基于北斗卫星技术的交通服务系统

本文首先提出了基于GSM/GPS车船监控调度系统存在盲区的问题，然后介绍了基于北斗卫星技术的交通服务系统的整体组成以及主要功能，接着介绍了系统的终端设备并对该系统的文件传输子系统作了详细的论述。     

A biophysical implementation of a bidirectional graph search algorithm to solve multiple goal navigation tasks

The model presented here extends formal analysis (Hasselmo et al., Neural Networks, 15, pp. 689-707, 2002b) and abstract modelling (Gorchetchnikov and Hasselmo, Neurocomputing, 44-46, pp. 423-427, 2002a) of interactions within the hippocampal area (or other cortical areas), which can be flexibly used to navigate toward any arbitrary goal or multiple goals that change on a trial-by-trial basis. The algorithm is a version of a bidirectional breadth-first graph search implemented in simulated neurons using two flows of neural activity. The new model changes the continuous firing rate neuronal representations (Gorchetchnikov and Hasselmo 2002a) to more detailed compartmental versions with realistic parameters, while preserving the qualitative properties analysed previously (Hasselmo et al., 2002b, Gorchetchnikov and Hasselmo 2002a). The case of multiple goals being present in the environment is studied in this paper. The first set of simulations tests the algorithm in the selection of the closest goal. A small difference in distance between the simulated animal and different goals is sufficient for a correct selection. The second set of simulations studies the behaviour of the model when the goals have different saliences. A small salience-based difference between firing rates of the cells providing goal-related input to the model is sufficient for the selection of a more salient goal. This behaviour was tested in three types of environments: a linear track, a T-maze and an open field. Further investigation of quantitative properties of the model should allow it to handle cases when the exact location of the goal is uncertain.     

Structural behaviour of aeronautical tungsten carbide/carbon-coated titanium ball screws under space thermal-vacuum conditions

In view of the pressing need for improvements in space mechanisms and tribology research work, a thermal high‐vacuum mechanism test facility has been constructed at Rome ‘La Sapienza’ University. The purpose of this facility is to provide fundamental data on the performance of mechanical components and materials in high vacuum in order to test the validity of space mechanism designs. The facility also makes it possible to examine the behaviour of both mechanisms and materials under combined environmental factors, such as ultraviolet radiation, atomic oxygen and temperature. This paper reports on the behaviour of titanium recirculating ball screws provided by Umbra Cuscinetti SpA (Foligno, Italy) under thermal‐vacuum conditions. It is to be noted that these ball screws—well known in the aeronautical field—may be particularly attractive as a new generation of space mechanisms. A solid multilayer film of tungsten carbide/carbon (WC/C) was deposited on screw surfaces as a lubricant and was then compared with the case of no lubrication, which presently appears promising for many mechanisms. In order to compare experimental results, traditional stainless steel mechanisms were also tested and analysed. The requisites imposed by the space environment, as well as by contact mechanical stresses, have given useful information on a preliminary geometrical configuration and choice of materials, both of which are presented in this paper. Thermal‐vacuum effects on overall ball screw efficiency and on ball screw coating friction and wear are also reported and commented on herein as well as numerical contact simulations of crack mechanisms.     

Depression in Multiple Sclerosis: A Quantitative Review of the Evidence.

The published literature on depression in multiple sclerosis (MS) is reviewed quantitatively. The authors report mean effect sizes for 20 studies comparing depression scores of MS patients with those of healthy participants (d=1.07) and 21 studies comparing depression scores of MS patients with those of patients who have other chronic conditions (d=-0.14). The confidence interval for the mean overall MS-medical comparison included 0. However, subgroups of patients with chronic fatigue and spinal-neuromuscular conditions were more and less depressed than MS patients, respectively. Results indicate that a majority of MS patients with mild to moderate disability levels are distinguishable from healthy people in terms of depressive symptoms. However, the depression-disease link is complex and not specific to this form of demyelinating illness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Specific Sexual Orientation-Related Difference in Navigation Strategy.

During spatial navigation, women typically navigate an environment using a landmark strategy, whereas men typically use an orientation strategy. To examine the as yet unknown effects of sexual orientation on these normative sex differences, this study required 80 healthy heterosexual and homosexual adult men and women to provide directions from experimental maps for 4 routes. The frequency and type of strategy used by each participant were computed. Expected sex differences were demonstrated, and a robust cross-sex shift was shown by homosexual men in using landmarks. This remained after controlling for differences in mental rotation, directional sense, and general intelligence. The findings may limit the number of putative neurodevelopmental pathways responsible for sex differences in navigation strategy utility. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Are Trends in Work and Health Conditions Interrelated? A Study of Swedish Hospital Employees in the 1990s.

[Correction Notice: An erratum for this article was reported in Vol 14(1) of Journal of Occupational Health Psychology (see record 2008-19186-009). This particular study was based upon a unique database (the Springlife database), with repeated questionnaire self-reports from hospital staff in the ?rebro Regional Hospital in Sweden regarding work environment and mental health in the years 1994, 1995, 1997, 1999, and 2001. The Springlife database was referred to in the text and references of the article noted above, but it should have been more clearly acknowledged. Herewith the authors want to make this late acknowledgement. The database actually started in the fall of 1993 with the regional hospital's physicians and continued with all hospital staff during the spring 1994.] Swedish hospital personnel were followed over an 8-year period, characterized by staff redundancies and restructuring processes. Self-rated and administrative data sets from 1994 to 2001 allowed for studying long-term consequences of organizational instability for staff health and work conditions. The aim was to identify, on a work-unit level, trends in work and health conditions and their interdependence. Regression analysis showed a downward trend in mental health and an upward trend in long-term sick leave. Increasing trends of work demands were accompanied by deteriorating mental health, and decreasing time to plan work showed the strongest association with increasing long-term sick leave. Job satisfaction and support were decreasing. A stable short-term sick leave rate over years related to lack of support. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Snow Entrainment Coefficient Estimated by Field Observations and Wind Tunnel Experiments

The boundary condition for concentration of snow particles at the bed is necessary to calculate snowdrifts by a numerical analysis model. The flux type or the gradient type boundary conditions are reasonable. An idea of an entrainment coefficient of snow particle at the snow surface is useful. The values of the coefficient are considered to be a function of the density and viscosity of the working fluid and the properties of snow particles. In this paper, the values of the coefficient are estimated based on the k–ε turbulence model and the distribution of snow particle flux observed at the Mizuho Station, Antarctica in 2000, assuming the steady, fully developed flow over a flat snow surface. The snow entrainment coefficient is two or three orders smaller than the sand entrainment coefficient in a river. The reason is that the specific weight of snow particles in air is much larger than that of sand particles in water.     

Allowable gas temperature at outlet from furnace subject to slagging

The paper is devoted to substantiation and prediction of the allowable gas temperature at the outlet from a furnace subject to slagging. The non-optimality of values recommended by effective methodical instructions regarding the design of furnace devices is demonstrated. Utilizing knowledge gained from temperature measurements in boilers, and the situation regarding the slagging of heating surfaces located at the outlet from the furnace, new, frequently higher values are proposed. A method for evaluating the allowable gas temperature at the outlet froma furnace subject to slagging is suggested on the basis of data regarding the chemical composition of the mineral portion of coals. __________ Translated from élektricheskie Stantsii, No. 2, February, 2007, pp. 23–28.     

车载导航系统USB数据下载的设计与实现

为了提高车载导航系统中文件下载的速度,提出了给系统增加USB接口的设计方法。对总体设计进行了概述,并分别给出了系统的硬件设计及固件程序和应用程序设计。测试结果证明USB给车载导航系统提供了一种可靠、高效的文件传输方式。     

胡萝卜酒发酵工艺的条件优化

用正交试验的极差、方差分析方法对胡萝卜酒发酵工艺条件进行了优化。结果表明，采用葡萄酒活性干酵母，将菌种扩大11倍，于25℃发酵5d，可得到酒精度13％(v／v)，果香浓郁、醇厚、清澈明亮、口味纯正的优质胡萝卜酒。