摘要：With the expansion of a city,the urban green space is occupied and the urban heat island effect is *** the roof surfaces of urban buildings is an effective way to increase the area of urban green space and improve the urban ecological *** provide effective data support for urban green space planning,this paper used high-resolution images to(1)obtain accurate building spots on the map of the study area through deep learning assisted manual correction;and(2)establish an evaluation index system of roof greening including the characteristics of the roof itself,the natural environment and the human society *** weight values of attributes not related to the roof itself were calculated by Analytic Hierarchy Process(AHP).The suitable green roof locations were evaluated by spatial join,weighted superposition and other spatial analysis *** the areas within the Chengdu city’s third ring road as the study area,the results show that an accurate building pattern obtained by deep learning greatly improves the efficiency of the *** roof surfaces unsuitable for greening can be effectively classified by the method of feature extraction,with an accuracy of 86.58%.The roofs suitable for greening account for 48.08%,among which,the high-suitability roofs,medium-suitability roofs and low-suitability roofs represent 45.32%,38.95%and 15.73%.The high-suitability green buildings are mainly distributed in the first ring district and the western area outside the first ring district in *** paper is useful for solving the current problem of the more saturated high-density urban area and allowing the expansion of the urban ecological environment.

摘要：学生评教是高校普遍实行的一项管理制度,评教结果的有效性,即评教的质量受到教师、学生、教学管理者的高度关注。该文利用语义分析技术对学生留言进行情感挖掘,建立基于知网的情感词库,并设置词的极性权重;以3GWS工具进行分词与词性标注;对留言的情感褒贬程度进行计算,形成教师的评价摘要。以烟台大学评教数据为实验数据,验证该方法科学、有效。

摘要：基于正弦脉宽调制技术具有直流电压利用率高、输出电流谐波含量少等优点,研究设计了一种全数字SPWM三相逆变器系统。该系统具有高效可靠的功率管驱动电路、高精度的电气量采集电路及高开关频率的三相逆变器主电路,由STM32作为控制系统主控芯片,逆变器控制算法采用双闭环SPWM控制,设计了一个小功率三相逆变系统,并通过实验进行了验证。实验结果表明,该系统三相输出波形畸变率小于0.5%,动态性能好,能实现高精度的恒压输出控制。

摘要：中国的药物分子设计研究始于20世纪70年代末,兴于21世纪初,经过几代人的努力,整体已处于国际领先水平.在计算机辅助药物设计方法和技术的指导下,我国许多药物已经上市或进入临床研究.本文回顾了中国药物分子设计领域的发展进程,以初创、成长、发展和壮大4个阶段简述我国改革开放40年来在该领域所取得的主要成就.

摘要：以崇阳县较大面积集中连片的毛竹林分为研究对象,对42个标准地数据进行了统计分析。以坡向(x_1)、坡位(x_2)、坡度(x_3)、腐殖质层厚度(x_4)、土层厚度(x_5)及母岩类型(x_6)为自变量,以毛竹平均胸径(y)为因变量,对其进行逐步回归分析,确定影响毛竹生长的主导因子,并以此作为依据进行立地类型划分。结果表明,影响崇阳毛竹胸径大小的主导因子是土层厚度(x_5)、母岩类型(x_6)及坡位(x_2),回归方程为:y=6.332+0.358 x_2+0.060 x_5-0.662 x_6。通过因子分析,将6个立地因子划分为2个主成分,其中第一个主成分映了土壤因子方面的信息,第二个主成分反映了地形因子方面的信息。应用主成分聚类分析方法可将进行崇阳县毛竹立地划分为4种类型:页岩中下坡厚土层立地类型、页岩上坡中土层立地类型、石灰岩中下坡中土层立地类型及石灰岩上坡薄土层立地类型。应该分别不同立地类型,确定毛竹林经营的主要方向,并制定相应的生产描述措施以促进毛竹林高产、稳产与高效。