基于支持向量机的羰基化合物红外光谱研究

设计了一个4层分等级分类系统，通过支持向量机技术对羰基化合物的红外光谱成功地进行了信息分类和提取，并与人工神经网络进行比较，结果表明：支持向量机对羰基类化合物红外光谱分类效果优于人工神经网络；另外详细探讨了表征酰胺类化合物的特征光谱峰片段对识圳伯仲叔酰胺的影响，证明了酰胺的N-H伸缩振动峰对识别伯仲叔酰胺贡献最大，为构建红外光谱智能解析系统提供了定量依据。     

电解沉积压电频移分析的理论与验证

提出了控制电位电解和恒电流电解两类电解沉积的压电频移分析法测定的理论公式,用实验结果验证了它的正确性.     

Construction and analytical application of ion-selective piezoelectric sensor for atropine sulfate

The method describes the use of a piezoelectric quartz crystal (PQC) as a substitute for ion-selective electrodes. The approach is feasible when the membrane materials are electrically non-conductive and membrane potential measurements are consequently not possible. An ion-selective piezoelectric sensor sensitive to atropine sulfate was constructed by coating a PVC membrane containing activant on one the side of a PQC. On the basis of selective adsorption of atropine ions across the modified film and the sensitive mass response of PQC, the method exhibits a sensitive, rapid response and is easy to operate without pretreatment of the sample. The logarithm of the frequency shift gave a linear relationship with the logarithm of atropine sulfate concentration in the 1.0 x 10(-8)-1.0 x 10(-3) M range with a detection limit of 5.0 x 10(-9) M at pH 7.0. Recoveries were from 98.7-102.2%. Two activants, atropine tetraphenylborate and atropine dipicrylaminate, were synthesized and investigated. Influencing factors were also examined and optimized. The results for real samples obtained by the proposed method agreed with those obtained by conventional methods.     

反相高效液相色谱二极管阵列检测器对戊四硝酯粉质量的研究

建立了戊四硝酯粉含量及有关物质的RP-HPLC测定法。采用ODS色谱柱,甲醇/水(70∶30)为流动相,使戊四硝酯与有关物质基线分离,二极管阵列检测器检测波长206nm。本方法操作简便,重现性好。     

Preparation and characterization of a novel pH-sensitive ion exchange resin

Methylacrylic acid/styrene cross-linked with divinylbenzene is a novel pH-sensitive ion exchange resin. Microspheres of this resin were characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The microspheres showed a pulsatile swelling behavior when the pH of the media changed. The pH-sensitive microspheres were loaded with salbutamol sulfate and the drug-release characteristics were studied under both simulated gastric and intestinal pH conditions. The results obtained showed that the drug release also depended on the pH of the release media.     

Triboelectric pulsed direct current for self-powered sterilization of cellulose fiber

A variety of liquid energy exists in papermaking engineering and has not yet been developed and utilized. In addition, for the papermaking industry, the presence of slime can seriously affect the quality of the finished paper and can lead to paper breaking. The current slime control strategies cannot completely solve the problem and also have some low toxicity. In this study, a method of self-powered sterilization of cellulose fibers by using triboelectric pulsed direct current is reported. A liquid–solid triboelectric nanogenerator (L–S TENG) was used to convert the liquid energy of nanocellulose suspension into electrical energy and convert this electrical energy into pulsed direct current for self-powered sterilization of cellulose fiber. A hydrophobic coating material is used as solid triboelectric material and electrode for sterilization. Driven by L–S TENG, the electrodes exhibited an excellent sterilization rate against four microorganisms including Escherichia coli, Aspergillus niger, Candida albicans, and Klebsiella pneumoniae, which from slime in the papermaking industry. This study could provide a basic research theory for liquid energy harvesting in the papermaking industry, and also provide a new strategy for pulp sterilization.

Graphical abstract

     

穴状Schiff碱配合物［Gd(NO3)·L］(NO3)2的晶体结构

A new mononuclear gadolinium complex ［Gd(NO₃)·L］(NO₃)₂ of Schiff base cryptand was obtained by condensation of tris (2-aminoethyl)amine with 2,6-diformyl phenol in template procedure. The complex was characterized by elemental analysis, IR, and x-ray single crystal diffraction analysis. Gadolinium is nine-coordinate in trigonal tricapped prism with five oxygen atoms from three phenols and a bidentate nitrate group, and four nitrogen atoms from three imino C=N bonds and a tertiary amine in the cryptand. The complex crystallized in triclinic system space group P1, a=1.0839(2) nm, b=1.2600(4) nm, c=1.7595(4) nm, α=82.09(2)°, β=89.22(2)°, γ=84.06(2)°， V=2.367(2) nm³, Z=2.     

Microdetermination of sulfite with a piezoelectric crystal detector

A piezoelectric method is proposed for the determination of sulfite in concentration range 1 × 10^–7–1 × 10^–5 mol/1. The method is based on the redox reaction of sulfite with iodine followed by measuring frequency change of the piezoelectric crystal caused by the unreacted iodine. The method is applied to the determination of sulfite in liquor.     

De novo sequencing of tryptic peptides sulfonated by 4-sulfophenyl isothiocyanate for unambiguous protein identification using post-source decay matrix-assisted laser desorption/ionization mass spectrometry

A simple method of solid-phase derivatization and sequencing of tryptic peptides has been developed for rapid and unambiguous identification of spots on two-dimensional gels using post-source decay (PSD) matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The proteolytic digests of proteins are chemically modified by 4-sulfophenyl isothiocyanate. The derivatization reaction introduces a negative sulfonic acid group at the N-terminus of a peptide, which can increase the efficiency of PSD fragmentation and enable the selective detection of only a single series of fragment ions (y-ions). This chemically assisted method avoids the limitation of high background normally observed in MALDI-PSD spectra, and makes the spectra easier to interpret and facilitates de novo sequencing of internal fragment. The modification reaction is conducted in C(18) microZipTips to decrease the background and to enhance the signal/noise. Derivatization procedures were optimized for MALDI-PSD to increase the structural information and to obtain a complete peptide sequence even in critical cases. The MALDI-PSD mass spectra of two model peptides and their sulfonated derivatives are compared. For some proteins unambiguous identification could be achieved by MALDI-PSD sequencing of derivatized peptides obtained from in-gel digests of phosphorylase B and proteins of hepatic satellite cells (HSC).     

Microfluidics: from dynamic lattices to periodic arrays of polymer disks

We used coupling of flow and geometric confinement to assemble emulsion droplets in two-dimensional gliding lattices with a high degree of order and symmetry. Highly monodisperse discoid droplets with circular shapes were generated in a microfluidic flow-focusing device. Originally, close-packed lattices formed from these circular discoid droplets. Progressive confinement led to the gradual deformation of the circular disks: first, they elongated in the direction parallel to the direction of flow and then transformed into hexagons. Assembly driven by the combination of flow and confinement also allowed for the formation of lattices from droplets with a bimodal size distribution. We used photopolymerization of the monomer droplets to trap the lattice structure in the solid state and produce highly periodic arrays of solid polymer disks.