论建筑施工项目中施工成本的控制

建筑施工成本控制是影响施工企业经济效益的重要因素。本文主要从施工成本控制的依据,施工成本控制的方法,施工过程中相关的注意事项三方面对施工成本控制进行浅述。     

贵州德江楠杆自然保护区地衣物种多样性初步研究

该文对采自贵州德江楠杆自然保护区的400余份地衣标本进行整理,经形态学、解剖学、化学分析方法以及分子系统学方法鉴定,共鉴定出地衣14科20属37种。其中,贵州新记录属6个,贵州新记录种24个。发现优势科2个:文字衣科Graphidaceae、石蕊科Cladoniaceae,及大量仅1属和属中仅1种的科,说明本区内地衣在科和属组成上的多样性与复杂性。该研究填补了该地区地衣资源调查的空白,为后续的地衣资源研究开发提供了理论依据。     

粘度对中性墨水书写性能的影响

主要讨论了粘度对中性墨水书写性能的影响.采用基体、色浆和水按照不同比例(wt%)混合的方法配制成中性墨水,通过调节基体的比例得到具有不同粘度的中性墨水,利用粘度计、书写检测划圆仪分别对墨水的粘度、书写性能进行了表征,结果发现,基体比例为60%(wt%)的中性墨水书写性能较好.     

高速铁路视景防真系统的应用研究

介绍了视景仿真软件Muhigen Creator和Vega的特点,结合高速铁路的实际情况,阐述了利用视景仿真软件Muhigen Creator建立高速铁路三维模型及应用Vega对模型进行实时驱动的方法,分析了高速铁路仿真的应用前景,特别是在火车上的应用。     

激励横向射流对超声速混合中大尺度结构影响的数值研究

本文对1 kHz激励横向射流对超声速混合中大尺度结构的影响进行了数值模拟。结果显示激励射流可以有效地刺激射流剪切层,使大尺度结构提早形成,对混合有积极影响,使主流和射流充分混合。     

生态翻译学视域下的文化负载词字幕翻译——以《西游降魔篇》为例

由于文化负载词在译语中缺乏对应语,因此如何成功地翻译电影字幕中的文化负载词无疑是一项艰巨的任务。生态翻译学理论为文化负载词的字幕翻译提供了全新的视域。以"三维"翻译原则为指导和判断标准,结合电影字幕翻译实例,探讨生态翻译学对电影字幕中文化负载词翻译的启示,以期获得最佳译文,从而更好地促进中英文化的交流。     

A new Markov regime-switching count time series approach for forecasting initial public offering volumes and detecting issue cycles

This study proposes a novel Markov regime-switching negative binomial generalized autoregressive conditional heteroskedasticity model for analyzing count data time series. We develop a likelihood-based method for parameter estimation and give the one-step-ahead forecasting algorithms for the mean, variance, and quantiles. An empirical analysis of both the U.S. initial public offering (IPO) and Chinese A-share IPO markets indicates that our method is very efficient in forecasting monthly IPO volumes and detecting hot/cold issue markets. The first-day IPO return is positively correlated with the IPO volume in a hot issue market but negatively correlated with the IPO volume in a cold issue market, in both the U.S. and Chinese IPO markets. However, the average first-day return in the previous hot issue market has a significant positive impact on the current IPO volume for only the U.S. IPO market. Our approach helps to more accurately model and understand the behavior of hot/cold IPO issue markets.     

基于轻量级深度卷积神经网络的绝缘子检测

在无人机巡检图像中,检测出绝缘子是实现输电线路状态分析的关键.本研究采用轻量级卷积神经网络代替传统的人工特征提取器,获取输入图像的深层特征;利用深度学习目标检测网络对所提取特征进行处理和训练学习,实现多尺度、多种类的绝缘子目标检测.实验结果表明:该方法可以准确快速地识别出以山林背景为主的瓷质和复合两类绝缘子,其检测精度...     

Microstructure, mechanical and thermo-physical properties of hot-pressed Al2O3-GdAlO3-ZrO2 ceramics with eutectic composition

A low cost chemical co-precipitation method was employed to fabricate nanoscale Al_2O_3-GdAlO_3-ZrO_2 powder with eutectic composition. A careful control of reaction conditions was required during the preparation. The synthesized nanopowders exhibited a particle size of 20-200 nm, and were highly dispersive and uniform. The results showed that calcination temperature had an important influence on the phase constituents of the nanopowders. With increasing the calcination temperature, a phase transformation from θ-Al_2O_3 to α-Al_2O_3 and a thermal decomposition from Gd_3 Al_5O_(12)(GdAG) to GdAlO_3 and α-Al_2O_3 occurred in sequence. A calcination temperature of 1300 ℃ was needed for the crystallization of α-Al_2 O_3. These nanosized powders were consolidated via hot pressing to produce a fully densified ceramic composite with eutectic composition. The Al_2O_3-GdAlO_3-ZrO_2 ceramic hot-pressed at 1500 ℃ exhibited a relative density of 99.4%, a flexural strength of 485 MPa and a fracture toughness of 6.5 MPa m~(1/2). The ceramic had a thermal conductivity of 1.9 W m K~(-1) at 1200 ℃ and a thermal expansion coefficient of 9.49 ×10~(-6) K~(-1) at 1100 ℃.     

一种适用于质量交换网络优化的节点非结构模型

质量交换网络（MEN）作为过程集成系统的新兴分支方向，具有提高资源利用效率和降低环境污染的双重效益。目前典型的超结构模型在MEN优化中已经取得了很好的应用，但超结构固定排列方式限制了模型中换热器匹配的灵活性和求解域的扩大。基于此，提出了一种新的有分流节点非结构模型，以节点的形式量化传质单元的匹配方式，实现传质单元在流股上的自由匹配，从而增强了单元匹配的灵活性。同时考虑到实际工程中有分流情况的出现，以分组数和分支数表示传质单元的有分流形式，进一步扩大了模型的求解范围。最后，通过2个实际MEN算例分析计算，验证了有分流节点非结构模型的有效性。