两个回归函数相等的Bootstrap检验

两个回归参数相等性检验一直是统计界感兴趣的问题之一．在这篇文章中，四个检验统计量被用于度量两曲线的差异，在原假设下统计量的分布采用向量数据的重复抽样来逼近，并给出了—些模拟结果．     

Room temperature characterization of Hg1-xCdxTe P-on-n heterostructure photodiodes

Measurements of 77K R_oA and 300K reverse bias dynamic impedance (R_dA) products at one volt reverse bias has been carried out to assess the degree of correlation of this figure of merit. Planar P-on-n heterostructures were grown on near lattice-matched CdZnTe substrates with Hg_1-xCd_xTe (0.20< x <0.30) by molecular beam epitaxy. These devices were passivated with CdTe and doped with indium and arsenic as n- and p-type dopants, respectively. Current-voltage characteristic of these devices exhibit thermally generated dark currents at small and modest reverse bias. We have observed that R_oA values of these long wavelength infrared P-on-n heterostructure photodiodes at 77K correlate with room temperature R_dA values. Diode arrays with high room temperature R_dA values at one volt reverse bias also have high R_oA values at 77K. Similarly, low R_dA values at room temperature indicate poor performance at 77K where deviation from diffusion current occurs at reverse bias of 0.2 to 1 volt at room temperature. The results presented here, for a small samples of devices, demonstrate that room temperature measurements of current-voltage characteristics to evaluate Hg_1-xCd_xTe (0.22< x <0.28) diode performance and array uniformity at lower temperatures can be used. This provides an acceptable criteria for further study at lower temperatures.     

Differentiability of the Value Function of Nonclassical Optimal Growth Models

We consider an optimal growth (multi-sector) model with nonconvex technology. Using the Clarke results on generalized gradients, we prove that the value function has left and right derivatives with respect to the initial capital stock, without requiring supermodularity assumptions.     

Photodiffraction in InGaAs/InGaAsP multiple quantum wells enclosed in a microcavity

We report new results on the diffraction properties of photoinduced gratings in InGaAs/InGaAsP MQW structures. The original feature of this device is that the QWs are enclosed in an asymmetric Fabry–Perot microcavity in order to increase the diffraction efficiency. We observe oscillations in the diffraction efficiency due to resonant effects in the microcavity. The experimental spectra are compared with theory. Diffraction efficiency at 1.55 μm attains a maximum value of 2.7% at a write beam fluence of 260 μ J cm⁻², and then decreases at higher fluences. We explain this phenomenon by an absorption saturation at high excitation.     

A new actigraph for long-term registration of the duration andintensity of tremor and movement

Actigraphy, the long-term measurement of human movement with a small solid state recorder, is gaining acceptance as a useful method in many research fields. Currently available actigraphs assess or estimate the movement duration per time interval. However, the output gives no information on movement type or intensity, and cannot be used in subjects suffering from tremor. The present paper describes a new type of actigraph, that has been developed primarily for the long-term evaluation of motor symptoms in Parkinson patients. The device is the first to discriminate tremor from other movements and to assess both duration and intensity of the two types of movement. It is based on a Motorola 68HC805B6 microcontroller and contains: an accelerometer, programmable gain stages, programmable low- and highpass filters, a programmable level comparator, a peak detector, interface circuits, a real time clock, data storage, and control circuitry. The micro-controller performs a period amplitude sequence analysis (PASA) on the conditioned accelerometer signal, and stores four output variables (tremor duration, tremor amplitude, movement duration, and movement amplitude) at the end of programmable time intervals. The analysis of fluctuations in the motor symptoms of, e.g., Parkinson patients using this actigraph can be of great help in the pharmacological management of symptoms     

一种漂移室定位子性能反常现象的研究

研究了一种漂移室定位子性能的反常现象,它关系到定位子的使用寿命．着重测量了暗电流和随机噪声与时间、高压及温度的关系.     

The Transmogrifier-2: a 1 million gate rapid-prototyping system

This paper describes the Transmogrifier-2 (TM-2), a second-generation multifield programmable gate array (FPGA) rapid-prototyping system. The largest version of the system will comprise 16 boards that each contain two Altera 10K50 FPGA's, four I-Cube interconnect chips, and up to 8 Mbytes of memory. The inter-FPGA routing architecture of the TM-2 uses a novel interconnect structure, a nonuniform partial crossbar, that provides a constant delay between any two FPGA's in the system. The TM-2 architecture is modular and scalable, meaning that systems of various sizes can be constructed from copies of the same board, while maintaining routability and the constant delay feature. Other features include a system-level programmable clock that allows single-cycle access to off-chip memory, and programmable clock waveforms with edge resolution of 10 ns. The first Transmogrifier-2 boards have been manufactured and are functional. They have recently been used successfully in some simple graphics acceleration applications