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Improvement of part-load performance of gas turbine by adjusting compressor inlet air temperature and IGV opening

《能源前沿（英文）》 2022年 第16卷 第6期   页码 1000-1016 doi: 10.1007/s11708-021-0746-z

摘要： A novel adjusting method for improving gas turbine (GT) efficiency and surge margin (SM) under part-load conditions is proposed. This method adopts the inlet air heating technology, which uses the waste heat of low-grade heat source and the inlet guide vane (IGV) opening adjustment. Moreover, the regulation rules of the compressor inlet air temperature and the IGV opening are studied comprehensively to optimize GT performance. A model and calculation method for an equilibrium running line is adopted based on the characteristic curves of the compressor and turbine. The equilibrium running lines calculated through the calculation method involve three part-load conditions and three IGV openings with different inlet air temperatures. The results show that there is an optimal matching relationship between IGV opening and inlet air temperature. For the best GT performance of a given load, the IGV could be adjusted according to inlet air temperature. In addition, inlet air heating has a considerable potential for the improvement of part-load performance of GT due to the increase in compressor efficiency, combustion efficiency, and turbine efficiency as well as turbine inlet temperature, when inlet air temperature is lower than the optimal value with different IGV openings. Further, when the IGV is in a full opening state and an optimal inlet air temperature is achieved by using the inlet air heating technology, GT efficiency and SM can be obviously higher than other IGV openings. The IGV can be left unadjusted, even when the load is as low as 50%. These findings indicate that inlet air heating has a great potential to replace the IGV to regulate load because GT efficiency and SM can be remarkably improved, which is different from the traditional viewpoints.

关键词： inlet air temperature     inlet guide vane (IGV) opening     part-load     equilibrium running line     gas turbine (GT) efficiency     surge margin (SM)    

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Stability and agility: biped running over varied and unknown terrain

Yang YI,Zhi-yun LIN

《信息与电子工程前沿（英文）》 2015年 第16卷 第4期   页码 283-292 doi: 10.1631/FITEE.1400284

摘要： We tackle the problem of a biped running over varied and unknown terrain. Running is a necessary skill for a biped moving fast, but it increases the challenge of dynamic balance, especially when a biped is running on varied terrain without terrain information (due to the difficulty and cost of obtaining the terrain information in a timely manner). To address this issue, a new dynamic indicator called the sustainable running criterion is developed. The main idea is to sustain a running motion without falling by maintaining the system states within a running-feasible set, instead of running on a periodic limit cycle gait in the traditional way. To meet the precondition of the criterion, the angular moment about the center of gravity (COG) is restrained close to zero at the end of the stance phase. Then to ensure a small state jump at touchdown on the unknown terrain, the velocity of the swing foot is restrained within a specific range at the end of the flight phase. Finally, the position and velocity of the COG are driven into the running-feasible set. A five-link biped with underactuated point foot is considered in simulations. It is able to run over upward and downward terrain with a height difference of 0.15 m, which shows the effectiveness of our control scheme.

关键词： Underactuated running biped     Dynamic balance     Varied and unknown terrain    

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Analysis on running safety of train on the bridge considering sudden change of wind load caused by wind

Tian ZHANG, He XIA, Weiwei GUO

《结构与土木工程前沿（英文）》 2018年 第12卷 第4期   页码 558-567 doi: 10.1007/s11709-017-0455-1

摘要： The calculation formulae for change of wind load acting on the car-body are derived when a train moves into or out of the wind barrier structure, the dynamic analysis model of wind-vehicle-bridge system with wind barrier is established, and the influence of sudden change of wind load on the running safety of the train is analyzed. For a 10-span simply-supported U-shaped girder bridge with 100 m long double-side 3.5 m barrier, the response and the running safety indices of the train are calculated. The results are compared with those of the case with wind barrier on the whole bridge. It is shown that the sudden change of wind load caused by wind barrier has significant influence on the lateral acceleration of the car-body, but no distinct on the vertical acceleration. The running safety indices of train vehicle with sectional wind barriers are worse than those with full wind barriers, and the difference increases rapidly with wind velocity.

关键词： wind barrier     sudden change of wind load     dynamic response     running safety     comfort    

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Thermodynamic analysis of reaction pathways and equilibrium yields for catalytic pyrolysis of naphtha

《化学科学与工程前沿（英文）》 2022年 第16卷 第12期   页码 1700-1712 doi: 10.1007/s11705-022-2207-6

摘要： The chain length and hydrocarbon type significantly affect the production of light olefins during the catalytic pyrolysis of naphtha. Herein, for a better catalyst design and operation parameters optimization, the reaction pathways and equilibrium yields for the catalytic pyrolysis of C5–8 n/iso/cyclo-paraffins were analyzed thermodynamically. The results revealed that the thermodynamically favorable reaction pathways for n/iso-paraffins and cyclo-paraffins were the protolytic and hydrogen transfer cracking pathways, respectively. However, the formation of light paraffin severely limits the maximum selectivity toward light olefins. The dehydrogenation cracking pathway of n/iso-paraffins and the protolytic cracking pathway of cyclo-paraffins demonstrated significantly improved selectivity for light olefins. The results are thus useful as a direction for future catalyst improvements, facilitating superior reaction pathways to enhance light olefins. In addition, the equilibrium yield of light olefins increased with increasing the chain length, and the introduction of cyclo-paraffin inhibits the formation of light olefins. High temperatures and low pressures favor the formation of ethylene, and moderate temperatures and low pressures favor the formation of propylene. n-Hexane and cyclohexane mixtures gave maximum ethylene and propylene yield of approximately 49.90% and 55.77%, respectively. This work provides theoretical guidance for the development of superior catalysts and the selection of proper operation parameters for the catalytic pyrolysis of C5–8 n/iso/cyclo-paraffins from a thermodynamic point of view.

关键词： naphtha     catalytic pyrolysis     reaction pathway     equilibrium yield    

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破纪录的黑科技跑鞋

Chris Palmer

《工程（英文）》 2020年 第6卷 第9期   页码 962-963 doi: 10.1016/j.eng.2020.07.006

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余弦忆导忆阻系统周期变化初值位移调控行为 Regular Papers

Mo CHEN, Xue REN, Hua-gan WU, Quan XU, Bo-cheng BAO

《信息与电子工程前沿（英文）》 2019年 第20卷 第12期   页码 1706-1716 doi: 10.1631/FITEE.1900360

摘要： 利用一种新型余弦忆导理想忆阻，构造一个四维忆阻系统。由于忆导函数特殊的非线性，忆阻系统具有沿忆阻内部状态变量坐标轴分布的线平衡点集(0, 0, 0, δ)，且平衡点集稳定性随δ变化而周期性演化。数值仿真揭示了忆阻系统非线性、一维的初值位移调控行为，它不仅可由忆阻状态初值触发，也可由其他两个系统状态初值引发。特别地，在位移调控路线上，可以观测到多种具有不同位置和拓扑结构的共存吸引子。通过PSIM电路仿真对该特殊动力学特性进行了验证。

关键词： 初值位移调控；忆阻系统；忆导；线平衡点集    

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Dynamic response of a long span suspension bridge and running safety of a train under wind action

GUO Weiwei, XIA He, XU You-lin

《结构与土木工程前沿（英文）》 2007年 第1卷 第1期   页码 71-79 doi: 10.1007/s11709-007-0007-1

摘要： A dynamic analysis model of a wind-train-bridge system is established. The wind excitations of the system are the buffeting and self-excited forces simulated in time domain using measured aerodynamic coefficients and flutter derivatives. The proposed formulations are then applied to a long rail-cum-road suspension bridge. The dynamic responses of the bridge and the train under wind action are analyzed. The results show that the lateral and rotational displacements of the bridge are dominated by wind, while the vertical by the gravity loading of the moving train. The running safeties of the train vehicles are much affected by wind. Under wind conditions of 30 40 m/s, the offload factors, derail factors and overturn factors of the train vehicles exceed the safety allowances, to which great attention should be paid.

关键词： rotational     offload     vertical     m/s     attention    

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Measurement and correlation of the solid-liquid equilibrium of 2-(

Yanhong SUN, Zhiyong LI, Chuang XIE, Wei CHEN, Cui ZHANG

《化学科学与工程前沿（英文）》 2013年 第7卷 第1期   页码 110-115 doi: 10.1007/s11705-013-1316-7

摘要： In this work, the enthalpy of fusion and melting points of 2-( -butyl)-5-methylphenol (2B5MP) and 2-( -butyl)-4-methylphenol (2B4MP) were measured by differential scanning calorimetry (DSC). The binary solid-liquid equilibrium (SLE) of both compounds were predicted by integrated computer aided system (ICAS) and measured by DSC. The corresponding eutectic molar composition is 0.6998 and the eutectic temperature is 281.96 K. The quasi-static heat capacities of 2B5MP and 2B4MP were evaluated by stochastic temperature modulation DSC technique (TOPEM). The SLE experimental data were correlated using the Margules, Wilson, and non-random two liquid (NRTL) equations and a good agreement between measurement and calculation could be obtained.

关键词： solid-liquid equilibrium (SLE)     eutectic     integrated computer aided system (ICAS)     TOPEM     correlation    

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Acoustic fault signal extraction via the line-defect phononic crystals

《机械工程前沿（英文）》 2022年 第17卷 第1期   页码 10-10 doi: 10.1007/s11465-021-0666-y

摘要： Rotating machine fault signal extraction becomes increasingly important in practical engineering applications. However, fault signals with low signal-to-noise ratios (SNRs) are difficult to extract, especially at the early stage of fault diagnosis. In this paper, 2D line-defect phononic crystals (PCs) consisting of periodic acrylic tubes with slit are proposed for weak signal detection. The defect band, namely, the formed resonance band of line-defect PCs enables the incident acoustic wave at the resonance frequency to be trapped and enhanced at the resonance cavity. The noise can be filtered by the band gap. As a result, fault signals with high SNRs can be obtained for fault feature extraction. The effectiveness of weak harmonic and periodic impulse signal detection via line-defect PCs are investigated in numerical and experimental studies. All the numerical and experimental results indicate that line-defect PCs can be well used for extracting weak harmonic and periodic impulse signals. This work will provide potential for extracting weak signals in many practical engineering applications.

关键词： phononic crystals     line-defect     fault signal extraction     acoustic enhancement    

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Brown marine algae turbinaria conoides as biosorbent for Malachite green removal: Equilibrium and kinetic

R. RAJESH KANNAN, M. RAJASIMMAN, N. RAJAMOHAN, B. SIVAPRAKASH,

《环境科学与工程前沿（英文）》 2010年 第4卷 第1期   页码 116-122 doi: 10.1007/s11783-010-0006-7

摘要： In this study, the biosorption of Malachite green (MG) onto Turbinaria conoides, brown marine algae, was studied with respect to initial pH, temperature, initial dye concentration, and sorbent dosage. The optimum initial pH and temperature values for MG removal were found to be 8.0 and 30°C, respectively. Sorbent dosage was found to strongly influence the removal of MG. Equilibrium studies were carried out to test the validity of the Langmuir ( = 66.6 mg/g and = 0.526 mL mol/L) and the Freundlich ( = 1.826 and = 3.751 mg/g) isotherms. The kinetic studies indicated the validity of the pseudo first-order and second-order equation.

关键词： Malachite green (MG)     Turbinaria conoides     marine algae     equilibrium studies     biosorption    

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Calculations of narrow-band transimissities and the Planck mean absorption coefficients of real gases using line-by-line

Huaqiang CHU, Mingyan GU, Huaichun ZHOU, Fengshan LIU

《能源前沿（英文）》 2014年 第8卷 第1期   页码 41-48 doi: 10.1007/s11708-013-0292-4

摘要： Narrow-band transmissivities in the spectral range of 150 to 9300 cm and at a uniform resolution of 25 cm were calculated using the statistical narrow-band (SNB) model with the band parameters of Soufiani and Taine, the more recent parameters of André and Vaillon, and the line-by-line (LBL) method along with the HITEMP-2010 spectroscopic database. Calculations of narrow-band transmissivity were conducted for gas columns of different lengths and containing different isothermal and non-isothermal CO -H O-N mixtures at 1 atm. Narrow-band transmissivities calculated by the SNB model are in large relative error at many bands. The more recent SNB model parameters of André and Vaillon are more accurate than the earlier parameters of Soufiani and Taine. The Planck mean absorption coefficients of CO , H O, CO, and CH in the temperature range of 300 to 2500 K were calculated using the LBL method and different versions of the high resolution transmission (HITRAN) and high-temperature spectroscopic absorption parameters (HITEMP) spectroscopic databases. The SNB model was also used to calculate the Planck mean absorption coefficients of these four radiating gases. The LBL results of the Planck mean absorption coefficient were compared with the classical results of Tien and those from the SNB model.

关键词： transimissity     HITEMP     HITRAN     Planck mean absorption coefficients    

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Non-equilibrium model for catalytic distillation process

WANG Feng, ZHAO Ning, LI Junping, XIAO Fukui, WEI Wei, SUN Yuhan

《化学科学与工程前沿（英文）》 2008年 第2卷 第4期   页码 379-384 doi: 10.1007/s11705-008-0071-7

摘要： A new improved tri-diagonal method was developed for the non-equilibrium stage model of the catalytic distillation by coupling consumptive reaction coefficient. The reactions in the distillation column were divided into generative reaction and consumptive reaction. The non-equilibrium stage model was introduced for the catalytic distillation process of the dimethyl carbonate (DMC) synthesis by urea methanolysis over solid based catalyst, and the improved tri-diagonal method was used to solve the model equations. Comparison of predicted results with experiment data shows that the mean relative error of the yield of DMC was 3.78% under different conditions such as different operating pressures and reaction temperatures. The improved tri-diagonal matrix method could avoid the negative values of the liquid compositions during the calculations and restrain the fluctuation of compositions by slowing down the variations of the values in the iteration. The modeling results show that the improved tri-diagonal method was appropriate for system containing a wide range of boiling point components and a different rate of reactions.
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Pareto lexicographic α-robust approach and its application in robust multi objective assembly line balancing

null

《机械工程前沿（英文）》 2014年 第9卷 第3期   页码 257-264 doi: 10.1007/s11465-014-0294-x

摘要：

Robustness in most of the literature is associated with min-max or min-max regret criteria. However, these criteria of robustness are conservative and therefore recently new criteria called, lexicographic α-robust method has been introduced in literature which defines the robust solution as a set of solutions whose quality or jth largest cost is not worse than the best possible jth largest cost in all scenarios. These criteria might be significant for robust optimization of single objective optimization problems. However, in real optimization problems, two or more than two conflicting objectives are desired to optimize concurrently and solution of multi objective optimization problems exists in the form of a set of solutions called Pareto solutions and from these solutions it might be difficult to decide which Pareto solution can satisfy min-max, min-max regret or lexicographic α-robust criteria by considering multiple objectives simultaneously. Therefore, lexicographic α-robust method which is a recently introduced method in literature is extended in the current research for Pareto solutions. The proposed method called Pareto lexicographic α-robust approach can define Pareto lexicographic α-robust solutions from different scenarios by considering multiple objectives simultaneously. A simple example and an application of the proposed method on a simple problem of multi objective optimization of simple assembly line balancing problem with task time uncertainty is presented to get their robust solutions. The presented method can be significant to implement on different multi objective robust optimization problems containing uncertainty.

关键词： Pareto     lexicographic α-robust     assembly line balancing    

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Machine learning for detecting mesial temporal lobe epilepsy by structural and functional neuroimaging

Baiwan Zhou, Dongmei An, Fenglai Xiao, Running Niu, Wenbin Li, Wei Li, Xin Tong, Graham J Kemp, Dong

《医学前沿（英文）》 2020年 第14卷 第5期   页码 630-641 doi: 10.1007/s11684-019-0718-4

摘要： Mesial temporal lobe epilepsy (mTLE), the most common type of focal epilepsy, is associated with functional and structural brain alterations. Machine learning (ML) techniques have been successfully used in discriminating mTLE from healthy controls. However, either functional or structural neuroimaging data are mostly used separately as input, and the opportunity to combine both has not been exploited yet. We conducted a multimodal ML study based on functional and structural neuroimaging measures. We enrolled 37 patients with left mTLE, 37 patients with right mTLE, and 74 healthy controls and trained a support vector ML model to distinguish them by using each measure and the combinations of the measures. For each single measure, we obtained a mean accuracy of 74% and 69% for discriminating left mTLE and right mTLE from controls, respectively, and 64% when all patients were combined. We achieved an accuracy of 78% by integrating functional data and 79% by integrating structural data for left mTLE, and the highest accuracy of 84% was obtained when all functional and structural measures were combined. These findings suggest that combining multimodal measures within a single model is a promising direction for improving the classification of individual patients with mTLE.

关键词： mesial temporal lobe epilepsy     functional magnetic resonance imaging     structural magnetic resonance imaging     machine learning     support vector machine    

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Choosing configurations of transmission line tower grounding by back flashover probability value

Dmitry KUKLIN

《能源前沿（英文）》 2016年 第10卷 第2期   页码 213-226 doi: 10.1007/s11708-016-0398-6

摘要： There is a considerable number of works devoted to electrical characteristics of grounding. These characteristics are important in general. However, in application to grounding of transmission line towers they are not enough to determine what grounding construction is preferable in some particular case, because these characteristics are calculated or measured apart from the grounded object, and only limited number of current (or voltage) source waveforms is used. This paper indicates reasons in favor of the fact that to choose the optimum design of grounding, the calculation model should include the tower as it is. The probability of back flashover, which provides both qualitative and quantitative estimate of the grounding structure efficiency, can be taken as the criterion for the grounding design. The insulation flashover probability is calculated on the basis of engineering method, which evaluates breakdown strength of insulation for nonstandard waveshapes, and probability data on lightning currents. Different approaches are examined for identifying the back flashover probability, as not only amplitudes but also other parameters can be taken into account. Finite-difference time-domain method is used for calculations of transients. It is found that lightning current waveform can greatly influence calculated back flashover probability value.

关键词： grounding     transmission line tower     back flashover probability     FDTD method    

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标题 作者 时间 类型 操作

Improvement of part-load performance of gas turbine by adjusting compressor inlet air temperature and IGV opening

期刊论文

Stability and agility: biped running over varied and unknown terrain

Yang YI,Zhi-yun LIN

期刊论文

Analysis on running safety of train on the bridge considering sudden change of wind load caused by wind

Tian ZHANG, He XIA, Weiwei GUO

期刊论文

Thermodynamic analysis of reaction pathways and equilibrium yields for catalytic pyrolysis of naphtha

期刊论文

破纪录的黑科技跑鞋

Chris Palmer

期刊论文

余弦忆导忆阻系统周期变化初值位移调控行为

Mo CHEN, Xue REN, Hua-gan WU, Quan XU, Bo-cheng BAO

期刊论文

Dynamic response of a long span suspension bridge and running safety of a train under wind action

GUO Weiwei, XIA He, XU You-lin

期刊论文

Measurement and correlation of the solid-liquid equilibrium of 2-(

Yanhong SUN, Zhiyong LI, Chuang XIE, Wei CHEN, Cui ZHANG

期刊论文

Acoustic fault signal extraction via the line-defect phononic crystals

期刊论文

Brown marine algae turbinaria conoides as biosorbent for Malachite green removal: Equilibrium and kinetic

R. RAJESH KANNAN, M. RAJASIMMAN, N. RAJAMOHAN, B. SIVAPRAKASH,

期刊论文

Calculations of narrow-band transimissities and the Planck mean absorption coefficients of real gases using line-by-line

Huaqiang CHU, Mingyan GU, Huaichun ZHOU, Fengshan LIU

期刊论文

Non-equilibrium model for catalytic distillation process

WANG Feng, ZHAO Ning, LI Junping, XIAO Fukui, WEI Wei, SUN Yuhan

期刊论文

Pareto lexicographic α-robust approach and its application in robust multi objective assembly line balancing

null

期刊论文

Machine learning for detecting mesial temporal lobe epilepsy by structural and functional neuroimaging

Baiwan Zhou, Dongmei An, Fenglai Xiao, Running Niu, Wenbin Li, Wei Li, Xin Tong, Graham J Kemp, Dong

期刊论文

Choosing configurations of transmission line tower grounding by back flashover probability value

Dmitry KUKLIN

期刊论文