资源类型

期刊论文 232

会议视频 3

年份

2023 2

2022 10

2021 11

2020 7

2019 15

2018 10

2017 8

2016 7

2015 16

2014 7

2013 10

2012 10

2011 12

2010 21

2009 23

2008 20

2007 16

2006 5

2005 3

2004 1

展开 ︾

关键词

高压 3

加压浸出 2

压力容器技术 2

因果关系图 2

工程水压爆破 2

泥水盾构 2

-10#柴油微乳剂 1

4-adj模型 1

COVID-19 1

DX桩 1

Howard正则型 1

Mittag-Leffler稳定性；分数阶；四元数神经网络；脉冲 1

S 特性 1

S型钢丝研制 1

Voronoi图 1

X射线成像 1

三向受力状态 1

下地幔 1

下沉 1

展开 ︾

检索范围：

排序： 展示方式：

Development of dimensionless P-I diagram for curved SCS sandwich shell subjected to uniformly distributedblast pressure

Yonghui WANG, Ximei ZHAI

《结构与土木工程前沿（英文）》 2019年 第13卷 第6期   页码 1432-1445 doi: 10.1007/s11709-019-0566-y

摘要： The curved steel-concrete-steel (SCS) sandwich shell was recently proposed to resist blast loading and it showed better blast resistant performance as compared to flat SCS sandwich shell via developing compressive force along the shell. In this paper, a dimensionless Pressure-Impulse (P-I) diagram was constructed as a convenient tool to predict the damage level of curved SCS sandwich shell subjected to uniformly distributed blast loading. The curved SCS sandwich shell was equivalent to a single-degree-of-freedom (SDOF) system and the equation of motion was established by employing the Lagrange’s equation. To construct the dimensionless P-I diagram, the energy balance method was utilized to yield the pressure and impulse asymptotes and the responses in the dynamic response regime were obtained via employing the SDOF method. Then, the finite element method was employed to validate the developed dimensionless P-I diagram. Finally, the procedures of using the constructed dimensionless P-I diagram to quickly conduct the blast resistant design of curved SCS sandwich shell were presented.

关键词： blast loading     curved steel-concrete-steel sandwich shell     Pressure-Impulse diagram     single-degree-of-freedom method     finite element analysis    

HTML PDF 收藏

完全信息价值的影响图求解法及其应用

刘艳琼,陈英武

《中国工程科学》 2006年 第8卷 第8期   页码 45-49

摘要：

指出了翻转决策树法求解完全信息价值时可能存在问题的根本原因，提出完全信息价值在影响图中的本质表现为信息弧，并对Howard正则型影响图定义进行修正，进而系统分析了两种不同情形下基于影响图求解完全信息价值的思路。最后举例说明。

关键词： 完全信息价值     影响图     Howard正则型    

HTML PDF 收藏

Design and optimization of reactive distillation: a review

《化学科学与工程前沿（英文）》 2022年 第16卷 第6期   页码 799-818 doi: 10.1007/s11705-021-2128-9

摘要： Reactive distillation process, a representative process intensification technology, has been widely applied in the chemical industry. However, due to the strong interaction between reaction and separation, the extension of reactive distillation technology is restricted by the difficulties in process analysis and design. To overcome this problem, the design and optimization of reactive distillation have been widely studied and illustrated for plenty of reactive mixtures over the past three decades. These design and optimization methods of the reactive distillation process are classified into three categories: graphical, optimization-based, and evolutionary/heuristic methods. The primary objective of this article is to provide an up-to-date review of the existing design and optimization methods. Desired and output information, advantages and limitations of each method are stated, the modification and development for original methodologies are also reviewed. Perspectives on future research on the design and optimization of reactive distillation method are proposed for further research.

关键词： reactive distillation     process intensification     design method     reactive phase diagram     optimization algorithm    

HTML PDF 收藏

认知无线电网络中利用信道冲击响应的主用户仿真攻击检测技术 Article

Qiao-mu JIANG, Hui-fang CHEN, Lei XIE, Kuang WANG

《信息与电子工程前沿（英文）》 2017年 第18卷 第10期   页码 1665-1676 doi: 10.1631/FITEE.1700203

摘要： 认知无线电通过将空闲频谱动态地分配给未授权用户,可以有效地解决频谱资源稀缺的问题。然而，在认知无线电网络中，存在着一种严重的拒绝服务攻击，称为“主用户仿真攻击”，该攻击会导致认知无线电网络系统性能的下降。在本文中，我们提出了一种在认知无线电网络中利用无线信道信息进行主用户仿真攻击检测的方法。在该方法中，我们利用信号源与从用户之间信道冲激响应的独特性，判断从用户接收到的信号来源是主用户还是仿真主用户。我们进一步推导了所提出检测方法的虚警概率和检测概率的闭合表达式。另外，为使所提出的检测方法在从用户没有主用户信号结构和内容先验信息的场景下也能顺利工作，我们提出了一种改进的基于子空间的盲信道估计方法。仿真结果表明，即使主用户与仿真主用户到从用户之间信道冲激响应的差别较小，所提出的主用户仿真攻击检测方法也能取得较好的检测性能。

关键词： 认知无线电网络；主用户仿真攻击；基于子空间的盲信道估计；信道冲击响应    

HTML PDF 收藏

Anefficient quadrature demodulator for medical ultrasound imaging

Hao ZHOU,Yin-fei ZHENG

《信息与电子工程前沿（英文）》 2015年 第16卷 第4期   页码 301-310 doi: 10.1631/FITEE.1400205

摘要： Quadrature demodulation is used in medical ultrasound imaging to derive the envelope and instantaneous phase of the received radio-frequency (RF) signal. In quadrature demodulation, RF signal is multiplied with the sine and cosine wave reference signal and then low-pass filtered to produce the base-band complex signal, which has high computational complexity. In this paper, we propose an efficient quadrature demodulation method for B-mode and color flow imaging, in which the RF signal is demodulated by a pair of finite impulse response filters without mixing with the reference signal, to reduce the computational complexity. The proposed method was evaluated with simulation and in vivo experiments. From the simulation results, the proposed quadrature demodulation method produced similar normalized residual sum of squares (NRSS) and velocity profile compared with the conventional quadrature demodulation method. In the in vivo color flow imaging experiments, the time of the demodulation process was 5.66 ms and 3.36 ms, for the conventional method and the proposed method, respectively. These results indicated that the proposed method can maintain the performance of quadrature demodulation while reducing computational complexity.

关键词： B-mode ultrasound imaging     Color flow imaging     Quadrature demodulation     Finite impulse response filter    

HTML PDF 收藏

Urban constructed wetlands: Assessing ecosystem services and disservices for safe, resilient, and sustainable cities

《工程管理前沿（英文）》   页码 582-596 doi: 10.1007/s42524-023-0268-y

摘要： Climate change and rapid urbanization are pressing environmental and social concerns, with approximately 56% of the global population living in urban areas. This number is expected to rise to 68% by 2050, leading to the expansion of cities and encroachment upon natural areas, including wetlands, causing their degradation and fragmentation. To mitigate these challenges, green and blue infrastructures (GBIs), such as constructed wetlands, have been proposed to emulate and replace the functions of natural wetlands. This study evaluates the potential of eight constructed wetlands near Beijing, China, focusing on their ecosystem services (ESs), cost savings related to human health, growing/maintenance expenses, and disservices using an emergy-based assessment procedure. The results indicate that all constructed wetlands effectively purify wastewater, reducing nutrient concentrations (e.g., total nitrogen, total phosphorus, and total suspended solids). Among the studied wetlands, the integrated vertical subsurface flow constructed wetland (CW-4) demonstrates the highest wastewater purification capability (1.63E+14 sej/m2/yr) compared to other types (6.78E+13 and 2.08E+13 sej/m2/yr). Additionally, constructed wetlands contribute to flood mitigation, groundwater recharge, wildlife habitat protection, and carbon sequestration, resembling the functions of natural wetlands. However, the implementation of constructed wetlands in cities is not without challenges, including greenhouse gas emissions, green waste management, mosquito issues, and disturbances in the surrounding urban areas, negatively impacting residents. The ternary phase diagram reveals that all constructed wetlands provide more benefits than costs and impacts. CW-4 shows the highest benefit‒cost ratio, reaching 50%, while free water surface constructed wetland (CW-3) exhibits the lowest benefits (approximately 38%), higher impacts (approximately 25%), and lower costs (approximately 37%) compared to other wetlands. The study advocates the use of an emergy approach as a reliable method to assess the quality of constructed wetlands, providing valuable insights for policymakers in selecting suitable constructed wetlands for effective urban ecological management.

关键词： constructed wetland     emergy     ecosystem services     disservices     ternary diagram    

HTML PDF 收藏

Study on wave rotor refrigerators

Yuqiang DAI, Dapeng HU, Meixia DING

《化学科学与工程前沿（英文）》 2009年 第3卷 第1期   页码 83-87 doi: 10.1007/s11705-009-0075-y

摘要： As a novel generation of a rotational gas wave machine, the wave rotor refrigerator (WRR) is an unsteady flow device used for refrigeration, in whose passages pressured streams directly contact and exchange energy due to the movement of pressure waves. In this paper, the working mechanism and refrigeration principle are investigated based on the one-dimensional unsteady flow theory. A basic limitation on main structural parameters and operating parameters is deduced and the wave diagram of WRR to guide designing is sketched. The main influential factors are studied through an experiment. In the DUT Gas Wave Refrigeration Studying and Development Center (GWRSDC) lab, the isentropic efficiency can now reach about 65%. The results show that the WRR is a feasible and promising technology in pressured gas refrigeration cases.

关键词： wave rotor     refrigeration     unsteady flow theory     wave diagram    

HTML PDF 收藏

Acoustic characteristics of bi-directional turbines for thermoacoustic generators

Dongdong LIU, Yanyan CHEN, Wei DAI, Ercang LUO

《能源前沿（英文）》 2022年 第16卷 第6期   页码 1027-1036 doi: 10.1007/s11708-020-0702-3

摘要： Bi-directional turbines combined with rotary motors may be a feasible option for developing high power thermoacoustic generators with low cost. A general expression for the acoustic characteristics of the bi-directional turbine was proposed based on theoretical derivation, which was validated by computational fluid dynamics modeling of an impulse turbine with fixed guide vanes. The structure of the turbine was optimized primarily using steady flow with an efficiency of near 70% (the shaft power divided by the total energy consumed by the turbine). The turbine in the oscillating flow was treated in a lumped-parameter model to extract the acoustic impedance characteristics from the simulation results. The key acoustic impedance characteristic of the turbine was the resistance and inertance due to complex flow condition in the turbine, whereas the capacitance was treated as an adiabatic case because of the large-scale flow channel relative to the heat penetration depth. Correlations for the impedance were obtained from both theoretical predictions and numerical fittings. The good fit of the correlations shows that these characteristics are valid for describing the bi-directional turbine, providing the basis for optimization of the coupling between the thermoacoustic engine and the turbine using quasi-one-dimensional theory in the frequency domain.

关键词： thermoacoustic power generator     acoustic characteristics     bi-directional impulse turbine     energy conversion    

HTML PDF 收藏

Deviation correction strategy for the earth pressure balance shield based on shield–soil interactions

《机械工程前沿（英文）》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0676-4

摘要： The control system presently used in shield posture rectification is based on driver experience, which is marginally reliable. The study of the related theory is flawed. Therefore, a decision-making approach for the deviation correction trajectory and posture rectification load for an earth pressure balance (EPB) shield is proposed. A calculation model of posture rectification load of an EPB shield is developed by considering the interactions among the cutter head, shield shell, and ground. The additional position change during the shield attitude correction is highlighted. The posture rectification loads and shield behaviors results can be solved by the proposed method. The influences of the stratum distribution (i.e., bedrock height in the upper-soft and lower-hard strata) on shield behaviors and posture rectification loads are analyzed. Results indicated that the increase of pitch angle in the upper-soft and lower-hard strata causes a sharp rise in vertical displacement. The bedrock height increases the magnitudes of the required posture rectification moments when hr/D > 0.5. For a tunnel with hr/D ≤ 0.5, the variation of hr/D has little effect on the posture rectification moments. Finally, the posture rectifying curves based on the theoretical model are compared with the target ones based on the double circular arc interpolation method. The required results can be obtained regardless of the soil–rock compound stratum distribution. The maximum rectification moment in the rock layer is almost 12.6 times that in the soil layer. Overall, this study provides a valuable reference for moment determination and the trajectory prediction of posture rectification in compound strata.

关键词： additional position change     deviation correction trajectory     earth pressure balance shield     mechanical model     posture rectification    

HTML PDF 收藏

Combustion instability detection using the wavelet detail of pressure fluctuations

JI Junjie, LUO Yonghao

《能源前沿（英文）》 2008年 第2卷 第1期   页码 116-120 doi: 10.1007/s11708-008-0019-0

摘要： A combustion instability detection method that uses the wavelet detail of combustion pressure fluctuations is put forward. To confirm this method, combustion pressure fluctuations in a stoker boiler are recorded at stable and unstable combustion with a pressure transducer. Daubechies one-order wavelet is chosen to obtain the wavelet details for comparison. It shows that the wavelet approximation indicates the general pressure change in the furnace, and the wavelet detail magnitude is consistent with the intensity of turbulence and combustion noise. The magnitude of the wavelet detail is nearly constant when the combustion is stable, however, it will fluctuate much when the combustion is unstable.

关键词： comparison     wavelet approximation     pressure transducer     general pressure     consistent    

HTML PDF 收藏

Hydraulic fracturing pressure of concentric double-layered cylinder in cohesive soil

《结构与土木工程前沿（英文）》 2021年 第15卷 第4期   页码 937-947 doi: 10.1007/s11709-021-0754-4

摘要： This study aims to investigate hydrofracturing in double-layered soil through theoretical and experimental analysis, as multilayered soils where the difference in mechanical properties exists are generally encountered in practical engineering. First, an analytical solution for fracturing pressure in two different concentric regions of soil was presented based on the cavity expansion theory. Then, several triaxial hydraulic fracturing tests were carried out to validate the analytical solution. The comparison between the experimental and analytical results indicates the remarkable accuracy of the derived formula, and the following conclusions were also obtained. First, there is a linear relationship between the fracturing pressure and confining pressure in concentric double-layered cohesive soil. Second, when the internal-layer soil is softer than the external-layer soil, the presence of internal soil on the fracturing pressure approximately brings the weakening effect, and the greater strength distinction between the two layers, the greater the weakening effect. Third, when the internal-layer soil is harder than the external-layer soil, the existence of the internal-layer soil has a strengthening effect on the fracturing pressure regardless of the proportion of internal-layer soil. Moreover, the influence of strength distinction between the two layers on the fracturing pressure is significant when the proportion of internal-layer soil is less than half, while it’s limited when the proportion is more than half. The proposed solution is potentially useful for geotechnical problems involving aspects of cohesive soil layering in a composite formation.

关键词： hydraulic fracturing pressure     layered     cavity expansion theory     triaxial fracturing test     cohesive soil    

HTML PDF 收藏

“Partial pressures” of humid air in wide pressure and temperature ranges

Zidong WANG, Hanping CHEN, Shilie WENG

《能源前沿（英文）》 2013年 第7卷 第4期   页码 511-517 doi: 10.1007/s11708-013-0281-7

摘要： “Partial pressure” in humid air is a question very much concerned by scientists and no satisfactory answer has been found to date. This paper proposes a novel method to obtain the “partial pressures” of the water vapor and dry air in humid air. The results obtained by the proposed method are quite different from that obtained by Dalton’s partial pressure law. The fundamental behaviors of water vapor and dry air are studied in depth in wide pressure and temperature ranges. Semi-permeable membrane models are proposed and applied for both saturated and unsaturated humid air. “Improvement factors” are developed to quantitatively describe the magnitude of the interaction between dissimilar molecules. One discovery is that the “partial pressure” of the water vapor in saturated humid air equals , rather than ( · ) which was formerly believed. The other is that the interaction between dissimilar molecules may be omitted when temperature is above “cutting-off temperature” for unsaturated humid air. This paper satisfactorily answers the quest of “partial pressures” in humid air from a new perspective.

关键词： partial pressure     Dalton’s partial pressure law     humid air     saturated     unsaturated    

HTML PDF 收藏

Non-invasive continuous blood pressure monitoring: a review of current applications

null

《医学前沿（英文）》 2013年 第7卷 第1期   页码 91-101 doi: 10.1007/s11684-013-0239-5

摘要：

Blood pressure monitoring has come a long way from the initial observations made by Reverend Hales in the 18th century. There are none that deny the importance of monitoring perioperative blood pressure; however, the limited ability of the current prevalent technology (oscillometric blood pressure monitoring) to offer continuous blood pressure measurements leaves room for improvement. Invasive monitoring is able to detect beat-to-beat blood pressure measurement, but the risks inherent to the procedure make it unsuitable for routine use except when this risk is outweighed by the benefits. This review focuses on the discoveries which have led up to the current blood pressure monitoring technologies, and especially the creation of those offering non-invasive but continuous blood pressure monitoring capabilities, including their methods of measurement and limitations.

关键词： non-invasive blood pressure monitoring     continuous blood pressure monitoring     invasive blood pressure monitoring     Riva-Rocci technique     oscillometric     Pe?áz technique     arterial tonometry     pulse transit time    

HTML PDF 收藏

Upper bound solution to seismic active earth pressure of submerged backfill subjected to partial drainage

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1480-1493 doi: 10.1007/s11709-021-0776-y

摘要： In waterfront geotechnical engineering, seismic and drainage conditions must be considered in the design of retaining structures. This paper proposes a general analytical method to evaluate the seismic active earth pressure on a retaining wall with backfill subjected to partial steady seepage flow under seismic conditions. The method comprises the following steps: i) determination of the total head, ii) upper bound solution of seismic active earth thrust, and iii) deduction for the earth pressure distribution. The determination of total head h(x,z) relies on the Fourier series expansions, and the expressions of the seismic active earth thrust and pressure are derived by using the upper bound theorem. Parametric studies reveal that insufficient drainage and earthquakes are crucial factors that cause unfavorable earth pressure. The numerical results confirm the validity of the total head distribution. Comparisons indicate that the proposed method is consistent with other relevant existing methods in terms of predicting seismic active earth pressure. The method can be applied to the seismic design of waterfront retaining walls.

关键词： seismic active earth pressure     partial seepage flow     pore pressure     anisotropy     upper bound theorem    

HTML PDF 收藏

Assessment and validation of liquid breakup models for high-pressure dense diesel sprays

Yi REN,Xianguo LI

《能源前沿（英文）》 2016年 第10卷 第2期   页码 164-175 doi: 10.1007/s11708-016-0407-9

摘要： Liquid breakup in fuel spray and atomization significantly affects the consequent mixture formation, combustion behavior, and emission formation processes in a direct injection diesel engine. In this paper, different models for liquid breakup processes in high-pressure dense diesel sprays and its impact on multi-dimensional diesel engine simulation have been evaluated against experimental observations, along with the influence of the liquid breakup models and the sensitivity of model parameters on diesel sprays and diesel engine simulations. It is found that the modified Kelvin-Helmholtz (KH)–Rayleigh-Taylor (RT) breakup model gives the most reasonable predicted results in both engine simulation and high-pressure diesel spray simulation. For the standard KH-RT model, the model constant for the breakup length has a significant effect on the predictability of the model, and a fixed value of the constant cannot provide a satisfactory result for different operation conditions. The Taylor-analogy-breakup (TAB) based models and the RT model do not provide reasonable predictions for the characteristics of high-pressure sprays and simulated engine performance and emissions.

关键词： breakup model     diesel engine     high-pressure injection     simulations    

HTML PDF 收藏

标题 作者 时间 类型 操作

Development of dimensionless P-I diagram for curved SCS sandwich shell subjected to uniformly distributedblast pressure

Yonghui WANG, Ximei ZHAI

期刊论文

完全信息价值的影响图求解法及其应用

刘艳琼,陈英武

期刊论文

Design and optimization of reactive distillation: a review

期刊论文

认知无线电网络中利用信道冲击响应的主用户仿真攻击检测技术

Qiao-mu JIANG, Hui-fang CHEN, Lei XIE, Kuang WANG

期刊论文

Anefficient quadrature demodulator for medical ultrasound imaging

Hao ZHOU,Yin-fei ZHENG

期刊论文

Urban constructed wetlands: Assessing ecosystem services and disservices for safe, resilient, and sustainable cities

期刊论文

Study on wave rotor refrigerators

Yuqiang DAI, Dapeng HU, Meixia DING

期刊论文

Acoustic characteristics of bi-directional turbines for thermoacoustic generators

Dongdong LIU, Yanyan CHEN, Wei DAI, Ercang LUO

期刊论文

Deviation correction strategy for the earth pressure balance shield based on shield–soil interactions

期刊论文

Combustion instability detection using the wavelet detail of pressure fluctuations

JI Junjie, LUO Yonghao

期刊论文

Hydraulic fracturing pressure of concentric double-layered cylinder in cohesive soil

期刊论文

“Partial pressures” of humid air in wide pressure and temperature ranges

Zidong WANG, Hanping CHEN, Shilie WENG

期刊论文

Non-invasive continuous blood pressure monitoring: a review of current applications

null

期刊论文

Upper bound solution to seismic active earth pressure of submerged backfill subjected to partial drainage

期刊论文

Assessment and validation of liquid breakup models for high-pressure dense diesel sprays

Yi REN,Xianguo LI

期刊论文