数字示波器采集数据

尽管高频通讯模式如Zigbee和千兆以太网受到大量的关注,但很多工程师仍需要诸如示波器这样的工具来帮助他们测试和调试频率在500 MHz以下的设备.在此带宽范围内的新的"低端"示波器提供了扩展功能,可以帮助工程师们轻而易举地解码串行数据流及查看测试结果.有些示波器还包括混合信号的功能来辅助开发人员同时观测数字和模拟信号.     

采用模块简化网络连接

许多系统都使用以太网,特别是TCP/IP,来与其他装置、主控计算机或者远程网络进行通信.如今,开发人员不再费劲地去掌握复杂的传输控制协议(TCP)和互联网协议(IP)以及编写自己的类ISO堆栈,而是利用可以立即使用的芯片、模块和软件.这些商业化的产品提供了以太网的物理连接以及简化通信的软件.     

电池的扁平化趋势

在计划开发微型化、工作功耗小的便携式电子装置时,新型扁平化、采用薄膜的电池技术具有巨大的潜力.     

自己动手,实现隔离

我曾经在工作中遇到过仪器产生异常且不可复制结果的情况.对仪器信号的分析结果表明其受到按地环路所导致的60Hz噪音的影响.这个回路产生于曲折的接地路线--经所在建筑物的电力线路从仪器接到我的数据采集计算机.     

Human micro-vascular endothelial cell seeding on Cr-DLC thin films for mechanical heart valve applications

In this investigation, chromium modified diamond-like-carbon (Cr-DLC) films were studied for potential applications in mechanical heart valves. Three Cr- DLC samples were prepared using a magnetron sputtering technique employing an intensified plasma assisted processing (IPAP) system. The three samples consisted of the following Cr content: 1 at.%, 5 at.% and 10 at.%. The biological response of human micro-vascular endothelial cells (HMV-EC) seeded on Cr-DLC films was evaluated in terms of initial cell attachment and growth. The Cr-DLC films were characterized using Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), secondary ion mass spectroscopy (SIMS) and by the contact angle technique. Endothelial cell adhesion and growth was found to be affected by changing the Cr content of Cr-DLC films.     

Nitrogen and hydrogen related infrared absorption in CVD diamond films

In this paper, we investigate on the presence of hydrogen and nitrogen related infrared absorptions in chemical vapour deposited (CVD) diamond films. Investigations were carried out in cross sections of diamond windows, deposited using hot filament CVD (HFCVD). The results of Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) and Raman spectroscopy carried out in a cross section of self-standing diamond sheets are presented. The FTIR spectra showed several features that have not been reported before. In order to confirm the frequency of nitrogen related vibrations, ab-initio calculations were carried out using GAMESS program. The investigations showed the presence of several C-N related peaks in one-phonon (1000-1333 cm^− 1). The deconvolution of the spectra in the three-phonon region (2700-3150 cm^− 1) also showed a number of vibration modes corresponding to sp^mCH_n phase of carbon. Elastic recoil detection analysis (ERDA) was employed to compare the H content measured using FTIR technique. Using these measurements we point out that the oscillator strength of the different IR modes varies depending upon the structure and H content of CVD diamond sheets.     

Causes of sudden unexpected cardiac death in the first two decades of life

Sudden, unexpected cardiac death in the age group 1 to 21 years usually is due to myocarditis, hypertrophic cardiomyopathy, aortic valvar stenosis, and coronary arterial abnormalities. The hearts of 70 patients <21 years of age who died suddenly were reviewed. Twenty patients were <1 year of age and 50 were 1 to 21 years old. The cardiac findings were compared with those in 68 age-matched controls with known cardiac disease who did not die suddenly. Significant cardiac abnormalities were present in 13 (65%) of the 20 infants; 10 (50%) had anomalies of the aortic origin of the coronary arteries. Among the 50 older patients, cardiac abnormalities were found in 40 (80%), among whom coronary arterial anomalies existed in 12 (24%). Anomalies of aortic origin more frequently involved the left main than the right coronary artery in both groups.     

Intracellular motility: how can we all work together?

Recent results reinforce the view that actin-based and microtubule-based motility systems do not operate independently, but are used in coordinated fashion to determine intracellular localization of cargo such as organelles.     

Nanocrystalline diamond on SiO2 fiber: A new class of hybrid material

We report a template technique for the fabrication of high density nanocrystalline diamond (NCD)-coated silica (a-SiO₂) nanofibers with diameters of 1–5 μm. This method includes the synthesis of templates (a-SiO₂ nanofibers) by conventional Vapor–Liquid–Solid method and the conformal coating of the nanofibers with nanodiamond by Microwave Plasma Chemical Vapor Deposition technique in hydrogen-deficient conditions. A detailed micro-structural analysis was performed to probe the interaction of the NCD grains with a-SiO₂ nanofibers. The specimen for Transmission Electron Microscopy was prepared using Focused Ion Beam lift-out method. Room temperature micro-Raman was performed to study the crystalline quality of the NCD-coated silica nanofibers. Field electron emission of as-synthesized NCD-coated silica nanofibers was observed with a threshold field of ~ 3 V/µm.     

Lumbar spine fusion by local gene therapy with a cDNA encoding a novel osteoinductive protein (LMP-1)

STUDY DESIGN: A posterior arthrodesis animal model using local expression of a newly discovered osteoinductive protein delivered in bone marrow cells. OBJECTIVE: To introduce the concept of local gene therapy and determine its feasibility for achieving lumbar spine fusion using a gene for a novel osteoinductive protein: LIM Mineralization Protein-1 (LMP-1). SUMMARY OF BACKGROUND DATA: Extensive work is currently underway to improve the healing success and morbidity associated with the gold standard bone-grafting material of autogenous iliac crest. As a result, alternative osteoinductive proteins and new delivery methods warrant investigation. The authors' laboratory recently identified a novel gene that had osteoinductive capacity in vitro and is therefore a candidate for a new in vivo osteoinductive agent. METHODS: Single-level posterior lumbar and thoracic arthrodesis was attempted in 14 athymic rats. The graft material, which consisted of a devitalized bone matrix (no osteoinductive activity) soaked with 0.75 to 1.5 million bone marrow cells, was inserted with the dorsal spine exposed. In each rat, one site received marrow cells transfected with the cDNA encoding a novel osteoinductive protein. At the other site for a control, the marrow cells were transfected with the reverse copy of the cDNA that did not express any protein. Transfection of marrow cells for 2 hours was accomplished using the mammalian expression vector pCMV2. Rats were killed after 4 weeks, and the spines were evaluated by manual palpation, radiographs, and nondecalcified histology. RESULTS: In the pivotal experiment, successful spine fusion was obtained in 9/9 (100%) of the sites receiving marrow cells transfected with the active LMP-1 cDNA and in 0/9 (0%) of the sites receiving marrow cells transfected with the reverse (inactive) LMP-1 cDNA. Radiographs and histology confirmed the manual palpation results, demonstrating controlled new bone formation in the carrier and marrow transfected with the active LMP-1 cDNA and essentially no bone induction in the sites treated with marrow cells that did not express the protein. CONCLUSIONS: These data confirm that local delivery of the novel LMP-1 cDNA using bone marrow cells is feasible in vivo. Furthermore, these results demonstrate that posterior thoracic or lumbar spine fusion can be achieved in rats by local delivery of the LMP-1 cDNA.