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以探寻二氧化碳的工业捕集方案为项目主题,开展初中化学二氧化碳的性质及其转化的教学。学生通过“建立价类二维模型并设计二氧化碳的理想转化路径”“实验探究二氧化碳的实际转化”“解决二氧化碳的工业转化”等3个项目子任务理解了物质“组成、性质、变化”之间的关系,运用手持技术数字化实验探究了二氧化碳在不同碱溶液中的吸收效率,发展了实验探究能力,构建了物质转化在化工生产领域的认知模型,提高了思维迁移的能力。从“碳捕集”到“碳利用”的进阶解决问题模式,有利于学生化学学科核心素养的内化。 相似文献
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微藻生物固碳技术进展和发展趋势 总被引:1,自引:0,他引:1
大气中CO2含量升高是导致温室效应的主要原因,因此,减少CO2的排放和积累是解决全球气候变暖的重点.传统的CO2减排方法包括捕集(capture)和储存(storage),涉及化学吸附、物理吸收、膜分离和低温蒸馏等一系列物理化学方法,但其均存在成本高和不可再生等缺点.通过种植或养殖生物质可以捕集CO2.微藻生长周期短、光合效率高,其CO2固定效率为一般陆生植物的10~50倍;同时微藻生长速度快,能利用不可耕地,具有广阔的发展前景.本文概述了适用的藻种及所能达到的CO2固定效果,分析了光生物反应器类型、光照强度、光周期、温度、pH、CO2浓度、CO2吸收效率、气体传质效率和营养需求(包括来自市政和工业农废水中的N、P等营养)等多种因素对微藻固碳效果的影响.最后,对微藻固碳的实际应用和经济可行性进行了评估,展望了微藻固碳技术的发展和应用前景. 相似文献
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《化学分析计量》2018,(1)
本发明提供了一种利用磁控技术提高金刚石薄膜微波等离子体化学气相沉积设备沉积速率的方法和装置。该方法包含以下步骤:在微波等离子体化学气相沉积工艺中利用磁场形成电子捕集阱,电子在捕集阱的约束下,在衬底上方固定区域作封闭的曲线运动,电子在运动过程中碰撞反应气体碰撞生成前驱反应基团和石墨组织抑制基团,从而提高反应基团浓度,实现金刚石薄膜沉积速率的提高。使用该方法的反应腔装置由微波源、螺钉调配器、定向耦合器、同轴天线、波导装置、调节活塞、谐振腔、石英罩、磁场发生装置等组成。本发明优点是可以显著提高金刚石微波等离子体化学气相沉积工艺的薄膜沉积速率,工艺和装置简单,便于实施。 相似文献
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原子捕集原子吸收光谱法测定铅 总被引:5,自引:2,他引:5
原子捕集技术首先由Stphens提出,West等人进行了系统研究。作者对这一技术作过评述和研究。原子捕集是一种在火焰原子吸收测量中浓缩待测原子的预富集技术。与溶剂萃取或离子交换等常规预富集方法比较,原子捕集技术具有明显优点:不必加入化学试剂,省去样品溶液的制备时间,避免试样的化学前处理或化学预浓缩操作中的污染或损失,节省分析时间,提高分析灵敏度和准确度。 相似文献
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化学吸收法是碳捕集技术中最为成熟的技术之一,单乙醇胺(MEA)是最常用的化学吸收剂.然而由于MEA的解吸能耗较高,造成CO_2捕集成本居高不下.本文提出了一种利用盐析效应开发新型CO_2相变化吸收剂的方法,并开发了吸收剂组成为"MEA+叔丁醇+水"的新型CO_2相变化吸收剂.实验考察了不同配比下吸收剂的分相情况、循环负载量以及吸收剂的物理性质,并用气相容积法测定了40℃、0~0.5 MPa下,CO_2在相变化吸收剂中的溶解度.研究表明,MEA/叔丁醇相变化吸收剂的循环负载量最高为2.84 mol CO_2/kg,相比于30%MEA水溶液提高了40%,进入解吸塔的吸收剂体积降低了65%,有望大幅降低CO_2捕集能耗. 相似文献
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在测定水中微量的挥发性有机物时,常利用吹扫-捕集技术对水样进行预处理,以浓缩分离待测物质,使其达到后续分析仪器的检测限值。吹扫-捕集装置通常价格昂贵,难以在分析化学、环境监测等实验教学中普遍配备。介绍了一套经过改造的简易吹扫-捕集装置,用以展示其工作原理。改造后的吹扫-捕集装置以低温有机溶剂捕集代替了原常规装置中的吸附剂捕集,简化了实验流程。对水中甲基叔丁基醚(MTBE)的预处理实验结果表明,该装置操作简单,原理展示清晰,实验数据相对精确,可有效加强学生对吹扫-捕集技术的理解。 相似文献
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把二元溶液的过剩内能(excess energy)分成溶剂-溶剂、溶剂-溶质及溶质-溶质相互作用部分。利用集团展开方法给出了二元溶液在正则系综的配分函数的表达式,利用该表达式得到了溶质的偏摩尔内能(partial molar energy)和偏摩尔熵(partial molar entropy)的表达式。在无限稀溶液情形,过剩偏摩尔内能的溶剂-溶剂部分又称重组织内能(reorganization energy),它反映了溶质存在时对其周围溶剂分子之间的相互作用能的影响。研究表明,在溶质的粒子数密度相对较大时,溶质分子之间的相互作用将影响过剩偏摩尔内能的溶剂-溶剂部分,对于稀溶液,过剩偏摩尔内能的溶剂-溶剂部分与溶质的摩尔分数成线性关系。对低密度二元溶液,溶质的过剩偏摩尔内能和过剩偏摩尔熵也与溶质的摩尔分数成线性关系。 相似文献
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Advanced additive manufacturing actively widens its tool box of wettability-related phenomena to be used in production of new items. Novel self-healing engineering materials incorporate vascular networks with two types of nanochannels: the one containing a resin monomer, whereas another one — a curing agent. If such nanocomposites are damaged locally, both types of channels are locally broken, and they release resin monomer and curing agent droplets. These droplets spread by wettability over the nanotextured matrix, touch each other, and coalesce, which triggers polymerization reaction and crack stitching. Wettability-facilitated droplet spreading is accompanied by liquid imbibition in the pores in the nanofiber network. Such process peculiarities are in focus in the present review. An additional process relevant in direct writing and 3D printing is electrowetting (EW). It stems from the change in the contact angle in response to the electric polarization of dielectric substrates. EW allows movement of droplets on horizontal, vertical, and inverse surfaces, which can significantly facilitate the existing direct writing and 3D printing technologies. Accordingly, EW is also in focus in the present review. 相似文献
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Günter Gauglitz 《Accreditation and quality assurance》2010,15(2):137-137
News and Announcements
Call for nominations for the Heinrich-Emanuel-Merck Award 相似文献16.
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Chiara Mazzoni Rasmus Due Jacobsen Jacob Mortensen Jacob Rune Jrgensen Lukas Vaut Jette Jacobsen Carsten Gundlach Anette Müllertz Line Hagner Nielsen Anja Boisen 《Macromolecular bioscience》2019,19(5)
Oral delivery of proteins and peptides is one of the main challenges in pharmaceutical drug development. Microdevices have the possibility to protect the therapeutics until release is desired, avoiding losses by degradation. One type of microdevice is polymeric microcontainers. In this study, lysozyme is chosen as model protein and loaded into microcontainers with the permeation enhancer sodium decanoate (C10). The loaded microcontainers are sealed and functionalized by applying polymeric lids onto the cavity of the devices. The first lid is poly(lactic‐co‐glycolic) acid (PLGA) and on top of this either polyethylene glycol (PEG) or chitosan is applied (PLGA+PEG or PLGA+chitosan, respectively). The functionalization is evaluated in vitro for morphology, drug release, and mucoadhesive properties. These are coupled with in vitro and ex vivo studies using Caco‐2 cells, Caco‐2/HT29‐MTX‐E12 co‐cultures, and porcine intestinal tissue. PLGA+chitosan shows slower release compared to PLGA+PEG or only PLGA in buffer and the transport of lysozyme across cell cultures is not enhanced compared to the bulk powder. Microcontainers coated with chitosan or PEG demonstrate a three times stronger adhesion during ex vivo mucoadhesion studies compared to samples without coatings. Altogether, functionalized microcontainers with mucoadhesive properties and tunable release for oral protein delivery are developed and characterized. 相似文献
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Kernel density estimation is a method for producing a smooth density approximation to a dataset and avoiding some of the problems associated with histograms. If it is used with a degree of smoothing determined by a fitness for purpose criterion, it can be applied to proficiency test data in order to test for multimodality in the z-scores. The bootstrap is an essential additional technique to determine how rugged the initially estimated kernel density is: the random resampling of the data in the bootstrap simulates a complete blind repeat of the proficiency test. In addition, useful estimates of the standard error of a mode can be thus obtained. It is suggested that a mode and its standard error can be used as an assigned value and its standard uncertainty. 相似文献
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Bradley W. Popovich 《Accreditation and quality assurance》2002,7(8-9):351-356
Nucleic acid based clinical genetic testing has undergone explosive growth in recent years due in large part to the human
genome project. Characterization of the human genome has led to a molecular understanding of the pathogenesis of many human
diseases, and ultimately to clinical molecular tests becoming routinely used to diagnose a wide diversity of diseases. This
rapid growth in clinical molecular genetic testing coupled with the complexity of the analytical procedures underscores the
necessity for proficiency testing (i.e. external quality assessment) to allow laboratories offering such services the ability
to evaluate their analytical procedures via inter-laboratory comparisons. The American College of Medical Genetics (ACMG)
in partnership with the College of American Pathologists (CAP) have been offering proficiency testing for clinical molecular
genetics laboratories since 1995, and presently have more than 230 laboratories from 11 countries enrolled in this program.
This paper describes the evolution of this program and several challenges encountered in the delivery of a proficiency testing
program for laboratories offering clinical molecular genetic services.
Received: 13 April 2002 Accepted: 18 July 2002 相似文献
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《Radiation Physics and Chemistry》2009,78(9):782-790
Spectrometer settings for ESR readout of alanine dosimeters for radiotherapy have been investigated. Several ESR parameters were studied and determined. The main reason for this work is to choose the suitable parameters to increase signal-to-noise ratio and to reduce the uncertainty on ESR readout, which is one of the main components of uncertainty of alanine/ESR dosimetry system for radiotherapy. The new spectrometer settings have been applied for ESR readout of alanine dosimeters irradiated from 1 to 10 Gy. A higher signal-to-noise ratio has been achieved compared to our old spectrometer settings. The extended uncertainty (k=2) has been evaluated in the dose range 2–10 Gy (maximum uncertainty of 4.9% for 2 Gy, while minimum uncertainty of 1.4% for 10 Gy), which implies that the alanine/ESR dosimetry system can be applied to radiotherapy dose level that needs a global accuracy of 5%. 相似文献