资源类型

期刊论文 775

会议视频 11

年份

2023 69

2022 61

2021 67

2020 47

2019 36

2018 34

2017 50

2016 25

2015 22

2014 31

2013 39

2012 22

2011 35

2010 36

2009 29

2008 47

2007 58

2006 25

2005 11

2004 5

展开 ︾

关键词

膜分离 5

仿真 4

绿色化工 4

能源 4

CAN总线 2

二氧化碳 2

低温SOFC 2

大气温度 2

实时控制 2

实时服务 2

时间序列 2

温度 2

温度分布 2

温度控制 2

聚偏氟乙烯 2

高温气冷堆 2

(美国) 核管理委员会 1

10kV高压电力电缆 1

2 Mb/s高速信令 1

展开 ︾

检索范围：

排序： 展示方式：

Phase separation time/temperature dependence of thermoplastics-modified thermosetting systems

ZHANG Xiujuan, XU Yuanze, YI Xiaosu

《化学科学与工程前沿（英文）》 2008年 第2卷 第3期   页码 276-285 doi: 10.1007/s11705-008-0057-5

摘要： The cure-induced phase separation processes of various thermoplastics(TP)-modified thermosetting systems which show upper critical solution temperature (UCST) or lower critical solution temperature (LCST) were studied with emphasis on the temperature dependency of the phase separation time and its potential application in the cure time-temperature processing window. We found that the phase separation time/temperature relationship follows the simple Arrhenius equation. The cure-induced phase separation activation energy (ps) generated from the linear fitting of the Arrhenius equation is irrelevant to the detection means of phase separation time. We also found that (ps) is insensitive to TP content, TP molecular weight and curing rate, but it changes with the cure reaction kinetics and the chemical environment of the systems. With the established phase separation time-temperature dependence relation, we can easily establish the whole cure time-temperature transformation (TTT) diagram with morphology information which is a useful map for the TP/TS composites processing industry.

关键词： separation time-temperature     temperature dependency     cure-induced     separation activation     temperature    

HTML PDF 收藏

Development of realistic design fire time-temperature curves for the testing of cold-formed steel wall

Anthony Deloge ARIYANAYAGAM,Mahen MAHENDRAN

《结构与土木工程前沿（英文）》 2014年 第8卷 第4期   页码 427-447 doi: 10.1007/s11709-014-0279-1

摘要： Fire resistance rating of light gauge steel frame (LSF) wall systems is obtained from fire tests based on the standard fire time-temperature curve. However, fire severity has increased in modern buildings due to higher fuel loads as a result of modern furniture and light weight constructions that make use of thermoplastics materials, synthetic foams and fabrics. Some of these materials are high in calorific values and increase both the spread of fire growth and heat release rate, thus increasing the fire severity beyond that of the standard fire curve. Further, the standard fire curve does not include a decay phase that is present in natural fires. Despite the increasing usage of LSF walls, their behavior in real building fires is not fully understood. This paper presents the details of a research study aimed at developing realistic design fire curves for use in the fire tests of LSF walls. It includes a review of the characteristics of building fires, previously developed fire time-temperature curves, computer models and available parametric equations. The paper highlights that real building fire time-temperature curves depend on the fuel load representing the combustible building contents, ventilation openings and thermal properties of wall lining materials, and provides suitable values of many required parameters including fuel loads in residential buildings. Finally, realistic design fire time-temperature curves simulating the fire conditions in modern residential buildings are proposed for the testing of LSF walls.

关键词： fire safety     standard fire curve     realistic design fire time-temperature curves     light gauge steel frame (LSF) walls     fire resistance rating     fuel load    

HTML PDF 收藏

国产环氧沥青混合料固化强度增长规律研究

钱振东,王亚奇,沈家林

《中国工程科学》 2012年 第14卷 第5期   页码 90-95

摘要：

研究了环氧沥青混合料的强度形成机理，在此基础上对影响环氧沥青混合料强度的两个重要因素即混合料的容留时间、养生温度进行了研究，确定了不同温度下环氧沥青混合料的容留时间范围及强度增长规律；采用差示扫描量热法（DSC）测得环氧沥青结合料在不同升温速率下的动态DSC曲线，通过非线性回归求得固化动力学关键参数，建立环氧沥青结合料的固化反应模型。研究结果可以指导环氧沥青混合料的生产与施工，同时对铺装层开放交通时间的确定有参考意义。

关键词： 环氧沥青     强度增长     时温条件     固化反应模型    

HTML PDF 收藏

Effects of pressure and temperature on fixed-site carrier membrane for CO 2 separation from natural gas

Meng WANG, Dongxiao YANG, Zhi WANG, Jixiao WANG, Shichang WANG,

《化学科学与工程前沿（英文）》 2010年 第4卷 第2期   页码 127-132 doi: 10.1007/s11705-009-0231-4

摘要： In this paper, the effect of testing temperature on the performance of fixed carrier membrane for CO separation were studied. The blend composite membranes were developed respectively with a blend of PEI-PVA (polyetheleneimine-polyvinyl alcohol) as separation layer and PS (polysulfone) ultrafiltration membranes as the substrates. The permselectivity of the membranes was measured with CO/CH mixed gas. The effect of testing temperature on membrane separation performance was investigated. The results showed that both the permeances of CO and CH decreased with the increase of temperature, and the permeances decreased more quickly under low pressure than those under high pressure. At the feed pressure of 0.11MPa, the CO/ CH selectivity of PEI-PVA/PS blend composite membrane reduced along with temperature increment. Under the feed pressure of 0.21MPa, as well as 1.11MPa, the selectivity decreased with the increase of temperature.

关键词： temperature increment     high pressure     permselectivity     separation performance     temperature    

HTML PDF 收藏

新型碳酚醛材料动静态力学性能和本构关系研究

张泰,王肖钧,王志海,郭扬,王元博

《中国工程科学》 2006年 第8卷 第5期   页码 63-68

摘要：

研究了碳纤维增强酚醛复合材料在不同温度下的动静态压缩力学性能，碳酚醛材料不但是应变率敏感材料，也是温度相关材料；提出了一个非线性粘弹性本构方程，通过对实验应力-应变曲线的拟合给出了本构方程的材料参数，讨论了温度对本构方程参数的影响；分析了材料力学行为的时温等效性，给出了不同加载条件下的时温等效曲线。

关键词： 碳酚醛     力学性能     粘弹性     本构模型     时温等效    

HTML PDF 收藏

Applicability of the Arrhenius model for Ammonia Oxidizing Bacteria subjected to temperature time gradients

Alberto MANNUCCI,Giulio MUNZ,Gualtiero MORI,Claudio LUBELLO,Jan A. OLESZKIEWICZ

《环境科学与工程前沿（英文）》 2015年 第9卷 第6期   页码 988-994 doi: 10.1007/s11783-014-0751-0

摘要： The aim of this work is to identify the range of applicability of Arrhenius type temperature dependence for Ammonia Oxidizing Bacteria (AOB) subjected to temperature time gradients through continuous titrimetric tests. An innovative online differential titrimetric technique was used to continuously monitor the maximum biologic ammonia oxidation rate of the biomass selected in a pilot scale membrane bioreactor, as a function of temperature time gradients. The monitoring technique is based on the measurement of alkalinity and hydrogen peroxide consumption rates in two parallel reactors operated in non-limiting substrate conditions for AOB; both reactors were continuously fed with mixed liquor and in one of them AOB were inhibited with allylthiourea. The effects of temperature decrease rates in the range 1 to 4°C·h were evaluated by controlling the titrimetric reactor in the temperature range 10°C–20°C. The dependence of growth kinetics on temperature time gradients and the range of applicability of Arrhenius model for temperature dependency of AOB growth kinetics were assessed. The Arrhenius model was found to be accurate only with temperature gradients lower than 2°C·h . The estimated Arrhenius coefficients ( ) were shown to increase from 1.07 to 1.6 when the temperature decrease rate reached 4°C·h .

关键词： nitrification rate     temperature effect     continuous titrimetric tests     time-gradient temperature variations     Ammonia Oxidizing Bacteria (AOB)    

HTML PDF 收藏

Real-time tool condition monitoring method based on temperature measurement and artificial neural network

《机械工程前沿（英文）》 doi: 10.1007/s11465-021-0661-3

摘要： Tool failures in machining processes often cause severe damages of workpieces and lead to large quantities of loss, making tool condition monitoring an important, urgent issue. However, problems such as practicability still remain in actual machining. Here, a real-time tool condition monitoring method integrated in an in situ fiber optic temperature measuring apparatus is proposed. A thermal simulation is conducted to investigate how the fluctuating cutting heats affect the measuring temperatures, and an intermittent cutting experiment is carried out, verifying that the apparatus can capture the rapid but slight temperature undulations. Fourier transform is carried out. The spectrum features are then selected and input into the artificial neural network for classification, and a caution is given if the tool is worn. A learning rate adaption algorithm is introduced, greatly reducing the dependence on initial parameters, making training convenient and flexible. The accuracy stays 90% and higher in variable argument processes. Furthermore, an application program with a graphical user interface is constructed to present real-time results, confirming the practicality.

关键词： tool condition monitoring     cutting temperature     neural network     learning rate adaption    

HTML PDF 收藏

Computational fluid dynamics applied to high temperature hydrogen separation membranes

Guozhao JI, Guoxiong WANG, Kamel HOOMAN, Suresh BHATIA, Jo?o C. DINIZ da COSTA

《化学科学与工程前沿（英文）》 2012年 第6卷 第1期   页码 3-12 doi: 10.1007/s11705-011-1161-5

摘要： This work reviews the development of computational fluid dynamics (CFD) modeling for hydrogen separation, with a focus on high temperature membranes to address industrial requirements in terms of membrane systems as contactors, or in membrane reactor arrangements. CFD modeling of membranes attracts interesting challenges as the membrane provides a discontinuity of flow, and therefore cannot be solved by the Navier-Stokes equations. To address this problem, the concept of source has been introduced to understand gas flows on both sides or domains (feed and permeate) of the membrane. This is an important solution, as the gas flow and concentrations in the permeate domain are intrinsically affected by the gas flow and concentrations in the feed domain and vice-versa. In turn, the source term will depend on the membrane used, as different membrane materials comply with different transport mechanisms, in addition to varying gas selectivity and fluxes. This work also addresses concentration polarization, a common effect in membrane systems, though its significance is dependent upon the performance of the membrane coupled with the operating conditions. Finally, CFD modeling is shifting from simplified single gas simulation to industrial gas mixtures, when the mathematical treatment becomes more complex.

关键词： membrane     gas separation     computational fluid dynamics     concentration polarization     hydrogen    

HTML PDF 收藏

Room temperature preparation of hydrazine-linked covalent organic frameworks coated capillaries forseparation and determination of polycyclic aromatic hydrocarbons

《化学科学与工程前沿（英文）》 2023年 第17卷 第5期   页码 548-556 doi: 10.1007/s11705-022-2252-1

摘要： Covalent organic frameworks (COFs) have been increasingly used in capillary electrochromatography due to their excellent characteristics. In this work, hydrazine-linked TFPB-DHzDS (TFPB: 1,3,5-tris(4-formylphenyl)benzene; DHzDS: 2,5-bis(3-(ethylthio)propoxy)terephthalohydrazide) was first synthesized by a simpler and easier method at room temperature and introduced into capillary electrochromatography as coating material. The TFPB-DHzDS coated capillaries were prepared by an in-situ growth process at room temperature. After optimizing the coating concentration and experimental conditions of capillary electrochromatography, baseline separation of two groups of polycyclic aromatic hydrocarbons was achieved based on the TFPB-DHzDS coated capillary. And the established method was used successfully to determine PAHs in natural water and soil samples. The spiked recoveries of polycyclic aromatic hydrocarbons in these samples ranged from 90.01% to 111.0%, indicating that the method is reliable and could detect polycyclic aromatic hydrocarbons in natural samples. Finally, molecular simulation was applied to study and visualize the interaction between the analytes and coating COF materials to investigate the molecular level separation mechanism further.

关键词： hydrazine-linked TFPB-DHzDS     in-situ growth method     open-tubular capillary electrochromatography     molecular simulations    

HTML PDF 收藏

Evaluating the short-term effect of ambient temperature on non-fatal outdoor falls and road traffic injuriesamong children and adolescents in China: a time-stratified case-crossover study

《环境科学与工程前沿（英文）》 2023年 第17卷 第9期 doi: 10.1007/s11783-023-1705-1

摘要：

● A study assessing the temperature-injury relationship was conducted among students.

关键词： Ambient temperature     Fall     Road traffic injury     Student     China    

HTML PDF 收藏

Achieving High Strength and Tensile Ductility in Pure Nickel by Cryorolling with Subsequent Low-TemperatureShort-Time Annealing

Zhide Li,Hao Gu,Kaiguang Luo,Charlie Kong,Hailiang Yu,

《工程（英文）》 doi: 10.1016/j.eng.2023.01.019

摘要： ty. In this study, cryorolling under different strains followed by low-temperature short-time annealing was used to fabricate pure nickel sheets combining high strength with good ductility. The results show that, for different cryorolling strains, the uniform elongation was greatly increased without sacrificing the strength after annealing. A yield strength of 607 MPa and a uniform elongation of 11.7% were obtained after annealing at a small cryorolling strain (ε = 0.22), while annealing at a large cryorolling strain (ε = 1.6) resulted in a yield strength of 990 MPa and a uniform elongation of 6.4%. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and electron backscattered diffraction (EBSD) were used to characterize the microstructure of the specimens and showed that the high strength could be attributed to strain hardening during cryorolling, with an additional contribution from grain refinement and the formation of dislocation walls. The high ductility could be attributed to annealing twins and micro-shear bands during stretching, which improved the strain hardening capacity. The results show that the synergistic effect of strength and ductility can be regulated through low-temperature short-time annealing with different cryorolling strains, which provides a new reference for the design of future thermo-mechanical processes.

关键词： Cryorolling     Annealing     Nickel     Strain hardening     Ductility    

HTML PDF 收藏

Time- and temperature-dependence of compressive and tensile behaviors of polypropylene fiber-reinforced

《结构与土木工程前沿（英文）》 2021年 第15卷 第4期   页码 1025-1037 doi: 10.1007/s11709-021-0741-9

摘要： The understanding of compressive and tensile behaviors of polypropylene fiber-reinforced cemented paste backfill (FR-CPB) play crucial roles in the successful implementation of reinforcement technique in underground mine backfilling operations. However, very limited studies have been performed to gain insight into the evolution of compressive and tensile behaviors and associated mechanical properties of FR-CPB under various curing temperatures from early to advanced ages. Thus, this study aims to investigate the time (7, 28, and 90 d)- and temperature (20°C, 35°C, and 45°C)-dependence of constitutive behavior and mechanical properties of FR-CPB. The obtained results show that pre- and post-failure behaviors of FR-CPB demonstrate strongly curing temperature-dependence from early to advanced ages. Moreover, the pseudo-hardening behavior is sensitive to curing temperature, especially at early ages. Furthermore, the mechanical properties including elastic modulus, material stiffness, strengths, brittleness, cohesion, and internal friction angle of FR-CPB show increasing trends with curing temperature as curing time elapses. Additionally, a predictive model is developed to capture the strong correlation between compressive and tensile strength of FR-CPB. The findings of this study will contribute to the successful implementation of FR-CPB technology.

关键词： cemented paste backfill     fiber reinforcement     constitutive behavior     temperature     tailings    

HTML PDF 收藏

Operating characteristic analysis on the ultra-thin low temperature floor-heating system

Hualing ZHANG, Xiaopeng SONG

《结构与土木工程前沿（英文）》 2013年 第7卷 第2期   页码 127-132 doi: 10.1007/s11709-013-0200-3

摘要： Prefabricated ultra-thin radiant heating panel, as a new heating terminal type, is becoming a highlight in Yangtze River Valley area, China recently. However, there is a lack of operating characteristic research in this region, especially the energy consumption and operating mode are even less. To obtain these data, a heating system was set up in a duplex house in Chongqing. The test results show that the floor heating system could almost satisfy thermal comfort requirement at supply water temperature 45°C. But the preheating time was up to 4.5 h which was 1 h longer than that at supply water temperature 50°C. Meanwhile, the energy consumption at supply water temperature 50°C increased 0.10 Nm /h, and the operating efficiency decrease about 2.6% compared to those at water temperature 45°C. Considering both the thermal lag and operating efficiency, a reasonable suggestion was proposed in this paper. That was, the standard families which just stay home at night should adopt the interim mode of partial room with part time. And the supply water temperature should be properly raised during the preheating period and lowered down in the steady heating stage.

关键词： ultra-thin floor heating panel     the preheating time     thermal comfort     energy saving    

HTML PDF 收藏

Unknown fault detection for EGT multi-temperature signals based on self-supervised feature learning and

《能源前沿（英文）》 2023年 第17卷 第4期   页码 527-544 doi: 10.1007/s11708-023-0880-x

摘要： Intelligent power systems can improve operational efficiency by installing a large number of sensors. Data-based methods of supervised learning have gained popularity because of available Big Data and computing resources. However, the common paradigm of the loss function in supervised learning requires large amounts of labeled data and cannot process unlabeled data. The scarcity of fault data and a large amount of normal data in practical use pose great challenges to fault detection algorithms. Moreover, sensor data faults in power systems are dynamically changing and pose another challenge. Therefore, a fault detection method based on self-supervised feature learning was proposed to address the above two challenges. First, self-supervised learning was employed to extract features under various working conditions only using large amounts of normal data. The self-supervised representation learning uses a sequence-based Triplet Loss. The extracted features of large amounts of normal data are then fed into a unary classifier. The proposed method is validated on exhaust gas temperatures (EGTs) of a real-world 9F gas turbine with sudden, progressive, and hybrid faults. A comprehensive comparison study was also conducted with various feature extractors and unary classifiers. The results show that the proposed method can achieve a relatively high recall for all kinds of typical faults. The model can detect progressive faults very quickly and achieve improved results for comparison without feature extractors in terms of F1 score.

关键词： fault detection     unary classification     self-supervised representation learning     multivariate nonlinear time series    

HTML PDF 收藏

mode-I and mode-II fracture behavior of fiber-reinforced cemented paste backfill: Effect of curing temperatureand curing time

《结构与土木工程前沿（英文）》 2023年 第17卷 第2期   页码 256-270 doi: 10.1007/s11709-022-0924-z

摘要： The curing temperature-dependent cement hydration causes the nonlinear evolution of fracture behavior and properties of fiber-reinforced cemented paste backfill (CPB) and thus influences the stability of mine backfill materials in deep mines. Therefore, the coupled effect of curing temperature (20, 35, and 45 °C) and cement hydration at different curing times (3, 7, and 28 d) on the mode-I and mode-II fracture behavior and properties of fiber-reinforced CPB is investigated. A comprehensive experimental testing program consisting of semicircular bend tests, direct shear tests, measurement of volumetric water content and matric suction, TG/DTG tests, and SEM observation is carried out. The results show that the coupled thermochemical effect results in strongly nonlinear development of pre- and post-peak behavior of fiber-reinforced CPB. Moreover, the results discover a positive linear correlation between fracture toughness and shear strength parameters and also reveal the vital role played by matric suction in the formation of fracture toughness. Furthermore, predictive functions are developed to estimate the coupled thermochemical effect on the development of KIc and KIIc. Therefore, the findings and the developed mathematical tools have the potential to promote the successful application of fiber-reinforced CPB technology in deep underground mines.

关键词： fiber reinforcement     cemented paste backfill     fracture behavior     underground mine     cement hydration    

HTML PDF 收藏

标题 作者 时间 类型 操作

Phase separation time/temperature dependence of thermoplastics-modified thermosetting systems

ZHANG Xiujuan, XU Yuanze, YI Xiaosu

期刊论文

Development of realistic design fire time-temperature curves for the testing of cold-formed steel wall

Anthony Deloge ARIYANAYAGAM,Mahen MAHENDRAN

期刊论文

国产环氧沥青混合料固化强度增长规律研究

钱振东,王亚奇,沈家林

期刊论文

Effects of pressure and temperature on fixed-site carrier membrane for CO 2 separation from natural gas

Meng WANG, Dongxiao YANG, Zhi WANG, Jixiao WANG, Shichang WANG,

期刊论文

新型碳酚醛材料动静态力学性能和本构关系研究

张泰,王肖钧,王志海,郭扬,王元博

期刊论文

Applicability of the Arrhenius model for Ammonia Oxidizing Bacteria subjected to temperature time gradients

Alberto MANNUCCI,Giulio MUNZ,Gualtiero MORI,Claudio LUBELLO,Jan A. OLESZKIEWICZ

期刊论文

Real-time tool condition monitoring method based on temperature measurement and artificial neural network

期刊论文

Computational fluid dynamics applied to high temperature hydrogen separation membranes

Guozhao JI, Guoxiong WANG, Kamel HOOMAN, Suresh BHATIA, Jo?o C. DINIZ da COSTA

期刊论文

Room temperature preparation of hydrazine-linked covalent organic frameworks coated capillaries forseparation and determination of polycyclic aromatic hydrocarbons

期刊论文

Evaluating the short-term effect of ambient temperature on non-fatal outdoor falls and road traffic injuriesamong children and adolescents in China: a time-stratified case-crossover study

期刊论文

Achieving High Strength and Tensile Ductility in Pure Nickel by Cryorolling with Subsequent Low-TemperatureShort-Time Annealing

Zhide Li,Hao Gu,Kaiguang Luo,Charlie Kong,Hailiang Yu,

期刊论文

Time- and temperature-dependence of compressive and tensile behaviors of polypropylene fiber-reinforced

期刊论文

Operating characteristic analysis on the ultra-thin low temperature floor-heating system

Hualing ZHANG, Xiaopeng SONG

期刊论文

Unknown fault detection for EGT multi-temperature signals based on self-supervised feature learning and

期刊论文

mode-I and mode-II fracture behavior of fiber-reinforced cemented paste backfill: Effect of curing temperatureand curing time

期刊论文