Design of a broadband dielectric resonator antenna and its application in low sensitivity frequency beam‐scanning array with wide scanning angle and suppressed sidelobes

In this paper, a broadband dielectric resonator antenna (DRA) with a simple H‐slot feeding structure is proposed. The broad bandwidth (~45%) and uni‐directional radiation enable this DRA suitable to work as a radiation element in the construction of a beam‐scanning array with not only low frequency sensitivity which is important for accurate angle estimation of in‐coming targets, but also a wide scanning range. Moreover, stable coupling coefficients are established around all the above three resonances with respect to its corresponding feeding line, ensuring a low sidelobe level (SLL) across the whole operating frequency range. In order to realize such a DRA, a latticed rectangular structure is utilized to generate the lower two resonances, while the upper resonance is generated by its H‐shaped feeding slot. The shape of the latticed dielectric resonator is also modified according to a 3‐D printed fixing structure for an accurate installation. A 20‐element beam‐scanning prototype is demonstrated and manufactured. The range of scanning angle is from ?36° to +13° within the bandwidth of 10 to 16 GHz, corresponding to a frequency sensitivity of only 122.5 MHz/^o. The achieved SLL are smaller than 19 dB for all scanning beams. The above performance indicates that, this array is very suitable for near‐range radar systems requiring an accurate angle estimation.     

Satellite-Based Water Quality Mapping from Sequential Simulation with Parameter Outlier Removal

The satellite-based regression model provides the data model that identifies water quality for inland and coastal waters. However, the satellite regression usually depends on the selection of observation, satellite data, and model type. A resampling simulation technique, such as sequential simulation using geographically weighted regression (GWR simulation), can be applied in generating multiple realizations for water quality estimation to reduce the sampling effect and consider spatial heterogeneity. Traditional models often result in considerable underestimation in extreme observations. The GWR simulation provides the best goodness of fit and spatial varying relationship between observed water quality and remote sensing considering parameter outlier and noise removal for parameter stability. This simulation model can increase the sampling diversity from various observations and reduce the neighboring effects of observations using outlier and noise removal. The model that handles spatial uncertainty and heterogeneity is a novel tool for inferring the characteristics of water quality from a series of sample subsets.

     

传统村落多维价值评价及遴选——以歙县35个传统村落为例

徽州传统村落核心价值的挖掘对于针对性保护发展策略的提出至关重要。以徽州35个非重点传统村落为研究对象,构建徽州传统村落价值评价指标体系,综合运用SPSS因子分析、线性加权对徽州传统村落进行多维价值评价方法进行探析,以期通过多维价值评价遴选出综合价值较弱但具有某一方面或多方面价值的村落。研究结果显示:依据本文的价值评价指标体系共遴选出7个方面的村落价值,由评价结果共筛选出18个综合价值较弱但具有独特价值的村落划定为特色型村落进行保护。     

基于空间句法的传统村落保护规划编制应用的思考——以国家级历史文化名村唐模为例

传统村落保护规划的编制是解决传统村落保护发展基础性和全局性的工作。运用空间句法的相关理论与技术对唐模古村进行空间解析,利用量化后的空间分析结果对传统村落保护规划中的保护区划划定、街巷路网调整、功能结构布局等重要规划内容提供了依据。廓清了空间句法在传统村落保护规划中应用的若干问题,为传统村落保护规划编制提供了可借鉴的技术路线和修正的思考。     

《绿色建筑评价标准》分析与设计对策

绿色建筑的实施效果依赖于设计人员对相关评价标准的理解和执行,通过对2014版《绿色建筑评价标准》的编制特点进行分析,研究其在建筑设计阶段涉及到的87项评价条款,根据不同专业及技术措施对其分类统计,计算出不同专业及技术措施的得分情况,根据这些数据分析绿色建筑设计工作的特点及侧重方向,结合建筑设计阶段8个设计专业的100余项申报文件在不同设计阶段的分布情况,总结出绿色建筑设计过程中设计人员在不同设计阶段的设计任务及工作重点,提出绿色建筑的设计对策。     

皮尔格轧机冷轧不锈钢管回弹预测模型的建立与验证

以皮尔格LG60轧机轧制304不锈钢管为例,研究皮尔格轧机冷轧不锈钢管回弹预测模型。首先通过单向拉伸试验及数据处理的方法得到材料的分段非线性本构方程;其次根据钢管轧制的塑性变形规律结合增量理论,得到变形过程中各应变分量的计算方法,并把钢管变形过程中的受力状态由三向应力状态转化为单向应力状态,利用材料的卸载定律建立冷轧钢管的回弹预测模型;最后通过大型有限元模拟软件DEFORM-3D进行完整轧制过程的3维有限元模拟仿真,并利用皮尔格轧机进行实际轧制试验验证来检验回弹预测模型的可靠性与正确性。结果表明,本模型精度较高,对皮尔格轧机孔型设计及实际生产中成品管尺寸精度控制有重要指导意义。     

基于FRFT的LFM信号的检测及其参数估计

针对LFM信号的检测及参数估计等问题,先对现有的检测方法如Wigner-Ville、FRFT等进行研究,在FRFT变换的基础上提出基于预判法与FRFT变换相结合的算法。通过仿真分析,验证了该方法能有效对L F M信号的参数进行估计,同时降低了计算量。     

Influence of static pre-loading on the dynamic bending strength of concrete with particle element modeling

Experimental tests show that static pre-loading has a significant effect on the dynamic strength of concrete.Based on meso-scale particle element model,numerical simulations of dynamic bending tests with pre-loading are performed.Complete stress–strain relationships are then obtained.Significant increase in dynamic strength is found when the pre-loadings are imposed within the elastic limit of concrete.However,when the imposition of pre-loadings reaches the plastic or softening range,dynamic strengths may gradually decrease along with the increase in pre-loadings.The distribution of energy components and the failure modes are discussed to explain the mechanisms of the phenomena.     

Evaluation research on applicability of rapid iodide migration test

The applicability of the rapid iodide migration test was systematically studied. Comparative experimental tests of different test conditions, including several external voltages, test durations, concrete ages and mixing proportions, were carried out to make clear the transport behaviors of iodide under parallel electric fields. Numerical simulations were also done using the finite element method to found the correlation between chloride and iodide transport behaviors. The test and numerical results show that the chloride transport behaviors of RIM and RCM tests have a good correlation under the several conditions used in the present paper. Moreover, the influence of external conditions （external voltages, test durations） on the test results is small. Thus, it can be concluded that the RIM method is available to determine the chloride penetration resistance of the chloride-eroded structural concrete.     

6CrW2Si钢渗碳后热轧形变制作冷剪刀的研究

6CrW2Si钢渗碳后经热轧形变可使渗层碳梯度平缓,碳化物分布均匀,消除了表层网状碳化物;淬火后可得到细的马氏体组织,并使残余奥氏体量减少;回火后硬度为HRC60～62。分析认为,可以用热轧形变量大小控制渗碳层的碳梯度。该工艺用于金属冷剪刀上使用寿命提高一倍。