2D Group IVB Transition Metal Dichalcogenides

Semiconductor technology is currently impaired by the surface dangling bond of materials, which introduces scattering and interface traps. 2D materials, especially transition metal dichalcogenides (TMDs) with different main groups, have settled this issue by utilizing unique atomically smooth surfaces and van der Waals (vdW) structures. Over the past few decades, many processes for exploring new materials, manipulating physical properties, and synthesizing single crystals have been developed. Among these 2D materials, group IVB TMDs are distinguished for their splendid physical properties, including ultrahigh mobility, charge density wave, superconducting transitions, etc. Here, the recent advances in group IVB TMDs are reviewed, which offer easy access to next generation nano-, opto-, thermal-electronic, energy storage and conversion applications. Both the advantages and challenges of these studies are summarized to further clarify existing problems.     

基于AT89C52单片机的烟雾报警器设计

介绍了一种基于AT89C52单片机和MQ-2型半导体电阻式烟雾传感器的烟雾报警器设计。该烟雾报警器具有声光报警、浓度显示以及与上位机串口通信等功能。其结构简单,价格低廉,性能稳定,具有较好的实用价值。     

Charge-Driven Self-Assembled Microspheres Hydrogel Scaffolds for Combined Drug Delivery and Photothermal Therapy of Diabetic Wounds

The treatment of diabetic wound remains a big clinical challenge. Hydrogel that can provide physical barrier and humidity displays amazing potentials for managing the diabetic wounds healing. Herein, a new charge-driven self-assembled microsphere hydrogel scaffold (SMHS) is reported based on an electric charge interaction, by combining use of black phosphorus (BP)-contained chitosan methacryloyl (CS) microspheres with positive charge and basic fibroblast growth factor-contained hyaluronic acid methacryloyl (HA) microspheres with negative charge. The weak charge attraction among microspheres gives the SMHS the injectable characteristic. Due to the existence of BP, near-infrared (NIR) irradiation has obvious effects on the degradation and drug release behaviors of SMHS. Significantly, SMHS that combines the short-term physical (photothermal) intervention and long-term chemical (drug release) intervention may be promising in spatio-temporal regulation of regenerative microenvironment. SMHS with NIR irradiation (SMHS+NIR) can promote cell proliferation, cell migration, angiogenesis and macrophage polarization. Moreover, in diabetic rat skin wounds, SMHS+NIR significantly accelerates the wound healing process by simultaneously inhibiting the inflammatory response, promoting angiogenesis and tissues remodeling. The outcome of this research not only provides a biomaterial for diabetic wounds healing, but also demonstrates a new strategy for designing novel hydrogel-based biomaterials which have the free editing and combination functions.     

一种新型压阻值理论计算方法

A novel algorithmic method, based on the different stress distribution on the surface of thin film in an SOI microstructure, is put forward to calculate the value of the silicon piezoresistance on the sensitive film. In the proposed method, we take the Ritz method as an initial theoretical model to calculate the rate of piezoresistance ΔR/R through an integral （the closed area Ω where the surface piezoresistance of the film lies as the integral area and the product of stress σ and piezoresistive coefficient π as the integral object） and compare the theoretical values with the experimental results. Compared with the traditional method, this novel calculation method is more accurate when applied to calculating the value of the silicon piezoresistance on the sensitive film of an SOI pieoresistive pressure sensor.     

探讨中国电信运营商的海外拓展之路

如何实现"走出去"是中国电信运营商普遍关注的问题.本文分析了中国电信运营业国际化的背景,总结了国内外电信运营商全球拓展的经验和教训,并以此为基础就中国电信运营商的海外拓展战略、模式,海外市场选择以及资本运作等关键问题进行了探讨,以寻求适合中国电信运营商海外拓展的健康之路.     

On the Deembedding Issue of CMOS Multigigahertz Measurements

The purpose of this paper is to address the issues of deembedding multigigahertz CMOS measurements by extensively comparing six popular methods and by proposing a new method based on two-port measurements. The comparison aims to evaluate the maximum applicable frequency of equivalent-circuit methods (open-short, three step, ...) and the effect of the source dangling leg of MOSFETs on the cascade methods (two line and thru). Fifty dummy structures and 12 MOSFETs were fabricated using standard 0.18-mum CMOS technology. It was found that, at low frequencies (<6 GHz), all method results were comparable. The open-short method performed well over the entire frequency range (0.1-40 GHz) studied. The newly developed method, called the thru-short method, uses only two dummy structures, a thru and a short, to completely deembed the parasitics from probe pads, interconnects, and the semiconducting substrate. The measurements validated the thru-short algorithm and showed its usefulness for multigigahertz on-wafer CMOS measurements.     

中国通信转型战略管理模型构建与实证

随着我国社会经济体制变革的不断深入,通信企业在快速发展的同时,实现战略转型管理是提高企业综合的重要途径。本文论述了中国通信浙江省通信产业服务有限公司宁波市分公司转型的五个发展阶段,分析了通信企业转型战略管理模型构建遇到的难题,阐述了目前企业管理模式中存在的问题,针对问题进行研究与分析,提出在新的社会形势下,通信企业应该要如何实现转型,构建新型的管理模式,使得企业能更好地应对激烈的市场竞争。希望通过本文分析能实现通信企业的转型,并且顺利实现现代化管理。     

一种内容中心网络传输内容冗余的消除方法

为了减少互联网中传输数据包的大量冗余信息,减少网络流量,提高网络带宽利用效率,研究利用内容中心网络特殊的通信方式及路由器的内容缓存能力,提出一种内容中心网络(CCN)中网络级的传输内容冗余消除方法,在CCN中实现网络级的传输内容冗余消除。并通过仿真分析,验证了该方法可以有效地减少CCN网络中的流量。     

SER‐Based Relay Selection for Two‐Way Relaying with Physical Layer Network Coding

To enhance the symbol error rate (SER) performance of the two‐way relay channels with physical layer network coding, this letter proposes a relay selection scheme, in which the relay with the maximal minimum distance between different points in its constellation among all relays is selected to assist two‐way transmissions. We give the closed‐form expression of minimum distance for binary phase‐shift keying and quadrature phase‐shift keying. Additionally, we design a low‐complexity method for higher‐order modulations based on look‐up tables. Simulation results show that the proposed scheme improves the SER performance for two‐way relay networks.     

一种基于显著不相关检验的快速分形图像编码方法

针对分形编码计算量过大的缺点,本文提出一种基于显著不相关检验的分形编码方法。对于文中的测试图像（Lenn256×256×8ppb和Boat256×256×8ppb）,其编码速度比基于子块分类的分形编码方法快2～15倍,而解码图像质量（PSNR）没有明显下降,压缩比还有一定的提高。