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The Hong Kong Mass Transit Railway Corporation has undertaken a major project to replace its automatic train control system with a new generation system. The recent changes in railway atmosphere around the world have prompted the MTRC to establish a safety management system for the operation and maintenance of its railway. The MTRC also understands its responsibility for the safe operation of the railway and has a strong commitment to safety. This article describes the MTRC safety-critical project management system and the project safety report which documents all the related safety activities carried out by participating parties of the project  相似文献   
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主要介绍了0.68THz和1.00 THz频段平衡式三倍频。该三倍频是基于反向平衡式二极管和石英基片完成,而非集成电路。该工作主要的贡献在于提高了二极管等效电路模型,该二极管模型不仅仅包括I/V和C/V,同时还加入了等离子体共振和趋肤效应,将薄膜电路减薄至15um,机械加工精度提高至3um内,可使工作频率提高至1.2THz。通过场路协同仿真,利用高精度太赫兹装配工艺,最终实现工作频率为0.68THz和倍频效率为1%的三倍频器,工作频率为1.00 THz和倍频效率为0.6%的三倍频器,输出相对带宽均大于10%。  相似文献   
3.
This paper presents a high dynamic range programmable gain amplifier (PGA) with linear-in-dB and digital to analog converter (DAC) gain control using a BiCMOS process. The proposed PGA is composed of a folded Gilbert variable gain amplifier cell, a DC offset cancellation circuitry, two inductorless fixed gain amplifiers with bandwidth extension, a symmetrical exponential voltage generator, a novel buffer amplifier with active inductive peaking for testing purposes and a 10 bit R-2R DAC. The linear-in-dB and DAC gain control scheme facilitate the analog baseband gain tuning accuracy and stability, which also provides an efficient way for digital baseband automatic gain control. The PGA chip is fabricated using 0.13 μm SiGe BiCMOS technology. With a power consumption of 80 mA@1.2 V supply voltage, the fabricated circuit exhibits a tunable gain range of ? 30–27 dB (DAC linear gain step guaranteed), a 3 dB bandwidth of around 3.5 GHz and a gain resolution of better than 0.07 dB.  相似文献   
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Between August 1990 and August 1995, 231 patients (median age 51, 53% Durie-Salmon stage III, median serum beta-2-microglobulin 3.1 g/L, median C-reactive protein 4 g/L) with symptomatic multiple myeloma were enrolled in a program that used a series of induction regimens and two cycles of high-dose therapy ("Total Therapy"). Remission induction utilized non-cross-resistant regimens (vincristine-doxorubicin-dexamethasone [VAD], high-dose cyclophosphamide and granulocyte-macrophage colony-stimulating factor with peripheral blood stem cell collection, and etoposide-dexamethasone-cytarabine-cisplatin). The first high-dose treatment comprised melphalan 200 mg/m2 and was repeated if complete (CR) or partial (PR) remission was maintained after the first transplant; in case of less than PR, total body irradiation or cyclophosphamide was added. Interferon--2b maintenance was used after the second autotransplant. Fourteen patients with HLA-compatible donors underwent an allograft as their second high-dose therapy cycle. Eighty-eight percent completed induction therapy whereas first and second transplants were performed in 84% and 71% (the majority within 8 and 15 months, respectively). Eight patients (3%) died of toxicity during induction, and 2 (1%) and 6 (4%) during the two transplants. True CR and at least a PR (PR plus CR) were obtained in 5% (34%) after VAD, 15% (65%) at the end of induction, and 26% (75%) after the first and 41% (83%) after the second transplants (intent-to-treat). Median overall (OS) and event-free (EFS) survival durations were 68 and 43 months, respectively. Actuarial 5-year OS and EFS rates were 58% and 42%, respectively. The median time to disease progression or relapse was 52 months. Among the 94 patients achieving CR, the median CR duration was 50 months. On multivariate analysis, superior EFS and OS were observed in the absence of unfavorable karyotypes (11q breakpoint abnormalities, -13 or 13-q) and with low beta-2-microglobulin at diagnosis. CR duration was significantly longer with early onset of CR and favorable karyotypes. Time-dependent covariate analysis suggested that timely application of a second transplant extended both EFS and OS significantly, independent of cytogenetics and beta-2-microglobulin. Total Therapy represents a comprehensive treatment approach for newly diagnosed myeloma patients, using multi-regimen induction and tandem transplantation followed by interferon maintenance. As a result, the proportion of patients attaining CR increased progressively with continuing therapy. This observation is particularly important because CR is a sine qua non for long-term disease control and, eventually, cure.  相似文献   
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