The Injury and Cumulative Effects on Human Skin by UV Exposure from Artificial Fluorescence Emission

The injury and cumulative effects of UV emission from fluorescence lamp were studied. UV intensity from fluorescence lamp was measured, and human skin samples (hips, 10 volunteers) were exposed to low‐dose UV irradiation (three times per week for 13 consecutive weeks). Three groups were examined: control group without UV radiation; low‐dose group with a cumulative dose of 50 J cm^?2 which was equivalent to irradiation of the face during indoor work for 1.5 years; and high‐dose group with 1000 J cm^?2 cumulative dose equivalent to irradiation of the face during outdoor activities for 1 year. Specific indicators were measured before and after UVA irradiation. The findings showed that extending the low‐dose UVA exposure decreased the skin moisture content and increased the transepidermal water loss as well as induced skin color changes (decreased L* value, increased M index). Furthermore, irradiated skin showed an increased thickness of cuticle and epidermis, skin edema, light color and unclear staining collagen fibers in the dermis, and elastic fiber fragmentation. In addition, MMP‐1, p53 and SIRT1 expression was also increased. Long‐term exposure of low‐dose UVA radiation enhanced skin photoaging. The safety of the fluorescent lamp needs our attention.     

新的基于变色龙的车载通信安全与隐私保护

在车载自组网（VANET）中许多服务和应用需要保护数据通信的安全,为提高驾驶的安全性和舒适性,一些与交通状况有关的信息就要被周期性地广播并分享给司机,如果用户的身份和信息没有隐私和安全的保证,攻击者就会通过收集和分析交通信息追踪他们感兴趣的车辆,因此,匿名消息身份验证是VANET中不可或缺的要求。另一方面,当车辆参与纠纷事件时,证书颁发机构能够恢复车辆的真实身份。为解决车载通信这一问题,郭等人在传统方案的基础上提出一种基于椭圆曲线的变色龙散列的隐私保护验证协议。虽然此方案较之前方案具有车辆身份可追踪性和高效率性,但分析表明此方案不满足匿名性。对郭等人的方案进行安全性分析并在此基础上做出改进。     

互联网视听节目监管系统建设的思索

针对目前各互联网视听节目监管系统存在的问题以及缺乏全局的、系统化的解决方案的现状,提出构建互联网视听节目统一的监管平台,实现多个监管系统的共享共管,实现对海量视听节目数据快速分析和处理,准确掌握各类音视频节目传播的数量、动态、范围和影响等情况,综合提升舆情分析能力,提高监管效率.本文提出网络视听节目监管系统建设的基本思路,就系统建设中需要注意的几个技术环节进行了分析和探讨.     

Ag2S/Al2O3纳米复合物的水热合成及表征

采用水热技术结合煅烧的方法,成功制备了Ag2S/Al2O3纳米复合物。 通过SEM、EDX、XRD等测试技术对产品进行了表征,证明得到的产品是Ag2S/Al2O3纳米复合物;无孔Al2O3和多孔Al2O3作反应模板得到的复合物的形态和分布不同。     

Total synthesis of (-)-cocaine and (-)-ferruginine

Total synthesis of tropane alkaloids (-)-cocaine and (-)-ferruginine were accomplished in nine steps each and in 55% and 46% overall yields, respectively, starting from the known Betti base derivative (+)-(7aR,10R,12S)-10-(1H-benzotriazol-1-yl)-7a,8,9,10-tetrahydro-12-phenyl-12H-naphtho[1,2-e]pyrrolo[2,1-b][1,3]oxazine. In this novel route, RCM reaction and 1,3-dipolar cycloaddition were employed as key steps for the enantioselective construction of tropane skeleton and the regioselective introduction of 3-bromo-2-isoxazoline ring as masked cis-2,3-disubstituents. To obtain the desired precursor (2S,5R)-2-allyl-5-vinylpyrrolidine for RCM reaction, we developed a general and practical method for the preparation of enantiopure cis-2,5-disubstituted pyrrolidines bearing alkene- and/or alkyne-containing substituents. We also offered two highly efficient pathways for the conversion of the 3-bromo-2-isoxazoline ring into the desired cis-2,3-disubstituted groups in (-)-cocaine and (-)-ferruginine.     

光传飞行控制交叉通道数据链路接口技术研究

交叉通道数据链路是实现三余度飞控计算机之间信息交换的枢纽,以往开发的三余度光传操纵系统大都采用了串口(RS232)协议来实现,其传输速率较低,达不到现代飞控计算机之间数据传输的高要求。为此,设计了一套以PCI总线控制器PLX9054和FPGA为核心的双向高速数据光纤传输接口卡,设计了该数据传输卡的基本结构和单元组成;详细阐述了PCI总线接口软硬件设计方法、时序及注意事项,并深入分析了FPGA的功能逻辑模块和光电转换模块的实现方案;最后开发了基于DriverStudio的设备驱动程序,并进行了系统测试。结果表明本接口卡可以满足飞控计算机之间余度数据交换的要求。     

一类两个边界带特征参数的不连续四阶微分算子的自共轭性

本文研究了一类具有特殊转移条件且两个边界条件中带有特征参数的四阶微分算子的自共轭性问题.建立了一个与其相关的新的空间H,将上述问题的研究转化为对此空间中一个线性算子A的研究.     

应用于DC/DC变换器的模拟伪三型补偿结构

介绍了一种采用模拟伪三型的补偿电路,该补偿电路可应用于DC/DC变换器中。通过在PWM比较器前把一个产生低频极点的全差分电路和一个产生低频零点的电路相加,得到两个低频零点和一个低频极点,进而得到快速的负载响应速度。在标准CMOS工艺下仿真了一个应用了伪三型补偿结构的DC/DC变换器,结果表明,在400 mA的负载电流阶跃时,负载调整率和线性调整率均小于2%。     

基于二分校准的混合型数字脉宽调制器

提出了一种基于混合型数字脉宽调制器(HDPWM)的带延迟线二分法校准机制的新电路结构,能有效地提高DPWM的线性度。详细介绍了混合型DPWM的工作原理,阐述了基于二分法机制的自校准电路的整体结构。分析了该结构的后仿真结果,并与带延迟锁相环(DLL)结构的DPWM的后仿真结果相比较。在32 MHz的时钟下,该电路成功实现了开关频率为2 MHz的数字DC-DC变换器中的9-bit DPWM。该电路基于0.13μm 1.2V CMOS工艺实现,最大差分非线性(DNL)仅为0.136 LSB,积分非线性(INL)为0.15 LSB。     

基于趋近律滑模最优控制的无人机撞网回收轨迹控制

针对舰载无人机撞网回收过程的下滑轨迹跟踪控制问题,在设计基于α β滤波器的轨迹控制外回路的基础上,着重设计了趋近律滑模控制与最优控制相结合的姿态控制内回路,提高了系统的稳定性并改善了系统的动态性能。以某小型无人机为例进行了撞网回收全过程三维数值仿真,仿真结果表明,该撞网回收着舰轨迹控制系统能够实现下滑过程飞行姿态及轨迹的精确控制,且能够在舰船甲板运动情况下实现较精确的撞网回收。