气体报警器检定用智能控制终端的设计与实现

介绍了一种用于有毒有害气体报警器计量检定用手持控制终端的设计。通过对手持终端的软件、电源系统、无线通信系统和主控系统的研发,实现了无线控制报警器检定的操作,并可在手持终端上显示报警器的相关参数以及检定结果等内容。该手持终端提高了检定效率,避免了有害气体对检定人员的侵袭。     

有毒有害气体报警器检测探讨

介绍了常见有毒有害气体检测报警器的分类。对气体检测报警器的检测方法进行探讨,为此类报警器的检测方法提供建议。     

标定罩使用对气体报警器检定结果的影响

为指导检定人员在气体报警器检定时对气体标定罩的正确使用,对标准罩、大罩、小罩、不带罩4种情况进行试验,并对气体报警器检定结果的绝对误差、响应时间、重复性等参数进行对比分析。结果表明,在满足绝对误差±5%FS之内、响应时间不大于60 s、重复性不大于2%的技术指标要求时,使用标准罩能够得到更准确、稳定、符合现场模拟真实数值的检定结果。该研究有利于提高气体报警器检定结果的准确性。     

基于UWP跨平台移动式可燃气体检测报警器智能检定系统的研制

将UWP(Windows通用应用平台)技术应用于可燃气体检测报警器智能检定系统的设计,研制移动式可燃气体检测报警器智能检定系统。该系统包括移动端和PC端,移动端包括委托单信息处理、检定数据处理、数据上传、XML数据管理4个模块;PC端包括上传信息读取、委托单/证书/记录生成及打印两个模块。该系统的研制实现了检定系统在手机、平板、智能检定工作台等的跨平台应用,提高了报警器的检定效率。     

可燃气体检测报警器计量检定与计量管理的探讨

指出了可燃气体检测报警器计量检定的重要性,结合河南省南阳市辖区内可燃气体检测报警器计量检定的现状,着重分析了计量检定与计量管理存在的问题和难点,并且提出了相关建议。     

复合式气体报警器检定装置的研制

提出一种新型复合式气体报警器检定方法,根据此方法设计一套复合式气体检测报警器检定装置。该检定装置由工作柜、气瓶存储柜、气体输送气路、流量控制器、气体稀释装置、旋转工作台6部分组成。其中气体输送气路共有6路通道,气体稀释装置的重复性不大于0.5%。旋转工作台可同时对多台仪器进行测量,另外还配备了证书编辑软件。该装置检定结果的扩展不确定度不大于5%(k=2),其中:用于0~100%LEL CH4检定的扩展不确定度为3.0%(k=2);用于0~100μmol/mol H2S检定的扩展不确定度为5.0%(k=2);用于0~100μmol/mol CO检定的扩展不确定度为4.2%(k=2);用于0~20.9%O2检定的扩展不确定度为3.4%(k=2)。该检定装置工作效率高,采用PLC和上位机的控制方式能够实现检定过程自动化测量。该装置主要适用于CH4,H2S,CO,O2气体报警器的检定。     

可燃气体检测报警器检定用标准物质的选择

可燃气体检测报警器,亦称测爆仪,广泛应用于危险化学品场所中可燃性气体泄漏事故的检测报警,属于国家强制检定的工作用计量器具。JJG693-2004可燃气体检测报警器(以下简称报警器)国家计量检定规程(以下简称规程)经国家质量监督检验检疫总局于2004年3月2日批准,并自2004年9月2日     

有机玻璃雕刻过程中有害气体的3阶段预浓缩GC/MS分析

研究了3阶段预浓缩气相色谱-质谱法检测有机玻璃在雕刻过程中排放的有害气体的组成。研究结果表明,气体中含有12种以上的有机污染物。其中甲基丙烯酸甲酯、丙烯酸甲酯、苯、甲苯、苯乙烯等5种有毒有害物可以作为代表该行业特征的污染物加以监控。     

空气中偏二甲肼气体标准物质的研制

采用称量法制备空气中偏二甲肼气体标准物质,分别用F检验和回归曲线法对研制的标准物质进行均匀性和稳定性检验。结果表明,研制的空气中偏二甲肼气体标准物质具有良好的均匀性和稳定性,定值结果分别为10,500μmol/mol,定值结果的相对扩展不确定度为2%(k=2)。该标准物质可用于偏二甲肼报警器的检定或校准。     

常用气体报警器的工作原理、性能及应用

按照常用气体报警器的分类,系统分析了每种报警器的工作原理、工作性能及应用范围,介绍了常用气体报警器在国内外的发展状况.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.