摘要：To meet the requirements of the low power Zigbee system, VCO design optimizations of phase noise, power consumption and frequency tuning are discussed in this paper. Both flicker noise of tail bias transistors and up-conversion of flicker noise from cross-coupled pair are reduced by improved self-switched biasing technology, leading to low close-in phase noise. Low power is achieved by low supply voltage and triode region biasing. To linearly tune the frequency and get constant gain, distributed varactor structure is adopted. The proposed VCO is fabricated in SMIC 0.18-#m CMOS process. The measured linear tuning range is from 2.38 to 2.61 GHz. The oscillator exhibits low phase noise of-77.5 dBc/Hz and -122.8 dBc/Hz at l0 kHz and 1 MHz offset, respectively, at 2.55 GHz oscillation frequency while dissipating 2.7 mA from 1.2 V supply voltage, which well meet design specifications.

摘要：This study presents a new method of 4-pipelined high-performance split multiply-accumulator (MAC) architecture, which is capable of supporting multiple precisions developed for media processors. To speed up the design further, a novel partial product compression circuit based on interleaved adders and a modified hybrid partial product reduction tree (PPRT) scheme are proposed. The MAC can perform 1-way 32-bit, 4-way 16-bit signed/unsigned multiply or multiply-accumulate operations and 2-way parallel multiply add (PMADD) operations at a high frequency of 1.25 GHz under worst-case conditions and 1.67 GHz under typical-case conditions, respectively. Compared with the MAC in 32-bit microprocessor without interlocked piped stages (MIPS), the proposed design shows a great advantage in speed. Moreover, an improvement of up to 32% in throughput is achieved. The MAC design has been fabricated with Taiwan Semiconductor Manufacturing Company (TSMC) 90-nm CMOS standard cell technology and has passed a functional test.

摘要：In modern energy-saving replication storage systems, a primary group of disks is always powered up to serve incoming requests while other disks are often spun down to save energy during slack periods. However, since new writes cannot be immediately synchronized into all disks, system reliability is degraded. In this paper, we develop a high-reliability and energy-efficient replication storage system, named RERAID, based on RAID10. RERAID employs part of the free space in the primary disk group and uses erasure coding to construct a code cache at the front end to absorb new writes. Since code cache supports failure recovery of two or more disks by using erasure coding, RERAID guarantees a reliability comparable with that of the RAID10 storage system. In addition, we develop an algorithm, called erasure coding write （ECW）, to buffer many small random writes into a few large writes, which are then written to the code cache in a parallel fashion sequentially to improve the write performance. Experimental results show that RERAID significantly improves write performance and saves more energy than existing solutions.

摘要：This paper presents and verifies a new idea for constructing an ultrasonic motor （USM）. The stator contains several vibrators fabricated by bonding piezoelectric ceramics （PZTs） to a metal base. When two alternating current （AC） voltages with a 90° phase difference are applied to the PZTs, longitudinal and bending modes are excited in the vibrator. The bending vibrations of the vibrators are stacked to form the torsional vibration of the stator, ultimately generating longitudinal-torsional composite vibration. Both vibrators and the stator are excited to the resonance state. A standing wave is formed by superposition of longitudinal and torsional modes. The proposed motor is an in-plane vibration motor because the vibrations of the stator are in the circumferential plane. The finite element method （FEM） is used to validate the feasibility of the proposed motor. The fabricated stator contains five vibrators. The tested resonance frequencies of longitudinal and torsional modes are 44.42 kHz and 43.83 kHz, respectively. The stall torque is 0.3 N＇m and no-load speed is 45 r/min. The highest efficiency is 30%. The applied driving voltage is 100 Vo.p （peak voltage） at 43.9 kHz. The designed motor is a parallel-actuated integral motor. It allows the vibrators to operate synchronously, and overcomes asynchronous issues that occur in traditional multi-vibrator motors.

摘要：In this study, waste tire was used as raw material for the production of activated carbons through pyrolysis. ＇Fire char was first produced by carbomzation at 550℃ under nitrogen. A two tactortal design was used to optimize the production of activated carbon from tire char. The effects of several factors controlling the activation process, such as temperature （.830-930℃）, time （2-6h） and percentage ot carbon dioxide （70%-100%） were investigated. The production was described mathematically as a function of these three factors. First order modeling equations were developed for surface area, yield and mesopore volume. It was concluded that the yield, BET surface area and mesopore volume of activated carbon were most sensitive to activation temperature and time while percentage of carbon dioxide in the activation gas was a less significant factor.

摘要：While many techniques have been developed for the design of different types of antennas,such as wire antenna,patch antenna,lenses,and reflectors,these cannot be said general-purpose strategies for the synthesis and design of antennas to achieve the performance characteristics specified by ***,there has been an increasing need for the development of antenna design techniques because of the advent of 5 G and a variety of space,defense,biological,and similar applications,for which a robust and general-purpose design tool is not to be *** main objective of this study is to take a look at antenna design from the field manipulation point of view,which has the potential to partially fulfill this *** review the existing field manipulation techniques,including field transformation methods based on Maxwell’s and wave equations,point out some limitations of these techniques,and then present ways to improve the performance of these ***,we introduce an alternative approach for field manipulation based on two-dimensional(2 D)metasurfaces,and present laws of the generalized reflection and refraction that are based on 2 D surface ***,we explore how to overcome the limitations of conventional reflection and refraction processes that are strictly bounded by the critical ***,we provide some application examples of field manipulation methods in the antenna design,with a view on developing a general-purpose strategy for antenna design for future communication.

摘要：We present a new sense amplifier circuit for EEPROM memory. The topology of the sense amplifier uses a voltage sensing method,having low cost and low power consumption as well as high reliability. The sense amplifier was implemented in an EEPROM realized with an SMIC 0.35-μm 2P3M CMOS embedded EEPROM process. Under the condition that the power supply is 3.3 V,simulation results showed that the charge time is 35 ns in the proposed sense amplifier,and that the maximum average current consumption during the read period is 40 μA. The novel topology allows the circuit to function with power supplies as low as 1.4 V. The sense amplifier has been implemented in 2-kb EEPROM memory for RFID tag IC applications,and has a silicon area of only 240 μm2.

摘要：The design of optimal heterogeneous catalysts for N_(2)-to-NH_(3) conversion is often dictated by the scaling relations,which result in a volcano curve that poses a limit on the catalytic ***,we reveal a bowl active site that can break the scaling relations,through investigating the catalytic mechanisms of N_(2)-to-NH_(3) conversion on the lanthanide intermetallic electride catalyst LaRuSi by first-principles *** bowl active site,composed of four surface La cations and one subsurface Si atom rich in electrons,plays the key role in enabling efficient *** adaptive electrostatic and orbital interactions,the bowl active site promotes the adsorption and activation of N_(2) that delivers facile cleavage of N-N bond,while destabilizes the adsorptions of ^(*)NH_(x)(x=1,2,3)species,which facilitates the release of the final NH_(3) *** comparison with other electride catalysts isostructural to LaRuSi,we confirm the breaking of scaling relations between the adsorptions of ^(*)NH_(x) species and that of^(*)N on the bowl active ***,this bowl active site presents a design concept that breaks the scaling relations for highly efficient heterogeneous catalysis of N_(2)-to-NH_(3) conversion.

摘要：Role based access control is one of the widely used access control *** are investigations in the literature that use knowledge representation mechanisms such as formal concept analysis(FCA),description logics,and Ontology for representing access control ***,while using FCA,investigations reported in the literature so far work on the logic that transforms the three dimensional access control matrix into dyadic formal *** transformation is mainly to derive the formal concepts,lattice structure and implications to represent role hierarchy and constraints of *** this work,we propose a methodology that models RBAC using triadic FCA without transforming the triadic access control matrix into dyadic formal *** discussion is on two lines of *** present how triadic FCA can provide a suitable representation of RBAC policy and we demonstrate how this representation follows role hierarchy and constraints of RBAC on sample healthcare network available in the literature.

摘要：We design a grey wolf optimizer hybridized with an interior point algorithm to correct a faulty antenna array. If a single sensor fails, the radiation power pattern of the entire array is disturbed in terms of sidelobe level（SLL） and null depth level（NDL）, and nulls are damaged and shifted from their original locations. All these issues can be solved by designing a new fitness function to reduce the error between the preferred and expected radiation power patterns and the null limitations. The hybrid algorithm has been designed to control the array＇s faulty radiation power pattern. Antenna arrays composed of 21 sensors are used in an example simulation scenario. The MATLAB simulation results confirm the good performance of the proposed method, compared with the existing methods in terms of SLL and NDL.