24 research outputs found

    Research and utilization of polarization effects in GaN based LED

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    本论文结合科研项目,针对III-V族氮化物中存在的极化电场,自洽求解薛定谔方程和泊松方程。提出了利用及消除极化电场的方法,为GaN基LED工艺优化提供理论基础,并通过实验降低p型GaN欧姆接触电阻,提高LED的内量子效率。所做的研究工作主要分三个部分:计算机模拟极化电场影响下,量子阱和超晶格中的一维薛定谔方程和柏松方程的自洽求解。计算得到电子和空穴的各级本征函数和本征值,该方法可以推广到求解任意势中的定态薛定谔方程。根据极化电场使能带发生摆动,提高Mg杂质的离化率,增大空穴浓度,提出利用InGaN/AlGaN超晶格做GaN基LED的p型接触顶帽层,降低欧姆接触电阻并充当电流扩展层作用。计算比较...Based on the polarization effect in III-V nitride, we solve self-consistently the Schrödinger and Poisson equation. Both utilization and elimination of the polarization field are proposed. Experimentally, specific contact resistance to p-GaN is reduced and internal quantum efficiency of LED is improved. The main work we have done are listed as follows, Solving self-consistently the Schrö...学位:理学硕士院系专业:物理与机电工程学院物理学系_凝聚态物理学号:1982006115180

    深度卷积神经网络应用于人脸特征点检测研究

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    为解决在复杂环境下,如姿势不同、光照条件以及遮挡等因素导致传统人脸特征点检测算法的精度大幅度下降的问题,在特征点检测理论知识以及研究现状的基础上,针对传统卷积神经网络模型在处理人脸特征点检测问题时的不足之处,提出基于小滤波器的深卷积神经网络。算法引入小滤波器思想和以拓展\"网络深度\"优先的深层卷积神经网络模型,针对人脸特征点检测重新设计训练,提高了算法的有效性与适用性。通过将算法应用于ALFW和AFW人脸数据集上预测5点人脸特征点问题,并与其他多个经典算法进行对比分析,结果表明:基于小滤波器的深卷积神经网络在预测人脸5点特征点问题上有更好的准确性和鲁棒性。福建省中青年教师教育科研项目(No.JZ160238);;国家自然科学基金(No.61502402);;福建省自然科学基金(No.2015J05129

    Reduce Ohmic Contact Resistance to p-GaN Using InGaN/AlGaN Superlattice

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    提出用P-IngAn/AlgAn超晶格作为P-gAn的接触层来获得低阻欧姆接触。通过一维薛定谔方程和泊松方程的自洽求解,得到了在极化效应影响下的IngAn/AlgAn,IngAn/gAn和gAn/AlgAn三种超晶格中Mg杂质离化率的空间分布。计算发现IngAn/AlgAn超晶格具有最高的Mg杂质离化率及最佳的空穴局域作用。最后,利用P-IngAn/AlgAn超晶格实验上实现了比接触电阻率为7.27x10-5Ω.CM2的良好欧姆接触。In order to achieve a smaller Ohmic contact resistance,p-InGaN/AlGaN superlattice was proposed to be used as the cap-layer of p-GaN.By making use the self consistent Poisson-Schrodinger calculations,obtained were the distributions of the ionization rate of Mg dopant in InGaN/AlGaN,InGaN/GaN and GaN/AlGaN superlattices when taking into account of the effect of polarization.It was found that the InGaN/AlGaN superlattice cap-layer had the largest ionization rate of Mg and the best confinement of the holes.Finally,the specific contact resistance of 7.27×10-5 Ω·cm2 was realized.国家自然科学基金项目(60276029);国家“863”计划项目(2004AA311020;2006AA032409);福建省科技项目(2006H0092;A0210006;2005HZ1018

    Investigation on the iodine status among the population in rural and urban areas of Xiamen in 2013

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    目的了解碘盐新标准实施后农村和城市人群的碘营养现况,为有效落实科学补碘防控策略提供依据。方法在农村和城市调查点各抽取1个镇的1个村,在每个村采集自来水厂出厂水和末梢水各2份;抽取30户以上居民,采集各户家庭食用盐,用3日称量法测算各户居民人均食盐摄入量;抽取18-45岁成人50名以上,采集尿样。在抽中的镇随机选择8-10岁儿童(男女各半)、孕妇和哺乳期妇女各50名以上,采集尿样。测定盐碘、尿碘和水碘含量。结果农村和城市自来水末梢水水碘含量均值分别为4.5μg/L和6.0μg/L;居民人均每日食用盐摄入量中位数分别为7.0和5.6g;8~10岁儿童尿碘中位数分别为152.0和181.2μg/L;哺乳妇尿碘中位数分别为108.3和107.7μg/L;18-45岁成人尿碘中位数分别为121.1和147.4μg/L;孕妇尿碘中位数分别为116.0和112.2μg/L,尿碘含量低于150μg/L的比例分别达67.9%和64%;除农村人均每日食用盐摄入量高于城市,农村18-45岁成人尿碘水平低于城市外,其他指标农村和城市间差异无显著性。结论厦门市仍是缺碘地区,在现有碘盐标准下,8-10岁儿童、18-45岁成人、哺乳期妇女的碘营养处于适宜水平,但孕妇的碘营养不足,要开展针对孕期人群的碘营养监测和指导,杜绝碘缺乏所造成的危害。Objective To gain knowledge of the iodine status among the population in rural and urban areas after the implement of new standard for edible salt and to provide scientific evidence for the initiative of the iodine supplement strategy. Method 1 village / community was selected randomly from rural and urban area as research site respectively. 2 samples of treated water and tap water were collected respectively in both sites, 30 + houses were enrolled randomly and edible salt samples were collected. 3days weighed record was employed to estimate average salt daily intake. Urine sample was collected from 50 + adults aged from 18 to 45. Identical sample was also collected from 50 + children aged from 8 to 10( same amount of subjects in both genders),pregnant women, and lactating women respectively. Iodine level of water, salt, and urine was determined by laboratory assay.Results The iodine concentration of tap water in rural and urban areas was 4. 5 μg / L and 6. 0 μg / L,respectively. The median of average iodine intake in rural and urban areas was 7. 0 g and 5. 6 g, respectively. The median in urine iodine was 152. 0 μg / L and 181. 2 μg / L,respectively. This measurement in lactating women was 108. 3 μg / L and 107. 7 μg / L,respectively. And it was121. 1 μg / L and 147. 4 μg / L in adults aged 18 to 45, respectively. As for the pregnant women, the iodine level reached 116. 0μg /L and 112. 2 μg /L,respectively. The proportion of subjects has urine iodine level less than 150 μg /L reached 67. 9 % and 64 %, respectively. The average salt intake in rural area was higher than urban significantly, and the urine iodine level in adults aged 18 to 45 from rural area was significantly lower than urban. No significance was found in other comparison. Conclusion Through our investigation,Xiamen is still an iodine deficiency area. Under the implement of new edible salt standard, the iodine status in children aged 8 to 10, adults aged 18 to 45 and lactating women was adequate, however, we found that pregnant women enrolled in our study have iodine deficiency in some degrees. Therefore the iodine surveillance and dietary guidance should be performed among pregnant women to eliminate the harm caused by iodine deficiency

    福建鲍产业发展形势分析

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    鲍,素有\"软黄金\"的美誉。自上世纪90年代开始,福建引入皱纹盘鲍与日本盘鲍的杂交鲍并逐渐扩大养殖规模。笔者归纳了福建省鲍的养殖分布及生产情况,结合鲍的消费结构及产业支撑现状发现鲍产业发展过程中的育苗场规划,养殖管理,种质退化,安全用药等方面存在问题,对此提出推进科学养殖,增强环保意识;加强管理制度建设,实现质量监管;加强种质管理,选育新品种;加强技术体系建设;提升产业融合度等建议

    沿海产盐区与非产盐区8~10岁儿童碘营养与智力水平分析

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    目的了解和比较沿海产盐区和非产盐区8~10岁儿童碘营养状况与智力水平,为采取针对性防治措施提供依据。方法选择产盐区翔安区和非产盐区集美区的小学为调查点,8~10岁儿童为调查对象,调查其家中碘盐食用情况、尿碘含量、甲状腺肿大情况和智商水平。结果产盐区和非产盐区儿童合格碘盐食用率分别为81.5%和98.6%;甲状腺肿大率分别为3.0%和0.7%,尿碘中位数分别为202.8μg/L和238.4μg/L,<50μg/L的比例分别为3.5%和1.0%。产盐区8~10岁儿童智商均明显低于非产盐区儿童;产盐区8岁儿童智商明显高于9岁和10岁儿童;非产盐区8岁儿童智商明显高于9岁和10岁儿童,9岁儿童智商明显高于10岁儿童。结论补碘能提高儿童智商,降低智力损害。要坚持食用碘盐,开展对孕妇、哺乳妇的碘营养监测

    沿海产盐区与非产盐区妊娠期妇女碘营养状况及甲状腺功能水平分析

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    目的了解福建沿海产盐区与非产盐区妊娠期妇女碘营养状况及其甲状腺功能水平,为防治碘缺乏病提供科学依据。方法选择产盐区翔安区和非产盐区集美区为调查点,每个点随机抽取60名以上妊娠期妇女作为调查对象,采集孕妇的家中盐样、尿样及血样,分别测定盐碘、尿碘及血清甲状腺激素。结果产盐区与非产盐区孕妇合格碘盐食用率分别为81.69%和100.00%;产盐区与非产盐区孕妇尿碘的中位数分别为120.55μg/L和153.35μg/L,尿碘孕中期>孕晚期;产盐区与非产盐区孕妇的甲状腺过氧化物酶抗体(thyroid peroxidase antibody,TPOAb),抗甲状腺球蛋白抗体(antithyroid glubulin antibody,TgAb),总三碘甲状腺原氨酸(total-triiodothyronine,TT3),总甲状腺素(total thyroxine,TT4),游离三碘甲状腺原氨酸(free triiodothyronine,FT3),游离甲状腺素(free thyroxine,FT4),促甲状腺激素(thyroid stimulating hormone,TSH),甲状腺球蛋白(tryroglobulin,Tg)中位数均在正常范围,产盐区与非产盐区孕妇的FT3、FT4、TSH之间差异均有统计学意义,产盐区孕妇的FT3、FT4均低于非产盐区,而产盐区孕妇的TSH则高于非产盐区。结论孕妇是易缺碘人群,产盐区孕妇相对非产盐区碘缺乏更为严重。应对孕妇开展常规碘营养和甲状腺功能监测,进一步做好碘营养知识的宣传教育工作,控制碘缺乏病的发生

    Discovery and structural characterization of a therapeutic antibody against coxsackievirus A10

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    9月20日,《科学》子刊《科学•进展》(Science Advances)刊出了我校夏宁邵教授团队发表的题为“Discovery and structural characterization of a therapeutic antibody against coxsackievirus A10”的研究论文。该研究首次发现手足口病重要病原体柯萨奇病毒A组10型(CVA10)不同类型病毒颗粒共有的优势中和表位,揭示了病毒颗粒及其与优势中和抗体复合物的精确三维结构,阐明了中和抗体的功能与作用机制,为新型疫苗和治疗药物的研制提供了重要的理论基础。 该研究首次揭示并描绘了CVA10的病毒颗粒及其优势中和表位的精确特征,发现了具有良好应用潜能的治疗性中和抗体,为新型疫苗和特异性治疗药物的研究提供了关键基础。 我校夏宁邵教授、程通副教授和美国加州大学洛杉矶分校纳米系统研究所Z. Hong Zhou(周正洪)教授、美国加州大学圣地亚哥分校颜晓东博士为该论文的共同通讯作者。我校博士生朱瑞、徐龙发博士后、郑清炳工程师、李少伟教授和美国加州大学洛杉矶分校崔彦祥博士后为该论文共同第一作者。【Abstract】Coxsackievirus A10 (CVA10) recently emerged as a major pathogen of hand, foot, and mouth disease and herpangina in children worldwide, and lack of a vaccine or a cure against CVA10 infections has made therapeutic antibody identification a public health priority. By targeting a local isolate, CVA10-FJ-01, we obtained a potent antibody, 2G8, against all three capsid forms of CVA10. We show that 2G8 exhibited both 100% preventive and 100% therapeutic efficacy against CVA10 infection in mice. Comparisons of the near-atomic cryo–electron microscopy structures of the three forms of CVA10 capsid and their complexes with 2G8 Fab reveal that a single Fab binds a border region across the three capsid proteins (VP1 to VP3) and explain 2G8’s remarkable cross-reactivities against all three capsid forms. The atomic structures of this first neutralizing antibody of CVA10 should inform strategies for designing vaccines and therapeutics against CVA10 infections.This work was supported by grants from the National Science and Technology Major Projects for Major New Drugs Innovation and Development (2018ZX09711003-005-003), the National Science and Technology Major Project of Infectious Diseases (2017ZX10304402-002-003), the National Natural Science Foundation of China (31670933 and 81801646), and the National Institutes of Health (R37-GM33050, GM071940, DE025567, and AI094386). We acknowledge the use of instruments at the Electron Imaging Center for Nanomachines supported by the University of California, Los Angeles and by instrumentation grants from NIH (1S10RR23057 and 1U24GM116792) and NSF (DBI-1338135 and DMR-1548924). 该研究获得了国家自然科学基金、新药创制国家科技重大专项、传染病防治国家科技重大专项和美国国立卫生研究院基金的资助

    沿海产盐区与非产盐区18~45岁人群碘营养状况及甲状腺功能水平研究

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    目的掌握厦门市沿海产盐区与非产盐区居民盐碘、18~45岁人群碘营养和甲状腺功能水平状况,为采取针对性的防治措施提供依据。方法选择沿海产盐区翔安区和非产盐区集美区为调查点,调查居民合格碘盐食用率、18~45岁育龄期妇女和男性尿碘水平、甲状腺激素水平和海带、紫菜的摄入习惯。结果产盐区和非产盐区盐碘中位数均为27.21 mg/kg,合格碘盐食用率分别为95.33%和96.33%;18~45岁男性尿碘中位数分别为206.55μg/L和232.95μg/L,尿碘<100μg/L的比例分别为20.97%和10%;18~45岁育龄期妇女尿碘中位数分别为176.95μg/L和227.70μg/L,尿碘<100μg/L的比例分别为21.67%和25%;产盐区和非产盐区18~45岁男性和育龄期妇女的甲状腺激素TSH、Tg、FT3、FT4、TPOAb、TT3、TT4中位数均在正常值范围内;产盐区18~45岁男性的甲状腺功能亢进阳性率为3.4%、育龄期妇女的甲状腺功能减退和亚临床甲状腺减退症的阳性率均为1.67%,而非产盐区均为0。产盐区和非产盐区18~45岁男性和育龄期妇女中均有一定比例易患甲状腺免疫性疾病的人群。每月食用海带、紫菜的次数≥4次、1~3次和<1次的人尿碘组间比较无统计学差异。结论产盐区和非产盐区18~45岁男性和育龄期妇女碘营养总体处于适宜状态,应坚持食盐加碘措施,对育龄期妇女在婚前体检时开展常规碘营养水平和甲状腺功能检测

    Near-atomic cryo-electron microscopy structures of varicella-zoster virus capsids

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    VZV是一种广泛存在并且具有高度传染性的人类α-疱疹病毒。初次感染VZV可导致水痘,人群普遍易感(感染率约为61%~100%)。该病毒可在背根神经节潜伏感染,持续终生。夏宁邵教授团队长期开展VZV相关基础与新型疫苗研究,通过系统和精细探索建立了高效的VZV规模化培养和病毒颗粒纯化技术体系,成功获得高质量的VZV颗粒样品。首次揭示了疱疹病毒α家族的水痘-带状疱疹病毒(VZV)不同类型核衣壳的近原子分辨率结构,阐明了VZV核衣壳不同组成蛋白的相互作用网络与衣壳装配机制,可为进一步开展新型载体疫苗设计及抗病毒药物等研究提供重要支持。 我校博士后王玮、高级工程师郑清炳、博士生潘德全和俞海副教授为该论文共同第一作者,我校夏宁邵教授、程通副教授、李少伟教授以及美国罗格斯大学朱桦(Hua Zhu)教授、加利福尼亚大学洛杉矶分校周正洪(Z. Hong Zhou)教授为该论文的共同通讯作者。【Abstract】Varicella-zoster virus (VZV) is a medically important human herpesvirus that causes chickenpox and shingles, but its cell-associated nature has hindered structure studies. Here we report the cryo-electron microscopy structures of purified VZV A-capsid and C-capsid, as well as of the DNA-containing capsid inside the virion. Atomic models derived from these structures show that, despite enclosing a genome that is substantially smaller than those of other human herpesviruses, VZV has a similarly sized capsid, consisting of 955 major capsid protein (MCP), 900 small capsid protein (SCP), 640 triplex dimer (Tri2) and 320 triplex monomer (Tri1) subunits. The VZV capsid has high thermal stability, although with relatively fewer intra- and inter-capsid protein interactions and less stably associated tegument proteins compared with other human herpesviruses. Analysis with antibodies targeting the N and C termini of the VZV SCP indicates that the hexon-capping SCP—the largest among human herpesviruses—uses its N-terminal half to bridge hexon MCP subunits and possesses a C-terminal flexible half emanating from the inner rim of the upper hexon channel into the tegument layer. Correlation of these structural features and functional observations provide insights into VZV assembly and pathogenesis and should help efforts to engineer gene delivery and anticancer vectors based on the currently available VZV vaccine.This research was supported by grants from the National Science and Technology Major Projects for Major New Drugs Innovation and Development (no. 2018ZX09711003-005-003), the National Science and Technology Major Project of Infectious Diseases (no. 2017ZX10304402), the National Natural Science Foundation of China (no. 81871648, 81601762), the Research Unit of Frontier Technology of Structural Vaccinology of Chinese Academy of Medical Sciences (no. 2019RU022) and the US National Institutes of Health (DE025567/028583). 该研究获得了国家自然科学基金、新药创制国家科技重大专项和传染病防治国家科技重大专项等资助
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