Abstract: An electrophotographic imaging member including a charge generating layer and a charge transport layer, the charge transport layer having two or more charge transporting molecules having ionization potentials within 0.2 electron Volts of each other. This imaging member has stress characteristics that reduces curling, cracking and delamination from the substrate.

Abstract: An electrophotographic photosensitive member is disclosed which has a photosensitive layer on a conductive support. The photosensitive layer contains an azo pigment of Formula (1):Ar--(--N.dbd.N--Cp).sub.n.Also, disclosed are an electrophotographic apparatus, a device unit, and a facsimile machine using the electrophotographic photosensitive member.

Abstract: A process for the preparation of hydroxygallium phthalocyanine and elements containing same which comprises the synthesis of a precursor halogallium phthalocyanine by the reaction of a diiminoisoindolene with gallium acetylacetonate; hydrolysis thereof to hydroxygallium phthalocyanine; and conversion of the resulting hydroxygallium phthalocyanine obtained to Type V hydroxygallium phthalocyanine by contacting said resulting hydroxygallium phthalocyanine with an organic solvent.

Abstract: Disclosed is a process for forming thin films of pigment compounds, comprising providing a solubilized pigment-Lewis acid complex contained in an aprotic organic solvent system and coating the solubilized pigment-Lewis acid complex containing solvent system on a substrate.

Abstract: Electrophotographic elements including near-infrared radiation absorbing sensitizers and selected near-infrared radiation absorbing additives exhibit a reduced tendency toward the formation of laser interference patterns. These elements can be utilized in electrophotographic imaging processes including the steps of electrostatically charging the element, imagewise exposing the charged element to near-infrared radiation to form an electrostatic latent image, developing the electrostatic latent image by applying charged toner particles to the element to produce a toned image, and transferring the toned image to a suitable receiver.

Abstract: A color filter formed in accordance with the invention is formed by depositing a thin film of organic pigment an on electrode by electrochemical methods. An organic pigment is included in an aqueous micellar solution that includes a surfactant that has redox reactivity. The surfactant preferably has a metallocene such as ferrocene at the hydrophobic terminal end group. A transparent substrate having a transparent electrode thereon is emersed in the micellar solution. Voltage is applied to the transparent electrode and the organic pigment will form on the transparent electrode. Conductive particles, polymer material or conductive polymer material can be included with or on the pigment. Alternatively, the polymer or conductive polymer can be layered.

Abstract: An electrophotographic photoreceptor is disclosed, which comprises an electrically conductive substrate having formed thereon at least a charge generating layer and a charge transporting layer, wherein said charge generating layer is formed using a dispersed coating liquid prepared by mechanically grinding a perylene pigment and dispersing the ground perylene pigment in water, an alcohol series solvent, or an acetic acid ester solvent. A process of producing the photoreceptor is also disclosed. The electrophotographic photoreceptor provides a long pot life and stabilized dispersibility and electric characteristics.

Abstract: A photosensitive material for electrophotography comprises a conductive support and a photosensitive layer formed on the conductive support, the photosensitive layer being made of X-type metal-free phthalocyanine, a resin binder, and an essential additive effective for improving electrophotographic or photosensitive characteristics or durability in repeated use wherein the X-type metal-free phthalocyanine is dispersed in the resin binder partly in a molecular state and partly in a particulate state. The essential additive includes electrolytically polymerized products, certain kinds of dyes, silane or polysilane compounds, hole and electron transport substances, titanyl or vanadyl phthalocyanine, electron acceptors, perylene compounds, amine derivatives, amino compounds, zinc oxide or the like.

Abstract: Oxytitanium phthalocyanine hydrate crystal and an electrophotographic photoreceptor using said crystal are disclosed. The structural formula of the crystal is TiOPc(H.sub.2 O).sub.n wherein Pc represents a phthalocyanine residual group, and n represents from 0.15 to 1; and the elemental analysis values of C, H and N are as follows: C: 65.0 to 66.3 %; H: 2.5 to 3.1 %; and N: 18.5 to 19.3 %.

Abstract: An photosensitive member suitable for use in the electrophotographic apparatus of reversal development-type is formed by an electroconductive support, a charge-generation layer and a charge-transport layer disposed in this order. The charge-generation layer comprises oxytitanium phthalocyanine and the charge-transport layer is formed in a thickness of 22 microns or larger. The oxytitanium phthalocyanine is highly sensitive so that a low dark-part potential of 600V or lower (absolute) is sufficient. Because of the low dark-part potential and the thick charge transport layer, image defect, such as fog and black spots are effectively suppressed.

Abstract: The present invention provides an electrophotographic photoreceptor high in sensitivity and endurance and highly resistant against oxidizing action with ozone or the like which comprises an electrically conductive support and, provided thereon, a light-sensitive layer which contains at least one azo compound containing a coupler component represented by the following formula [I] or [II]: ##STR1## wherein X represents a heterocyclic or aromatic ring residue which may have a substituent fusing with the benzene ring, Y represents a linkage group, R.sup.1 -R.sup.4 each represents a hydrogen atom or an alkyl group and R.sup.5 represents a hydrogen atom or an alkyl, aralkyl or acyl group which may have a substituent; ##STR2## wherein X and Y are as defined above and R.sup.6 and R.sup.7 each represents a hydrogen atom or an alkyl group which may have a substituent.

Abstract: An electrophotographic photoconductor is composed of an electroconductive support and a photoconductive layer formed thereon which contains a charge generating material and a charge transporting material. The charge generating material is composed of a particular triasazo compound and a particular disazo compound. A photoconductive composition useful as a photoconductive material is also composed of the trisazo compound and the disazo compound.

Abstract: A photosensitive member for electrophotography has a photosensitive layer provided on a photoconductive substrate. The photosensitive layer contains at least one of indole derivatives represented by a chemical formula (I): ##STR1## wherein R.sub.1 and R.sub.2 are members selected from a group consisting of hydrogen atom and alkyl, aralkyl, allyl and alkoxy groups having 1-9 carbon atoms (but R.sub.1 and R.sub.2 do not stand for hydrogen atoms at the same time); R.sub.3 is a member selected from a group consisting of hydrogen and halogen atoms and alkyl and alkoxy groups having 1-3 carbon atoms; X is a member selected from a group consisting of alkylen, allylen, carbonyl, sulfonyl, sulfinyl and sulfide groups and oxygen atom; and n stands for an integer of 0 or 1.

Abstract: An electrophotographic photoreceptor comprises an .alpha.-form copper phthalocyanine composition, which is obtained by treating a copper tetranitrophthalocyanine and copper phthalocyanine simultaneously to convert the crystalline form into .alpha.-form, and a photoconductive squarylium compound as the photoconductive material, and the ratios of the copper tetranitrophthalocyanine and the squarylium compound to the .alpha.-form copper phthalocyanine composition are limited to a particular range. The photoreceptor has a high photosensitivity and an excellent durability.

Abstract: A phthalocyanine mixed crystal comprising a halogenated indium phthalocyanine and a halogenated gallium phthalocyanine and an electrophotographic photoreceptor containing the phthalocyanine mixed crystal. The phthalocyanine mixed crystal is a charge generating material which provides an electrophotographic photoreceptor excellent in sensitivity, stability on repeated use, and environmental stability.

Abstract: Crystals of chlorogallium phthalocyanine, having distinct diffraction peaks at (i) 7.4.degree., 16.6.degree., 25.5.degree. and 28.3.degree., (ii) 6.8.degree., 17.3.degree., 23.6.degree. and 26.9.degree., or (iii) 8.7.degree. to 9.2.degree., 17.6.degree., 24.0.degree., 27.4.degree. and 28.8.degree. of the Bragg angle (2.theta..+-.0.2) to a CuK.alpha. characteristic X-ray; a photoconductive material for electrophotographic photoreceptor comprising the chlorogallium phthalocyanine; and an electrophotographic photoreceptor comprising an electroconductive support having thereon a light-sensitive layer containing at least one or more of chlorogallium phthalocyanine crystals. The electrophotographic photoreceptor has excellent sensitivity and durability.

Abstract: An electrophotographic photoconductor is composed of an electroconductive substrate and a photoconductive layer formed thereon, the photoconductive layer includes a dipyrenylamine derivative of formula (I): ##STR1## wherein R represents an alkyl group with 1 to 12 carbon atoms, which may have a substituent, or an aryl group which may have a substituent. Novel dipyrenylamine derivatives of formula (I), in which R is --ph--(R.sup.4)n, wherein, ph is a phenyl group, R.sup.4 is hydrogen, an unsubstituted or substituted alkyl group having 1 to 12 carbon atoms, an unsubstituted or substituted alkoxyl group having 1 to 12 carbon atoms, n is an integer of 1 to 5, and when n is 2 to 5, R.sup.4 may be the same or different, which are for use in the photoconductive layer of the electrophotographic photoconductor, are synthesized.

Abstract: An electrophotographic photoreceptor comprising a conductive substrate having provided thereon a photoconductive layer is disclosed, said photoconductive layer containing a high polymeric compound comprising a repeating unit comprised of a tetracarboxylic acid anhydride skeleton and a divalent organic group skeleton having an aromatic nucleus, said two skeletons being bonded via a nitrogen atom. Said high polymeric compound is formed by co-deposition of a tetracarboxylic acid anhydride compound and an aromatic diamine compound. The photoreceptor exhibits high sensitivity, high durability, and excellent image quality retention even when used repeatedly or in a high humidity environment.

Abstract: An electrophotographic photoreceptor having a charge generation material is disclosed. The charge genaration material is mixed crystals of a titanylphthalocyanine and a vanadyl phtalocyanine, which have a characteristic peak at a Bragg angle (2.theta.) of 27.2.+-.0.2.degree. in an X-ray diffraction spectrum with a Cu-K .alpha. ray (wave length: 1.541 .ANG.) and having other specific physical property. The photoreceptor is suitably used in a printer or photocopying machine.

Abstract: A process for storing information in an organic recording layer which, when treated locally with an organic solvent in accordance with the input of information, is able to change its absorption spectrum and/or its photoconductivity such that information can be produced or stored at the treated areas of said layer, wherein the organic solvent is solid at room temperature and is present in the recording layer, or by decomposition of a solid organic precursor which is present in the recording layer, and said solvent is vaporized or melts by the action of laser beams in accordance with the input of information, or said precursor is decomposed by the action of laser beams in accordance with the input of information.The stored information can be read out with a photodetector in the visible or near NIR range or with a built-in electrode system.

Abstract: An electrophotographic photoreceptor is disclosed. The photoreceptor comprises a conductive substrate and a photosensitive layer provided on the substrate. The photosensitive layer comprises titanylphthalocyanine having a peak at a Bragg angle 2.theta. of 27.2.degree..+-.2.degree. in the Cu-K.alpha. X ray-diffraction spectrum thereof and an alkyldiol which has 3 to 12 carbon atoms and the two hydroxyl group is bonded to carbon atoms arranged at different position in the molecular thereof. The amount of the diol is 0.1 to 1000 parts by weight per 100 parts by weight of the titanyl-phthalocyanine.

Abstract: A process for the preparation of a more perfect crystalline form of the Type I polymorph of titanyl phthalocyanine which comprises dissolving a precursor titanyl phthalocyanine Type I in a solution of trihaloacetic acid and alkylene chloride; adding the resultant solution to a solvent thereby enabling precipitation of Type X titanyl phthalocyanine; separating the titanyl phthalocyanine Type X from the solution; followed by a first washing with an organic solvent and a second washing with water; slurrying the resulting Type X titanyl phthalocyanine in an organic solvent enabling conversion of said Type X to Type IV titanyl phthalocyanine; and thereafter, subjecting the Type IV titanyl phthalocyanine obtained to treatment with an organic solvent to enable said crystalline form of titanyl phthalocyanine Type I.

Abstract: A layered photoreceptor is composed of a substrate, an extrinsic pigment layer that has been sensitized disposed over the substrate, and a charge transport polymer in contact with the pigment layer. A method for producing a photoreceptor comprises depositing a layer of sensitizing electron donor material in a polymer binder on a substrate. An extrinsic pigment layer is deposited on the layer of sensitizing electron donor material. A charge transport layer is deposited on the pigment layer.

Abstract: An electrophotographic photoreceptor is provided with a photosensitive layer, which contains an azo compound represented by the following g general formula (1): ##STR1## wherein A means a coupler residuum having phenolic OH radicals, R.sub.1 and R.sub.2 designate, respectively, a radical of an integer of, both, m=0.about.4, n =0.about.4, selected from the group consisting of hydrogen, halogen atoms, alkyl group, alkoxy group, and di-substituted amino group.The electrophotographic photoreceptor of this invention has excellent electrification characteristics, sensitivity characteristics and image-forming property as well as good sensitivity. In addition, its sensitivity and electrification characteristics undergo less variations even when employed repeatedly. It also undergoes little light-induced fatigue. It has high weatherability.

Abstract: An electrophotographic recording material which comprises an electrically conductive support having thereon a photoconductive layer, characterized in that said layer contains one or more 1,2-dihydroquinoline compounds corresponding to the following general formula (A): ##STR1## wherein: each of R.sup.1 and R.sup.2 (same or different) represents a C.sub.1 -C.sub.6 alkyl group,Y represents a polycyclic aromatic nucleus, including said nucleus carrying one or more non-ionic substituents, andZ represents the atoms necessary to close an adjacent aromatic nucleus or ring system, including such nucleus or ring system substituted with one or more substituents of non-ionic character.

Abstract: An electrophotographic photoreceptor comprising an electrically conductive substrate and a photoconductive layer formed thereon, wherein said photoconductive layer contains a compound of the formula ( I ): ##STR1## wherein R.sup.1 to R.sup.18 are respectively and independently a hydrogen atom, a halogen atom, a saturated or unsaturated aliphatic hydrocarbon group, an aromatic hydrocarbon group, an alkoxy group, an aryloxy group, a dialkylamino group or a diarylamino group, wherein the aliphatic hydrocarbon group, the aromatic hydrocarbon group, the alkoxy group, the aryloxy group, the dialkylamino group and the diarylamino group may have substituents, X is a bivalent hydrocarbon group which may have substituents, each of A.sup.1 and A.sup.2 is a saturated or unsaturated aliphatic hydrocarbon group or an aromatic hydrocarbon group, or is bonded to R.sup.5 or R.sup.

Abstract: A novel dichlorotin phthalocyanine crystal having distinct diffraction peaks at 8.5.degree., 11.2.degree., 14.5.degree., and 27.2.degree. of the Bragg angles (2.theta..+-.0.2) in the X-ray diffraction spectrum; process for producing the dichlorotin phthalocyanine crystal, comprising mechanically grinding a known dichlorotin phthalocyanine crystal together with an inorganic salt, followed by, if desired, a solvent treatment; an electrophotographic photoreceptor containing, in the photosensitive layer thereof, the dichlorotin phthalocyanine crystal; and a coating composition for producing an electrophotographic photoreceptor, comprising the dichlorotin phthalocyanine crystal, a binder resin, and an acetic ester solvent. The photoreceptor exhibits high sensitivity and excellent durability. The coating composition maintains the dichlorotin phthalocyanine crystal in its desired form either while being prepared or after being coated.

Abstract: A novel phthalocyanine mixed crystal comprising a dihalogenotin phthalocyanine and a halogenogallium phthalocyanine and an electrophotographic photoreceptor containing the same are disclosed. The phthalocyanine mixed crystal preferably has an intense X-ray diffraction peak at a Bragg angle (2.theta..+-.0.2.degree.) of 26.9. The phthalocyanine mixed crystal is useful as a charge generating material which provides an electrophotographic photoreceptor excellent in sensitivity, stability on repeated use, and environmental stability.

Abstract: An image readout device having a plurality of readout elements for converting image into electrical signals, each element having a photoconductive layer and a pair of electrodes which contact the photoconductive layer, and between which the layer is disposed. The photoconductive layer contains a charge generation material and a charge transport material. Oxytitanium phthalocyanine is used as the charge generation material.

Abstract: A layered photoconductive imaging member comprised of a supporting substrate, a photogenerating layer and a charge transport layer, and wherein the photogenerating layer contains Type IV titanyl phthalocyanine obtained by a process which comprises the addition of an oxytitanium phthalocyanine containing a mixture of Type I and Type II titanyl phthalocyanine polymorphs, or a substantially pure Type II titanyl phthalocyanine polymorph to a solvent comprised of a trihaloacetic acid and an alkylene halide; adding the resultant solution to a mixture which enables precipitation of Type X oxytitanium phthalocyanine; separating the Type X oxytitanium phthalocyanine from the solution; and thereafter subjecting the Type X oxytitanium phthalocyanine obtained to treatment with a halobenzene, followed by the separation of the said Type IV oxytitanium phthalocyanine.

Abstract: A process for preparing an electrophotographic imaging member having a coating of photoconductive particles dispersed in a polymerizable film forming monomer, which when polymerized forms a charge generating layer.

Abstract: A layered imaging member comprised of a photogenerating layer of titanyl phthalocyanine prepared by depositing amorphous titanyl phthalocyanine on a substrate maintained at a temperature of from below 25.degree. to about minus 30.degree. C.; and contacting the substrate product with an aliphatic alcohol.

Abstract: A multi-layered electrophotographic element providing significantly improved properties, especially for use in photocopying and printing, which comprises a conductive support carrying a photoconductive layer comprising a photoconductive charge generating layer and a charge transporting layer on the charge generating layer. The charge generating photoconductive layer comprises a mixture of charge generating perylene pigments of the following structures ##STR1## wherein the mixture of perylene pigments is selected from pigment mixtures of a perylene of structure 1 with a perylene of structure 2, pigment mixtures of perylenes of structure 1 and pigment mixtures of perylenes of structure 2.

Abstract: A method for making photosensitive materials of the positive charge type which are useful in electrophotography is described. In the method, X-type and/or .tau.-type phthalocyanine is at least partially dissolved in a solvent along with a resin binder or in a solution of the resin binder by which good photosensitive characteristics are obtained. The photosensitive material obtained by the method may be of a single-layer or a double-layer type. A photosensitive material having an improved ozone resistance is also disclosed. The material makes use of a resin binder having vinylphenol units therein.

Abstract: A layered photoconductive imaging member comprised of a supporting substrate, a photogenerator layer comprised of perylene photoconductive pigments dispersed in a resin binder mixture comprised of at least two polymers, and a charge transport layer.

Abstract: Disclosed is the X polymorphic form of titanyl phthalocyanine.

Abstract: An electrophotographic photoreceptor is disclosed. The photoreceptor comprises a conductive layer and provided thereon, a photoreceptor layer comprising a carrier generation layer containing 100 parts by weight of a polycyclic quinone compound and 0.

Abstract: An organic, positive-charging photoconductor for laser printers is disclosed. The photoconductor has a conductive substrate, a hydroxy-containing binder which forms a layer greater than or equal to about 1 micron thick on the substrate, a phthalocyanine pigment uniformly distributed throughout said binder, and a reactive stabilizer containing silicon, also uniformly distributed throughout said binder. The silicon-containing stabilizer reacts with the hydroxy group in the binder, the effect of which is to improve the electrical stability of the photoconductor in the severe laser printing electrophotographic environment, and to improve surface release characteristics of the photoconductor for more efficient toner image transfer.

Abstract: The object of this invention is to provide a novel compound suited for use as a piezochromic material.This invention relates to a crystal comprising an indolinospirobenzothiopyran derivative of the following general formula and its ring opened isomer. ##STR1## wherein R.sup.1 stands for C.sub.1-20 alkyl, aralkyl, methacryloxymethyl or a methacryloxyethyl; R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6 and R.sup.7 may for example be hydrogen; R.sup.8 may for example be hydrogen or methacryloxymethyl.The invention further relates to a process for producing the crystal.

Abstract: The photoconductor for electrophotography comprises an electroconductive substrate and a photosensitive layer formed on the substrate. The photosensitive layer may be a monolayer or function-separated laminate type one which comprise a charge generating layer and a charge transporting layer laminated one on another. The charge generating layer contains a specified benzidine compound represented by general formula (I) below as the charge transporting substance. ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4, which are the same or different, each represent independently an aryl group, an alkylaryl group, an alkoxyaryl group or a halogenated aryl group provided that R.sub.1 and R.sub.2, or R.sub.3 and R.sub.4, or both combine and form a condensed aromatic group with the nitrogen atom to which they are bonded, respectively; R.sub.5 and R.sub.6 each represent independently a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom.

Abstract: A coated material comprising a substrate which is coated with a layer of a pyrrolopyrrole of formula I ##STR1## wherein R.sub.1 and R.sub.2 may be 4-pyridyl and X.sub.1 and X.sub.2 are O, said compound of formula I being at least partially in the form of a salt of a strong acid, is suitable for use as an optical recording material and, owing to its electrical conductivity and photoconductivity, as antistatically treated material, as sensor, photoreceptor and solar battery.

Abstract: A photoconductor contains octa-substituted phthalocyanines in a charge generation layer. The photoconductor shows good sensitivity in the infra-red region of the electromagnetic spectrum from about 600 nm to about 900 nm.

Abstract: A photosensitive material for electrophotography which comprises a conductive support, and a charge transport layer and a charge generation layer formed on the conductive support, is described. The charge generation layer is formed from a dispersion which is obtained by mixing X-type and/or .tau.-type metal-free phthalocyanine, with or without at least one other charge generation agent, and a resin binder in a solvent, which is capable of dissolving at least a part of X-type and/or .tau.-type metal-free phthalocyanine, to such an extent that a ratio between X-ray diffraction peak intensities at about 7.5.degree. and at about 9.1.degree. is in the range of 1:1 to 0.1:1. When the at least one other charge generation agent is used in combination, the charge generation layer is formed on the conductive support on which the charge transport layer is formed. If such other agent is not used, the charge generation layer is formed on the charge transport layer with a certain thickness.

Abstract: A dichlorotin phthalocyanine crystal showing, in the X-ray diffractometry using a CuK.sub..alpha. ray, a peak at a Bragg angle (2.theta..+-.0.2.degree.) of 28.2.degree. with any other peak(s) observed at a Bragg angle(s) between 25.degree. and 30.degree. having an intensity of not more than 30% of that of the peak at 28.2.degree.. The crystal is useful as a photoconductive material having sensitivity in the longer wavelength region. The electrophotographic photoreceptor containing the crystal exhibits high sensitivity and excellent durability.

Abstract: A photosensitive recording material which comprises an electrically conductive support having thereon a layer containing a charge transporting compound (n-CTM-compound) capable of accepting and transporting electrons obtained by radiation-activated charge-generation in a charge generating compound (CGM-compound) present in said material, wherein said n-CTM-compound corresponds to a general formula (A), (B), or (C) as defined in the description.

Abstract: An electrophotographic imaging member including a charge generating layer and a heterogeneous charge transport layer, the charge transport layer having regions of charge transport and inactive regions and the charge transporting regions are in contact with each other. This imaging member has characteristics that enable high quality and high contrast imaging.

Abstract: Disclosed are a phthalocyanine composition which comprises having main diffraction peaks at 7.5.degree., 22.5.degree., 24.3.degree., 25.3.degree. and 28.6.degree. of Bragg angles (2.theta..+-.0.2.degree.) in an X-ray diffraction spectrum with Cu K.alpha., a process for preparing the same, an electrophotographic photoreceptor using the same and a coating solution for a charge generation layer containing the same.

Abstract: Disclosed are novel crystals of hydroxyindium phthalocyanine, having distinct diffraction peaks at the particular angles of the Bragg angle (2.theta..+-.0.2) in the X-ray diffraction pattern. An electrophotographic photoreceptor comprising an electroconductive support having thereon a light-sensitive layer containing at least one of an amorphous hydroxyindium phthalocyanine and the above hydroxyindium phthalocyanine crystals. The electrophotographic photoreceptor has excellent sensitivity and durability.

Abstract: A phthalocyanine mixed crystal comprising a halogenated indium phthalocyanine and a halogenated gallium phthalocyanine and an electrophotographic photoreceptor containing the phthalocyanine mixed crystal. The phthalocyanine mixed crystal is a charge generating material which provides an electrophotographic photoreceptor excellent in sensitivity, stability on repeated use, and environmental stability.

Abstract: Crystals of hydroxygallium phthalocyanine, a method of preparing the crystals, a photoconductive material containing the crystals, and an electrophotographic photoreceptor having the material. The photoreceptor has excellent electrophotographic characteristics. The crystals of hydroxygallium phthalocyanine have distinct diffraction peaks at (i) 7.5.degree., 9.9.degree., 12.5.degree., 16.3.degree., 18.6.degree., 25.1.degree. and 28.3.degree., or (ii) 7.7.degree., 16.5.degree., 25.1.degree. and 26.6.degree., or (iii) 7.9.degree., 16.5.degree., 24.4.degree. and 27.6.degree., or (iv) 7.0.degree., 7.5.degree., 10.5.degree., 11.7.degree., 12.7.degree., 17.3.degree., 8.1.degree., 24.5.degree., 26.2.degree. and 27.1.degree., or (v) 6.8.degree., 12.8.degree., 15.8.degree. and 26.0.degree. or (vi) 7.4.degree., 9.9.degree., 25.0.degree., 26.0.degree., and 28.2.degree. of the Bragg angle (2.theta..+-.0.2) in the X-ray diffraction spectrum.