381,400 research outputs found
Muslim Tionghoa : Cheng Ho
No full textBuku ini membahas catatan perjalanan muhibah Cheng Ho untuk bahan kajian ataupun renungan bagi generasi yang akan datang bahwa pada abad ke-14 telah ada seorang bahariwan asal tiongkok yang telah berlayar ke Asia Afrika.Buku ini terdiri dari Bagian:1. Mengembalikan sejarah yang tenggelam2. Cheng Ho di Indonesia - Apa dan Siapa3. Apa dan siapa Cheng Ho dalam Sejarah Indonesia4. Menggali sejarah Cheng Ho di Indonesia5. Cheng Ho dan Sejarah Indonesiaxiiv, 299 hlm.: ilus.; 22 c
Validity of the Novel Taiwan Lymphoscintigraphy Staging and Correlation of Cheng Lymphedema Grading for Unilateral Extremity Lymphedema
No full textOBJECTIVE: The aim was to validate the new Taiwan Lymphoscintigraphy Staging, correlate it with Cheng Lymphedema Grading (CLG) and evaluate the treatment outcomes of unilateral extremity lymphedema. BACKGROUND: No consensus has been reached for diagnosis and staging for patients with lymphedema among medical specialties. METHODS: We included 285 patients with unilateral extremity lymphedema using lymphoscintigraphy. Lymphoscintigraphy was correlated to clinical symptoms and signs, and classified into normal lymphatic drainage, partial obstruction, and total obstruction. Inter- and intraobserver reliability of Taiwan Lymphoscintigraphy Staging, correlation between Taiwan Lymphoscintigraphy Staging and clinical findings were conducted. Patients were categorized in "surgical" (n = 154) or "nonsurgical" (n = 131) groups for outcome evaluation. RESULTS: Lymphoscintigraphy found 11 patients (3.9%) with normal lymphatic drainage, 128 (44.9%) with partial obstruction, and 146 (51.2%) with total obstruction. Taiwan Lymphoscintigraphy Staging showed high interobserver agreement [intraclass correlation coefficient: 0.89 (95% confidence interval, 0.82-0.94)], and significantly correlated to computed tomography volumetric difference (r = 0.66, P < 0.001) and CLG [intraclass correlation coefficient: 0.79 (95% confidence interval 0.72-0.84)]. At a mean follow-up of 31.2 ± 2.9 months, significant improvement in the circumferential difference (from 23.9% ± 17.6% to 14.6% ± 11.1%; P = 0.03) with a mean circumferential reduction rate of 40.4% ± 4.5% was found in surgical group. At a mean follow-up of 26.6 ± 8.7 months, the nonsurgical group had increase of mean circumferential difference from 24.0% ± 17.2% to 25.3% ± 19.0% (P = 0.09), with a mean circumferential reduction rate was -1.9% ± 13.0%. CONCLUSIONS: The Taiwan Lymphoscintigraphy Staging is a reliable diagnostic tool, correlated with clinical findings and CLG, aiding in the selection of the appropriate treatment to achieve favorable long-term outcomes in unilateral extremity lymphedema
Crack Models For A Transversely Anisotropic Medium
Full text linkA commonly used model for a transversely anisotropic crack rock is that by Hudson
(1980, 1981). This model is based on a simplified analysis of a thin circular crack, with
displacement and stress conditions specified on the boundary. These papers have a
second order correction in addition to the first order term in porosity/crack density. In
this paper we compare the results of Hudson with those of Anderson et al. (1974) and
Cheng (1978) using the long wavelength static approximation and the ellipsoidal crack
model first proposed by Eshelby (1957). We showed that the Hudson model and those
based on the complete Eshelby theory agree for small aspect ratio cracks and small
crack densities, as expected, provided the weak inclusion version of Hudson's model
(1981) is used. For larger crack densities but small aspect ratios, Hudson's first order
term agrees with the Eshelby solution. The expansion in the second order term in crack
density is an asymptotic series and not a uniformly converging series. Thus there is no
general statement one can make about the accuracy of the second order expansion that
is valid for a variety of situations. A new expansion based on the Pade approximation is
proposed which is identical to Hudson's expansion up to second order in density. This
expansion avoids some of the problems associated with Hudson's second order expansion
such as increasing moduli with crack density at relatively small crack densities.Massachusetts Institute of Technology. Borehole Acoustics and Logging ConsortiumUnited States. Dept. of Energy (Grant DE-FG0286ER13636
Laksamana Cheng Ho (kedatangan ke Nusantara dan pengaruhnya terhadap diplomatik Cina-Nusantara tahun 1405-1433)
No full textSkripsi ini menunjukkan bahwa kedatangan Cheng Ho ke Nusantara merupakan misi diplomatik yang diembannya dari Kekaisaran Ming. Dalam rentang waktu kurang lebih 27 tahun, Cheng Ho melakukan tujuh kali pelayaran ke Nusantara dengan armada yang besar. Kedatangan yang membawa misi diplomatik turut berimbas pada hubungan perniagaan dan kebudayaan Nusantara waktu itu.x, 66 hlm.; 29 c
Clean to dirty limit and<i>T</i><sub>c</sub>suppression in NdFeAsO<sub>0.7</sub>F<sub>0.3</sub>studied by<i>H</i><sub>c2</sub>analysis
No full textIn this work, we investigate the temperature dependence of the upper critical field, dH c2/dT, in an increasingly disordered NdFeAsO0.7F0.3 (NdFeAs(O,F)) single crystal that has been progressively irradiated up to a 5.25 ×1016 cm- 2 total particle dose. For the H||ab-plane, dH c2/dT does not vary remarkably with irradiation, while for the H||c-axis it increases sharply after the first irradiation of 3.60 ×1015 cm-2 and then more gradually with further irradiation doses. Focusing on the H||c-axis, we develop a phenomenological analysis of the H c2 slope which allows us to inspect the crossover from the clean to the dirty regime. From the H c2 slope normalized to the critical temperature and to its clean limit value, we extract the ratio of the coherence length ξ BCS to the mean free path and we find that when T c is reduced by a factor of four from its pristine value, ξ BCS/ becomes as large as ∼7 and reaches values of ∼1.8 nm, indicating that NdFeAs(O,F) is well into the dirty regime. Our analysis of the H c2 slope also allows us to compare the pair-breaking effectiveness of scattering in different superconductors, showing similarity between unconventional NdFeAs(O,F) and moderate-T c phonon-mediated devices, such as MgB2 and A15 compounds, but much a stronger difference with YBa2Cu3O7-δ. This work thus shows that dH c2/dT is a reliable parameter, providing an alternative to residual resistivity, for investigating the pair-breaking mechanism induced by impurity scattering in superconductors
The last deglaciation in Italy: timing and pattern from a precisely dated stalagmite
No full textThe last deglaciation (Termination I, T-I) was the most recent global-scale climate transition. It involved a drastic temperature increase guiding massive melting of ice sheets, with a concurrent reorganization of inter- and intrahemispherical atmospheric and ocean circulation patterns.
T-I lasted ~3.0 ka (ka = kiloyears before present) in Greenland (NGRIP, 2007), although it was not a linear process. A rapid temperature increase at 14.6±0.3 ka (Bølling-Allerød, BA) was followed by a return towards glacial-like conditions (12.2±0.3 ka, Younger Dryas, YD), before the last warming that led to the Holocene (11.7±0.1 ka). Other secondary climate oscillations characterized T-I too (Cheng et al., 2020). Some of these intra-deglaciation global warmings were particularly rapid, at times occurring at centennial or even decadal timescale. This provides an interesting comparison with the current climate change.
Yet, it is not clear how T-I-related dynamics occurring at the polar regions and/or in the oceans impacted terrestrial environment at mid latitudes, in terms of rainfall and temperature variation and related environmental and ecological changes. This is especially true for the Mediterranean area, considering that its climate is connected – and controlled – by processes occurring in the Atlantic and Arctic. In Italy, T-I records of adequate chronological resolution are virtually absent.
We here present a novel speleothem record from Sant’Angelo Cave (SA1, Ostuni, Apulia) spanning from 47.7±0.1 to 8.9±0.9 ka. In the period from ~20 to ~10 ka, multiple U-Th datings (n=22) resulted in a final age model with an average uncertainty of <0.3 ka and a resolution of ~25 years. Climate proxies (δ18O, n=1045) were anchored to this chronology. The reliability of SA1-δ18O in recording palaeoclimate information was ascertained by a statistically grounded inter-cave replication test with a recently published speleothem record from a nearby site (Columbu et al., 2020). The interpretation of SA1 allows to: 1) accurately and precisely constrain, for the first time in Italy, the timing of the T-I climate pattern; 2) evaluate the impact of BA, YD and Holocene inception in southern Italy, as well as other associated events, especially in terms of rainfall variability; and 3) understand the spatio-temporal relation between the Atlantic/Greenland domain, the Mediterranean realm and monsoonal areas throughout the deglaciation. We discuss this new record within the framework of previous regional studies based on glacial (NGRIP, 2007), marine (Martrat et al., 2007) and continental proxies (Allen et al., 1999; Cheng et al., 2016), with the aim of providing a better comprehension of the timing and structure of T-I in Italy and, by extension, of the central and western Mediterranean area.
Allen J.R.M., Brandt U., Brauer A., Hubbertens H.W., Huntley B., Keller J., Kraml M., Meckeen A., Mingram J., Negendank J.F.W., Nowaczyk N.R., Oberhansli H., Watts W.A., Wulf S. & Zolitschka B. (1999) - Rapid environmental changes in southern Europe during the last glacial period. Science, 400, 740-743.
Cheng H., Edwards R.L., Sinha A., Spötl C., Yi L., Chen S., Kelly M., Kathayat G., Wang X. & Li X. (2016) - The Asian monsoon over the past 640,000 years and ice age terminations. Nature, 534, 640.
Cheng H., Zhang H., Spötl C., Baker J., et al. (2020) - Timing and structure of the Younger Dryas event and its underlying climate dynamics. Proceedings of the National Academy of Sciences, 117, 23408-23417.
Columbu A., Chiarini V., Spötl C., Benazzi S., Hellstrom J., Cheng H. & De Waele J. (2020) - Speleothem record attests to stable environmental conditions during Neanderthal-Modern Human turnover in Southern Italy. Nature Ecology & Evolution, 4, 1188-1195.
Martrat B., Grimalt J.O., Shackleton N.J., de Abreu L., Hutterli M.A. & Stocker T.F. (2007) - Four climate cycles of recurring deep and surface water destabilizations on the Iberian margin. Science, 317, 502-507.
NGRIP, North Greenland Ice Core Project Members. (2004) - High-resolution record of Northern Hemisphere climate extending into the last interglacial period. Nature, 431, 147-151
The Effects of Confining Pressure and Fluid Saturation on Ultrasonic Velocities in Rocks
Full text linkLaboratory measurements of ultrasonic p- and S-wave velocities were made as
a function of confining pressure for vacuum dry, benzene-, and water-saturated
samples of Westerly granite, Bedford limestone, and Weber, Navajo, Berea, and
Kayenta sandstones. The measurements indicate: 1) water-saturated bulk moduli are
higher than benzene-saturated values, 2) fluid-saturated shear moduli are always
greater than or equal to dry values, and 3) water-saturated shear moduli for the
sandstones are higher than benzene values at low pressure while lower than both
benzene and dry values at higher pressure, Indicating that an apparent water-softening
effect Is concentrated In the shear modulus. Modelling of the velocity
measurements with the Blot (1956a) and Gassmann (1951) equations for static
effective bulk modulus indicates that it underestimates the increase in bulk modulus
and velocities caused by fluid saturation. Inertial effects of the pore fluid as treated
by Blot (1956a, 1956b) are also shown to give minimal improvement to predicted
velocities, which are underestimated. Velocity measurements are modelled with the
Cheng-Kuster-Toksoz ellipsoidal pore and crack model using the inversion technique
developed by Cheng (1978). Fits of dry and benzene-saturated velocities are shown
along with pore aspect ratio distributions at zero pressure. Water-saturated velocity
data and measured porosity reductions with pressure are compared with predictions
of the model
This is the second year we have combined the work of the Logging and Reservoir Delineation groups at the Earth Resources Laboratory. In the first part of this report,
we present work related to logging and petrophysics, including the ongoing work of
electroseismics. This summary describes briefly the contributions of each paper in this
group.
Most of our focus in logging the past year was in understanding the physics of
dipole logging in an azimuthally anisotropic medium, and the processing algorithms
used in characterizing such a medium. In Nolte and Cheng (Paper 2), we analyzed a
cross-dipole data set in extreme detail. We found that the Alford-type rotation appears
to be stable in the anisotropic region of the data. The extra degree of freedom
we used by allowing the principal axes to be nonorthogonal did not affect the results
significantly. Furthermore, the rotation angles are consistent for all seven independently rotated source-receiver pairs. Velocities, on the other hand, are another matter. We used both the semblance method and the homomorphic method to estimate the fast
and slow shear wave velocities from the rotated traces, and compared our results with
those provided by the contractor. We also obtained estimates of velocity anisotropy
from cross-correlation of the principal traces after the rotation. Although all of the processing shows similar variations in the velocities over our interval of interest, the actual velocities varied more than 10 percent. This is probably the result of the large dispersion of the flexural waves. More analysis is necessary to determine the most robust method of obtaining the shear wave velocities.
Paper 3 (Zhu et al.) deals with laboratory dipole logging measurements in a rock
sample with both fast and slow shear wave velocities higher than the acoustic velocity of
water. The authors show evidence of a Stoneley wave that may be coupled to the flexural
waves. Since we really do not have a well-understood theory for such a condition, more work needs to be done to see if any new information can be obtained from this "flexural
Stoneley" mode.
In an area where we have a better understanding of the underlying theory, Tao
and Cheng (Paper 4) investigated the effects of gas-saturation, lithology, and borehole
environment in the determination of permeability from Stoneley waves. This work combined
the previous work in our group of Xiao-Ming Tang, Xiaomin Zhao, and Kazuhiko
Tezuka, among others. The results indicated that small amounts of gas can significantly
affect Stoneley wave dispersion and attenuation. Moreover, in a gas-saturated reservoir,
the Stoneley wave sensitivity to permeability is increased significantly, so that permeability as low as a few millidarcies can be detected effectively. The vertical extent of the permeable zone (as opposed to a fracture) needs to be around 0.5 meters for effective detection.
Tadeu et al. (Paper 5) deals with the numerical modeling of full waveform and
dipole logs using mode summation techniques. Their method is capable of modeling
tool ex-centering and other geometrical effects.
The next series of papers (Zhu and Toksiiz, Paper 6; Mikhailov et al., Paper 7; and
Haartsen and Toksiiz, Paper 8), investigate the electroseismic phenomenon in detail,
using theory, numerical modeling, laboratory scale modeling, and field experiments.
The results demonstrate that the electroseismic effect is indeed real and observable in
the field. This topic is still in the initial stages of development and we will continue the development of the electroseismic technique as a practical tool for detecting fluid flow
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