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动力学 2

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CP）；符号间干扰（inter symbol interference， ISI）；载波间干扰（inter carrier interference 1

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Calculation of collision frequency function for aerosol particles in free molecule regime in presence

Xiaowei LUO, Yannick BENICHOU, Suyuan YU

《能源前沿（英文）》 2013年第7卷第4期页码 506-510 doi: 10.1007/s11708-013-0275-5

摘要： The collision frequency function for aerosol particles has already been calculated for the free molecule regime and for the continuum range. The present work, taking into account the influence of internal force fields such as magnetic force, electric force and molecular forces, created by particles themselves, recalculated the collision frequency in the case of particles much smaller than the mean free path of the gas (free molecule regime). Attractive forces increase naturally the collision frequency, while repulsive forces decrease it. The calculation was performed for all types of central forces deriving from a potential, including Coulomb forces and Van der Waals forces.

关键词： aerosol particles collision frequency function coagulation

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Parameter identification of interconnected power system frequency after trip-out of high voltage transmission

Xuzhan ZHOU,Shanshan LIU,Mingkun WANG,Yiping DAI,Yaohua TANG

《能源前沿（英文）》 2014年第8卷第3期页码 386-393 doi: 10.1007/s11708-014-0323-9

摘要： Accurate modeling and parameters of high voltage (HV) grid are critical for stability research of system frequency. In this paper, simulation modeling of the system frequency was conducted of an interconnected power system with HV transmission lines in China. Based on recorded tripping data of the HV transmission lines, system parameters were identified by using genetic algorithm (GA). The favorable agreement between simulation results and recorded data verifies the validity of gird models and the accuracy of system parameters. The results of this paper can provide reference for the stability research of HV power grid.

关键词： high voltage (HV) grid frequency stability parameter identification primary frequency regulation (PFR)

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Dependence of error sensitivity of frequency on bias voltage in force-balanced micro accelerometer

Lili CHEN, Wu ZHOU

《机械工程前沿（英文）》 2013年第8卷第2期页码 146-149 doi: 10.1007/s11465-013-0260-z

摘要：

To predict more precisely the frequency of force-balanced micro accelerometer with different bias voltages, the effects of bias voltages on error sensitivity of frequency is studied. The resonance frequency of accelerometer under closed loop control is derived according to its operation principle, and its error sensitivity is derived and analyzed under over etching structure according to the characteristics of Deep Reaction Ion Etching (DRIE). Based on the theoretical results, micro accelerometer is fabricated and tested to study the influences of AC bias voltage and DC bias voltage on sensitivity, respectively. Experimental results indicate that the relative errors between test data and theory data are less than 7%, and the fluctuating value of error sensitivity under the range of voltage adjustment is less than 0.01 μm . It is concluded that the error sensitivity with designed parameters of structure, circuit and process error can be used to predict the frequency of accelerometer with no need to consider the influence of bias voltage.

关键词： Micro-Electro-Mechanical Systems (MEMS) micro accelerometer force-balanced micro accelerometer frequency error sensitivity

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Remote calibration system for frequency based on in-place benchmark

Xiaobin HONG, Guixiong LIU, Zhuokui WU, Xipeng DU,

《机械工程前沿（英文）》 2010年第5卷第3期页码 316-321 doi: 10.1007/s11465-010-0021-1

摘要： According to the deficiencies of remote calibration mode based on material object reference, a new model of a remote calibration system for frequency based on in-place benchmark is introduced, which is made of a calibration subsystem on the spot and a remote management subsystem. The key technology of some key problems for the remote calibration system is particularly discussed, including the time and frequency benchmark receiving module based on global positioning system (GPS), frequency comparison based on a phase method, frequency division based on dual high-frequency phase locked loop (PLL), and remote calibration based on the web. The results show that the system possesses some characteristics, such as high precision, good versatility, and no limitation of time and place.

关键词： remote calibration in-place benchmark frequency comparison global position system (GPS)

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Prediction of characteristic blast-induced vibration frequency during underground excavation by using

《结构与土木工程前沿（英文）》页码 1029-1039 doi: 10.1007/s11709-022-0861-x

摘要： Blast-induced vibration produces a very complex signal, and it is very important to work out environmental problems induced by blasting. In this study, blasting vibration signals were measured during underground excavation in carbonaceous shale by using vibration pickup CB-30 and FFT analyzer AD-3523. Then, wavelet analysis on the measured results was carried out to identify frequency bands reflecting changes of blasting vibration parameters such as vibration velocity and energy in different frequency bands. Frequency characteristics are then discussed in view of blast source distance and charge weight per delay. From analysis of results, it can be found that peak velocity and energy of blasting vibration in frequency band of 62.5–125 Hz were larger than ones in other bands, indicating the similarity to characteristics in the distribution band (31–130 Hz) of main vibration frequency. Most frequency bands were affected by blasting source distance, and the frequency band of 0–62.5 Hz reflected the change of charge weight per delay. By presenting a simplified method to predict main vibration frequency, this research may provide significant reference for future blasting engineering.

关键词： wavelet analysis blast-induced vibration frequency characteristics underground excavation

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Fuel variability effect on flickering frequency of diffusion flames

Jizhao LI, Yang ZHANG

《能源前沿（英文）》 2009年第3卷第2期页码 134-140 doi: 10.1007/s11708-009-0034-9

摘要： It is known that fuel variability of different gas suppliers may cause combustion instability in a gas turbine combustor. Mechanisms that control the time scale of the heat release oscillations and acoustic pressure perturbations are both physical and chemical in nature, and thus can be influenced by changes in fuel composition. The intent of this study is to investigate the fuel variability on the flickering frequency of diffusion flames in the hope of understanding some of the fundamental aspects of fuel variability effect on the dynamics of combustion. Experiments were conducted at atmospheric pressure with a matrix of methane and propane blends. An optical fibre system was applied to capture simultaneously the flame flickering at two different light frequencies (430 nm and 516 nm), which provided a means of comparing the chemistry change. It was found that the low frequency oscillation of flow and flame structures depended only weakly on the exit velocities of the fuel, while ambient conditions had a significant effect on flickering frequencies and spectrum. The results of using CH and C H as test fuels at different flow rates showed very little variations, with peak frequencies at 11-13 Hz. When the jet flame was not disturbed, harmonics to at least the third mode were obtained in most of these cases. However, the cases which included CH /C H splits of 90/10, 85/15 and 80/20 by volume showed that unstable flickering frequencies and flame harmonics were not observed. When a mixture of methane/propane at a ratio of 1:1 was used the peak flickering frequency was around 6 Hz, and slight disturbance in the environment would cause the harmonics to disappear. Mechanisms thought to produce changes in the dynamic response and frequency harmonics were discussed.

关键词： fuel variability flickering frequency diffusion flames dynamics of combustion

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Capacity limitation of nuclear units in grid based on analysis of frequency regulation

Yiping DAI, Pan JIANG, Lin GAO, Weimin KAN, Xiaoqing XIAO, Ge JIN

《能源前沿（英文）》 2012年第6卷第2期页码 148-154 doi: 10.1007/s11708-012-0174-1

摘要： The increasing capacity of nuclear units in power grid poses threat to system stability and security. Load disturbance may cause overspeed of the units and trigger the overspeed protection controller (OPC). Repeating actions of valves have a strong impact on the security of the equipment and may result in a collapse of the power system. Based on the analysis of frequency regulation, mathematic models for nuclear units in the grid are established in this paper to simulate the dynamic process when load disturbance occurs. The critical action of the OPC is proposed as the constraint of safe operation for the units. The relationship between different styles of frequency regulation and the allowable capacity of the nuclear units in the grid is discussed. This research can help to estimate the capacity limitation of nuclear units in the grid.

关键词： nuclear units capacity overspeed primary frequency control (PFC) second frequency control (SFC)

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Time-domain and frequency-domain approaches to identification of bridge flutter derivatives

Zhengqing CHEN

《结构与土木工程前沿（英文）》 2009年第3卷第2期页码 173-179 doi: 10.1007/s11709-009-0034-1

摘要： Flutter derivatives are essential for flutter analysis of long-span bridges, and they are generally identified from the vibration testing data of a sectional model suspended in a wind tunnel. Making use of the forced vibration testing data of three sectional models, namely, a thin-plate model, a nearly streamlined model, and a bluff-body model, a comparative study was made to identify the flutter derivatives of each model by using a time-domain method and a frequency-domain method. It was shown that all the flutter derivatives of the thin-plate model identified with the frequency-domain method and time-domain method, respectively, agree very well. Moreover, some of the flutter derivatives of each of the other two models identified with the two methods deviate to some extent. More precisely, the frequency-domain method usually results in smooth curves of the flutter derivatives. The formulation of time-domain method makes the identification results of flutter derivatives relatively sensitive to the signal phase lag between vibration state vector and aerodynamic forces and also prone to be disturbed by noise and nonlinearity.

关键词： long-span bridges wind-induced vibration flutter derivatives forced vibration test time-domain method frequency-domain method

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Oscillation frequency of simplified arterial tubes

Hui AN, Fan HE, Lingxia XING, Xiaoyang LI

《机械工程前沿（英文）》 2009年第4卷第3期页码 300-304 doi: 10.1007/s11465-009-0038-5

摘要： To construct the spatial kinetic equation of an arterial tube and obtain its radial natural frequency, a linear-elastic and small deformation condition is assumed. The theoretical analysis is first presented and the finite element method is then used to numerically simulate the spatial kinematics. The results show that the first-order frequency is 15.8 Hz and the obtained exact analytical solutions agree well with numerical solutions, which proves that the theoretical analysis and numerical simulation are both correct.

关键词： spatial kinematics natural frequency finite element method

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Optimal generation scheduling in power system using frequency prediction through ANN under ABT environment

Simarjit KAUR, Yajvender Pal VERMA, Sunil AGRAWAL

《能源前沿（英文）》 2013年第7卷第4期页码 468-478 doi: 10.1007/s11708-013-0282-6

摘要： In a competitive and deregulated power scenario, the utilities try to maintain their real electric power generation in balance with the load demand, which creates a need for the precise real time generation scheduling (GS). In this paper, the GS problem is solved to perform the unit commitment (UC) based on frequency prediction by using artificial neural network (ANN) with the objective to minimize the overall system cost of the state utility. The introduction of availability-based tariff (ABT) signifies the importance of frequency in GS. Under-prediction or over-prediction will result in an unnecessary commitment of generating units or buying power from central generating units at a higher cost. Therefore, an accurate frequency prediction is the first step toward optimal GS. The dependency of frequency on various parameters such as actual generation, load demand, wind power and power deficit has been considered in this paper. The proposed technique provides a reliable solution for the input parameter different from the one presented in the training data. The performance of the frequency predictor model has been evaluated based on the absolute percentage error (APE) and the mean absolute percentage error (MAPE). The proposed predicted frequency sensitive GS model is applied to the system of Indian state of Tamilnadu, which reduces the overall system cost of the state utility by keeping off the dearer units selected based on the predicted frequency.

关键词： artificial neural network (ANN) frequency prediction availability-based tariff (ABT) generation scheduling (GS)

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Frequency domain a9ctive vibration control of a flexible plate based on neural networks

Jinxin LIU, Xuefeng CHEN, Zhengjia HE

《机械工程前沿（英文）》 2013年第8卷第2期页码 109-117 doi: 10.1007/s11465-013-0252-z

摘要：

A neural-network (NN)-based active control system was proposed to reduce the low frequency noise radiation of the simply supported flexible plate. Feedback control system was built, in which neural network controller (NNC) and neural network identifier (NNI) were applied. Multi-frequency control in frequency domain was achieved by simulation through the NN-based control systems. A pre-testing experiment of the control system on a real simply supported plate was conducted. The NN-based control algorithm was shown to perform effectively. These works lay a solid foundation for the active vibration control of mechanical structures.

关键词： active vibration control (AVC) neural network (NN) low frequency noise frequency domain control multi-frequency control

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Research progress in pathogenic genes of hereditary non-syndromic mid-frequency deafness

null

《医学前沿（英文）》 2016年第10卷第2期页码 137-142 doi: 10.1007/s11684-016-0449-8

摘要：

Hearing impairment is considered as the most prevalent impairment worldwide. Almost 600 million people in the world suffer from mild or moderate hearing impairment, an estimated 10% of the human population. Genetic factors play an important role in the pathogenesis of this disorder. Hereditary hearing loss is divided into syndromic hearing loss (associated with other anomalies) and non-syndromic hearing loss (not associated with other anomalies). Approximately 80% of genetic deafness is non-syndromic. On the basis of the frequency of hearing loss, hereditary non-syndromic hearing loss can be divided into high-, mid-, low-, and total-frequency hearing loss. An audiometric finding of mid-frequency sensorineural hearing loss, or a “bowl-shaped” audiogram, is uncommon. Up to now, merely 7 loci have been linked to mid-frequency hearing loss. Only four genetic mid-frequency deafness genes, namely, DFNA10 (EYA4), DFNA8/12 (TECTA), DFNA13 (COL11A2), DFNA44 (CCDC50), have been reported to date. This review summarizes the research progress of the four genes to draw attention to mid-frequency deafness genes.

关键词： hereditary non-syndromic hearing loss mid-frequency hearing loss deafness genes

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Analysis of frequency characteristics of compliant mechanisms

WANG Wenjing, YU Yueqing

《机械工程前沿（英文）》 2007年第2卷第3期页码 267-271 doi: 10.1007/s11465-007-0046-2

摘要： Much work is needed for a further study on the dynamic analysis of compliant mechanisms to improve their performance and operational accuracy. This paper uses the finite element method to develop a dynamic equation of the compliant mechanism. Natural frequencies and modes are derived. Using the differentials of a stiffness matrix to design parameters, a method for calculating the sensitivity of natural frequency is presented. The numerical simulation results indicate that the design parameters have an impact on the frequency characteristics of the compliant mechanisms and the proposed method is more accurate and convenient for analyzing frequency characteristics.

关键词： compliant mechanisms convenient sensitivity work analysis

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Optimization of urban bus operation frequency under common route condition with rail transit

Bin YU, Sijia REN, Enze WU, Yifan ZHOU, Yunpeng WANG

《工程管理前沿（英文）》 2017年第4卷第4期页码 451-462 doi: 10.15302/J-FEM-2017036

摘要： The overlap of bus and rail transit routes is common in China. This overlap provides passengers multiple choices for one trip. However, the availability of multiple options would cause uncertainty in the travel distribution of passengers. Given that buses and rail transits are becoming increasingly common, this paper aims to present the overlapped operation condition of bus and rail transit using a bi-level model from the perspective of bus operators. Frequency optimization model is established in the upper-level model. A heuristic algorithm called shuffled complex evolution (SCE-UA) method is used to solve the established frequency optimization model, and three other heuristic methods are compared with SCE-UA. A lower-level Logit model based on Agent simulation is set for traffic mode split. Data on the transit system in Dalian city are chosen as an example to test the feasibility of the model and the algorithm. Results show that as the overlapped optimization of bus route and rail transit routes changed primary bus frequency, the use of SCE-UA to solve such problems has evident advantages and feasibility; furthermore, changed bus frequency would improve bus operations.

关键词： common route bus operation frequency bi-level model Agent simulation SCE-UA algorithm

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Ambient photolysis frequency of NO

Qi Zou,Keding Lu,Yusheng Wu,Yudong Yang,Zhuofei Du,Min Hu

《环境科学与工程前沿（英文）》 2016年第10卷第6期 doi: 10.1007/s11783-016-0885-3

摘要： • Chemical actinometer (CA) was built for NO photolysis frequency, j(NO ), analysis. • CA data (10% accuracy) were compared with spectroradiometer (SR) data. • Long-term j(NO ) measurement was validated by comparison of CA and SR. • Dis-benefit of aerosol on j(NO ) due toparticulate matter (PM ) control on O . The photolysis frequency of NO , j(NO ), is an important analytical parameter in the study of tropospheric chemistry. A chemical actinometer (CA) was built to measure the ambient j(NO ) based on a high precision NO instrument with 1 min time resolution. Parallel measurements of the ambient j(NO ) by using the CA and a commercial spectroradiometer (SR) were conducted at a typical urban site (Peking University Urban Environmental Monitoring Station) in Beijing. In general, good agreement was achieved between the CA and SR data with a high linear correlation coefficient ( = 0.977) and a regression slope of 1.12. The regression offset was negligible compared to the measured signal level. The j(NO ) data were calculated using the tropospheric ultraviolet visible radiation (TUV) model, which was constrained to observe aerosol optical properties. The calculated j(NO ) was intermediate between the results obtained with CA and SR, demonstrating the consistency of all the parameters observed at this site. The good agreement between the CA and SR data, and the consistency with the TUV model results, demonstrate the good performance of the installed SR instrument. Since a drift of the SR sensitivity is expected by the manufacturer, we propose a regular check of the data acquired via SR against those obtained by CA for long-term delivery of a high quality series of j(NO ) data. Establishing such a time series will be invaluable for analyzing the long-term atmospheric oxidation capacity trends as well as O pollution for urban Beijing.

关键词： Photolysis frequency of nitrogen dioxide Chemical actinometer Spectroradiometer Tropospheric ultraviolet visible radiation model

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标题作者时间类型操作

Calculation of collision frequency function for aerosol particles in free molecule regime in presence

Xiaowei LUO, Yannick BENICHOU, Suyuan YU

期刊论文

Parameter identification of interconnected power system frequency after trip-out of high voltage transmission

Xuzhan ZHOU,Shanshan LIU,Mingkun WANG,Yiping DAI,Yaohua TANG

期刊论文

Dependence of error sensitivity of frequency on bias voltage in force-balanced micro accelerometer

Lili CHEN, Wu ZHOU

期刊论文

Remote calibration system for frequency based on in-place benchmark

Xiaobin HONG, Guixiong LIU, Zhuokui WU, Xipeng DU,

期刊论文

Prediction of characteristic blast-induced vibration frequency during underground excavation by using

期刊论文

Fuel variability effect on flickering frequency of diffusion flames

Jizhao LI, Yang ZHANG

期刊论文

Capacity limitation of nuclear units in grid based on analysis of frequency regulation

Yiping DAI, Pan JIANG, Lin GAO, Weimin KAN, Xiaoqing XIAO, Ge JIN

期刊论文

Time-domain and frequency-domain approaches to identification of bridge flutter derivatives

Zhengqing CHEN

期刊论文

Oscillation frequency of simplified arterial tubes

Hui AN, Fan HE, Lingxia XING, Xiaoyang LI

期刊论文

Optimal generation scheduling in power system using frequency prediction through ANN under ABT environment

Simarjit KAUR, Yajvender Pal VERMA, Sunil AGRAWAL

期刊论文

Frequency domain a9ctive vibration control of a flexible plate based on neural networks

Jinxin LIU, Xuefeng CHEN, Zhengjia HE

期刊论文

Research progress in pathogenic genes of hereditary non-syndromic mid-frequency deafness

null

期刊论文

Analysis of frequency characteristics of compliant mechanisms

WANG Wenjing, YU Yueqing

期刊论文

Optimization of urban bus operation frequency under common route condition with rail transit

Bin YU, Sijia REN, Enze WU, Yifan ZHOU, Yunpeng WANG

期刊论文

Ambient photolysis frequency of NO

Qi Zou,Keding Lu,Yusheng Wu,Yudong Yang,Zhuofei Du,Min Hu

期刊论文

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