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Search Results: 1 - 10 of 210946 matches for " 赵东林 "
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纳米Si/C/N复相粉体的微波吸收特性
,周万城
复合材料学报 , 2002,
Abstract: 采用双反应室激光气相合成纳米粉体装置,以六甲基二硅胺烷((Me3Si)2NH)(Me:CH3)为原料合成了纳米Si/C/N复相粉体,粒径为20nm~30nm。研究了纳米Si/C/N复相粉体在8.2GHz~18GHz的微波吸收特性,结果表明:纳米Si/C/N复相粉体介电常数的实部(ε')和虚部(ε″)在8.2GHz~18GHz随频率增大而减小,介电损耗(tgδ=ε″/ε')较高,是较为理想的微波吸收材料;纳米Si/C/N复相粉体在不同基体中的微波吸收特性出现很大差异。纳米Si/C/N复相粉体中的SiC微晶固溶了大量的N原子,形成大量带电缺陷,极化弛豫是吸收微波的主要原因。根据纳米Si/C/N复相粉体与石蜡复合体的实测介电参数,设计出多组在8GHz~18GHz范围内微波反射系数R≤-8dB的吸波涂层结构。
先生之风,山高水长------纪念陈希孺院士逝世一周年
,白志
应用概率统计 , 2006,
Abstract:
纳米雷达波吸收剂的研究和发展
,周万城
材料工程 , 1998,
Abstract: 纳米雷达波吸收剂是一类非常有发展前途的新型吸收剂,综述了纳米雷达吸收剂的研究和发展情况,以及纳米雷达波吸收剂的吸波机理,详细介绍了纳米金属、合金、氧化物、碳化硅、石墨、Si/C/N、Si/C/N/O、导电聚合物、金属膜/绝缘介质膜、金属膜/绝缘介质球、氮化物等多种纳米雷达波吸收剂,并指出了纳米雷达吸收剂的发展趋势。
中国劳动力老龄化是否影响全要素生产率?——基于省级面板数据的研究
作  者:,
- , 2016,
Abstract: 采用我国1990-2010年省级面板数据,笔者通过实证研究发现,劳动力年龄结构对全要素生产率的影响表现为倒U形,且40-49岁劳动力对全要素生产率的贡献最大。当前50-59岁劳动力占总劳动力比重较低,劳动力老龄化对全要素生产率的影响尚不显著。但是2020年后特别是2040年,50-59岁劳动力比例保持在较高水平,老龄化对全要素生产率的抑制作用将趋于显著
短暂性脑缺血发作对脑缺血耐受影响的初步研究
The Clinical Study of Transient Ischemic Attack on Cerebral Ischemic Tolerance
 [PDF]

, , 王学敏, 朱静, 田小卫
Asian Case Reports in Vascular Medicine (ACRVM) , 2012, DOI: 10.12677/acrvm.2012.11001
Abstract:
目的:探讨短暂性脑缺血发作(transient ischemic attack, TIA)与脑梗死间的相关性。方法:根据患者脑梗死前是否发生同侧TIA,将所有研究对象分为TIA组和对照组,将2组人群脑梗死体积和临床神经功能缺损程度评分进行比较;同时观察TIA组患者TIA发作持续时间、发作次数等因素对脑梗死体积和临床神经功能缺损的影响。结果:先发TIA患者的脑梗死体积和临床神经功能缺损评分均显著低于对照组(P < 0.05)。TIA持续时间、发作次数、同型半胱氨酸、超敏C反应蛋白等因素均对脑梗死体积和临床神经功能缺损评分产生显著影响。结论:先发TIA有可能对后继脑梗死患者的脑细胞有一定的积极作用,并且脑梗死体积和临床神经功能缺损程度与特定的TIA发作持续时间、发作次数、同型半胱氨酸、超敏C反应蛋白显著相关。
Objective: To explore whether transient ischemic attack (TIA) is significantly associated with subsequent cerebral infarction. Methods: A total of 415 patients were enrolled in this study and were divided into TIA (n = 205) and control group (n = 210), based on presence or absence of TIA before the ischemic cerebral infarction occurrence. The cerebral infarct volume and Neurological deficit scores were compared between the two groups. Furthermore, multiple linear model analysis was conducted to evaluate the impact of TIA on the volume of infarction and Neurological deficit scores in patients who had TIA before. Results: The volume of cerebral infarction and Neurological deficit scores in patients with TIA were significantly lower than those of the control group (P < 0.05). TIA duration, TIA frequency, level of Homocysteine and Hypersensitive C-reactive protein were significantly associated with the volume of cerebral infarction and Neurological deficit scores (P < 0.05). Conclusion: Prior TIA may have a positive impact on the cells of brain. The duration and frequency of TIA and level of Homocysteine and Hypersensitive C-reactive protein are independent risk factors of the volume of cerebral infarction and Neurological deficit scores.
光照强度对微绿球藻生长及有机质积累的影响
Effect of Light Intensity on Growth Rate and Accumulation of Organics of Nannochloropsis oculata Droop
 [PDF]

杜晓凤, 邹宁,,,
Bioprocess (BP) , 2011, DOI: 10.12677/bp.2011.12005
Abstract: 本文以微绿球藻(Nannochloropsis oculata Droop)为材料,在室内研究了光照强度对藻细胞生长及细胞内几种有机物质含量的影响。结果表明,在1000 lx~10,000 lx的光强范围内,比生长速率、可溶性蛋白、类胡萝卜素的含量随光照强度的增加而增加,在5000 lx时达到最高,最高值分别为0.101、3.8%、0.8%,在10,000 lx时反而降低;最高细胞密度随光照强度的增强而增大,10,000 lx时达到最高,为6.52 × 107 mL–1;多糖、总脂含量随光照强度的增加而增加,在2000 lx时达到最高,最高值分别为3.17%、36.95%,在10,000 lx时又降低;叶绿素的含量随光照强度的增强而减小,1000 lx时最高,为0.35%。
Influence of light intensities on growth rate and organics contents of Nannochloropsis oculata was studied. The results showed that the light intensity within 1000 lx and 10,000 lx, the specific growth rate, so-luble protein, and carotenoids contents increased at first and reached the maximum under 5000 lx, then de-creaded under 10,000 lx, the maximums are 0.101, 3.8% and 0.8%. The maximal cell density increased with the increase of light intensity, the maximum is 6.52 × 107 mL–1. Polysaccharide and lipid contents increased and reached the maximum under 2000 lx, then decreased with the increase of light intensity, the maximums are 3.17% and 36.95%. Chlorophyll content decreased with increase of light intensity, the maximum is 0.35%.
轮虫培育池生态系统各有机碳库储量及其日变化
李晓,,振兴,董双
应用生态学报 , 2006,
Abstract: 2001年5~6月对辽宁省盘锦光合水产有限公司的两种模式轮虫培育池有机碳库储量及动态进行了研究.结果表明,静水池溶解有机碳(doc)和颗粒有机碳(poc)库储量平均值分别为5.69±2.90mg·l-1和24.56±2.12mg·l-1;流水池doc和poc分别为9.61±3.17mg·l-1和24.13±2.91mg·l-1.流水池和静水池toc、doc和poc的比例分别为1∶0.75∶0.25和1∶0.82∶0.18.poc含量高的池塘doc含量也较高.流水池的poc、doc周日变动幅度大,静水池昼夜变动幅度小.流水池poc含量白天(5:00~17:00)升高,静水池降低,夜间(15:00~23:00)两池poc含量均降低.从23:00至次日5:00上升,两池分别在17:00和5:00达到高峰.白天(5:00~17:00)流水池doc/poc升高,静水池降低;夜间(17:00~23:00)两池均上升,23:00至次日5:00则呈下降趋势.
385例行穿透性角膜移植术患者的回顾性分析
Retrospective Analysis of 385 Patients Received Penetrating Keratoplasty
 [PDF]

丛林, 桂秋, , 胡丽婷, 徐强, 夏一萍, 曲建秋, 彭旭
Hans Journal of Ophthalmology (HJO) , 2014, DOI: 10.12677/HJO.2014.34006
Abstract:
目的:对2008~2013年间于我院行穿透性角膜移植术患者的流行病学状况进行回顾性分析,汇总患者多方面流行病学特征从而为预防和早期治疗提供指导依据。方法:收集整理我院6年间共计385例(385眼)行穿透性角膜移植术患者的详细病历资料,按照国内外统一标准对其进行分类统计,回顾性总结行穿透性角膜移植术患者的流行病学状况,具体分析其适应症分布、病因分布、年龄分布、职业分布和手术目的分布等情况。结果:6年来,各种原因导致的感染性角膜溃疡为我院行穿透性角膜移植术的主要适应证,占总数的54.5%,其次为圆锥角膜(23.6%)和角膜白斑(10.6%)。其中,角膜真菌性感染占感染性角膜溃疡的80%左右,病毒性角膜溃疡(53.7%)反复发作为角膜白斑致病的主要原因。年龄分布以41~60岁左右的中年患者(47.5%)居多,职业分布以农民(64.2%)、工人(20.3%)为主。患者行穿透性角膜移植术的目的多以治疗性(61.6%)为主。结论:治疗感染性角膜溃疡的早期需及时检测和明确致病病原体,采取有针对性的治疗措施可有效地抑制病原体的增殖入侵,从而降低角膜移植率。
Objective: By analyzing the epidemiological situation of patients who did penetrating corneal trans-plantation in our hospital from 2008 to 2013, we find out the epidemiological characteristics for prevention and early treatment. Methods: We collected the data of 385 patients who accepted pene-trating corneal transplantation in six years. These cases were classified in accordance with the uni-fied domestic and abroad standard, such as indication, etiology, age, vocation and purpose distribu-tion. The epidemiological situation of penetrating corneal transplantation cases were summarized retrospectively. Results: In 6 years, most of the indications of penetrating corneal transplantation cases were infective corneal ulcer caused by various reasons, accounted for 54.5%, followed by ke-ratoconus (23.6%) and keratoleukoma (10.6%). The fungal infection was accounted for about 80% among the infective corneal ulcer. The recurrent occurrence of viral corneal ulcer (53.7%) was a leading cause of keratoleukoma. Age distribution showed that most of the patients were at their middle age from 41 to 60 years old (47.5%). The main components of professional distribution were farmers (64.2%) and workers (20.3%). The main reason of penetrating corneal transplantation cases was for therapeutic purposes (61.6%). Conclusion: Penetrating corneal transplantation is the most classic and effective method to treat corneal diseases of visual impairment. During the treat-ment of infective corneal ulcer, we need to detect and confirm the pathogens timely and to take cor-responding measures to restrain the proliferation and invasion of pathogens. Consequently, we can reduce the rate of penetrating corneal transplantation surgery.
蜂窝系统上行的多业务智能接纳控制方法
董全,李建,
北京邮电大学学报 , 2012, DOI: 10.13190/jbupt.201202.32.dongq
Abstract: 为满足下一代网络接入业务多样化的需求,提出了一种基于蜂窝网上行的多业务智能接纳(ICAC)方法.该方法通过统计语音业务的业务量,对下一时间段进行业务预测并分配相应的接入资源;对于数据业务,运用模糊逻辑对用户分配带宽资源.仿真结果表明,对于动态变化的业务流,该方法可有效降低语音业务掉话率和呼损率,减少数据业务接入的等待时延.
镀Ni-P和Ni-N合金碳纳米管的磁性能及其复合材料的微波吸收性能
,卢振明,沈曾民
复合材料学报 , 2004,
Abstract: 用竖式炉流动法,以二茂铁为催化剂,噻吩为助催化剂,苯为碳源通过催化裂解反应在1100~1200℃制备了直线形碳纳米管,外径为20~50nm,内径10~30nm,长度50~1000μm。用化学镀工艺在碳纳米管表面均匀包覆了Ni-P和Ni-N合金,研究了它们的磁性能及其环氧树脂基复合材料在2~18GHz的微波吸收性能。与纯碳纳米管相比,镀Ni-P合金碳纳米管复合材料的吸收峰向高频移动,镀Ni-P和Ni-N合金碳纳米管经热处理后,复合材料的吸收峰向低频移动。镀Ni-P合金碳纳米管以及镀Ni-P和Ni-N合金经热处理碳纳米管的矫顽力分别为304.34Oe、81.65Oe、183.85Oe。随着矫顽力的增加,在2~18GHz,复合材料的微波吸收峰向高频移动。在复合材料中,碳纳米管以及镀Ni-P和Ni-N合金的碳纳米管作为偶极子吸收微波。
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