Time series modeling and spectrum analysis for chatter mode in endmilling dynamics

To analyze the chatter mechanics, the power spectrum of a time series method was analyzed by considering cutting and structural dynamics. In this study, several time series models such as AR (burg, least square, yule walker, geometric lattice, instrument variable), ARX (arx, iv4), ARMAX, ARMA, Box Jenkins, Output Error were modeled and compared with one another. Finally, it was proved that arx, armax and iv4 are more desirable and reliable algorithms than the others for the calculation of the chatter mode in the endmilling operation. The cutting forces Fx and Fz have more powerful effects on the chatter than Fy in the sense that there is no shifting or pseudo mode in the power spectrum.     

A CMOS ratio-independent and gain-insensitive algorithmicanalog-to-digital converter

This paper describes the design of a CMOS capacitor-ratio-independent and gain-insensitive algorithmic analog-to-digital (A/D) converter. Using the fully differential switched-capacitor technique, the A/D converter is insensitive to capacitor-ratio accuracy as well as finite gain and offset voltage of operational amplifiers. The switch-induced error voltage becomes the only major error source, which is further suppressed by the fully differential structure. The proposed A/D converter is designed and fabricated by 0.8 μm double-poly double-metal CMOS technology. The op-amp gain is only 60 dB and no special layout care is done for capacitor matching. Experimental results have shown that 14-b resolution at the sampling frequency of 10 kHz can be achieved in the fabricated A/D converter. Thus it can be used in the applications which require low-cost high-resolution A/D conversion     

Recurrence and death in non-small cell lung carcinomas: a prognostic model using pathological parameters, microvessel count, and gene protein products

Optimized stent expansion by high-pressure inflations of oversized balloons has initially been derived from experience obtained with the Palmaz-Schatz stent, whereas there is little experience with this strategy in the Wallstent. By using this approach with quantitative coronary angiographic guidance, 20 Wallstents and 20 Palmaz-Schatz stents were implanted in 34 patients and consecutively examined by conventional two-dimensional (2D) intracoronary ultrasound (ICUS) and three-dimensional (3D) ICUS on the basis of the application of a pattern recognition algorithm. Ultrasound criteria of adequate stent expansion were defined as a complete apposition of the stent to the vessel wall, a stent symmetry index (SSI = minimum/maximum lumen diameter) > or = O.7, and a stent-reference lumen area ratio (SRR = Minimum intrastent lumen area/Average of proximal and distal reference lumen area) > or = O.8. In all cases a smooth angiographic lumen and a negative diameter stenosis, on the basis of a distal reference, was achieved. For the Wallstents ICUS showed a higher SSI (2D, 0.95 +/- 0.04 vs 0.85 +/- 0.09; p < 0.001; 3D, 0.90 +/- 0.09 vs 0.82 +/- 0.11, p < 0.05) and a lower SRR (2D, 0.66 +/- 0.12 vs 0.81 +/- 0.13, p < 0.005; 3D, 0.63 +/- 0.14 vs 0.74 +/- 0.15, p < 0.05) than for the Palmaz-Schatz stents. Ninety percent of failure in meeting these criteria resulted from a low SRR. The incidence of incomplete stent apposition (one in both stents) or SSI <0.7 was low and generally associated with an SRR <0.8. The Wallstents met the ICUS criteria less often (2D, 2(1O%) vs 10(50%), p < 0.01; 3D, 3(15%) vs 9(45%), p < 0.05), were significantly longer (35.1 +/- 7.7 mm and 14.3 +/- 3.3 mm, p < 0.0001), and generally demonstrated a larger vessel tapering, measured as proximal minus distal ICUS reference lumen area (1.33 +/- 2.91 mm2 vs 0.44 +/- 1.97 mm(2), not significant). Wallstents meeting the ICUS criteria, however, showed less vessel tapering (0.18 +/- 1.64 mm(2)). Thus optimized stent expansion was followed by excellent angiographic results for both Palmaz-Schatz and Wallstent. Although angiographic results and visual assessment of the ICUS examination suggested a good outcome, few Wallstents met the ICUS criteria in contrast to the Palmaz-Schatz stents. The low value of the SRR in the Wallstents is likely to be caused by vessel tapering, suggesting that this criterion may be unsuitable in assessing the adequacy of the expansion of relatively long stents such as the Wallstent.     

准分子激光心血管治疗机的研究

研制了一台准分子激光心血管治疗机（ＸｅＣｌ３０８ｎｍ），单脉冲能量：８０－２００ｍＪ，平均功率５Ｗ，重复频率：手动单次，１－１００Ｈｚ，单次充气工作寿命：＞１０６脉冲数，脉冲－脉冲的能量不稳定度３％，激光脉宽１５０ｎｓ，光斑发散角（半角）：１．８×０．６ｍｒａｄ，光纤耦合输出＞２０ｍＪ。     

Study on phase behavior–impact strength relationship of unsaturated polyester/polyurethane hybrid polymer network

The phase behavior of a hybrid polymer network (HPN) composed of poly[(propylene glycol maleate)-co-(propylene glycol phthalate)] crosslinked with styrene and polyester–urethane crosslinked with methylene-bis-ortho-chloroaniline was examined. The correlation between phase separation and impact strength of the HPNs is discussed. The composition of HPNs has an effect on their properties.     

Efficient encoding of IEEE 802.11n LDPC codes

Addressed is the issue of LDPC coding for the emerging IEEE 802.11n standard. An efficient encoding algorithm is proposed. The algorithm is simple and easy to implement. The memory requirement is trivial     

图象信息与光电子技术

本文阐述图象信息的重要性，说明它与光电子技术的关系，包括图象信息的获取、传输、存储与显示，展望了未来。     

Synergistic interaction of D1 and D2 dopamine receptors in the modulation of the reinforcing effect of brain stimulation.

Rats were trained to press a bar for hypothalamic stimulation, and a frequency-response function was plotted. Quinpirole (a selective D2 agonist) facilitated self-stimulation when injected alone but failed to show the facilitatory effect when injected either 1 hr before or 1 hr after injection of SCH 23390 (a D1 antagonist). Injection of reserpine followed by α-methyl-p-tyrosine virtually eliminated self-stimulation. Subsequent injection of either SKF 38393 (a D1 agonist) alone or quinpirole alone did not restore self-stimulation, but a combination of quinpirole and SKF 38393 did. Results suggest that a D2 dopamine agonist facilitates the reinforcing effect of brain stimulation only if D1 receptors are activated by endogenous dopamine or by an exogenous agonist. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

铜及铜合金中铜量分析方法综述

现行标准ＧＢ５２３１－ＧＢ５２３５－８５中共有８８个合金牌号要求测定铜量，其含铜量从５３％到９９．９７％以上。本文就ＩＳＯ、ＧＢ和主要铜材生产企业分析规程中铜量测定方法，结合本人的实践经验进行综述。