A Pragmatic Approach to Product Costing Based on Standard Time Estimation

The major drawbacks of traditional approaches to product costing include lack of manufacturing knowledge, reliance on the detailed design description, poor cost function approximation and inability to update estimation algorithms by using actual cost data. Adopting the Activity-Based Costing (ABC) concept and based on estimated processing time, this paper proposes a pragmatic approach to product costing. The approach involves two stages, namely the preparatory stage and the estimation stage. A case study conducted in a refrigerator company is reported.

The time and frequency standard system for FAST receivers

This paper reports on the time and frequency standard system for the Five-hundred meter Aperture Spherical radio Telescope(FAST),including the system design,stability measurements and pulsar timing observations.The stability and drift rate of the frequency standard are calculated using 1-year monitoring data.The UTC-NIM Disciplined Oscillator(NIMDO)system improves the system time accuracy and stability to the level of 5 ns.Pulsar timing observations were carried out for several months.The weighted RMS of timing residuals reaches the level of less than 3.0μs.

Noether symmetry and conserved quantity for dynamical system with non-standard Lagrangians on time scales

This paper focuses on studying the Noether symmetry and the conserved quantity with non-standard Lagrangians, namely exponential Lagrangians and power-law Lagrangians on time scales. Firstly, for each case, the Hamilton prin- ciple based on the action with non-standard Lagrangians on time scales is established, with which the corresponding Euler-Lagrange equation is given. Secondly, according to the invariance of the Hamilton action under the infinitesimal transformation, the Noether theorem for the dynamical system with non-standard Lagrangians on time scales is established. The proof of the theorem consists of two steps. First, it is proved under the infinitesimal transformations of a special one-parameter group without transforming time. Second, utilizing the technique of time-re-parameterization, the Noether theorem in a general form is obtained. The Noether-type conserved quantities with non-standard Lagrangians in both clas- sical and discrete cases are given. Finally, an example in Friedmann-Robertson-Walker spacetime and an example about second order Duffing equation are given to illustrate the application of the results.

Estimation of Standard Operation Time of Flight Legs Based on Clustering and Probability Analysis

A clustering algorithm and a probability statistics method were applied to different phases of a flight to analyze operation time during aircraft ground taxiing and airborne flight.And the clustering pattern,distribution characteristics and dynamically changing rules of the two phases were identified.Further,an estimate method was established to measure operation time of flight legs,with creative steps of calculating individual segment separately and then integrating them accordingly.The method can both objectively and dynamically measure operation time,and accurately reflect real situation.It helps to better utilize airport slot resources and provides a strong support for air traffic flow management when scheduling flight plan in strategic and pre-tactic phases.

Construction and evaluation of reference standards for detection and quantification of Klebsiella pneumoniae using real-time PCR

Objective To construct reference standards for detection and quantification of Klebsiella pneumoniae(K.pneumoniae)with SYBR Green I-based real-time PCR assay.Methods Primers were designed based on the published sequence of the phoE gene of K.pneumoniae.The standard was prepared by cell culture,PCR and T-A clone methods,and was identified by colony PCR and DNA sequencing.Results The standard curve showed a very good linear negative regression between threshold cycle(Ct)and Log starting quantity of copy number.The detection range was from 5.2 to 5.2×106 copies per reaction,and the detection limit was 6 copies per reaction.The coefficients of variance(CVs)of three parallel experiments were in the range of 0.05%-0.91%.Conclusion The reference standards have high stability and reproducibility.They can be used in the quantitative detection of K.pneumoniae.

An improved formula for standard hypoxia tolerance time to evaluate hypoxic tolerance in mice

Background: Hypoxia is a primary cause of mountain sickness and a common pathological condition in patients with heart failure, shock, stroke, and chronic obstructive pulmonary disease(COPD). Thus far, little advancement in countering hypoxic damage has been achieved, and one of the main reasons is the absence of an ideal algorithm or calculation method to normalize hypoxia tolerance scores when evaluating an animal model. In this study, we improved a traditional calculation formula for assessment of hypoxia tolerance.Methods: We used a sealed bottle model in which the oxygen is gradually consumed by a mouse inside. To evaluate the hypoxia tolerance of mice, the survival time(ST) of the mouse is recorded and was used to calculate standard hypoxia tolerance time(STT) and adjusted standard hypoxia tolerance time(ASTT). Mice administered with methazolamide and saline were used as positive and negative controls, respectively.Results: Since mice were grouped according to either body weight(BW) or bottle volume, we found a strongly negative correlation between STT and BW instead of between STT and bottle volume, suggesting that different BWs could cause false positive or negative errors in the STT results. Furthermore, both false positive and negative errors could be rectified when ASTT was used as the evaluation index. Screening for anti-hypoxic medicines by using mice as the experimental subjects would provide more credible results with the improved ASTT method than with the STT method.Conclusions: ASTT could be a better index than STT for the evaluation of hypoxia tolerance abilities as it could eliminate the impact of animal BW.

Investigating the Use of <i>Jatropha</i>Biodiesel in Compression Ignition Engines by Comparing Effects of Storage Time on Its Properties with the Standard Properties of Fossil-Diesel and Properties of Quality Biodiesel

Effects of storage time on some properties of jatropha biodiesel were investigated over the storage time of 0 to 8 weeks at the temperature of 25℃. Such properties as water content and density were found to increase at the rates of 5 ppm and 14 kg/m3 per week respectively. These rates translate into property values which compare closely with the standard properties of fossil-diesel and properties of quality biodiesel. As a result, the jatropha biodiesel can be used as alternative fuel to fossil-diesel in compression ignition engines within 8 weeks of its production. However, the calorific value and flash point of the biodiesel decreased at the rate of 1.4℃ and 2.5 MJ/kg per week respectively. Although the flash point was within the acceptable level for quality biodiesel, the calorific values were abnormally higher than the values for quality biodiesel of about 38.7 MJ/kg. With the exception of the calorific values, the other properties were not reasonably affected.

China National Standards on Nano-Materials Issued for the First Time

On February 28th, 2005, AQSIQ (the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China), and SAC (the Standardization Administration of P. R. China)jointly hosted the press conference on seven items of national standards on nano-materials in Beijing. The seven items of national standards were approved on Sept. 29th and Dec. 27th, 2004 respectively by SAC, and publicized in Jan. 2005. They will be formally put into practice from April 1st, 2005.

Generation and Application of A Standardized Load-Time History to Tubular T-joints in Offshore Platforms

Marine structures are mostly made of metals and always experience complex random loading during their service periods. The fatigue crack growth behaviors of metal materials have been proved from laboratory tests to be sensitive to the loading sequence encountered. In order to take account of the loading sequence effect, fatigue life prediction should be based on fatigue crack propagation（FCP） theory rather than the currently used cumulative fatigue damage（CFD） theory. A unified fatigue life prediction（UFLP） method for marine structures has been proposed by the authors＇ group. In order to apply the UFLP method for newly designed structures, authorities such as the classification societies should provide a standardized load-time history（SLH） such as the TWIST and FALSTAFF sequences for transport and fighter aircraft. This paper mainly aims at proposing a procedure to generate the SLHs for marine structures based on a short-term loading sample and to provide an illustration on how to use the presented SLH to a typical tubular T-joint in an offshore platform based on the UFLP method.

不同比对方式下的洲际标准时间复现性能分析

中国科学院国家授时中心研制的标准时间复现系统具备支持洲际用户对标准时间频率信号的需求。本文以位于欧洲白俄罗斯明斯克的复现终端为分析对象,分析了共视、全视不同比对方式对复现时频信号性能的影响。对于洲际范围的时间复现,复现终端与参考端共同可视卫星数变少。单一卫星导航系统可利用的共视卫星数明显减少,GPS/BDS共视可明显增加可视卫星数量,提高共视时间比对精度,全视比对对两地共同可视卫星数没有要求。分析结果表明,单GPS全视比对就可以达到优于GPS/BDS的共视比对复现效果。受BDS卫星星间偏差的影响,基于单BDS全视比对的复现效果比GPS稍差,GPS/BDS全视比对效果略有改善。复现终端运行在GPS/BDS共视比对融合GPS全视比对模式复现的时频信号的性能最优,可以满足洲际范围内5 ns的时间同步要求,为后续洲际大尺度范围的标准时间复现终端的运行模式提供参考。

美国加州车网互动政策、标准与市场机制最新进展及其启示

电动汽车与电网互动(简称“车网互动”)可以释放电动汽车作为灵活性资源的潜力,能够有效提升电网调峰能力、促进高比例可再生能源消纳、提升电动汽车用户经济收益,日益受到各方重视。美国加利福尼亚州(简称“加州”)近些年在推动电动汽车与电网互动发展方面做了大量工作,取得了重要进展。首先,文中介绍了加州在电动汽车与电网互动配套政策法规方面的最新动向;之后,从技术标准、市场机制两方面介绍了加州在电动汽车与电网互动相关基础工作方面的最新进展;最后,结合中国电动汽车与电网互动发展实际提出了有关建议。

NIM5驾驭氢钟守时能力分析

时间频率量值源头的独立自主是建设我国综合PNT体系的重要基础。为进一步评估基于我国国家秒长基准的原子时标守时能力,利用改进的有限脉冲响应钟差预测与频率调控方法,对激光冷却铯原子喷泉钟与氢钟的频差实测数据进行后处理,分别产生了自主型时标和溯源型时标。通过国际原子时合作链路将两个时标与协调世界时进行了长期比对实验,结果表明:2021年12月~2022年12月期间,两个时标的时间偏差均优于±4 ns、频率稳定度均优于8×10^(-16)/5 d。

基于改进PCA的复杂多阶段过程故障检测

为解决复杂多阶段过程难以进行有效监控的问题,提出了时空近邻标准化和主成分分析的故障检测方法。TSNS使用从时间到空间上嵌套近邻集的均值和标准差标准化各阶段样本,能够将多阶段数据高斯化为单一阶段的数据,分离故障样本,同时去除前后时刻样本间的时序相关性。TSNS能帮助PCA有效克服动态性、非线性和多阶段特征的影响,显著提高PCA的故障检测率。通过使用青霉素发酵过程设计故障检测实验,将TSNSPCA与一些经典方法进行比较,发现其具有更高的故障检测率。

基于OSEKTime的共存模型的改进与实现

OSEKTime规范提出了基于时间触发操作系统与基于OSEK/VDX标准实现的操作系统的共存模型。在分析OSEKTime规范的基础上,针对该规范的消息触发任务存在着非实时性问题,提出并实现了一种合理的、能与OS-EK OS共存的实时时间触发操作系统,确保了时间触发任务的实时性和对消息触发任务的死限时间内的及时处理。

《中国医院质量安全管理》团体标准应用对手术质量的影响:以结肠手术为例

目的以《中国医院质量安全管理第4-8部分:医疗管理医院感染管理》对于结肠手术的影响为例,评估《中国医院质量安全管理》团体标准应用对于外科手术服务质量的影响及其实施效果。方法以医院信息系统为依托,分别提取2018年10月1日-2019年9月30日(标准实施前)与2019年10月1日-2020年9月30日(标准实施后)结肠手术患者数据,分析与比较患者年龄、共病等基础特征,并采用间断性时间序列分析(ITSA),评估标准实施对于不良事件、住院时长的影响。结果研究共纳入4442例结肠手术患者,其中标准实施前的患者为2936例,实施后的患者为1506例。单因素分析显示,与标准实施前相比,标准实施后的结肠手术患者共病指数较高(2.25±4.95 vs 3.95±6.14,P<0.0001),恶性肿瘤患病率较高(14.03%vs 26.10%,P<0.0001),平均住院日增加(10.95±8.52 vs 13.29±9.50,P<0.0001),但不良事件发生率并未提高(1.12%vs 0.86%,P=0.4164)。ITSA显示,标准实施后,不良事件发生率与住院时长均无显著增加。结论医院质量安全管理标准的实施可在一定程度上应对患者病情的加重对于临床结局造成的负面影响,保障医疗服务的质量安全。

Real-time PCR检测风疹病毒方法学建立及临床应用

为了建立一种能广泛应用于临床快速、简便、灵敏度和特异性较好的风疹病毒（RV）定量诊断方法。针对RV基因保守序列设计两对引物和一条荧光双标记探针。将PCR扩增所得到的产物片段克隆，作为定量检测的标准品，进行Real—timePCR检测，绘制标准曲线。将此方法和ELISA试剂盒平行检测50份孕妇血清，评估两种方法检出阳性率的差异显著性。Real—timePCR法能较好地检出RVcDNA载量。曲线的相关系数（r）为0．998，可检测线性范围大约在10^3～10^9copies／μl，灵敏度接近10^3copies／μl；批间、批内CV值分别为3．36％、0．94％；也有较好的特异性。与经典的ELISA方法相比，有显著性差异。Real—timePCR方法操作简单、快速，并能避免PCR后处理导致的假阳性污染，实现实时定量。此方法对RV感染的临床诊断和疗效判断等方面有较大的指导意义。

天然气净化行业氧化吸收尾气处理装置全时段达标排放经验浅谈

文章介绍了氧化类尾气处理装置的工艺原理和特点,分析了氧化类尾气处理装置在天然气净化行业正常工况、开停产期间,以及异常工况情况下尾气超标原因,提出了硫磺回收装置精准配风、控制尾气处理装置溶液浓度等具体解决措施,并从工艺流程优化、联锁设置、自动化改造等方面提出优化建议,确保氧化类尾气处理装置实现全时段达标。

标准化卒中疏导员制度促进溶栓治疗的作用研究

目的:评价标准化卒中疏导员制度促进溶栓治疗的作用。方法:主要方法为回顾性分析,选取2021年3月至2021年11月通过常规绿色通道流程进行溶栓的急性卒中病例为对照组,2021年12月至2022年8月实施卒中疏导员制度溶栓的急性卒中病例为观察组,比较两组患者入院到开始静脉溶栓治疗时间(DNT)差异,统计分析DNT时间延长原因。结果:观察组DNT时间显著短于对照组,差异有统计学意义(P<0.05),影响DNT时间的因素主要有6个方面,其中患方、抢救人力、CT检查为主要原因。结论:卒中疏导员制度不仅能有效改善卒中关键指标,还能发现过程短板并提出改进措施,对改进效果进行评价,有利于卒中救治质量的提升。

基于Innovus的局部高密度布局规避方法

标准单元布局是数字集成电路后端设计的重要环节之一,标准单元密度过高影响着工具的布线和时序的优化。采用UMC 28 nm工艺,基于Innovus的两种方法,解决由于局部高密度标准单元导致保持时间违例无法通过工具自动化修复的问题,在实现时序优化的同时降低了动态IR Drop。结果表明,在PreCTS阶段设置setPlaceMode-place_global_max_density value对于后续时序优化效果更好,且动态IR Drop降低8.85%。

Rancimat法测定燕麦粉中油脂的氧化诱导时间

本文以富含油脂的燕麦粉为研究对象,不采取提取油脂的方式,而是直接应用油脂氧化稳定性仪对固体粉末样品进行油脂氧化稳定性的研究,并确定了测定方法的适宜条件,如空气流量20L/h、称样量2g~3g、测试温度分别为110℃、120℃、130℃、140℃。通过几个高温下油脂氧化酸败诱导期的加速氧化测定,拟合出诱导时间与温度的关系方程,直接推算出油脂氧化稳定的货架期以及温度变化所引起的油脂氧化诱导时间的变化规律,具有快速、简便的特点,适于燕麦粉中油脂氧化诱导时间的测定。