HPLC法测定伐地昔布的有关物质

建立高效液相色谱法检测伐地昔布的有关物质.采用α-酸性糖蛋白键合硅胶的手性色谱柱,以乙腈-醋酸铵缓冲液(0.01 mol/L,pH4.0)作为流动相进行梯度洗脱,检测波长215 nm.伐地昔布与5个已知杂质均可达到基线分离,在各自浓度范围内线性关系良好,平均回收率95.13％～99.77％,RSD1.10％～1.77％,检测限0.017 9～0.060 1 μg/mL,定量限0.059 7～0.200 0 μg/mL.方法专属性强,准确度好,灵敏度高,可为伐地昔布的质量控制及后续分离提纯和帕瑞昔布的质量控制提供指导.     

Turbulent boundary layer control with a spanwise array of DBD plasma actuators

The turbulent boundary layer control on NACA 0012 airfoil with Mach number ranging from 0.3 to 0.5 by a spanwise array of dielectric barrier discharge(DBD)plasma actuators by hot-film sensor technology is investigated.Due to temperature change mainly caused through heat produced along with plasma will lead to measurement error of shear stress measured by hot-film sensor,the correction method that takes account of the change measured by another sensor is used and works well.In order to achieve the value of shear stress change,we combine computational fluid dynamics computation with experiment to calibrate the hot-film sensor.To test the stability of the hot-film sensor,seven repeated measurements of shear stress at Ma = 0.3 are conducted and show that confidence interval of hot-film sensor measurement is from-0.18 to 0.18 Pa and the root mean square is 0.11 Pa giving a relative error 0.5％over all Mach numbers in this experiment.The research on the turbulent boundary layer control with DBD plasma actuators demonstrates that the control makes shear stress increase by about 6％over the three Mach numbers,which is thought to be reliable through comparing it with the relative error 0.5％,and the value is hardly affected by burst frequency and excitation voltage.     

提升我国电磁安全能力的战略思考

阐述电磁安全的战略背景,分析电磁兼容到电磁安全的演化过程,剖析"自扰、互扰、敌扰"等现实迫切问题,阐明电磁干扰、电磁兼容等基本概念和相互关系,提出新需求、新技术、新趋势引发电磁兼容与电磁安全的"六大技术挑战",指出只有在认识和思维上系统性地实现"三个转变",才能实现电磁安全整体能力的提升,最后提出"电磁强国"的"五维布局"建议.     

Synergistic effect of bulk phase doping and layered-spinel structure formation on improving electrochemical performance of Li-Rich cathode material

In this study, La was doped into the lithium layer of Li-rich cathode material and formed a layered-spinel hetero-structure. The morphology, crystal structure, element valence and kinetics of lithium ion migration were studied by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The La doped lithium-rich cathode material exhibited similar initial discharge capacity of 262.8 mAh g^?1 at 0.1 C compared with the undoped material, but the discharge capacity retention rate can be obviously improved to 90% after 50 cycles at 1.0 C. Besides that, much better rate capability and Li⁺ diffusion coefficient were observed. The results revealed that La doping not only stabilized the material structure and reduced the Li/Ni mixing degree, but also induced the generation of spinel phase to provide three-dimensional diffusion channels for lithium ion migration. Moreover, the porous structure of the doped samples also contributed to the remarkable excellent electrochemical performance. All of these factors combined to significantly improve the electrochemical performance of the material.     

CaDHN3, a Pepper (Capsicum annuum L.) Dehydrin Gene Enhances the Tolerance against Salt and Drought Stresses by Reducing ROS Accumulation

Dehydrins (DHNs) play an important role in abiotic stress tolerance in a large number of plants, but very little is known about the function of DHNs in pepper plants. Here, we isolated a Y₁SK₂-type DHN gene “CaDHN3” from pepper. To authenticate the function of CaDHN3 in salt and drought stresses, it was overexpressed in Arabidopsis and silenced in pepper through virus-induced gene silencing (VIGS). Sub-cellular localization showed that CaDHN3 was located in the nucleus and cell membrane. It was found that CaDHN3-overexpressed (OE) in Arabidopsis plants showed salt and drought tolerance phenotypic characteristics, i.e., increased the initial rooting length and germination rate, enhanced chlorophyll content, lowered the relative electrolyte leakage (REL) and malondialdehyde (MDA) content than the wild-type (WT) plants. Moreover, a substantial increase in the activities of antioxidant enzymes; including the superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), and lower hydrogen peroxide (H₂O₂) contents and higher O₂^•− contents in the transgenic Arabidopsis plants. Silencing of CaDHN3 in pepper decreased the salt- and drought-stress tolerance, through a higher REL and MDA content, and there was more accumulation of reactive oxygen species (ROS) in the CaDHN3-silenced pepper plants than the control plants. Based on the yeast two-hybrid (Y2H) screening and Bimolecular Fluorescence Complementation (BiFC) results, we found that CaDHN3 interacts with CaHIRD11 protein in the plasma membrane. Correspondingly, the expressions of four osmotic-related genes were significantly up-regulated in the CaDHN3-overexpressed lines. In brief, our results manifested that CaDHN3 may play an important role in regulating the relative osmotic stress responses in plants through the ROS signaling pathway. The results of this study will provide a basis for further analyses of the function of DHN genes in pepper.     

弹性元件参数优化对扑翼机构转速波动影响研究

以特拉华大学机械系统实验室所研制的样机模型进行建模,该模型传动机构采用曲柄摇杆机构.传动机构在运转的过程中,翅翼会在气动力和惯性力作用下产生周期性波动,导致电机转速波动增大,影响机构的平稳运行,产生振动和噪声.在仿真试验中引入弹簧元件,可有效降低电机转速波动,利用正交试验设计方法对影响电机转速波动的影响因素进行极差分析,得出弹簧的连接点位置是主要因素,弹簧的刚度系数是次要因素,弹簧原长影响最小.搭建了物理实验平台,验证了仿真结果和正交试验设计方法的正确性.     

50型螺旋式钢板仓卷边设备理论分析与试验

结合已有卷边设备的生产工艺和特点,研发了国内首台50型螺旋式钢板仓卷边设备,并完成了4次样机调试试验.分析了新型卷边设备关键机构的工作原理,对下轧辊调节机构进行了力学计算分析,完成了卷边孔型设计.利用显示动力学软件数值模拟了5 mm钢板的冷弯成形(卷边)过程,分析了成形过程中的等效应力和等效塑性应变.通过4次样机调试试验,将调试结果与模拟结果对比.结果 表明,折弯5 mm钢板比折弯3 mm的钢板力载荷大很多,有必要研发新型的卷边设备;卷边设备的后3个工位的应力峰值比前3个工位大,其中工位6应力峰值最大;文中的卷边孔型设计合理;卷边过程的模拟结果与试验结果一致.     

石粉和脱硫石膏混合装置的设计与应用

利用双轴搅拌机的工作原理设计的石粉和脱硫石膏混合装置，将石粉和脱硫石膏混合成干湿均匀料加入水泥磨，既利用了石粉、节约了石子，又解决了水泥生产过程中脱硫石膏水分大、不便输送和难稳定入磨的问题，效果显著。     

一种新型的室温快速固化胶黏剂的研制

本文开发了一种新型的方舱夹芯板用室温固化高强度环氧结构胶黏剂,验证了其物化特性、相关力学性能和环境适应性。结果表明此胶黏剂具有优良性能,可以满足方舱用大板胶黏剂的使用需求。     

Recent Advances in Design of Functional Biocompatible Hydrogels for Bone Tissue Engineering

Bone related diseases have caused serious threats to human health owing to their complexity and specificity. Fortunately, owing to the unique 3D network structure with high aqueous content and functional properties, emerging hydrogels are regarded as one of the most promising candidates for bone tissue engineering, such as repairing cartilage injury, skull defect, and arthritis. Herein, various design strategies and synthesis methods (e.g., 3D-printing technology and nanoparticle composite strategy) are introduced to prepare implanted hydrogel scaffolds with tunable mechanical strength, favorable biocompatibility, and excellent bioactivity for applying in bone regeneration. Injectable hydrogels based on biocompatible materials (e.g., collagen, hyaluronic acid, chitosan, polyethylene glycol, etc.) possess many advantages in minimally invasive surgery, including adjustable physicochemical properties, filling irregular shapes of defect sites, and on-demand release drugs or growth factors in response to different stimuli (e.g., pH, temperature, redox, enzyme, light, magnetic, etc.). In addition, drug delivery systems based on micro/nanogels are discussed, and its numerous promising designs used in the application of bone diseases (e.g., rheumatoid arthritis, osteoarthritis, cartilage defect) are also briefed in this review. Particularly, several key factors of hydrogel scaffolds (e.g., mechanical property, pore size, and release behavior of active factors) that can induce bone tissue regeneration are also summarized in this review. It is anticipated that advanced approaches and innovative ideas of bioactive hydrogels will be exploited in the clinical field and increase the life quality of patients with the bone injury.