Measurement of the thermal transport properties of dielectric thin films using the micro-Raman method

The micro-Raman method is a non-contact and non-destructive method for thermal conductivity measurement. To reduce the measurement error induced by the poor fit of the basic equation of the original micro-Raman method, we developed a new basic equation for the heat source ofa Gaussian laser beam. Based on the new basic equation, an analytical heat transfer model has been built to extend the original micro-Raman method to thin films with submicrometer- or nanometer-scale thickness. Experiments were performed to measure the thermal conductivity of dielectric thin films with submicrometer- or nanometer-scale thickness. The thermal resistance of the interface between dielectric thin films and their silicon substrate was also obtained. The obtained thermal conductivity of silicon dioxide film is 1.23 W/（m.K）, and the interface thermal resistance between silicon dioxide film and substrate is 2.35×10^-8 m^2.K/W. The thermal conductivity and interface thermal resistance of silicon nitride film are 1.07 W/（m.K） and 3.69×10^-8 m^2.K/W, respectively. The experimental results are consistent with reported data.     

Surface morphologies of aluminum films on silicone oil surfaces

The surface morphology and growth mechanism of an aluminum film system deposited on silicone oil surfaces by a vapor depositing method was investigated by scanning electron microscopy. It was found that the perpendicular fluctuation of the film's bottom surface was more remarkable than that of the film's top surface. Near the joint between the film on the silicone oil substrate and the film on the silicon wafer surface on which the silicone oil substrate rested, was a naturally formed anomalous wedge-shaped wrinkly structure with slopes of 10⁻⁴–10⁻⁵ rad, whose growth mechanism could be interpreted under the assumption of the thermal expansion behavior of the liquid substrates. Project supported by NSFC (No. 19874016) and the Special Fund of Zhejiang Provincial Natural Science Foundation for Young Scientists (Grant No. 1997RC9603).     

Control system for dynamic testing platform of asymmetrical pitch mechanism

A novel asymmetrical pitch system for rotary wing is presented. The pitch control characteristics are studied and analyzed. Because elastic linkage is a key part in whole asymmetrical pitch system, in order to obtain the variation of the elastic linkage deformation, an experimental platform mainly based on the device of micro aerial vehicles (MAVs) and a new control system mounted on TMS320LF2407 are designed. This control system has its compacted configuration and reliability. Finally, using this system to control the MAV for simulating the flying forward, experimental results show the MAV’s flight attitude can be controlled based on the variation of the elastic linkage. Project supported by the National Natural Science Foundation of China (Grant No.60605028), the National High-Technology Research and Development Program of China (Grant No.2007AA04Z225), the Shanghai Rising-Star Program (Grant Nos.07QA14024, 07QH14006), the Shanghai Shuguang Program (Grant No.07SG47), and the Shanghai Leading Key Laboratory of Mechanical Automation and Robotics Science Foundation (Grant No.ZZ0805)     

CdS/SiO2 nanowire arrays and CdS nanobelt synthesized by thermal evaporation

INTRODUCTION The richness of fundamental phenomena and the potential applications in nano-technologies has ar- oused rapidly growing interest in nano-dimensional materials. Quasi-one-dimensional (1D) nano-semi- conductors in the form of nanowires and nanoribbons have recently been successfully fabricated in many laboratories and by many methods (Wu et al., 2004; Yang et al., 2005; Gan et al., 2004; Soumitra et al., 2006). To synthesize CdS nanowires, people have developed a series of sy…     

Control of orbit and control of chaos in a class of dynamic system

１　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｃｏｎｓｉｄｅｒｔｈｅｍｏｄｅｌｘ　¨＋ｘ（１－ｘ）（ｘ－ａ）＝０,（１）ｗｈｅｒｅａｉｓａｃｏｎｓｔａｎｔ．Ａｓａ＝－１,Ｅｑ．（１）ｒｅｄｕｃｅｓｔｏｔｈｅＤｕｆｆｉｎｇｅｑｕａｔｉｏｎｆｏｒｔｈｅｓｙｓｔｅｍｏｆｓｏｆｔｓｐｒｉｎｇｗｉｔｈｏｕｔｄａｍｐｉｎｇｘ　¨＋ｘ－ｘ３＝０．（２）　ＴｈｅＤｕｆｆｉｎｇｓｙｓｔｅｍｈａｓｂｒｏａｄｅｎｇｉｎｅｅｒｉｎｇｂａｃｋｇｒｏｕｎｄ．Ｔｈｅｒｅａｒｅｐａｐｅｒｓ［１～４］ｒｅｌａｔｅｄｔｏｔｈｅｄｙｎａｍｉｃ…     

Stabilization for a class of second-order switched systems with saturation constrains

This paper proposes a global stabilization method for a class of planar switched systems with input saturation constrains by using a state feedback and switching strategy. This method is proved to be effective by analyzing the characteristics of the trajectory of second-order linear systems with input saturation. Project supported by the China Postdoctoral Science Foundation (Grant No.20070420643), the National Natural Science Foundation of China (Grant No.60774059), and the Innovation Program of the Shanghai Municipal Science and Technology Commission (Grant No.08DZ2272400)     

Multiresolution image fusion scheme based on fuzzy region feature

INTRODUCTION Image fusion can be defined as the process by which several images, or some of their features, are combined together to form different modalities or instruments, and is of great importance in many ap- plications (Hall and Llinas, 1997; Zhou et al., 1998), such as object detection, ATR (Automatic Target Recognition), remote sensing, computer vision, and robotics. Recently some researchers recognized that it seems more meaningful to combine objects/regions rather than pixels…     

Experimental study of active magnetic bearing on a 150M3 turbo oxygen gas expander

This paper is concerned with the investigation, experiment and design analyses on the application of active magnetic bearings for a 150M³ turbo oxygen gas expander having 1.16 kg weight and 30 mm diameter rotor, which was supported by two aerostatic bearings formerly. Now, the machine can work steady at a rotation speed of 92,000 r/min, and can be run up to a maximum rotation speed of 104,000 r/min. Project supported by the Science and Technology Development Foundation of Educational and Science Commission of Shanghai (59875054)     

Hilbert‘s Sixteenth Problem and Its Generalization

This paper deals with Hilbert‘s 16th problem and its generalizations.The configurations of all closed branches of an algebraic curve of degreee n are discussed.The maximum number of sheets for an algebraic equation of degree n and the maximum number of limit cycles for a planar algebraic autonomous system are achieved.The author also considers different generalizations and some related problems.     

Run-to-run product quality control of batch processes

Batch processes have been increasingly used in the production of low volume and high value added products. Consequently, optimization control in batch processes is crucial in order to derive the maximum benefit. In this paper, a run-to-run product quality control based on iterative learning optimization control is developed. Moreover, a rigorous theorem is proposed and proven in this paper, which states that the tracking error under the optimal iterative learning control (ILC) law can converge to zero. In this paper, a typical nonlinear batch continuous stirred tank reactor (CSTR) is considered, and the results show that the performance of trajectory tracking is gradually improved by the ILC. Project supported by the Science Foundation of Shanghai Municipal Education Commission (Grant No.09Y208), and the Science Foundation of Science and Technology Commission of Shanghai Municipality (Grant Nos.08DZ2272400, 09DZ2273400) and the “11th Five-Year Plan” 211 Construction Project of Shanghai University     

Combinatorial model involving mixed deterministic freight volume distribution and user’s equilibrium assignment

Considering characteristics of Chinese urban mixed traffic, the author develops a combinatorial model involving the mixed deterministic traffic volume distribution and user’s equilibrium (UE) assignment on the basis of symmetrical link travel time function (or deterrence). Its uniqueness and equivalance to the Wardropian principle of UE are also proved. Finally, we give the algorithm of model. Project supported by the Youth Scientific Foundation of Shanghai Municipal Commission of Education (97QG18)     

Novel electro-optical modulator utilizing GeO2-doped silica waveguide

In order to achieve a modulator with broad bandwidth and perfect impedance match, a novel electro-optical modulator based on GeO₂-doped silica waveguides on silicon substrate is designed. The finite element model of the whole electro-optical modulator is established by means of ANSYS. With the finite element method analysis, the performance of the novel modulator is predicted. The simulation reveals that the designed modulator operates with a product of 3 dB optical bandwidth and modulating length of 226.59 GHz·cm, and a characteristic impedance of 51.6 Ω at 1 550 nm wavelength. Moreover, the calculated electrical reflected power of coplanar waveguide electrode is below −20 dB in the frequency ranging from 45 MHz to 65 GHz. Therefore, the designed modulator has wide modulation bandwidth and perfect impedance match. Supported by National Natural Science Foundation of China (No.60577023)and Key Laboratory of Opto-Electronics Information and Technical Science of Ministry of Education, China. LI Jiusheng, born in 1976, male, Dr.     

On the characteristics of rheological fracture of rock

Based on the traditional theory of fracture, time-dependence of rock fracture is taken into account and the creep fracture criteria are given. The effect of the microcrack zone on fracture toughness is analyzed. Finally, a model for time prediction of rheological fracture is derived and its feasibility is proven. Supported by the National Natural Science Foundation of China (59809005) and the Science Foundation of Shanghai Municipal Commission of Science and Technology (96QF14009)     

乙烯基聚合物和(口恶)二唑衍生物的电致发光器件中激基复合物的蓝色发射

Two types of molecular and polymer devices employing (2-(4′-biphenyl)-5-(4““““““““-tert-butylphenyl)-1,3,4-oxadiazole) (PBD)and poly(N-vinylcarbazole) (PVK) as electron transport and hole transport materials, respectively, have been fabricated. The structures of these two devices are ITO/PVK( 70 nm)/PBD(60 nm)/A1 and ITO/PVK: PBD (1:1 by mass, 70 nm)/A1. The formation of exciplex is evident by comparing the electroluminescence (EL) of a bi-layer device and the photoluminescence (PL) of a PVK and PBD mixed film.The maximum emission energy of exciplex evaluated is consistent with the peak emission of EL. Blue emissions from both devices are obtained. The type of exicplex is interpreted based on the energy level diagram of the bi-layer device.     

A new stochastic algorithm of global optimization—Region’s walk and contraction

This paper presents a new stochastic algorithm for box-constrained global optimization problem. Bacause the level set of objective function is always not known, the authors designed a region containing the current minimum point to replace it, and in order to fit the level set well, this region would be walking and contracting in the running process. Thus, the new algorithm is named as region’s walk and con-traction(RWC). Some numerical experiments for the RWC were conducted, which indicate good property of the algorithm. Supported by the Science Foundation of Shanghai Municipal Commission of Education     

Reconstruction from contour lines based on bi-cubic Bezier spline surface

A novel reconstruction method from contours lines is provided. First, we use a simple method to get rid of redundant points on every contour, then we interpolate them by using cubic Bézier spline curve. For corresponding points of different contours, we interpolate them by the cubic Bézier spline curve too, so the whole surface can be reconstructed by the bi-cubic Bézier spline surface. The reconstructed surface is smooth because every Bézier surface is patched with G² continuity, the reconstruction speed is fast because we can use the forward elimination and backward substitution method to solve the system of tridiagonal equations. We give some reconstruction examples at the end of this paper. Experiments showed that our method is applicable and effective. Project supported by the National Natural Science Foundation of China (Nos. 60373070 and 60573147), Postdoctor Foundation of Shanghai (No. 05R214129), and Zhejiang Education Foundation of China (No. 20050786)     

固定化细胞滤床和生物膜滤床净化二甲苯的比较

The Bacillus firmus was immobilized into Ca-alginate beads according to the different initial biomass concentration, calcification time and activation time.Three types of immobilized Bacillus firmus beads were packed respectively in trickling biofilter to purify xylene contained waste gases,and the performance of immobilized-cell biofilter was compared with traditional biofilm attached biofilter packed with two types of ceramic pellets.The results showed that three types of immobilized beads had different capabilities for removing xylene and life-spans.Higher initial biomass in immobilized beads resulted in better performance but shorter life-span.Activation process can remarkably enhance the activity of bacteria,and the removal efficiency of xylene can substantially be improved.Calcification time had influence on life-span of immobilized beads.Without acclimation,the cell-entrapped biofilter can obtain the maximum elimination capacity of 92.4 g/(m~3·h).However,compared with biofilm attached biofilter,it has a poorer intrinsic drawback in volatile organic compounds (VOCs) removal due to the existence of excess mass transfer resistance.     

Fluorescence Properties of Eu^3＋：Y2SiO5 Single Crystal

Fluorescence properties of Eu^3 :Y2SiO5 have been investigated.Transitions between ^5D and ^7Fwere were studied with transmission spectra,fluorescence spectra,photoluminescence excitation(or absorption) spectra and site selective fluorescence spectra.The X-ray powder diffraction pattern of Eu^3 :Y2SiO5 shows that the crystal belong to monoclinic,and lattice‘s constants a,b,c and β arc obtaned by a simulation with the measured diffraction angles.     

A Note on Global Convergence Result for Conjugate Gradient Methods

We extend a results presented by Y.F.Hu and C.Storey(1991)^[1] on the global convergence rsult for conjugate gradient methods with different choices for the parameter βk.In this note,the conditions given on βk are milder than that used by Y.F.Huang C.Storey.     

Experimental Study on Mechanical Properties of Micro-Structured Porous Silicon Film

Mechanical properties of micro-structured porous silicon film (PS) were studied combining X-ray diffraction with micro-Raman spectroscopy. The micro-structured porous silicon samples with different porosities ranging from 30.77% to 96.25% were obtained by chemical etching. Lattice parameters of the samples were measured using X-ray diffraction and its maximal change is up to 1.0%. This lattice mismatch with the bulk silicon substrate may introduce residual stress to the porous film. The residual stress measurement by micro-Raman spectroscopy reveals that the maximum of tensile residual stress has reached GPa level in the porous film. Moreover, the lattice mismatch and its corresponding residual stress are increasing with the porosity of PS, but average elastic modulus is about 14.5 GPa, one order of magnitude lower than that of substrate Si. The mechanical properties of PS have aclose relation with its micro-pore structure.