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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    

A novel intravenous general anesthetic--- emulsified isoflurane: from bench to bedside

null

《医学前沿(英文)》 2012年 第6卷 第4期   页码 381-387 doi: 10.1007/s11684-012-0229-z

摘要:

Application of volatile anesthetics greatly alters modern medicine. There are obvious advantages of volatile anesthetics such as strong anesthetic potency, rapid onset and elimination through respiration system. Isoflurane is one of the most widely used volatile anesthetics in clinic. Emulsified isoflurane, the emulsion of isoflurane, is a novel intravenous general anesthetic. With the development of emulsified isoflurane in the past fifteen years, its utility has spread from intravenous general anesthesia to various fields including regional anesthesia, organ protection, as well as anesthetic pharmacological study. In this review, we will summarize literatures of emulsified isoflurane about its history, clinical application and future potential utility in the above mentioned fields.

关键词: emulsified isoflurane (EI)     general anesthesia     regional anesthesia     organ protection     anesthetic pharmacological study    

Numerical investigation of circle defining curve for two-dimensional problem with general boundaries

Chung Nguyen VAN

《结构与土木工程前沿(英文)》 2019年 第13卷 第1期   页码 92-102 doi: 10.1007/s11709-018-0472-8

摘要: The scaled boundary finite element method (SBFEM) is applied to the static analysis of two dimensional elasticity problem, boundary value problems domain with the domain completely described by a circular defining curve. The scaled boundary finite element equations is formulated within a general framework integrating the influence of the distributed body force, general boundary conditions, and bounded and unbounded domain. This paper investigates the possibility of using exact geometry to form the exact description of the circular defining curve and the standard finite element shape function to approximate the defining curve. Three linear elasticity problems are presented to verify the proposed method with the analytical solution. Numerical examples show the accuracy and efficiency of the proposed method, and the performance is found to be better than using standard linear element for the approximation defining curve on the scaled boundary method.

关键词: exact geometry     circular defining curve     general boundaries     SBFEM    

coated on endotracheal tube with or without epidural lidocaine reduces isoflurane requirement during general

null

《医学前沿(英文)》 2012年 第6卷 第3期   页码 302-306 doi: 10.1007/s11684-012-0194-6

摘要:

This study was designed to evaluate the effect of tracheal topical anesthesia using EMLA? Cream (EC) coated on the endotracheal tube (ETT) with or without epidural anesthesia (EA) on isoflurane requirement during general anesthesia (GA) and investigate whether EC coated on the ETT with EA was associated with the additive effect compared with the effect when each anesthetic was administered independently. The prospective randomized, double-blinded, and controlled study included 60 ASA I–II patients scheduled for upper abdominal surgery requiring GA. Patients were randomly assigned to one of the following groups: group 1 received GA, group 2 received EC+ GA, group 3 received GA+ EA, and group 4 received EC+ GA+ EA. Isoflurane was administered at the required concentrations to maintain the mean arterial pressure at a level not exceeding 20% of preoperative values. The percentage mean expired concentration (%MEC) was used in calculating the isoflurane requirement. Emergence agitation, postoperative sore throat, and hoarseness were recorded. Groups 2, 3, and 4 exhibited a significant reduction on isoflurane requirement compared with group 1 (P<0.05). The isoflurane requirement evaluated by %MEC decreased by 12%, 38%, and 50% in groups 2, 3, and 4, respectively. The incidence of emergence agitation was significantly lower in groups 2 and 4 than those in groups 1 and 3 (P<0.05). Tracheal topical anesthesia using EC coated on ETT with or without EA reduced the isoflurane requirement during GA, indicating that EC combined with EA exhibited an additive effect on the requirement of general anesthetic.

关键词: EMLA? Cream     epidural anesthesia     general anesthesia     isoflurane     lidocaine    

The next step of community health construction: Training general practitioners and implementing health

Kan ZHANG MM, Wei DONG MM, Ying-Yao CHEN MD,

《医学前沿(英文)》 2010年 第4卷 第2期   页码 134-138 doi: 10.1007/s11684-010-0041-6

摘要: This article discusses the concept of health management and stresses that community health management should be the starting point of community health service, necessitating a paradigm shift from observing the treatment-oriented medical model to observing the prevention-and-health management-based medical model. Community health construction has entered a new phase, one which highlights the need to train general practitioners in practice-based life cycle health management. In addition, general practitioners should assume the mission of implementing community health management.

关键词: community health     general practitioners     health management    

声学综合无损检测技术

陈积懋

《中国工程科学》 2000年 第2卷 第4期   页码 64-69

摘要:

论述了检测复合材料和胶接结构不连续(缺陷)的新型多模综合无损检测技术。该技术以声与超声检测技术为基础,包含五种不同检测模式,用以检测复合材料与胶接结构的失粘、脱粘、分层、疏松、夹芯压皱及其他缺陷。它适用于复合材料与构件的制造、维修和使用现场。它的适用对象范围广泛,几乎覆盖了现有常用的复合材料和胶接结构。它的检测可靠性高,重复精度好。文章还讨论了组成多膜声学综合胶接检测仪的五种不同检测模式的原理,并从我们和国内外同行的大量实践经验出发,说明了综合无损检测技术的巨大发展前景。

关键词: 声学综合检测     综合无损检测     复合材料无损检测     机械阻抗分析     振动分析     共振检测    

General modeling and optimization technique for real-world earth observation satellite scheduling

《工程管理前沿(英文)》   页码 695-709 doi: 10.1007/s42524-023-0263-3

摘要: Over the last two decades, many modeling and optimization techniques have been developed for earth observation satellite (EOS) scheduling problems, but few of them show good generality to be engineered in real-world applications. This study proposes a general modeling and optimization technique for common and real-world EOS scheduling cases; it includes a decoupled framework, a general modeling method, and an easy-to-use algorithm library. In this technique, a framework that decouples the modeling, constraints, and optimization of EOS scheduling problems is built. With this framework, the EOS scheduling problems are appropriately modeled in a general manner, where the executable opportunity, another format of the well-known visible time window per EOS operation, is viewed as a selectable resource to be optimized. On this basis, 10 types of optimization algorithms, such as Tabu search and genetic algorithm, and a parallel competitive memetic algorithm, are developed. For simplified EOS scheduling problems, the proposed technique shows better performance in applicability and effectiveness than the state-of-the-art algorithms. In addition, a complicatedly constrained real-world benchmark exampled by a four-EOS Chinese commercial constellation is provided, and the technique is qualified and outperforms the in-use scheduling system by more than 50%.

关键词: earth observation satellite     scheduling     general technique     optimization algorithm     commercial constellation     real-world     benchmark    

Feasible workspace regions for general two-revolute manipulator

Conghui LIANG, Marco CECCARELLI

《机械工程前沿(英文)》 2011年 第6卷 第4期   页码 397-408 doi: 10.1007/s11465-011-0228-9

摘要:

In this paper, a topology is presented for feasible workspace regions in general two-revolute manipulators. The design problem and concept of feasible workspace regions have been discussed as linked to each other. Design equations are formulated by arbitrarily prescribing four workspace boundary points. The so-called feasible workspace regions are the intersection of three different sub-regions, which are given by constraint curves as function of the relative positions of three workspace boundary points. By using a parametric study, all topologies for three sub-regions are figured out. Corresponding areas in cross section plane are determined for prescribing the position of a feasible workspace point as function of the topology for sub-regions. A classification has been proposed to determine and to characterize the combination of the topologies for those sub-regions. All topologies for feasible workspace regions are figured out and they are discussed as a design tool. Three general cases are analyzed in details to characterize workspace design capabilities for general two-revolute manipulators.

关键词: workspace     two-revolute manipulators     topology analysis     design    

General framework for bridge life cycle design

Junhai MA, Airong CHEN, Jun HE

《结构与土木工程前沿(英文)》 2009年 第3卷 第1期   页码 50-56 doi: 10.1007/s11709-009-0004-7

摘要: Based on a detailed illustration for bridge life cycle design which comprises the processes of service life design, aesthetics design, performance design, environmental and ecological design, inspection, maintenance and repair design as well as cost analysis, this paper presented a general framework for bridge life cycle design comprising three design phases and six design processes.

关键词: bridge whole life design     design phase     design process     general framework    

卫星移动网络总体概念设计仿真

金士尧

《中国工程科学》 2004年 第6卷 第1期   页码 30-36

摘要:

卫星移动网络是以卫星星座为基本物理架构,通过星际的通信链路形成覆盖全球的天基通信网络。它对社会发展、科技进步以及军队的信息化有着重大的推动作用。由于天网的移动性、通信的偶断性、接入的复杂性以及使用的综合性,都为研制提出了重大的挑战。有必要通过总体概念设计仿真,来进一步验证总体需求、总体方案、关键技术指标和研制的约束条件,形成科学的可行性报告。介绍了卫星移动网络的总体概念,设计了针对天网仿真的平台,并用实例获得卫星移动网络总体概念设计的仿真数据。

关键词: 卫星移动网络     总体     仿真    

pulse oximetry is more accurate and detects hypoxemia earlier than conventional pulse oximetry during general

null

《医学前沿(英文)》 2012年 第6卷 第4期   页码 406-410 doi: 10.1007/s11684-012-0217-3

摘要:

The esophagus is perfused directly by prominent arteries and may provide a more consistent tissue source for pulse oximetry. The goal of this study was to evaluate the sensitivity and accuracy of an esophageal pulse oximetry probe on patients during controlled hypoxemia in comparison to measurements obtained with conventional pulse oximetry (SpulseO2). Forty-five ASA I–II adult patients were included in this prospective observational study. Nellcor digital oximetric probes were placed on finger tips for SpulseO2 before anesthesia. After tracheal intubation, an esophageal probe was placed in the lower segment of the esophagus for esophageal oximetric monitoring (SoesO2). All patients were disconnected from the breathing circuit to establish a controlled hypoxemia, and were re-connected to the breathing circuit and ventilated with 100% oxygen immediately when SoesO2 dropped to 90%. Matched SoesO2 and SpulseO2 readings were recorded when SoesO2measurements were at 100%, 95%, 90% and the lowest reading. The time for SoesO2 and SpulseO2 to drop from 100% to 95%, 90% and return to 100% was recorded. Oxygen saturation from arterial blood samples (SartO2) was also measured at each time point respectively. The linear correlation coefficient of the regression analysis between SartO2 and SoesO2 was 0.954. The mean±2SD of the difference was 0.3%±4.3% for SoesO2vs. SartO2 and 6.8%±5.6% for SpulseO2vs. SartO2 (P<0.001). The 95% confidence interval for the absolute difference between SoesO2 and SartO2 was 0.3% to 0.7% and 6.2% to 7.4% between SpulseO2 and SartO2. The time to reach 90% saturation measured with SoesO2 was approximately 94 seconds earlier than the SpulseO2 (P<0.001). In conclusion, SoesO2 is more accurate and enables earlier detection of hypoxemia when compared to conventional pulse oximetry during hypoxemia for patients undergoing general anesthesia.

关键词: esophageal pulse oximetry     conventional pulse oximetry     hypoxemia    

我国全科医生培养现状与发展策略

刘颖,蒋国平,任菁菁

《中国工程科学》 2019年 第21卷 第2期   页码 74-78 doi: 10.15302/J-SSCAE-2019.02.005

摘要:

经过近30年的不断探索和实践,我国全科医生队伍建设取得了一定的进展,初步建立了以“5+3”为主、“3+2”为辅的全科医生培养模式,但我国仍面临严重缺乏合格全科医生的情况。本文通过对我国全科医生培养现状的研究,了解到当前我国全科医生岗位缺乏吸引力,全科医生培养制度和体系不够完善,缺乏完善的过程考核机制,住培基地准入和再认证机制不完善,持续职业发展教育亟待规范。通过对国际上主要国家发展全科医生经验的回顾研究,建议我国应当切实提升全科医生待遇;以“岗位胜任力”为导向,建立完善的全科医生培训过程考核体系;统一全科医生住培基地准入条件,建立常态化基地评估认证机制;设置全科持续职业发展教育基地。

关键词: 全科医生     人才培养     岗位胜任力    

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    

Effects of intracerebroventricular NMDA and non-NMDA receptor agonists or antagonists on general anesthesia

XU Aijun, TIAN Yuke, DUAN Shiming

《医学前沿(英文)》 2007年 第1卷 第2期   页码 207-210 doi: 10.1007/s11684-007-0039-x

摘要: The effects of intracerebroventricular (icv) agonists and antagonists of -methyl--aspartate (NMDA) and alpha-amino-3-hydroxy 5-methyl-4-isoxazole-propionic acid (AMPA) receptors on the general anesthesia of propofol were studied. A total of 144 Kunming mice, male and female with body mass of (22?3) g, were used. Part One of the Experiment: a total of 104 Kunming mice, male and female, were randomly divided into 13 groups. Intracerebroventricular artificial cerebral fluid (aCSF) or different doses of NMDA, AMPA, MK-801 or NBQX was injected immediately after intravenously administered propofol 25 mg/kg and the recovery time following the loss of righting reflex (LORR) was recorded. Part Two of the Experiment: a total of 40 Kunming female mice were divided randomly into 5 groups and injected with icv aCSF or NMDA, AMPA, MK-801 or NBQX after intraperitoneally administered propofol 50 mg/kg. The pain threshold of the mice was then investigated by hot-plate test (HPPT). NMDA (0.05 or 0.075?g, icv) or AMPA (0.05 ?g, icv) exhibited no effects on the LORR, but NMDA (0.1 μg, icv) or AMPA (0.075 or 0.1 ?g, icv) prolonged the LORR significantly compared with the aCSF group (<0.05, <0.01). The LORR of the 2 μg MK-801 group had no changes, while those of the 4 or 8 μg MK-801 groups were prolonged significantly. The LORR of the 0.5, 2 or 4 μg NBQX groups were all prolonged significantly. NMDA 0.05 ?g or AMPA 0.05 ?g decreased the pain threshold slightly but did not differ in effect compared with the aCSF group; 2 μg MK-801 or 0.5 μg NBQX both increased the pain threshold significantly. Our results indicate that propofol produces general anesthesia partly through an interaction with brain NMDA and AMPA receptors in mice.

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    

标题 作者 时间 类型 操作

Combustion instability detection using the wavelet detail of pressure fluctuations

JI Junjie, LUO Yonghao

期刊论文

A novel intravenous general anesthetic--- emulsified isoflurane: from bench to bedside

null

期刊论文

Numerical investigation of circle defining curve for two-dimensional problem with general boundaries

Chung Nguyen VAN

期刊论文

coated on endotracheal tube with or without epidural lidocaine reduces isoflurane requirement during general

null

期刊论文

The next step of community health construction: Training general practitioners and implementing health

Kan ZHANG MM, Wei DONG MM, Ying-Yao CHEN MD,

期刊论文

声学综合无损检测技术

陈积懋

期刊论文

General modeling and optimization technique for real-world earth observation satellite scheduling

期刊论文

Feasible workspace regions for general two-revolute manipulator

Conghui LIANG, Marco CECCARELLI

期刊论文

General framework for bridge life cycle design

Junhai MA, Airong CHEN, Jun HE

期刊论文

卫星移动网络总体概念设计仿真

金士尧

期刊论文

pulse oximetry is more accurate and detects hypoxemia earlier than conventional pulse oximetry during general

null

期刊论文

我国全科医生培养现状与发展策略

刘颖,蒋国平,任菁菁

期刊论文

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

期刊论文

Effects of intracerebroventricular NMDA and non-NMDA receptor agonists or antagonists on general anesthesia

XU Aijun, TIAN Yuke, DUAN Shiming

期刊论文

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

期刊论文