BLIND PARAFAC SIGNAL DETECTION FOR UNIFORM CIRCULAR ARRAY WITH POLARIZATION SENSITIVE ANTENNAS

The received signal of the polarization sensitive array is proved to have trilinear model characteristics. The blind parallel factor（PARAFAC） signal detection algorithm for the polarization sensitive array is proposed. The trilinear alternating least square （TALS） algorithm is used to abtain the source matrix, and then the matrix is judged. Simulation results show that the bit error rate （BER） of the detection algorithm is close to that of the non-blind decorrelating method and the algorithm works well under the array error condition. BER difference between the non-blind method and this algorithm is less than 2 dB under a high SNR. The algorithm is blind and robust. The channel fading, the direction of arrive（DOA） imformation and the polarization information are needless in the algorithm.

Arrangement of High-standard Basic Farmland Construction Based on Village-region Cultivated Land Quality Uniformity

As an important constitute of land consolidation, high-standard basic farmland construction is an important means to protect the quantity, quality and ecological environment of cultivated land. Its target not only lies in the increase of cultivated land quantity, but also the improvement of cultivated land quality, agricultural production conditions and ecosystem environments. In the present study, the quality evaluation method and construction arrangement of cultivated land were explored to facilitate the process of decision-making and implementation for high-standard basic farmland construction(HSBFC) with administrative village as the unit. Taking the land comprehensive improvement project area in Quzhou County, Handan City, Hebei Province as a case study, the whole process of the study comprised of three steps: 1) establishment of the evaluation model of cultivated land quality uniformity based on regional optimum cultivated land quality, and construction of the uniformity evaluation index system from the aspects of soil fertility quality, engineering quality, spatial quality and eco-environment quality, according to the new concept of cultivated land quality; 2) calculation of cultivated land quality uniformity by grading indicators, assigning scores and weighting sums, exploring the local homogenization characteristics of regional cultivated land quality through spatial autocorrelation analysis, and analyzing the constraints and transformative potential of barrier factors; 3) arrangement of HSBFC according to the principle of concentration, continuity and priority to the easy operation. The results revealed that the value of farmland quality uniformity for the administrative villages in the study area was between 7.76 and 21.96, and there was a difference between various administrative villages. The regional spatial autocorrelation patterns included High-High(HH), Low-Low(LL), High-Low(HL) and Low-High(LH). These indicate that regional cultivated land quality has local homogenization characteristics. The most restrictive factors in the study area were the medium and low transformation difficulty indexes, including soil organic matter content, farmland shelterbelt network density, field regularity and scale of the field. In addition, there were also high transformation difficulty indicators in some areas, such as sectional configuration. The project area was divided into four partitions: major construction area, secondary construction area, general construction area, and conditional construction area. The cultivated land area of each subarea was 1538.85 ha, 1224.27 ha, 555.93 ha, and 1666.63 ha, respectively. This comprised of 30.87%, 24.56%, 11.15% and 33.42% of the total project area, respectively. The evaluation model and index system could satisfy the evaluation of farmland quality and diagnosis of obstacle factors to facilitate the subsequent construction decision. The present study provides reference for the practice of regional HSBFC, and a new feasible idea and method for related studies.

A comparative study of seismic provisions between International Building Code 2003 and Uniform Building Code 1997

This study focuses on the comparison of the Uniform Building Code （UBC） 1997 and International Building Code （IBC） 2003 in relation to the seismic design and analysis of special steel moment resisting frame buildings （SMRF）. This paper formulates a numerical study of a steel SMRF building, studied in four different situations, namely： as an office building in San Francisco; as an office building in Sacramento; as an essential facility in San Francisco, and as an essential facility in Sacramento. The analytical results of the model buildings are then compared and analyzed taking note of any significant differences. This case study explores variations in the results obtained using the two codes, particularly the design base shear and drift ratios as they relate to different locations and occupancy use. This study also proves that IBC 2003 is more stringent for the redundancy factor under design category E for the SMRF building, and drift limits for essential facilities.

Optimization of tensile strength for new type acetone-urea-formaldehyde furan resin using uniform design

In this study,the 24 h tensile strength of new type acetone-urea-formaldehyde furan resin (nitrogen content 3%) was investigated by uniform design optimization.Four independent variables such as acetone:formaldehyde molar ratio (mol/mol),solution pH value,reaction temperature (℃) and reaction time (min) were considered in the experiments.U13(134) uniform design was employed and the equation of 24 h tensile strength model was obtained after 13 experimentations.The 24 h tensile strength was optimized by applying single factor experiments and stepwise non-linear regression analysis.Minitab (Minitab 15 trial version) and MATLAB (R2010a trial version) were used for data analysis.The t-value and p-value indicate that the major impact factors include the interaction effect of solution pH value and reaction temperature (X2X3),the linear terms of acetone:formaldehyde molar ratio (X1),reaction time (X4) followed by the square effects of acetone/formaldehyde molar ratio (X1X1).The optimized results were achieved with the acetone:formaldehyde molar ratio (mol/mol) at 3:1,solution pH value at 6.0,reaction temperature at 70℃,and reaction time at 140 min,respectively.This method can not only significantly reduce the number and cost of the tests,but also provide a good experimental design strategy for the development of furan resin.The investigation shows that the predicted results of 24 h tensile strength are consistent well with the experimental ones.

Measurement of pore diffusion factor of porous solid materials

Internal diffusion of molecules in porous materials plays an important role in many chemical processes.However, the pore diffusion capacity of porous materials cannot be measured by conventional catalyst characterization methods. In the present paper, a pore diffusion factor, the ratio of the diffusionconstriction factor to the pore tortuosity of the porous materials, was proposed to measure the diffusion ability of pores inside solid materials, and a method was proposed for measuring the diffusion factor using a well-defined and uniform pore size material as a reference. The diffusion factor was calculated based on the effective diffusion coefficients and the diffusion-constriction factor and pore tortuosity of the reference porous materials. The pore diffusion factor measurement can be performed at room temperature and atmospheric pressure. The pore diffusion factor of conventional porous materials was found to be much smaller than 1, indicating that there is a lot of room for improving the diffusion ability of the conventional catalysts and adsorbents, and could be significantly increased through adding small number of fibers into the conventional porous materials as template.

Evaluation of environmental factors to fatigue performance of asphalt mixes

This paper studies the effect of different environmental factors, including the axle load weight, environmental temperature, vehicle speed, and the aging level of asphalt, on the fatigue performance of asphalt mixes based on four-point bending beam fatigue tests. A fractional factorial design method named ＂uniform design＂ was applied in experimental design. The relations of the environmental factors to initial stiffness, fatigue life, phase angle and cumulative dissipated energy were established with the general linear modeling method. It is found that there exists very good correlativity between the environmental factors and the fatigue performance indices of asphalt mixes. The coefficients of total correlation are mainly beyond 0. 95. The results indicate that the consideration of the effect of environmental factors is necessary in the fatigue performance evaluation on real asphalt pavement.

不同放电倍率下软包锂离子电池非均匀生热表征方法

软包锂离子电池非均匀的温度分布严重影响其循环性能、使用寿命和安全性。针对软包锂离子电池生热的建模表征复杂且精度不高的问题,提出了一种基于生热分布因子的软包锂离子电池非均匀生热表征方法。将电池划分成不同区域,并将生热分布因子引入Bernardi生热公式中获取不同区域的生热率;通过传热和优化数值模拟求解电池的温度分布,同时辨识不同区域的生热分布因子,分析了软包电池生热非均匀分布特性;采用三次样条差值法推导了生热分布因子与放电倍率的对应关系,研究了不同放电倍率下生热分布因子的演化规律。实验结果表明,该方法所建立的热模型在2.75 C和3.75 C下的温度估计值的平均绝对百分比误差最大不超过1.55%,该方法能够准确估计电池非均匀的生热率,并实现电池温度分布特性的有效表征。

大孔隙参数对斜坡非均匀渗流与稳定性的影响

为揭示降雨条件下大孔隙参数对斜坡水分非均匀运移与稳定性的影响,基于两域模型与稳定系数场原理,建立降雨入渗下斜坡非均匀渗流与稳定性求解模型,并借助COMSOL Multiphysics多物理场有限元平台,编制相应的模型求解程序,通过大孔隙土柱降雨试验验证数值模型的合理性,对比均匀流与非均匀流条件下斜坡体积含水率和点稳定系数,分析大孔隙参数(大孔隙占比ω_(f)、两域导水系数之比μ、大孔隙经验参数r_(w))对斜坡渗流场及稳定系数场的影响规律。结果表明:相比不考虑大孔隙,考虑大孔隙时的基质域和大孔隙域表层体积含水率分别增长7.7%和降低5.1%,入渗深度分别增长83.3%和150.0%;边坡浅层失稳面积增大3.9%。基质域和大孔隙域入渗深度均随大孔隙占比ω_(f)的增大而减小;随着大孔隙域与基质域饱和渗透系数之比μ增大,两者入渗深度变化趋势相反,即μ越大,基质域入渗深度越小,大孔隙域反之;两者与经验参数r_(w)无显著关系。至降雨结束,基质域表层土体体积含水率已达最大值;大孔隙域则随着ω_(f)和μ的增大而增大,但几乎不受经验参数r_(w)的影响。非均匀流条件下,边坡水分交换沿着剖面从上往下分为负交换区、正交换区和无交换区,水分交换平衡深度与基质域入渗深度变化趋势一致;水分交换负交换区与正交换区的深度均存在一个峰值,并随大孔隙占比ω_(f)的增大而减小,随着μ和r_(w)的增大而增大。不同参数取值下,边坡均为浅层失稳破坏,ω_(f)和μ越大,失稳层深度越大,表层点稳定系数越小,因此大孔隙不利于边坡稳定。

基于粗糙集理论的均匀设计阿魏酸合成工艺因素规律的方法研究

目的利用粗糙集理论研究药物合成生产过程中生产因素之间的内在规律,探求最优合成工艺方案的方法。方法采用粗糙集理论方法,以阿魏酸合成工艺为案例,利用均匀设计试验预处理,形成基于粗糙集的决策表,建立粗糙集规则模型。通过决策规则分析工艺因素对试验指标的影响,优选最佳合成工艺。结果阿魏酸合成工艺的反应时间水平与阿魏酸收率水平呈线性增加的趋势(P<0.01),原料配比、吡啶量因素水平与阿魏酸收率水平并没有线性增加的趋势(P>0.05)。当试验三因素都取7水平时,试验结果最好,为最佳组合。结论粗糙集理论方法能够全面地分析药物合成工艺因素与试验结果之间的内在动态规律,为提高药物合成工艺质量,提出了一种独特的优选方法和思路以供参考。

播种量对浅埋滴灌宽幅匀播春小麦农艺性状及产量的影响

为研究筛选甘肃河西地区浅埋滴灌条件下春小麦最佳播种量,以宁春4号为试材,研究了不同播种量对浅埋滴灌条件下春小麦产量构成、农艺性状及产量的影响。结果表明,在浅埋滴灌宽幅匀播栽培条件下,随着播种量的增加春小麦的株高也随之逐渐提高,穗长和穗粒数随播种量增加均呈先增后降趋势。春小麦播种量为675万粒/hm^(2)时,穗长最长,为8.02 cm;穗粒数最多,为38.05粒;千粒重也较高,为39.4 g;折合产量最高,为8175.0 kg/hm^(2),且均显著或极显著高于其余处理。建议在甘肃河西地区春小麦浅埋滴灌宽幅匀播栽培中播种量以675万粒/hm^(2)为宜。

横向感应加热装置功率因数的研究与优化

横向磁通感应加热技术因其连续加热金属薄板带材的优异性能一直是近年来研究的焦点。为了满足节能环保要求,提高加热系统的功率因数可加强系统能源的利用率同时降低设备的成本。基于对45钢薄带加热需求设计了横向感应加热装置,采用有限元数值模拟的方法研究结构参数与电激励参数对横向感应加热系统功率因数的影响,并结合各参数对加热系统功率因数的影响规律对加热模型进行优化。结果表明,优化后模型与初始模型相比,系统的功率因数上升0.048,相对不均匀度下降5.15℃。优化后的模型有效地提高了系统的功率因数,并改善了带材的温度均匀性。

国产雪茄茄芯烟叶工业发酵条件单因素优化研究

【目的】通过单因素实验和均匀设计探索不同发酵参数对雪茄品质的影响规律,确定不同产区雪茄烟叶适宜采用的工业发酵条件。【方法】通过单因素实验探索了温度、初始水分、相对湿度和发酵时间对不同品种雪茄烟叶(德雪1号、德雪3号、德雪7号、海南9A、楚雪14)原料品质的影响。以致香成分总含量为衡量指标,通过均匀设计确定了不同品种雪茄烟叶的最优组合发酵参数。【结果】(1)随着温度的升高,还原糖和总糖含量逐渐降低,致香成分含量呈先降低后升高趋势,植物碱含量呈先升高后降低的趋势。当温度为30℃时,致香成分含量最高(除楚雪14)。(2)随着初始水分的升高,还原糖、总糖含量呈下降趋势,致香成分含量呈先上升后下降趋势。当初始水分为30%~35%,致香成分总含量较高。(3)随着相对湿度的升高,植物碱含量逐渐降低,还原糖含量逐渐增加。当相对湿度为80%时,致香成分含量最高。(4)总氮和植物碱含量在发酵过程中逐渐降低,总糖、还原糖和致香成分总含量在发酵过程中呈先上升后下降的趋势。当发酵天数为21~28d时,致香成分含量最高。(5)均匀设计表明,德雪1号、德雪3号、德雪7号较适采用低温30℃低湿70%发酵37d,海南9A较适采用低温30℃低湿70%发酵22d,而楚雪14较适采用高温50℃低湿70%发酵21 d。【结论】温度、初始水分、相对湿度和发酵时间对国产雪茄烟叶品质具有显著影响。德雪系列原料采用低温发酵可在保留其香气丰富度的前提下,减少刺激性和杂气;海南9A原料采用低温发酵可以提升香气丰富度;楚雪14采用高温发酵可以提升成熟度,降低杂气和刺激性。

基于均匀试验法的清水混凝土清水效果影响因素研究

通过均匀试验法研究了水胶比、胶凝材料用量、矿渣掺量、砂率对清水混凝土清水效果的影响,以混凝土表面色差、气孔率、裂缝率为指标,建立了量化评价清水混凝土清水效果的方法,使用二项式逐步回归分析建立了清水混凝土配合比参数对清水效果影响的方程,并得到最优配合比。结果表明,水胶比对清水混凝土清水效果影响最大,胶凝材料用量次之,砂率主要影响混凝土的表面气孔率和表面裂缝率,矿渣掺量对清水效果没有明显影响;清水效果最好的配合比为水胶比0.43,胶凝材料用量475 kg/m^(3),矿渣掺量25%,砂率0.40。

改进萤火虫算法的武器目标分配问题研究

武器目标分配(WTA)是指挥控制和任务规划领域的关键问题之一,萤火虫算法求解武器目标分配问题具有参数设置简单、执行效率高等优点。针对传统萤火虫算法易陷入局部极值,收敛速度和精度不高的弊端,从以下三个方面进行改进:初始化萤火虫序列编码时融入PWLCM混沌优化以提高全局搜索能力;设置受迭代次数控制的服从半高斯分布的非均匀步长因子以兼顾算法的搜索能力和收敛性;设计基于排序的萤火虫更新策略同时融入交叉变异操作以提高算法的效率和准确性。为验证改进算法的先进性,先利用其求解4种典型测试函数的最优解,再求解WTA问题,并与传统萤火虫算法进行对比,仿真实验结果表明,改进后算法的评价函数值提高了2.1%,迭代次数减少了52.9%,改善了传统算法易陷入局部极值的缺点,提高了收敛速度和精度,提升了武器目标分配的效果。

一穴四粒型孔立式大豆精量排种器设计与试验

为了适应大豆等距穴播栽培新型农艺要求,结合大豆精量排种技术设计了一种一穴四粒型孔立式大豆精量排种器,并对充种距离进行了设计与理论分析,使得穴内种子分布均匀。通过EDEM离散元软件,对型孔间隙、型孔布置形式和型孔数进行了单因素试验,在此基础上以排种盘转速、型孔深度和充种倾角为试验因素进行三因素五水平正交旋转仿真试验,以满穴率、合格率和漏播率为试验指标,应用Design-Expert 13软件对试验数据进行分析。得到回归模型和三因素对指标的影响关系,排种盘转速、型孔深度和充种倾角对各个指标有极显著影响,排种盘转速和型孔深度交互对合格率和漏播率有显著影响。基于回归模型进行参数优化,结果表明:当排种盘转速为26.45 r/min,型孔深度为7.35 mm,充种倾角为53°时,满穴率为83.16%,合格率为95.81%,漏播率为4.18%。对该优化参数组合下的排种器进行田间验证试验,结果表明:合格率均值为94.80%,合格率与仿真结果误差为1.01%,试验结果与优化结果相吻合,验证了仿真优化的可靠性,满足大豆精量播种要求。

仔猪均匀度与初生重的营养影响因素研究进展

仔猪初生重和均匀度是影响产房成活率的关键指标,而产房成活率是衡量现代养殖企业生产成绩的重要指标之一。随着遗传选育技术的持续突破,母猪窝均产仔数及断奶头数呈现出逐年增长的趋势,但这一进步也伴随着仔猪初生重和均匀度的降低。初生重和均匀度降低与仔猪的存活及其后续的生长发育密切相关,目前影响仔猪出生重和均匀度的因素主要有窝产仔数、品种、营养因素、胚胎在子宫中的位置、胎次、季节等。文章综述了采食量、蛋白质、功能性纤维、功能性氨基酸等营养因素对仔猪初生重和均匀度的影响及其可能的调控机理,并给出了合理的推荐值,以期通过营养调控手段改善仔猪初生重和均匀度,为饲料配方的优化设计提供参考。

恒温水浴锅温度性能影响因素的测试研究

本文依据JJF 2019-2022《液体恒温试验设备温度性能测试规范》,使用Vtest-1101型温度自动检定系统和GDW-216型高低温试验箱,在不同环境温度和液位条件下,对HH-4型恒温水浴锅的温度偏差、均匀度和波动度的性能进行实验测试。

逐步回归法优化填料改性与助剂提高烟草薄片浆料留着率的研究

采用了均匀实验设计方法和多元二次回归方程,研究了不同填料改性剂(烟叶碎片浆或针叶木浆、阳离子淀粉、硬脂酸钠、六偏磷酸钠)以及三元助留剂(壳聚糖、阳离子瓜尔胶、膨润土)对浆料留着率和碳酸钙分布均匀性的影响。结果表明,各因子贡献率中,壳聚糖、瓜尔胶、膨润土和针叶木浆更有利于提高浆料留着率。在烟叶碎片浆和针叶木浆的双因素交互作用图中,存在5种不同的变化趋势。大生产(不改性)烟草薄片的浆料留着率为68.8%,抗张强度为0.378 kN/m。通过回归方程优化参数并经实验验证,采用烟叶碎片浆和针叶木浆改性,再结合多元助剂,所得烟草薄片的浆料留着率分别达92.9%和94.9%,抗张强度分别提高了30.2%和28.8%。碳酸钙包裹烟叶碎片浆或针叶木浆形成的复合体,均能相对均匀分散在烟草薄片中。

阿德福韦酯片的制备研究

目的:优化阿德福韦酯片的处方。方法:采用均匀设计法,以填充剂比为因素A,崩解剂为因素B,润滑剂为因素C,以溶出度相似因子作为考察指标。结果:最优化的条件为填充剂比(乳糖、预胶化淀粉比为2.6),崩解剂(5.2%交联聚维酮),润滑剂(0.5%硬脂酸钙),3批验证试验的f_(2)均大于50,与参比制剂溶出行为相似,平均累积溶出度90%以上。结论:该处方设计合理,易于操作,体外溶出度良好。

非均匀沥青混合料不同影响因素下劈裂性能研究

为研究不同影响因素下非均匀沥青混合料的力学特性,在不同加载速率和试验温度条件下,开展不同离析程度沥青混合料的劈裂试验。结果表明:同一级配类型沥青混合料发生不同程度离析后,混合料内部沥青胶浆含量越多,劈裂强度受温度和加载速率变化影响越显著;开级配沥青混合料发生集料离析后,内部细集料越多,结构沥青越多,则劈裂强度越高。AC-13沥青混合料在各离析程度下比OGFC-16沥青混合料表现出更优的劈裂性能。