Yan Dai, Xuehua Ruan, Yuan Xi, Gaohong He

《化学科学与工程前沿（英文）》 2018年第12卷第2期页码 296-305 doi: 10.1007/s11705-018-1701-3

摘要： Gas membrane separation process is highly unpredictable due to interacting non-ideal factors, such as composition/pressure-dependent permeabilities and real gas behavior. Although molecular dynamic (MD) simulation can mimic those complex effects, it cannot precisely predict bulk properties due to scale limitations of calculation algorithm. This work proposes a method for modeling a membrane separation process for volatile organic compounds by combining the MD simulation with the free volume theory. This method can avoid the scale-up problems of the MD method and accurately simulate the performance of membranes. Small scale MD simulation and pure gas permeation data are employed to correlate pressure-irrelevant parameters for the free volume theory; by this approach, the microscopic effects can be directly linked to bulk properties (non-ideal permeability), instead of being fitted by a statistical approach. A lab-scale hollow fiber membrane module was prepared for the model validation and evaluation. The comparison of model predictions with experimental results shows that the deviations of product purity are reduced from 10% to less than 1%, and the deviations of the permeate and residue flow rates are significantly reduced from 40% to 4%, indicating the reliability of the model. The proposed method provides an efficient tool for process engineering to simulate the membrane recovery process.

关键词： membrane vapor separation membrane process modeling process engineering free volume theory volatile organic compound

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Size-controlled green synthesis of silver nanoparticles assisted by L-cysteine

Wenchao Zhang,Lin Zhang,Yan Sun

《化学科学与工程前沿（英文）》 2015年第9卷第4期页码 494-500 doi: 10.1007/s11705-015-1527-1

摘要： A green and size-controlled synthesis of silver nanoparticles (Ag NPs) in aqueous solution with the assistance of L-cysteine is presented. The size of Ag NPs decreases with the increase of L-cysteine concentration, and thus can be controlled by adjusting L-cysteine concentration. TEM analysis shows that Ag NPs with an average size of 3 nm can be produced in the presence of 1.0 mmol/L L-cysteine, about one sixth of the size of Ag NPs obtained in the absence of L-cysteine (17 nm). The as-synthesized silver colloidal solution is stable and can be stored at room temperature for at least two months without any precipitation. This L-cysteine assisted method is simple, feasible and efficient, and would facilitate the production and application of Ag NPs.

关键词： nanoparticles silver L-cysteine size distribution synthesis

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Analysis and stabilization control of a voltage source controlled wind farm under weak grid conditions

《能源前沿（英文）》 2022年第16卷第6期页码 943-955 doi: 10.1007/s11708-021-0793-5

摘要： This paper investigates and discusses the interaction stability issues of a wind farm with weak grid connections, where the wind turbines (WTs) are controlled by a new type of converter control strategy referred to as the voltage source (VS) control. The primary intention of the VS control method is to achieve the high-quality inertial response capability of a single WT. However, when it is applied to multiple WTs within a wind farm, its weak-grid performance regarding the stability remains concealed and needs to be clarified. To this end, a frequency domain model of the wind farm under the VS control is first developed. Based on this model and the application of a stability margin quantification index, not only the interactions between the wind farm and the weak grid but also those among WTs will be systematically assessed in this paper. A crucial finding is that the inertial response of VS control has negative impacts on the stability margin of the system, and the dominant instability mode is more related to the interactions among the WTs rather than the typical grid-wind farm interaction. Based on this knowledge, a stabilization control strategy is then proposed, aiming for stability improvements of VS control while fulfilling the demand of inertial responses. Finally, all the results are verified by time-domain simulations in power systems computer aided design/electromagnetic transients including DC(PSCAD/EMTDC).

关键词： weak grids voltage source (VS) control wind turbine (WT) stabilization control wind farm inertial response

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Chinese medicine patterns on patients with pneumoconiosis: a pilot double-blind, randomized, and placebo-controlled

《医学前沿（英文）》 2022年第16卷第5期页码 736-744 doi: 10.1007/s11684-021-0870-5

摘要： Effective therapy options for pneumoconiosis are lacking. Traditional Chinese medicine (TCM) presents a favorable prospect in the treatment of pneumoconiosis. A pilot study on TCM syndrome differentiation can evaluate the clinical efficacy and safety of TCM and lay a foundation for further clinical research. A double-blind, randomized, and placebo-controlled trial was conducted for 24 weeks, in which 96 patients with pneumoconiosis were randomly divided into the control and treatment groups. Symptomatic treatment was conducted for the two groups. The treatment group was treated with TCM syndrome differentiation, and the control group was treated with placebo. The primary outcomes were the six-minute walking distance (6MWD) and the St. George Respiratory Questionnaire (SGRQ) score. The secondary outcomes were the modified British Medical Research Council Dyspnea Scale (mMRC), Chronic Obstructive Pulmonary Disease Assessment Test (CAT), Hospital Anxiety and Depression Scale (HADS), and pulmonary function. Only 83 patients from the 96 patients with pneumoconiosis finished the study. For the primary outcome, compared with the control groups, the treatment group showed a significantly increased 6MWD (407.90 m vs. 499.51 m; 95% confidence interval (CI) 47.25 to 135.97; P <0.001) and improved SGRQ total score (44.48 vs. 25.67; 95% CI −27.87 to −9.74; P <0.001). The treatment group also significantly improved compared with the control group on mMRC score (1.4 vs. 0.74; 95% CI −1.08 to −0.23; P =0.003), CAT score (18.40 vs. 14.65; 95% CI −7.07 to −0.43; P =0.027), and the total symptom score (7.90 vs. 5.14; 95% CI −4.40 to −1.12; P <0.001). No serious adverse events occurred. This study showed that TCM syndrome differentiation and treatment had a favorable impact on the exercise endurance and quality of life of patients with pneumoconiosis.

关键词： pneumoconiosis randomized controlled trials traditional Chinese medicine

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Applications of thermostatically controlled loads for demand response with the proliferation of variable

Meng SONG, Wei SUN

《能源前沿（英文）》 2022年第16卷第1期页码 64-73 doi: 10.1007/s11708-021-0732-5

摘要： More flexibility is desirable with the proliferation of variable renewable resources for balancing supply and demand in power systems. Thermostatically controlled loads (TCLs) attract tremendous attentions because of their specific thermal inertia capability in demand response (DR) programs. To effectively manage numerous and distributed TCLs, intermediate coordinators, e.g., aggregators, as a bridge between end users and dispatch operators are required to model and control TCLs for serving the grid. Specifically, intermediate coordinators get the access to fundamental models and response modes of TCLs, make control strategies, and distribute control signals to TCLs according the requirements of dispatch operators. On the other hand, intermediate coordinators also provide dispatch models that characterize the external characteristics of TCLs to dispatch operators for scheduling different resources. In this paper, the bottom-up key technologies of TCLs in DR programs based on the current research have been reviewed and compared, including fundamental models, response modes, control strategies, dispatch models and dispatch strategies of TCLs, as well as challenges and opportunities in future work.

关键词： thermostatically controlled load demand response renewable energy power system operation

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All-in-one functional supramolecular nanoparticles based on pillar[5]arene for controlled generation,

《化学科学与工程前沿（英文）》 2023年第17卷第3期页码 307-313 doi: 10.1007/s11705-022-2216-5

摘要： The storage and controlled release of singlet oxygen (¹O₂) have attracted increasing attention due to the wide application and microsecond lifetime of ¹O₂ in water. Herein we provide an integrated nanoplatform consisting of a diphenylanthracene derivative, a water-soluble pillar[5]arene and a photosensitizer tetrakis(4-hydroxyphenyl)porphyrin (TPP), that may provide the controlled generation, storage and release of singlet oxygen. We design a new diphenylanthracene derivative with two trimethylammonium bromide groups on both ends that can be well recognized by the pillar[5]arene. The formed nanocarriers can be used to load TPP through their supramolecular self-assembly. The resulting nanoparticles show good water-solubility and uniform spherical morphology. After laser irradiation (660 nm), the nanoparticles exhibit excellent ability for the generation and storage of ¹O₂. When the irradiated nanoparticles are heated above 80 °C, ¹O₂ can be released from the system. Therefore, in this paper we pioneer the use of noncovalent interaction to integrate the diphenylanthracene derivatives and photosensitizers into one functional system, which provides a new strategy for the controlled generation, storage and release of singlet oxygen. We believe this groundbreaking strategy will have a great potential in providing necessary amounts of ¹O₂ for the photodynamic therapy of tumors in dark.

关键词： storage and controlled release of singlet oxygen supramolecular nanoparticles noncovalent interactions pillararenes diphenylanthracene photosensitizers