Spectral regions selection to improve prediction ability of PLS models by changeable size moving window partial least squares and searching combination moving window partial least squares

Changeable size moving window partial least squares (CSMWPLS) and searching combination moving window partial least squares (SCMWPLS) are proposed to search for an optimized spectral interval and an optimized combination of spectral regions from informative regions obtained by a previously proposed spectral interval selection method, moving window partial least squares (MWPLSR) [Anal. Chem. 74 (2002) 3555]. The utilization of informative regions aims to construct better PLS models than those based on the whole spectral points. The purpose of CSMWPLS and SCMWPLS is to optimize the informative regions and their combination to further improve the prediction ability of the PLS models. The results of their application to an open-path (OP)/FT-IR spectra data set show that the proposed methods, especially SCMWPLS can find out an optimized combination, with which one can improve, often significantly, the performance of the corresponding PLS model, in terms of low prediction error, root mean square error of prediction (RMSEP) with the reasonable latent variable (LVs) number, comparing with the results obtained using whole spectra or direct combination of informative regions for a compound. Regions consisting of the combinations obtained can easily be explained by the existence of IR absorption bands in those spectral regions.     

Ab initio structure determination of new compound Ba3(BO3)(PO4)

The crystal structure of new compound Ba₃BPO₇ was determined by ab initio method from high-resolution conventional X-ray powder diffraction data. The Rietveld refinement converged to R_p=5.92%, R_wp=8.87%, R_exp=5.00% with the following details: Hexagonal, space group P6₃mc, a=5.4898 (1) Å, c=14.7551(1) Å, Z=2. The basic unit of the structure is the [BaO₁₀]-[BO₃]-[PO₄] polar polyhedra-chain composed of Ba1-B-P-O cluster. These chains, running along c-axis, stack in a HCP mode to build the whole structure with triangular prism channels. The channels are parallel to c-axis too, in which Ba2 and Ba3 are located.     

[Ni(dien)2]2[Mn(NCS)6]·H2O的合成、晶体结构

The crystal of [Ni(dien)₂]₂[Mn(NCS)₆]·H₂O was synthesized and the structure of its single crystal was determined by X-ray diffraction. The crystal is monoclinic system, space group P2₁/c with a=16.544(3),b=15.137(2), c=17.334(3)?, β=99.90(1)°, V=4276.3(12)?³, Z=4, D_c=1.479g·cm^-3, M_r=951.55, F(000)=1998, μ=1.489mm^-1, R=0.0399, R_w=0.0958. IR was also determined.     

K-Pb-Tl-O复合氧化物的合成和电子结构的XPS研究

用熔盐阳极电沉积法合成了导电的复合氧化物K-Pb-Tl-O晶体.这些晶体具有纳米尺寸层状结构.用XPS对其进行了表征,并与相关的化合物进行了比较.实验表明,氧化物中的Pb和Tl都以高价态的单一价态存在,但电子结合能比相应的非导电低价化合物的低.该文用原子外弛豫效应解释了复合氧化物中的Pb和Tl的结合能的反常现象.讨论了它们的价电子结构与导电性的关系.     

Determination of volatile components in peptic powder by gas chromatography-mass spectrometry and chemometric resolution

Gas chromatography-mass spectrometry (GC-MS) coupled with chemometric resolution upon two-dimensional data was proposed as a method for the analysis of volatile components in a traditional Chinese medicinal preparation peptic powder which contains Rhizoma Atractylodis, Pericarpium Citri Reticulatae, Cortex Magnoliae Officinalis and Radix Glycyrrhizae. Ninety-three components were separated and 65 of them were qualitatively and quantitatively analyzed which represented about 90.28% of the total content. With the help of chemometric resolution, the data were resolved into a pure chromatogram and a mass spectrum of each chemical component. The accuracy of qualitative and quantitative results was greatly improved by using the two-dimensional comprehensive information of chromatograms and mass spectra. The example showed that chemometric resolution could greatly enhance separation ability. This makes it possible to analyze complicated practical systems like traditional Chinese medicinal preparations with the help of coupled instruments and chemometric resolution methods.     

Syntheses and characterizations of three-dimensional channel-like polymeric lanthanide complexes constructed by 1,2,4,5-benzenetetracarboxylic acid

The hydrothermal reaction of YbCl(3) small middle dot6H(2)O with 1,2,4,5-benzenetetracarboxylic dianhydride resulted in [[Yb((b)btec)(1/4)((d)btec)(3/6)(H(2)O)(2)](4).6H(2)O](n)() (1) (H(4)btec = 1,2,4,5-benzenetetracarboxylic acid), and the solvothermal reaction of Er(NO(3))(3) small middle dot6H(2)O or TbCl(3).6H(2)O with 1,2,4,5-benzenetetracarboxylic dianhydride in H(2)O/acetic acid gave rise to [[Er(2)((c)btec)(2/4)((e)btec)(2/4)((f)btec)(2/4)(H(2)O)(4)].4H(2)O](n)() (2) and [[Tb(H(2)btec)(2/4)((f)btec)(3/6)(H(2)O)].2H(2)O](n)() (3), respectively. Complex 1 crystallizes in monoclinic space group C2/m with a = 20.8119(5) A, b = 17.6174(1) A, c = 5.7252(2) A, beta = 92.324(1) degrees, and Z = 1. 1 possesses a three-dimensional framework consisting of eight-coordinate ytterbium centers and two kinds of channels along the c axis. Complex 2 crystallizes in triclinic space group P with a = 9.6739(5) A, b = 11.0039(5) A, c = 11.5523 A, alpha = 104.8330(10) degrees, beta = 91.0000(10) degrees, gamma = 114.2570(10) degrees, and Z = 2. 2 has a three-dimensional framework comprising both eight- and nine-coordinate erbium centers and channels along the a axis. Complex 3 crystallizes in monoclinic space group P2(1)/n with a = 10.7246(12) A, b = 7.1693(9) A, c = 17.158(2) A, beta = 97.109(2) degrees, and Z = 4. 3 shows a three-dimensional framework containing nine-coordinate terbium centers and channels along the b axis. Uncoordinated water molecules occupy the channels in the three complexes. TGA and XRPD were determined for the three complexes, and the results illustrate that the framework of 1 is retained upon removal of uncoordinated and coordinated water molecules.     

新型高吸水聚合物凝胶型屏蔽暂堵剂MTC-1的合成及性能

以丙烯酸（AA）、丙烯酰胺（AM）、2-丙烯酰胺基-2-甲基丙磺酸（AMPS）为原料，蒙脱土（MMT）为改性剂，过硫酸钾和无水亚硫酸氢钠为氧化还原引发体系，六亚甲基四胺（C₆H₁₂N₄）为交联剂，采用水溶液聚合法合成了一种新型高吸水聚合物凝胶型屏蔽暂堵剂（MTC 1），其结构经IR表征。在最优合成条件（AM/AMPS/AA=11/7/1, m/m/m，引发剂加量0.6 wt%，于45 ℃反应2.5 h）下，MTC-1的最大吸水倍率为1006倍。岩心流动实验结果表明：MTC-1的堵水性能较高，封堵效率达到83.72%。     

金华地区饲料中铅、镉的检测

通过对金华地区多家饲料生产厂家所生产的饲料进行抽样调查,利用原子吸收分光光度计测定了饲料中铅、镉的含量。结果表明,所测饲料原料样品中,铅、镉的含量完全符合国家标准规定,合格率100%;铅、镉含量分别在0.005~0.157 mg/kg和0.06~0.104 mg/kg范围内,铅含量最高的是玉米为0.157 mg/kg,最低的是蚕豆为0.005 mg/kg;镉含量最高的是骨粉为0.104 mg/kg,最低的是豌豆和蚕豆为0.006 mg/kg。金华市饲料中铅、镉含量符合国家饲料卫生标准,可以安全喂养牲畜。     

配体交换毛细管区带电泳拆分未衍生化氨基酸

以铜（Ⅱ）-L-谷氨酸络合物为手性分离选择剂，对苯丙氨酸、酪氨酸和色氨酸3种非衍生芳香族氨基酸的手性对映体拆分进行了研究，建立了一种快速、简便拆分未衍生化的氨基酸对映体的配体交换毛细管电泳方法。在使用10mmol／L NH4AC（pH5．0），5mmol／L CuSO4和10mmol／L L-谷氨酸的条件下，成功地拆分了苯丙氨酸、酪氨酸手性对映体；色氨酸手性对映体也得到部分分离；考察了电泳缓冲液组成、pH值等影响分离效果的因素。     

A hybrid nonaqueous electrochemical supercapacitor using nano-sized iron oxyhydroxide and activated carbon

A beta-iron oxyhydroxide (FeOOH) was synthesized via a hydrolyzing route and investigated as a lithium intercalation host. It delivers a capacity of about 170 mAh/g and exhibits good cycling performance when charged/discharged in the voltage range from 1.6 V to 3.3 V. For the first time we have confirmed that FeOOH is suitable for using it as a negative electrode for hybrid electrochemical supercapacitor assembled with an activated carbon positive electrode in 1.0 M LiPF₆ ethylene carbonate/dimethyl carbonate (EC/DMC, 1:2 in volume) solution. The cell reveals a slightly sloping voltage profile from 0 V to 2.8 V and gives an estimated specific energy of 45 Wh/kg based on the total weight of two electrode materials, approximately two times of carbon/carbon electrochemical double layer capacitors. The hybrid supercapacitor shows a good cycling performance, it remains approximately 96% of initial capacity after 800 cycles at a charge/discharge rate of 4 C. The capacitor also shows a desirable rate capability, even at 10 C discharge rate, it holds 80% of capacity compared with that at 1 C discharge rate.