Synthesis and Structure Determination of the Quaternary Zinc Nitride Halides Zn2NX1−yX′y (X, X′ = Cl, Br, I; 0 < y < 1)
The quaternary series Zn2NCl1−yBry and Zn2NBr1−yIy were synthesized from solid-liquid reactions between zinc nitride and the respective zinc halides in closed ampoules, and the evolution of their crystal structures was investigated by single-crystal and powder X-ray diffraction. Zn2NX1−yX′y (X, X′ = Cl, Br, I) adopts the anti-β-NaFeO2 motif in which each nitride ion is tetrahedrally coordinated by four zinc cations, and the halide anions are located in the voids of the skeleton formed by corner-sharing [NZn4] tetrahedra. While Zn2NCl1−yBry crystallizes in the acentric orthorhombic space group Pna21 (No. 33), isotypic to Zn2NX (X = Cl, Br), the structure of Zn2NBr1−yIy is a function of the iodide concentration, namely, Zn2NBr (Pna21) for low iodine content and Zn2NI (Pnma) for higher (y ≥ 0.38).
Darstellung und Kristallstruktur der Calciumnitridhalogenide Ca2NCl und Ca2NBr
Ca2NCl und Ca2NBr wurden als hellgraue, sehr gut kristalline Pulver aus Ca3N2 und CaX2 im Molverhaltnis 1:1 in Stahlampullen unter Argon dargestellt (50 h 740°C, 15 h 1 000°C bzw. 40 h 950°C). Braunlich transparente Einkristalle erhielt man durch 25tagiges Tempern der Praparate in Molybdanampullen bei 1 125°C. 
 
 
 
Die Verbindungen kristallisieren im Anti-α-NaFeO2-Typ (R3m, Ca2NCl: a = 366,61(2) pm, c = 1971,1(4) pm, c/a = 5,377(2), Z = 3, dro = 2,815 g · cm−3, d = 2,77; Ca2NBr: a = 371, 66(3) pm, c = 2055, 8(4) pm, c/a = 5, 531(2), dro = 3,526 g · cm−3, d = 3,51). N3− und X− bilden zusammen eine rhomboedrisch verzerrte kubisch dichteste Anionenpackung mit der Schichtabfolge X−N3−X−N3−…. Ca2+ ist auf N3− zugeruckt, wodurch Ca2N+-Schichtpakete entstehen, die durch X− zusammengehalten werden. 
 
 
 
Preparation and Crystal Structure of the Calcium Nitride Halides Ca2NCl and Ca2NBr 
 
 
 
Ca2NCl and Ca2NBr were prepared as well crystalline powders of light-grey colour by reaction of Ca3N2 and CaX2 in a molar ratio 1:1 in steel ampoules under argon (50 h 740°C; 15 h 1 000°C and 40 h 950°C, resp.). Brownish transparent single crystals were obtained by annealing specimens in molybdenum ampoules (25 d 1 125°C). 
 
 
 
The compounds crystallize in the anti-α-NaFeO2-structure (Crystallographic data: see “Inhaltsubersicht”). N3− and X− are rhombohedrally distorted cubic close packed. The sequence of the anionic layers is X−N3−X−N3−…. Ca2+ is shifted towards N3− so that Ca2N+ layers are formed which are held together by the halide ions.
Automatic classification of TV news articles based on telop character recognition
The purpose of this study is to develop a multimedia database system for TV news video data. TV news video data consist of speech, characters and images. In this study, telop characters are recognized and given to the news articles as indices for classification. At first, telop frames which include telop characters are detected and then the telop characters are extracted and recognized. Through morphological analysis of the recognized telop characters, keywords are extracted which consist of more than two characters. Their keywords are used as indices to classify the TV news articles. We carried out experiments for 30 days of NHK 5 minutes news and obtained 95.4% telop character extraction rate, 81.4% character recognition rate and 83.8% article classification rate. We improved the article classification rate by 43.4% through character recognition improvement from 44.1% to 81.4%.