高速放大器制程新技术满足新一代低功耗应用需求

新一代无线应用、自动化测试与测量、医疗仪器及图像处理、便携式运算装置等都需要高效能模拟组件，并且对其低功耗的效能要求日益提高。现今厂商运用进阶工艺技术来满足此一要求，例如第三代完全介电隔离式互补双极工艺BiCom—Ⅲ。     

Anisotropic swelling and fracture of silicon nanowires during lithiation

We report direct observation of an unexpected anisotropic swelling of Si nanowires during lithiation against either a solid electrolyte with a lithium counter-electrode or a liquid electrolyte with a LiCoO(2) counter-electrode. Such anisotropic expansion is attributed to the interfacial processes of accommodating large volumetric strains at the lithiation reaction front that depend sensitively on the crystallographic orientation. This anisotropic swelling results in lithiated Si nanowires with a remarkable dumbbell-shaped cross section, which develops due to plastic flow and an ensuing necking instability that is induced by the tensile hoop stress buildup in the lithiated shell. The plasticity-driven morphological instabilities often lead to fracture in lithiated nanowires, now captured in video. These results provide important insight into the battery degradation mechanisms.     

iMAC: improved Medium Access Control for multi‐channel multi‐hop wireless networks

Trends in wireless networks are increasingly pointing towards a future with multi‐hop networks deployed in multi‐channel environments. In this paper, we present the design for iMAC—a protocol targeted at Medium Access Control in such environments. iMAC uses control packets on a common control channel to facilitate a three‐way handshake between the sender and the receiver for every packet transmission. This handshake enables the sender and the receiver to come to a consensus on a channel to use for data transmission and also signals to neighboring nodes about the contention on that channel. iMAC then uses a mechanism similar to 802.11 for data communication. Our evaluation of iMAC shows that it provides significant gains in throughput in comparison with uninformed channel selection, especially when contention for channel bandwidth is neither too low nor too high; intelligent selection of channels by iMAC is necessary to harness available bandwidth resources in the presence of medium levels of contention. Copyright © 2011 John Wiley & Sons, Ltd.     

Scratch Cell Test: A Simple,Cost Effective Screening Tool to Evaluate Self-Healing in Anti-Corrosion Coatings

A quick and simple scratch cell set up to evaluate the self-healing of an hybrid sol-gel (ormosil) coating was fabricated. This methacrylate-based anti-corrosion coating was applied on the aerospace aluminium alloy AA2024-T3, and cured at room temperature. This technique of evaluation requires minimum instrumentation. The inhibitors cerium nitrate, benzotriazole and 8-hydroxy quinoline (8-HQ) were used in the study. The self-healing ability of the inhibitors decreased in the following order: 8-HQ, BTZ and Ce. 8-HQ showed the highest self-healing ability and was comparable to the commercial hexavalent chromium conversion coating—Alodine. Spectroscopic analysis of the electrolyte and EDX of the coatings indicated the movement of the inhibitor from the coating to the site of damage, thereby effecting self-healing. It was observed that an increased inhibitor concentration in the coatings did not accelerate the healing process. Inhibitor release was slower in the coatings doped with inhibitor-loaded nano-containers, when compared to inhibitor-spiked coatings. This property of controlled release is desirable in self-healing coatings. Electro impedance studies further confirmed self-healing efficiency of the coatings. The scratch cell study reported here is the first of its kind with the ormosil under study on AA2024-T3 aluminium alloy. The results are encouraging and warranty a quick and simple qualitative screening of the self-healing potential of the inhibitors with minimum instrumentation.     

Reliability/cost implications of utilizing photovoltaics in small isolated power systems

The rapid growth of renewable energy applications in electric power systems dictates a need to develop comprehensive techniques that can be used to evaluate the economics involved and the reliability of power supply that can be achieved from the utilization of these energy sources. Photovoltaic (PV) arrays have the potential to significantly reduce operating costs in remote small systems which are generally supplied using costly diesel fuel. This paper presents a simulation method that provides objective indicators to help system planners decide on appropriate installation sites, selection of PV arrays or diesel units in capacity expansion and optimum PV penetration levels when utilizing PV energy in small isolated systems.     

An efficient technique for geocast region holes in underwater sensor networks and its performance evaluation

In this paper, we present a complete Geocasting solution for underwater sensor networks. The model named Routing and Multicast Tree based Geocasting (RMTG) [1], [2] has been designed for underwater sensor networks. In our previous work [1], we proposed and simulated the RMTG model in terms of routing, route maintenance, link stability and data dispersion inside the geocast region in static as well as in mobile network conditions. In [3] we provided the theoretical improvement over the RMTG in terms of Geocasting for underwater sensor network by providing solutions for hole/void area detection inside the geocast region and a solution to cover the scattered nodes in the geocast region for guaranteed message delivery by means of boundary routing (that is routing by traversing all the faces of a particular geocast region). Here, the work in [3] has been enhanced, the model is named as Routing and Multicast Tree based Geocasting with Hole Detection (RMTG-HD). A detailed analysis and performance evaluation of the proposed model has also been provided. The simulation results show that the proposed model provides an efficient distribution of data in the geocast region in terms of packet delivery ratio, boundary routing delay, hole detection delay and handling of node mobility.     

全差分放大器(二)

5 应用电路 研究典型应用时,假设放大器的工作频率满足a(f)＞＞1,并且假设采用对称反馈,即β1=β2=Rg/Rg Rf. 5.1 输入电源端接 双端接通常用于高速系统,以降低输电线路反射并改进信号的完整性.双端接情况下,源端输出阻抗和终端端接与传输线阻抗匹配.源端输出阻抗值一般为50 Ω、75 Ω、100 Ω和600 Ω.采用差分输入源时,端接置于线路两端.采用单端输入源时,端接置于传输线和地之间.     

Submerged vs. Solid-State Conversion of Soybean Meal into a High Protein Feed Using Aureobasidium pullulans

The goal of this study was to assess the performance of Aureobasidium pullulans in converting soybean meal (SBM) into high protein feed using the submerged and solid-state processes. High solid loading rates (SLR) were evaluated for each process, i.e., 10–25% for submerged and 35–70% for static solid-state fermentation. During the submerged fermentation, 10% SLR was considered the best performer due to the high amount of cell density, low residual carbohydrates, and high protein titers, while 40% SLR resulted in the high protein yields and low residual carbohydrates during the static solid-state fermentation. The solid-state fermentation was conducted in a 14-L paddle-type reactor at 50% SLR, and periodic mixing resulted in a protein titer of ~58% at 72 hours of fermentation. Overall, results showed the feasibility of scaling up these processes in converting SBM to a high protein feed ingredient for animal diet.     

Renewable energy credit driven wind power growth for system reliability

Environmental concerns over electric power generation from conventional sources has led to widespread public support for renewable energy sources. Governments throughout the world have responded by providing various forms of financial incentives to promote power generation from renewable energy sources. The rapid growth of wind power since the last decade has primarily been driven by governmental subsidies. Long-term growth of wind power should, however, be driven by sustainable market mechanisms. A potential solution is to recognize monetary values to the environmental benefits from renewable energy sources, and to specify targets for their growth. The environmental benefits from wind sources can be leveraged to allow market competition of these sources with the less costly conventional generating sources. A probabilistic method to evaluate the impact of renewable energy credit and wind penetration level on the cost and adequacy of power generating systems is presented in this paper. The technique incorporates reliability and economic analyses and is applied to a published test system to illustrate the results and their influence on key system variables. The paper provides useful information to system planners and policy makers on wind energy application in electric power systems.