Regulation and Reconstruction of Cell Phenotype Gradients Along the Tendon-Bone Interface

Tendon–bone interface is prevalent in the human body. It is divided into four zones: tendon (soft tissue), unmineralized fibrocartilage, mineralized fibrocartilage, and bone (hard tissue). Tendon–bone interface is characterized by a cell phenotype gradient that appears in the different zones. The cell phenotype gradients at the tendon–bone interface are orchestrated by specific intracellular molecular mechanisms, extracellular factors, immune signals, and neurovascular factors. These features have inspired scientists to design systems that mimic natural cell phenotype gradients. These biomimetic systems include the construction of cell sheets, regulation of cellular microenvironments, and the design of gradient functional scaffolds. Exploration of methods to mimic cell phenotype gradients is instructional for future clinical applications in reconstituting the tendon–bone interface. The present review elucidates the gradient composition of the tendon–bone interface. The associated regulatory mechanisms and applications are discussed, with the anticipation of creating a mise en scène for future research in interface tissue engineering.     

Cooperative and opportunistic transmission for wireless ad hoc networks

Moving toward 4G, wireless ad hoc networks receive growing interest due to users' provisioning of mobility, usability of services, and seamless communications. In ad hoc networks fading environments provide the opportunity to exploit variations in channel conditions, and transmit to the user with the currently "best" channel. In this article two types of opportunistic transmission, which leverage time diversity and multi-user diversity, respectively, are studied. Considering the co-channel interference and lack of a central controller in ad hoc networks, the "cooperative and opportunistic transmission" concept is promoted. For opportunistic transmission that exploits time diversity, it is observed that the inequality in channel contention due to the hidden terminal phenomenon tends to result in energy inefficiency. Under this design philosophy, we propose a distributed cooperative rate adaptation (CRA) scheme to reduce overall system power consumption. Taking advantage of the time-varying channel among different users/receivers and being aware of the potential contention among neighboring transmissions, we propose a QoS-aware cooperative and opportunistic scheduling (COS) scheme to improve system performance while satisfying QoS requirements of individual flows. Simulation results show that by leveraging node cooperation, our proposed schemes, CRA and COS, achieve higher network throughput and provide better QoS support than existing work     

Fatigue-Resistant Conducting Polymer Hydrogels as Strain Sensor for Underwater Robotics

Conducting polymer hydrogels are widely used as strain sensors in light of their distinct skin-like softness, strain sensitivity, and environmental adaptiveness in the fields of wearable devices, soft robots, and human-machine interface. However, the mechanical and electrical properties of existing conducting polymer hydrogels, especially fatigue-resistance and sensing robustness during long-term application, are unsatisfactory, which severely hamper their practical utilities. Herein, a strategy to fabricate conducting polymer hydrogels with anisotropic structures and mechanics is presented through a combined freeze-casting and salting-out process. The as-fabricated conducting polymer hydrogels exhibit high fatigue threshold (>300 J m⁻²), low Young's modulus (≈100 kPa), as well as long-term strain sensing robustness (over 10 000 cycles). Such superior performance enables their application as strain sensors to monitor the real-time movement of underwater robotics. The design and fabrication strategy for conducting polymer hydrogels reported in this study may open up an enticing avenue for functional soft materials in soft electronics and robotics.     

基于B/S架构的产品质量监督检验综合服务平台的探讨与开发

本文探讨在新的网络环境下,为适应企业、公众、政府等方面的新需求,对原有C/S结构下产品质量监督检验平台进行改进与提升,通过B/S架构的平台完整实现内部流程和业务的信息化管理,同时对外拓宽检验信息状态及时通知、查询及企业质量状况查询等内容,以适应于我国电子政务和现代管理发展的趋势,更好的建设服务型质检技术支撑机构。     

Self‐Powered Trajectory,Velocity, and Acceleration Tracking of a Moving Object/Body using a Triboelectric Sensor

Motion tracking is of great importance in a wide range of fields such as automation, robotics, security, sports and entertainment. Here, a self‐powered, single‐electrode‐based triboelectric sensor (TES) is reported to accurately detect the movement of a moving object/body in two dimensions. Based on the coupling of triboelectric effect and electrostatic induction, the movement of an object on the top surface of a polytetrafluoroethylene (PTFE) layer induces changes in the electrical potential of the patterned aluminum electrodes underneath. From the measurements of the output performance (open‐circuit voltage and short‐circuit current), the motion information about the object, such as trajectory, velocity, and acceleration is derived in conformity with the preset values. Moreover, the TES can detect motions of more than one objects moving at the same time. In addition, applications of the TES are demonstrated by using LED illuminations as real‐time indicators to visualize the movement of a sliding object and the walking steps of a person.     

静电除尘用脉冲电源拓扑研究

对一种静电除尘用脉冲电源高压拓扑进行了研究,通过模态分析谐振状态及谐振后的震荡转态,研究耦合电感、耦合系数及谐振腔电阻对静电除尘器电源输出电压的影响,优化设计耦合电感及耦合系数。通过理论分析,推导出各部分激励对负载的传递函数表达式,并绘制三维变参数曲面图进行系统参数分析,最后搭建1.5 k V的脉冲电源系统,验证静电除尘器电源拓扑的工作原理及理论分析设计的正确性。     

CMMB地面覆盖方案探讨

介绍了中国移动多媒体广播CMMB基本情况,对CMMB地面覆盖进行了初步探讨,对CMMB单频网的组建方式、建网要求等作了简要论述。     

GaAs基GaSb体材料及InAs/GaSb超晶格材料的MBE生长

采用分子束外延方法在GaAs(100)衬底上生长GaSb体材料,以此GaSb为缓冲层生长了不同InAs厚度的InAs/GaSb超晶格,其10K光致发光谱峰值波长在2.0～2.6 μm.高分辨透射电子显微镜观察证实超晶格界面清晰,周期完整.     

2D Nitrogen‐Doped Carbon Nanotubes/Graphene Hybrid as Bifunctional Oxygen Electrocatalyst for Long‐Life Rechargeable Zn–Air Batteries

The rational construction of efficient bifunctional oxygen electrocatalysts is of immense significance yet challenging for rechargeable metal–air batteries. Herein, this work reports a metal–organic framework derived 2D nitrogen‐doped carbon nanotubes/graphene hybrid as the efficient bifunctional oxygen electrocatalyst for rechargeable zinc–air batteries. The as‐obtained hybrid exhibits excellent catalytic activity and durability for the oxygen electrochemical reactions due to the synergistic effect by the hierarchical structure and heteroatom doping. The assembled rechargeable zinc–air battery achieves a high power density of 253 mW cm^?2 and specific capacity of 801 mAh g_Zn^?1 with excellent cycle stability of over 3000 h at 5 mA cm^?2. Moreover, the flexible solid‐state rechargeable zinc–air batteries assembled by this hybrid oxygen electrocatalyst exhibits a high discharge power density of 223 mW cm^?2, which can power 45 light‐emitting diodes and charge a cellphone. This work provides valuable insights in designing efficient bifunctional oxygen electrocatalysts for long‐life metal–air batteries and related energy conversion technologies.     

大视场星敏感器光学系统畸变校正方法

针对大视场星敏感器光学系统畸变较大,严重影响角距测量精度的问题,采用多项式拟合算法,对研制的星敏感器进行了畸变校正,校正后的平均角度测量误差小于1″。