木材热风干燥室空气流场均匀性研究

针对木材在常规木材热风干燥室存在板材开裂、变形翘曲,板材最终含水率不均匀等问题,设计了可调控引导送 风罩和移动调节装置;转动定位螺母调节导流舌板位置可改变出风口大小：驱动电机带动滚轮转动,可实现风机支撑框 架整体沿X方向移动自动调节;利用计算流体力学( CFD)软件SC/Tetra对优化设计前后的干燥室内空气流场进行数值 模拟计算,并对气流速度特性进行测试分析。结果表明优化设计后的干燥室沿板材堆垛高度方向上各层气流速度偏差 可控制在±10%以内;空气流场分布的均匀性提高了70%。优化后的干燥室木材干燥质量和干燥效率得到明显提升。     

股权制衡使公司内部控制更有效吗？——基于通信设备制造业上市公司案例的思考

早前内部控制的研究主要集中于概念框架、影响因素及公司治理失效案例方面,缺乏重点考察股权制衡这一因素对内部控制的作用机理。股权结构是公司治理的基础,不同的股权结构决定了不同的企业治理结构,最终决定了企业内部控制的有效性。相对股权分散和一股独大的股权结构,股权制衡可优化公司内部控制。     

蓄电池生产线极板上料装置

针对蓄电池生产线包封工序中存在大量手工上料,铅粉危害操作人健康,提出了极板自动上料的方案,分析比较 各方案的优缺点,设计了极板上料装置。极板上料装置投入运用后,解决了极板包片机上料的瓶颈,降低了工人劳动强 度,提高了劳动生产率     

定长米粉切割装置

针对米粉在加工过程中出现切割面不平整、切削效率低、工作强度大等问题设计了一种定长米粉切割装置。该 装置动力元件选择交流电机,传动元件选用具有吸振与缓振功能的V型带轮传动,执行元件设计为一种四齿间歇性运动 圆盘结构,辅助元件为长方形机架与米粉进给装置,并对整机结构进行三维机构运动学仿真,结果表明所设计的定长米 粉切割装置机构设计合理,工作过程平稳可靠。     

微小螺钉输送和拧紧装置

针对目前电子电器类产品的微小螺钉装配时存在装配精度和速度上的不足,提出一种新型微小螺钉输送和拧紧 装置,设计了输送和拧紧装置的组成结构,介绍了装置中主要部件的工作原理,并分析了输送过程中输送轨道的倾斜角 度和输送管道的弯曲程度,采用机械振动和气动传输相结合以实现微小螺钉的排序和输送。该装置可以实现微小螺钉 装配的自动化,与传统的手工装配或半自动化装配相比,具有工作效率高、产品装配质量高和装配成本低等特点,主要用 于工业生产流水线上微小螺钉的自动化装配过程中。     

Community older adults’ attitude towards the use of assistive devices

This study investigates how older adults’ attitude patterns affect assistive devices’ (AD) use in a small-household context of Singapore. Community older adults with physical limitations (n = 481) completed face-to-face interviews for 90 min. Latent Profile Analysis analysed multiple indicators of attitudes towards ADs. Three groups were classified: positive attitude group (PAG); negative attitude group (NAG); and unwillingness to pay for ADs (UPG). PAG was most likely to use ADs, while UPG was least likely to use ADs. The findings are expected to help older adults age in place by improving equal distribution of technology resources that assist with daily tasks and activities.     

Nonparametric testing for long-horizon predictability with persistent covariates

We propose a testing procedure for long-horizon predictability via kernel-based nonparametric estimators of long-run covariances between multiperiod returns and persistent covariates. Asymptotic properties of the proposed tests are studied. As for implementation of the test, sieve bootstrap methods are employed to obtain reasonable approximation to the sample distribution of the test statistics. Monte Carlo simulations are conducted to verify the theoretical conjecture. Empirical analysis, using US monthly data from 1929 to 2011, are presented for testing stock return predictability of some forecasting financial variables. Long-term interest rates, unlike default spreads or price-earning ration, are found to show some forecasting power.     

On some new randomized item sum techniques

A recent quantified version of item count technique (ICT), called the item sum technique (IST), was developed by Trappmann et al. (2014 Trappmann, M., I. Krumpal, A. Kirchner, and B. Jann. 2014. Item sum—A new technique for asking quantitative sensitive questions. Journal of Survey Statistics and Methodology 2 (1):58–77. doi:10.1093/jssam/smt019.[Crossref] , [Google Scholar]). In this method, two subsamples are required to obtain reliable data on the sensitive issues. In this article, we propose three alternative item sum techniques by utilizing an additional randomization device. The main advantage associated with the current study is that in order to estimate population sensitive parameters, it requires only one sample to obtain reliable data on quantitative sensitive issue without jeopardizing the privacy of participants. Furthermore, it reduces the cost, effort, and time as compared to usual IST. It is also free from the requirement of finding optimum subsample sizes as in the usual IST. The mean and variance of these proposed estimators are also derived and compared with those of the usual IST. Through algebraic and nnumerical comparsions, it is observed that the proposed techniques perform better than the usual IST. Moreover, the proposed randomized IST 3 is observed to be unconditionally more effeicient than the proposed IST 1 and IST 2.     

在线设备更新问题的竞争策略及其风险补偿模型

本文基于一种设备在线租赁的基础上,提出了在线设备更新问题。运用传统竞争比方法分别研究了两阶段设备更新问题在有无利率情形下的在线竞争策略,并建立了相应的风险补偿模型,从而在线投资者可以根据自己的风险容忍度和预期选择最优的更新策略。市场利率的引入使得在线设备更新模型更复杂但更贴近于现实中的设备更新问题。最后,通过具体实例进一步说明了市场利率下在线竞争比更小,而且竞争比关于市场利率递减;同时也说明了风险补偿模型中最优约束竞争比要小的多。因此,投资者若考虑到资金的收益及市场风险因素后将会采取更加谨慎稳健的投资策略。     

评乔姆斯基的"普遍语法"理论

乔姆斯基的“普遍语法”理论的中心思想是:人脑有一种先天的特定结构或属性,即语言习得机制,它是人类学会使用语言的内因。“普遍语法”是乔姆斯基语法理论的核心,是对传统观念的一种挑战。研究“普遍语法”理论对认知心理学有着重要的启示,对进一步理解人类大脑如何形成语言能力具有重大意义。