基于参数标准化的单样本定标方法在微波等离子体炬水泥快速分析中的应用

流程工业颗粒物成分的在线检测具有低延时、安全可靠及低成本等要求,目前没有适合的技术手段.微波等离子炬(Microwave plasma torch,MPT)原子发射光谱法具有直接进样、成本低及装置安全可靠等优点,有潜力成为工业在线检测的重要手段.本文基于MPT装置对水泥样品进行直接进样分析,并针对工业应用场景中标准样品受限的问题,采用单样本定标技术(Single sample calibration,SSC)进行定量分析.SSC法中的线性假设容易受到等离子体参数波动的影响,导致精度下降.为此,提出了一种基于参数标准化的SSC算法PS-SSC(SSC based on parameter standardization),通过激发温度和电子数密度对谱线强度进行修正以提高SSC的定量精度.为了评估MPT和PS-SSC方法联用在水泥成分快速分析中的有效性,将GSB 08-2985-2013标准水泥粉末气溶胶直接引入MPT中进行定量分析,并将PS-SSC与现有定量方法进行比较.与传统SSC方法相比,PS-SSC方法的决定系数R2由‒0.81~0.81提高到0.39~0.88,平均相对误差由4.39%~10.33%提高到1.55%~5.83%,平均相对标准偏差由2.89%~9.40%提高到2.28%~6.50%,展现了该方法在工业在线成分检测中的应用潜力.

关于计量标准样本检定问题

本文根据多年来国内进行的计量标准样本（以下简称标样）检定情况，提出了开展标样检定时．方案的确定、项目和标样的选择、检定结果的评定以及开展此项工作的意见等。

改进的LLGC高光谱图像半监督分类

针对高光谱数据波段多,地物标签获取代价高,带标记的样本数量少,分类过程中容易引起Hudges现象。本文提出一种基于改进的局部全局一致性(learning with local and global consistency,LLGC)算法的半监督分类方法。通过边缘采样法(margin sampling,MS)选取最富含信息量的无标签样本,加入到训练集来扩充训练样本;用KNN算法计算相似度进一步优选无标签样本,去除噪声点和存在的野值点;使用改进的局部全局一致性算法对无标签样本集进行分类标记,得到各类别的分类结果。实验结果表明,本文方法在充分利用无标签样本的情况下,有效地提高了带有少量标签样本的高光谱图像的分类精度。

Effect of sample treatment on determination of arsenic （Ⅲ） and arsenic （Ⅴ） in aqueous and tissue samples by hydride generation atomic absorption spectrometry

The purpose of this procedure was to optimize and improve a method that used for the determination of arsenic （Ⅲ） and arsenic （Ⅴ） in biological and environmental samples. The method is based on hydride generation and atomic absorption spectrometry. For both As （Ⅲ） and As （Ⅴ） the parameters such as NaBH4, HCI concentration, and pH were optimized. Absorption signal of As （Ⅴ） was approximately 17% of As （Ⅲ） signal. Therefore, for estimation of As （Ⅲ） and As （Ⅴ） concentrations in various samples the difference between the absorbance obtained for arsenic, without and with previous treatment of samples with potassium iodide （KI）, can be applied. The calibration graphs were linear （r〉0.99）, and the detection limits of the method based on three times the standard deviation of the blank were 0.14 and 0.64 μL^-1 for As （Ⅲ） and As （Ⅴ）, respectively. The relative standard deviation （R.S.D.） of measurements was less than 10%. As a means of checking performance method, water samples were spiked with known concentrations of both As （Ⅲ） and As （Ⅴ）, and recovery above 94% was obtained. The proposed method was applied successfully to determine inorganic As （Ⅲ） and As （Ⅴ） in various environmental and total As in biological samples.

Organizational Environment and Work Satisfaction of the Employees of Hitachi Chemical Montemorelos Nuevo Leon México

This study seeks to answer one question： The quality level of organizational environment. Is it an indicator of the workplace satisfaction level, according to the perception of Hitachi Chemical employees in Montemorelos, Nuevo León, México？ This study＇s design is both explanatory and cross-sectional. The sample size was composed of 143 Hitachi Chemical employees of Montemorelos, Nuevo León, México. For the data collection, two instruments were used： the first instrument was used to measure the quality of organizational climate and the second was focused on measuring the workplace satisfaction level. As a result, the level of organizational climate quality is in fact a predictor of workplace satisfaction of Hitachi Chemical employees. After the regression analysis, it was found that the variable, level of organizational climate, explained a 71.4% variance in the dependent variable, work satisfaction. It was determined that organizational climate is a strong predictor of work satisfaction perceived by employees of Hitachi Chemicals, Montemorelos, Nuevo León, México. It can be established that the greater the levels of organizational climate experienced by the employees, the greater the level of work satisfaction will be.

Cracks coalescence mechanism and cracks propagation paths in rock-like specimens containing pre-existing random cracks under compression

The mechanism of cracks propagation and cracks coalescence due to compressive loading of the brittle substances containing pre-existing cracks （flaws） was modeled experimentally using specially made rock-like specimens from Portland Pozzolana Cement （PPC）. The breakage process of the specimens was studied by inserting single and double flaws with different inclination angles at the center and applying uniaxial compressive stress at both ends of the specimen. The first crack was oriented at 50＆#176; from the horizontal direction and kept constant throughout the analysis while the orientation of the second crack was changed. It is experimentally observed that the wing cracks are produced at the first stage of loading and start their propagation toward the direction of uniaxial compressive loading. The secondary cracks may also be produced in form of quasi-coplanar and/or oblique cracks in a stable manner. The secondary cracks may eventually continue their propagation in the direction of maximum principle stress. These experimental works were also simulated numerically by a modified higher order displacement discontinuity method and the cracks propagation and cracks coalescence were studied based on Mode I and Mode II stress intensity factors （SIFs）. It is concluded that the wing cracks initiation stresses for the specimens change from 11.3 to 14.1 MPain the case of numerical simulations and from 7.3 to 13.8 MPa in the case of experimental works. It is observed that cracks coalescence stresses change from 21.8 to 25.3 MPa and from 19.5 to 21.8 MPa in the numerical and experimental analyses, respectively. Comparing some of the numerical and experimental results with those recently cited in the literature validates the results obtained by the proposed study. Finally, a numerical simulation was accomplished to study the effect of confining pressure on the crack propagation process, showing that the SIFs increase and the crack initiation angles change in this case.

Mechanical behavior and failure analysis of brittle sandstone specimens containing combined flaws under uniaxial compression

Based on the axial stress-axial strain curves,the effect of fissure angle on the strength and deformation behavior of sandstone specimens containing combined flaws is analyzed.The mechanical parameters of sandstone specimens containing combined flaws are all lower than that of intact specimen,but the reduction extent is distinctly related to the fissure angle.The results of sandstone specimens containing combined flaws are obtained by the acoustic emission,which can be used to monitor the crack initiation and propagation.The ultimate failure mode and crack coalescence behavior are evaluated for brittle sandstone specimens containing combined flaws.Nine different crack types are identified on the basis of their geometry and crack coalescence mechanism(tensile crack,hole collapse,far-field crack and surface spalling)for combined flaws.The photographic monitoring was also adopted for uniaxial compression test in order to confirm the sequence of crack coalescence in brittle sandstone specimens containing combined flaws,which recorded the real-time crack coalescence process during entire deformation.According to the monitored results,the effect of crack coalescence process on the strength and deformation behavior is investigated based on a detailed analysis for brittle sandstone specimens containing combined flaws by using digital photogrammetry.

An ecological perspective on Joseph Rock’s(1884-1962)plant collection activities in China

In the early 20th century,numerous western botanists,often referred to as‘plant hunters’,embarked on ambitious expeditions to China,playing a crucial role in the study of botany and botanical diversity.Despite their contributions,comprehensive assessments of their explorations are lacking.To bridge this gap,this article focuses on the work of Joseph Charles Francis Rock,a notable figure in that era.Our work revisits Rock’s botanical expeditions within the broader context of botanical diversity conservation.It outlines his historical experiences in collecting plants in China and enumerates the species composition and phenotypic traits of the plants he collected.Additionally,it also analyzes the spatial distribution of the species,the completeness of his collection and the α-and β-diversity of the plants he collected.Our findings reveal that Rock led four major botanical expeditions in China between 1922 and 1933,amassing a total of 28184 sheets and 16608 numbers across 204 families,1081 genera and 4231 species.His focus was predominantly on ornamental species,which exhibit a variety of flower colors and inflorescences.His collection work spanned 5 provinces,35 cities and 72 counties,with a notable concentration in the Hengduan Mountains,a current biodiversity hotspot.This study not only reconstructs Rock’s botanical legacy but also offers valuable historical data and fresh analytical insights for understanding contemporary plant diversity.It contributes to the ongoing discourse on the importance of preserving plant diversity as a cornerstone of environmental sustainability.

Approximate Conditional Likelihood for Generalized Linear Models with General Missing Data Mechanism

The generalized linear model is an indispensable tool for analyzing non-Gaussian response data, with both canonical and non-canonical link functions comprehensively used. When missing values are present, many existing methods in the literature heavily depend on an unverifiable assumption of the missing data mechanism, and they fail when the assumption is violated. This paper proposes a missing data mechanism that is as generally applicable as possible, which includes both ignorable and nonignorable missing data cases, as well as both scenarios of missing values in response and covariate.Under this general missing data mechanism, the authors adopt an approximate conditional likelihood method to estimate unknown parameters. The authors rigorously establish the regularity conditions under which the unknown parameters are identifiable under the approximate conditional likelihood approach. For parameters that are identifiable, the authors prove the asymptotic normality of the estimators obtained by maximizing the approximate conditional likelihood. Some simulation studies are conducted to evaluate finite sample performance of the proposed estimators as well as estimators from some existing methods. Finally, the authors present a biomarker analysis in prostate cancer study to illustrate the proposed method.

Is there a relationship between length of resection and lymph-node ratio in colorectal cancer?

Background:The prognosis of colorectal cancer depends on the number of positive lymph nodes(LNþ)and the total number of lymph nodes resected(rLN).This represents the lymph-node ratio(LNR).The aim of our study is to assess how the length of the resected specimen(RL)influences the prognostic values of the LNR.Methods:We conducted a retrospective study of all the patients operated on for colorectal cancer from 2000 to 2015 at our institution.Pathology details were analysed.The total number of rLN,the number of LNþ,and the LNR were calculated and measured against the RL.The receiver-operating characteristic(ROC)curve of patients with LNþwas calculated.Results:Of the 670 patients included in our study,337 were men(50.3%)and the mean age was 69.2 years.The correlation with prognosis of the LNR is greater than that of the LNR adjusted to RL(LNR/RL),both in subjects with positive nodes(n=312)and in all cases(n=670).The LNR presents a higher prognostic value than LNR/RL and RL in patients with LNþexcept for metastatic recurrence,for which the predictive value appears slightly higher for LNR/RL.The statistical significance of the maximal divergence in Kaplan–Meier survival plots was demonstrated for the LNR(P=0.043),not for LNR/RL(P=0.373)and RL alone(P=0.314).Conclusion:An increase in RL causes an increase in the number of harvested lymph nodes without affecting the number of LNþ,thus representing a confounding factor that could alter the prognostic value of the LNR.Prospective larger-scale studies are needed to confirm these findings.