C波段单片矢量调制器

报道了Ｃ波段单片矢量调制器的设计和制作。采用双栅场效应晶体管（ＤＧＦＥＴ）放大器作为控制器。偏置电路在芯片内。采用集总薄膜电容、电感、电阻作为匹配元件。采用离子注入、背面通孔接地、空气桥跨接等先进工艺技术。描述了ＤＧＦＥＴ器件Ｓ参数的提取步骤。两路放大器和９０°相移网络制作在３．１５ｍｍ×２．５ｍｍ×０．１ｍｍ的芯片上，同相功分器制作在１．６（１．８）ｍｍ×２．９ｍｍ×０．１ｍｍ的芯片上。电路可获得在０～８７°内连续变化的相移量，输出幅度可控。     

双栅极场发射阵列的特性模拟与设计

具有聚集能力的双栅极场发射阵列（ＤＧＦＥＡ）是两类最有发展前途的真空微电子器件（高分辨率场发射显示器和真空微电子微波，毫米波器件）的关键技术，本文简要比较了两种结构的ＤＧＦＥＡ的主要性能和优缺点，叙述了双层栅极结构ＤＧＦＥＡ的设计与模拟方法。从模拟计算获得的发射特性和聚焦性能可以看到，这种结构的ＤＧＦＥＡ能获得几乎平行的场发射电子束，其最大发射电流密度可达到约５００Ａ／ｃｍ＾２以上，是发展真空微电     

1．8GHz下功率密度为2．8W／mm的4H－SiC MES FET

１．８ＧＨｚ下功率密度为２．８Ｗ／ｍｍ的４Ｈ－ＳｉＣＭＥＳＦＥＴ据《ＩＥＥＥＥ．Ｄ．Ｌ．》第１５卷第１０期报道，ＣｈａｒｌｅｓＥ．Ｗｅｉｔｚｅｌ等已研制成一种４Ｈ－ＳｉＣＭＥＳＦＥＴ。采用４Ｈ－ＳｉＣ是由于它比６Ｈ－ＳｉＣ高出两倍的电子迁移率。器件的...     

金刚石薄膜场发射显示器

简要介绍了一般ＦＥＤ（场发射显示器）的工作原理,研究了非晶金刚石薄膜低场发射特点,讨论了金刚石薄膜制做场发射器的可行性;指出利用金刚石薄膜和阳极选择的方法可对Ｓｐｉｎｄｔ ＦＥＤ进行改进,从而使平面ＦＥＤ更容易实现。     

多层结构铁电薄膜的I—V特性性能的研究

为ＦＲＡＭ、ＦＦＥＴ和ＦＤＭ的实际应用研究，提出了多层结构铁电薄膜的设计思想，实际制备了Ｍ／ＢＩＴ／ｐ－Ｓｉ、Ｍ／ＰＺＴ／ＢＩＴ／ｐ－Ｓｉ、Ｍ／ＢＩＴ／ＰＺＴ／ＢＩＴ／ｐ－Ｓｉ三种结构铁电薄膜，并测量了它们的Ｉ－Ｖ特性曲线。结果表明，夹层结构铁电薄膜Ｍ／ＢＩＴ／ＰＺＴ／ＢＩＴ／ｐ－Ｓｉ漏电流密度Ｊ最小，在５００ｎｍ厚时Ｊ＋（＋３Ｖ）约２．８×１０－１０Ａ／ｍｍ２，Ｊ－（－３Ｖ）约１．２×１０－１２Ａ／ｍｍ２优于单层和双层结构铁电薄膜的结果。     

GaAs微微秒光导开关的研究

采用离子注入高纯ＬＥＣＧａＡｓ材料，设计研制了共面线和微带线两种结构微微秒（ｐｓ）光导开关．其输出电脉冲响应时ＩＮＦＷＨＭ为８—１０ｐｓ，当光强为１ｍＷ时，电脉冲幅度为０．２Ｖ     

GaAs微微妙光导开关的研究

采用离子注入高纯ＬＥＣ ＧａＡｓ材料，设计研制了共面线和微带线两种结构微微秒（ｐｓ）光导开关。其输出电脉冲响应时间ＦＷＨＭ为８－１０ｐｓ，当光强为１ｍＷ时，电脉冲幅度为０．２Ｖ。     

12GHz GaAs单片混频器

分析研究了一种新型１２ＧＨｚＧａＡｓＭＥＳＦＥＴ单片混频器，这种混频器采用级联ＦＥＴ作为混频元件。射频（ＲＦ）和本振（ＬＯ）信号分别通过各自的匹配网络进入混频电路，在中频输出端用中频缓冲放大器代替通常的中频匹配电路。电路在厚０．２ｍｍ，面积１．５ｍｍ×１．２ｍｍ的ＧａＡｓ基片上实现。设计的ＭＭＩＣ混频器在本振１１ＧＨｚ，射频１１．７～１２．２ＧＨＺ频率范围内的最大变频增益１．８ｄＢ。这一结果使进一步研究单片微波接收机成为可能。     

场发射显示技术

场发射显示器件（ＦＥＤ）正在成为新一代平板显示器件。本文简要介绍ＦＥＤ的发展历史，列举出ＦＥＤ与ＣＲＴ及ＬＣＤ相比的优点。介绍ＦＥＤ的工作原理、制作技术及其发展动态。还讨论了ＦＥＤ制作中的一些重要问题。     

PT／P（VDF—TrFE）复合膜及悬空结构热释电传感器研究

将溶胶－凝胶法制备的钛酸铅（ＰＴ）纳米粉粒掺入聚偏氟乙烯－三氟乙烯共聚物［Ｐ（ＶＤＦ－ＴｒＦＥ）］中，制成ＰＴ／Ｐ（ＶＤＦ－ＴｒＦＥ）复合热释电敏感膜，提高其热释电优值和探测优值。用ＫＯＨ腐蚀硅衬底使ＰＴ／Ｐ（ＶＤＦ－ＴｒＦＥ）敏感膜热释电传感器形成悬空结构。实验结果表明，掺入体积比为０．１２ＰＴ粉粒的ＰＴ／Ｐ（ＶＤＦ－ＴｒＦＥ）敏感膜，比同样成膜条件的Ｐ（ＶＤＦ－ＴｒＦＥ）膜的热释电优值提高２０％，探测优值提高３５％；悬空结构大大降低了热导，使传感器在低频段的电压灵敏度和电流灵敏度提高了１０倍以上。根据实验结果，提出了弱铁电体连续基体与铁电体颗粒均匀复合后，计算复合膜介电系数和热电系数的方法。     

A three-dimensional registration method for automated fusion of micro PET-CT-SPECT whole-body images

Micro positron emission tomography (PET) and micro single-photon emission computed tomography (SPECT), used for imaging small animals, have become essential tools in developing new pharmaceuticals and can be used, among other things, to test new therapeutic approaches in animal models of human disease, as well as to image gene expression. These imaging techniques can be used noninvasively in both detection and quantification. However, functional images provide little information on the structure of tissues and organs, which makes the localization of lesions difficult. Image fusion techniques can be exploited to map the functional images to structural images, such as X-ray computed tomography (CT), to support target identification and to facilitate the interpretation of PET or SPECT studies. Furthermore, the mapping of two functional images of SPECT and PET on a structural CT image can be beneficial for those in vivo studies that require two biological processes to be monitored simultaneously. This paper proposes an automated method for registering PET, CT, and SPECT images for small animals. A calibration phantom and a holder were used to determine the relationship among three-dimensional fields of view of various modalities. The holder was arranged in fixed positions on the couches of the scanners, and the spatial transformation matrix between the modalities was held unchanged. As long as objects were scanned together with the holder, the predetermined matrix could register the acquired tomograms from different modalities, independently of the imaged objects. In this work, the PET scan was performed by Concorde's microPET R4 scanner, and the SPECT and CT data were obtained using the Gamma Medica's X-SPECT/CT system. Fusion studies on phantoms and animals have been successfully performed using this method. For microPET-CT fusion, the maximum registration errors were 0.21 mm +/- 0.14 mm, 0.26 mm +/- 0.14 mm, and 0.45 mm +/- 0.34 mm in the X (right-left), Y (upper lower), and Z (rostral-caudal) directions, respectively; for the microPET-SPECT fusion, they were 0.24 mm +/- 0.14 mm, 0.28 mm +/- 0.15 mm, and 0.54 mm +/- 0.35 mm in the X, Y, and Z directions, respectively. The results indicate that this simple method can be used in routine fusion studies.     

CO2激光照射活体皮肤的光热效应研究

结合温度测量和数值模拟进行激光与组织光热效应的研究。采用二维有限元法求解生物热传输方程,可计算得到组织的模拟温度分布。温度测量可用来验证理论模型,采用微型热电偶与红外辐射测温仪同时测量生物组织内部和表面照射点温度,适于组织微创和快速的点温测量。CO2激光凝结活体大鼠皮肤组织的实验和数值分析结果显示温度响应曲线形状基本一致,表面照射点（r=0mm,z=0mm）和皮下（r=0mm,z=1mm）温度的峰值相对误差分别为23．24％和0．4％,灌注率和位置是温度曲线的主要影响因素,所以准确的组织参数和更精确的定位可以进一步降低误差,为激光治疗提供直观、全面和可预知的信息。     

新型L形梁压阻微加速度传感器

介绍了一种新型的基于MEMS体硅加工工艺的L形粱压阻微加速度传感器.在加工过程中采用Si-Si直接键合完成底板与传感器支撑框体之间的粘合,使得后续加工工艺更加简单;采用DRIE释放梁结构,从而保证了梁结构的完整性.分析了该传感器的结构参数和灵敏度,并用ANSYS进行了有限元模拟,同时介绍了其工艺流程,以及封装后的测试结果.芯片尺寸为3.8 mm×3.8 mm×0.82 mm,其中敏感质量块尺寸为2 mm×2 mm×0.4 mm,梁尺寸为2 200μm×100 μm×40μm.经初步测试,在采用5 V电源供电时灵敏度为0.5 mV/g左右,3 dB截止频率为520 Hz左右.     

光学胶膜液体可变焦微透镜阵列

微透镜阵列在光束匀化、波前测量、集成成像等领域有广泛应用。设计了一种基于光学胶膜(Optically Clear Adhesive, OCA)的液体可变焦微透镜阵列。采用矩形排列的硅微孔阵列控制单个透镜的孔径和排布,并以OCA光学胶膜和去离子水作为微透镜阵列的塑形材料。通过调整微流体腔内液体注入的体积实现对透镜焦距从1.46~10.44 mm的调整。依据聚焦与成像实验证实了微透镜阵列具有良好的均匀性。最后,将该微透镜阵列应用于激光光束匀化整形,通过一对微透镜阵列实现了光束匀化整形。进一步通过固定一对微透镜阵列的间距实现匀化光斑尺寸在7.2~8.4 mm内可调,为匀化光斑尺寸可调提供了新思路。     

空间相机次镜调整机构的性能评价及参数优化

针对空间相机次镜调整机构的复杂设计约束要求，提出一组评价调整机构运行效率的指标体系，并基于这组指标评价体系，优化得到一组综合约束下效率性能较高的机构尺寸参数。通过建立机构的运动学模型、运动误差模型、静力学模型和动力学模型，针对运载过程和在轨运行期间的约束要求，提出了空间利用效率指标、误差传递效率指标、质量受力效率指标和运动能耗效率指标，基于四个效率性能评价指标，利用性能图谱法，分别得到了四个效率指标的性能图谱，并进一步优化得到了一组效率性能全面的机构尺寸参数（a，b，l）=（197 mm，643 mm，1 260 mm），研究成果为后续该机构的空间工程应用奠定了良好的理论基础。     

炉管制程工艺中的片数效应及其优化方案

随着半导体技术的发展,越来越多的立式炉管在200mm及300mm集成电路晶圆制造中被应用到。同时炉管制程中的片数效应随着集成电路芯片的集成度越来越高而被凸显出来。文章将以LPCVD氮化硅在0.16μm、64M堆叠式内存制造过程中的片数效应为例,阐述炉管制程工艺中的片数效应以及通过调整制程参数（温度、沉积时间）的方式予以解决的实例。文中通过调整炉管上中下的温度来补偿气体的分布不均匀,调整沉积时间来补偿不同片数的沉积速率的差异,两者结合并辅以基于片数的分片程式来解氮化硅电介质沉积的片数效应。同时以此为基础总结出炉管片数效应的解决方案。     

小型宽光谱太阳光谱仪光学设计

针对大气层外的太阳光谱辐照度监测,设计了一种星载小型宽光谱太阳光谱仪。光学系统应用改进的切尔尼-特纳光学结构,工作波长范围为600~1 200 nm(二级光谱)和1 200~2 400 nm(一级光谱);一二级光谱使用二向色分光镜分离,并采用两片线阵探测器同时接收,实现全谱瞬态直读。整个光学结构的尺寸为80 mm55 mm20 mm。经过系统优化,全谱段子午方向像差低于6 m。基于惠更斯点扩散函数(PSF),仿真探测器像元的光谱响应函数(SRF),结果表明光谱分辨率在600~1 200 nm波段优于2 nm,在1 200~2 400 nm波段优于4 nm。系统结构简单紧凑,稳定性高,适合用于空间太阳光谱辐照度的在轨监测。     

Registered 3-D ultrasound and digital stereotactic mammography for breast biopsy guidance

Large core needle biopsy is a common procedure used to obtain histological samples when cancer is suspected in diagnostic breast images. The procedure is typically performed under image guidance, with freehand ultrasound and stereotactic mammography (SM) being the most common modalities used. To utilize the advantages of both modalities, a biopsy device combining three-dimensional ultrasound (3DUS) and digital SM imaging with computer-aided needle guidance was developed. An implementation of a stereo camera method was applied to SM calibration, providing a target localization error of 0.35 mm. The 3-D transformation between the two imaging modalities was then derived, with a target registration error of 0.52 mm. Finally, the needle guidance error of the device was evaluated using tissue-mimicking phantoms, showing a sample mean and standard deviation of 0.44 +/- 0.22 and 0.49 +/- 0.27 mm for targets planned from 3DUS and SM images, respectively. These results suggest that a biopsy procedure guided using this device would successfully sample breast lesions at a size greater than or equal to the smallest typically detected in mammographic screening (approximately 2 mm).     

基于小波变换的苹果汁多光程近红外光谱信息提取研究

利用浸入式光纤采集鲜榨苹果汁分别在5mm、10mm、15mm和20mm光程下的透/反射近红外光谱,实现对苹果汁中糖度(可溶性固形物,SSC)和酸度(pH值)的定量预测.结果表明,SSC和pH具有不同的最佳光程长,分别为5mm和20mm.为了兼顾各待测量对象的浓度范围和各组分的最佳光程长,从而提高模型的性能,采用多光程光谱混合建模,研究了多光程光谱信息的提取方法.采用原始光谱直接展开所建的模型虽然能有效利用多光程光谱的信息,但增加了模型复杂度,致使建模时间增长.因此,提出了两种基于小波变换的信息提取方法,它们在高效提取多光程信息的同时,能显著缩短建模时间并简化模型.其中基于展开光谱的小波近似系数建立的模型性能最优,SSC和pH值模型的SECV值分别达到0.4761oBrix和0.0779.     

Surface emitting characteristics of silicon waveguides

This paper concerns the surface emitting characteristics of silicon waveguides in the millimeter-wave frequency band. The waveguides used in the experiment are rectangular slabs of high resistivity silicon (30,000 ohm-cm). A series of periodic perturbations on the waveguide surface provide a radiating antenna. A rectangular grating with a period of Λ=1.8 mm, a height of 0.35 mm, and a duty cycle of 0.46 was sawn into the top surface of a silicon waveguide with a width of 3 mm and a height of 1.41 mm. Experiments were performed to measure the attenuation, dispersion and the radiation characteristics of the waveguides. The test setup was used to monitor the frequency, radiation angle, and the radiated power. Measurements are made over a band of frequencies around the second Bragg frequency. The detector was scanned from 88–95 GHz and changes were observed in the attenuation constant, dispersion relation and the far field radiation pattern. From these results we were able to verify the grating theory.