Silver Schottky diodes on Kelvin,AES and LEED characterized (100)surfaces of GaAs cleaned by ion bombardment

Schottky contacts were produced by silver evaporation on GaAs surfaces cleaned by ion bombardment. The samples work function were measured before and after metal deposition with the Kelvin method in an experimental set up which allowed a topographical study and direct comparison between n and p types. Surfaces were controlled by AES and LEED. It was found that the Fermi level of all the surfaces was pinned in the midgap range and so there was, on both n and p types, an important surface barrier qV_s whose value did not strongly depend on the surface preparations we used. The diodes we obtained also presented an important barrier φ_B for both n and p types. So it was deduced that diode barriers corresponded to those that were created by surface states and that metal deposition did not noticeably modify these states. On the other hand, surface preparations played an important role in the electrical performances of the diodes. It was deduced then that ion bombardment deteriorated the first atomic layers of the semiconductor.     

Absorption of NOx in packed column (II)

An absorption efficiency of packed column removing nitrogen oxides with water and NaOH solution under atmospheric pressure was studied. The efficiency and the acidity produced by absorption of NO, were measured in a packed column. The model developed that was based on the mass-transfer information for packed column and absorption mechanism accompanying the chemical reaction was compared with experimental results. Predictions using the model presented by the previous paper (part 1) was shown well to agree with from the experimental results (part II). The efficiency of NO_x, absorption is largely dependent on the height of packing material and the partial pressure of NO_x in the feed gas. The efficiency of NO_x absorption decreases with the increase of the acidity produced by recycling of water as a scrubber liquid. For the recycle mode with an aqueous NaOH solution as a scrubber liquid, NO_x absorption efficiency is shown to be constant until all of the C_OH- in the scrubber liquid are converted into C_H+.     

自动考勤系统的设计与实现

自动考勤系统从用户和管理员两方面功能入手,对系统总体框架和基本功能分别进行了设计。员工的功能包括查询和输入考勤状态,管理员的主要功能有考勤记录管理、员工加班操作、加班记录管理、记录查询、信息记录打印和系统的登陆、退出等,可以分别对员工的考勤状态进行查询、修改和删除,统计并可以显示当天所有员工的考勤状态[3]。在对每个功能进行设计时,从处理过程和存储等方面进行了详细的论述。系统以jdk1.5为开发环境,用Java语言进行编程[5],该系统操作简单,保证其稳定运行。     

稳健的单站无源目标跟踪算法研究

无源定位与跟踪系统中面临着可观测性弱、初始误差大的问题,因此寻找一种稳健快速的跟踪算法显得尤为关键。本文在对现有跟踪算法进行分析和比较的基础上,提出一种IUKF(Improved Unscented Kalman Filter)算法,它通过对传统的UKF算法进行修正,改善了对状态滤波值和协方差的估计。与现有算法(如EKF,UKF)相比,新算法不仅适应能力强、稳定性高,而且收敛速度快、跟踪误差小,是一种稳健的无源目标跟踪算法,数值仿真和试验结果表明了算法的正确性和有效性。     

Congestion‐aware multiaccess edge computing collaboration model for 5G

In 5G cloud computing, the most notable and considered design issues are the energy efficiency and delay. The majority of the recent studies were dedicated to optimizing the delay issue by leveraging the edge computing concept, while other studies directed its efforts towards realizing a green cloud by minimizing the energy consumption in the cloud. Active queue management‐based green cloud model (AGCM) as one of the recent green cloud models reduced the delay and energy consumption while maintaining a reliable throughput. Multiaccess edge computing (MEC) was established as a model for the edge computing concept and achieved remarkable enhancement to the delay issue. In this paper, we present a handoff scenario between the two cloud models, AGCM and MEC, to acquire the potential gain of such collaboration and investigate its impact on the cloud fundamental constraints; energy consumption, delay, and throughput. We examined our proposed model with simulation showing great enhancement for the delay, energy consumption, and throughput over either model when employed separately.     

Influence of transient flow and solder bump resistance on underfill process

The underfill flow process is one of the important steps in Microsystems technology. One of the best known examples of such a process is with the flip-chip packaging technology which has great impact on the reliability of electronic devices. For optimization of the design and process parameters or real-time feedback control, it is necessary to have a dynamic model of the process that is computationally efficient yet reasonably accurate. The development of such a model involves identifying any factors that can be neglected with negligible loss of accuracy. In this paper, we present a study of flow transient behavior and flow resistance due to the presence of an array of solder bumps in the gap. We conclude (1) that the assumption of steady flow in the modeling of the flow behavior of fluids in the flip-chip packaging technology is reasonable, and (2) the solder bump resistance to the flow can not be neglected when the clearance between any two solder bumps is less than 60-70 μm. We subsequently present a new model, which extends the one proposed by Han and Wang in 1997 by considering the solder bump resistance to the flow.     

Wearable,Healable, and Adhesive Epidermal Sensors Assembled from Mussel‐Inspired Conductive Hybrid Hydrogel Framework

Healable, adhesive, wearable, and soft human‐motion sensors for ultrasensitive human–machine interaction and healthcare monitoring are successfully assembled from conductive and human‐friendly hybrid hydrogels with reliable self‐healing capability and robust self‐adhesiveness. The conductive, healable, and self‐adhesive hybrid network hydrogels are prepared from the delicate conformal coating of conductive functionalized single‐wall carbon nanotube (FSWCNT) networks by dynamic supramolecular cross‐linking among FSWCNT, biocompatible polyvinyl alcohol, and polydopamine. They exhibit fast self‐healing ability (within 2 s), high self‐healing efficiency (99%), and robust adhesiveness, and can be assembled as healable, adhesive, and soft human‐motion sensors with tunable conducting channels of pores for ions and framework for electrons for real time and accurate detection of both large‐scale and tiny human activities (including bending and relaxing of fingers, walking, chewing, and pulse). Furthermore, the soft human‐motion sensors can be enabled to wirelessly monitor the human activities by coupling to a wireless transmitter. Additionally, the in vitro cytotoxicity results suggest that the hydrogels show no cytotoxicity and can facilitate cell attachment and proliferation. Thus, the healable, adhesive, wearable, and soft human‐motion sensors have promising potential in various wearable, wireless, and soft electronics for human–machine interfaces, human activity monitoring, personal healthcare diagnosis, and therapy.     

Fluorinated Polyimide as a Novel High‐Voltage Binder for High‐Capacity Cathode of Lithium‐Ion Batteries

An increase in the energy density of lithium‐ion batteries has long been a competitive advantage for advanced wireless devices and long‐driving electric vehicles. Li‐rich layered oxide, xLi₂MnO₃?(1?x)LiMn_1?y?zNi_yCo_zO₂, is a promising high‐capacity cathode material for high‐energy batteries, whose capacity increases by increasing charge voltage to above 4.6 V versus Li. Li‐rich layered oxide cathode however suffers from a rapid capacity fade during the high‐voltage cycling because of instable cathode–electrolyte interface, and the occurrence of metal dissolution, particle cracking, and structural degradation, particularly, at elevated temperatures. Herein, this study reports the development of fluorinated polyimide as a novel high‐voltage binder, which mitigates the cathode degradation problems through superior binding ability to conventional polyvinylidenefluoride binder and the formation of robust surface structure at the cathode. A full‐cell consisting of fluorinated polyimide binder‐assisted Li‐rich layered oxide cathode and conventional electrolyte without any electrolyte additive exhibits significantly improved capacity retention to 89% at the 100th cycle and discharge capacity to 223–198 mA h g^?1 even under the harsh condition of 55 °C and high charge voltage of 4.7 V, in contrast to a rapid performance fade of the cathode coated with polyvinylidenefluoride binder.     

Over 16.7% Efficiency Organic‐Silicon Heterojunction Solar Cells with Solution‐Processed Dopant‐Free Contacts for Both Polarities

Realization of synchronous improvement in optical management and electrical engineering is necessary to achieve high‐performance photovoltaic device. However, inherent challenges are faced in organic‐silicon heterojunction solar cells (HSCs) due to the poor contact property of polymer on structured silicon surface. Herein, a remarkable efficiency boost from 12.6% to over 16.7% in poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate)/n‐silicon (PEDOT:PSS/n‐Si) HSCs by independent optimization of hole‐/electron‐selective contacts only relying on solution‐based processes is realized. A bilayer PEDOT:PSS film with different functionalizations is utilized to synchronously realize conformal contact and effective carrier collection on textured Si surface, making the photogenerated carriers be well separated at heterojunction interface. Meanwhile, fullerene derivative is used as electron‐transporting layer at the rear n‐Si/Al interface to reduce the contact barrier. The study of carriers' transport and independent optimization on separately contacted layers may lead to an effective and simplified path to fabricate high‐performance organic‐silicon heterojunction devices.     

增强现实技术原理及其在电视中的应用

详细介绍了增强现实技术的原理以及实现增强现实系统的关键技术,包括三维空间注册技术、人机交互技术和3D展现技术。然后对当前增强现实技术在电视领域的应用进行阐述,并分析了电视应用实现中的难点问题。最后,对增强现实技术的进一步研究进行了展望。