Selection of the Temperature in the Sugar Content Determination of Kiwi Fruit

In the last few years, the production of kiwifruit (Actinidia deliciosa) has undergone a significant development with increasing international market. Therefore, the use of fast and non-destructive methods for ripening control is desirable. In this sense, NIRS technology (Near Infrared Spectroscopy) has proved to be very useful. The objectives of this work were to estimate the soluble solids content from NIRS technology and to evaluate the influence of the kiwifruit temperature on the NIR measures. A sample of 210 fruits was collected and stored for three months under cold conditions. The NIR measures were done at three kiwifruit temperatures (0.5°C, 10°C and 20°C) and the refractometric index was determined at the end of the experiment. The reflectance spectra in the near-infrared region between 800 and 2500 nm were measured with a Varian CARY 500 spectrophotometer equipped with an integrated sphere to measure reflectance in solid samples. The information has been analysed with Unscramble and SPSS statistical programs, which include a wide range of rapid data-processing applications and procedures, with a large number of options and graphic representations. The test performed for this study are PLS (partial least squares regression) and DA (discriminate analysis). Results showed: the validity of this technology to obtain a relationship between the NIRS and the soluble solids content, and differences on the wavelengths used in the calibrations, depending on the kiwifruit temperature.     

Donor-Acceptor Complexes in Copolymerization. XVI. NMR Analyses of Alternating and Random Copolymers of Styrene and α-Methylstyrene with Acrylonitrile and Methacrylonitrile

An NMR investigation was carried out on random and alternating copolymers of acrylonitrile (AN) with a-methylstyrene (MS) and methacrylonitrile (MAN) with α-methylstyrene and styrene (S). The alternating MS-AN copolymer, prepared by complexation with AlEti_1-5Cl_1-5, was found to have a predominantly coisotactic configuration which was attributed to the interaction between the CH₃ and CN groups. The cotacticity of the alternating copolymer was found to be independent of the temperature of polymerization and the amount of AlEt_1-5Cl_1-5 used for complexation. The NMR spectra of random MS-AN copolymers of varying compositions indicated a high value (0.85) for the coisotacticity probability parameter (σ). The equimolar random MS-AN copolymer was also found to have essentially alternating sequences which was attributed to their low reactivity ratios. The equimolar alternating MS-MAN copolymer was found to have a random stereochemical configuration in which the coisotactic placement was slightly preferrred over the cosyndiotactic placement. The NMR spectrum of the equimolar free radical initiated MS-MAN copolymer lacked the fine structure observed in the spectrum of the alternating copolymer which was attributed to the presence of other sequences. The equimolar alternating S-MAN copolymer was found to have a high coisotactic configuration similar to that observed in the MS-AN copolymer. The equimolar free radical initiated S-MAN copolymer had a random sequence distribution.     

A soluble polyethyleneglycol-anchored phosphine as a highly active, reusable ligand for Pd-catalyzed couplings of aryl chlorides: comparison with cross and non-cross-linked polystyrene and silica supports

The so-called SPhos phosphine, an extremely active ligand in the amination and Suzuki coupling of sterically-hindered aryl chlorides, has been anchored on different supports such as non-soluble (cross-linked polystyrene) and soluble (non-cross-linked polystyrene and polyethyleneglycol) polymers, as well as high surface silica. SPhos anchored on polyethyleneglycol (PEG-SPhos) showed the best activity for both amination and Suzuki couplings. The PEG-SPhos ligand can be quantitatively recovered from the reaction mixture through precipitation with diethyl ether and recycled in four consecutive runs without loosing activity. ³¹P NMR spectra of the reused anchored ligand showed that deactivation of the PEG-SPhos ligand comes from the progressive oxidation of the phosphine-to-phosphine oxide.     

Study of depolymerization of cotton cellulose by Pb/PbO2 anode electrochemical catalysis in sulfuric acid solution

A novel method of cotton cellulose depolymerization is investigated in this paper. In this work, a three-electrode system, which contains a Pb/PbO₂ anode, two copper cathodes and a reference saturated calomel electrode (SCE), is applied to electrocatalytic depolymerization of cotton cellulose. After electrocatalytic depolymerization of cotton cellulose in 0.5M sulfuric acid solution using Pb/PbO₂ anode at room temperature (25 °C), the average degree of polymerization (DP) can be reduced to the minimum 367 from 1100. The effects of operating parameters, such as supporting electrolyte, current density and reaction time are investigated as well. The composition of the products in filtrate is characterized by phenol-sulfuric acid method, extraction, NMR, GC-MS and High Performance Liquid Chromatography (HPLC). In addition, the solid sample is analyzed via SEM images, XRD diffractogram, Ubbelohde capillary viscometer and FT-IR spectra. The results suggest that it is effective to convert cotton cellulose to soluble sugar, 5-hydroxymethylfurfural (5-HMF) and other products by electrocatalytic methods. However, the yield of products is low and needs further study. A novel method to significantly convert cotton cellulose to biofuels and biomaterials can be hopefully developed if the selectivity of cotton cellulose electrocatalytic depolymerization is improved in the future.     

S、Cr共掺杂TiO2纳米材料的固相合成及其可见光降解性能

采用固相反应法分别合成了铬掺杂二氧化钛(Cr-TiO2)及硫和铬共掺杂二氧化钛(S-Cr-TiO2)纳米材料.并用XRD、SEM、UV-Vis、XPS、N2吸附等技术对材料进行了物相结构表征,同时研究了材料对水溶苯胺蓝的可见光降解性能.结果表明,在S-Cr-TiO2纳米材料中,硫以阳离子S6+进入二氧化钛晶格或晶格间隙...     

A Generalised character theory for modules

Crawley-Boevey's concept of a character (a notion derived from Schofield's Sylvester rank functions) is extended so that characters with different image sets and classes may be analysed. A method of passing from these generalised characters to theories of modules is given and a converse technique is seen to be possible in certain cases. We consider in depth what happens when the character image is taken to be the ordinals with addition taken to be the Cantor sum. In particular we define a process whereby any Σ-pure-injective module satisfying a reasonable criterion can be assigned a unique ordinal character.     

Schunck Classes of Soluble Leibniz Algebras

I set out the theory of Schunck classes and projectors for soluble Leibniz algebras, parallel to that for Lie algebras. Primitive Leibniz algebras come in pairs, one (Lie) symmetric, the other antisymmetric. A Schunck formation containing one member of a pair also contains the other. If ? is a Schunck formation and H is an ?-projector of the Leibniz algebra L, then H is intravariant in L. An example is given to show that the assumption that the Schunck class ? is a formation cannot be omitted.     

On Semi-Cover-Avoiding Maximal Subgroups and Solvability of Finite Groups

A subgroup H of a finite group G is said to be “semi-cover-avoiding in G” if there is a chief series of G such that H covers or avoids every chief factor of the chief series. In this article, some new characterizations for finite solvable groups are obtained based on the assumption that some subgroups have semi-cover-avoiding properties in the groups.     

Finite Soluble Group Generated by the Conjugacy Class of an Involution

Let G be a finite group and P a subgroup of order 2. We study in this article the structures of the soluble subgroup of G that is generated by three conjugates of P. We use the results we proved about the soluble subgroups that are generated by three conjugates of P to find a soluble analogue of the Baer–Suzuki Theorem in the case prime 2.     

烤烟的近红外光谱检测模型

对杀青烟叶蛋白质和水溶性总糖含量的光谱检测,发现近红外光谱（1100-2500nm）的检测模型优于可见-近红外光谱（350-2526nm）,烟粉检测模型优于片状烟叶的检测模型.通过对烟叶全部光谱数据不同的预处理来探究其蛋白质和水溶性总糖的近红外光谱的检测模型,并利用近红外有效波长对施木克值的含量进行预测.利用偏最小二乘法（PLS）通过训练集的交叉验证建立回归模型,结果表明：（1）对原始光谱进行二阶导数变换后,得到蛋白质含量预测模型的预测集r=0.9768、RMSE=0.6843;（2）对原始光谱每隔51个点进行移动平滑处理及主成分数为8时,水溶性总糖含量预测模型的预测集r=0.9495、RMSE=0.9049;（3）基于82个波长对施木克值的预测模型的预测集r=0.9356、RMSE=0.1060.