Showing papers by "Tohoku University published in 1982"
TL;DR: It is shown in a umfied manner that there exist hnearume algorithms for many combinatorial problems ff an input graph is restricted to the class of series-parallel graphs.
Abstract: A series-parallel graph can be constructed from a certain graph by recurslvely applying \"series\" and \"parallel\" connections The class of such graphs, which Is a well-known model of series-parallel electrical networks, is a subclass of planar graphs It is shown in a umfied manner that there exist hnearume algorithms for many combinatorial problems ff an input graph is restricted to the class of series-parallel graphs. These include 0) the decision problem with respect to a property characterized by a finite number of forbidden graphs, (u) the mlmmum edge (vertex) deletion problem with respect to the same property as above, and (Ul) the generalized matching problem Consequently, the following problems, among others, prove to be hnear-tlme computable for the class of series-parallel graphs. (I) the minimum vertex cover problem, (2) the maximum outerplanar (reduced) subgraph problem, (3) the minimum feedback vertex set problem, (4) the maximum (induced) hne-subgraph problem, (5) the maximum matching problem, and (6) the maximum disjoint triangle problem.
293 citations
TL;DR: In this paper, a pressureless sintering of SiC with oxide additives was performed at 2100°C with the products of the reaction of Al(OH)3 with HCl and of Y(OH3 with HCOOH.
Abstract: Pressureless sintering of SiC was accomplished at 2100°C with oxide additives. These additives were the products of the reaction of Al(OH)3 with HCl and of Y(OH)3 with HCOOH. These reaction products were dissolved in water and mixed with submicrometer β-SiC. A mixture of equal weights of these additives was effective for the sintering of SiC.
241 citations
TL;DR: In this paper, the effects of localization on two-dimensional superconductors have been investigated by taking into account quantum corrections to the theory of dirty superconductions in the order of ( e F τ 0 ) -1 where e F and τ 0 are the Fermi energy and the relaxation time of an electron, respectively.
Abstract: Effects of localization on two-dimensional superconductors have been investigated by taking into account quantum corrections to the theory of dirty superconductors in the order of ( e F τ 0 ) -1 where e F and τ 0 are the Fermi energy and the relaxation time of an electron, respectively. The mean field superconducting transition temperature is seen to be reduced by localization. This is because the Coulomb repulsive interaction is enhanced and the density of states of electrons is depressed in dirty systems. Recent experiments by Kobayashi et al. on granular films of tin are discussed in this context.
195 citations
TL;DR: The ability of both GL and GA to induce IFN in mice was investigated and the possibility that GL induces IFN was proposed in the light of GL's clinical effect on hepatitis patients and of the fact that its structure resembles that of hydrocortisone.
Abstract: Licorice extract is an herbal drug which has long been used as a demulcent and elixir in Chinese medicine. One of the main active components of licorice extract is glycyrrhizin (GL), a kind of saponin. The biological effects of GL and its aglycone, glycyrrhetinic acid (GA), have been extensively studied. Their anti-inflammatory (5), anti-ulcerous (3), and antiviral (14) effects have been reported from 1948 (15) to 1979 (14). Moreover, a preparation of GL combined with glycine and cysteine (SNMC), has been widely and successfully used in Japan as an antihepatitis drug (6, II, 19), although its mechanism of pharmacological action remains unclear. Recently, interferon (IFN) with or without adenine arabinoside (Ara-A) has been used to treat hepatitis B patients (4, 7). Studies show that IFN consistently decreases the level of either DNA polymerase or hepatitis B surface antigen in hepatitis patients. There are also many reports which suggest that some irnmunopotentiators induce IFN (13) and explain their antiviral activity in vivo as interferon mediated (8, 16, 18). Therefore, in the light of GL's clinical effect on hepatitis patients and of the fact that its structure resembles that of hydrocortisone, the possibility that GL induces IFN was proposed. In this study we investigated the ability of both GL and GA to induce IFN in mice. Sixto 8-week-old male DDI mice obtained from the Institute for Experimental Animals, Tohoku University School of Medicine, were used in this experiment. Six-week-old male C3H, ddY, CDF-l, C57BL, BALB/c, and athymic nude mice (nujnu) of BALB/c background were obtained from the Funabashi Farm Co., Ltd., and were used to study the effect of the different mouse strains on interferon induction. GL and GA were supplied by Minophagen Pharmaceutical Co. Drugs were dissolved in 0.01 M phosphate buffered saline (PBS) and adjusted to pH 7.2 with I N sodium hydroxide. Pooled sera obtained from three mice were tested for anti-viral activity, which was determined by the 50% plaque reduction method on L-929 monolayer cell cultures with vesicular stomatitis virus (VSV) and was expressed in international reference units based on NIH reference mouse IFN (Catalog No. 002-904-511) (12).
195 citations
TL;DR: In this article, the fundamental properties of hexagonal ferrites with magnetoplumbite structure were discussed, and the most typical way to obtain the ferrimagnetic hexagonal oxides as powder or in a sintered polycrystalline state is the solid-state reaction of heating the mixtures of constituent oxides or of compounds that are easily changed to oxides by heating.
Abstract: Publisher Summary This chapter discusses the fundamental properties of hexagonal ferrites with magnetoplumbite structure. Ferrimagnetic properties of the magnetoplumbite type compounds are naturally based on the superexchange interaction of Fe–O–Fe, so that no remarkable effect on the magnetic properties would be expected by the replacement of a Ba ion. However, the properties could be influenced to some extent by the changes in the distance or the angle between Fe–O–Fe arising from the substitution, leading to differences among BaM, SrM, and PbM. Further, the most typical way to obtain the ferrimagnetic hexagonal oxides as powder or in a sintered polycrystalline state is the solid–state reaction of heating the mixtures of constituent oxides or of compounds that are easily changed to oxides by heating. BaCO 3 , SrCO 3 , PbO, and α-Fe 2 O 3 are generally used as starting materials, but oxalates, sulfates, chlorides, nitrates, or hydroxides are also used for specific purposes. Proper reaction temperature, atmosphere, and cooling conditions should be chosen according to the phase diagrams. However, single-phase M type compounds can be usually obtained by heating in air between 800 °C and 1200°C, and just removing from the furnace.
181 citations
TL;DR: A relative uncoupling between oxygen consumption and blood flow was observed in all tumours as indicated by a decreased regional fractional extraction of oxygen (rOER), which suggests that a major proportion of these tumours had sufficient blood supply to meet oxygen metabolic demand.
Abstract: Regional cerebral blood flow and oxygen utilisation have been studied in 8 patients with brain tumours using continuous inhalation of C15O2 and 15O2 and positron emission tomography. The methods used to analyse the regional cerebral pathophysiology are presented. A relative uncoupling between oxygen consumption and blood flow was observed in all tumours as indicated by a decreased regional fractional extraction of oxygen (rOER). This suggest that a major proportion of these tumours had sufficient blood supply to meet oxygen metabolic demand. A decrease of blood flow in grey matter was found both in the affected and contralateral hemispheres of the brain. Matched reductions of flow and oxygen utilisation were observed in oedematous tissue.
174 citations
TL;DR: In this article, the authors define the Abelian component of the gauge field as a gauge-invariant object in the Yang-Mills theory and demonstrate that quarks as well as gluons are confined by electric vortices.
Abstract: We define the Abelian component of the gauge field as a gauge-invariant object in the Yang-Mills theory. Then, by assuming that the Abelian component dominates in the theory at a long-distance scale, we demonstrate that quarks as well as gluons are confined by electric vortices. The vacuum structure is shown to depend on resolution $R$. That is, the vacuum has two phases in $R$ and monopole condensation occurs for $R\ensuremath{\ge}{R}_{c}$. The string tension of mesons is obtained as ${\ensuremath{\sigma}}_{q}=\frac{{{g}_{c}}^{2}}{3\ensuremath{\pi}{{R}_{c}}^{2}}$, where ${g}_{c}$ is the effective coupling constant at the critical resolution ${R}_{c}$. We estimate ${{R}_{c}}^{\ensuremath{-}1}$ to be 0.6 GeV in the presence of static quarks, and the bag constant ${B}^{\frac{1}{4}}$ to be 0.2-0.4 GeV. We also derive a relation ${\ensuremath{\alpha}}_{g}^{\ensuremath{'}}=\frac{1}{3}{\ensuremath{\alpha}}^{\ensuremath{'}}$ between Regge slopes of mesons (${\ensuremath{\alpha}}^{\ensuremath{'}}$) and of gluonia (${\ensuremath{\alpha}}_{g}^{\ensuremath{'}}$). This relation agrees with experimental data remarkably well provided that gluonia are identified with states lying on the Pomeranchuk trajectory.
159 citations
TL;DR: In this article, it was demonstrated that the tensile strength of the Fe75Si10Bl5 amorphous wire increases by the replacement of iron with a small amount of tantalum, niobium, tungsten, molybdenum, or chromium without detriment to the formation tendency of an amorphus wire.
Abstract: Amorphous wires with high strength and good ductility have been produced in Fe-Si-B alloy system by the modified melt-spinning technique in which a melt stream is ejected into a rotating water layer. These wires have a circular cross section and smooth peripheral surface. The diameter is in the range of about 0.07 to 0.27 mm. Their Vickers hardness (Hv) and tensile strength (σf) increase with silicon and boron content and reach 1100 DPN and 3920 MPa, respectively, for Fe70Si10B20, exceeding the values of heavily cold-drawn steel wires. Fracture elongation(e
f
), including elastic elongation, is about 2.1 to 2.8 pct. An appropriate cold drawing results in the increase of σf and ef by about eight and 65 pct, respectively. This increase is interpreted to result from an interaction among crossing deformation bands introduced by cold drawing. The undrawn and drawn amorphous wires are so ductile that no cracks are observed, even after closely contacted bending. Further, it is demonstrated that the σf of the Fe75Si10Bl5 amorphous wire increases by the replacement of iron with a small amount of tantalum, niobium, tungsten, molybdenum, or chromium without detriment to the formation tendency of an amorphous wire. Such iron-based amorphous wires are attractive as fine gauge, high strength materials because of their uniform shape and superior mechanical qualities.
158 citations
TL;DR: It is suggested that much of the data can be explained by a habitat specialist-generalist model, with high heterozygosities in specialists and low heterozygOSities in generalists, but that this is only one of a mosaic of factors which influence genetic variation.
Abstract: Genetic variation was reviewed in 106 species of marine teleosts. Two heterozygosity estimates were used, one including all protein and enzyme loci and a second excluding the non-enzymatic protein loci. Mean heterozygosities are 0.055±0.036 based on all loci in 106 species and 0.060+0.038 based on enzymatic loci in 89 species. A significant negative correlation was noted between heterozygosity and the proportion of general protein loci included in the estimate. A comparison was made of heterozygosities among taxonomic orders and families, life zones, reproductive mode, geographical range and size. High levels of genetic variation are found in Clupeiformes, Atheriniformes, Pleuronectiformes, temperate pelagic, tropical, intertidal-sublittoral and wide-range species. Low levels of genetic variation are found in Gadiformes, Scorpaeniformes, temperate demersal, polar, and narrowrange species. The most striking differences in heterozygosities are between temperate demersal flatfishes and temperate demersal round fishes. It is suggested that much of the data can be explained by a habitat specialist-generalist model, with high heterozygosities in specialists and low heterozygosities in generalists, but that this is only one of a mosaic of factors which influence genetic variation.
154 citations
TL;DR: In this article, a method of efficient enzymatic hydrolysis of polyprenyl pyrophosphates was established, such as all-trans-octaprenyl and alltrans-nonapreny (solanesyl) pyrophophosphates.
151 citations
TL;DR: In this article, the magnetic structure and weak ferromagnetic magnetism of Mn 3 Sn were studied by polarized neutron diffraction at room temperature and it was shown that the spin structure has a triangular configuration of inverse geometry in the c-plane and the triangle rotates opposite to the rotation of the c -plane field component.
Abstract: The magnetic structure and weak ferromagnetism of Mn 3 Sn were studied by polarized neutron diffraction at room temperature. The flipping ratio was measured for a number of Bragg reflections by rotating the crystal about the scattering vector under a magnetic field of 8 kOe applied perpendicular to the scattering vector. It was found that the spin structure has a triangular configuration of inverse geometry in the c -plane and the triangle rotates opposite to the rotation of the c -plane field component. From the analysis of the anisotropy energy it was shown that the triangle of inverse geometry is stabilized by the Dzyaloshinski-Moriya interaction and the weak ferromagnetic moment appears from the mechanism that each spin in the inverse triangle tilts slightly toward its easy axis. It was also shown that the weak ferromagnetic moment rotates just opposite to the rotation of the triangle.
01 Dec 1982-Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology
TL;DR: Genetic analysis showed that theTre gene, whose locus is closely linked tocx (13.6) on theX chromosome, is responsible for the difference in the taste sensitivity to trehalose.
Abstract: A quantitative behavioral assay was developed for the measurement of taste responses to sugars inDrosophila. The amount of the intake of a sugar solution was measured colorimetrically after homogenization of flies which had consumed sugar solutions mixed with a food-dye. A two-choice method was utilized to determine the taste sensitivity to sugars. Two kinds of sugar solutions were marked with either blue or red food-dye and placed alternately in the wells of a micro test plate. Flies were allowed to choose between the two sugar solutions. By classifying and counting the coloured flies, the relative taste sensitivity could be determined. Employing these methods, a genetic dimorphism in the taste sensitivity to trehalose was found among some laboratory strains ofDrosophila melanogaster. No difference in the taste sensitivity to glucose, fructose and sucrose was found between the trehalose high-sensitivity (T-1) and the low-sensitivity (Oregon-R) strains. Trehalose concentration equivalent to 2 mmol/1 sucrose, in terms of stimulating activity, was 57 mmol/1 inOregon-R and was 10 mmol/1 inT-1. Genetic analysis showed that theTre gene, whose locus is closely linked tocx (13.6) on theX chromosome, is responsible for the difference in the taste sensitivity to trehalose.
TL;DR: In this paper, a double layer is produced in front of the plasma source and moves toward the collector during the limitation, and when the double layer arrives at the collector, the barrier dissolves and the current increases, causing a rise in potential along the whole plasma column.
Abstract: A negative potential barrier on the low-potential side of a moving double layer gives rise to a current limitation in a collisionless plasma terminated by a positively biased cold collector plate in a $Q$ machine. The double layer is produced in front of the plasma source and moves toward the collector during the limitation. When the double layer arrives at the collector, the barrier dissolves and the current increases, causing a rise in potential along the whole plasma column. The double layer then reforms at the source.
TL;DR: Polarized-neutron diffraction by Mn 3 Sn and Mn 3 Ge in magnetic field reveals that the spin triangle coincides with the c-plane, is the inversion of the atomic triangle, and rotates opposite to the rotation of the c -plane component of magnetic field as discussed by the authors.
TL;DR: A bacterial antitumor and immunopotentiating agent, OK-432, induced Interferon in the spleen cell cultures but not in the thymus cell cultures of various inbred strains of mice.
01 Sep 1982-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this article, the enthalpies of mixing liquid copper with liquid silver and with solid titanium, zirconium, and hafnium have been measured by high temperature reaction calorimetry at 1371 to 1373 K.
Abstract: The enthalpies of mixing of liquid copper with liquid silver and with solid titanium, zirconium, and hafnium have been measured by high temperature reaction calorimetry at 1371 to 1373 K. A least squares treatment of the data for copper-silver alloys yields the following expression for the molar enthalpy of mixing: ΔHmix = ϰAgϰCu(17.66 − 5.46 ϰAg) kJ mol−1. The enthalpies of solution of solid titanium, zirconium, and hafnium in dilute solutions in liquid copper are all exothermic; the following values were found: -2.0 kJ mol−1 for Ti, -52.5 kJ mol−1 for Zr, and -46.3 kJ mol−1 for Hf. These values are all significantly less exothermic than predicted by the semiempirical theory of Miedema. The enthalpies of formation of congruent melting intermetallic phases in the systems Cu-Ti, Cu-Zr, and Cu-Hf were measured by drop calorimetry or by solution calorimetry in liquid copper. The enthalpies of formation of the solid alloys have been compared with corresponding data for the liquid alloys.
TL;DR: In this article, the energy band structure of black phosphorus was calculated by using self-consistent pseudopotential method and the resulting band structure has the direct minimum gap at the point Z in the Brillouin zone in agreement with the result of the tight-binding approach.
Abstract: The energy band structure of black phosphorus is calculated by using self-consistent pseudopotential method. The resulting band structure has the direct minimum gap at the point Z in the Brillouin zone in agreement with the result of the tight-binding approach. Effective electron and hole masses and the level shift of the band edge by pressure are calculated from the bands obtained. The pressure dependence of the energy gap is in good agreement with experiment, but the anisotropy of the effective masses contradicts that of the electrical conductivity measured for the single crystal. The nature of the optical absorption edge is discussed in terms of the calculated band structure.
TL;DR: A simple formula for calculating the probability of excluding paternity with a system determined by any number of codominant alleles was devised, which can be used when the genetic system is much more complicated.
TL;DR: In this paper, it was shown that H-protein brings about a conformational change of P-protein, which may be relevant to the expression of the decarboxylase activity.
Abstract: The glycine cleavage enzyme system is composed of four different proteins tentatively called P-protein, H-protein, T-protein and L-protein, and catalyzes the following reaction reversibly: Glycine + tetrahydrofolate + NAD+ ⇋ 5, 10-methylene-tetrahydrofolate + NH3 + CO2 + NADH + H−
Glycine decarboxylase, tentatively called P-protein, is able by itself to catalyze glycine decarboxylation, yielding methylamine as product, but at an extremely low rate. P-Protein alone is also able to catalyze slightly the exchange of carboxyl carbon of glycine with CO2. However, the rates of the P-protein-catalyzed reactions are greatly increased by the co-existence of aminomethyl carrier protein, a lipoic acid-containing enzyme tentatively called H-protein. Several lines of evidence suggest that H-protein brings about a conformational change of P-protein which may be relevant to the expression of the decarboxylase activity of P-protein and that the functional glycine decarboxylase may be an enzyme complex composed of both P-protein and H-protein. H-Protein seems to play a dual role in the glycine decarboxylation; the one as a regulatory protein of P-protein, and the other as an electron-pulling agent and concomitantly as a carrier of the aminomethyl moiety derived from glycine. The idea that H-protein functions as a modulator of P-protein was further supported by the study of a patient with nonketotic hyperglycinemia. The primary lesion in this patient appeared to consist in structural abnormality in H-protein; the H-protein purified from the liver of this patient was apparently devoid of functional lipoic acid. Nevertheless, H-protein from the patient could stimulate the P-protein-catalyzed exchange of the carboxyl carbon of glycine and CO2, although only to a limited extent. The observed activity should be independent of the functioning of lipoic acid and would be a reflection of a conformational change in P-protein brought about by H-protein. P-Protein was inactivated when it was incubated with glycine in the presence of II-protein, and the inactivation was completely prevented when bicarbonate was further added so as to allow the glycine-CO2 exchange to proceed. The inactivation was accompanied by a spectral change of P-protein. The inactivation of P-protein seemed to take place as a side reaction of the glycine decarboxylation and to reflect the formation of a ternary complex of P-protein, H-protein and aminomethyl moiety of glycine through a Schiff base linkage of the H-protein-bound aminomethyl moiety with the pyridoxal phosphate of P-protein.
TL;DR: High reproductive value, fast development rate, and short adult life span suggest that A. clausi may be r-selective when conditions are favorable, and facultative resting eggs act to maintain the population during unfavorable conditions, suggesting K-selection.
TL;DR: In this paper, the infrared absorption of p-nitrobenzoate, formed on Ag island film about 5 nm thick, is enhanced by a factor of the order of 10.
Abstract: By the use of an ATR technique we have found that the infrared absorption of p-nitrobenzoate, formed on Ag island film about 5 nm thick, is enhanced by a factor of the order of 10. Only vibrational modes involving a change in the dipole moment of the benzoate ion perpendicular to the macroscopic Ag surface are enhanced by p-polarized radiation alone, indicating the electric field of the evanescent wave polarized perpendicular to the Ag surface plays a dominant role in the infrared excitation process. A monolayer of stearic acid deposited on a Ag underlayer 5nm thick gave another example of the enhancement. Although the mechanism of enhancement is not fully elucidated, the existing model based on the collective electron resonances of Ag islands is not applicable to the present case, since it predicts the electron resonance can be excited irrespective of polarization state of infrared beam.
TL;DR: A simple method for the simultaneous assay of the activities of histidine and ornithine decarboxylases without using radioisotope substrates was used in this study and the results are discussed in relation to the actions of lipopolysaccharide.
TL;DR: The present data indicate that the defective insulin secretion is a primary derangement in a diabetic state of the spontaneous diabetes rat, and suggests the specific impairment of the recognition of glucose by the pancreatic beta-cells.
Abstract: Dynamics of insulin and glucagon secretion were investigated by using a new model of spontaneous diabetes rats produced by the repetition of selective breeding in our laboratories. The perfusion experiments of the pancreas showed that the early phase of insulin secretion to continuous stimulation with glucose was specifically impaired, although the response of the early phase to arginine was preserved. The glucose-induced insulin secretion in the nineth generation (F8) which had a more remarkably impaired glucose tolerance was more reduced than in the sixth generation (F5). No significant difference of glucagon secretion in response to arginine or norepinephrine was noted between the diabetes rats and control ones. The present data indicate that the defective insulin secretion is a primary derangement in a diabetic state of the spontaneous diabetes rat. This defect in the early phase of glucose-induced insulin secretion suggests the specific impairment of the recognition of glucose by the pancreatic beta-cells. The spontaneous diabetes rats are very useful as a model of disease for investigating pathophysiology of non-insulin dependent diabetes mellitus.
TL;DR: The DHPR assay on erythrocytes of dried blood spots can be easily applied to all newborn infants with hyperphenylalaninemia detected using the Guthrie tests, and will facilitate the quick and confirmative detection of DHPR deficiency among them.
Abstract: Enzymatic diagnosis of hyperphenylalaninemia due to a deficiency of dihydropteridine reductase (DHPR) has previously been made by assay on liver biopsy samples, cultured skin fibroblasts, cultured lymphoid cell lines, or peripheral leukocytes. These procedures have some disadvantages for the purpose of early diagnosis of the disease. A simple method of DHPR assay using erythrocytes or dried blood spots on filter papers is described. The mean DHPR activity erythrocytes of control subjects was 3.20 +/- 0.70 (SD) nmoles/min/mg of hemoglobin, those of two patients were undetectable, and those of obligate heterozygotes for DHPR deficiency were approximately 50% of the mean control value. The assay on erythrocytes required only a 5-microliters volume of whole blood for one test. The DHPR activities in dried blood spots on filter papers from 100 normal newborns were 5.77 +/- 1.16 nmoles/min per 5-mm diameter disc; those from normal older infants, children, and adults were 3.37 +/- 0.72 nmoles/min per disc; and those from two adolescent patients with DHPR deficiency were undetectable. No false-positive results were obtained. The stability of DHPR in dried blood on filter papers was enough to mail samples in an ordinary form to a specialist laboratory. The DHPR assay on erythrocytes of dried blood spots can be easily applied to all newborn infants with hyperphenylalaninemia detected using the Guthrie tests, and will facilitate the quick and confirmative detection of DHPR deficiency among them.
TL;DR: In this paper, the separation and determination of d- and l-naproxen in serum by high-performance liquid chromatography (HPLC) was described, based on pre-column derivatization with a newly developed chiral reagent, l-1-(4-dimethylamino-1napthyl)ethylamine (DANE) to form the diastereoisomeric amides.
TL;DR: In this paper, phonon dispersion curves of black phosphorus are calculated using the force constant model, in which the valence force model is assumed for intralayer interatomic interactions and the axially symmetric force model for interlayer ones.
TL;DR: The magneto-volume effect of the weak itinerant ferromagnet MnSi has been studied by measuring both the thermal expansion over a wide range of temperature and the forced volume megnetostriction at different temperatures as discussed by the authors.
Abstract: The magneto-volume effect of the weak itinerant ferromagnet MnSi has been studied by measuring both the thermal expansion over a wide range of temperature and the forced volume megnetostriction at different temperatures. The forced magnetostriction at 4.2 K as well as the magnetic thermal expansion at 10 kOe, Δω m ( H , T ) can well be described by a formula Δω m ( H , T )= K C Δ[ M ST ( H , T ) 2 ] with K C =1.5×10 -10 (mol/emu) 2 where Δ[ M ST ( H , T ) 2 ] is the change of square of magnetization by polarization of the d band. The spontaneous magnetostriction at 0 K, Δω m (0,0) is related to the spontaneous magnetization M (0,0) by \(\Delta\omega_{\text{m}}(0,0){\doteqdot}(2/5)KC\ M(0,0)^{2}\) with the same K C . Furthermore magneto-v olume effect becomes positive above T c . All of these features agree satisfactorily with those predicted by Moriya and Usami based on spin fluctuation theory.
TL;DR: In this paper, the effect of polyvinyl alcohol, added as a stabilizer to the continuous phase, on dispersed drop size distribution was investigated in suspension polymerization of styrene.
Abstract: Suspension polymerization of styrene was conducted to study the effect of polyvinyl alcohol, added as a stabilizer to the continuous phase, on dispersed drop size distribution. Transient drop size distributions were measured under several experimental conditions with dispersedphase volume fractions ranging from 0.1 to 0.5 and stabilizer concentrations from 0.3 to 10g/l. The experimental results show that at the early stage of the reaction, where the dispersed phase viscosity is lower than about 50 cp, drop size does not depend upon stabilizer concentration. Above this viscosity, stabilizer concentration influences on drop size. Whenever drop agglomeration occurs, drop size distribution reveals a bimodal form in which the lower drop size mode in the distribution maintains a constant drop diameter while the higher drop size mode moves toward a larger drop size. The experimental results may be accounted for by the hypothesis that the coalescence of dispersed drops above the maximum stable drop size for breakup is not effectively prevented by the stabilizer.