如何运用“三平台、一机制”加强班组安全建设

从班组安全建设的重要性出发,介绍了"三平台、一机制"安全管理模式的创建背景、内涵,并以大唐国际北京高井热电厂的实践为例,提出了"三平台、一机制"安全管理模式的具体实施方法。

OBE教育理念下的操作系统课程教学实践

本文主要探讨了成果导向教育(OBE)在操作系统课程中的应用。在课程教学中具体采用“四环节”和“一机制”策略,包括设定明确学习成果、更新教学内容、重新设计教学方案和完善评估体系,以及引入一系列持续改进机制,如定期培训和反馈收集,这些措施旨在提高教学质量,提升学生的应用能力。

多维协同构建计算机类专业人才实践与创新能力培养体系

依托多维协同改革思路,紧密跟踪计算机学科发展前沿,顺应人才培养教育的时代需求,构建了"行业协同、校企协同、科教协同、学科交叉"的计算机类专业人才实践与创新能力培养模式,利用教学云平台将六个实践与创新能力培养平台整合为一体,并通过专业基础型、综合设计型、研究创新型三个层次的教学来提升学生实践与创新能力,构建了一套能力评估与质量监控机制,形成了"三层次六平台一机制"的实践与创新能力培养体系,着力培养"适应能力强、实干精神强、创新意识强"的计算机类新型"三强人才"。

An Experimental Study of Pathogenesis of Steroid-induced Avascular Necrosis of Femoral Head

Objective: To explore the pathogenesis of avascular necrosis of femoral head(ANFH) and search an effective method for clinical practice. Methods: Twenty-four Japanese rabbitswere divided into 2 groups of models and controls. ANFH models were produced byintramuscular-injection of large dosage of steroid to rabbits for 8 weeks. From the 4th, 8th and12th week after production of models, 2 rabbits of each group were sacrificed to observe thestructure of femoral head through light microscope and scanning electron microscope. The contents ofNitric Oxide (NO), tissue-type plasminogen activator (t-PA) and -plasminogen activator inhibitor(PAI) in plasma of the 4 rabbits in each group were estimated at the same time. Results: Comparedwith control group, the rabbits of model group exhibited many differences: such as osteoporosis offemoral head, the presence of more bone lacuna and fat cell through light microscope observing; thebroken and sunk bone trabecula, the loosen and broken collagen fibers on the surface of bone matrixthrough scanning electron microscope observing. Compared with control group, the Concentration ofNO and t-PA in plasma of the model rabbits decreased obviously, but the Concentration of the PAIincreased obviously. Conclusion: The steroid-induced ANFH might be related to the lower level of NOand the descent of fibrinolytic activity.

Differential Expression of PKC Isoforms and Their Tumoricidal Activity in Two Macrophage Cell Lines: Involvement of Nitric Oxide-dependent Mechanisms

Objective: To investigate the role of PKC isoforms in the regulation of LPS-triggered tumoricidal activity in macrophages and further elucidate its signal mechanisms. Methods: Two macrophage cell lines (P388D1 and RAW264.7) were stimulated by LPS alone, or with long-term of PMA pretreatment. Then cytotoxicities to P815 cells (by MTT assay) and IL-1, TNF- (by ELISA) and nitric oxide (NO) production (by Griess reagent) in supernatants were measured. Western blot for PKC isoforms after long-term PMA pretreatment was analyzed. Results: RAW264.7 cells were stimulated with LPS to kill target tumor cells P815, whereas P388D1 cells failed to develop such an ability. Down-regulation of PKC isoforms by chronic treatment with PMA significantly inhibited the LPS-induced cytotoxicity in RAW264.7 cells. In unstimulated state, Western blotting with rabbit antiserum specific for the PKC, 1, 2, or showed all 5 isoforms were detected in P388D1 cells, while only PKC, PKC1 and PKC were detected in RAW264.7 cells. Exposure of the cells to long-term of PMA treatment significantly down-regulated the expression of PKC, PKC1 and PKC in RAW264.7 cells. But in P388D1 cells, although PKC, PKC and PKC were down-regulated, the expression of PKC1 and PKC2 could not be regulated. Comparing with LPS-induced IL-1, TNF- and NO production by the two macrophage cell lines, P388D1 failed to produce NO. In RAW264.7 cells, LPS-induced NO production and antitumor activity was attenuated by the addition of L-NAME, an iNOS inhibitor. Conclusion: The results indicated a critical role of PKC in LPS-induced antitumor activity and this cytotoxicity is mainly due to PKC- mediated NO production by RAW264.7 cells, but not a direct cytotoxic activity.

Effect of cooling rate on morphology of primary particles in Al-Sc-Zr master alloy

Al-1.0%Sc-1.0%Zr （mass fraction） master alloy was prepared at different cooling rates. The morphology and thermodynamics data of the primary particles of the master alloy were investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and differential scanning calorimetry （DSC）. It shows that the primary particles are dendrite-shaped particles comprised of several attached small cubic, cusped-cubic or crucifer shape particles at slow cooling rate. However, the primary particles are separated with crucifer shape at intermediate cooling rate, and they are cubic with cusped-cubic shape at high cooling rate. Meanwhile, the separated and attached particles present AlaSc/AlaZr1-xScx core-shell structure. The formation mechanism of the structure was systematically investigated by a mathematical model.

Impact of Continuous Chinese Fir Monoculture on Soil

Soil properties were investigated in sites where three succeeding generationsof Chinese fir (Gunning-hamia lanceolata, (Lambert) Hooker) in Nanping, Fujian, China, werecultivated in order to show the impact of a repeated monoculture on site productivity. Compared withthe first generation (FG) stand the soil structure deteriorated in the second generation (SG) andthe third generation (TG) stands. For instance, the destruction rate of the peds increased by 55%-115% in the SG and the TG stands compared to the FG stand. Soil nutrient storage and nutrientavailability also decreased in the SG and the TG stands. For surface soils of 0-20 cm, the organicmatter content, total N and P, and available N and P decreased by 3%-20% relative to those in the FGstand. For many soil parameters, the differences between the FG stand and the SG and the TG standswere statistically significant (LSD test, P < 0.05). Furthermore, with each succeeding generation ofChinese fir, the total number of soil microbes declined, the soil enzyme activity weakened, and thesoil biological activity decreased. In order to maintain sustainable site productivity, newsilvicultural practices need to be developed for management of Chinese fir plantations.

CHANGES OF NITRIC OXIDE AND PROTECTIVE EFFECTS OF NITRIC OXIDE INHIBITORS IN NEWBORN RATS WITH SEPSIS

In a newborn rat model of sepsis, the changes of nitric oxide and the protective effects of methylene blue orland dexamethason were investigated. The results revealed that plasma nitric oxide levels were elevated at 6 h and peaked at 12 h after bacterial challenge. The treatment with methylene or/and dexamethasone was found to blunt hypoglycemia and hyperlacticemia, to reduce the occurrence rate of loss of response to pain, and to prolong the survival time. Moreover, therapy by dexamethasone was shown to decrease the 24 h mortality. The results suggested that nitric oxide play an important role during the course of fatal P. aeruginosa sepsis, but it is clear that the clinical value of nitric oxide and its inhibitors need to be further studied.

EVIDENCE OF INCREASED ENDOGENOUS CARBON MONOXIDE PRODUCTION IN NEWBORN RAT ENDOTOXICOSIS

Carbon monoxide is thought to serve as a new endogenous mediator in the pathogenesis of sepsis andseptic shock. In newborn rat endotoxicosis, carbon monoxide levels in the circulation as well as liver, kid-ney and lung were found to be significantly increased (P<0. 05). Moreover, the elevations of carbonmonoxide correlated with enhanced nitric oxide production as indicated by nitrite/nitrate levels (P<0. 05).Our present data showed for the first time that endogenously produced carbon monoxide was increasedduring the course of shock-like states, which suggested that the role of carbon monoxide in sepsis and sep-tic shock might worth further study.

Robotics and mechatronics for planetary surface exploration

The paper briefly addresses DLR' s ( German Aerospace Center) expertise in space robotics by handof corresponding milestone projects including systems on the International Space Station ISS. It then discussesthe key technologies needed for the development of an artificial "robonaut" generation with mechatronic ultra-light weight arms and multifingered hands. The third arm generation is nearly finished now, approaching thelimits of what is technologically achievable today with respect to light-weight and power losses. In a similar wayDLR' s second generation of artificial 4-fingered hands was a big step towards higher reliability, manipulabilityand overall performance.

System design of a dexterous lightweight robot arm with remote control

This paper presents a novel remote controlled dexterous robot arm with 6 degrees of freedom （DOF）. As a highly integrated mechatronics system, sensors and their signal processing system are integrated inside each joint. To lighten the weight, almost all mechanical parts are made of aluminum and the robot control system is placed outside. The modular concept is adopted during the robot design process for time and cost saving. Considering the much greater torque acted on the two shoulder joints, the joint shells are strengthened in the design to increase joint stiffness and suppress system vibration. Meanwhile, to simplify the maintenance, a new spring pins electronic connector is designed to disassemble every joint, connector and link independently without cutting any cables. The teleoperation technology enables the robot to offer more convenient service definitely for people＇ s daily life. Virtual reality technology is used to solve the time delay problem during teleoperation. Finally, two typical daily chore experiments are implemented to prove the manipulation ability of the dexterous robot arm.

In-Pipe Mobile Minimachine and Its Control

This paper deals with utilization possibility of a kinematical couple of screw-matrix in minimachine mechatronic concept which is assigned to move within the pipes having less than 25 mm of the inner diameter. The principle of the movement for a straightforward motion consists in transformation of the actuator rotary movement through a screw and a nut to the linear motion. It causes a change of distance between the front and rear parts of the minimachine modules. Due to minimization of the dimensions, the electrical control and power supply components are placed outside of the minimachine operating area. The control module is based on a programmable integrated circuit （PIC）.

Research on Flexible Manufacturing System in Mechatronics Professional Comprehensive Training

According to the characteristics of flexible manufacturing systems, the article describes the equipment components and hardware architecture of flexible manufacturing systems in school. Taking welding assemble process as an example to elaborate production process automation, the paper put forward a flexible manufacaxring system combined with laboratory equipment and various grades, professional knowledge and teaching characteristics and differentiated teaching programs, the creation of the laboratory project was planned and implemented to specific engineering training programs, so that students has been expanded in the depth of expertise and breadth, experimental skills and innovation capacity has been improved, the teaching effect has also been significantly improved..

守好社区疫情联防联控第一线

社区是疫情联防联控的第一线,也是外防输入、内防扩散最有效的防线。把社区这道防线守住,就能有效切断疫情扩散蔓延的渠道。按照习近平总书记指示要求,北京市平谷区紧紧抓住社区(村)这一基础阵地,抓好疫情防控,探索推进基层组织建设和基层治理体系建设,健全完善基层组织体系、制度体系和工作机制,逐步完善基层治理体系,有效提升疫情防控水平,切实增强基层执政能力。

Camera Calibration with 1D Rotating Objects

In this paper,we use 1D rotating objects to calibrate camera.The calibration object has three collinear points.It is not necessary for the object to rotate around one of its endpoints as before;instead,it rotates around the middle point in a plane.In this instance,we can use two calibration constraints to compute the intrinsic parameters of a camera.In addition,when the 1D object moves in a plane randomly,the proposed technique remains valid to compute the intrinsic parameters of a camera.Experiments with simulated data as well as with real images show that our technique is accurate and robust.

Consensus-based three-dimensional multi-UAV formation control strategy with high precision

We propose a formation control strategy for multiple unmanned aerial vehicles （multi-UAV） based on second-order consensus, by introducing position and velocity coordination variables through neighbor-to-neighbor interaction to generate steering commands. A cooperative guidance algorithm and a cooperative control algorithm are proposed together to maintain a specified geometric configuration, managing the position and attitude respectively. With the whole system composed of the six-degree-of-freedom UAV model, tile cooperative guidance algorithm, and the cooperative control algorithm, the formation control strategy is a closed-loop one and with full states. The cooperative guidance law is a second-order consensus algorithm, providing the desired acceleration, pitch rate, and heading rate. Longitudinal and lateral motions are jointly considered, and the cooperative control law is designed by deducing state equations. Closed-loop stability of the formation is analyzed, and a necessary and sufficient condition is provided. Measurement errors in position data are suppressed by synchronization technology to improve the control precision. In the simulation, three-dimensional formation flight demonstrates the feasibility and effectiveness of the formation control strategy.

Study on Nitrous Oxide Emission in Boiler Furnace

A theoretical investigation on a kinetic mechanism of nitrous oxide formation in flames with different fuels was carried out for purposes of minimizing the total NOx yield. The effect of fuel type and combustion condition on N2O emission is discussed. It is found that N2O constitutes a relatively small fraction of the total NOx formation, but it is of great importance to both No formation and NO reduction from fuel nitrogen (N1) and molecular nitrogen (N2).

Understanding formation mechanism of ZnO diatomic chain and multi-shell structure using physical mechanics:Molecular dynamics and first-principle simulations

In this paper,the possibility of the monatomic chain (MC) formation for ZnO material was studied by molecular dynamics (MD) simulation.The process of MC formation and the effects of temperature,strain rate and size were studied extensively.The tensile process can be divided to be five stages and the ZnO diatomic chain (DC) can be found.The MD results show that most atoms in MC came from the original surface of ZnO nanowires (NWs).Temperature and strain rate are two important factors affecting the process,and both high temperature and low strain rate in a certain range would be beneficial to the formation of DC.Moreover,the effects of strain rate and temperature could attribute to the Arrhenius model and the energy release mechanism.Furthermore,multi-shell structure was found for the samples under tensile strain and the layer-layer distance was about 3.Our studies based on density functional theory showed that the most stable structure of ZnO DC was confirmed to be linear,and the I-V curve was also got using ATK.

Working Mechanism of a BC_3 Nanotube Carbon Monoxide Gas Sensor

Carbon and BN nanotubes have previously demonstrated extreme sensitivity to several molecules, but they cannot be used to detect highly toxic molecules of CO. In this work, we examine the possibility of a BC3 nanotube (BC3NT) as a potential gas sensor for CO detection by using density functional theory calculations. It is found that CO molecule can be absorbed on B and C atoms of BC3 NT wall with adsorption energies in the range of 1.0 to 25.9 kcal/mol and it can donate finite charge to the tube. By comparing the HOMO/LUMO energy gaps of the bare and CO adsorbed nanotubes, we deduce that molecular CO can induce significant change in the electrical conductivity of the tube. The conductivity change can generate an electrical signal, which might be useful for CO detection.

China＇s Approach to Its Exchange Rate Mechanism： Adaptability of BBC Rules

China＇s recent declaration of principles on its exchange rate mechanism has made it very clear that any move should be on China＇s own initiative; such a move should be sustainable and under control. China has adopted gradualism in the exchange rate reform process. On July 21st, 2005, China changed Renminbi （RMB） pariy （appreciation） by 2 percent, signaling the exchange market reform process. This paper is to study the past history of the crawling-peg of RMB on the US dollar with a view of its future reform. The flexibility provided by the crawling-peg still fits well with China＇s status quo. However, the flexible mechanism should follow the trend of China＇s economic development with well-timed parity changes. The extent of the fluctuation band rests upon China＇s ability to maintain its currency stability to counter future speculation and shocks. Only when the market mechanism is restored in China can an equilibrium RMB exchange rate be reached.