试样研磨对铜合金主要元素分析结果的影响

本文从砂带，研磨方法，试样表现状况三个方面，分析了试样研磨对铜合金主要元素测试结果的影响。     

Kristallstrukturen der Fluorochloroplatinate(IV) cis-[(C5H5N)2CH2][PtF4Cl2], trans-[(C5H5N)2CH2][PtF4Cl2] · H2O und [(C5H5N)2CH2][PtF5Cl]

Crystal Structures of the Fluorochloroplatinates(IV) cis-[(C₅H₅N)₂CH₂][PtF₄Cl₂], trans-[(C₅H₅N)₂CH₂][PtF₄Cl₂] · H₂O, and [(C₅H₅N)₂CH₂][PtF₅Cl] The complex ions cis-[PtF₄Cl₂]^2?, trans-[PtF₄Cl₂]^2? and [PtF₅Cl]^2? have been synthesized by stereoselective ligand exchange reactions utilizing the trans effect and are separated by ion exchange chromatography on diethylaminoethyl cellulose. These anions form stable AB-type salts with the doubly charged cation dipyridiniomethane, [(C₅H₅N)₂CH₂]²⁺. X-ray structure determinations on single crystals of cis-[(C₅H₅N)₂CH₂][PtF₄Cl₂] ( 1 ) (monoclinic, space group P2₁/n with a = 10.379(10), b = 9.635(2), c = 13.738(2) Å, β = 99.142(10)°, Z = 4), trans-[(C₅H₅N)₂CH₂][PtF₄Cl₂] · H₂O ( 2 ) (triclinic, space group P1 with a = 7.757(4), b = 10.059(7), c = 10.408(6) Å, α = 82.49(5), β = 68.92(4), γ = 75.46(4)°, Z = 2) and [(C₅H₅N)₂CH₂][PtF₅Cl] ( 3 ) (orthorhombic, space group Pnma with a = 10.394(3), b = 13.320(2), c = 9.2694(10) Å, Z = 4), reveal the perfect ordering of the anion sublattice. The stronger trans influence of Cl compared with F is observed in asymmetric axes $ {\rm F}^ \bullet $? Pt? Cl′. The bond lengths Pt? $ {\rm F}^ \bullet $ are 0.026 Å (1.4%) longer and the Pt? Cl′ distances are 0.078 Å (3,3%) shorter in comparison with those of symmetrically coordinated axes. The weakening of the Pt? $ {\rm F}^ \bullet $ bond and the strengthening of the Pt? Cl′ bond is better recognizable from shifts of the stretching vibrations by 8% to lower and by 13% to higher frequencies, respectively. Correspondingly, the valence force constants are found to be 15% lower and 22% higher. The trans influence is observed most distinctly in the ¹⁹F-nmr spectra exhibiting the coupling constant ¹J($ {\rm F}^ \bullet $Pt) to be 29% smaller than ¹J(FPt).     

反应原料组成对单分散苯乙烯微球粒径及其分布的影响

采用分散聚合工艺制备微米级单分散聚苯乙烯微球，并对分散聚合反应的内部影响因素(分散稳定剂、助稳定剂、单体、引发剂)进行了研究．结果表明，随着分散稳定剂和助稳定剂用量的增加，聚苯乙烯微球的粒径减小；随着单体和引发剂用量的增加，聚苯乙烯微球的粒径增大．分散稳定剂和单体用量是影响聚苯乙烯微球粒径分布的两个主要内部因素．     

The theoretical basis of column chromatography in multicomponent separations. Part 2: Peak capacity. Column systems with good selectivity

The selectivity of a column system, S, defined by equation 28, includes a variation coefficient (β) of plate number with capacity ratio which has a large influence on the peak capacity, as shown in Fig. 18. Some typical chromatograms are given. In order to predict S for a column system from Kovat's Index, equations 40 and 41 are given to calculate the constant of the carbon number rule for squalane at different temperatures or for different stationary phases. The specific retention value of heptane on squalane at different temperatures can be calculated from equation 42. The nonpolarity index, defined by equation 43, was used to calculate the retention value of heptane on various stationary phases. In liquid chromatography, the order of elution may be reversed by changing the composition of the eluent on the same chemically bonded silica (manufactured in China). The linear relations between the log retention values of different kinds of solutes or of a single solute on the silicas of different surface areas when using the same eluent are given.     

Influence of some inorganic salts on the polarity of apolar polymer phases in capillary gas chromatography

Different stationary phases were prepared by mixing a series of inorganic salts with dimethylsiloxane polymer (SE-30) and then tested by capillary gas chromatography. It was demonstrated that the polarity (as evaluated by measurement of Rohrschneider constants) of the mixed stationary phases, which is inferior or equal to that of a medium-polar OV-25 phases, reached even lower values than SE-30 alone. The influence of NaF, NaCl, NaBr, AgNO₃, and other inorganic salts on the polarity of capillaries is reflected by a better resolution and shorter retention time of cis/trans isomers of fatty acid methyl esters (FAMES) as well as positional isomers of triglycerides.     

Stereoisomeric flavor compounds,part LVIII: The use of heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-β-cyclodextrin as a chiral stationary phase in flavor analysis

The characteristics of the new chiral stationary phase heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-β-cyclodextrin are outlined and compared with permethyl- and perethyl-β-cyclodextrins.     

Kristallstrukturen und Schwingungsspektren von Tetrahalogenoacetylacetonatoosmaten(IV), [OsX4(acac)]−, X  Cl,Br, I

Crystal Structures and Vibrational Spectra of Tetrahalogenoacetylacetonatoosmates(IV), [OsX₄(acac)]^?, X ? Cl, Br, I By reaction of the hexahalogenoosmates(IV) with acetylacetone the tetrahalogenoacetylacetonatoosmates(IV) [OsX₄(acac)]^? (X = Cl, Br, I) are formed, which have been purified by chromatography and precipitated from aqueous solution as tetraphenylphosphonium (Ph₄P) or cesium salts. X-ray structure determinations on single crystals have been performed of (Ph₄P)[OsCl₄(acac)] ( 1 ) (triclinic, space group P1 , a = 9.9661(6), b = 11.208(2), c = 13.4943(7) Å, α = 101.130(9), β = 91.948(6), γ = 96.348(8)°, Z = 2), (Ph₄P)[OsBr₄(acac)] ( 2 ) (monoclinic, space group P2₁/n, a = 9.0251(8), b = 12.423(2), c = 27.834(2) Å, β = 94.259(7)°, Z = 4) and (Ph₄P)[OsI₄(acac)] ( 3 ) (monoclinic, space group P2₁/c, a = 18.294(3), b = 10.664(2), c = 18.333(3) Å, β = 117.68(2)°, Z = 4). Due to the increasing trans influence in the series O < Cl < Br < I the Os? O^. distances of O^.? Cl? X′ axes are lengthened and the OsO^. stretching vibrations are shifted to lower frequencies. The Os? X′ bond lenghts are shorter as compared with symmetrically coordinated X? Os? X axes.     

微量元素La对Al—Si合金凝固过程的影响

本文用差热分析法系统地研究了La掺杂对Al-Si共晶合金、亚共晶、超共晶的动态凝固过程的影响。结果表明,La促使α(Al)成核,使体系中初晶α(Al)的析出温度比AJ-Si二元合金中Al初晶的实际析出温度明显提高;La对初晶Si的成核和长大起抑制作用,使超共晶中初晶Si相析出温度较二元合金中的Si初晶的实际析出温度明显降低。     

凝胶型苯乙烯系离子交换树脂的强度及抗渗透性的影响因素研究 (I)

本文就单体组成中不同引发剂，链转移剂，环二烯，烯丙基类化合物和氧气等对凝胶型苯乙烯系阳离子交换树脂的强度和抗渗透性的影响进行了系统研究。结果显示，采用0．30％的过氧化2－乙基己酸叔丁酯（OT）和0．01％的过氧化苯甲酸特丁酯（CP）代替过氧化二苯甲酰（BPO作引发剂，或者加入0．02％的链转移剂十二烷基硫醇，均能够在一定程度上改善共聚物珠粒的结构均匀性，提高其合成的离子交换树脂的磨后圆球率和抗渗透性能。     

Headspace-gas chromatography: The influence of sample volume on analytical results

Summary The role of the volume of the sample and the sample vial in equilibrium headspace-gas chromatography is discussed. A new term, thesample phase fraction (_S) is introduced. It is shown that if the value of _S is kept constant, the vial's volume has no influence on the sensitivity of the headspace analysis (which is proportional to the concentration of the analyte in the headspace). In a given headspace sampling system, concentration of the compound of interest in the headspace (c _G ^* ) at equilibrium is related to the value of _S: a higher _S will increase c _G ^* . However, the influence is important only in the case of low distribution coefficients: in the case of higher distribution coefficients this influence is negligible. This conclusion is also true for small changes in the sample volume in duplicate analyses: exact reproducibility of the sample volume is important only in the case of low distribution coefficient values.