分流法湿度发生器PLC控制系统的研制

采用可编程逻辑控制器(PLC)研制分流法湿度发生器的控制系统,提高了分流法湿度发生器在低湿度范围发生湿气的准确度。利用精密露点仪获得准确的露点值,并反馈控制分流法湿度发生器的各项控制参数,通过二次调节,湿度发生器可以输出湿度值更加准确的气体,发生湿气的露点最大允许误差为±0.5℃,重复性为0.15%(n=6),露点输出范围为–70~–10℃。该控制系统拓宽了分流法湿度发生器的应用范围,提高了湿度计量的工作效率。     

Protection‐Group‐Free Synthesis of Sequence‐Defined Macromolecules via Precision λ‐Orthogonal Photochemistry

An advanced light‐induced avenue to monodisperse sequence‐defined linear macromolecules via a unique photochemical protocol is presented that does not require any protection‐group chemistry. Starting from a symmetrical core unit, precision macromolecules with molecular weights up to 6257.10 g mol^?1 are obtained via a two‐monomer system: a monomer unit carrying a pyrene functionalized visible light responsive tetrazole and a photo‐caged UV responsive diene, enabling an iterative approach for chain growth; and a monomer unit equipped with a carboxylic acid and a fumarate. Both light‐induced chain growth reactions are carried out in a λ‐orthogonal fashion, exciting the respective photosensitive group selectively and thus avoiding protecting chemistry. Characterization of each sequence‐defined chain (size‐exclusion chromatography (SEC), high‐resolution electrospray ionization mass spectrometry (ESI‐MS), and NMR spectroscopy), confirms the precision nature of the macromolecules.     

Chemical-Synthesis-Based Approach to Glycoprotein Functions in the Endoplasmic Reticulum

The introduction of Asn-linked glycans to nascent polypeptides occurs in the lumen of the endoplasmic reticulum of eukaryotic cells. After the removal of specific sugar residues, glycoproteins acquire signals in the glycoprotein quality control (GPQC) system and enter the folding cycle composed of lectin-chaperones calnexin (CNX) and calreticulin (CRT), glucosidase II (G-II), and UDP-Glc:glycoprotein glucosyltransferase (UGGT). G-II initiates glycoproteins’ entry and exit from the cycle, and UGGT serves as the “folding sensor”. This account summarizes our effort to analyze the properties of enzymes and lectins that play important roles in GPQC, especially those involved in the CNX/CRT cycle. To commence our study, general methods for the synthesis of high-mannose-type glycans and glycoproteins were established. Based on these, various substrates to analyze components of the GPQC were created, and properties of CRT, G-II, and UGGT have been clarified.     

Analytical issues in monitoring drinking-water contamination related to short-term, heavy rainfall events

Heavy rainfall events, increasing in frequency and intensity with climate change, impact on the quality of the water resource used for drinking-water production. Small-scale water suppliers are particularly sensitive because of their management and the related difficulties of adapting treatment to variations. Decision-support systems, based on monitoring and analytical tools, need to be developed to improve crisis-management procedures related to such events. After presenting the issues related to heavy rainfall events, the article summarizes the tools currently used for quality control of drinking water within this framework, the need for developments and other requirements.     

Improving the interfacial property of carbon fiber/PI resin composite by grafting modification of carbon fiber surface

The poor interfacial adhesion between carbon fibers (CFs) and polyimide (PI) resin has seriously hampered the application of CF/PI composites. In this work, the interfacial adhesion was efficiently enhanced by grafting on the CF surface. Surface morphology and surface composition of modified carbon fibers were characterized, which indicated that acrylamide was grafted successfully on the CF surface and the surface roughness was increased slightly. After grafting, the interface shear strength of modified carbon fibers/PI composites was significantly improved by 86.96%, and the interlaminar shear strength was enhanced by 55.61% due to the covalent bonds in interphase and the toughening effect of sizing agent. Moreover, the mechanical properties of composites with different interfacial adhesion were measured, which further confirmed the effect of the grafting modification.     

A photometric flow measurements method for characterisation of HPLC pumps

Summary The measurement of flow constancy and pulsation amplitudes of HPLC pump based on the photoconversion of malachite green leucocyanide is described. The irradiation time and hence the degree of conversion of the leucocyanide is correlated to flow fluctuations of piston driven HPLC pumps. It is possible to measure the amplitude of pulsations and determine the constancy of the flow rate. Most of the pumps show a flow stability better than ±1% measured as relative standard deviation of the flow rate under HPLC conditions (pressure drop 100 bar at 1 ml/min flow rate). The most expensive pump of those tested showed less than ±0.5% flow instability, however, this result was achieved by installation of a large-volume pulsation damper. The method described also allows flow rate measurements under FIA conditions where there is little or no pressure drop at the pump outlet.     

Molecular Tailoring of Surfaces: Pulsed Plasma Polymerization of Bromine Containing Monomers

The use of a variable duty cycle pulsed RF plasma is shown to provide film chemistry control during polymerization of saturated (CH₂Br₂) and unsaturated (CH₂=CHCH₂Br) bromine containing monomers. With both monomers, the degree of bromine atom retention in the films is observed to increase in a progressive fashion as the RF duty cycle employed during plasma polymerization is decreased. The film deposition rates, when expressed in terms of thickness per Joule of RF energy input, increase rapidly as the RF duty cycles are reduced. Additionally, the film morphology is observed to become increasingly smooth with decreasing RF duty cycles during deposition, as illustrated with the allyl bromide monomer. The film chemistry controllability of this study is demonstrated with monomers possessing the relatively weak C-Br bond. As such, the present work represents an important extension of the pulsed plasma polymerization approach to include retention of a labile bond during film formation. The introduction of reactive surface functional groups, at controlled densities, provides additional molecular tailoring possibilities via subsequent chemical derivatization processes.     

In-situ investigations of the curing of a polyester resin

Quasi-isothermal curing of a polyester resin was studied at different catalyst concentrations and temperatures in-situ by ¹H-NMR relaxometry and NIR spectroscopy simultaneously. Sample and probe temperatures were also recorded. An autocatalytic kinetic model, optionally including a diffusion term, was successfully applied to describe and predict the curing kinetics of the polyester resin as a function of temperature and catalyst concentration, although the diffusion effect is relatively weak in the investigated system under the experimental conditions. The corresponding kinetic coefficients and the reaction activation energy were obtained by fitting the models to the data, assuming an Arrhenius relation.     

A Two‐Photon H2O2‐Activated CO Photoreleaser

Carbon monoxide (CO) is proposed as an active pharmaceutical agent with promising pharmaceutical prospects, as it has been involved in multifaceted modulation of diverse physiological and pathological processes. However, questions remain for therapeutic application of inhaled CO attributed to the inherent great affinity between CO and hemoglobin. Therefore, a robust platform with the function of CO transport and controllable release, depending on the local status of an organism, is of prominent significance for effectively avoiding the side effects of CO inhalation and optimizing the biological regulation function of CO. Utilizing the oxidative stress biomarker H₂O₂ as a trigger and combining with photo‐control, a two‐photon H₂O₂‐activated CO photoreleaser, FB, featuring highly sensitive and specific H₂O₂ sensing and photocontrollable CO release, was developed and the vasodilation effect of CO against angiotensin II was demonstrated.     

统计质量保证技术在分析测试实验室内部质量控制中的应用

对通过统计质量保证（SQA）技术进行分析测试实验室内部质量控制（IQC）的方法作了初探。研究结果表明,SQA技术的应用能保证实验室始终处于统计受控状态,确保测试数据的有效性,有利于分析测试实验室质量保证活动的开展。