Materials Literature
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The commensurate charge-density-wave state of $2H$-${\mathrm{TaSe}}_{2}$ can have hexagonal ($H$) or orthorhombic ($O$) symmetry. With use of a Landau theory it is shown that near the boundary between $H$ and $O$ states a discommensuration splits into two $H\ensuremath{-}O$ interfaces and thereby greatly lowers its en…
一般式 (Bi2O2)2+(Mem-1RmO3m+1)2-で表されるBi層状化合物の中, 一致溶融し, しかも比較的高いキュリー点を有する7種の化合物の組成, 及びこれに少量のPbO, Bi2O3, B2O3などを添加した組成の融液を, 白金るつぼ中で70°-140℃/cmの温度こう配下で0.7-2.9mm/hの速度で下から上に向け一方向に凝固した. その結果, いずれの組成, いずれの凝固条件の場合も, 分極軸のa軸あるいはb軸を凝固進行方向にほぼ完全にそろえたBi層状化合物の配向性多結晶体が得られた. これらの多結晶体の多くは, 空げき及びき裂をいくらか含んでいたが, (Bi2O2)(PbNb2O7) にPbO-Bi2O3-B…
Fluoropolymers possess a number of unusual properties which should prompt wide usage in marine applications: (1) exceptional resistance to the effects of water, sunlight and biological organisms, (2) non-wetting, fast-draining surfaces, (3) anti-adhesive surfaces, (4) low friction or dry-film lubricant properties, and…
Abstract Experimental observations of the cyclic deformation and temperature rise in Mallory tubes during testing are described. The analyses of the data explain the temperature rise in terms of heat generated by the cord and rubber during the cyclic deformation. Using the measured temperature rise and the heat genera…
On the basis of structural data of the disordered tetragonal phase of tanane, the Van der Waals intermolecular forces are computed for the 16 nearest neighbours of a given molecule. Considering first the molecular ordering in a « rigid » tetragonal lattice, the pair energies between neighbouring molecules are analysed…
An investigation of two gear steels, AISI 9310 and VASCO X-2, carburized to a depth of 1.524 mm, was conducted to evaluate the effect of materials processing parameters on the fatigue lives of these materials in rolling contact fatigue, in single-tooth bending fatigue, and, finally, in a four-square dynamometer gear t…
Chemical and cation exchange characteristics, x-ray and DTA study of coarse and fine soil clays from duny areas of western Rajasthan showed that fine clays contained smectite, mica, mica-smectite and kaolinite. In addition to these, dune soil clay had minor amount of interlayered smectite and chloritic minerals, where…
Preliminary laboratory experiments were carried out to obtain some informatio on the nature of potential carbon fiber emissions resulting from the machining and incineration of graphite/epoxy composites. Examination of residues by scanning electron microscopy following exposure of graphite fiber products in a laborato…
An approximate method enabling rapid calculation of critical size as a function of the ambient temperature for bodies of arbitrary shape under generalized boundary conditions is given. These boundary conditions apply when there is resistance to heat transfer both within and at the surface of the reactant. The approach…
Inclusions reduce Blochwall areas and increase free magnetic poles. Magnetostriction leads to stresses. Blochwall configurations and movement during magnetization changes are strongly affected by the mechanical properties. Especially important is the interaction of dislocation with Blochwalls. Magnetic Barkhausen meas…
Abstract The melting of alkali halides occurs probably at a critical mole fraction x c = 3.2 · 10 −4 of thermally created vacancies (Schottky defects). Using this value the formation entropy of Schottky defects is found to be s S = (962.1 K mol/kJ L/ T m – 16.1) k ( L, T m heat and temperature of fusion, respectively)…
With the aid of a derivative spectrophotometer, emission characteristics of formaldehyde from a methanol fueled S. I. engine were obtained. Formaldehyde and unburned methanol were measured at several distances along the exhaust tube for various air-fuel equivalence ratios and ignition timings. Experiments show that do…
The thermal-shock behavior of ZrO2-CaO and ZrO2-MgO pellets was investigated by immersing these pellets into liquid iron without preheating temperature or with preheating temperature. The moduli of rupture before and after the thermal-shock were measured by a three point bending technique. A good thermal-shock resista…
Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation William T. Brown; Numerical modeling of oblique hypervelocity impact using two‐dimensional plane…
A simple and rapid complexometric method for stepwise titration of calcium and magnesium, when present in unfavourable ratios, has been successfully worked out. The method is based on the direct titration of calcium of pH 12 with EDTA, using thymolphthaleincalcein indicator. The adsorption of metallochromic indicator…
Abstract Zirconium dioxide, prepared by thermal decomposition of zirconium nitrate, was heated in air at temperatures ranging from 573 to 1023 K. An analysis of nitrogen adsorption‐desorption isotherms on the resulting materials allowed determination of the corresponding specific surface area and porous texture. All o…
The niobium-tin system was investigated in the temperature range 1261-2076 K by measurement of tin vapor pressures with a simultaneous weight loss-mass-spectrometric technique. For the reaction Nb + 1/3Sn ..-->.. NbSn/sub 1///sub 3/, ..delta..H/sub f//sup 298/ was found to be -21.59 kJ/mol. The heat of solution of tin…
Fe-25Cr-7Ni-3Mo(A)およびFe-23Cr-6Ni(B)の2種類の二相ステンレス鋼を用いてσ相析出挙動におよぼす種々の因子の影響を調べ,以下の結果を得た.(1)B鋼はA鋼に比し,σ相の析出に2桁以上長い時間を要した.σ相の析出が非常に速いA鋼との差は,化学組成,特にσ相とγ相に相分離することが知られているσ相の化学組成の差に起因すると思われる.(2)冷間加工のみならず熱聞加工あるいは焼入歪みもσ相の析出を促進することがわかつた.中でも冷間加工による促進効果は顕著であり,α粒内での析出に加えてγ粒内でもσ相の析出が認められ,従来知られているα→σ+γの反応に加えてγ→σの反応も存在することが認められた.このような内部歪…
Presentamos aqui un catalogo de las Diatomeas espanolas no marinas citadas hasta Julio de 1981. Se mencionan 738 taxones.
In the physically stressful environment there are three major ways in which a material can respond to external forces. It can add the load directly on to the forces which hold the constituent atoms or molecules together. This occurs in simple crystalline (including polymeric crystalline) and ceramic materials, and suc…