基于Wi-Fi Direct的道路交通状态信息采集方法

针对传统交通状态信息采集中采用的环形线圈车辆检测器存在布设和维护难度较大等问题,提出了一种基于Wi-Fi Direct的道路交通状态信息采集方法,以实现对基本的道路交通流状态参数进行采集估计;该方法利用车-路通讯设备实现车辆与路侧设备的通信;以车载通讯设备的Wi-Fi芯片介质访问控制层地址完成车辆个体识别;通过车载通讯设备中的北斗定位装置向路侧设备提供车辆实时位置及时间信息,进而实现道路区段内交通流基本状态信息估计;实验测试表明,该方法能够完成路段平均速度、交通流量及车流密度的采集和估计,是一种有效的道路交通信息采集方法。

Enhancement of the thermostability of β-1,3-1,4-glucanase by directed evolution

In order to improve the thermostability of β- 1,3-1,4-glucanase, evolutionary molecular engineering was used to evolve the β-1,3-1,4-glucanase from Bacillus subtilis ZJF-1A5. The process involves random mutation by error-prone PCR and DNA shuffling followed by screening on the filter-based assay. Two mutants, EGsl and EGs2, were found to have four and five amino acid substitutions, respectively. These substitutions resulted in an increase in melting temperature from Tm=62.5℃ for the wild-type enzyme to Tm=65.5℃ for the mutant EGsl and 67.5℃ for the mutant EGs2. However, the two mutated enzymes had opposite approaches to produce reducing sugar from lichenin with either much higher （28%） for the former or much lower （21.6%） for the latter in comparison with their parental enzymes. The results demonstrate that directed evolution is an effective approach to improve the thermostability of a mesophilic enzyme.

Effects on coagulation factor production following primary hepatomitogen-induced direct hyperplasia

AIM： To investigate the molecular mechanisms involved in coagulation factor expression and/or function during direct hyperplasia （DH）-mediated liver regeneration. METHODS： Direct hyperplasia-mediated liver regeneration was induced in female C57BL/6 mice by administering 1,4-bisr2-（3,5-dichloropyridyloxy）] benzene （TCPOBOP）, a representative hepatomitogen. Mice were weighed and sacrificed at various time points [Day 0 （D0： prior to injection）, 3 h, D1, D2, D3, and D10] after TCPOBOP administration to obtain liver and blood samples. Using the RNA samples extracted from the liver, a comprehensive analysis was performed on the hepatic gene expression profiling of coagulation-related factors by real-time RT-PCR （fibrinogen, prothrombin, factors Ⅴ, Ⅶ, Ⅷ, Ⅸ, Ⅹ, Ⅺ, Ⅻ, ⅩⅢβ , plasminogen, antithrombin, protein C, protein S, ADAMTS13, and VWF）. The corresponding plasma levels of coagulation factors （fibrinogen, prothrombin, factors Ⅴ, Ⅶ, Ⅷ, Ⅸ, Ⅹ, Ⅺ, Ⅻ, ⅩⅢ, and VWF） were also analyzed and compared with their mRNA levels. RESULTS： Gavage administration of TCPOBOP （3 mg/kg body weight） resulted in a marked and gradual increase in the weight of the mouse livers relative to the total body weight to 220% by D10 relative to the DO （control） ratios. At the peak of liver regeneration （D1 and D2）, the gene expression levels for most of the coagulationrelated factors （fibrinogen, prothrombin, factors Ⅴ, Ⅶ, Ⅷ, Ⅸ,Ⅺ, Ⅻ, ⅩⅢβ, plasminogen, antithrombin, protein C, ADAMTS13, VWF） were found to be downregulated in a time-dependent manner, and gradually recovered by D10 to the basal levels. Only mRNA levels of factor X and protein S failed to show any decrease during the regenerative phase. As for the plasma levels, 5 clotting factors （prothrombin, factors Ⅷ, Ⅸ, Ⅺ, and Ⅻ） demonstrated a significant decrease （P 〈 0.05） during the regeneration phase compared with DO. Among these 5 factors, factor Ⅸ and factor Ⅺ showed the most dramatic decline in their activities by about 50% at D2 compared to the basal levels, and these reductions in plasma activity for both factors were consistent with our RT-PCR findings. In contrast, the plasma activities of the other coagulation factors （fibrinogen, factors Ⅴ, Ⅶ, ⅩⅢ, and VWF） were not significantly reduced, despite the reduction in the liver mRNA levels. Unlike the other factors, FX showed a temporal increase in its plasma activity, with significant increases （P 〈 0.05） detected at DI. CONCLUSION： Investigating the coagulation cascade protein profiles during liver regeneration by DH may help to better understand the basic biology of the liver under normal and pathological conditions.

La_(0.75)Sr_(0.25)Cr_(0.5)Mn_(0.5)O_(3)-δ−Ce_(0.8)Gd_(0.2)O_(1.9) composite electrodes as anodes in LaGaO_(3)-based direct carbon solid oxide fuel cells

Direct carbon solid oxide fuel cells(DC-SOFCs)are promising,green,and efficient power-generating devices that are fueled by solid carbons and comprise all-solid-state structures.Developing suitable anode materials for DC-SOFCs is a substantial scientific challenge.Herein we investigated the use of La_(0.75)Sr_(0.25)Cr_(0.5)Mn_(0.5)O_(3)-δ−Ce_(0.8)Gd_(0.2)O_(1.9)(LSCM−GDC)composite electrodes as anodes for La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(3)-δelectrolyte-based DC-SOFCs,with Camellia oleifera shell char as the carbon fuel.The LSCM−GDC-anode DC-SOFC delivered a maximum power density of 221 mW/cm^(2) at 800℃ and it significantly improved to 425 mW/cm^(2) after Ni nanoparticles were introduced into the LSCM−GDC anode through wet impregnation.The microstructures of the prepared anodes were characterized,and the stability of the anode in a DC-SOFC and the influence of catalytic activity on open circuit voltage were studied.The above results indicate that LSCM–GDC anode is promising to be applied in DC-SOFCs.

Differential interformational velocity analysis as an effective direct hydrocarbon indicator under velocity reversal conditions,an example from the anomalously high temperature and over-pressured DF1-1 Gas Field in the Yinggehai Basin,South China Sea

In the DF1-1 Gas Field in the Yinggehai Basin, South China Sea, the velocity-depth plot and velocity spectra show significant variations from a linear trend, exhibiting a distinct reversal phenomenon. Velocity parameters derived from velocity spectral analysis of the seismic data and sonic logs indicate that the interval velocity reverses below 2,100 m (2.2 s two-way time (TWT)) in the DF1-1 Gas Field. Some direct hydrocarbon indicators (DHIs) models developed for the shallow strata cannot be simply applied to the moderately to deeply buried strata for direct exploration target recognition because the velocity reversal has caused the middle-deep gas reservoirs to exhibit a moderate or weak seismic amplitude. The hydrocarbon indicator method of “Differential Interformational Velocity Analysis (DIVA)” with the aid of other hydrocarbon indicating techniques was employed to effectively identify DHIs in the middle-deep strata under velocity inversion. The result has shown that the DIVA technique can be effectively used as a DHI in both the shallow and the middle-deep strata in the study area with the shallow strata characterized by Type I DIVA anomaly and the middle-deep strata characterized by the Type II DIVA anomaly.

DICP Symposium (I) on Catalysis: Future Directions of Catalysis Science and Technology October 16-18, 2003, Dalian, China

Introduction and Invitation DICP Symposium is a special series of interna-tional conference named after the Dalian Instituteof Chemical Physics (DICP). The DICP Symposiumwas founded with the purpose to promote the interna-tional communication and collaboration between theDICP and the international scientific community, to

DFT Study on the (S)-Proline-catalyzed Direct Aldol Reaction between Acetone and 4-Nitrobenzaldehyde

DFT/6-31G^＊ calculations were applied to study the direct aldol reaction between acetone and 4-nitrobenzaldehyde catalyzed by （S）-proline. Four transition states associated with the stereo-controlling step, corresponding to syn and anti arrangements of methylene moiety related to the carboxylic acid group in enamine intermediate and re and si attacks to the aldehyde carbonyl carbon have been obtained. The solvent effect of DMSO was investigated with polarized continuum model. The computed energies of transition states reveal the stereo-selectivity of the reaction.

The Forming Conditions of and Ore-searching Direction for B, Mg,Pb, Zn and Au Deposits in the Liaoji Proterozoic Rift

The Liaoji Proterozoic rift is an inter-intracontinenatl rift developed from Archean granite-greenstone tectonic regime and contains many important mineral deposits of U, B, magnesite, Pb-Zn, Au, Ag, Co and P. These deposits were formed as the result of late mobilization, transportation and concentfation of the previously enriched ore-forming mate- rials in several ore-bearing formations formed during the rift stage. So the metallogeny of these deposits in the rift shows both inheritance and new generation of the ore-forming materials. In future ore-searching practice, attentions should be paid on the studies of the ore-bearing formations in the rift, on the multiple stages of metallogeny and and on multiple derivations of the ore-forming materials.

Enantio-selective preparation of (S)-1-phenylethanol by a novel marine GDSL lipase MT6 with reverse stereo-selectivity

We previously functionally characterized a novel marine microbial GDSL lipase MT6 and identified that the stereo-selectivity of MT6 was opposite to that of other common lipases in trans-esterification reactions.Herein,we have investigated the use of MT6 in stereo-selective biocatalysis through direct hydrolysis reactions.Notably,the stereo-selectivity of MT6 was also demonstrated to be opposite to that of other common lipases in hydrolysis reactions.Parameters,including temperature,organic co-solvents,pH,ionic strength,catalyst loading,substrate concentration,and reaction time,affecting the enzymatic resolution of racemic 1-phenylethyl acetate were further investigated,with the e.e.of the final（S）-l-Phenylethanol product and the conversion being 97%and 28.5%,respectively,after process optimization.The lengths of side chains of 1-phenylethyl esters greatly affected the stereo-selectivity and conversion during kinetic resolutions.MT6 is a novel marine microbial GDSL lipase exhibiting opposite stereo-selectivities than other common lipases in both trans-esterification reactions and hydrolysis reactions.

Where is the rudder of a fish?:the mechanism of swimming and control of self-propelled fish school

Numerical simulation and control of self- propelled swimming of two- and three-dimensional biomimetic fish school in a viscous flow are investigated. With a parallel computational fluid dynamics package for the two- and three-dimensional moving boundary problem, which combines the adaptive multi-grid finite volume method and the methods of immersed boundary and volume of fluid, it is found that due to the interactions of vortices in the wakes, without proper control, a fish school swim with a given flap- ping rule can not keep the fixed shape of a queue. In order to understand the secret of fish swimming, a new feedback con- trol strategy of fish motion is proposed for the first time, i,e., the locomotion speed is adjusted by the flapping frequency of the caudal, and the direction of swimming is controlled by the swinging of the head of a fish. Results show that with this feedback control strategy, a fish school can keep the good order of a queue in cruising, turning or swimming around circles. This new control strategy, which separates the speed control and direction control, is important in the construction of biomimetic robot fish, with which it greatly simplifies the control devices of a biomimetic robot fish.

Numerical simulation of flow separation over a backward-facing step with high Reynolds number

Large eddy simulation (LES) explicitly calculates the large-scale vortex field and parameterizes the small-scale vortices.In this study,LES and κ-ε models were developed for a specific geometrical configuration of backward-facing step (BFS).The simulation results were validated with particle image velocimetry (PIV) measurements and direct numerical simulation (DNS).This LES simulation was carried out with a Reynolds number of 9000 in a pressurized water tunnel with an expansion ratio of 2.00.The results indicate that the LES model can reveal largescale vortex motion although with a larger grid-cell size.However,the LES model tends to overestimate the top wall separation and the Reynolds stress components for the BFS flow simulation without a sufficiently fine grid.Overall,LES is a potential tool for simulating separated flow controlled by large-scale vortices.

Direct modeling for computational fluid dynamics

All fluid dynamic equations are valid under their modeling scales, such as the particle mean free path and mean collision time scale of the Boltzmann equation and the hydrodynamic scale of the Navier-Stokes （NS） equations. The current computational fluid dynamics （CFD） focuses on the numerical solution of partial differential equations （PDEs）, and its aim is to get the accurate solution of these governing equations. Under such a CFD practice, it is hard to develop a unified scheme that covers flow physics from kinetic to hydrodynamic scales continuously because there is no such governing equation which could make a smooth transition from the Boltzmann to the NS modeling. The study of fluid dynamics needs to go beyond the traditional numer- ical partial differential equations. The emerging engineering applications, such as air-vehicle design for near-space flight and flow and heat transfer in micro-devices, do require fur- ther expansion of the concept of gas dynamics to a larger domain of physical reality, rather than the traditional dis- tinguishable governing equations. At the current stage, the non-equilibrium flow physics has not yet been well explored or clearly understood due to the lack of appropriate tools. Unfortunately, under the current numerical PDE approach, it is hard to develop such a meaningful tool due to the absence of valid PDEs. In order to construct multiscale and multiphysics simulation methods similar to the modeling process of con- structing the Boltzmann or the NS governing equations, the development of a numerical algorithm should be based on the first principle of physical modeling. In this paper, instead of following the traditional numerical PDE path, we introduce direct modeling as a principle for CFD algorithm develop- ment. Since all computations are conducted in a discretized space with limited cell resolution, the flow physics to be mod- eled has to be done in the mesh size and time step scales. Here, the CFD is more or less a direct construction of dis- crete numerical evolution equations, where the mesh size and time step will play dynamic roles in the modeling process. With the variation of the ratio between mesh size and local particle mean free path, the scheme will capture flow physics from the kinetic particle transport and collision to the hydro- dynamic wave propagation. Based on the direct modeling, a continuous dynamics of flow motion will be captured in the unified gas-kinetic scheme. This scheme can be faithfully used to study the unexplored non-equilibrium flow physics in the transition regime.

气象观测场在汽车试验场中的应用研究

汽车试验场作为汽车开展道路测试的重要场所,用于验证汽车产品的品质以及可靠性。除了场地道路外,气象条件作为汽车道路测试的重要一环,在《GB/T12534-1990汽车道路试验方法通则》中也有明确要求,如:试验时应是无雨无雾天气,相对湿度小于95%,气温0-40℃,风速不大于3m/s。同时气象条件也作为试验场道路管控的重要依据,实时风速、雨量、能见度等信息为场地管理者发布限速、限行、封场等通知提供必要参考依据,直接影响道路测试安全管控的及时性。因此,文章从气象观测场的建设、气象服务、异常天气道路管控等方面开展气象观测场在汽车试验场中的应用研究。

LOCATIONAL DISTRIBUTION AND SPATIAL DIFFUSION OF FOREIGN DIRECT INVESTMENTS FROM HONGKONG AND MACAO IN MAINLAND OF CHINA

Foreign direct investments (or FDIs) have been employed since the early 1980s and they have become more and more immportant in Chinese economic development. However, the roles of FDIs are very different between regions, partly due to the different locational preference of various source countries. Some facts show that FDIs from Hongkong - Macao indicate a strong locational preference. Therefore, this paper attempts to make an empirical research on the locational preference of Hongkong - Macao’s FDIs and their spatial diffusion under the support of statistical data with regrereion analysis. In this paper, three statistical models, including the special location model, the general location model and the spatial diffusion model, are created. The results show that this kind of analysis is successful. The major conclusions are as follows. (1) The optimum location for FDIs from Hongkong - Macao lies in the coastal area, especially Guangdong, Hainan, Jiangsu, Shandong, Fujian provinces. Besides, Hubei Province is also an important radon. (2) The FDIs from HongkongMacao in China have diffused gradually from the coastal provinces to the inland regions, the northem and the metropolis and from the locations that had attracted a large number of investments to their vicinities since the 1990s. (3) The special location factors, such as the herder effect, the unique social and kinship ties are the key factors determining the special locational distribution. (4) The general location and spatial diffusion of Hongkong - Macao’s FDIs are the results of interplay of several economic factors. They are the economic scale and advantage, the growth rate, the laier force and economic extrovert etc.

意义概念的三个模型

弗雷格首先把意义概念引入分析哲学,其真正目的是坚持思想有公认的确定的正确与错误之分,为思想的客观分析提供基础,但其借助的意义即思想的实体化却有违于这个初衷。直接经验论者从直接经验论立场出发,企图在经验世界中找意义,最后走向否定意义本身,分析哲学由此遭到重创。从语言、思想、世界的关系的高度,把弗雷格的意义理论、观念论、用法论的合理精神结合起来,构建了语境—思想意义模型,认为语言的意义既是主观的东西,同时又具有特殊的客观性:由公共客观的语境决定的确定性。语言的意义就是特定语境中的语言所表达的人们的思想。

The effects of fabrication atmosphere condition on the microstructural and mechanical properties of laser direct manufactured stainless steel 17-4 PH

The effects of atmosphere conditions on microstructural and mechanical properties of stainless steel 17-4PH components fabricated by laser direct manufacturing (LDM) were investigated through mea-surements on phase constitution, porosity, tensile strength, fracture morphology, hardness and evolution of substrate temperature. Results showed that the samples produced in air atmosphere condition pos-sessed higher tensile strength and hardness for both as-deposited and heat-treated states than that in Ar chamber condition, due to dispersion strengthening effect of amorphous oxide particles and nitrogen solution strengthening as a result of higher content of oxygen and nitrogen. The temperature of substrate heat accumulation was higher in Ar chamber condition, leading to dramatically lower porosity and more reverse austenite, which also contributed to the lower strength and hardness.

Nanoparticle nucleation and coagulation in a mixing layer

Numerical simulation of nanoparticle nucleation and coagulation in a mixing layer with sulfuric acid vapor binary system is performed using the large eddy simulation and the direct quadrature method of moment. The distributions of number concentration, volume concentration, and average diameter of nanoparticles are obtained. The results show that the coherent structures have an important effect on the distributions of number concentration, volume concentration and average diameter of nanoparticles via continuously transporting and diffusing the nanoparticles to the area of low particle concentration. In the streamwise direction, the number concentration of nanoparticles decreases, while the volume concentration and the average diameter increase. The distributions of number concentration, volume concentration and average diameter of nanoparticles are spatially inhomogeneous. The characteristic time of nucleation is shorter than that of coagulation. The nucleation takes place more easily in the area of low temperature because where the number concentration of nanoparticles is high, while the intensity of coagulation is mainly affected by the number concentration. Both nucleation and coagulation result in the variation of average diameter of nanoparticles.

Size distribution,directional source contributions and pollution status of PM from Chengdu,China during a long-term sampling campaign

Long-term and synchronous monitoring of PMIo and PM2.s was conducted in Chengdu in China from 2007 to 2013. The levels, variations, compositions and size distributions were investigated. The sources were quantified by two-way and three-way receptor models （PMF2, ME2-2way and ME2-3way）, Consistent results were found： the primary source categories contributed 63.4% （PMF2）, 64.8% （ME2-2way） and 66.8% （ME2-Bway） to PMIo, and contributed 60.9% （PMF2）, 65.5% （ME2-2way） and 61.0% （ME2-3way） to PM2.s. Secondary sources contributed 31.8% （PMF2）, 32.9% （ME2-2way） and 31.7% （ME2-3way） to PMIo, and 35.0% （PMF2）, 33.8% （ME2-2way） and 36.0% （ME2-3way） to PM2.s. The size distribution of source categories was estimated better by the ME2-3way method. The three-way model can simultaneously consider chemical species, temporal variability and PM sizes, while a two-way model independently computes datasets of different sizes. A method called source directional apportionment （SDA） was employed to quantify the contributions from various directions for each source category. Crustal dust from east-north-east （ENE） contributed the highest to both PM^o （12.7%） and PMzs （9.7%） in Chengdu, followed by the crustal dust from south-east （SE） for PMao （9.8%） and secondary nitrate ＆ secondary organic carbon from ENE for PMzs （9.6%）. Source contributions from different directions are associated with meteorological conditions, source locations and emission patterns during the sampling period. These findings and methods provide useful tools to better understand PM pollution status and tn dovolon offoctive nolhltion control gtrateMeg.

Novel AC Servo Rotating and Linear Composite Driving Device for Plastic Forming Equipment

The existing plastic forming equipment are mostly driven by traditional AC motors with long trans- mission chains, low efficiency, large size, low precision and poor dynamic response are the common disadvantages. In order to realize high performance forming processes, the driving device should be improved, especially for com- plicated processing motions. Based on electric servo direct drive technology, a novel AC servo rotating and linear composite driving device is proposed, which features implementing both spindle rotation and feed motion with- out transmission, so that compact structure and precise control can be achieved. Flux switching topology is employed in the rotating drive component for strong robustness, and fractional slot is employed in the linear direct drive component for large force capability. Then the mechanical structure for compositing rotation and linear motion is designed. A device prototype is manufactured, machining of each component and the whole assembly are presented respectively. Commercial servo amplifiers are utilized to construct the control system of the proposed device. To validate the effectiveness of the proposed composite driving device, experimental study on thedynamic test benches are conducted. The results indicate that the output torque can attain to 420 N-m and the dynamic tracking errors are less than about 0.3 rad in the rotating drive, the dynamic tracking errors are less than about 1.6 mm in the linear feed. The proposed research provides a method to construct high efficiency and accu- racy direct driving device in plastic forming equipment.

DFT Study on the Origin of the Enantioselectivity of （S）-4-Hydroxylproline-Catalyzed Direct Aldol Reaction between Acetone and 4-Nitrobenzaldehyde

DFT-B3LYP calculations were carried out to study the enantioselectivity of the （S）-4-hydroxylproline-catalyzed direct aldol reaction between acetone and 4-nitrobenzaldehyde. Four transition structures associated with the stereo-controlling step of the reaction have been determined. They are corresponding to the anti and syn arrangements of the methylene moiety related to the carboxylic acid group in enamine intermediate and the si and re attacks to the aldehyde carbonyl carbon. The effect of DMSO solvent on the stereo-controlling step was investigated with polarized continuum model （PCM）. The computed energies of the transition states reveal the moderate enantioselectivity of the reaction.