基于STM32输液器验气系统设计

针对当前人工检测输液器效率低下、质量检测水平不高等情况,设计开发了一种基于STM32单片机的输液器验气系统。该系统主要包括硬件及软件系统两个部分,其中以STM32F103单片机为硬件系统核心,针对气体压力传感器采集电路以及对多路电磁阀控制电路进行设计;系统软件设计采用C++实时操作系统,确保检测系统的实时性和有效性;检测数据通过USB串口通讯传送到上位机并显示。实验证明:输液器验气系统可对输液器进行验气检测,该系统具有稳定性、精度较高等特点,实验测量相对误差在±5%范围之内,检测效率高于人工检测。

A Smog Chamber Facility for Qualitative and Quantitative Study on Atmospheric Chemistry and Secondary Organic Aerosol

In order to investigate the atmospheric oxidation processes and the formation of secondary organic aerosol （SOA）, an indoor environmental reaction smog chamber are constructed and characterized. The system consists of the collapsible ～830 L FEP Teflon film main reactor, in which the atmospheric chemical reactions take place and the formation of SOA occurs under the simulated atmospheric conditions, and the diverse on-line gas- and particle-phase instrumentation, such as the proton transfer reaction mass spectrometer, the synchrotron radiation photoionization mass spectrometer, the aerosol laser time-of-flight mass spectrometer, and other traditional commercial instruments. The initial characterization experiments are described, concerning the temperature and ultraviolet light intensity, the reactivity of the pure air, the wall loss rates of gaseous compounds and particulate matter. And the initial evaluation experiments for SOA yields from the ozonolysis of α-pinene and for mass spectra of the products resulting from the photooxidation of OH initiated isoprene are also presented, which indicate the applicability of this facility on the studies of gas-phase chemical mechanisms as well as the formation of SOA expected in the atmosphere.

Response of Ecosystem Respiration to Experimental Warming and Clipping at Daily Time Scale in an Alpine Meadow of Tibet

The alpine meadow, as one of the typical vegetation types on the Tibetan Plateau, is one of the most sensitive terrestrial ecosystems to climate warming. However, how climate warming affects the carbon cycling of the alpine meadow on the Tibetan Plateau is not very dear. A field experiment under controlled experimental warming and clipping conditions was conducted in an alpine meadow on the Northern Tibetan Plateau since July 2008. Open top chambers （0TCs） were used to simulate climate warming. The main objective of this study was to examine the responses of ecosystem respiration （Reco） and its temperature sensitivity to experimental warming and clipping at daily time scale. Therefore, we measured Reco once or twice a month from July to September in 2010, from June to September in 2011 and from August to September in 2012. Air temperature dominated daily variation of Reco whether or not experimental warming and clipping were present. Air temperature was exponentially correlated with Reco and it could significantly explain 58-96% variation of Redo at daily time scale. Experimental warming and clipping decreased daily mean Reco by 5.8-37.7% and -11.9-23.0%, respectively, although not all these changes were significant. Experimental warming tended to decrease the temperature sensitivity of Reco, whereas clipping tended to increase the temperature sensitivity of Reco at daily time scale. Our findings suggest that Reco wasmainly controlled by air temperature and may acclimate to climate warming due to its lower temperature sensitivity under experimental warming at daily time scale.

Acoustic emission generated during the gas sorption-desorption process in coal

An experimental system for monitoring the acoustic signals generated in coal during gas sorption and/or desorption was designed and the acoustic signals were observed under different gas pressures. The experimental results show that signals generated by the coal during gas adsorption are attenuated over time. Also, the signals are not continuous but are impulsive. The intensity of the signals generated during gas desorption is far smaller than that observed during adsorption. The signal seen during desorption remains essentially stable. Cycles of sorption and desorption cause acoustic emission signals that exhibit a memory effect, which depends upon the maximum gas pressure the sample was exposed to in earlier cycles. Lower pressures in subsequent cycles, compared to the maximum adsorption pressure in previous cycles, cause both the energy and impulse frequency to be lower than previously. On the contrary, a gas adsorption pressure that exceeds the maximum pressure seen by the sample during earlier cycles causes both the energy and impulse frequency to be high.

Dynamic action simulation system and preliminary experiments of coal seams and gas

In order to study the dynamic action and physical effects of coal seams and gas, a simulation system for this dynamic action was developed and a physical model built in our laboratory. Using this newly built model, the volume of coal outbursts and the temperature during the outburst process were studied. The results show that： l） for coal seams with similar structure and com- ponents, two factors, i.e., gas pressure and ground stress affect the volume of coal outbursts, with gas pressure being the more im- portant of the two and 2） the changes in coal temperature, both its increase and decrease, are affected by ground stress and gas pressure, it is a process of change. Preliminary tests show that the system can simulate the dynamic interaction of coal and gas, which is helpful for studying the dynamic mechanism of solid-gas coupling of gas and coal.

Experimental study on gas–liquid dispersion and mass transfer in shear-thinning system with coaxial mixer

The effects of impeller type, stirring power, gas flow rate, and liquid concentration on the gas–liquid mixing in a shear-thinning system with a coaxial mixer were investigated by experiment, and the overall gas holdup, relative power demand, and volumetric mass transfer coefficient under different conditions were compared. The results show that, the increasing stirring power or gas flow rate is beneficial in promoting the overall gas holdup and volumetric mass transfer coefficient, while the increasing system viscosity weakens the mass transfer in a shearing–thinning system. Among the three turbines, the six curved-blade disc turbine(BDT-6) exhibits the best gas pumping capacity; the six 45° pitched-blade disc turbine(PBDT-6) has the highest volumetric mass transfer coefficient at the same unit volume power.

Aerodynamic interference effects between a triple-box girder and trains on aerodynamic forces and vortex-induced vibration

Wind tunnel tests were carried out to investigate the aerodynamic interference between a triple-box girder and trains,involving static aerodynamic forces and vortex-induced vibrations(VIVs).Static and dynamic sectional models of the girder and trains were employed for aerodynamic force measurement and VIV test,respectively.Results indicate that the aerodynamic interference effect on static aerodynamic forces of both the girder and trains is remarkable.When a single train exists,the horizontal position of the train has a small effect on aerodynamic coefficients of the girder.When two trains meet on the girder,the drag coefficient of the girder is significantly reduced compared with that of without train or with a single train;besides,during the whole meeting process,aerodynamic forces of the leeward train first drop and then increase suddenly.The fluctuation of aerodynamic force could cause redundant vibration of the train,which is unfavorable for safety and comfort.A train on the girder could worsen the girder VIV performance:a new vertical VIV appears in the triple-box girder when a train is on the girder,and the torsional VIV amplitude increases significantly when the train is on the windward side.

Introduction of CMIP5 Experiments Carried out with the Climate System Models of Beijing Climate Center

The climate system models from Beijing Climate Center, BCC_CSM1.1 and BCC_CSM1.1-M, are used to carry out most of the CMIP5 experiments. This study gives a general introduction of these two models, and provides main information on the experiments including the experiment purpose, design, and the external forcings. The transient climate responses to the CO2 concentration increase at 1% per year are presented in the simulation of the two models. The BCC_CSM1.1-M result is closer to the CMIP5 multiple models ensemble. The two models perform well in simulating the historical evolution of the surface air temperature, globally and averaged for China. Both models overestimate the global warming and underestimate the warming over China in the 20th century. With higher horizontal resolution, the BCC_CSM1.1-M has a better capability in reproducing the annual evolution of surface air temperature over China.

Experimental assessment of two-phase bubble pump for solar water heating

The research goal is to develop a new solar water heater system(SWHS) that uses a solar bubble pump instead of an electric pump.The pump is powered by the steam produced from an evacuated tube collector.Therefore,heat could be transferred downward from the collector to a hot water storage tank.The designed system consists of two sets of heat-pipe evacuated tube collectors,a solar bubble pump installed at an upper level and a water storage tank with a heat exchanger at a lower level.Discharge heads of 1 and 5 m were tested.The bubble pump could operate at the collector temperature of about 90-100 ℃ and vapor gage pressure of 80-90 kPa.It is found that water circulation within the SWHS depends on the incident solar intensity and system discharge head.Experimental investigations are conducted to obtain the system thermal efficiencies from the hourly,daily and long-term performance tests.The thermal performance of the proposed system is compared with conventional solar water heaters.The results show that the proposed system achieves system characteristic efficiency of 10% higher than that of the conventional systems using electric pump if taking the consumption of electric power into account.And the former is a zero carbon system.

Semi-empirical modeling of volumetric efficiency in engines equipped with variable valve timing system

Volumetric efficiency and air charge estimation is one of the most demanding tasks in control of today's internal combustion engines.Specifically,using three-way catalytic converter involves strict control of the air/fuel ratio around the stoichiometric point and hence requires an accurate model for air charge estimation.However,high degrees of complexity and nonlinearity of the gas flow in the internal combustion engine make air charge estimation a challenging task.This is more obvious in engines with variable valve timing systems in which gas flow is more complex and depends on more functional variables.This results in models that are either quite empirical(such as look-up tables),not having interpretability and extrapolation capability,or physically based models which are not appropriate for onboard applications.Solving these problems,a novel semi-empirical model was proposed in this work which only needed engine speed,load,and valves timings for volumetric efficiency prediction.The accuracy and generalizability of the model is shown by its test on numerical and experimental data from three distinct engines.Normalized test errors are 0.0316,0.0152 and 0.24 for the three engines,respectively.Also the performance and complexity of the model were compared with neural networks as typical black box models.While the complexity of the model is less than half of the complexity of neural networks,and its computational cost is approximately 0.12 of that of neural networks and its prediction capability in the considered case studies is usually more.These results show the superiority of the proposed model over conventional black box models such as neural networks in terms of accuracy,generalizability and computational cost.

Dependency of Electrical Demand of Bangladesh Power System on the Weather of the Country

The variation of electrical demand above its base value is its common characteristic. The weather dependent variation of demand, especially where the weather is severe in nature, requires a significant reserve margin of the generation system. The evaluation of the weather dependent component of the electric demand is the basic tool for the planning of the reserve margin. This paper evaluates the weather dependent portion of the load of BPS （Bangladesh power system）. The evaluation of the weather dependent portion of the demand is based on the EMD （empirical mode decomposition） technique.

Bubble Pump Models Verification Based on the Experimental Results

DAR （diffusion absorption refrigeration） cycle is driven by heat and has no moving parts. It is based on refrigerant and absorbent as the working fluid together with hydrogen as an auxiliary inert gas. To circulate the working fluid without a mechanical pump, the diffusion absorption cycle relies on a bubble pump. Experimental system was designed and operated. Its aim was to investigate the performance of a bubble pump operating with three lifting tubes. The experimental results of the system were compared to existing models. The comparison showed that there was a bad agreement between the experimental and the theoretical results.

Large-scale Experimental System for Multiphase Fuel/Air Explosions

A large-scale experimental for multiphase combustion and explosion study was developed and manufactured. The explosion tank consists of a 2 m diameter, 3.5 m long tube and ellipsoidai dames on both ends. The volume of the experimental tank is 10 ma. Pressure histories of the explosion pressure can be measured at different locations in the tank. High pressure glass windows of 200～300 mm were used to have access to the visualization of the explosion process. The explosion process of methane/air mixture and methane/coal dust/air mixture initiated by a 40 J electric spark at the center of the tank was studied in the large^scale experimental system. Five pressure sonsars were arranged in the tank with different distances from the ignition point. Ton dust dispersion traits were equipped to eject dust into the tank. A high-speed camera system was used to visualize the flame propagation during the explosion process. The characteristics of the pressure wave and flame propagated in methane/air mixtures and methane/coal dust/air mixtures have been

The Potentially Dangerous Asteroid （99942） Apophis

This paper computed the newest impact solutions of the potentially dangerous asteroid （99942） Apophis based on 4,138 optical observations from March 15.10789 UTC （Universal Time Coordinated）, 2004 to February 28.089569 UTC, 2014 and 20 radar observations from January 27, 2005 through March 15, 2013, as of June 20, 2014. Using the freely available the OrbFit software Package, this paper followed its orbit forward in the searching for close approaches with the Earth and possible impacts up to year 2116. With the different A2 non-gravitational parameter in the motion of the asteroid （99942） Apophis, this paper computed possible impact solutions using the JPL DE405 （Jet Propulsion Laboratory Development Ephemeris） and 25 additional massive perturbed asteroids. Additionally, this paper used weighing and selection methods adopted in the OrbFit software as prepared by the NEODyS （Near Earth Objects--Dynamical Side） Team. Moreover, this paper used method of computing the orbit of Apophis taking into account star catalog debiasing and an error model with assumed astrometric errors RMS （root mean square）, deduced from the observational material of the given observatories. JPL＇s Sentry and NEODyS＇s CLOMMON2, two automatic monitoring systems routinely scanning for possible impacts in the next hundred years. Only for several dangerous asteroids presented results are computed with the non-gravitational parameters. This paper detected possible impacts of the asteroid （99942） Apophis only with the non-gravitational parameter, A2 〉 0. It was appeared that impacts in 2068, 2087, 2105 and in 2111 were possible only when Apophis rotated in prograde direction.

An introduction to the novel vacuum plume effects experimental system

This paper introduces a newly developed vacuum Plume effects Experimental System(PES) used for plume effect tests of rocket engines and vacuum heat tests of satellites. The design level, manufacturing technique, and testing capabilities of the PES have reached a highly advanced level at home and abroad. The PES mainly consists of a vacuum chamber, vacuum acquisition system, nitrogen system, helium system, and parameter measurement system. A breakthrough was obtained on the Large Scale Cryo-Pumping System, which was based on a combined liquid nitrogen and liquid helium heat sink. An internal cryopump with a limiting temperature of 4.2 K and an efficient absorption area of 305 m2 was developed. The absorption capability of the cryopump was above 7×107 L/s. Vacuum plume tests were performed in the temperature ranges of ambient temperature, liquid nitrogen, and liquid helium. The experimental results showed that the plume test capability of PES is higher than that of similar foreign equipment STG and CHAFF-4. For 2 g/s and 117 N rocket engines, the dynamic vacuum degree of environment was 8.0×10?4 Pa(approximately 137 km height) and 1.1×10?2 Pa(approximately 106 km height), respectively.

Effect of Vane Opening on Aerodynamic Performance of the Ram-rotor Test System

In order to research the influence of adjustable vane on the aerodynamic performance of the ram-rotor test system, FLUENT soft-ware has been adopted to simulate the flow passage of the ram-rotor test system numerically. The vane opening is controlled by changing the stagger angle of the vane blades. Results show that flow uniformity of vane outlet is influenced by the vane openings, which has an impact on the aerodynamic loss to some extent. Total pressure ratio, adiabatic efficiency and mass flow rate can be regulated by different openings of the vane. Compared with -8° vane opening, top efficiency of the ram-rotor increases by about 13.8% at ＋6° opening. And total pressure ratio drops by 5.87%. The rising opening increases the relative Mach number at inlet of the ram-rotor and weakens the intensity of the tip clearance leakage, which comes to a decreasing aerodynamic loss.

Wind tunnel test on aerodynamic effect of wind barriers on train-bridge system

To investigate the aerodynamic effect of wind barriers on a high-speed train-bridge system,a sectional model test was conducted in a closed-circuit-type wind tunnel.Several different cases,including with and without barriers,with different barrier heights and porosity rates,and with different train arrangements on the bridge were taken into consideration;in addition,the aerodynamic coefficients of the train-bridge system were measured.It is found that the side force and rolling moment coefficients of the vehicle are efficiently reduced by a single-side wind barrier,but for the bridge deck these values are increased.The height and porosity rate of the barrier are two important factors that influence the windbreak effect.Train arrangement on the bridge will considerably influence the aerodynamic properties of the train-bridge system.The side force and rolling moment coefficients of the vehicle at the windward side are larger than at the leeward side.

Systematic review of randomized controlled trials of traditional Chinese medicine treatment of non-acute bronchial asthma complicated by gastroesophageal reflux

OBJECTIVE:To assess the effectiveness and safety of Traditional Chinese Medicine(TCM) treatment of non-acute bronchial asthma complicated by gastroesophageal reflux.METHODS:We searched databases from MEDLINE,Cochrane Library,CNKI,VIP,CBM,Wanfang Data,and TCM Database Systems.All randomized,controlled trials(RTCs) of TCM treatment of non-acute asthma complicated by gastroesophageal reflux were included.Data were independently collected by two reviewers.The standards for assessing quality described in the Cochrane Handbook for Systematic Reviews of Interventions were used to evaluate articles.Meta-analyses were conducted using RevMan 5.0.17 software.Heterogeneity was assessed,and a corresponding effects model was used to merge and analyze results.Indexes used to evalu-ate curative effects were:clinical efficacy,symptom scores,pulmonary function values,and adverse incidents.Effectiveness was indicated using risk ratio(RR) or mean difference(MD),and 95% confidence intervals(CIs) were calculated.RESULTS:Six RCTs were included,involving 304 patients with non-acute asthma complicated by gastroesophageal reflux.The treatment groups received Chinese drugs alone or TCM combined with standard Western medical treatment,and the control groups received standard Western medical treatment alone.Standard Western medical treatment included anti-inflammatory drugs and bronchodilators for asthma,and drugs to promote gastric peristalsis and inhibit gastric acid production for gastroesophageal reflux.Methodological quality was low in all six RCTs.Two RCTs showed that clinical efficacy was higher in the treatment group than in the control group(RR:1.43,95%CI:1.10 to 1.87 vs RR:1.51,95% CI:1.09 to 2.08).One RCT showed that the asthma score was lowered more effectively in the treatment group than in the control group(MD:-1.10,95% CI:-2.04 to-0.16).Two RCTs showed that the gastroesophageal reflux score was reduced more effectively in the treatment group than in the control group(RR:-3.70,95% CI:-4.30 to 3.10 vs RR:-5.30,95% CI:-6.32 to-4.28).One RCT showed that some pulmonary function values were improved more effectively in the treatment group than in the control group(P< 0.05).No differences were seen in the various indexes between groups in the other RCTs.No adverse reactions,dropout rates,or follow-up rates were reported in any of the RCTs.CONCLUSIONS:The clinical symptoms ofnon-acute asthma complicated by gastroesophageal reflux can be improved by some Chinese drugs.Curative effects can be increased by combining the use of TCM with Western medicine.Because of the small quantity and low quality of research reported to date,it is necessary to conduct further RCTs to confirm these results.The results of this systematic review indicate that the quality of future clinical trials should be improved by including larger patient numbers,correctly randomizing patients into study groups,using blinding methods to measure and assess outcomes,and using accepted indexes to evaluate curative effects.

Chinese patent medicine for chronic obstructive pulmonary disease based on principles of tonifying Qi, promoting blood circulation by removing blood stasis, and resolving phlegm: a systematic review of randomized controlled trials

OBJECTIVE: To assess the efficacy and safety of Chinese patent medicine(CPM) with the principle of tonifying Qi, promoting blood circulation by removing blood stasis, and resolving phlegm(TQ-PBC-RP)in the management of stable chronic obstructive pulmonary disease(COPD).METHODS: A systematic review of randomized controlled trials(RCTs) identified from electronic databases and print was conducted. RCTs testing CPMs with TQ-PBC-RP against any type of controlled intervention in patients with stable COPD and assessing clinically relevant outcomes were included. Methodological quality was evaluated with the risk of bias tool according to systematic review handbook 5.0.2. Quality of evidence was estimatedby the rating approach developed by the Grading of Recommendations, Assessment, Development,and Evaluation Working Group.RESULTS: Thirteen eligible RCTs with 12 oral CPMs were tested. Significant differences between groups in favor of CPMs were not reported in all trials. Most trials included were deemed to be of low methodological quality with poor evidence quality.Because of large data heterogeneity, statistical pooling was not performed for all outcomes.CONCLUSION: The effectiveness of CPM in the treatment of stable COPD is not supported by evidence. Currently, evidence from RCTs is scarce and methodologically weak. Considering the popularity of CPMs among patients undergoing COPD, rigorously designed trials are warranted.

Experimental Study on the Inlet Fogging System Using Two-Fluid Nozzles

Large-capacity compressors in industrial plants and the compressors in gas turbine engines consume a considerable amount of power. The compression work is a strong fimction of the ambient air temperature. This increase in compression work presents a significant problem to utilities, generators and power producers when electric demands are high during the hot months. In many petrochemical process industries and gas turbine engines, the in- crease in compression work curtails plant output, demanding more electric power to drive the system. One way to counter this problem is to directly cool the inlet air. Inlet fogging is a popular means of cooling the inlet air to air compressors. In the present study, experiments have been performed to investigate the suitability of two-fluid nozzle for inlet fogging. Compressed air is used as the driving working gas for two-fluid nozzle and water at am- bient conditions is dragged into the high-speed air jet, thus enabling the entrained water to be atomized in a very short distance from the exit of the two-fluid nozzle. The air supply pressure is varied between 2.0 and 5.0 bar and the water flow rate entrained is measured. The flow visualization and temperature and relative humidity measurements are carried out to specify the fogging characteristics of the two-fluid nozzle.