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The optical near-field speckles and their first order statistics on the basis of the integral equations of electromagnetic field

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Science China(Physics,Mechanics & Astronomy) 2004年第3期47卷 365-380页

作者： CHENG Chuanfu1, 2. SONG Hongsheng2. LIU Chunxiang2. ren Xiaorong2. ZHANG ningyu{2. TENG Shuyun1 & XU Zhizhan1 1. Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P. O. Box 800-2.1, Shanghai 2.1800, China 2. {{2. of Physics, Shandong Normal university, Jinan 2.0014, China {2. Shandong Institute of Architecture and Engineering, Jinan 2.0014, China 1. Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences P. O. Box 800-211 201800 Shanghai China 2. department of Physics Shandong Normal University 250014 Jinan China 3. Shandong Institute of Architecture and Engineering 250014 Jinan China

From Helmholtz equation of the harmonic electromagnetic waves, the integral equations of the light field at the medium boundaries are obtained by use of the Green's theorem and are discretized into linear equation set with the values of the light field and its derivative as the unknowns. On solving the linear equation set, we realize the rigorous computations of the light fields at the boundaries. Then the intensities of the light waves scattered by the random self-affine fractal surfaces in the optical near-field are calculated, and the propagation characteristics, the evolutions of the contrast and the intensity probability density function of the near-field speckles are studied in detail. The near-field speckles are much different from the conventional speckles in the diffraction regions and in the imaging systems. There are obvious local fluctuations in the intensity distributions of the near-field speckles and such fluctuations disappear after propagating a distance of one wavelength from the medium surfaces. For the random surfaces with smaller lateral correlation lengths, the speckle contrasts approach the saturation values and the speckle fields approach Gaussian distribution within the near-field, while for the random surfaces with larger lateral correlation lengths, such evolutions become comparatively slow.

关键词： speckle, near-field optics, first order statistics, Green's function.

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Effects of Co-Firing Biomass and Pulverized Coal on NO Reduction in Cement Precalciner

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Journal of Thermal Science 2024年第2期33卷 751-760页

作者： LI Pengpeng ren Qiangqiang LYU Qinggang WANG Mingyue School of Energy Power and Mechanical Engineering North China Electric Power UniversityBeijing102206China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing100190China university of Chinese Academy of Sciences Beijing100049China

With increased awareness of the large-scale CO_(2. emissions from the cement industry,there has been growing focus on greenhouse gas reduction *** all these strategies,fuel substitution using biomass fuel is extensively used to achieve CO_(2. zero-emission in cement *** to the avoidable high-temperature-generated thermal nitrogen oxides during cement production,research on the impact of biomass application on nitrogen oxide emissions shall be carried *** types of biomass fuel and bituminous coal were used to investigate the NO reduction characteristics under different O_(2. concentrations on experimental *** was found that the change in oxygen concentration from 9% to 1% increased the reaction time in the reactor from 555 s to 142. s,which means the increase in oxygen concentration can lead to shorter reaction time,and correspondingly,the existing time of nitric oxide in the flue gas is also shortened,but the peak value of nitric oxide rises,during the process of O_(2. concentration changing from 1% to 9%,the peak NO concentration in the flue gas increased from 5.4×10^(-5) to 1.05×10^(-4).An increase in O_(2. concentration greatly reduces the total reduction of NO and the minimum change in NO *** peak NO concentration during the combustion process of corn stalk is 4.56×10^(-4),which is approximately 7 times higher than that of coal,and it is caused by the high amount of N in corn *** addition of raw meal has an inhibitory effect on the reduction of NO:after adding raw meal,the effective reduction time of NO by fuel decreased by about 2.%,but adding raw meal raises CO_(2. concentration of fuel gas in the early stage of reaction.

关键词： cement precalciner biomass fuel coal NO reduction co-firing

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New Complex Nonlinear optical Crystal-Bis(4-methoxybenzaldehyde thiosemicarbazone) Zinc Chloride(ZnL_2.l_2.

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Chinese Chemical Letters 1998年第2期9卷 215-217页

作者： Yu Peng TIAN Jie Ying WU Fu Xin XIE and Shi Sheng ni(department of Chemistry, Anhui {2., Hefei {3.oordination Chemistry Institute, State Key Laboratory of nanjing university. nanjing {3. Anhui Univ Dept Chem Hefei 230093 Peoples R China nanjing Univ State Key Lab Inst Coordinat Chem Nanjing 210093 Peoples R China

The structure of ZnL2.l2.(L=4-methoxybenzaldehyde thiosemicarbazone) has beenobtained by x-ray diffraction. The compound crystallized in space group Cc with Z=4, in a unit cellof dimensions, a=9.08909(10), b=2.. l42.(10), c=11 .7890(l0)A,β=90.050(10)°, v=2.1}4.6(12.A3.Dc=1 .552.cm-3. H=1 .463.m-1. R=0.03.8. and Rw=0.0418. The structure contains individualZnL2.l2.distorted tetrahedral units in which L molecules are S-bonded as monodentate to the metalions; chloride ions are also coordinated. The nonlinear optical properties of the zinc complex arealso presented in this letter.

关键词： zinc complex- nonlinear optical crystal thiosemicarbazone derivative

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Fault diagnosis of HVAC system with imbalanced data using multi-scale convolution composite neural network

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Building Simulation 2024年第3期17卷 371-386页

作者： Rouhui Wu Yizhu ren Mengying Tan Lei nie School of Mechanical Engineering Hubei University of TechnologyWuhan430068China Industrial Research Institute of Xiangyang Hubei university of Technology Xiangyang441100China

Accurate fault diagnosis of heating,ventilation,and air conditioning(HVAC)systems is of significant importance for maintaining normal operation,reducing energy consumption,and minimizing maintenance ***,in practical applications,it is challenging to obtain sufficient fault data for HVAC systems,leading to imbalanced data,where the number of fault samples is much smaller than that of normal ***,most existing HVAC system fault diagnosis methods heavily rely on balanced training sets to achieve high fault diagnosis ***,to address this issue,a composite neural network fault diagnosis model is proposed,which combines SMOTETomek,multi-scale one-dimensional convolutional neural networks(M1DCNN),and support vector machine(SVM).This method first utilizes SMOTETomek to augment the minority class samples in the imbalanced dataset,achieving a balanced number of faulty and normal ***,it employs the M1DCNN model to extract feature information from the augmented ***,it replaces the original Softmax classifier with an SVM classifier for classification,thus enhancing the fault diagnosis *** the SMOTETomek-M1DCNN-SVM method,we conducted fault diagnosis validation on both the ASHRAE RP-1043.dataset and experimental dataset with an imbalance ratio of 1:*** results demonstrate the superiority of this approach,providing a novel and promising solution for intelligent building management,with accuracy and F1 scores of 98.45%and 100%for the RP-1043.dataset and experimental dataset,respectively.

关键词： fault diagnosis chiller imbalanced data SMOTETomek multi-scale neural networks

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Impact of wetting-drying cycles and acidic conditions on the soil aggregate stability of yellow‒brown soil

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Journal of Mountain Science 2024年第6期21卷 2075-2090页

作者： XIA Zhenyao ni Yuanzhen LIU Deyu WANG Di XIAO Hai Key Laboratory of Geological Hazards on Three Gorges Reservoir Area Ministry of EducationYichang 443002China College of Civil Engineering&Architecture China Three Gorges UniversityYichang 443002China Engineering Research Center of Eco-environment in Three Gorges Reservoir Region Ministry of EducationChina Three Gorges UniversityYichang 443002China

Soil aggregate is the basic structural unit of soil,which is the foundation for supporting ecosystem functions,while its composition and stability is significantly affected by the external *** study was conducted to explore the effect of external environment(wetting-drying cycles and acidic conditions)on the soil aggregate distribution and stability and identify the key soil physicochemical factors that affect the soil aggregate *** yellow‒brown soil from the Three Gorges Reservoir area(TGRA)was used,and 8 wetting-drying conditions(0,1,2.{2.4,5,10 and 15 cycles)were simulated under 4 acidic conditions(pH={2.4,5 and 7).The particle size distribution and soil aggregate stability were determined by wet sieving method,the contribution of environmental factors(acid condition,wetting-drying cycle and their combined action)to the soil aggregate stability was clarified and the key soil physicochemical factors that affect the soil aggregate stability under wetting-drying cycles and acidic conditions were determined by using the Pearson’s correlation analysis,Partial least squares path modeling(PLS‒PM)and multiple linear regression *** results indicate that wetting-drying cycles and acidic conditions have significant effects on the stability of soil aggregates,the soil aggregate stability gradually decreases with increasing number of wetting-drying cycles and it obviously decreases with the increase of ***,the combination of wetting-drying cycles and acidic conditions aggravate the reduction in the soil aggregate *** wetting-drying cycles,acidic conditions and their combined effect imposes significant impact on the soil aggregate stability,and the wetting-drying cycles exert the greatest *** soil aggregate stability is significantly correlated with the pH,Ca^(2.),Mg^(2.),maximum disintegration index(MDI)and soil bulk density(SBD).The PLS‒PM and multiple linear regression analysis further reveal that the soil aggre

关键词： Yellow‒brown soil Wetting-drying cycles Acidic conditions Soil aggregate stability Soil disintegration

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Magnetic properties of small Fe clusters: a nonorthogonal Hamiltonian study

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原子与分子物理学报 2000年第4期17卷 583-588页

作者： ren Yun 1,2.,SUN hou qian 1,2., WANG Bao lin 1, LUO You hua 1, WANG Guang hou 1(1. National Laboratory of Solid State Microstructures and department of Physics,{2., {3. 2.0093.2.Yancheng Institute of Technology, Jia 南京大学固体微结构物理国家重点实验室江苏南京 210093

We calculate the magnetic properties of small Fe N clusters( N =2.7,9,13.15) by using a parameterized Hubbard tight binding spd band model Hamiltonian, with the parameters obtained from nonorthogonal Hamiltonian parameters. the average magnetic moments, and the spin polarized charge distribution within clusters are in agreement with those obtained by first principle and tight binding calculations. The effect of the nonorthogonal basis is discussed.

关键词：铁团磁性 Hubbard模型

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Almandine megacrysts from Yingfengling Cenozoic basalt in Leizhou Peninsula and their parental magma origin

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Chinese Science Bulletin 2001年第14期46卷 1215-1219页

作者： YU Jinhai & S. Y. O’Reilly1. National Key Laboratory of Metallogenic Mechanism of Endogenetic Deposits, {2. of Earth Sciences,{3., nanjing 2.0093. China 2. National Key Center of GEMOC, {2. of Earth and Planetary Sciences, Macquarie university, North Ryde, NSW 2.09, Australia National Key Laboratory of Metallogenic Mechanism of Endogenetic Deposits Department of Earth Sciences Nanjing University Nanjing China National Key Center of GEMOC Department of Earth and Planetary Sciences Macquarie University North Ryde Australia

The garnet megacrysts from Yingfengling basalts are characterlzed by high FeO (>2.%), CaO (7.02. -8.16%) and low MgO (5.88%-10.87%). Significant composition variations are observed in these megacrysts, of which ni, V, Sc, Co, and HREE are positively correlated with their Mg# and Zr, Hf, Ga, Y, Sr, Nb, Zn and LREE-MREE are negatively correlated with Mg#. Megacryst pa{2.t magma is a highly evolved residual melt with strongl depletion in Ti, Sr, Hf, Nb and HREE. This pa{2.tal magma was generated by more than 60% of crystallization fractionation of clinopyroxene, garnet, plagioclase and ilmenite from quartz tholeiitic magma. It has not erupted to the surface, but stayed at the upper mantle and formed the megacrystic cumulate. Megacrysts and their host basalt are in disequilibrium.

关键词： almandine megacryst geochemistry LAM-ICPMS Lei-zhou Peninsula.

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MEMS Huygens Clock Based on Synchronized Micromechanical Resonators

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Engineering 2024年第5期36卷 124-131页

作者： Xueyong Wei Mingke Xu Qiqi Yang Liu Xu a Yonghong Qi Ziming ren Juan ren Ronghua Huan Zhuangde Jiang State Key Laboratory for Manufacturing System Engineering Xi’an Jiaotong UniversityXi’an 710049China School of Construction Machinery Chang’an UniversityXi’an 710064China department of Mechanics Zhejiang UniversityHangzhou 310027China

With the continuous miniaturization of electronic devices,microelectromechanical system(MEMS)oscillators that can be combined with integrated circuits have attracted increasing *** study reports a MEMS Huygens clock based on the synchronization principle,comprising two synchronized MEMS oscillators and a frequency compensation *** MEMS Huygens clock improved shorttime stability,improving the Allan deviation by a factor of 3.73.from 19.3.to 5.17 ppb at 1 s.A frequency compensation system based on the MEMS oscillator’s temperature-frequency characteristics was developed to compensate for the frequency shift of the MEMS Huygens clock by controlling the resonator *** effectively improved the long-term stability of the oscillator,with the Allan deviation improving by 1.63.3.105 times to 3..9 ppt at 6000 *** power consumption for compensating both oscillators simultaneously is only 2.85 mW·℃^(-1).Our comprehensive solution scheme provides a novel and precise engineering solution for achieving high-precision MEMS oscillators and extends synchronization applications in MEMS.

关键词： Frequency stability Huygens clock MEMS Oscillator Synchronization

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Theoretical Modeling and Surface Roughness Prediction of Microtextured Surfaces in Ultrasonic Vibration-Assisted Milling

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 163-183页

作者： Chenbing ni Junjie Zhu Youqiang Wang Dejian Liu Xuezhao Wang Lida Zhu School of Mechanical and Automotive Engineering Qingdao University of TechnologyQingdao 266525China School of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819China

Textured surfaces with certain micro/nano structures have been proven to possess some advanced functions,such as reducing friction,improving wear and increasing *** prediction of micro/nano surface textures is of great significance for the design,fabrication and application of functional textured *** this paper,based on the kinematic analysis of cutter teeth,the discretization of ultrasonic machining process,transformation method of coordinate systems and the cubic spline data interpolation,an integrated theoretical model was established to characterize the distribution and geometric features of micro textures on the surfaces machined by diffe{3.t types of ultrasonic vibration-assisted milling(UVAM).Based on the theoretical model,the effect of key process parameters(vibration directions,vibration dimensions,cutting parameters and vibration parameters)on tool trajectories and microtextured surface morphology in UVAM is ***,the effect of phase diffe{3.ce on the elliptical shape in 2./3. ultrasonic elliptical vibration-assisted milling(UEVAM)was *** to conventional numerical models,the method of the cubic spline data interpolation is applied to the simulation of microtextured surface morphology in UVAM,which is more suitable for characterizing the morphological features of microtextured surfaces than traditional methods due to the presence of numerous micro *** prediction of surface roughness indicates that the magnitude of ultrasonic amplitude in z-direction should be strictly limited in 1D rotary UVAM,2. and 3. UEVAM due to the unfavorable effect of axial ultrasonic vibration on the surface *** study can provide theoretical guidance for the design and fabrication of microtextured surfaces in UVAM.

关键词： Theoretical modeling Microtextured surface Ultrasonic vibration-assisted milling Cubic spline interpolation Surface roughness

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Mechanism of K/ni Etching for Biochar-H_(2.O Gasification

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Journal of Harbin Institute of Technology(New Series) 2024年第3期31卷 1-18页

作者： Zhenyu Cheng dongdong Feng Qi Shang Yijun Zhao Wenda Zhang Shaozeng Sun School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China

Biomass-H_(2.O gasification is a complex thermochemical reaction,including three processes of volatile removal:homogeneous/heterogeneous reforming,biochar gasification and *** rate-determining step is biochar-H_(2.O gasification and etching so the DFT is carried out to see the catalytic role of different metal elements(K/ni)in the zigzag biochar *** calculation results show that the gasification of biochar-H_(2.O needs to go through four processes:dissociative adsorption of water,hydrogen transfer(hydrogen desorption,hydrogen atom transfer),carbon dissolution and CO *** energy barrier indicated that the most significant step in reducing the activation energy of K is reflected in the hydrogen transfer step,which is reduced from 3.4.14 kJ/mol to 152.41 kJ/mol;the catalytic effect of ni is mainly reflected in the carbon dissolution step,which is reduced from 12..3. kJ/mol to 84.8 kJ/*** existence of K causes the edge to have a stronger attraction to H and does not destroy theπbonds of biochar *** destruction ofπbonds is mainly due to the role of H free radicals,while the destruction ofπbonds will lead to easier C-C bond *** shows a strong attraction to O in OH,which forms strong ni-O chemical *** can also destroy the aromatic structure directly,making the gasification easier to *** study explored the catalytic mechanism of K/ni on the biochar-H_(2.O gasification at the molecular level and looked forward to the potential synergy of K/ni,laying a foundation for experimental research and catalyst design.

关键词： Biochar Potassium-nickel catalysis H_(2.O gasification etching Quantum chemistry Transition state theory

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