后路经椎弓根椎体楔形截骨矫形治疗胸腰椎陈旧性骨折伴后凸畸形

目的：探讨后路经椎弓根椎体楔形截骨矫形治疗胸腰椎陈旧性骨折伴后凸畸形的临床疗效。方法：回顾性分析我科于2006年1月至2010年10月收治的胸腰椎陈旧性骨折伴后凸畸形患者23例,男15例,女8例;年龄23岁至88岁;胸113例,胸127例,腰19例,腰24例;胸腰段（胸10~腰2）后凸畸形Cobb角为32°至66°,平均为46°±2.4°;伤椎后凸Cobb角为16°至42°,平均30°±1.8°。术前神经损伤程度按照ASIA分级：C级3例,D级11例,E级9例;腰背痛VAS评分平均7.84±0.28。23例患者均采用经椎弓根椎体楔形截骨矫形、减压、椎弓根钉系统内固定植骨融合手术治疗。结果：术后胸腰段后凸Cobb角平均12°±1.7°,矫正率74%;伤椎Cobb角为0°至4°,平均2.8°,矫正率91%;术后随访X片,胸腰段Cobb角矫正丢失角度不明显（2°至5°）。术后神经功能ASIA分级：3例C级2例改善至E级,1例为D级;11例D级均改善至E级;腰背痛VAS评分平均为2.9±0.13;内固定物无松动或断裂,无假关节形成等并发症。结论：后路经椎弓根椎体楔形截骨矫形治疗胸腰椎陈旧性骨折伴后凸畸形可重建胸腰段矢状面生理曲度,改善临床症状。     

Comparison of spatial compositional uniformity and dislocation density for organometallic vapor phase epitaxial Hg1−x CdxTe grown by the direct alloy and interdiffused growth processes

Etch pit density and spatial compositional uniformity data are presented for organometallic vapor phase epitaxial Hg_1−x Cd_x Te grown by the direct alloy and interdiffused growth methods. For alloy growth, composition variation is as low as Δx=0.004 and 0.02 over 2- and 3-in diam areas, respectively; while for growth on CdZnTe substrates, etch pit density values lower than 2×10⁵ cm⁻² have been achieved. For interdiffused growth on CdZnTe, etch pit density values lower than 5×10⁵ cm⁻² have been obtained, while the composition variation is usually Δx≤0.004 and 0.014 over 2- and 3-in diam areas, respectively. Data demonstrate that the choice of particular CdZnTe substrate strongly affects the subsequent etch pit density measured in the layer. Reasonably uniform n-type doping over 3-in diam area using the source triethylgallium is also reported for both growth methods.     

小儿先心病中EEG和RAEP的临床评价

目的 :评价先心病儿脑电图 (EEG)、脑干听觉诱发电位 (BAEP)的变化。方法 :对 3 0例先心病儿童EEG、BAEP的变化进行对比观察 ,并以 3 0名健康儿童为对照组。结果 :1.EEG :发绀组 (CCHD)异常率为 80 %( 8/ 10 ) ,非发绀组 (NCCHD)异常率为 3 0 %( 6/ 2 0 ) ,差异显著 (P <0 .0 5 )。2 .BAEP :CCHD组异常率为 10 0 %( 10 / 10 ) ,NCCHD异常率为 65 %( 13 / 2 0 ) ,差异显著 (P<0 .0 5 ) ,Ⅴ波潜伏期 (PL)、Ⅲ -Ⅴ、Ⅰ -Ⅴ波峰间潜伏期 (IPL)先心病患儿与对照组比较 ,CCHD组显著延长 (P <0 .0 5 )。 3 .EEG与BAEP :EEG异常者BAEP均异常 ( 10 0 %) ,EEG正常者BAEP有 5 6.3 %异常。结论 :1、先心病患儿伴有脑功能异常 ,CCHD较NCCHD显著。 2、EEG与BAEP均可反映脑功能异常改变 ,但非完全同步 ,BAEP似乎较为敏感。     

二维及三维超声成像在先天性子宫畸形诊断中的应用

目的:分析二维及三维超声成像在先天性子宫畸形诊断中的临床应用。方法:二维超声常规检查时,对可疑有先天性子宫畸形的病例进行经阴道三维超声扫查,并联合二维超声检查结果综合分析。结果:经阴道二维超声成像获得明确子宫畸形诊断的41例,经阴道三维超声成像获得明确子宫畸形诊断的61例,二者联合获得较明确子宫畸形诊断的64例。结论:二维及三维超声成像联合能够得到子宫外形轮廓和子宫腔准确、全面的信息,较准确地诊断先天性子宫畸形,特别是三维超声冠状切面成像在子宫畸形的分类、鉴别诊断及指导临床治疗中,起着非常重要的作用。     

Cathodoluminescence wavelength imaging for spatial mapping of excitons bound to dislocations and structural defects in cds

By means of the unique technique of cathodoluminescence wavelength imaging we analyse the distribution and nature of dislocations in strain-distorted CdS by scanning the spatial pattern of a set of lines due to excitons bound to dislocation-related defects. The method is demonstrated to be most powerful for the study of dislocations in II–VI and other materials which play a crucial role in hetero-epistructures.     

下颌升支矢状劈开截骨术与下颌角整形术同期进行的骨愈合动物实验研究

目的：通过对兔同期行下颌骨切开术与咀嚼肌剥离术,模拟下颌升支矢状劈开截骨术与下颌角整形术同期手术,对比观察术后骨愈合情况,从而推测其可行性。方法：选取18只健康新西兰大白兔,随机分为3组,实验组（n=8）一侧行下颌骨切开术与咀嚼肌剥离术同期手术,对侧不手术：对照组（n=8）一侧行下颌骨切开术,对侧不手术;正常对照组（n=2）不行任何手术。对比观察术后2、4、8、12周手术侧骨愈合情况。结果：实验组与对照组骨愈合过程相似,12周时各组兔骨小梁矿化度无显著差异。结论：下颌骨切开术与咀嚼肌剥离术同期进行,其术后骨断端达到骨性愈合,具有可行性。     

Combined Tuning of RF Power and Medium Access Control for WLANs

Mobile communication systems, such as handhelds and laptops, still suffer from short operation time due to limited battery capacity. We exploit the approach of protocol harmonization to extend the time between battery charges in mobile devices using an IEEE 802.11 network interface. Many known energy saving mechanisms only concentrate on a single protocol layer while others only optimize the receiving phase by on/off switching. We show, that energy saving is also possible during the sending process. This is achieved by a combined tuning of the data link control and physical layer. In particular, harmonized operation of power control and medium access control will lead to reduction of energy consumption. We show a RF power and medium access control trade-off. Furthermore we discuss applications of the results in IEEE 802.11 networks.     

Design procedure for two-stage CMOS opamp with optimum balancing of speed,power and noise

This article presents a basic two-stage CMOS opamp design procedure that provides the circuit designer with a means to establish optimised balancing between speed, power and noise for a given load condition. The proposed design steps allow opamp designers to optimise the power consumption for the given constraints of settling time, accuracy, noise and load. The key factor is to establish the optimum combination of ratios of transconductance of second stage to first stage and load capacitor to compensation capacitor. So, required accuracy and settling time can be established with minimum power consumption. Unlike the earlier reported design procedures, in this article a systematic method is presented to set the quiescent voltages at the transistors of the first and second stages of the opamp. This work will be helpful to select appropriate method of implementation of Miller compensation for given constraints. To verify the viability of the proposed design steps, SPICE simulation results for the proposed procedure are given. Best simulation results obtained on Tanner tool show settling time and power dissipation equal to 320 ns and 188.5 μW, respectively, for 5 pf capacitive load.     

A robust and fast procedure for the determination of the small signal equivalent circuit of HEMTs

In this paper we present an analytical, fast, accurate and robust technique for the determination of the circuit model elements of HEMTs in the microwave range. By this method the values of the equivalent circuit parameters of the device under test are extracted using three measured scattering (S) parameter sets without any optimization. We also investigated the influence of the reverse transfer conductance Re(Y₁₂) on the modelling by means of a gate drain resistance R_dg. The validity of this method was verified upon a set of pseudomorphic HEMTs having different gate widths tested on wafer at several bias and temperature conditions. Very good agreement between the simulated and measured S-parameters has been obtained. The procedure has been implemented in Agilent VEE language as a fully automated tool to allow an accurate, fast and complete device characterization requiring no operator supervision.     

瑞利-拉曼-米氏激光雷达光学接收和信号检测设计

研制了一台探测大气温度、气溶胶、卷云的瑞利-拉曼-米氏激光雷达(RRML),介绍了激光雷达的设计方法,基于单片机实现了光电倍增管门控电路.通过数值模拟计算大气后向散射回波信号,分析仿真信号的特征,作为激光雷达设计的参考.通过设计合理的接收光路,采用极高灵敏度的R4632光电倍增管以及微弱信号光子计数技术,提高瑞利和拉曼微弱信号的信噪比(SNR).为了实现瑞利-拉曼-米氏激光雷达对大气气溶胶和卷云的联合探测,532 am回波信号采取高低分层技术,通过对气溶胶和卷云的回波光加衰减和探测器门控两种手段相结合,保证了R4632光电培增管极高的灵敏度探测器对大气气溶胶和高层卷云回波信号的线性检测,从而实现一台激光雷达对大气温度、气溶胶和卷云的探测.试验表明,信号检测单元的设计满足测量精度的要求.