正交型光热偏转光谱法及其差分构型研究

本工作设计了一种新的差分式光热偏转光路构型,光路的优点是只使用单一的位置传感器,可随意调节样品池和参考池的距离,电学补偿和差分光路装置简单,容易调整,可以有效地消除溶剂空白吸收的影响和泵浦激光功率起伏的影响。文章还讨论了该差分构型的原理,差分响应公式和基本实验参数。获得的结晶紫和钴的检测下限分别为8.0×10^(-10)mol/L和60ng/ml,对应的最小吸光度分别为1.2×10^(-8)和5.4×10^(-8)。

激光光热折射光谱法及其差分构型的研究

本工作借助于透镜对探测束发散的会聚补偿作用,设计了一个光热折射光谱的差分式光路构型,可以有效地消除溶剂空白吸收的影响和泵浦激光强度起伏与指向噪音的影响。本差分构型光路简单,容易实现样品池和参考池的定位与调整。文章还详细讨论了光热折射光谱法的实验参数,获得的结晶紫和钴的检测下限分别为1.0×10^(-9)mol/L和0.28 μg/ml,对应的最小吸光度为1.5×10^(-8)和2.5×^(-7)。

实时带钢表面质量检测算法研究与应用

针对现有带钢表面质量检测技术在检测精度、数据实时吞吐量等方面存在的问题,提出了一种基于纹理特征编码的带钢表面缺陷检测方法。首先,利用高斯滤波器的差分响应模拟人类视觉的纹理感知模型,在原始图像空间内进行缺陷可疑点检测;然后对疑似缺陷位置进行纹理特征的提取与编码,在纹理特征编码空间内完成缺陷的精密定位。实验结果表明,该方法可以对带钢表面常见的氧化、孔洞、边裂、麻点等十几种不同类型缺陷进行精确地检测,降低了系统的误检率,同时提高了缺陷检测的识别率和算法的计算效率。

环境规制和农业科技进步的关系分析——基于波特假说的研究

波特假说主要从动态的角度论证了环境规制和农业科技进步之间的正向变化关系。而在安徽省1990-2008年的农业生产数据的基础上,选择合适的环境规制和农业科技进步的指标变量,运用Johansen协整分析方法验证了安徽省农业生产中的环境规制和农业科技进步的关系也符合这一假说,Granger因果关系检验说明了安徽省环境规制是农业科技进步产生的原因,脉冲响应分析和方差分析则更深入地从定量的角度分析了环境规制对农业科技进步影响滞后的趋势和影响程度。由实证分析可以看出,只是从静态角度来分析,环境规制是不利于农业的科技进步的;但从长期效益来看,环境规制有利于农业的科技进步。因此,在农业生态环境恶化的形势下,严格对农业废弃物的排放限制,制定较严格的农产品生产标准和产品质量标准,提高农民的环境意识和科技意识,通过强化环境规制来促使农业生产者提高农业生产技术,提高农产品品质和产品的市场竞争力就显得尤为重要。

Dynamic interacting relationships among international oil prices, macroeconomic variables and precious metal prices

From the perspective of long-term and short-term, the methods of TY causality test, generalized impulse response function, variance decomposition were used to investigate the impacts of international oil prices and macroeconomic variables on Chinese gold, silver and platinum prices, but also the feedback effects of Chinese precious metal prices under this impact. The results show that international oil prices play an important role in precious metal price variation both in long-term and short-term, and exchange rate only has an effect in short-term, while interest rate is ineffective in predicting precious metal prices. In addition, precious metal prices have some feedback effects on international oil prices and interest rate in short-term.

基于自适应压缩感知的大规模MIMO-OFDM系统信道估计方法

大规模多输入多输出(MIMO,multiple-input multiple-output)是物联网(IoT,Internet of things)中为多种机器类设备高效提供连接服务的解决方案,而高效的连接服务需要准确的信道估计。针对大规模MIMO系统的下行信道估计中导频开销大和估计归一化均方误差(NMSE,normalized mean square error)性能较差的问题,以压缩感知(CS,compressed sensing)理论为基础,在结合信道空间域共同稀疏性的同时,利用相邻时隙差分信道冲激响应(CIR,channel impulse response)的稀疏性更低的特点,大大减少了导频发送的数量。在重构算法上,提出了一种二阶段差分估计算法,将一组连续相关时隙内的信道估计分为两个阶段,并结合自适应压缩感知的思想以实现快速准确的CIR估计。仿真结果表明,所提出的二阶段差分信道估计算法不仅在估计的NMSE性能、数据传输速率上相比已有的基于CS的多重测量向量(MMV,multiple measurement vector)算法有显著的提高,而且在运行时间复杂度上也有一定的降低。

金融发展、财政支持与自主创新关系的实证分析

基于1991—2015年安徽省经济发展和科技创新数据,运用johanseni协整分析方法实证分析了金融发展、财政支持与自主创新的关系,得出了金融发展、财政支持对自主创新具有不同程度的促进作用。运用Grange因果关系检验说明了金融发展、财政支持是自主创新的驱动因素,脉冲响应和方差分析则从更深层次定量地研究了金融发展、财政支持对自主创新的影响程度和变化趋势。由实证分析结果可以看出:金融发展与人力资本对自主创新的促进作用较弱,而财政支持和产业升级对自主创新的促进作用较强。解释这一影响机理,并借助实证分析,从完善金融市场、加强政府科技创新支持力度、提高人力资本质量和优化新产品市场方面提出政策建议。要提升企业的自主创新能力,需完善金融市场,健全金融制度,建立包括科技贷款、科技担保、股权融资、科技保险及科技租赁等的科技融资渠道,为企业自主创新提供宽松的融资渠道,降低科技创新风险,进一步提升金融在自主创新中的诱导和激励作用。加强政府财政的科技创新支持力度,设立科技专项资金,支持基础研究、应用开发、成果转让及产业发展。加强人力资本投入,提高人力资本质量,突破人力资本对自主创新的"门槛效应"。以产业结构调整、产业转型与升级为先导,完善技术市场,培育新产品市场,形成以需求为导向、竞争为压力的创新动力机制。

Optimization of electrical discharge machining process parameters for Al6061/cenosphere composite using grey-based hybrid approach

Fly ash has congregated considerable attention as a potential reinforcement for aluminum matrix composites(AMCs)to enhance selective properties and reduce the cost of fabrication.However,poor machinability of such AMCs limits their application.The present study focuses on the preparation of cenosphere fly ash reinforced Al6061alloys by compo casting method.X-ray diffraction analysis of the prepared AMCs exposes the presence of cenosphere particles without any formation of other intermetallic compounds.In this study,electrical discharge machining(EDM)was engaged to examine the machinability of the prepared metal matrix composite(MMCs).The measured performance characteristics for the various combinations of input process parameters were considered to be MRR,EWR and SR.Face centered central composite design(CCD)of response surface method(RSM)was employed to design the number of experimental trials required and a hybrid approach of grey-based response surface methodology(GRSM)was imposed for predicting the optimal combination of processing parameter in EDM process.Generous improvement was observed in the performance characteristics obtained by employing both the optimal setting of machining parameters.The optical3D surface profile graphs of the ED machined surface also revealed the improvement in surface quality and texture employing the optimal processing conditions proposed by hybrid GRSM approach.

Correction of Dynamic Error Result from Measurement System Limitations

The main cause of dynamic errors is due to frequency response limitation of measurement system. One way of solving this problem is designing an effective inverse filter. Since the problem is ill-conditioned, a small uncertainty in the measurement will came large deviation in reconstncted signals. The amplified noise has to be suppressed at the sacrifice of biasing in estimation. The paper presents a kind of designing method of inverse filter in frequency domain based on stabilized solutions of Fredholm integral equations of the fast kind in order to reduce dynamic errors. Compared with previous several work, the method has advantage of generalization. Simulations with different Signal-to-Noise ratio （SNR） are investigated. Flexibility of the method is verified. Application of correcting dynamic error is given.