浅谈EPG信息的地级市应用

简述了EPG相关原理及吉林省网EPG信息下传到吉林市二级网的应用,详细介绍了吉林市本地节目EPG信息的加入与下传的解决方案。     

可修改PSI调制器在数字电视中的应用

本文简述了数字电视中PSI/SI表结构和作用,并举例说明TT6120可修改PSI调制器在数字电视中的应用,具有很强的实用性.     

An experimental investigation on the use of EGR in a supercharged natural gas SI engine

The use of lean burn technology in spark-ignition engines has been dominant; however, lean burn technique can not economically satisfy the increasingly restricted future emission standards. Consequently, alternative combustion techniques need to be investigated and developed. In this paper, the use of the stoichiometric air-fuel mixture with exhaust gas recirculation (EGR) technique in a spark-ignition natural gas engine was experimentally investigated. Engine performance and NO emissions were studied for both atmospheric and supercharged inlet conditions. It was found that the use of EGR has a significant effect on NO emissions. NO emissions decreased by about 50% when EGR dilution increased from zero with an inlet pressure of 101 kPa to close to the misfire limit with an inlet pressure of 113 kPa. In addition, the use of EGR effectively suppressed abnormal combustion which occurred at higher inlet pressure. The use of higher inlet pressure in the presence of EGR improved engine performance significantly. Engine brake power increased by about 20% and engine fuel consumption decreased by about 7% while NO emissions decreased by about 12% when 5% of EGR dilution was employed with an inlet pressure of 113 kPa compared to using undiluted stoichiometric inlet mixture with an inlet pressure of 101 kPa.     

Jatropha curcas L. (Euphorbiaceae) modulates stomatal traits in response to leaf-to-air vapor pressure deficit

Cultivation of Jatropha curcas in arid and semiarid non-cultivated areas could be a sustainable strategy for stimulating biofuel production without competing with food crops for land and water resources. J. curcas is considered a drought-tolerant species; however, the mechanisms that provide tolerance are unknown. Few efforts have been made to understand the connections between stomatal development and environment conditions. Here, we compared changes in stomatal density (SD) and stomatal index (SI) and their influence on gas exchange in J. curcas. Plants were cultivated in both rainy and dry regions. We describe a distinctive distribution of stomata under the adaxial and abaxial leaf epidermises, where higher SD may have caused the increase in stomatal conductance (g_s) with positive effects on net photosynthetic rate (P_N). However, when rain was excluded, the variation in g_s was strongly related to vapour pressures deficit (VPD), and VPD was strongly related to the P_N. Thus, our results suggest that J. curcas may also contribute mitigating the effect of CO₂ deposition in the atmosphere, given that a remarkable change in SD and other leaf traits was observed in response to seasonal variations. Moreover, multivariate analysis highlights the high sensitivity of J. curcas plants to VPD which in turn induces rapid stomatal closure and consequent reduction of P_N for long periods of time which reflect into a change in the pattern of development resulting in higher SI. These results can help us to understand the relationship between stomatal features and gas exchange in response to environment changes.     

基于SI4432的915MHz射频读卡器设计

用Freecale公司的单片机MC9S12XS128为控制核心,以SiliconLabs公司的SI4432芯片设计制作模块做射频收发器,并给出读卡器的关键电路设计,根据ISO18000-TypeB标准给出了RFID读写器射频收发的软件设计流程,系统实现了小体积、低功耗、高灵敏度的无线数据传输。     

Ammonia combustion at elevated pressure and temperature conditions

This numerical study examines the combustion characteristics of premixed ammonia-air mixtures, with equivalence ratios around unity, at elevated pressure and temperature conditions which are encountered in SI engine operations. The laminar burning velocity, final flame temperature and species concentrations were determined using Konnov’s mechanism [18]. A flat, freely propagating flame was considered. Both equivalence and compression ratios have an important impact on both the laminar burning velocity and the adiabatic flame temperature. Furthermore, only the variation of the equivalence ratio has a major impact on the formation of nitrogen monoxide. It was found that the compression ratio and the final temperature do not have a significant impact on NO yields for equivalence ratios above unity.     

Impact of alcohol-gasoline fuel blends on the performance and combustion characteristics of an SI engine

In this study, the effects of ethanol-gasoline (E5, E10) and methanol-gasoline (M5, M10) fuel blends on the performance and combustion characteristics of a spark ignition (SI) engine were investigated. In the experiments, a vehicle having a four-cylinder, four-stroke, multi-point injection system SI engine was used. The tests were performed on a chassis dynamometer while running the vehicle at two different vehicle speeds (80 km/h and 100 km/h), and four different wheel powers (5, 10, 15, and 20 kW). The results obtained from the use of alcohol-gasoline fuel blends were compared to those of gasoline fuel. The results indicated that when alcohol-gasoline fuel blends were used, the brake specific fuel consumption increased; cylinder gas pressure started to rise later than gasoline fuel. Almost in the all test conditions, the lowest peak heat release rate was obtained from the gasoline fuel use.     

砌体结构基于群集智能的动力检测

本文提出基于新兴的群集智能算法对砌体结构剩余层间刚度进行识别,该方法仅利用环境激励下的结构响应信号,并根据识别的剩余刚度得到砌体结构的强度,从而达到对砌体结构进行安全性评估的目的。模拟结果表明该方法简单高效,易于实现,为已有砌体房屋的安全检测和质量评估提供一种新的方法与手段。     

DVB—C系统的复用技术

论述有线电视数字信号髑流的形成以及TS流的结构,并对数字信号的复用和解复用的原理和过程进行了分析,解析MPEG-2的PSI以及DVB—C系统的SI相关要点。     

广播网络中数字电视增值业务区域识别方法的研究与实现

本文以江苏有线南京分公司增值业务系统为例,研究在单向数字电视广播网络中,数字电视机顶盒终端利用传输流中的PSI／SI信息进行区域识别的方法,解决了前端统一推送增值业务时的区域选择问题。