1/8 PROBLEMS IN THE La-, Bi- AND Y-BASED CUPRATES AND NEW ANOMALIES IN THE OVERDOPED REGION OF THE La-BASED CUPRATE

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3546-3551 ◽  
Author(s):  
Y. KOIKE ◽  
M. AKOSHIMA ◽  
T. ADACHI ◽  
N. KAKINUMA ◽  
T. NOJI ◽  
...  
Keyword(s):  
Oxygen Content ◽  
Experimental Work ◽  
Low Temperatures ◽  
Hole Concentration ◽  
Spin Fluctuations ◽  
Slowing Down ◽  
Recent Experimental Work

Recent experimental work on the 1/8 problem by our group is reviewed not only in the La-based cuprate but also in the Bi- and Y-based ones. In the partially Zn-substituted Bi 2 Sr 2 Ca 1-x Y x( Cu 1-y Zn y)2 O 8+δ, we have found anomalous suppression of superconductivity at x=0.30-0.35, where the hole concentration per Cu p~1/8. Moreover, it has been revealed from the μSR measurements that the Cu-spin fluctuations exhibit slowing-down behavior at low temperatures in these samples. These results are suggestive of the stripe correlations of holes and spins tending to be pinned by Zn at p~1/8 in the Bi-nbased cuprate as well as in the La-based cuprate. In Y 1-x Ca x Ba 2 Cu 3 O 7-δ, the 60 K plateau of Tc has been found not to be correlated with the oxygen content but to be interpreted as being due to the suppression of superconductivity at p~1/8. Accordingly, we conclude that the 1/8 problem is common to all high-Tc cuprates with the CuO 2 plane. Moreover, we have found transport and Tc anomalies around x=0.22 in La 2-x Sr x Cu 1-y M y O 4 ( M = Zn , Ga), suggesting a possibility that an order of holes and/or spins is formed or fluctuates in these samples in the overdoped region.

ALPHA DECAY AND FISSION OF ALIGNED NUCLEI

1960 ◽  
Vol 38 (2) ◽  
pp. 290-314 ◽  
Author(s):  
N. R. Steenberg ◽  
R. C. Sharma
Keyword(s):  
Angular Distribution ◽  
High Temperature ◽  
Experimental Work ◽  
Low Temperatures ◽  
Alpha Decay ◽  
Alpha Particles ◽  
Nuclear Shape ◽  
Fission Fragments ◽  
Partial Waves ◽  
High Temperature Approximation

The theory of the angular distribution of alpha particles and of fission fragments from nuclei aligned at low temperatures is presented. Very explicit results are obtained in the high temperature approximation. These are directly dependent upon the branching which takes place to the various allowed partial waves. This branching is influenced by the nuclear shape, but it is shown that for this problem the effect of penetrating a spheroidal barrier is not critical. An application is made to the experimental work so far available and the result is reasonably satisfactory.

scholarly journals Impact of cryopreservation on lipid composition of reproductive cells of male sterlets (Acipenser Ruthenus L.)

2018 ◽  
Vol 5 (1) ◽  
pp. 73-83
Author(s):  
L. Drahan ◽  
S. Veselsky ◽  
Yu. Rud ◽  
L. Buchatsky
Keyword(s):  
Lipid Composition ◽  
Low Temperatures ◽  
Neutral Lipids ◽  
Sperm Quality ◽  
Phospholipid Bilayer ◽  
Standard Equipment ◽  
Slowing Down ◽  
Acipenser Ruthenus ◽  
Adaptive Property ◽  
The Impact

Aim. To estimate the impact of low temperatures on the lipid composition of reproductive cells of male sterlets (Acipenser ruthenus L) in cryopreservation environment. Methods. The determination of sperm quality (color, consistence, concentration and motility of spermatozoa) was estimated by common biochemical methods using standard equipment. Thin-layer chromatography was used to reveal fi ve fractions of neutral lipids in the sperm of investigated fi sh, which were distributed on the plates as follows: the starting line demonstrated phospholipids, cholesterol, free fatty acids, triacylglycerol and ethers of cholesterol. The adaptive property of sperm was estimated by the level of spermatozoa survival prior to and after cryopreservation. Results. The obtained results of sterlet sperm activity prior to and after cryopreservation demonstrate high quality of native sperm and its considerable deterioration after freezing/thawing. Conclusions. The impact of low temperatures on the lipid composition of reproductive cells of male sterlets (Acipenser ruthenus L) in cryopreservation environment leads to impairments of the phospholipid bilayer of their membranes. It was established that during the thawing of frozen sperm cells which preserved their viability after cryopreservation their motility and capability of fertilizing an ovum were somewhat restored with slowing down of sperm cell motility.

Taxonomic studies on Archigetes Leuckart, 1878 (Cestoda: Caryophyllaeidae)

Parasitology ◽  
1965 ◽  
Vol 55 (3) ◽  
pp. 439-451 ◽  
Author(s):  
C. R. Keneedy
Keyword(s):  
Life History ◽  
Experimental Work ◽  
Nature Conservancy ◽  
The Family ◽  
Single Genus ◽  
Biological Characters ◽  
Taxonomic Studies ◽  
Relationship Of ◽  
Recent Experimental Work ◽  
The Relationship

Recent experimental work has indicated that species of Archigetes are capable of infecting and maturing in fishes in addition to tubificids.The genus Archigetes is re-defined on the basis of morphological and biological characters, with particular emphasis on recent life history studies. All species capable of neotenic development have been re-united in a single genus.A description of all species of Archigetes together with a key for their identification are included. New synonomies are discussed.The relationship of Archigetes to other genera of the family is briefly considered, and it is concluded that it forms the terminal stage in a series showing the attainment of neotenic development.I wish to thank Professor R. J. Pumphrey in whose Department the work was carried out, and Dr J. C. Chubb for advice and help in the preparation of this manuscript. I am also grateful to Professor K. Berg and Dr R. L. Calentine for the loan of specimens. The work was carried out during the tenure of a Nature Conservancy Research Studentship.

Acceptability ratings cannot be taken at face value

2020 ◽  
pp. 189-214
Author(s):  
Carson T. Schütze
Keyword(s):  
Rate Of Convergence ◽  
Experimental Work ◽  
Rates Of Convergence ◽  
Original Method ◽  
Journal Articles ◽  
True Rate ◽  
Acceptability Judgments ◽  
Critical Words ◽  
Recent Experimental Work

This chapter addresses how linguists’ empirical (syntactic) claims should be tested with non-linguists. Recent experimental work attempts to measure rates of convergence between data presented in journal articles and the results of large surveys. Three follow-up experiments to one such study are presented. It is argued that the original method may underestimate the true rate of convergence because it leaves considerable room for naïve subjects to give ratings that do not reflect their true acceptability judgments of the relevant structures. To understand what can go wrong, the experiments were conducted in two parts. The first part had visually presented sentences rated on a computer, replicating previous work. The second part was an interview where the experimenter asked the participants about the ratings they gave to particular items, in order to determine what interpretation or parse they had assigned, whether they had missed any critical words, and so on.

Critical slowing down of spin fluctuations in BiFeO3

2008 ◽  
Vol 20 (42) ◽  
pp. 425223 ◽  
Author(s):  
J F Scott ◽  
M K Singh ◽  
R S Katiyar
Keyword(s):  
Spin Fluctuations ◽  
Critical Slowing Down ◽  
Slowing Down

scholarly journals ROTATIONAL TUNNELLING SPECTROSCOPY WITH NEUTRONS

1993 ◽  
Vol 07 (16n17) ◽  
pp. 3113-3151 ◽  
Author(s):  
C.J. CARLILE ◽  
M. PRAGER
Keyword(s):  
Experimental Work ◽  
Point Of View ◽  
Theoretical Point ◽  
Instrument Performance ◽  
New Approaches ◽  
Recent Experimental Work ◽  
Fruitful Field

Neutron tunnelling spectroscopy has been a very fruitful field for almost two decades and is still expanding into new areas, both experimentally and theoretically. The development of the topic is reviewed from the theoretical point of view, highlighting new approaches, and selected examples of more recent experimental work are presented. A brief discussion of instrument performance and experimental requirements is given.

Numerical Prediction of Various Cavitation Erosion Mechanisms

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Ignacijo Biluš ◽  
Marko Hočevar ◽  
Matevž Dular ◽  
Luka Lešnik
Keyword(s):  
Experimental Work ◽  
High Speed ◽  
Cavitation Erosion ◽  
Cavitating Flow ◽  
Numerical Prediction ◽  
Quantitative Prediction ◽  
Navier Stokes ◽  
Erosion Mechanisms ◽  
Recent Experimental Work ◽  
Collapse Phase

Abstract Numerical prediction of cavitation erosion is a great scientific and technological challenge. In the past, many attempts were made—many successful. One of the issues when a comparison between a simulation and erosion experiments is made, is the great difference in time scale. In this work, we do not attempt to obtain quantitatively accurate predictions of erosion process but concentrate qualitatively on cavitation mechanisms with quantitative prediction of pressure pulses which lead to erosion. This is possible, because of our recent experimental work on simultaneous observation of cavitating flow and cavitation erosion by high speed cameras. In this study, the numerical simulation was used to predict details of the cavitation process during the vapor collapse phase. The fully compressible, cavitating flow simulations were performed to resolve the formation of the pressure waves at cavitation collapse. We tried to visualize the mechanisms and dynamics of vapor structures during collapse phase at the Venturi geometry. The obtained results show that unsteady Reynolds-averaged Navier–Stokes (URANS) simulation of cavitation is capable of reproducing four out of five mechanisms of cavitation erosion, found during experimental work.

Low-temperature Properties of U2Co2InH1.9

2007 ◽  
Vol 62 (7) ◽  
pp. 977-981 ◽  
Author(s):  
Ladislav Havela ◽  
Khrystyna Miliyanchuk ◽  
Laura C. J. Pereira ◽  
Eva Šantavá
Keyword(s):  
High Pressure ◽  
Magnetic Susceptibility ◽  
Specific Heat ◽  
Low Temperatures ◽  
Magnetic Order ◽  
Parent Compound ◽  
Spin Fluctuations ◽  
High Magnetic Fields ◽  
Electronic Specific Heat ◽  
Metamagnetic Transition

Abstract U2Co2InH1.9, synthesized by high-pressure hydrogenation of U2Co2In, crystallizes in the tetragonal structure similar to the parent compound, expanded by 8.4 %. Although U2Co2In is a weak paramagnet, its hydride shows properties suggesting a proximity to the magnetic order. Its magnetic susceptibility exhibits a maximum at T = 2.4 K, ascribed to spin fluctuations. Magnetization at low temperatures goes through a metamagnetic transition between 2 - 3 T. The specific heat characteristics, with a pronounced upturn of Cp/T vs. T at low temperatures which can be fitted using an additional −T 1/2 term, resemble the behaviour of U2Co2Sn. The γ coefficient of the electronic specific heat, reaching 244 mJ mol−1 K−2, is gradually suppressed by high magnetic fields.

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