不同气锤组合方式的气动式振动台性能研究

气动式振动台振动信号的频域能量分布不均匀且低频能量较低,这限制了该设备在电子产品可靠性强化试验中的进一步应用.由于商业竞争和技术保密等原因,目前国内对该设备的优化设计与自主研发尚未全面展开.根据薄板振动理论建立了气动式振动台的力学模型,采用能量法(Rayleigh-Ritz法)分析和计算了振动台面的固有频率和正则振型,针对三种不同的气锤组合方式,采用分析多自由度系统响应的振型叠加法分别计算了振动台面的强迫振动响应,进而对气动式振动台振动信号产生的机理进行了探索.在此基础上,根据气动式振动台的性能评价指标,进一步对三种气锤组合方式的气动式振动台性能优劣进行了评价,为整个气动式振动台的性能改善及自主研发提供了理论指导.     

高比例配加外粉的烧结生产实践

针对河钢宣钢外粉配比升高后,烧结负压大幅下降、烧结矿强度和粒级等质量指标出现下滑的问题,通过实施800 mm厚料层生产、降低入烧混合料水分、优化入烧燃料粒度、提高点火负压等工艺参数控制,以及优化烧结矿FeO和MgO含量、改进布料方式、控制返矿质量,烧结工艺过程稳定、可控;烧结矿转鼓强度指标维持在78. 5%左右,烧结矿粒径提高到平均20. 5 mm;还原性指标提高至80. 3%,达到历史最好水平。优化措施实施后,烧结矿质量及性能可较好地满足高炉的生产要求。     

A fast digital chip implementing a real-time noise-resistant algorithm for estimating blood pressure using a non-invasive,cuffless PPG sensor

Microsystem Technologies - A fast digital chip is designed and fabricated successfully to implement the algorithm for estimating blood pressure (BP) in real time by a non-invasive cuffless...     

Correlation of musty odor and 2-MIB in two drinking water treatment plants in South Taiwan

Possible odor groups and intensity, and seasonal effects were elucidated in two representative water treatment plants (WTPs), Feng-Shen and Gun-Shi, in southern Taiwan. The flavor profile analysis (FPA) was employed to determine the odor groups for the source water, while a chemical analysis, solid-phase microextraction (SPME) coupled with a gas chromatograph and mass spectrometric detector (GC/MSD), was used to concentrate and subsequently analyze the corresponding water samples. FPA results show that fishy and musty odors were the two major odor groups in the source water. Results of chemical analysis showed that 2-methyl-isoborneol (2-MIB) was present in the source water. The correlation between 2-MIB concentration and the FPA intensity of musty odor was compared with the dose-response curve generated in the laboratory by the FPA panelists. The experimental data from the two water treatment plants follow the calibration curve closely, indicating that the musty odor of the two source waters were most likely contributed from 2-MIB. In addition, there is good correlation between logarithmic 2-MIB concentration and water temperature, substantiating the importance of seasonal effect. Although approximately 40-50% of 2-MIB removal was found in the treatment trains for the two WTPs, only an approximately 0.3 FPA intensity scale of reduction was expected.     

Critical path effect based delay analysis method for construction projects

Assessing schedule delay's impact on total project duration to distribute delay liability remains a controversy. None of existing delay analysis methods is perfect because including an element of assumptions, subjective assessment and theoretical projection. Windows-based delay analysis methods are excellent in identifying and measuring construction schedule delays. Based on a previous study identifying potential problems in available windows-based delay analysis methods, this study proposes an innovative windows-based delay analysis method, called the effect-based delay analysis method (the EDAM method). The EDAM method performs delay analysis using extracted windows and determines delay impacts by considering the effects of delays on the critical path(s). According to its application to hypothetical cases and comparisons with other methods, the EDAM method is efficient in delay analysis and effective in solving concurrent delays and determining schedule shortened. The proposed EDAM method is a good alternative for schedule delay analysis for construction projects.     

逆作法施工支撑立柱抬升与沉降分析

通过对基坑开挖引起支撑立柱抬升与沉降的原因分析 ,阐明逆作法施工时支撑立柱产生不均匀沉降的原因 ,从而提出采取控制挖土速度等措施减小支撑立柱间的不均匀沉降     

砖墙抹灰横向开裂原因分析及修补

龟裂、空鼓等现象都属于砖墙抹灰常见的质量通病 ,而抹灰层横向开裂的情况并不多见。本文结合工程实例 ,论述了砂浆收缩、施工操作不当等因素是抹灰层横向开裂的原因 ,并提出修补措施     

Factors affecting the biodegradation of PCP by Pseudomonas mendocina NSYSU

A pentachlorophenol (PCP) degrading bacterium was isolated from PCP-contaminated soils and identified as Pseudomonas mendocina NSYSU (P. mendocina NSYSU). The main objectives of this study were to (1) clarify the factors affecting the ability and efficiency of PCP biodegradation by P. mendocina NSYSU, and (2) optimize the use of this bacterium in bioremediation of PCP. Microcosm experiments were conducted to fulfill the objectives. In batch cultures, P. mendocina NSYSU used PCP as its sole source of carbon and energy and was capable of completely degrading this compound. This was confirmed by the stoichiometric release of chloride ion. Moreover, P. mendocina NSYSU was able to mineralize a high concentration of PCP (150 mg/L). Results from the oxygen concentration experiment reveal that the growth of P. mendocina NSYSU was inhibited under low oxygen and anaerobic conditions. Results indicate that the optimal growth conditions for P. mendocina NSYSU include the following: slightly acidic (6相似文献