分形环单元八木天线的特性

介绍了应用分形原理设计环八木天线,采用分形环单元来替代传统环八木天线的圆环或方环,利用分形图形的空间填充特性来减小横向设计尺寸,以实现天线的小型化设计.以中心频率为900 MHz的Minkowski分形环单元八木天线为例,说明了天线的设计过程,设计结果表明该天线具有较为理想的技术指标,同时,相对于传统的环八木天线,采用分形结构可以使尺寸明显减小.     

一套针对高泥质疏松砂岩薄储层的识别技术——以珠江口盆地X油田为例

针对珠江口盆地X油田韩江组高泥质疏松砂岩段扩径严重引起测井曲线质量差、波阻抗属性叠置严重、储层薄且非均质性强等难题,形成的薄储层精细表征技术概括为"三步法"：①遗传化神经网络技术重构能得到反映真实地层特征的弹性曲线,进而解决在疏松砂岩井段因扩径严重导致测井曲线失真的问题;②针对高泥质疏松砂岩薄储层识别难的问题,新构建DVT敏感特征参数来区分砂岩与泥岩;③利用波形指示高分辨率反演方法预测高泥质疏松薄砂岩储层的空间展布。实际应用表明：该技术在X油田注水收效、调整井优化实施和开发调整方案井网设计等方面取得了较好的应用效果,解决了该油田3~5 m薄层精确描述的难题,形成了一套完整的针对高泥质疏松砂岩薄储层预测的技术流程。该技术对同类油藏表征和油田高效开发具有参考意义。     

聚氨酯橡胶与纺纱胶辊

从聚氨酯橡胶的特殊物理性能——高弹性、高耐磨、抗静电、耐油性等方面展开讨论,详细介绍了混炼型、浇注型、热塑型聚氨酯橡胶的加工工艺流程,重点分析了混炼型、浇注型聚氨酯橡胶的配方及其性能,并举例说明了德国拜尔公司KA8550热塑性聚氨酯橡胶的性能指标;从对比聚氨酯、丁腈橡胶的耐油、耐溶剂及电性能,分析了聚氨酯纺纱胶辊的应用特点及其性能指标.指出只要将材料国产化、工艺合理化,聚氨酯橡胶完全可以替代丁腈橡胶制造纺纱胶辊,且耐磨性能优、回磨周期长、节约能源,可大面积推广.     

STUDY ON GENETIC ALGORITHMS-BASED NIR WAVELENGTH SELECTION FOR DETERMINATION OF SOLUBLE SOLIDS CONTENT IN FUJI APPLES

ABSTRACT

The determination of soluble solids content (SSC) in intact apples was analyzed by means of near‐infrared spectroscopy using an acousto‐optic tunable filter technology. Genetic algorithms (GAs) were performed to select wavelengths within the range from 1,065 to 1,625 nm. Partial least squares regression (PLSR) model based on GAs was compared with the nonvariable selection. Furthermore, the majority of selected wavelengths that brought on that result have been analyzed with regard to the typical absorption bands of sugars and the low‐noise spectral signals. With the GAs approach, the spectral points were reduced from 88 to 17, and the low relative standard deviation of prediction (RSD_p) (6.02%) and high coefficient of calibration (0.914) were achieved. The results showed that PLSR combined with GAs not only simplified and optimized the calibration model, but also improved the prediction effect of the calibration model. It was concluded that the GAs‐based method extracted relevant SSC information from special spectral regions and left out the useless spectral points simultaneously.

PRACTICAL APPLICATIONS

The determination of soluble solids content (SSC) in intact apples is quite important for assessing the internal quality of fruit. However, the portable spectrophotometer did not provide a reliable spectral signal. The multivariate modeling of the entire spectra not only computes complexly, but also increases spectral interferences. In the present study, an acousto‐optic tunable filter spectrometer was used for analysis. Genetic algorithms (GAs) were presented for the wavelength selection in order to predict the SSC in intact apples, based on partial least squares regression of near‐infrared spectral data. The results demonstrated that the wavelength selection based on GAs can build a simple model and can improve the performance of the model. It was also shown that the GAs‐based method extracted relevant information from special spectral regions and left out the useless spectral points simultaneously. It is valuable to establish a nondestructive measurement for developing online sensing systems.

     

接枝增重蚕丝的活性染料染色

采用M和KE两类双活性基活性染料对甲基丙烯酰胺接枝增重蚕丝进行染色.应用正交设计方法,系统研究了温度、盐、碱和固色时间四个工艺因素对固色率的影响,优化了染色工艺.在此基础上,筛选出6只高固色率活性染料,其提升性和色牢度性能均较佳.     

柴油_渣油和沥青的脉动燃烧对比试验研究

在一变形的里克（Rijke)管中进行了柴油、渣油和沥青的脉动燃烧对比试验。试验发现容易燃烧的 燃料容易激起脉动,难燃燃料由于着火推迟,较难激起脉动,而必须加长尾管长度才能解决问题。当进风面积与燃烧腔截面积之比减小到一定程度时,对于渣油等难燃燃料,其脉动特性会向1／4波长管的脉动特性过渡;而对于柴油等易燃燃料,脉动特性不变。 试验表明,这种无阀脉动燃烧技术可使渣油、沥青等难燃物高效清洁地燃烧,这对于渣油等难燃燃料的利用有重要意义。     

真空联合堆载预压固结沉降计算方法的探讨

介绍了真空联合堆载预压路基沉降的方法,主要是分析在已有吹填土的深厚淤泥地段主固结沉降的计算方法,并结合工程实例,通过分析对比研究,得出了一些有益的结论。     

温度变化对钢梁受力性能的影响

基于构件的非线性位移应变关系,利用能量原理推导了钢梁在温度荷载和均布荷载共同作用下平衡方程以及钢梁应力和竖向位移的计算公式,并对一工字形截面钢梁力学性能受温度变化的影响进行了分析,由分析结果可知：温度变化对钢梁的力学性能影响较大。     

黏土地基膨胀导致桩身倾斜引起结构裂缝分析

以工程实例为依托,根据工程的地质条件及施工情况,探讨了黏土地基膨胀导致桩身倾斜引起的结构裂缝的现状、形成机理及产生原因,并对结构裂缝作了安全评估,为确保桩基稳定奠定了基础。     

油桃采后结合态香气变化规律及其与可溶性糖的关联性

以'瑞光1号'油桃为研究对象,研究其采后常温(20℃)和低温(1℃)贮藏下游离态和结合态香气物质变化规律.采用酶解法释放结合态香气物质,利用项空固相微萃取法结合气相色谱-质谱联用对油桃游离态和结合态香气物质分别进行定性和定量分析,并研究结合态香气物质与可溶性糖之间的相关性.结果 表明,油桃果实常温和低温贮藏条件下游离态...