大阵列数光阵列发生器研究

研究了产生大阵列数的光阵列发生器的设计与加工 ,设计并加工了产生一维 6 4点阵和二维 40 96点阵的光阵列发生器。

小F数衍射微透镜阵列光学性能研究

本文基于小光点扫描 ,在国内首次提出了一种测试小 F数衍射微透镜阵列光学性能的方法 .利用光通信用半导体激光器和探测器建立了一套测试系统 ,并对所研制的大阵列 ,小单元尺寸的多相位菲涅耳衍射微透镜阵列的衍射效率和点扩散函数进行了测试 .结果表明 ,衍射微透镜实际衍射光斑比理论衍射受限光斑扩展不大 ,8相位和 1 6相位石英微透镜的衍射效率分别高达 80 .2 %和 87.5 % ,说明本实验室对多相位的设计理论和制作工艺已基本掌握 。

采用液晶空间光调制器的可控性阵列菲涅耳波带片

利用液晶空间光调制器的光学调制特性 ,实现阵列数与焦长可调控的阵列菲涅耳波带片 ,并给出了理论分析和实验结果 ,该方法操作简单。

Ex⁃situ Measurement of Internal Deformation in Ball Grid Array Package with Digital Volume Correlation

In spacecraft electronic devices,the deformation of solder balls within ball grid array(BGA)packages poses a significant risk of system failure.Therefore,accurately measuring the mechanical behavior of solder balls is crucial for ensuring the safety and reliability of spacecraft.Although finite element simulations have been extensively used to study solder ball deformation,there is a significant lack of experimental validation,particularly under thermal cycling conditions.This is due to the challenges in accurately measuring the internal deformations of solder balls and eliminating the rigid body displacement introduced during ex-situ thermal cycling tests.In this work,an ex-situ three-dimensional deformation measurement method using X-ray computed tomography(CT)and digital volume correlation(DVC)is proposed to overcome these obstacles.By incorporating the layer-wise reliability-guided displacement tracking(LW-RGDT)DVC with a singular value decomposition(SVD)method,this method enables accurate assessment of solder ball mechanical behavior in BGA packages without the influence of rigid body displacement.Experimental results reveal that BGA structures exhibit progressive convex deformation with increased thermal cycling,particularly in peripheral solder balls.This method provides a reliable and effective tool for assessing internal deformations in electronic packages under ex-situ conditions,which is crucial for their design optimization and lifespan predictions.

微热管阵列热回收在空调系统中的应用研究

热回收技术对于空调系统节能具有重要意义。本文以微热管阵列热回收装置为对象,研究了平板微热管阵列排数、室内外空气温差和空气流量对热回收效率的影响程度。结果表明热回收效率会随着室内外空气温差和微热管阵列排数的增加而增加,然而热回收效率增长率会逐渐将小。随着空气流量的增加,热回收效率呈现出不断减小的趋势。在实际应用中,对于该装置,选择合适的风量对于空调系统节能尤为重要。

Stochastic resonance based on correlation coefficient in parallel array of threshold devices

The phenomenon of stochastic resonance （SR） based on the correlation coefficient in a parallel array of threshold devices is discussed. For four representative noises： the Gaussian noise, the uniform noise, the Laplace noise and the Cauchy noise, when the signal is subthreshold, noise can improve the correlation coefficient and SR exists. The efficacy of SR can be significantly enhanced and the maximum of the correlation coefficient can dramatically approach to one as the number of the threshold devices in the parallel array increases. Two theorems are presented to prove that SR has some robustness to noises in the parallel array. These results further extend the applicability of SR in signal processing.

Reservoir information extraction using a fractional Fourier transform and a smooth pseudo Wigner-Ville distribution

Currently, it is difficult for people to express signal information simultaneously in the time and frequency domains when analyzing acoustic logging signals using a simple-time or frequency-domain method. It is difficult to use a single type of time-frequency analysis method, which affects the feasibility of acoustic logging signal analysis. In order to solve these problems, in this paper, a fractional Fourier transform and smooth pseudo Wigner Ville distribution （SPWD） were combined and used to analyze array acoustic logging signals. The time-frequency distribution of signals with the variation of orders of fractional Fourier transform was obtained, and the characteristics of the time-frequency distribution of different reservoirs under different orders were summarized. Because of the rotational characteristics of the fractional Fourier transform, the rotation speed of the cross terms was faster than those of primary waves, shear waves, Stoneley waves, and pseudo Rayleigh waves. By choosing different orders for different reservoirs according to the actual circumstances, the cross terms were separated from the four kinds of waves. In this manner, we could extract reservoir information by studying the characteristics of partial waves. Actual logging data showed that the method outlined in this paper greatly weakened cross-term interference and enhanced the ability to identify partial wave signals.

Classification analysis of microarray data based on ontological engineering

Background knowledge is important for data mining, especially in complicated situation. Ontological engineering is the successor of knowledge engineering. The sharable knowledge bases built on ontology can be used to provide background knowledge to direct the process of data mining. This paper gives a common introduction to the method and presents a practical analysis example using SVM (support vector machine) as the classifier. Gene Ontology and the accompanying annotations compose a big knowledge base, on which many researches have been carried out. Microarray dataset is the output of DNA chip. With the help of Gene Ontology we present a more elaborate analysis on microarray data than former researchers. The method can also be used in other fields with similar scenario.

Design of a 4.224GHz Quadrature LC-VCO

A 4. 224GHz quadrature voltage-controlled oscillator （QVCO） applied in MB-OFDM UWB synthesizers is implemented in 0.18μm RF-CMOS technology. An improved structure of the QVCO is presented for better phase noise. A novel configuration of a MOS varactor is designed for good linearity of K as well as a new digital capacitor controlled array topology with lower parasitic capacitance and lower Ron. Measurement results show a phase noise of - 90.4dBc/Hz at 100kHz offset and - 116.7dBc/Hz at 1MHz offset from a carrier close to 4. 224GHz. The power dissipation is 10. 55mW from a 1.8V supply.

浅析一道高考题

本文通过分析解决本题,从而导出一个更一般的结论,即用数字1,2,3,4,…,n形成数阵时,S=b1+b2+…+的一般通式,以供同行们商榷。

Min-norm spatial spectrum based on acoustic vector-sensor linear array

The high resolution of DOA（direction of arrival） estimation could be obtained by using the min-norm algorithm. In this paper, the expression of the min-norm spatial spectrum based on acoustic vector-sensor（AVS） linear arrays was presented and simulation study was carried out. Results of simulations indicated that left/right ambiguity could be removed and better performance for DOA estimation was obtainable when dealing with sources close to endfire than using pressure hydrophone linear arrays, and the interelement spacing was allowed to exceed the half-wavelength upper limit. A three-element vector hydrophone linear array with two meters interspace was designed. The AVS experiment was carried out at Songhua Lake in Jinlin Province. Experimental results show a high resolution tracking of targets can be obtained using the rain-norm algorithm.

3-D NUMERICAL COMPUTATION OF JET ARRAY IMPINGEMENT WITH INITIAL CROSSFLOW

The 3-D numerical computation of the flow and temperature fields for jet array impingement with initial crossflow investigates the effects of the jet-to-surface spacing, the impinging hole arrangement and the jet-to-crossflow mass flux ratio on heat transfer characteristics. The study shows that: (1) under the different jet-to-surface spacing, the impingement cooling with inline arrangement is better than that with staggered arrangement for a given jet-to-crossflow mass flux ratio;( 2 ) the value of jet-to-surface spacing impacts a complicated effect on the flow and heat transfer for jet array impingement; (3) as the ratio of crossflow-to-jet mass flux ratio increases, the cooling effectiveness on monotonous decrease for both inline and staggered arrangements at the same jet-to-surface spacing.

Digitalized Mirror Array and Its Application in Large Telescope:Principle and Case Studies

In this article, we report the principle and conceptual design of a fundamentally different technology in fabricating high precision aberration free optical devices. The tip-tilt of facet in a mirror array is produced by digitally controlled line-tilts of rows and columns. It has not only provided a cost-effective designing methodology in optical physics but also led to a much finer precision of 1 mili arc sec or less. As examples of the application of the proposed digitalised optics, two case studies have been given： a 10 m Schmidt telescope （off-axis） and an 8 m Cassegrain telescope （on-axis）.

The Sequential Continuity of Multiplication on a Class of Infinite Matrix Algebras

Let λ and μ are sequence spaces and have both the signed_weak gliding hump property, (λ,μ) be the algebra of the infinite matrix operators which transform λ into μ, in this paper, we study the strong? Mackey? weak multiplier sequentially continuous problem of infinite matrix algebras (λ,μ).

Linear Error Equation on Field F_2

In this paper, we will give a method to solve linear error equationon on F2, by using linear algebra on fields F2 and partition theory.

SS-SERA:An improved framework for architectural level soft error reliability analysis

Integrated with an improved architectural vulnerability factor （AVF） computing model, a new architectural level soft error reliability analysis framework, SS-SERA （soft error reliability analysis based on SimpleScalar）, was developed. SS-SERA was used to estimate the AVFs for various on-chip structures accurately. Experimental results show that the AVFs of issue queue （IQ）, register update units （RUU）, load store queue （LSQ） and functional unit （FU） are 38.11%, 22.17%, 23.05% and 24.43%, respectively. For address-based structures, i.e., levell data cache （LID）, DTLB, level2 unified cache （L2U）, levell instruction cache （LII） and ITLB, AVFs of their data arrays are 22.86%, 27.57%, 14.80%, 8.25% and 12.58%, lower than their tag arrays＇ AVFs which are 30.01%, 28.89%, 17.69%, 10.26% and 13.84%, respectively. Furthermore, using the AVF values obtained with SS-SERA, a qualitative and quantitative analysis of the AVF variation and predictability was performed for the structures studied. Experimental results show that the AVF exhibits significant variations across different structures and workloads, and is influenced by multiple microarchitectural metrics and their interactions. Besides, AVFs of SPEC2K floating point programs exhibit better predictability than SPEC2K integer programs.

Instability and Death of Spiral Wave in a Two-Dimensional Array of Hindmarsh-Rose Neurons

Spiral wave could be observed in the excitable media, the neurons are often excitable within appropriateparameters. The appearance and formation of spiral wave in the cardiac tissue is linked to monomorphic ventriculartachycardia that can denervate into polymorphic tachycardia and ventricular fibrillation. The neuronal system oftenconsists of a large number of neurons with complex connections. In this paper, we theoretically study the transitionfrom spiral wave to spiral turbulence and homogeneous state (death of spiral wave) in two-dimensional array of theHindmarsh-Rose neuron with completely nearest-neighbor connections. In our numerical studies, a stable rotating spiralwave is developed and selected as the initial state, then the bifurcation parameters are changed to different values toobserve the transition from spiral wave to homogeneous state, breakup of spiral wave and weak change of spiral wave,respectively. A statistical factor of synchronization is defined with the mean field theory to analyze the transition fromspiral wave to other spatial states, and the snapshots of the membrane potentials of all neurons and time series of meanmembrane potentials of all neurons are also plotted to discuss the change of spiral wave. It is found that the sharpchanging points in the curve for factor of synchronization vs. bifurcation parameter indicate sudden transition fromspiral wave to other states. And the results are independent of the number of neurons we used.

Bounds for Determinants of Quaternion Matrices

This paper improves and generalizes famous Fischer's inequality and Hadamard's inequality,gets precise estimation of bounds for the determinant of quaternion matrix.

A force feedback master finger in exoskeleton type

In order to eliminate the drawbacks of conventional force feedback gloves, a new type of master fin- ger has been developed. By utilizing three ＂four-bar mechanism joint＂ in series and wire coupling mecha- nism, the master finger transmission ratio is kept exactly 1：1.4：1 in the whole movement range and it can make active motions in both extension and flexion directions. Additionally, to assure faster data transmission and near zero delay in the master-slave operation, a digital signal processing/field programmable gate array （DSP/FPGA-FPGA） structure with 200μs cycle time is designed. The operating modes of the master finger can be contact or non-contact, which depends on the motion states of a slave finger, free motion or constrained motion. The position control employed in non-contact mode ensures unconstrained motion and the force control adopted in contact mode guarantees natural contact sensation. To evaluate the performances of the master finger, an experiment between the master finger and a DLR/HTT dexterous finger is conducted. The results demonstrate that this new type master finger can augment telepresence.

Normalization strategy of microarray gene expression data

Objective： To discuss strategies and methods of normalization on how to deal with and analyze data for different chips with the combination of statistics, mathematics and bioinformatics in order to find significant difference genes. Methods： With Excel and SPSS software, high or low density chips were analyzed through total intensity normalization （TIN） and locally weighted linear regression normalization （LWLRN）. Results： These methods effectively reduced systemic errors and made data more comparable and reliable. Conclusion： These methods can search the genes of significant difference, although normalization methods are being developed and need to be improved further. Great breakthrough will be obtained in microarray data normalization analysis and transformation with the development of non-linear technology, software and hardware of computer.