M2M大型装备远程监控

M2M产生于20世纪90年代中后期,以监控设备和资产为目标而产生.随着社会的不断发展和技术的不断进步,M2M不再是简单的数据在机器间的传输,更重要的是,它是机器与机器间智能化、交互式的通信.利用M2M网络实现大型装备的远程实时监控.对于企业和国家都越发重要.     

一种大管径煤气管道带压堵漏的应用

文章介绍了针对DN2200煤气总管泄漏,一种新型大管径煤气管道带压堵漏的性能和工作原理.     

浅议原平市糯玉米的发展

糯玉米营养价值高,经济效益好,原平市发展糯玉米产业前景广阔.通过加强政策引导,统一规划布局,完善产销体系,采用先进的栽培技术发展无公害、绿色的糯玉米,提高糯玉米及系列产品的精加工,根据市场需求,生产出能满足各种消费层次的系列产品,实现优质糯玉米产品的多层次增值,以生产促基地建设,推进农业产业化的发展.     

低空数码摄影测量的应用探讨

介绍了利用低空数码航测法生产3D产品的技术流程,以河南省新密市测区为例,从低空航测必备条件、技术参数等方面探讨了低空数码摄影测量生产3D产品的组织实施,并指出了目前航测法存在的不足之处。     

Assignment of the μ4-O5 atom in catalytic center for water oxidation in photosystem II

The detailed structure of catalytic center of water oxidation, Mn4Ca-cluster, in photosystem ⅡI (PSII) has been reported recently. However, due to the radiation damage induced by X-ray and the complexity of the Mn4Ca-cluster, the assignment of the μ4-O5 atom coordinated by three Mn and one Ca2+ ions is still lack of essential evidences. In this article, we synthesized one Mn complex containing two μ4-O atoms. It is found that the lengths of all μ4-O-Mn bonds in this Mn complex are in the range of 1.89-2.10 , which are significantly shorter than 2.40-2.61 distance of μ4-O5-Mn bonds in Mn4Ca-cluster observed in the crystal structure of PSII. In addition, DFT calculations have been carried out on the Mn4Ca-cluster. It is found that the O atom of μ4-O or μ4-OH always trends to deviate from the center position of four metal ions, resulting in unequal bond lengths of four μ4-4-M (M=Mn or Ca), which is obviously different with larger and nearly equal distances between μ4-O and four metal ions observed in the crystal structure. Based on these results, we suggest that the μ4-atom in Mn4Ca-cluster of PSII is unlikely to be a μ4-O, μ4-OH or μ4-OH2 , and its assignment is still an open question.     

Effect of KNbO3 content on the crystal structure and electrical properties of (1 − x)PbZr0.54Ti0.46O3-xKNbO3 piezoelectric ceramics

(1 ? x)PbZr_0.54Ti_0.46O₃-xKNbO₃ (0 ≤ x ≤ 25mol%) (abbreviated as PZT-xKN) piezoelectric ceramics were successfully fabricated by a traditional sintering technique at 1225°C for 30 min. The influence of KNbO₃ content on the crystal structure and electrical properties of the PZT-xKN piezoelectric ceramics was studied. Samples with 0 ≤ x ≤ 0.20 show a pure perovskite structure, indicating that all KNbO₃ diffused into the crystal lattice of PZT to form a single solid solution in this compositional range. A second Pb₃Nb₄O₁₃ phase is observed in the PZT-0.25KN sample, showing that the maximum solid solubility of KNbO₃ in PZT matrix ceramic is less than 25mol%. Compared with pure PZT piezoelectric ceramics, samples containing KNbO₃ have smaller crystal grains. PZT-0.15KN exhibits excellent piezoelectric properties with d ₃₃ = 209 pC/N.     

师生谈心高效之浅见

在平时的教学工作中,师生交流与沟通只要能重视方式方法,就能增进师生间相互理解、支持与配合,建立浓厚的师生感情,产生凝聚力、向心力,有利于良好学风的形成,促进学生身心健康发展.那么,教师应如何与学生谈心才能更高效呢.笔者对此进行了论述.     

Plasmonic biosensors and nanoprobes based on gold nanoshells

Gold nanoshells (GNSs), consisting of a dielectric core coated with gold, have gained extensive attention as they show readily tunable optical properties and good biocompatibility. As highly sensitive and label-free optical biosensors with wide applications, GNSs have been investigated in many fields including drug delivery, immunoassay, cancer treatment, biological sensing and imaging. Taking advantage of the adjustability of the local surface plasmon resonance (LSPR) and the sensitivity of the surfaceenhanced Raman scattering (SERS) signal of GNSs, we have developed diverse applications including plasmonic biosensors and nanoprobes based on GNSs. In this review we introduce plasmonic and electromagnetic properties and fabrication methods of GNSs. We describe research progress in recent years, and highlight several applications of GNSs developed by our group. Finally we provide a brief assessment of future development of GNSs as plasmonic materials that can be integrated with complementary analytical techniques.     

单-6-叠氮-β-环糊精与苯乙炔的点击化反应

利用CuI/NBS这种新型催化体系来促进单-6-叠氮-β-环糊精与苯乙炔之间的偶联反应,通过这个多组分反应可以高效地以炔和叠氮为原料一锅法制备5-碘代-1,4-取代-1,2,3-三氮唑类化合物.