分析化学教材中t检验内容的探讨

t检验是显著性检验的一种,在分析数据的评价、分析方法的筛选、样品质量的监测中都能发挥重要作用。从形式上,t检验可以分为与标准值的比较、配对t检验和非配对t检验。但在国内通用的普通高等学校分析化学教材中,有关t检验的内容篇幅较少,只是简单介绍了基本概念和非配对t检验。相比之下,国外的分析化学教材通过丰富的实例将这一部分内容讲解得更为生动透彻,易于学生掌握与理解。本文结合国内外教材,阐述t检验的重要性和实用性,提出分析化学学科特色应融入更系统完整的统计学内容的观点,为建设更具科学性的分析化学教材提供建议和思路。     

基于思维模型建构的“物质检验”初中复习教学研究

以让学生自主建构物质检验的思维模型为目标设计教学,通过完成物质检验的探究任务,学生自主建构思维模型,形成完整的思路,从而提高解决此类问题的能力。并在北京某中学初三年级进行教学实践,对教学实施效果进行了检验,根据教学实践总结出建构“物质检验”思维模型教学的有效教学策略：基于建模历程与生活情境选择素材;以学生为中心自主建构“物质检验”思维模型,引导学生经历多样化的思维发展过程;学生经历不同层级进阶的模型建构历程。     

硫代硫酸钠标准溶液配制中标定基准物质的优化选择

对硫代硫酸钠标准溶液配制实验中不同基准物质的标定效果进行了对比研究,结合试剂用量、反应时间、显著性检验等分析说明不同基准物质所产生的结果:重铬酸钾、碘酸钾、溴酸钾均可实现对硫代硫酸钠溶液的标定。其中溴酸钾作为标定的基准物质时,试剂用量少,反应时间短,实验费用低且终点易于观察。双侧t检验符合统计学要求,更适用于硫代硫酸钠溶液标定,有望引入学生实验。     

标准物质均匀性检验剖析

粉末混合物、矿石、合金等固体物质本身是不均匀的。因此,由这些物质制备的标准物质在分装成最小包装单元之后必须经过检验以评价均匀度。 均匀性,这一术语在ISO指南30:1992(E/F)《标准物质常用术语及定义》中是这样描述的:“对于物质的一种或多种指定特性具有相同结构或组分的一种状态。不论样品是否取自同一包装单元(如:瓶、包等),通过检验具有规定大小的样品,若被测定特     

指纹中生活特征成分检验方法研究进展

指纹是犯罪现场最常见到的汗液斑形式。目前对其进行的分析仍多局限于形态学描述和DNA检验。指纹中含有多种内源性和外源性物质,其中蕴含着遗留者的生物特征、社会习性等相关信息。通过检验指纹中的生活特征成分,可对指纹遗留者进行刻画,从而为侦查提供线索。这种技术在无法通过指纹进行个体识别时有更加重要的意义。本文总结了指纹中含有的生活特征成分,并概述了相关检验方法的研究进展。在不久的将来,相关技术一定会在案件侦查中发挥重要作用。     

血脂生化检验中采用分级检验方法的检验效果观察

目的研究并探讨在血脂生化检验中采用分级检验方法的检验效果。方法选取2014年1月—2016年12月期间温州医科大学检验学院、生命科学学院实验室收集的160份血液标本作为研究对象,采取数字随机分组法随机分为两组,每组80份血液标本,对照组血液标本采用传统拉网式检验方法进行检测,观察组血液标本采用分级检验方法进行检测,比较两组血液标本的血脂生化检验结果。结果两组血液标本经血脂生化检验后,其总胆固醇、甘油三酯、高密度脂蛋白胆固醇比较,差异均无统计学意义(P0.05),但观察组的低密度脂蛋白胆固醇、载脂蛋白A-1、载脂蛋白B与对照组比较具有统计学差异(P0.05);阳性率方面,两组总胆固醇、甘油三酯、高密度脂蛋白胆固醇的阳性率比较无统计学差异(P0.05),而观察组低密度脂蛋白胆固醇、载脂蛋白A-1、载脂蛋白B的阳性率均高于对照组(P0.05)。结论在血脂生化检验中采用分级检验方法可有效提高血脂异常的检出率,有利于提高血脂生化检验的准确性。     

多模态教学模式在“食品理化检验”中的应用

基于学生自主学习能力的培养,为更好地帮助并引导学生理解晦涩难懂、枯燥抽象的知识点,以我校卫生检验与检疫专业65名学生为研究对象,将食品理化检验课程的部分章节内容采用多模态教学模式,其余内容采用传统讲授教学模式,课程结束后使用统一问卷进行调查,对多模态教学效果进行评价。结果表明2种教学模式在理解抽象实验技术或仪器、活跃课堂气氛、拓宽学习思路以及培养学习兴趣、自主学习能力和解决实际问题能力等方面均有统计学差异(p＜0.05),且有95%的学生建议继续采用多模态教学模式。教学实践及其效果评价证明多模态教学对理解抽象问题等有一定的促进作用,并可唤起学生学习兴趣、培养学生解决实际问题的能力、拓宽学习思路等。     

钛合金光谱分析用标准物质的均匀性检验

介绍钛合金光谱分析用标准物质均匀性检验的抽样、测试、检验及判断方法。钛合金光谱分析用标准物质中碳和铝的均匀性检验结果表明此两种元素在试样中的分布是均匀的。该方法已应用于钛合金光谱分析用标准物质的研制过程中。     

检测调味料中罂粟碱壳成分的样品制备方法的改进

正在日常监管中,食品理化检验主要包括质量检验和安全性检验,其中质量检验主要针对的是食品中品质指标、污染物指标和带入或者工艺衍生的风险性指标;安全检验主要针对的是食品中可能存在的风险物质、超范围添加成分和非食用物质等方面的内容。两类检验均存在检测指标分布不均一、检测浓度范围宽泛、检测对象多样、目标物质存在基体多样性等特点。通常食品检测的不确定度来源主要     

临床检验量值溯源及其标准物质的研究现状

介绍临床检验量值溯源及标准物质在临床检验领域的重要性与必要性,比较了国内外临床检验用标准物质及临床参考系统的研究现状。建议国家应投入资金,研制更多的高等级临床用标准物质,建立较完整的临床检验溯源体系,提高国际互认能力并降低重复测量费用。     

t,F显著性检验应用中的一个问题

文章就ｔ，Ｆ显著性检验在同一个问题上检验判断的不一致性，提出在对一种分析结果（或测试结果）实施鉴定时，有必要同时进行ｔ，Ｆ的联合检验，而只有当联合检验一同被接受之后，所作用出的判定结论才是完整和可信赖的。     

Rheological and transport properties of sulfonated polyacrylamide hydrogels for water shutoff in porous media

In this research, an optimal hydrogel, based on sulfonated polyacrylamide, was synthesized by statistical design of experiments using central composite method. This new hydrogel composed of sulfonated polyacrylamide (AN125VLM) and chromium triacetate as copolymer and crosslinker, respectively. The bottle and rheological tests were conducted to investigate the gelation time, thermal stability, gel strength and also ultimate elastic modulus, complex modulus, and yield stress. It was found that copolymer concentration had the main effect in both rheological and transport properties of hydrogels. The sample prepared at optimum condition, i.e. copolymer concentration of 26,340 ppm and crosslinker/copolymer ratio of 0.12, had an ultimate elastic modulus of 29.9 kPa, yield stress of 800 Pa, and complex modulus of 32 kPa. A coreflooding test through fracture was carried out to examine the optimum gel performance in a porous media. A value of 483 for the residual resistance factor ratio of water to oil confirmed the high ability of the hydrogel in reducing the relative permeability of water to oil in fractured media. Copyright © 2014 John Wiley & Sons, Ltd.     

我国台湾学科能力测验中自然科学选择题的设置及评价

我国台湾学科能力测验自然科学的题型全部为选择题,通过增加选项数目、增加多项选择题比例、改变多项选择题编排模式、改变计分方式、改变题量与总分关系等可以减少选择题存在的强猜现象、无法考查思维过程及无法顾及学生差异性等不足,改善了选择题的考查评价功能,使考试更加公平科学,可以为我国大陆即将全面铺开的学业水平考试选择题部分的设计提供参考。     

Versatile microfluidic complement fixation test for disease biomarker detection

The complement fixation test (CFT) is a serological test that can be used to detect the presence of specific antibodies or antigens to diagnose infections, particularly diseases caused by microbes that are not easily detected by standard culture methods. We report here, for the first time, a poly(dimethylsiloxane) (PDMS)/glass slide hybrid microfluidic device that was used to manipulate the solution compartment and communication within the microchannel to establish sampler and indicator systems of CFT. Two types of on-chip CFT, solution-based and solid phase agar-based assays, were successfully demonstrated for biomarker carcinoembryonic antigen (CEA) and recombinant avian influenza A (rH7N9) virus protein detection. In addition, the feasibility of the on-chip CFT in assaying real biopsy was successfully demonstrated by specifically detecting rH7N9 and CEA in human serum. The results demonstrated that the miniaturized assay format significantly reduced the assay time and sample consumption. Exemption from protein immobilization, blocking, complicated washing steps and expensive enzyme/fluorescein conjugates highlights the merits of on-chip CFT over ELISA. Most attractively, the on-chip agar-based CFT results can be imaged and analysed by smartphone, strengthening its point-of-care application potential. We anticipate that the on-chip CFT reported herein will be a useful supplemental or back-up tool for on-chip immunoassays such as ELISA for disease diagnosis and food inspection.     

5-HT1A Serotonergic, α-Adrenergic and Opioidergic Receptors Mediate the Analgesic Efficacy of Vortioxetine in Mice

Vortioxetine is a multimodal antidepressant drug that affects several brain neurochemicals and has the potential to induce various pharmacological effects on the central nervous system. Therefore, we investigated the centrally mediated analgesic efficacy of this drug and the mechanisms underlying this effect. Analgesic activity of vortioxetine (5, 10 and 20 mg/kg, p.o.) was examined by tail-clip, tail-immersion and hot-plate tests. Motor performance of animals was evaluated using Rota-rod device. Time course measurements (30–180 min) showed that vortioxetine (10 and 20 mg/kg) administrations significantly increased the response latency, percent maximum possible effect and area under the curve values in all of the nociceptive tests. These data pointed out the analgesic effect of vortioxetine on central pathways carrying acute thermal and mechanical nociceptive stimuli. Vortioxetine did not alter the motor coordination of mice indicating that the analgesic activity of this drug was specific. In mechanistic studies, pre-treatments with p-chlorophenylalanine (serotonin-synthesis inhibitor), NAN-190 (serotonin 5-HT_1A receptor antagonist), α-methyl-para-tyrosine (catecholamine-synthesis inhibitor), phentolamine (non-selective α-adrenoceptor blocker), and naloxone (non-selective opioid receptor blocker) antagonised the vortioxetine-induced analgesia. Obtained findings indicated that vortioxetine-induced analgesia is mediated by 5-HT_1A serotonergic, α-adrenergic and opioidergic receptors, and contributions of central serotonergic and catecholaminergic neurotransmissions are critical for this effect.     

塑料多轴冲击标准与试验技术探讨

分析比较了ISO 6603-2和ASTM D3763中关于塑料多轴冲击试验方法的异同,着重讨论了这些标准在测试技术上的不同要求,探讨了试验机性能对试验结果的影响,并提出了对试验机测控系统软硬件设计的技术要求。     

以科技论文为素材的高中化学试题命制策略

命制模拟试题时,教师一般会选择化学科技论文作为试题的背景材料。通过分析近3年江苏高考化学试题,可以看出流程图题考查的基本情况。以江苏某市高考模拟化学卷为例,从4个维度阐述了以科技论文为素材的高中化学试题的命制策略：选择合适的命题背景素材;将文字内容巧妙地转化为工艺流程图;建立背景素材与试题考查之间的联系;精心设计试题设问。根据命题实践提出命制试题的关注点。     

Chemical Analysis and Toxicity Tests of Organic Pollutants in Xi River Water and Suspended Sediment of Shenyang City

Abstract

In 1987, in a 10-day investigation, two kinds of raw water and their suspended sediment samples were successively collected from the upper and middle reaches of the Xi River. The water and the suspended sediment samples were prepared by filtration of the raw water through a 0.45 μm membrane. The pH values of the water samples were adjusted to neutral (pH 6.5), basic (pH 11.0) and acid (pH 2.0) and passed through three adsorption columns filled with GDX macroreticular resin (MRR). The organic pollutants were subsequently eluted from the columns with CH₂Cl₂. Suspended sediment samples were extracted with CH₂Cl₂ by Soxhlet extraction. Organic pollutants were separated on silica gel columns and analyzed by GC and GCMS and assayed for acute toxicity, Ames test response, and micronucleus test response. Over 200 organic pollutants in the river water and the suspended sediments were determined. More than 60 main pollutants were identified according to the results of the chemical analysis and toxicity tests.     

Strain hardening test on the limits of Slow Crack Growth evaluation in high resistance polyethylene resins: Effect of comonomer type

Long term performance assessment of polyethylene pipes is an issue that has greatly increased in importance in recent years due to the incorporation in the market of high resistance to crack polyethylene grades (PE100RC), where established Slow Crack Growth (SCG) evaluation using traditional tests such as Full Notch Creep Test (FNCT) or Pennsylvania Notch Tensile (PENT) Test is insufficient. The development in recent years of fast evaluation techniques such as Strain Hardening (SH) modulus has opened an important alternative for quick SCG evaluation since it correlates well with other conventional tests such as FNCT and PENT. In this work, a large number of commercial and experimental polyethylene pipe resins with different comonomer types were evaluated in order to define their SH values to rank the resins as PE100 or PE100RC. A relationship is proposed that utilizes SH test results to estimate the SCG resistance of PE pipes. 1-Butene copolymer resins display threshold SH values of 38 and 53 MPa that have been assigned to PE100 and 100RC grades, respectively. Moreover, dependence of the SH values on comonomer type used has been demonstrated. The experimental results show that 1-hexene copolymer resins exhibit higher SH values than 1-butene comonomer based resins.     

Fabrication and characterization of functional graded polyurethane foam (FGPUF)

In this study, functionally graded polyurethane foams (FGPUFs) were produced using a layer‐by‐layer casting technique. Discontinuous FGPUFs were fabricated by this method. The scanning electron microscopy was used to study the morphology of all specimens. The mechanical properties of the polyurethane foams (PUFs) were evaluated by compression, indentation force deflection, drop weight tests, and dynamic mechanical thermal analysis. Scanning electron microscopy micrographs taken from different zones of functionally graded material showed the variation of the morphology of cells as well as the suitable interfaces between the layers of PUF. Investigation of mechanical properties suggested that FGPUF specimens have an optimum behavior between other specimens in compression and indentation force deflection tests. The results of drop weight test showed that FGPUF samples behaved like an energy absorber (14.31 KN) in comparison to other PUFs. The results of dynamic mechanical thermal analysis data showed an improvement in glass transition temperature (T_g) to −47.2°C and stability of modulus of FGPUFs as temperature increases.