179 research outputs found
Analytical simulation on experimental seismic response of headed anchors embedded in reinforced concrete
This paper deal with a series of dynamic response analyses, carried out to give numerical correlation of hysteretic behavior of cast-in-place anchorages obtained by the static loading and shake table tests. Specimens for the analyses are reinforced concrete rectangular blocks with embedded headed anchors. Failure modes expected are the steel bolt failure and the concrete cone failure, associated with the respective embedment depth. Initial flexural cracks presumed seismic damage on the concrete block is developed with bending loading. In the analytical model, nonlinear hysteretic behavior of the anchorage is idealized by translational and rotational springs in which properties estimated from the hysteretic loops of the static loading tests. It was shown that the overall force and displacement performance under dynamic loads are well simulated based on the analytical models presented herein
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Deterioration of gallium arsenide diodes
Changes in the diode characteristics of three different
types of diodes were studied. These were point-contact, bonded and zinc-diffused diodes. The parameters
in which measurable changes were observed were the forward
resistance, the reverse breakdown voltage, the
forward "knee" of the diode curve and the constant of
proportionality relating the reverse-bias capacitance to
voltage. Of the three diodes tested, the bonded diodes,
appeared to be the most stable.
The forward resistance increased with time under
load conditions for all types of diodes. In the zinc-diffused diodes large initial changes were observed,
similar to those observed by Shibata. (19) The final
rates of deterioration for all three diodes were about
the same. This suggests that the mechanism of deterioration
in this portion of the curves may be the same for
all three types of diodes. For the final portions of the deterioration curves
of the diffused diodes, the absolute value of load current
is related to changes in resistance by Δ R = K √tI where K is a constant. Difficulty in determining the
actual cross sectional area of the diodes prevented
relating these changes to current density.
In the worst case the proportionality constant
relating voltage to reverse -bias capacitance varied from v⁻¹/².³ to v⁻/³.⁷ for diffused diodes. This indicates
that the type of junction changed from a step to a PIN type.
The voltage at the forward "knee" of the diode
curve increased for the bonded diodes while it decreased
for the point-contact and the diffused diodes. An
increase in junction barrier height may be responsible
for the variation in the bonded diodes while an increase
in surface recombination states may be responsible for
the decrease in the point-contact case. The spreading
of the pn junction by diffusion of an electrically
active element is a possible cause of the change in
diffused diodes
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Properties of flash-evaporated gallium arsenide and gallium phosphide epitaxial films
The properties of flash- evaporated films of GaAs
and GaP were studied in this investigation. Films were
grown at various substrate temperatures, source temperatures,
source-to-substrate distances and rates of deposition
and were evaluated as to their structural,
optical and electric properties.
It was found that substrate temperature was the
major factor in determining the crystallinity of the
films. Films deposited below about 250°C were found to
be amorphous. As the substrate temperature was increased,
the crystallinity of the films improved.
The optical data showed that the films had band
gaps in the range of 1.34 to 1.72 ev. for GaAs films.
Temperature-versus-resistivity measurements showed that
the band gap for GaAs films varied from 1.18 ev. to
1.72 ev. The value for bulk GaAs is 1.47 ev. Films grown from evaporant powders obtained by
crushing wafers of 6x10⁻³ ohm-cm to 0.01 ohm-cm material
had very high resistivities. To lower film resistivity,
additional doping was incorporated in the evaporant.
Tin was added to n-type wafers and zinc to p-type wafers.
The films grown from the tin-rich evaporant powders
showed a decrease in resistivity for an increase in tin
concentration and an increase in resistivity for a decrease
in substrate temperature. Films grown from zinc-rich powders had high resistivities in all cases.
Hall measurements were made but most films showed
no voltage above the noise level of the measuring apparatus.
The highest mobility value calculated from those
films that exhibited Hall voltage was 0.7 cm²/volt-sec,
far below the value of 8500 cm²/volt-sec for bulk GaAs.
Electroluminescence was noted in high-resistivity
GaP films grown on GaAs substrates. A wide spectral
emission energy band was measured which would indicate
an avalanche process as being the carrier injection
mechanism.
Point- contact and evaporated diodes were fabricated
from the flash-evaporated films. Large leakage currents
were noted in both types of diodes
Electrochemical Synthesis of Thienoacene Derivatives: Transition‐Metal‐Free Dehydrogenative C−S Coupling Promoted by a Halogen Mediator
The first electrochemical dehydrogenative C−S bond formation leading to thienoacene derivatives is described. Several thienoacene derivatives were synthesized by dehydrogenative C−H/S−H coupling. The addition of nBu4NBr, which catalytically promoted the reaction as a halogen mediator, was essential
An Empirical Study of the Factors Contributing to Japanese Junior High School Students' Listening Ability in English
The aim of the present paper is to ascertain the relationship between the listening skill and the other language (sub) skills of Japanese EFL learners at the junior high school level. The study of listening skill in second/ foreign language learning has traditionally focused on the roles of individual linguistic units, e.g. phonemes, words, grammatical structures and in the belief that the development of those elements would eventually lead to the enhancement of the overall listening skill, teaching listening comprehension has been considered the training of these linguistic units. Recently, however, the roles of the listener's background world knowledge, expectations, the situation and context have been brought to the attention of Second/ Foreign Language (SL/FL hereafter) research and it was found that a lack of subordinate skills can be compensated by the learner's world knowledge. In other words, greater importance has been attached to the multiple perspectives in building up the listening ability. However, behind these single skill acquisition studies, little attention has been paid to a multiple relationship between different language skills; for instance, between listening and speaking. How is the development of listening skill related to other language skills such as speaking or reading? Furthermore, most SL/FL studies are targeted to adolescent or adult SL/FL learners; in contrast, very few studies of this kind have been carried out in the initial stage of SL/FL learning, that is, at the junior high school level. Therefore, using a statistical procedure, the present authors tried to identify some variables, language skills and linguistic factors, which are more likely to influence the development of listening skill at an early stage of SL/FL learning
Big Three Dragons: A [N II] 122 m Constraint and New Dust-continuum Detection of A Bright Lyman Break Galaxy with ALMA
We present new Atacama Large Millimeter/submillimeter Array Band 7
observational results of a Lyman break galaxy at , B14-65666 ("Big
Three Dragons"), which is an object detected in [OIII] 88 , [CII]
158 , and dust-continuum emission during the epoch of reionization.
Our targets are the [NII] 122 fine-structure emission line and
underlying 120 dust continuum. The dust continuum is detected with
a 19 significance. From far-infrared spectral energy
distribution sampled at 90, 120, and 160 , we obtaine a best-fit
dust temperature of K ( K) and an infrared luminosity of () at the emissivity index (1.0). The [NII] 122 line is not detected. The 3 upper limit of the [NII] luminosity is . From the [NII], [OIII], and [CII] line luminosities, we use the
Cloudy photoionization code to estimate nebular parameters as functions of
metallicity. If the metallicity of the galaxy is high (), the ionization parameter and hydrogen density are and -,
respectively, which are comparable to those measured in low-redshift galaxies.
The nitrogen-to-oxygen abundance ratio, , is constrained to be
sub-solar. At , the allowed drastically
increases as the assumed metallicity decreases. For high ionization parameters,
the constraint becomes weak. Finally, our Cloudy models predict the
location of B14-65666 on the BPT diagram, thereby allowing a comparison with
low-redshift galaxies.Comment: 17 pages, 13 figures, 2 tables. accepted for publication in Ap
Practice for the Development of 21st-Century Academic Achievement by Subject between Cooperation in Junior High School : Through the Global Educational Exchange by Means of English and Art
本研究は中学校の英語科・美術科の教科担任がグローバル教育の意識を持って,単元・題材を接続させ,連続性のある指導をすることにより,生徒に習得した知識・技能を地域社会へ向けた実践に活用させ,21世紀型学力へ通じる通教科的な実践力の育成の在り方を明らかにすることを目的とする。広島大学附属三原中学校の1,2年生を対象に授業実践を行い,外部評価者としてアメリカのアートリンク担当者やショートステイ家族に協力を依頼した。結果としては,生徒たちは美術作品を描いたり,鑑賞したりすることによって,気づいたよさや美しさを外国の方に伝える方法を考えて実践している様子が見られた。The aim of this study was to improve students’ communication skills. We worked with English teachers and art teachers to develop a curriculum through practice force leading to 21st century academic achievement. We targeted the teaching practice to grades seven and eight in Mihara Junior High School in Japan, and cooperated with both the Art Link in America and short-stay family as external evaluators. As a result, the students could express their impressions to people in foreign countries
Helicobacter pylori from gastric cancer and duodenal ulcer show same phylogeographic origin in the Andean Region in Colombia
Background: A recent report has shown that the phylogenetic origin of Helicobacter pylori based on multi-locus sequence typing (MLST) was significantly associated with the severity of gastritis in Colombia. However, the potential relationship between phylogenetic origin and clinical outcomes was not examined in that study. If the phylogenetic origin rather than virulence factors were truly associated with clinical outcomes, identifying a population at high risk for gastric cancer in Colombia would be relatively straightforward. In this study, we examined the phylogenetic origins of strains from gastric cancer and duodenal ulcer patients living in Bogota, Colombia. Methods: We included 35 gastric cancer patients and 31 duodenal ulcer patients, which are considered the variant outcomes. The genotypes of cagA and vacA were determined by polymerase chain reaction. The genealogy of these Colombian strains was analyzed by MLST. Bacterial population structure was analyzed using STRUCTURE software. Results: H. pylori strains from gastric cancer and duodenal ulcer patients were scattered in the phylogenetic tree; thus, we did not detect any difference in phylogenetic distribution between gastric cancer and duodenal ulcer strains in the hpEurope group in Colombia. Sixty-six strains, with one exception, were classified as hpEurope irrespective of the cagA and vacA genotypes, and type of disease. STRUCTURE analysis revealed that Colombian hpEurope strains have a phylogenetic connection to Spanish strains. Conclusions: Our study showed that a phylogeographic origin determined by MLST was insufficient for distinguishing between gastric cancer and duodenal ulcer risk among hpEurope strains in the Andean region in Colombia. Our analysis also suggests that hpEurope strains in Colombia were primarily introduced by Spanish immigrants. © 2014 Shiota et al
Pancreatic Pseudocysts - Proposal for Diagnosis and Surgical Management -
To determine the clinical features and problems presented by a pancreatic pseudocyst, eighteen patients managed at our hospitals since 1980 were reviewed. Males predominated with a ratio of 16: 2, and the average age was 36.2 years. Pseudocyst was located in the pancreatic head in 6, in the body in 6, in the tail in 5 and multiple pseudocysts in one case. The cause of pancreatic pseudocyst was chronic pancreatitis in 9 (including 8 patients with histories of alcoholism), acute pancreatitis in 2 and trauma in 7 patients, respectively. Three patients were associated with pancreatic calculi. Rupture of pseudocyst occurred in one patient with multiple cysts. Autopsy showed acute pancreatic necrosis and penetration to the stomach and duodenum. The indications for surgery were principally cyst-related symptoms(infection, hemorrhage, enlargement and compression of adjacent organs) and differential diagnosis from malignancy. Most of the patients underwent internal drainage ; 9 cystojejunostomy, 2 cystogastrostomy). Three patients underwent cystojejunostomy with longitudinal pancreaticojejunostomy for chronic pancreatitis. Massive hemorrhage after cystogastrostomy occurred in one patient with infected pseudocysts, which required removal of the cysts. Postoperative outcome of the 17 surgical patients was excellent in 16 patients. Only one patient died of pancreatitis associated with alcohol abuse, resulting in a 5.9% mortality. This study suggests that adequate internal drainage by pancreaticojejunostomy to treat the underlying pancreatic disease is most important to obtain an excellent prognosis in patients with pseudocysts
Large Population of ALMA Galaxies at z>6 with Very High [OIII]88um to [CII]158um Flux Ratios: Evidence of Extremely High Ionization Parameter or PDR Deficit?
We present our new ALMA observations targeting [OIII]88um, [CII]158um,
[NII]122um, and dust continuum emission for three Lyman break galaxies at
z=6.0293-6.2037 identified in the Subaru/Hyper Suprime-Cam survey. We clearly
detect [OIII] and [CII] lines from all of the galaxies at 4.3-11.8sigma levels,
and identify multi-band dust continuum emission in two of the three galaxies,
allowing us to estimate infrared luminosities and dust temperatures
simultaneously. In conjunction with previous ALMA observations for six galaxies
at z>6, we confirm that all the nine z=6-9 galaxies have high [OIII]/[CII]
ratios of L[OIII]/L[CII]~3-20, ~10 times higher than z~0 galaxies. We also find
a positive correlation between the [OIII]/[CII] ratio and the Lya equivalent
width (EW) at the ~90% confidence level. We carefully investigate physical
origins of the high [OIII]/[CII] ratios at z=6-9 using Cloudy, and find that
high density of the interstellar medium, low C/O abundance ratio, and the
cosmic microwave background attenuation are responsible to only a part of the
z=6-9 galaxies. Instead, the observed high [OIII]/[CII] ratios are explained by
10-100 times higher ionization parameters or low photodissociation region (PDR)
covering fractions of 0-10%, both of which are consistent with our [NII]
observations. The latter scenario can be reproduced with a density bounded
nebula with PDR deficit, which would enhance the Lya, Lyman continuum, and C+
ionizing photons escape from galaxies, consistent with the [OIII]/[CII]-Lya EW
correlation we find.Comment: 20 pages, 18 figures, Accepted for publication in Ap
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