摘要：Epitaxial growths of the GaAs/AlGaAs-based 940 nm infrared light emitting diodes(LEDs) with dual junctions were carried out by using metalorganic chemical vapor deposition(MOCVD) with different doping concentrations and Al contents in Al_xGa_(1-x)As *** their optoelectric properties show that the optimal design for tunneling region corresponds to P^(++) layer with hole concentration up to 1×10^(20) cm^(-3), N^(++) layer electron concentration up to 5×10^(19) cm^(-3) and constituent Al_(0.2)Ga_(0.8)As in the tunneling junction *** optimized dual-junction LED has a forward bias of 2.93 V at an injection current of 50 mA, and its output power is 24.5 mW, which is 104% larger than that of the single junction(12 mW).Furthermore, the optimized device keeps the same spectral characteristics without introducing excessive voltage droop.

摘要：目的 开发一个基于大规模视觉语言模型的黑色素瘤诊断框架,并探讨该框架用于黑色素瘤诊断的可行性和准确性。方法 采用公开数据集Derm7pt,其数据集划分为训练集(346例),验证集(161例)和测试集(320例)。提出了一个基于大规模视觉语言模型的黑色素瘤诊断框架,该诊断框架包括两个文本分支和一个视觉分支。在文本分支中,一个分支处理固定的临床提示;另一个分支则处理可学习的提示。这种设计旨在通过固定的临床提示引导和优化可学习提示的效果。视觉分支处理皮肤镜图像,通过微调图像编码来增强对黑色素瘤特征的识别能力。结果 在Derm7pt数据集上,我们的方法在性能上优于现有其他方法。其接收者操作特征曲线下面积(AUC),准确率和F1-分数分别为87.35%,84.17%和84.01%。结论 通过适当的微调策略,基于大规模视觉语言预训练模型的方法能够有效地适应黑色素瘤的诊断任务。这种方法可以作为医生的有力辅助工具,帮助他们做出更加准确的诊断决策。

摘要：Urban stormwater runoff nearly discharges directly into bodies of water through gray infrastructure in China, such as sewers, impermeable ditches, and pump stations. As urban flooding, water shortage, and other environment problems become serious, integrated water environment management is becoming increasingly complex and challenging. At more than 200 ha, the Oriental Sun City community is a large retirement community located in the eastern side of Beijing. During the beginning of its construction, the project faced a series of serious water environment crises such as eutrophication, flood risk, water shortage, and high maintenance costs. To address these issues, an integral storrnwater management master plan was developed based on the concept of low impact development （LID）. A large number of LID and green stormwater infrastructure （GSI） approaches were designed and applied in the community to replace traditional stormwater drainage systems completely. These approaches mainly included bioretention （which captured nearly 85th percentile volume of the annual runoff in the site, nearly 5.4 x 10^5 m3 annually）, swales （which functioned as a substitute for traditional stormwater pipes）, waterscapes, and stormwater wetlands. Finally, a stormwater system plan was proposed by integrating with the gray water system, landscape planning, an architectural master plan, and related consultations that supported the entire construction period. After more than 10 years of planning, designing, construction, and operation, Oriental Sun City has become one of the earliest modem large-scale LID communities in China. Moreover, the project not only addressed the crisis efficiently and effectively, but also yielded economic and ecological benefits.

摘要：The superconducting cyclotron SC200 is intended to generate a 200 MeV, 400 nA proton beam for future particle therapy. The internal hot-cathode-type Penning ionization gauge (PIG) ion source for the SC200 is designed for the generation of hydrogen ions. A brief description of the design of ion source and test bench, which are used in SC200, is given in this paper. The ion source has been verified on the test bench, and the results indicated that the designed ion source meets the expected requirements. The lifetime of the filament exceeded 100 h in the test. In addition, the extraction voltage and the gas flow that influence the extracted ion current intensity have been tested in the experiment.

摘要：河南艺术中心是一座特大型综合性文化艺术建筑,属一类高层公共建筑。舞台的消防设施必须完备,才能在一定时间内阻挡火势向观众厅蔓延,赢得疏散和扑救时间。主舞台雨淋系统的分区平行于主幕布,任一点出现火情,都将启动包括此点所在区和相邻两区的雨淋阀,形成3个区的覆盖保护。台口设置机械防火幕及防护冷却水幕系统。观众厅楼座和吊顶内设置自动喷水灭火系统。在保证消防安全的前提下,也保障了观众厅的声学光学效果。应用三维管道设计软件,对泵房等进行有限空间内管道的有序协调,有效利用空间,为建筑结构设计提供最优条件。最后总结了施工中出现的问题及解决方法。

摘要：为解决马尔科夫链和传统遗传算法设计汽车运行工况时效率低、质量差的问题,提出用于设计汽车运行工况的马氏链非等长交叉进化方法.设计子代满足马尔科夫链转移关系的非等长交叉算子,解除等位等长交叉段的限制,使遗传算法更好地适用于汽车运行工况的设计.根据试验数据,应用马氏链非等长交叉进化方法构建非等长初始种群,使用满意准则模型和指数加权平均数设定目标函数,设计三参数汽车运行工况.随机生成3种不同长度的三参数高速公路代表性工况.分析结果表明,期望运行工况与原始数据库特征参数的相对偏差均在设定范围内,速度和加速联合分布相关系数均高于90%,生成工况具有代表性.相比于马尔科夫链和传统遗传算法相结合的设计方法,马氏链非等长交叉进化方法的平均运行工况生成效率提高了66%,运行工况质量更优.

摘要：The denitrifier method is widely used as a novel pretreatment method for the determination of nitrogen and oxygen isotope ratios as it can provide quantitative and high-sensitivity measurements. Nevertheless, the method is limited by relatively low measurement accuracy for δ18 O. In this study, we analyzed the factors influencing the accuracy of δ18 O determination, and then systematically investigated the effects of dissolved oxygen concentrations and nitrate sample sizes on estimates of the δ15 N and δ18 O of nitrate reference materials. The δ18 O contraction ratio was used to represent the relationship between the measured difference and true difference between two reference materials. We obtained the following main results:(1) a gas-liquid ratio of 3:10(v/v) in ordinary triangular flasks and a shaking speed of 120 r/min produced an optimal range(1.9 to 2.6 mg/L) in the concentration of dissolved oxygen for accurately determining δ18 O, and(2) the δ18 O contraction ratio decreased as nitrate sample size decreased within a certain range(1.0 to 0.1 μmol). Our results suggested that δ18 O contraction is influenced mainly by dissolved oxygen concentrations in pure culture, and provided a model for improving the accuracy of oxygen isotope analysis.

摘要：2018年10月27日至28日,由中国高教学会影视教育专业委员会、西南大学新闻传媒学院、《电影艺术》杂志社、《艺术百家》杂志社、《艺术评论》杂志社联合主办的中国影视艺术高峰论坛暨中国高教影视教育委员会第二十届年会在西南大学举行。学会自创办以来,历经20年发展壮大,硕果累累、影响深远。本次年会分为主论坛及四个分论坛,来自国内国际六十余所高校及研究机构荟萃重庆,共同探讨中国影视教育的热点问题,关注中国影视发展新动态,开拓中国影视教育新界面。会议开幕式由辽宁大学庚钟银教授主持,西南大学党委副书记安春元、中国高等教育学会影视教育专业委员会名誉会长、北京师范大学资深教授黄会林先生在开幕式上致辞。

摘要：针对当前运行工况研究仅选取某些特征参数作为特征、缺乏对工况状态转移特征分析的不足,本文在提取典型工况特征参数的基础上,运用主成分分析和K均值聚类获得行驶特征较明显的3类工况,并分析各类工况状态转移转移矩阵(TPM)的状态、转移概率和特征值。结果表明:各类TPM状态、转移概率的分析与各类典型工况特征参数的分析一致;特征值对高速、混合和城市道路运行工况的工况生成效率存在本质影响,揭示了运行工况设计中构建两参数TPM的合理性。

摘要：介绍了一种基于Czerny-Turner光路结构并采用谐波电机直接驱动光栅的小型快速近红外光谱仪的设计、仿真及初步测试结果.为了减小多次反射及衍射产生的杂散光,运用Cary理论进行光路布局与设计,使用光学软件TracePro进行了仿真,结果显示改进之后的结构有效抑制了系统的杂散光.为了减小体积并提高扫描光谱速度,采用谐波电机直接驱动光栅代替传统的电机传动正弦丝杆再驱动光栅的结构,在近红外光波段对样机性能进行了初步测试,并对葡萄糖水溶液进行了定性测量.初步测试结果显示：波长范围800~1 500 nm,扫描速度达到75 nm/s,光谱分辨率6 nm,波长准确性±0.5 nm,重复性≤1 nm,信噪比为1 000∶3,吸光度重复性≤0.008 AU,基线稳定性0.000 5 A/h,简单葡萄糖水溶液的定性测试结果比较清晰地反映了样品的特性.