摘要：According to the theory of DBR, with the P-type DBR as an example, the electrical characteristics and optical reflection of the DBR are analyzed by studying the energy band structure with various graded region widths and doping densities. The width and doping density of graded region are decided through a comparative study. The P-type DBR of 980 nm VCSELs is designed with Al0.9Ga0.1As and Al0.1Ga0.9As selected as the high and low refractive index material for the DBR. The 980 nm bottom VCSELs, which consists of 30 pairs P-type DBR and 28 pairs N-type DBR, are then fabricated. In P-type DBR, the width of graded region is 0.02 μm and the uniformity doping concentration is 2.5×10^18cm^-3. Its reflectivity is 99.9%. In N-type DBR, the width of graded region is also 0.02 μm and the uniformity doping concen- tration is 2×10^18cm^-3. Its reflectivity is 99.3%. The I-V curve shows that the series resistance of the device is about 0.05Ω. According to the theory of DBR, with the P-type DBR as an example, the electrical characteristics and optical reflection of the DBR are analyzed by studying the energy band structure with various graded region widths and doping densities. The width and doping density of graded region are decided through a comparative study. The P-type DBR of 980 nm VCSELs is designed, with Al0.9Ga0.1As and Al0.1Ga0.9As selected as the high and low refractive index material for the DBR. The 980 nm bottom VCSELs, which consist of 30 pairs P-type DBR and 28 pairs N-type DBR, are then fabricated. In P-type DBR, the width of graded region is 0.02μm and the uniformity doping concentration is 2.5×10^18cm^-3. Its reflectivity is 99.9%. In N-type DBR, the width of graded region is also 0.02 μm and the uniformity doping concentration is 2×10^18cm^-3. Its refiectivity is 99.3%. The I-V curve shows that the series resistance of the device is about 0.05Ω.

摘要：对掺塑化剂,粉煤灰掺量达80%的烧结砖的制备工艺进行了研究。结果表明,外掺4%塑化剂D的混合料,在8kN压力下成型,采用自然干燥24h,升温至50℃恒温2h,升温至80℃再恒温2h的干燥制度及在1040℃下保温时间2h的烧成制度,获得了密度为1430kg/m3,吸水率27.86%,抗压强度25.4MPa的烧结砖试样。

摘要：对电网安全风险管理控制系统(SRMS)中风险评估功能的实现进行了详细介绍。建立了越限驱动型风险和事件驱动型风险相结合的指标体系,阐述了风险评估方法的流程,提出了风险指标体系在时间维度和空间维度的应用策略。文中最后给出了SRMS在湖南电网的应用算例。

摘要：现阶段,国内制种玉米生产中的去雄环节以人工作业为主,机械化去雄机具短缺,严重制约了玉米种业的发展。针对这一问题,设计了一种柔性圆盘抽取式制种玉米去雄机,以自走式高地隙底盘为搭载平台,采用光电传感器进行雄穗高度信号采集,通过四连杆机构调节抽取部件位置,随着柔性圆盘的转动将玉米雄穗及附带茎叶收拢、夹持、抽取、与植株分离,完成母本雄穗的去除作业。田间试验表明:去雄机以5~8km/h的速度作业时,一次去雄率均值达到86.7%,能够满足机械化去雄作业的要求。

摘要：多自由度姿态调整装置可使其装卡的航空发动机实现三个自由度运动,可以用作航空发动机装配平台。设计研制的调姿装置主要由调姿机构、控制系统等组成。其中调姿机构包含垂直升降、俯仰旋转和轴心回转三个机构;控制系统采用可编程控制器为信号处理单元,以按钮、接近开关、倾角传感器等电气元件的实时信号为输入,输出控制信号至交流伺服电机,通过调姿机构的运动组合完成航空发动机姿态的变换。利用模拟样件替代航空发动机进行试验,经空载、额定载荷、两倍额定载荷的试验检测。结果表明:调姿装置达到了设计要求。

摘要：阐述了夹持输送技术与装置在蔬菜收获机械中的重要性,对夹持输送装置的典型结构、蔬菜受力、运动和驱动系统等进行详细分析。介绍了夹持输送技术与装置在典型胡萝卜收获机和甘蓝收获机中的应用实例,探讨蔬菜夹持输送技术与装置的发展趋势。该研究可为国内蔬菜收获机械的设计、研发提供借鉴和参考。