EIGHT-POINT STRAIGHT-LINE-NET-DIAGRAMS OF BINARY SIX-PHASE (n+4) MULTISYSTEMS (Ⅱ)——DERIVATION FROM THEORY OF PHYSICALLY REAL NETS

Based on the theory of physically real nets, the 8- point straight-line nets of bi-nary 6- phase (n + 4) multisystems (31 in toto) have been derived directly from the l-point straight-line nets. This result is in complete agreement with that derived fromthe theory of closed nets, indicating the incorrectness of the previous conclusion thatthere is only one 8-point straight-line net which corresponds to only one 8- pointstraight-line-net-diagram for binary 6- phase multisystems.     

APPLICATION OF COMBINATION PRINCIPLE FOR CLOSED NETS IN n k(k≥4) PHASE MULTISYSTEMS——ESTABLISHMENT OF COMPLETE SYSTEMS OF CLOSED NETS FOR UNARY SIX-PHASE (n 5) MULTISYSTEMS

Applying the combination principle for closed nets in n k(k≥4) phase multisystems, the author has derived the complete systems of closed nets of unary six-phase(n 5) multisystems. Every typical closed net involves exclusively eight invariant points. Two topologically distinct configurations of the typical closed nets have been generated from two different ways of combination, and hence, two distinct representation polyhedra have been constructed. On the basis of these configurations or polyhedra, the author has rederived all the 16 basic forms of phase diagrams given by Kujawa et al.     

COMBINATION PRINCIPLE FOR CLOSED NETS OF n k(k≥4) PHASE MULTISY

In this paper some properties of n k (k≥4) phase multisystems are discussed and thesymbolism depicting them is proposed systematically. Upon this, the combination principle forclosed nets of n k phase multisystems is preseted and elucidated. The combination principlestates: Any closed net of one n k (k≥4) phase multisystem must be a combination of two ormore distinct n 3 order submultisystem closed nets belonging to the given n k multisystem,if it is not one of the n 3 order submultisystem closed net itself. The presentation of thecombination principle provides both the theoretical basis and the practical way for investigationand solution of the topological configurations of the phase diagrams of any n k phase multisystems.     

Computer plotting of multisystem p-T, T-X, p-X phase diagrams

As a continuation to the work reported by Yin in 1992, a new procedure is presented for computer plotting of the stable equilibrium phase diagram of an n-component system composed of (n + k) stoichiometric phases (or fluid species) where 2≤k≤4. The main points of the procedure are: (i) using the technique of sequential-absence of phases (SAP) to determine the possible invariant and univariant assemblages in a given multisystem; (ii) using the matrix inverse technique to generate and balance the univariant reactions from the corresponding univariant assemblages; (iii) comparing the phase assemblage at each invariant point with that of each univariant reaction to select the univariant curves about the corresponding invariant point; (iv) locating the invariant points with the technique of finding common equilibrium relation (CER); (v) using the sign function matrix (SFM) technique to discriminate between the stable portion of a univariant curve and its metastable extension about the corresponding invaria     

NETS IN MULTISYSTEMS OF n 3 AND n 4 PHASES

From the free energy surfaces in G-p-T space a series of basic characteristics have beensummarized. For the reactions of most systems with phases of constant composition, eachof the surfaces should be approximate to a plane. After they meet, the points, curves andsurfaces possess distinct stability levels. Across the intersecting curves and points, the freeenergy surfaces and curves will change their stability levels. Linking invariant points ofdistinct stability levels, we can get various univariant curves differing in structure. Theangular extent between two univariant curves around the invariant points is less than 180°.The surfaces meeting in space and projecting onto the p-T section will give rise to partiallyclosed or open, rather than completely closed nets. Finally, based upon the basic characteristicsand criteria, we have derived the partially closed nets of n 3 and n 4 phases with maxi-mum closure by using geometrical and analytical methods. From the free energy surfaces in G-p-T space a series of basic characteristics have beensummarized. For the reactions of most systems with phases of constant composition, eachof the surfaces should be approximate to a plane. After they meet, the points, curves andsurfaces possess distinct stability levels. Across the intersecting curves and points, the freeenergy surfaces and curves will change their stability levels. Linking invariant points ofdistinct stability levels, we can get various univariant curves differing in structure. Theangular extent between two univariant curves around the invariant points is less than 180°.The surfaces meeting in space and projecting onto the p-T section will give rise to partiallyclosed or open, rather than completely closed nets. Finally, based upon the basic characteristicsand criteria, we have derived the partially closed nets of n 3 and n 4 phases with maxi-mum closure by using geometrical and analytical methods.     

A simple, universal theory and method for computer plotting of stable equilibrium phase diagrams of a multisystem——SFM method

A new easy method has been presented to calculate the variable intervals corresponding to the stable univariant curves and to discriminate the stabilities of invariant points. This method and the one reported previously constitute a simple and universal theory for the computer-plotting of the equilibrium phase diagrams of a multisystem——sign function matrix (SFM) discrimination method. Its main steps are: determining the stable univariant scheme according to the derivative (or difference) of △rGm; grouping the univariant curves by comparisons of the mutual relations among them; determining the existing intervals of the variables for the stable curves by comparisons of coordinate values of the curves about the invariant point; determining the stabilities of invariant points by comparisons of relations between the common curves and the invariant points. This method is suitable for any kind of phase diagram of closed or open systems in a phase diagram "space" with either 2 or more than 2 dimensions.     

SOME PROPERTIES OF CLOSED-NET-DIAGRAMS OF n k(k≥3) PHASE MULTISYSTEMS

In this paper, some properties of closed-net-diagrams (CND's) of n 3 and n 4 phasemultisystems are discussed, and the theorem on the so-called Divariant Assemblage Charac-teristic Stability Polygons is proposed. The theorem states: Any divariant assemblage ofn k(k≥3) phase multisystems can be stable in a k-polygon possessing no diagonals inappropriate closed-net-diagrams at most, and in a triangle at least. Following the proof ofthis theorem, the authors specially emphasize that this theorem does not mean that there mustexist k-polygons possessing no diagonals in each closed-net-diagram or realistic phase diagramof n k phase multisystems, even though the realistic phase diagram has the maximum closure.     

CONSTRUCTION OF EQUILIBRIUM P-T BUNDLES OF COMBINATION OF n+2 PHASES ON PETROGENETIC GRIDS

This paper first discusses the algorithm for balancing reactions of the combination of n + 2 phases around an invariant point on a P-Tdiagram, and then emphatically develops a new algorithm for the arrangement of univariant reaction lines, using a signum matrix V·F or S·F, where V and S are diagonal matrixes of signum of △V and △S in n+2 univariant reactions respectively, and F is a signum matrix of stoichiometric coefficients of phases in reactions. Using this new algorithm greatly simplifies relative computer programs, brings out the automatic construction of equilibrium P-T curves of combination of n +2 phases, and further makes it possible to construct a whole petrogenetic grid automatically     

EIGHT-POINT STRAIGHT-LINE-NET-DIAGRAMS OF BINARY SIX-PHASE (n+4) MULTISYSTEMS (Ⅰ)——DERIVATION FROM NINE-POINT CLOSED-NET-DIAGRAMS

The 9-point closed-net-diagrams of binary 6-phase multisystems contain 2 basic types ofnon-straight-line portions. Only the removal of an invariant point which is shared by all thenon-straight-line portions in a 9-point closed-net-diagram can generate an 8-point straight-line-net-diagram. All together 67 distinct 8-point straight-line-net-diagrams have been derived forbinary 6-phase multisystems. They correspondingly belong to 31 distinct 8-point straight-line-nets (namely, 31 distinct 8-point sets), showing that the previous conclusion that there existsonly one 8-point straight-line-net-diagram for binary 6-phase multisystems is incorrect.     

THE STABILITY OF LAIHUNITE——A THERMODYNAMIC RE-ANALYSIS

A topological analysis on the ternary 7-phase multisystem involving laihunite (FeO-Fe_2O_3-SiO_2; Q-H-M-W-L-Fa-fs) in P-T plane has resulted in an n+4 phase closed-net-diagram. The most possible straightline-net-diagram was derived by using the thermodynamic properties of the phases concerned. From the straight-line-net-diagram it is apparent that laihunite is not a phase stable only at high pressures. P-T-fo_2, analysis suggests that the formation and stabilization of laihunite are closely related to oxygen fugacity. However, laihunite shows different ways of formation at different pressures. At low pressures, it is formed via the oxidation of fayalite; with increasing pressures the contribution of ferrosilite to the formation of laihunite increases; at very high pressures laihunite can be formed only by the oxidation of ferrosilite.     

Subsolidus binary phase diagram of the bilayer compounds [n-C_nH_(2n+1)N(CH_3)_3]_2ZnCl_4(n = 16, 18)

The bilayer compounds[n-CnH2n+1N(CH3)3]2Zn Cl4(n=16,18)experience solid-solid phase transition within the temperature range of 310 to 340 K.The low-temperature crystal structures of the pure compounds are characteristic of the piling effect in which a 2D macro-anion Zn Cl42- is sandwiched between two alkylammonium layers.These layers become conformationally disordered in the high-temperature phases.The structures can alternatively be viewed as a double layer of alkylammonium ions between Zn Cl42- sheets and can be considered as crystalline models of lipid bilayers.The experimental subsolidus binary phase diagram of[n-C16H33N(CH3)3]2Zn Cl4-[n-C18H37N(CH3)3]2Zn Cl4 has also been established over the whole composition range by differential scanning calorimetry(DSC)and X-ray diffraction.In the phase diagram,one intermediate compound[n-C16H33N(CH3)3][n-C18H37N(CH3)3]Zn Cl4 at WC16C3Zn%47.50 and two eutectoid invariants points at WC16C3Zn%35.10 and75.70 were observed;the respective temperatures of the two eutectoids are 320±1 and 315±1 K.In addition,there are three noticeable solid solution ranges in the phase diagram:α-phase at the left,β-phase at the right,andγ-phase in the middle.     

RULE OF DISTRIBUTION OF PHASE POINTS OF POLY-UNIT MOLECULES AND HOMOLOGOUS LINEAR LAW

The chain M-(A)_n-N or ring obtained by bonding n number of A's with the same chemical structure in the same way is called the poly-unit molecule. Jiang Mingqian has discovered the famous homologous linear law for the poly-unit chain. Xu Guangxian and Li Lemin have studied its quantum-chemical basis and put forward the new linear factor.In order to study further the basic quantum chemistry of the homologous linear law, it is necessary to have first a thorough knowledge of the orbital characteristics of the polyunit molecules. The author studied the orbitals and the energy levels of poly-unit molecules by using difference equations. Based on the past work the concept of phase points of orbital was established, and the rule of distribution of phase points was developed as well. It is found that the phase points of similar orbitals in the molecules of a homologous series appear to condense around a certain point. Based on this fact a theoretical proof of the homologous linear law was made.     

APPLICATION OF THEOREM OF CORRESPONDING RELATION TO P-T-x_i MULTICOMPONENT PHASE DIAGRAMS

By applying the theorem of corresponding relation to P-T-x_i multicomponent phase diagrams, six corollaries are obtained. These corollaries show the regularities and variation ranges of the total number of different phases in two neighboring phase regions (abbreviated to NPRs), the number of common phases existing in both NPRs, △Φ, the dimensions of phase boundaries between NPRs, R_1~', and the relation between them. The relation between the dimension of boundaries, R_1, and R_1 is also discussed. According to the above theorem and corollaries, the relation between NPRs and their boundaries in binary and ternary P-T-x_i phase diagrams is briefly analysed.     

磷酸钛离子交换薄层色谱分离无机离子(英文)

The chromatographic behavior of 30 inorganic cations has been studied on thin layers of titanium phosphate ion-exchanger using several aqueous,organic and mixed mobile phases.The separation of one ion from several other ions and also ternary and binary separations have been developed.Some important analytical separations are reported.The effect of pH of the mobile phase on retention factor(Rf)values of the cations in the presence of complex-forming anion along with the separation power of the ion-exchanger were studied.This ion-exchanger exhibits high sorption capacity and varying selectivity towards metal ions and makes it a suitable stationary phase in thin layer chromatography.     

Stabilizing the black phase of cesium lead halide inorganic perovskite for efficient solar cells

Inorganic perovskite cesium lead halide is extensively studied because of its potential in improving the thermal stability of perovskite materials. However, the tolerance factor of this type of perovskite is near the critical value, which leads to phase instability. The optoelectronic active black phases(α, β, and γ phases of CsPbI_3) are metastable at room temperature, which can be easily transferred into an optoelectronic inactive yellow phase(δ-CsPbI_3). This review highlights recent progress in stabilizing the black phase for efficient and stable perovskite solar cells.     

Phase Behavior of Liquid Crystals Formed in [C12mim]CI/H2O and [C12mim] Cl/Alcohols Systems

Phase behaviors of different binary systems involving 1-dodecyl-3-methylimidazolium chlo- ride （[C12mim]Cl） and H20, [C12mim]Cl and different alcohols （1-butanol, 1-pentanol, 1- hexanol and 1-octanol） are investigated at 25 ℃. Hexagonal liquid crystal phase （H1） is identified in [C12mim]Cl/H2O system, and lamellar liquid-crystalline （Lα） phase is found in [C12mim]Cl/alcohols systems by using polarized optical microscopy and small-angle X-ray scattering techniques. The formation of such phases is considered as a synergetic result of the solvatophobic force and the hydrogen-bonded network comprising an imidazoliuin ring, chloride ion and water （or alcohols）, which can be confirmed by Fourier transform infrared spectra. It is noticeable that in [C12mim]Cl/1-octanol system, the lattice spacings of lamellar phase increase with increasing C12mimCl concentration, which is opposite to the results of [C12mim]Cl/H2O system. This may result mainly from stronger static repulsion among hydrophilic headgroups of imidazolium salts arranged in the bilayers of lamellar structures. Further measurements by differential scanning calorimetry indicate that the lamellar phase is stable within a wide temperature range above room temperature. However, the lattice spacings decrease with the increase of temperature, which may. be due to the softening of the hydrocarbon chain of [C12mim]Cl molecules. In different alcohols systems, it is found that the lamellar lyotropic liquid crystal structure is easier to be formed when the carbon chain length becomes longer.     

PHASE STRUCTURES AND TRANSITION BEHAVIORS OF A TRIPHENYLENE DISCOTIC LIQUID CRYSTAL

The phase behaviors and structures of a triphenylene-derived discotic liquid crystal (LC) hexa-n-octoxyl-triphenylene (C8HET) were studied using the combined techniques of differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD), selected area electron diffraction (SAED) and polarized light microscopy (PLM). Onedimensional (1D) powder WAXD results at different temperatures coupled with DSC and PLM observations revealed that the C8HET compound possessed an LC phase and three different crystalline (K3, K2 and K1) phases below the isotropic (Ⅰ)melt. The I (←→) LC phase transition was thermodynamically reversible and independent of the heating and cooling rates. The development and experimental observation of the three crystalline phases relied on different thermal histories. Among the three crystalline phases in C8HET, the K3 phase is the most stable phase, while the K2 and K1 phases are metastable. Note that the K1 phase only formed via a quenching process. On the basis of structure sensitive diffraction experiments such as 2D WAXD of oriented samples and SAED of single crystals, detailed structures and molecular packings of these four ordered phases were identified. The LC phase exhibited a hexagonal columnar phase with 2D lattice dimensions of a = b = 2.38 nm and γ= 120°. All the three crystalline phases possess monoclinic unit cells, yet the γ angle is not 90° in the cases of the K2 and the K3 phases, while in the case of the K1 phase the α angle is not 90°.     

Investigation of scale inhibition mechanisms based on the effect of scale inhibitor on calcium carbonate crystal forms

To probe the scale inhibition mechanisms,calcium carbonate scale occurring before and after the ad- dition of scale inhibitors was collected.The results from scale SEM confirm that,without scale inhibitor, calcium carbonate scale shows rhombohedron and hexagon,which are the characteristic feathers of calcite.After addition of inhibitors,morphology of scale is changed,and the more efficient the scale inhibitor is,the more greatly the morphology is modified.To elucidate the scale constitute,they were further analyzed by FT-IR,XRD.Besides calcite,vaterite and aragonite occur in calcium carbonate scale after addition of inhibitors,and the higher scale inhibition efficiency is,the more vaterite presents in scale.It can be concluded that the alteration of morphology is ascribed to the change of crystal form. There are three stages in the crystallizing process including occurrence and disappearing of unstable phase,occurrence and disappearing of metastable phase,development of stable phase.Without scale inhibitors,metastable phases usually transform into stable phase,thus the main constitute of formed scale is calcite.When scale inhibitors are added,both formation and transformation of metastable phases are inhibited,which results in the occurrence of aragonite and vaterite.From the fact that more vaterite presents in scale with a more efficient scale inhibitor added,we can see that the function of scale inhibitor is realized mainly by controlling the crystallizing process at the second stage.     

甘油单油酸脂/水立方液晶体系流变性质的研究

Monoglyceride (MO) can form various liquid crystalline phases spontaneously in the presence of various amount of water at room temperature. The appropriate compositions from binary phase diagram of MO/H2O were selected to form cubic phases. The selected systems were studied at different salt concentrations and pH value using rheological methods. There was a weak effect of salt on viscoelastic properties of cubic phases formed from MO/H2O system. Hexagonal phase was formed when pH value was decreased or increased. The viscoelasticity of cubic phases was different from that of hexagonal liquid crystals. Rheological properties of MO/H2O cubic phases were stable at pH and salt concentration similar to physiological condition.     

Influence of Aging Time on the Properties of Precursors of CuO／ZnO Catalysts for Methanol Synthesis

The aging process of pure copper precursors and copper-zinc binary precursors were studied by XRD, TG-DTG and TPR techniques. The catalytic activity and stability of CuO/ZnO were tested using fixed-bed flow reactor, and the physical properties of the catalysts and Cu species were characterized with N2 adsorption and N2O passivation method, respectively. For the Cu-Zn binary system prepared at the precipitating condition of pH=8.0 and temperature=80℃, the initial phase was a mixture of copper nitrate hydroxide Cu2(NO3)(OH)3, georgeite and hydrozincite Zn5(CO3)2(OH)6. By increasing the duration of its aging time, the phase of Cu2(NO3)(OH)2 first transited to georgeite, and then interdiffused into Zns(CO3)2(OH)6 and resulted in two new phases: rosasite (Cu,Zn)2CO3(OH)2 and aurichalcite (Zn,Cu)5(CO3)2(OH)6. The former phase was much easier to be formed than the latter one, while the latter phase was more responsible for the activity of methanol synthesis than the former one. It is found that the composition and structure of the precursors altered obviously after the colour transition point. The experimental results showed that methanol synthesis is a structure-sensitive catalytic reaction.