灰关联模式评估模型在大学生体质健康水平综合评价中的应用

针对在大学生体质健康水平评价过程中指标权重确定、评价标准区分度等问题,讨论了单层和多层灰关联模式评估模型,并在权重的确定上采用熵权系数,以此为基础构建大学生体质健康水平综合评价体系,客观反映了大学生体质健康水平及个体间的差异.     

The AME 2020 atomic mass evaluation (I). Evaluation of input data,and adjustment procedures

This is the first of two articles(Part I and Part II)that presents the results of the new atomic mass evaluation,Ame2020.It includes complete information on the experimental input data that were used to derive the tables of recommended values which are given in Part II.This article describes the evaluation philosophy and procedures that were implemented in the selection of specific nuclear reaction,decay and mass-spectrometric data which were used in a least-squares fit adjustment in order to determine the recommended mass values and their uncertainties.All input data,including both the accepted and rejected ones,are tabulated and compared with the adjusted values obtained from the least-squares fit analysis.Differences with the previous Ame2016 evaluation are discussed and specific examples are presented for several nuclides that may be of interest to Ame users.     

Creep life evaluation of aluminum conductor composite core utilized in high voltage electric transmission

The creep life of aluminum conductor composite core (ACCC) utilized in high voltage electric transmission was investigated using an experimental method based on the equivalence relationship. First, the time-temperature-stress equivalence relationship was developed using the time-temperature and the time-stress equivalence relationships. Then, tensile creep experiments were conducted under different temperatures and different stress levels to obtain the strain-time curves of the ACCC. Finally, the creep strain master curve was obtained using the experimental data based on the time-temperature-stress equivalence relationship, allowing prediction of ACCC creep life. The results will play an important role in evaluation of the long-term characteristics of the ACCC for engineering applications.     

高速公路下伏多层倾斜采空区危害性评价数值模拟

采空区的危害性评价是矿区高速公路建设技术难题之一。应用二维及三维有限单元法对某高速公路下伏一多层倾斜复杂地质条件老采空区的变形与稳定性进行了数值模拟。模拟计算结果表明,研究区多层倾斜采空区对路基的危害性严重,必须对公路路基影响范围内的采空区部位进行处治。     

Lubricated squeezing flow of a Newtonian liquid between elastic and rigid plates

Theoretical force-time relationships were derived for squeezing flow of a Newtonian liquid between lubricated rigid and elastic plates. It is shown how the elastic number, representing the ratio between the elastic plate's rigidity and the specimen's viscosity, affects the force-time curve and under what circumstances the fluid specimen's thickness becomes a significant factor. Potential implications of the analysis in oral sensory evaluations of viscous foods are also considered.     

气相色谱仪灵敏度及检测限的测量不确定度评定

按JJF1059-1999《测量不确定度评定与表示》和JJG700-1999《气相色谱仪检定规程》评定了气相色谱仪检测器灵敏度或检测限测量的不确定度。给出了评定灵敏度及检测限的测量不确定度数学模型,并对各不确定度分量进行了评定。浓度型检测器灵敏度或检测限的相对扩展不确定度均为4.4%(k=2),质量型检测器检测限的相对扩展不确定度为3.8%(k=2)。依据JJF1033-2008《计量标准考核规范》采用比对法验证了灵敏度和检测限测量不确定度的合理性。     

Construction and evaluation of a novel end-column amperometric detection system for electrophoresis microchips

A set of integrated end-column amperometric detection system has been developed,onto which an electrophoresis microchip can be conveniently integrated.Finely machined by a piece of transparent organic glass,the system consists of an electrophoresis microchip platform and an amperometric detection reservoir,in which the microchip can be fixed onto the platform by microchip grooves and with stainless steel fixture.Each detection electrode can be directly fixed in the amperometric detection reservoir by screws...     

Characterization and de novo sequencing of snow crab tropomyosin enzymatic peptides by both electrospary ionization and matrix‐assisted laser desorption ionization QqToF tandem mass spectrometry

The protein tropomyosin (TM) is a known major allergen present in shellfish causing frequent food allergies. TM is also an occupational allergen generated in the working environment of snow crab (Chionoecetes opilio) processing plants. The TM protein was purified from both claw and leg meats of snow crab and analyzed by electrospray ionization and matrix‐assisted laser desorption/ionization (MALDI) using hybrid quadruple time‐of‐flight tandem mass spectrometry (QqToF‐MS). The native polypeptide molecular weight of TM was determined to be 32 733 Da. The protein was further characterized using the ‘bottom‐up’ MS approach. A peptide mass fingerprinting was obtained by two different enzymatic digestions and de novo sequencing of the most abundant peptides performed. Any post‐translational modifications were identified by searching their calculated and predicted molecular weights in precursor ion spectra. The immunological reactivity of snow crab extract was evaluated using specific antibodies and allergenic reactivity assessed with serum of allergic patients. Subsequently, a signature peptide for TM was identified and evaluated in terms of identity and homology using the basic local alignment search tool (BLAST). The identification of a signature peptide for the allergen TM using MALDI‐QqToF‐MS will be critical for the sensitive and specific quantification of this highly allergenic protein in the work place. Copyright © 2010 John Wiley & Sons, Ltd.     

Chemical markers’ fishing and knockout for holistic activity and interaction evaluation of the components in herbal medicines

A strategy based on chemical markers’ fishing and knockout has been proposed for holistic activity and interaction evaluation of the bioactive components in herbal medicines (HMs). It was devised to screen bioactive-compound group that represents the efficacy of HM, estimate the bioactivity contribution of each component and elucidate the interactions of multi-components. This strategy was accomplished through the following steps: (1) screen out the chemical markers (target peaks) in a HM fingerprint using online two-dimensional turbulent flow chromatography/liquid chromatography–mass spectrometry technique, (2) fish target peaks and knockout any interested peak, and (3) evaluate the bioactivities of fishing and knockout portions. After comparison of the bioactivities of samples containing different target peaks, the efficacy of target-peak group, bioactivity contribution of each compound, and the interactions of multi-components are elucidated. Using Acetylcholinesterase (AChE) and Bulbs of Lycoris radiata (L. Herit.) Herb. (BLR) as the experimental materials, four target peaks were screened out as the AChE binders. By target peaks’ fishing and knockout, combined with activity evaluation, we observed that the bioactivity of the four-peak mixture is similar with the global bioactivity of BLR extract, and there are significant suppressive actions among these four target peaks. These results indicate that this proposed strategy is a useful approach for holistic screening of bioactive-compound group and elucidation of the multi-component interactions in HM.     

点阵式上转换板在激光光斑采集中的应用研究

 通过在镜头前加装上转换板,利用其快速的红外上转换功能可以提高CCD对于低频窄脉冲光斑的采集效率。然而在利用传统面阵式工艺制成的上转换板采集光斑的过程中,普遍存在因上转换材料内部漫反射及局部饱和效应造成的光斑形状和光强分布的失真。针对上述问题,提出了一种新的点阵式上转换板制作工艺,并设计了点阵式上转换板光斑采集成像质量对比实验。实验结果表明,点阵式上转换板对低频窄脉冲光斑有更好的采集效果。为评价点阵式上转换板所采集光斑的成像质量,建立了相应的评价模型。