Proficiency test for effective area determination of a pneumatic pressure balance in Mexico

A pneumatic pressure proficiency test for effective area determination of a pressure balance was performed among 4 accredited calibration laboratories in Mexico. CENAM provided the reference values (making initial and final calibrations) and was the pilot laboratory. The Mexican Accreditation Entity (ema) collaborated. The participants calibrated, by cross floating, a Wika pressure balance model CPB 5000 with accuracy class 0.015% of the reading in the range 0.7–7 MPa. The calibration pressures were 0.7, 1.4, 2.1 3.5, 4.2, 5.6 and 7.0 MPa. For A₀ and A_e, the normalized error equation was used to compare the results of the laboratories with CENAM’s reference values. The results obtained were satisfactory (E_n did not exceed the compatibility limit, −1 ⩽ E_n ⩽ 1).     

凸椭圆上车三角异型螺纹

运用宏程序分析了在凸椭圆轮廓上车削三角异型螺纹的编程和加工方法。     

顶空-气相色谱法及其在胶粘剂有机残留测定中的应用

顶空-气相色谱法作为一种符合"绿色分析化学"要求的分析手段,近年来引起人们广泛的研究兴趣。简要介绍了顶空-气相色谱技术及其在胶粘剂有机残留测定中的应用,并对其应用前景进行展望。     

Image Space Rendering of Point Clouds Using the HPR Operator

The hidden point removal (HPR) operator introduced by Katz et al. [KTB07] provides an elegant solution for the problem of estimating the visibility of points in point samplings of surfaces. Since the method requires computing the three‐dimensional convex hull of a set with the same cardinality as the original cloud, the method has been largely viewed as impractical for real‐time rendering of medium to large clouds. In this paper we examine how the HPR operator can be used more efficiently by combining several image space techniques, including an approximate convex hull algorithm, cloud sampling, and GPU programming. Experiments show that this combination permits faster renderings without overly compromising the accuracy.     

基于语义相似度的Web信息可信分析

互联网上的虚假事实陈述严重影响人们有效地获取信息,如何判定事实陈述是否可信成为一个亟待解决的问题.文中提出了一种针对事实陈述的可信判定模型MFSV.该模型针对事实陈述的特点,从互联网上搜集与待判定事实陈述相关的文本信息,度量其与对应事实陈述的语义相似度;同时,该模型考虑了相关文本信息在可信度上的差别,从受欢迎程度和重要程度两个方面度量了相关文本信息来源的可信度,并获取了相关文本信息的可信度排序;根据语义相似度以及可信度排序,衡量了相关文本信息对对应事实陈述可信判定所做出的贡献,并以此为基础实现了待判定事实陈述的可信判定.一系列的实验验证了该模型的合理性及可信判定的准确性.     

钨精矿中钡、锶含量的连续测定

研究了火焰原子吸收光谱仪连续测定钨精矿中钡、锶含量的方法。试样经碳酸钠—过氧化钠熔融,熔融物用硝酸溶液提取,在仪器最佳工作条件下,快速、准确地连续测定钨精矿中钡、锶含量。实验表明该方法操作简便,灵敏度高,干扰少,钡的回收率为94.2%～96.3%;锶的回收率为94.0%～102.5%。     

A sparse nonparametric hierarchical Bayesian approach towards inductive transfer for preference modeling

In this paper, we present a novel methodology for preference learning based on the concept of inductive transfer. Specifically, we introduce a nonparametric hierarchical Bayesian multitask learning approach, based on the notion that human subjects may cluster together forming groups of individuals with similar preference rationale (but not identical preferences). Our approach is facilitated by the utilization of a Dirichlet process prior, which allows for the automatic inference of the most appropriate number of subject groups (clusters), as well as the employment of the automatic relevance determination (ARD) mechanism, giving rise to a sparse nature for our model, which significantly enhances its computational efficiency. We explore the efficacy of our novel approach by applying it to both a synthetic experiment and a real-world music recommendation application. As we show, our approach offers a significant enhancement in the effectiveness of knowledge transfer in statistical preference learning applications, being capable of correctly inferring the actual number of human subject groups in a modeled dataset, and limiting knowledge transfer only to subjects belonging to the same group (wherein knowledge transferability is more likely).     

乙二胺四乙酸四钠中杂质铁的测定

对乙二胺四乙酸四钠中的铁测定,目前主要有两种方法：火焰原子吸收分光光度法和1,10-菲罗琳法。绝大多数用户都采用简便易测的火焰原子吸收分光光度法,但此种方法在不扣除背景的情况下测定结果会因仪器而异。文章通过两台不同型号原子吸收分光光度仪（美国PE-AA100和上海HP-3510）的实验对比表明,在PE-AA100中铁的测定中存在背景吸收,需校正背景,而HP-3510无背景吸收,可直接检测出准确数据。     

提高SnCl_2-TiCl_3-K_2Cr_2O_7法测定铁矿石中全铁含量可操作性的探讨

近年来,我国钢铁工业的迅猛发展,钢铁工业领域的技术也精益求精,不断要求着从业者在自己领域不断发展同时不断创新跟上行业发展的步伐。钢铁企业为了更好的满足社会的需求,需要不断的加大自身的生产能力,而铁矿石作为钢铁行业中最重要的基础原料,所以对铁矿石的需求也越来越大。在进行铁矿石的贸易过程中,随之而来的问题就是对铁矿石进行检测,以确保其含量达标。     

Cloud Point Extraction and Spectrophotometric Determination of Sulfide in Water Samples using Ethylene Blue Formation Reaction

Abstract

A rapid, selective, and sensitive cloud point extraction process using mixed micelle of a nonionic surfactant, Triton X-114, and an anionic surfactant, SDS, to extract sulfide from aqueous solutions was investigated. The method is based on the color reaction of sulfide with N,N-diethyl-p-phenylenediamine (DPD) in the presence of suitable oxidizing reagent (Fe³⁺) in acid media and cloud point extraction of ethylene blue (EB) dye. Various factors and optimal extraction and reaction conditions like: acid, Fe³⁺, reagent, and surfactant concentration were studied and the analytical characteristics of the method (e.g., limit of detection, linear range, RSD%) were obtained. Linearity was obeyed in the range of 1–100 ng mL^?1 of sulfide ion. The detection limit of the method is 0.5 ng mL^?1 of sulfide ion. The interference effect of some anions, cations, and neutral species was also tested. The method was applied to the determination of sulfide in spring, river, and waste water samples.