Subjects: Digital Publishing >> New Media submitted time 2023-10-08 Cooperative journals: 《中国传媒科技》
Abstract:随着科学技术与信息时代的日趋发展,人们越来越关注调频同步广播技术的发展。本文主要阐述调频同步广播在调频广播中的的基本原理、基本特点、同步网的实现需要注意的问题和调频同步广播未来的发展趋势,为调频同步广播实现区域化覆盖提供参考。
Subjects: Nuclear Science and Technology >> Particle Accelerator submitted time 2023-07-25
Abstract: Based on KONUS dynamics, the beam dynamic design of a compact IH-DTL with built-in permanent magnet quadrupole lens was completed. The DTL is comprised by 37 acceleration gaps and two sets of permanent magnet quadrupole lenses, which can accelerate C6+ ion beam of 20 emA from 0.5 MeV/u to 4 MeV/u. To control the transverse and longitudinal emittance growth of the low-energy heavy ion beams, the gap voltage, injection phase, magnet parameters, and energy and phase settings of the 0-degree reference particles have been optimized so that the transverse normalized RMS acceptance of the IH-DTL reaches 0.37π mm·mrad, and the transmission efficiency is above 95%.
Subjects: Statistics >> Social Statistics submitted time 2023-06-15 Cooperative journals: 《中国科学院院刊》
Abstract:党的二十大报告指出,教育、科技、人才是全面建设社会主义现代化国家的基础性、战略性支撑。实现高水平科技自立自强关键靠人才,制度创新要聚焦大胆选拔和放手使用优秀青年人才,支持青年人才挑大梁、当主角。文章聚焦新时代创新人才的责任与使命,从青年科研人员通过自我修炼力争成为新时代所需的创新人才的路径,以及所在单位为其打造更好的成长环境两个角度给出了建议。
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract: A novel chromium-free titanate- zirconate conversion coating on 2024 aluminum alloy was prepared, the corrosion resistance of the coatings was evaluated by means of potentiodynamic measurement, NSS test and AC impedance spectra. The morphology and composition of the coatings were characterized by means of SEM with EDS. The results showed that the titanate – zirconate conversion coating is made up of micro particles and shows a smooth flat surface with a few defects. After NSS test for 168 h, only a little corrosion products can be observed on the surface of the titanate- zirconate conversion coating on 2024 aluminum alloy, implying that the conversion coating possesses passivation ability to a certain extent. Therefore, the prepared chromium-free titanate-zirconate conversion coating can provide excellent corrosion protection for 2024 aluminum alloy efficiently.
Subjects: Medicine, Pharmacy >> Clinical Medicine submitted time 2022-07-26 Cooperative journals: 《中国全科医学》
Abstract: Alport syndrome (AS) is one of the important causes of chronic kidney disease and end-stage renal disease. It is the second most common inherited kidney disease after autosomal dominant polycystic kidney disease. Autosomal dominant inheritance is a very rare mode of inheritance in AS. It has been reported that patients with autosomal dominant Alport syndrome (ADAS) progress to end-stage renal disease at a later age. This article summarizes the clinical and pathological features, as well as genetic mutations of a novel COL4A4 gene mutation c.3506-3528del (p.G1169Efs*13) in an ADAS family. One family member developed end-stage renal disease at the age of 31.
Subjects: Geosciences >> Hydrology submitted time 2022-06-07 Cooperative journals: 《干旱区地理》
Abstract:基于20012018年MOD10A2积雪产品和MOD11A2陆地表面温度数据,采用精细分区统计和相关性分析方法,研究了中国天山不同海拔高度上积雪垂直分布特征及其与地表温度(Landsurface temperature,LST)的响应关系。结果表明:中国天山积雪覆盖率(Snow cover percentage,SCP)随海拔的变化呈现春、夏、秋、冬4种不同的季节变化模式。SCP在海拔4200 m以下呈秋冬季增加、春夏季减少态势,在海拔4200 m以上呈秋冬季减少、春夏季增加态势。除冬季外,春、夏、秋3个季节的SCP与LST均具有显著强负相关性。
Subjects: Psychology >> Other Disciplines of Psychology submitted time 2021-10-24
Abstract: In qualitative research, saturation is usually used to assess the adequacy of research data. However, in research practice, there are various forms of saturation, and the relationships between them are complicated and ambiguous. Previous studies lack operational description and practical guidance for the evaluation of saturation and its reports. Considering its importance to qualitative research, this study clarifies the concepts of saturation. As a sign that the sample size of a qualitative study has met the research needs, based on the time sequence of their occurrence during the research process, saturation can be distinguished into four types: data saturation, code or thematic saturation, meaning saturation, and theoretical saturation. Each of them has its specific connotations, evaluation methods and judgment criteria. Some problems are discussed in this study. 1) The sample size to reach saturation should not be set uniformly, and it must be embedded in the specific research process; 2) Due to the logical uncertainty of saturation, a little oversampling would be helpful; 3) As an important index to evaluate the quality of a qualitative research, saturation test cannot be applicable to all forms of qualitative research. "
Subjects: Biology >> Zoology submitted time 2018-12-20 Cooperative journals: 《动物营养学报》
Abstract:本试验旨在研究饲粮添加不同水平的辣木叶对育肥猪生长性能、屠宰性能、抗氧化功能和肉品质的影响。选用体况良好、平均体重为(65.40±1.63) kg的“杜×长×大”三元杂交育肥猪144头,随机分为4个组,每组6个重复,每个重复6头猪。对照组饲喂基础饲粮,试验组分别饲喂在基础饲粮中添加3%、6%和9%辣木叶的试验饲粮。预试期7 d,正试期45 d。结果表明:1)与对照组相比,6%辣木叶组育肥猪的终末体重和平均日增重显著提高(P0.05)。与对照组相比,6%和9%辣木叶组育肥猪的肌肉SOD活性和总抗氧化能力显著提高(P<0.05)。综上所述,饲粮中添加辣木叶可以提高育肥猪的生长性能和抗氧化功能,改善肉品质。本试验条件下,辣木叶适宜添加水平为6%。
Subjects: Biology >> Bioengineering submitted time 2018-05-23 Cooperative journals: 《中国生物工程杂志》
Abstract:专利是技术的有效载体,通过专利态势分析可以在一定程度上有效掌握技术发展脉络及发展趋势。基于专利信息,采用定量数据、定性调研与专家智慧有机结合的方法,从申请趋势、保护市场、领域分布、重要专利权人等多维度分析视角进行农业生物技术领域专利技术态势分析。通过专利态势分析掌握全球农业生物技术专利保护概貌,指出重点方向。在此基础上结合中国农业生物技术领域专利法律状态和专利转让许可状况探讨中国农业生物技术专利保护现状及存在问题,以期支撑中国农业生物技术领域的创新决策。
Subjects: Biology >> Zoology submitted time 2017-10-23 Cooperative journals: 《动物营养学报》
Abstract:本试验旨在研究饲粮中添加酵母寡聚糖(YOS)对高密度养殖条件下蛋鸡生产性能、蛋品质、肠道黏膜形态结构及微生物区系分布、血清生化指标和肠道功能相关基因表达的影响。选取864只12周龄海兰褐蛋鸡,随机分为6个组,每组12个重复,每重复3个笼子,每个笼子3只(低密度)或5只(高密度)。对照组饲喂基础饲粮,试验组饲喂在基础饲粮中分别添加250和500 g/t YOS的饲粮,试验期18周。结果表明:1)饲粮添加YOS能显著提高蛋壳颜色的均匀度(P<0.05)。2)饲粮添加YOS增加了蛋鸡肠道绒毛高度/隐窝深度值(P=0.059),其中250 g/t YOS组显著高于对照组(P<0.05)。3)饲粮添加YOS使得蛋鸡空肠乳酸杆菌数量显著增加(P<0.05),大肠杆菌数量显著减少(P<0.05),其中250 g/t YOS组菌群变化较为明显。4)饲粮添加YOS显著降低了蛋鸡血清中内毒素含量(P<0.05),提高了免疫球蛋白A含量(P=0.090),且250 g/t YOS组较对照组显著提高(P<0.05)。由此可见,饲粮中添加YOS能够改善高密度养殖条件下蛋鸡肠道功能,添加剂量以250 g/t的综合效果较佳。
Subjects: Biology >> Zoology submitted time 2017-10-23 Cooperative journals: 《动物营养学报》
Abstract:本试验旨在研究活性酵母对脂多糖(LPS)应激黄羽肉鸡肠道健康的影响。选取480羽1日龄黄羽肉公鸡,随机分成6个组,分别为抗生素组(基础饲粮+0.025‰抗生素)、抗生素+LPS组(基础饲粮+0.025‰抗生素,注射LPS)、0.05%活性酵母组(基础饲粮+0.05%活性酵母)、0.05%活性酵母+LPS组(基础饲粮+0.05%活性酵母,注射LPS)、0.50%活性酵母组(基础饲粮+0.50%活性酵母)和0.50%活性酵母+LPS组(基础饲粮+0.50%活性酵母,注射LPS),每组8个重复,每个重复10只鸡。试验期56 d。抗生素+LPS组、0.05%活性酵母+LPS组和0.50%活性酵母+LPS组的试验鸡于21、23、25和27日龄按每千克体重肌肉注射1 mg LPS,其余试验鸡肌肉注射等量生理盐水。于21和27日龄注射LPS或生理盐水后2、4、6、8、10、12和24 h测量试验鸡的直肠温度,并检测27和56日龄试验鸡的肠道细胞凋亡指数以及27、35和56日龄试验鸡的肠道食糜微生物数量和肠道形态结构。结果表明:1)与注射生理盐水相比,LPS刺激显著提高了21日龄注射后2 h和27日龄注射后2、4 h黄羽肉鸡的直肠温度(P0.05);饲粮中添加活性酵母与肌肉注射LPS对黄羽肉鸡的直肠温度无显著交互作用(P>0.05)。2)与注射生理盐水相比,LPS应激显著提高了27日龄黄羽肉鸡的十二指肠和回肠细胞凋亡指数(P0.05);饲粮中添加活性酵母与肌肉注射LPS对黄羽肉鸡的肠道细胞凋亡指数无显著交互作用(P>0.05)。3)与抗生素相比,饲粮中添加0.05%和0.50%的活性酵母极显著提高了27、35和56日龄黄羽肉鸡回肠食糜酵母菌数量(P0.05);饲粮中添加活性酵母与肌肉注射LPS对黄羽肉鸡肠道食糜微生物数量无显著交互作用(P>0.05)。4)与抗生素相比,饲粮中添加0.50%活性酵母显著提高了35日龄黄羽肉鸡的空肠绒毛高度(P0.05)。综上所述,LPS能成功诱导黄羽肉鸡的免疫应激反应,饲粮中添加活性酵母能够提高黄羽肉鸡肠道绒毛高度和食糜中酵母菌数量,改善肠道黏膜及菌群结构,但肌肉注射LPS与饲粮中添加活性酵母无显著交互作用。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-08 Cooperative journals: 《腐蚀科学与防护技术》
Abstract:采用钛酸盐,锆酸盐为主盐,开发了一种应用于2024铝合金表面的无铬钛锆转化膜。通过扫描电子显微镜(SEM)、能谱(EDS)、中性盐雾试验、动电位极化曲线和电化学阻抗谱对转化膜的表面形貌、成分及耐蚀性能进行了表征和分析。结果表明:制备的无铬钛锆转化膜由微米级的微小颗粒组成,膜层均匀平整,无明显缺陷;无铬钛锆转化处理后的2024铝合金,经中性盐雾168h,无腐蚀产物产生;钛锆转化膜具有较低的腐蚀电流和一定的钝化能力,可有效的提高铝合金的耐蚀性能。