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A new algorithm for overcoming the problem of incidental cancellation and improving the convergence behaviour of large partially adaptive arrays is proposed and investigated. The algorithm uses an auxiliary adaptive source tracker to separate individual sources in the environment before using the resulting outputs to cancel unwanted jamming picked up through the main beam of the system. Because the source tracker's outputs are roughly orthogonal in the steady state and the positions of sources of significant powers are available, the algorithm possesses fast convergence behaviour and solves the problem of incidental cancellation in the most natural manner by adding back the desired signal to the canceller output if the former is cancelled during the adaptation process. In addition, the algorithm has about the same computational complexity as partially adaptive generalized sidelobe cancellers using steepest descent based algorithms. 相似文献
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传统中药是现代生活健康的宝库,其功效在保健及慢性疾病的治疗方面尤其显著,并已备受世界重视.要成功将中药引进世界市场,最基本要求是要从科学方法去证明其效用及安全性;更重要是依从传统中医学对复方应用的要求去作研究.本文陈述了我们对传统中药古方"生脉散"研究及开发抗氧化健康食品的经验.透过现代生化及药理技术,我们发现"生脉散"中的五味子含丰富的抗氧化活性成分,为传统中医学利用"生脉散"治疗心脏病提供了理论依据. 相似文献
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A simple model is presented for the negative drain current transients observed in GaAs MESFETs when subjected to ionizing radiation. The two dominant mechanisms are proposed to be electron trapping under the Schottky gate and in the neutral semi-insulating substrate. The model is suitable for the design and evaluation of radiation-resistant GaAs MESFET integrated circuits using common electrical simulators such as SPICE3. 相似文献
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The extinction point of spinach was <0.4% but above 0.2% O2 at 0° and 5°C. Respiration rates were ~2.3 times greater at 5°C than at 0°C and were similar among cultivars. In 0.8% O2 atmosphere, O2 uptake of three cultivars was reduced by an average of 53% and CO2 production was reduced by 35% relative to those stored in air. Deterioration of leaves was reduced by 30 to 54%, while weight loss, color and chlorophyll content were not affected by the 0.8% O2 atmosphere. Thus O2 could be allowed to be depleted to 0.8% in modified atmosphere packaging without quality loss due to anoxia. 相似文献
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通过测定32种多硝基芳烃的静电火花感度,建立了50%发火能量EES与爆速平方值的关系式。试式不仅体现出Evans-Planyi-Semenov关系,而且 起爆、初始分解或由静电火花引起的能量转换过程中多硝基化合物分子初始分裂时化学是的同一性。但电火花能转至分子反应中心的方式还不茂清楚 相似文献
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To clean the exhaust emissions as one of the most important tasks in pollution control, a study on the treatment of engine emissions with discharge assistance was reported. A DBD plasma source shaped in grid and cylinder was examined in different engine operational modes to reduce the NOX content of diesel engine exhaust. The composition of the exhaust gases and chemical reactions initiated by the discharge were analyzed. The discharge frequency had a crucial impact on the device’s performance and gas treatment. The voltages applied to the discharge gap could alter the chemical reactions occurring in the treated gases, which were indicated by the NO to NO2 ratio. The operation of the system was studied at frequencies ranging from 400 Hz to 16 kHz. 相似文献
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A Mustonen HK Ploos van Amstel R Berger MK Salo L Viinikka KO Simola 《Canadian Metallurgical Quarterly》1997,17(10):964-966
Presentation of 11 cases of retroperitoneal sarcoma. Mean time from the beginning of symptoms to diagnosis is 6 months. The primary complementary study is CT. Surgery was performed in all cases, using complete resection in 6 cases, and partial resection in 5. Ten patients relapsed. 9 of which were treated with surgical rescue, in one or more occasions; chemotherapy was added in 6 cases and radiotherapy in 7. Survival at five years is 68%, with a mean follow-up of 66 months. 相似文献