纳米CaSO_4晶须改性聚氨酯密封胶的制备

通过三种聚醚制成的密封胶进行对比,具体考察了CaSO4晶须对密封胶力学性能的影响。结果表明,在单组分湿固化聚氨酯密封胶中添加纳米CaSO4晶须后,密封胶的剪切强度得到提高,硬度和弹性变化不大。使用CaSO4晶须替代气相二氧化硅,在降低成本的同时,密封胶的触变性仍然很好。     

丁二烯适宜贮存温度的研究

研究了贮存温度、时间、气相氧含量和铁锈含量对丁二烯中过氧化物生成量的影响,考察了丁二烯适宜的贮存温度.结果表明:丁二烯中过氧化物含量随着铁锈含量增加而同倍增加;当气相氧含量增加1倍,丁二烯中过氧化物含量提高21%;在对叔丁基邻苯二酚(TBC)为104 mg/kg、贮存时间为7 d条件下,当贮存温度大于21℃时,丁二烯中过氧化物量增加显著;丁二烯较适宜的贮存温度为18℃.工业装置生产运行表明:在18℃下贮存丁二烯是安全、稳定和节能的.将丁二烯贮存温度从13℃调整到18℃,可使其装置运行费用下降43%.     

基于宽度学习的结构沉降预测

结构监测是确保工程结构建设在施工和运营阶段安全的关键因素,因此采用合理有效的预测模型对结构沉降监测数据进行科学准确的预测成为了当前结构沉降预测研究的重点。针对传统预测方法与深度学习方法用于结构沉降预测存在的预测精度不够高、模型结构复杂、训练耗时等问题,提出了一种基于宽度学习的结构沉降时间序列预测模型。通过实测地铁地下隧道沉降监测数据对宽度学习、人工神经网络、支持向量回归和深度置信网络-支持向量回归预测模型的预测结果进行对比分析。实验结果表明:宽度学习系统(broad learning system,BLS)应用于结构沉降预测具有良好的效果,其训练速度更快,预测精度更高。验证了所提出的宽度学习算法应用于结构沉降预测的可实施性和有效性。     

High precision frequency measurement based on the characteristic of the fuzzy area

The phase difference change is random in the discrete fuzzy area by considering the limit of device resolution, which the device can not stably capture, and the precision of the measured value only reaches the level of ns, but the phase difference change in the concentrated fuzzy area is step by step, and the device can stably capture the change of ps. By using the fuzzy area conversion technology, a high precision frequency measurement is designed. Through computer control and frequency synthesis,the discrete fuzzy area is converted to the concentrated fuzzy area, the ps stability properties of phase difference change on the border of the concentrated fuzzy area is used, the precision can be improved two or three orders of magnitude, and the high precision measurement in a wide range is achieved.     

Design of hydraulic shift mechanism for AMT vehicles based on the collaborative optimization method

Based on multidisciplinary design optimization (MDO), a new design method is put forward for hydraulic shift mechanism of heavy-duty vehicle automated manual transmission (AMT). Taking a shift cylinder for example, the collaborative optimization (CO) method for the design problem of a cylinder is devided into one system level design optimization problem and three subsystem level design optimization problems. The system level is an economic model and the subsystem level is mechanics, kinetics, and a reliability model. Application of the multidisciplinary design optimization software iSIGHT modeling and solving, optimal solution of the shifting cylinder CO model is obtained. According to the optimal solution, oil cylinders are machined out and installed on the gearbox of an AMT system for the bench cycle shift test. The results show that the output force and action speed of the optimized mechanism can meet requirements very well. In addition, the optimized mechanism has a better performance compared to the structure of the traditional design method, which indicates that the CO method can optimize the design of hydraulic transmission.     

九龙山珍珠冲组砂砾岩储层改造技术研究与实践

四川盆地九龙山珍珠冲组砾岩储层基质孔渗条件差,非均质性强,裂缝及其溶蚀孔洞是重要的储集空间和主要的渗流通道。针对该区储层特征,结合室内评价实验和储层评价结果,对于裂缝发育的储层,采用土酸酸化;对于裂缝欠发育的储层,在酸化工艺无效的情况下开展加砂压裂工艺试验,通过施工管柱、施工参数的优选,成功地实施了对砾岩储层的加砂压裂改造,取得了一定的改造效果。     

基于PCA和DEA方法的十堰市物流效率分析

物流业是国民经济的重要组成部分,首先基于主成分分析法提取区域物流投入与产出的主要指标,然后建立基于DEA方法的区域物流发展效率评价指标与模型。进而将PCA和DEA分析法用于湖北省十堰市区域物流发展效率的实证研究中,根据所构建的评价指标与模型测算十堰市1995-2013年19个年度的物流发展效率,分析了十堰市各年度物流业的投入与产出不足,并为十堰市提出区域物流发展的建议。     

Duffing系统中微弱信号起始点的检测

为从时域上检测微弱信号在系统中出现的时间点,提出了一种基于Duffing系统的微弱信号起始点的间接检测方法.首先将微弱信号与Duffing系统自身的信号相叠加,混合测量后剔除其中Duffing系统产生的信号,再利用dmey小波对待测信号加入系统造成的轨道偏离过程进行时域分析,可较准确测出微弱信号的起始点.由于混沌系统本身对高斯噪声的自免疫特性,因此本方法具有一定的抗噪性.仿真结果显示:该方法能有效地从时域上检测到微弱信号的起始点,其相对误差可达到10-3s,可应用于心动信号特征参数的提取.     

从中国旅游区划研究看中国旅游发展趋势

旅游区划是揭示旅游资源与旅游业空间布局的重要手段,有助于从整体上把握旅游发展趋势.以时间为线索,从命名、范围、依据等方面对不同时期的区划方案进行回顾比较,并对其存在的问题及优缺点进行评述.基于旅游区划的演变对中国旅游业发展趋势进行分析,以期可以更科学合理地进行旅游区划,促使我国旅游业朝着"可持续旅游"方向迈进.