大学生时间管理倾向与拖延行为的关系:自我控制的中介作用

目的探讨自我控制在时间管理倾向与拖延行为之间的中介作用。方法采用青少年时间管理倾向量表、自我控制量表和一般拖延行为量表对573名大学生进行测量。结果时间管理倾向各维度与自我控制存在显著正相关,时间管理倾向各维度、自我控制与拖延行为存在显著负相关,自我控制在时间价值感与拖延行为之间起着完全中介作用,在时间监控观、时间效能感与拖延行为之间中起着部分中介作用。结论大学生时间管理倾向通过自我控制影响拖延行为。     

时间视角下时间领导、时间效能感和员工创造力的关系:下属依赖的调节作用

目的应用社会认知理论,从时间视角出发探讨时间效能感在时间领导与员工创造力关系的间的中介作用,以及下属依赖的调节作用。方法采用领导-员工配套问卷的方式收集443份有效问卷数据,并运用SPSS和Amos分析工具对数据进行分析。结果时间领导对员工创造力具有显著正向影响;时间效能感在时间领导和员工创造力之间起部分中介作用;下属依赖不仅负向调节时间领导和时间效能感之间的关系,而且还负向调节时间效能感在时间领导与员工创造力间的中介作用。结论时间领导有利于提高员工时间效能感和员工创造力,但会因个体下属依赖程度有所差异。     

大学生情绪智力、自我效能感和社会支持与应激承受能力的关系

目的探讨大学生情绪智力、自我效能感和社会支持与应激承受能力的关系。方法采用情绪智力量表、应激承受能力量表、一般自我效能感量表、社会支持量表对742名大学生进行研究。结果个体的情绪智力能预测其应激承受能力;一般自我效能感和社会支持与应激承受能力存在正相关;一般自我效能感和社会支持在情绪智力预测应激承受能力的过程中起部分中介作用。结论大学生的情绪智力水平会影响其一般自我效能感和社会支持水平,最终影响其应激承受能力。     

网络英语学习者创新能力和自我效能感与学业成绩的关系

本研究目的探讨网络英语学习者创新能力、自我效能感和学业成绩的关系。为提高网络英语学习者学业成绩提供心理学依据。方法选取广东白云学院网络英语学习者450名学生为被试,使用大学生网络英语学习者自我效能感量表和创新能力测验对网络英语学习者自我效能感和创新能力进行了测量。结果自我效能感在网络英语学习者创新能力中对学业成绩的影响过程中起了中介变量的作用。结论网络英语学习者不仅应该注重学习过程创新能力的培养,也需要自我效能感的提升。建议为提高网络英语学习者学业成绩提出了切实可行的有效途径。     

辱虐管理与员工离职倾向：有调节的中介模型

目的基于自我认同理论,结合前人实证研究,探讨辱虐管理对员工离职倾向的影响机制。方法通过对299份全职员工的有效调查问卷进行共同方法偏差检验、验证性因子分析及回归分析等来验证假设。结果辱虐管理对员工知觉到的领导排斥有正向影响;领导排斥感在辱虐管理与员工离职倾向之间起部分中介作用;领导认同正向调节辱虐管理与领导排斥感之间关系以及领导排斥感的中介效应,即员工的领导认同水平越高,辱虐领导行为引发的领导排斥感越强,进而使得员工离职倾向越为强烈。结论辱虐管理对员工离职倾向的影响中,领导排斥感在两者间存在中介作用,而领导认同具有调节作用。     

大学生产品卷入度对冲动性网络购物的影响

本研究采用问卷法对224名大学生施测,探究产品卷入度与冲动性购买倾向对大学生群体网络冲动性购买行为的影响及作用方式。结果显示,冲动性购买倾向与网络冲动性购买行为总体正相关,二者关系受到产品卷入度水平及其认知成分的调节作用,当产品卷入度或其认知成分水平较低时,高冲动性购买倾向的被试比低冲动性购买倾向被试更容易发生网络冲动性购买行为,而当产品卷入度或其认知成分水平较高时,冲动性购买倾向对网络冲动性购买行为的影响趋于消失。     

年轻驾驶员自我效能感对驾驶技能的影响

目的探索年轻驾驶员自我效能感对驾驶技能的影响。方法采用中文版驾驶员自我效能感量表和驾驶技能量表对400名年轻驾驶员进行测量。结果男性驾驶员的驾驶技能得分比女性驾驶员高。驾驶员自我效能感得分与驾驶技能得分呈显著负相关。回归分析发现,驾驶员各人口学因素和自我效能感得分可以有效地预测题目一并解释35.9%,题目二37%,题目三18.6%,题目四23.5%,题目五30.1%,题目六21.7%,题目七10.4%和总分36.6%的变异率。结论年轻驾驶员自我效能感是影响驾驶技能的一个核心因素。     

认知需求在消费选项、时间与决策规避行为之间的调节

本研究以中学教师为被试,采用问卷调查的形式对选项数量、时间压力对消费者决策规避的影响以及消费者个体的认知需求水平在此过程中起到的作用进行研究。结果发现,选项数量为1比选项数量为2时消费者更倾向于规避决策;时间压力存在比时间压力不存在时消费者更倾向于规避决策。并且,个体的认知需求水平在选项数量与决策规避的关系中起到了调节作用。认知需求高的消费者的决策规避在两种选项数量之间差异较大,而认知需求低的消费者则差异较小。     

压力对工作倦怠的影响

目的:探讨企业客户服务人员工作压力、一般自我效能感与工作倦怠的关系。方法:采用问卷调查法对金融、物业、销售行业292名客户服务人员进行调查。结果:(1)工作压力与工作倦怠的玩世不恭和成就感低落2个维度显著正相关,一般自我效能感与工作倦怠的情绪衰竭、玩世不恭、成就感低落3个维度均显著负相关;(2)工作压力对女性的影响比男性大,男性的一般自我效能感显著高于女性;(3)未婚员工比已婚员工表现出更大的焦虑和忧郁,工作压力更大;(4)国有企业、民营企业、外资企业客服人员的工作压力依次增大;(5)一般自我效能感在工作压力与工作倦怠的关系中起到了中介作用。结论:工作压力越大,工作倦怠越严重,一般自我效能感在工作压力与工作倦怠的关系中起到了中介作用。     

环境暴力暴露、暴力态度对社会民众心理安全感的影响

目的考察社会民众心理安全感的基本状况以及环境暴力暴露、暴力态度对民众心理安全感的影响。方法对随机抽取的278名一般社会民众开展问卷调查。结果暴力暴露与暴力态度、心理不安全感之间存在显著正相关,与心理确定感之间存在显著负相关;暴力态度与心理不安全感有显著正相关;心理不安全感与心理确定感有显著负相关。暴力态度在环境暴力暴露与心理不安全感间有显著的中介作用。结论可见减少日常环境中的暴力线索暴露,改变民众的暴力态度是维护民众心理安全感的有效手段。     

PeliGRIFF,a parallel DEM-DLM/FD direct numerical simulation tool for 3D particulate flows

The problem of particulate flows at moderate to high concentration and finite Reynolds number is addressed by parallel direct numerical simulation. The present contribution is an extension of the work published in Computers & Fluids 38:1608 (2009), where systems of moderate size in a 2D geometry were examined. At the numerical level, the suggested method is inspired by the framework established by Glowinski et al. (Int J Multiph Flow 25:755, 1999) in the sense that their Distributed Lagrange Multiplier/Fictitious Domain (DLM/FD) formulation and their operator-splitting idea are employed. In contrast, particle collisions are handled by an efficient Discrete Element Method (DEM) granular solver, which allows one to consider both smoothly (sphere) and non-smoothly (angular polyhedron) shaped particles. From a computational viewpoint, a basic though efficient strategy has been developed to implement the DLM/FD method in a domain decomposition/distributed fashion. To achieve this goal, the serial code, GRIFF (GRains In Fluid Flow; see Comput Fluids 38:1608–1628, 2009) is upgraded to fully MPI capabilities. The new code, PeliGRIFF (Parallel Efficient Library for GRains in Fluid Flow) is developed under the framework of the fully MPI open-source platform PELICANS. The parallel computing capabilities of PeliGRIFF offer new perspectives in the study of particulate flows and indeed increase the number of particles usually simulated in the literature. Solutions to address new issues raised by the parallelization of the DLM/FD method and assess the scalable properties of the code are proposed. Results on the 2D/3D sedimentation of a significant collection of isometric polygonal/polyhedral particles in a Newtonian fluid with collisions are presented as a validation test and an illustration of the class of particulate flows PeliGRIFF is able to investigate.     

High-resolution field desorption/ionization fourier transform ion cyclotron resonance mass analysis of nonpolar molecules

We report the first field desorption ionization broadband high-resolution (m/Deltam(50%) approximately 65 000) mass spectra. We have interfaced a field ionization/field desorption source to a home-built 9.4-T FT-ICR mass spectrometer. The instrumental configuration employs convenient sample introduction (in-source liquid injection) and external ion accumulation. We demonstrate the utility of this configuration by generating high-resolution positive-ion mass spectra of C(60) and a midboiling crude oil distillate. The latter contains species not accessible by common soft-ionization methods, for example, low-voltage electron ionization, electrospray ionization, and matrix-assisted laser desorption/ionization. The present work demonstrates significant advantages of FI/FD FT-ICR MS for analysis of nonpolar molecules in complex mixtures.     

A flow injection on-line multiplexed sorption preconcentration procedure coupled with flame atomic absorption spectrometry for determination of trace lead in water, tea, and herb medicines

One of the limitations in previous flow injection (FI) sorption preconcentration procedures in a knotted reactor (KR), which have been carried out exclusively with a single continuous sample injection over a certain period, is the relatively low retention efficiency (typically 40-50%). Although the sensitivity of such systems could be improved by properly increasing sample preconcentration time, sample loading flow rate, or both, further improvement of the sensitivity has been limited by the narrow linearity of the relationship between signal intensity and preconcentration time or sample loading time. In this work, a novel on-line FI multiplexed sorption preconcentration procedure with repetitive sample injections was developed to overcome the above problems in the previous systems. In contrast to previous FI preconcentration systems, the proposed multiplexed preconcentration procedure evenly divides a single longer sample injection step into several shorter substeps while the total preconcentration time is still kept constant. To demonstrate its merits, the proposed FI on-line KR multiplexed sorption preconcentration system was combined with flame atomic absorption spectrometry (FAAS) for determination of trace lead in water, tea, and herb medicines. The lead in the sample solution on-line reacted with ammonium pyrrolidine dithiocarbamate, and the resultant analyte complex was sorbed on the inner walls of the KR. The residual sample solution was then removed from the KR with an air flow. The above two steps were repeated eight times with a total preconcentration time of 120 s. The sorbed analyte was eluted from the KR with 4.5 mol L(-1) HCl for on-line FAAS detection. The present multiplexed preconcentration procedure with eight repetitive sample injections for a total preconcentration time of 120 s gave a retention efficiency of 92%, twice that obtained by one single sample injection preconcentration (47%). In addition, the linear ranges of the diagrams of absorbance against sample loading flow rate and sample loading time were extended, offering more potential for achieving high sensitivity by increasing sample loading rates or sample loading time compared to the previous one single continuous sample injection preconcentration procedure. At a sample loading flow rate of 3.6 mL min(-1) for a total preconcentration period of 120 s, an enhancement factor of 57 and a detection limit (3sigma) of 8 microg L(-1) were obtained. The precision was 1.4% (RSD, n = 11) at the 200 microg L(-1) level. The developed method was successfully applied to the determination of trace lead in various water samples, herb medicines, and a certified tea reference material.     

Assessment of a TD-Based Method for Characterization of Antennas

Antenna-characterization measurements are traditionally performed in the frequency domain (FD) through a vector network analyzer (VNA) in an anechoic chamber. Nevertheless, the high cost of the required setup strongly limits the possibility of using this approach. Starting from these considerations, a time-domain (TD)-based approach for characterizing antennas without using an anechoic chamber is assessed. As a matter of fact, instruments operating in TD are usually less expensive than VNAs; nevertheless, with appropriate data processing, they provide as much information. Particularly, it is demonstrated that the selection of an optimal time windowing is the main factor that guarantees a high accuracy level in the corresponding FD. The proposed approach leads to the accurate evaluation of the reflection scattering parameter S ₁₁(f) from time-domain reflectometry (TDR) data. The experimental validation is tested on a commercial radio-frequency identification (RFID) reader antenna, and the results are compared with reference VNA measurements performed in an anechoic chamber. The ultimate goal of this paper is to demonstrate that, through calibrated TDR measurements, along with an optimal time windowing, an accurate antenna characterization can be achieved.     

Hybrid fluorometric flow analyzer for ammonia

We describe a robust, highly sensitive instrument for the determination of ambient ammonia. The instrument uses two syringe pumps to handle three liquids. The flow configuration is a hybrid between traditional flow injection (FI) and sequential injection (SI) schemes. This hybrid flow analyzer spends approximately 87% of its time in the continuous flow FI mode, providing the traditional FI advantages of high baseline stability and sensitivity. The SI fluid handling operation in the remaining time makes for flexibility and robustness. Atmospheric ammonia is collected in deionized water by a porous membrane diffusion scrubber at 0.2 L/min with quantitative collection efficiency, derivatized on-line to 1-sulfonatoisoindole, and measured by fluorometry. In the typical range for ambient ammonia (0-20 ppbv), response is linear (r2 = 0.9990) with a S/N = 3 limit of detection of 135 pptv (15 nM for 500 microL of injected NH4+(aq)) with an inexpensive light emitting diode photodiode-based detector. Automated operation in continuously repeated, 8-min cycles over 9 days shows excellent overall precision (n = 1544 p(NH)3 = 5 ppbv, RSD = 3%). Precision for liquid-phase injections is even better (n = 1520, [NH4+(aq)] = 2.5 microM, RSD = 2%). The response decreases by 3.6% from 20 to 80% relative humidity.     

On-line separation and determination of bromate in drinking waters using flow injection ICP mass spectrometry

A flow injection (FI) system with a microcolumn of anion exchanger has been used to effect rapid on-line separation of bromate and bromide prior to quantitation by ICP mass spectrometry. Basic performance studies are described including the effect of key FI parameters, i.e., sample injection volume, carrier stream flow rate, and eluent concentration on system response. The new approach permitted ultratrace determinations of bromate in drinking waters, the main benefits being low limit of detection (0.13 microg/L based on a 500-microL sample injection), rapid analysis time (10 min/sample), and good precision (2.8% at the 5 microg/L level). Accuracy was checked via an EC-sponsored interlaboratory trial.     

FSI modeling with the DSD/SST method for the fluid and finite difference method for the structure

We present a fluid–structure interaction (FSI) modeling method based on using the deforming-spatial-domain/stabilized space–time (DSD/SST) method for the fluid mechanics part and a finite difference (FD) method for the structural mechanics part. As the structural mechanics model, we focus on the thin-shell model. The fluid mechanics equations with moving boundaries are solved with the DSD/SST method and the thin-shell structural mechanics equation is solved with a FD method, with partitioned coupling between the two parts. The coupling of the DSD/SST and FD solvers makes sure that the boundary conditions on the fluid-structure interface at the end of each time step are matched between the fluid and the structure. A hanging plate in vacuum under gravitational force is performed to validate the structure solver. In addition, a pitching plate in a uniform flow is simulated to validate the FSI solver. The present results are in reasonable agreement with data predicted by other methods.     

Optimization and characterization of a flow injection electrochemical system for pentachlorophenol assay

A flow injection (FI) electrochemical detection system has been developed and optimized for the determination of pentachlorophenol (PCP) in contaminated soil. PCP was oxidized to tetrachloro-1,4-benzoquinone (1,4-TCBQ) with a high yield using bis(trifluoroacetoxy)iodobenzene in 0.1 M tartaric acid, pH 2.0, at ambient temperature. Upon rapid reaction with immobilized glucose oxidase, the detection and amplification scheme was completed as the reduced form of 1,4-TCBQ or tetrachloro-1,4-hydroquinone was reoxidized to 1,4-TCBQ at the surface of the glassy carbon electrode (+ 0.40 V vs Ag/AgCl). Rapid electron exchange between the enzyme and its glucose substrate provided a non-rate-limiting current toward the electrode. The FI electrochemical system was linear up to 1 μM oxidized PCP with a detection limit of 10 nM and exhibited a reproducibility of ±0.6% over 165 repeated analyses during 14 h of continuous operation. When applied to PCP-contaminated soil samples, the results obtained from the FI electrochemical system compared well with those of the HPLC standard method.     

不同干燥方法对百合品质的影响

为了选择一种对百合品质影响较小的干燥方法,测定了3种不同干燥方法（FD：冷冻干燥;CD：对流干燥;VCD：真空对流干燥）处理后的百合样品的指标,如色差值、褐变相关酶活性、抗氧化能力及化学指标含量,并对各项指标间的相关性进行探讨。结果表明,FD样品的色差值最小,PPO、POD活性最高,水解氨基酸、多糖和生物碱含量也最多;FRAP抗氧化活性,VCD样品最好,FD样品次之。因此,冷冻干燥能更好地保存百合的营养物质,干燥后百合的品质也更接近新鲜百合,这为百合深加工提供了一定的理论依据。     

Motion estimation of high density crowd using fluid dynamics

ABSTRACT

Motion estimation (ME) being a fundamental process of crowd behavior analysis experienced real challenges at high densities due to visual ambiguities and occlusion problems etc. Various surveys reported in the past years summarize conventional ME methods for crowd behaviors at low/medium densities. In this paper, we focus on state-of-the-art fluid dynamics (FD) ME methods developed over the last one and the half-decade for high-density crowd analysis. A detailed discussion is provided on the development of FD ME methods explaining the strengths and weaknesses and viability of FD ME methods for anomaly detection at high crowd densities. Comprehensive experiments are performed comparing the performance of conventional and FD ME at varying crowd densities. Experimentation results show that conventional ME methods fail at high-density crowd whereas FD ME methods could estimate motion only at the global level. Still, research is required to meet the challenges of local ME at high crowd densities.