摘要：Multi-cell processing （MCP） is capable of providing significant performance gain, but this improvement is accompanied by dramatic signaling overhead between cooperative base stations. Therefore, balancing the performance gain and overhead growth is crucial for a practical multi-base cooperation scheme. In this paper, we propose a decentralized algorithm to jointly optimize the power allocation and beamforming vector with the goal of maximizing the system performance under the constraint of limited overhead signal and backhaul link capacity. In particular, combined with calculating the transmission beamforming vector according to the local channel state information, an adaptive power allocation is presented based on the result of sum capacity estimation. Furthermore, by utilizing the concept of cell clustering, the proposed framework can be implemented in a practical cellular system without major modification of network architecture. Simulation results demonstrate that the proposed scheme improves the system performance in terms of the sum capacity and cell-edge capacity.

摘要：为提高翠碧一号上部烟叶打叶质量和出片率,明确打辊工艺对打后片烟结构、叶中含梗率和出片率的影响,采用均匀试验设计不同打辊转速组合,在打叶复烤生产线开展打叶实验,应用回归分析构建一至四级打辊转速与片烟结构、叶中含梗率和出片率的数学模型,利用模型对四级打辊转速参数进行了优化和验证。结果表明:大片率、中片率、大中片率和碎片率与打辊转速线性回归模型均在P<0.01水平显著,叶中含梗率与打辊转速线性回归模型在P<0.05水平显著,出片率与打辊转速线性模型相关系数为0.83,但在P<0.05水平不显著;在其他工艺条件恒定时,大片率、中片率、大中片率受一级打辊转速和二级打辊转速影响较大,碎片率受一级打辊转速和三级打辊转速影响较大,叶中含梗率受一级打辊转速影响较大,出片率受一级打辊转速、二级打辊转速和四级打辊转速影响较大;优化后一至四级打辊转速分别为585 r/min、590 r/min、680 r/min和690 r/min,较现行工艺大片率降低了9.59%、中片率提高了17.41%、出片率提高了1.33%,有效提升了翠碧一号上部烟叶的打叶质量。

摘要：Because of the integration of long term evolution （LTE） technology and mobile satellite communication systems, uplink access technology for LTE-based geo-stationary earth orbit （GEO） satellite has become a popular research topic for satellite system. In order to solve the problem of unreasonable design for physical random access channel （PRACH） signal structure and reduce the effect of time uncertainty, this paper proposes a novel random access preamble based on time pre-compensation （TPC） for LTE-Satellite （LTE-S） system. In this scheme, by applying the method of non-linear least squares, the user terminal （UT） can use and based on the transmission delay the receiving power to estimate the communication round trip delay （RTD） of the beam center and the satellite, RTD can be compensated before transmission. Therefore, the preamble length and duration can be reduced without related to the maximum of RTD. In order to verify the performance of the scheme, the MATLAB is used to build a test system. The simulation results show that the proposed preamble satisfies the requirements of LTE-S system, and the better performance than previous researches is obtained.

摘要：飞机机翼和发动机进气道的结冰导致飞行安全事故频发。针对飞机在寒冷气候下飞行会造成机翼和发动机进气道结冰的问题,开发一种可用于飞机防/除冰的电加热复合材料用增强织物。基于定制纤维铺放(Tailored Fiber Placement,TFP)技术,设计制备镍铬合金丝作为电热元件、玻纤平纹织物作为基底、涤纶线作为面线和底线的电加热织物。通过拉伸实验研究针迹步长、面线张力和布线速度等TFP工艺参数对电加热织物经向和纬向拉伸性能的影响,选择出最优工艺参数。以此参数制备出3种电热元件排列密度电加热织物,同时对其在不同电压下的电热性能进行评价。拉伸性能和电热性能测试结果表明:基于TFP技术制备的镍铬合金丝电加热织物经向和纬向拉伸强度保留率最高可达98.34%和95.71%;3种电加热织物35 s时均可达到最高平衡温度,当施加电压不变时,电热元件排列密度越大,织物最高平衡温度越高;所得研究结果可为飞机防/除冰用电热复合材料提供增强织物方案,对于飞机防/除冰用材料的研制具有重要意义。

摘要：Block matching has been used for motion estimation and motion compensation in the Au- dio and Video Standard (AVS) for years. While having an acceptable performance in describing mo- tion between frames, it requires quite a few bits to represent the motion vectors. In certain circum- stances, the use of global motion estimation and compensation would perform equally well or even better than the block matching in terms of motion accuracy, while it results in the coding of global motion model parameters. In this letter, we modify an AVS coder by adding (1) six global motion model parameters to the frame header, and (2) mode selection among INTRA, SKIP, INTER-16×16, INTER-16×8, INTER-8×16, INTER-8×8, and Global Motion Compensation (GMC) modes by La- grange optimal rate-distortion criteria. Simulation results demonstrate that over 0.1dB improvement in PSNR is obtained compared to the AVS coder for an average coded P-frame with the same bit- rate.

摘要：鸟类在输电铁塔上筑巢、栖息或飞行的行为可能导致与输电设备的接触,从而增加了短路、火灾和停电的风险。针对驱鸟装置供电方式单一与可靠性差的问题,设计了一种多源能量采集器,将摩擦纳米发电机与太阳能电池进行了集成式设计。采用双层摩擦结构的摩擦纳米发电机来提高风能的利用率,并结合太阳能电池实现输电铁塔上风能和光能的收集。实验结果表明外层发电结构的峰值功率是4500μW,内层发电结构的峰值功率是400μW,双层摩擦结构使发电效率提高了接近10%,在氙灯光照强度为20 W/dm^(2)下太阳能电池的最大开路电压为11.2 V,最大短路电流为40 mA。同时,基于LTC3588芯片设计了一种双通道功率管理电路,将摩擦纳米发电机与太阳能电池收集的能量经过能量存储、能量管理后为用电设备稳定提供3.3 V电压。采用该多源能量采集器驱动了计算器与蜂鸣器,为驱鸟供电与传感系统提供了新思路。

摘要：According to the theory of DBR, with the P-type DBR as an example, the electrical characteristics and optical reflection of the DBR are analyzed by studying the energy band structure with various graded region widths and doping densities. The width and doping density of graded region are decided through a comparative study. The P-type DBR of 980 nm VCSELs is designed with Al0.9Ga0.1As and Al0.1Ga0.9As selected as the high and low refractive index material for the DBR. The 980 nm bottom VCSELs, which consists of 30 pairs P-type DBR and 28 pairs N-type DBR, are then fabricated. In P-type DBR, the width of graded region is 0.02 μm and the uniformity doping concentration is 2.5×10^18cm^-3. Its reflectivity is 99.9%. In N-type DBR, the width of graded region is also 0.02 μm and the uniformity doping concen- tration is 2×10^18cm^-3. Its reflectivity is 99.3%. The I-V curve shows that the series resistance of the device is about 0.05Ω. According to the theory of DBR, with the P-type DBR as an example, the electrical characteristics and optical reflection of the DBR are analyzed by studying the energy band structure with various graded region widths and doping densities. The width and doping density of graded region are decided through a comparative study. The P-type DBR of 980 nm VCSELs is designed, with Al0.9Ga0.1As and Al0.1Ga0.9As selected as the high and low refractive index material for the DBR. The 980 nm bottom VCSELs, which consist of 30 pairs P-type DBR and 28 pairs N-type DBR, are then fabricated. In P-type DBR, the width of graded region is 0.02μm and the uniformity doping concentration is 2.5×10^18cm^-3. Its reflectivity is 99.9%. In N-type DBR, the width of graded region is also 0.02 μm and the uniformity doping concentration is 2×10^18cm^-3. Its refiectivity is 99.3%. The I-V curve shows that the series resistance of the device is about 0.05Ω.

摘要：Computational diffusion kinetics(CDK),with a spirit of and being coupled with the computational thermodynamics(CT,or called as the CALPHAD technique),plays increasingly important role in the alloy design/optimization and microstructure control during the processing of advanced metallic *** paper is to highlight recent progress of CDK in research with great focus on novel Ti and Zr alloys,which was largely performed in the authors’*** ends with one representative example of the applications of CDK,coupled with CT,quantitative phase field,and three-dimensional(3D)statistical calculation,in designing the heattreatment schedule for the dual phase(αβ)Ti–6Al–4V alloys.

摘要：径向柱塞液压马达在中大型机械装备中应用十分广泛,然而因其内部存在冲击与疲劳磨损等问题,对径向柱塞液压马达的寿命与性能造成了一定的影响。针对上述问题,提出了一种改进粒子群算法优化径向柱塞液压马达内曲线的方法,该方法将等加速度曲线重构为含补偿区的等加速度曲线,以减小冲击和接触应力突变值。以粒子群算法(Particle Swarm Optimization,PSO)为基础,加入自适应非线性动态权重与多子种群竞争优化策略,构建一种改进粒子群算法,对各区段角度进行重新分配,重新生成含补偿区的径向柱塞液压马达内曲线。对比优化前后的结果表明,最大接触应力下降了2.54%,最大接触应力处的突变值下降至0;接触应力不再阶跃式上升,有上升过程,冲击较小。该研究能够为径向柱塞液压马达的设计提供参考,有效减缓疲劳与磨损,降低冲击影响,从而延长液压马达的使用寿命。

摘要：燃油压力调节阀是船舶动力系统的重要组成部件,主要用于稳定供油系统的燃油压力,减小系统压力波动对燃机的影响。基于现代船舶航程远、体量大的特点,设计了一种适用于大流量燃油系统的压力调节阀,分析了其工作原理,研究了调节阀内的燃油流动模型,通过数值仿真分析了内部流场,搭建了一套基于实际供油系统的试验系统,对两种不同工况的系统参数进行了试验。结果表明,所设计的燃油压力调节阀结构合理,使用该阀后,系统流量、压力、响应时间符合燃机使用要求。