Double Peak Type Research Articles

IPTF15dtg: a double-peaked Type Ic supernova from a massive progenitor

Type Ic supernovae (SNe Ic) arise from the core-collapse of H (and He) poor stars, which could be either single WR stars or lower-mass stars stripped of their envelope by a companion. Their light curves are radioactively powered and usually show a fast rise to peak ($\sim$10-15 d), without any early (first few days) emission bumps (with the exception of broad-lined SNe Ic) as sometimes seen for other types of stripped-envelope SNe (e.g., Type IIb SN 1993J and Type Ib SN 2008D). We have studied iPTF15dtg, a spectroscopically normal SN Ic with an early excess in the optical light curves followed by a long ($\sim$30 d) rise to the main peak. It is the first spectroscopically-normal double-peaked SN Ic observed. We aim to determine the properties of this explosion and of its progenitor star. Optical photometry and spectroscopy of iPTF15dtg was obtained with multiple telescopes. The resulting light curves and spectral sequence are analyzed and modelled with hydrodynamical and analytical models, with particular focus on the early emission. Results. iPTF15dtg is a slow rising SN Ic, similar to SN 2011bm. Hydrodynamical modelling of the bolometric properties reveals a large ejecta mass ($\sim$10 $M_{\odot}$) and strong $^{56}$Ni mixing. The luminous early emission can be reproduced if we account for the presence of an extended ($\sim$500 R$_{\odot}$), low-mass ($\sim$0.045 M$_{\odot}$) envelope around the progenitor star. Alternative scenarios for the early peak, such as the interaction with a companion, a shock-breakout (SBO) cooling tail from the progenitor surface, or a magnetar-driven SBO are not favored. The large ejecta mass and the presence of H and He free extended material around the star suggest that the progenitor of iPTF15dtg was a massive ($\gtrsim$ 35 M$_{\odot}$) WR star suffering strong mass loss.

Mean pressure distributions around a circular cylinder in the branch of a T-junction with/without vanes

The mean pressure distributions of a single circular cylinder in the branch of a T-junction with and without vanes are experimentally investigated in a low-speed wind tunnel. Experimental data of the circular cylinder in a straight duct are conducted to provide a benchmark. Mean pressure distributions of the circular cylinder are obtained at different positions along streamwise direction under the velocity ratio (R) ranging from 0.13 to 0.36. The detailed flow structure is observed with the help of numerical simulation validated by available experimental data. Two dimensionless parameters including correlation degree and amplitude ratio, are defined to analyze the pressure characteristics around the circular cylinder. It is found that, both the correlation degrees and the amplitude ratios increase totally with increasing distance of the circular cylinder away from the interface of the T-junction with/without vanes. Moreover, the pressure distributions around the circular cylinder in the T-junction without vanes show a double-peak type especially at a low velocity ratio, and thus present low correlation degrees compared with the benchmark, meanwhile, the amplitude ratios decrease from double to half of the benchmark level. Whereas, the pressure distributions around the circular cylinder in the T-junction with vanes show good agreement with the benchmark at a high velocity ratio. The flow structures obtained from simulation results reveal that the velocity distributions in the T-junction with vanes are more uniform than those without vanes so that the pressure distributions around the circular cylinder are much closer to the benchmark. The results would be helpful for designing the ventilation and heat transfer equipment used in high speed train.

Spin-up/spin-down of neutron star in Be-X-ray binary system GX 304-1

We analyze spin-up/spin-down of the neutron star in Be X-ray binary system GX\,304-1 observed by \textit{Swift}/XRT and \textit{Fermi}/GBM instruments in the period of the source activity from April 2010 to January 2013 and discuss possible mechanisms of angular momentum transfer to/from the neutron star. We argue that the neutron star spin-down at quiescent states of the source with an X-ray luminosity of $L_x\sim 10^{34}$~erg s$^{-1}$ between a series of Type I outbursts and spin-up during the outbursts can be explained by quasi-spherical settling accretion onto the neutron star. The outbursts occur near the neutron star periastron passages where the density is enhanced due to the presence of an equatorial Be-disc tilted to the orbital plane. We also propose an explanation to the counterintuitive smaller spin-up rate observed at higher luminosity in a double-peak Type I outburst due to lower value of the specific angular momentum of matter captured from the quasi-spherical wind from the Be-star by the neutron star moving in an elliptical orbit with eccentricity $e\gtrsim 0.5$.

The Study in Sap Flow Characteristics and Photosynthetic Characteristics of Haloxylon Ammodendron and Tamarix in the Gurbantunggute Desert

According to the sap flow characteristics and photosynthetic characteristics of Haloxylon ammodendron and Tamarix, we measured the sap flow with the method of thermal diffusion. To monitor photosynthesis with application the instrument CI-340, and the result shows that: (1)The daily net photosynthetic rate change of Haloxylon ammodendron is a typical double peak type, and Tamarixs is a single peak type; (2)The daily transpiration variation of Haloxylon ammodendron is similar to net photosynthetic rate change rule, it has a phenomenon which we called noon break, Tamarixs isnt obvious, it presents volatile changes slightly; (3)The daily sap flow of Haloxylon ammodendron is a typical double peak type, Tamarixs isnt obvious, it presents volatile changes slightly, and at sometimes the sap flow of branches is greater than the breasts. The results provide some supports for ecological water demand of the plants. It has some significance for ecological environment construction of the Gurbantunggute Desert.

In situ experiments on supporting load effect of largespan deep tunnels in hard rock

A section of the Nanliang high speed railway tunnel on Shijiazhuang-Taiyuan high-speed passenger railway line in China was instrumented and studied for its mechanical properties and performances. The cross section for the tunnel was 300 m2 and is classified as the largest cross section for railway tunnels in China. Through in situ experimental studies, mechanistic properties of the tunnel were identified, including the surrounding rock pressure, convergences along tunnel perimeter and safety of primary support and lining structure. Based on the field measured data, the surrounding rock pressure demand for large-span deep tunnel in hard rock is recommended as double peak type in the vertical direction and fold line type was recommended for horizontal pressure. The results suggested that Promojiyfakonov’s theory was most close to the monitored value. Specific recommendations were also generated for the use of bolts in tunnel structures. Numerical simulation was used to evaluate the safety of the tunnel and it confirmed that the current design can satisfy the requirement of the current code.

Mechanical properties and texture evolution during hot rolling of AZ31 magnesium alloy

Mechanical properties and texture evolutions of the as-rolled AZ31 Mg sheets were investigated. The results show that the grains of the sheets are significantly refined after hot rolling. The mechanical properties of the as-rolled samples are enhanced due to the grain size refinement. The intensity of basal texture decreases with the increase of deformation ratio, and double-peak type basal texture is discovered in the intermediate and large strain hot rolling processes. The formation of the texture is ascribed to the activities of prismatic and non-basal < c+ a> slips, which is the same as the 30% rolled and 50% rolled samples. The incline of basal planes exerts an effect on the mechanical anisotropy during tension along rolling direction (RD) and transverse direction (TD) at room temperature.

Microstructure and mechanical properties of Mg–Al–Zn alloy sheet fabricated by cold extrusion

Cold extrusion of AZ31 magnesium alloy sheets was studied in this paper. Microstructure and texture distributions of the as-extruded sheet were investigated by electron backscattered diffraction (EBSD) method. The grains were significantly refined and the average grain size was 1.6 μm. Dynamic recrystallization has taken place during the extrusion process, which resulted in the high frequency of high angle grain boundaries in the sheet. After the cold extrusion, a weak double-peak type basal texture was formed. The formation of the texture was ascribed to the non-basal < c + a> slips. Tensile tests revealed that mechanical properties were enhanced due to grain size refinement, but mechanical anisotropy was obvious. It is believed that mechanical anisotropy was related to the splitting of basal texture.

골프 드라이버스윙 시 지면반력 반복측정 횟수와 지면반력 특성

Grould Reaction force(GRF) is important in human movements and GRF measurements are one of the most frequently used tool in biomechanical studies. In the studies of the golf swing motion, people refer to GRF as weight transfer. A successful golf swing motion requires many segments activation sequences which are controled by the nerve system. Due to the inter- and intra-individual variability of the human movement and the movement strategies, reliability of the measurements are important in human movement studies. Previous golf researches were based on group studies and certain events' values were analyzed. The purposes of this study were to determine the number of trials for the reliable golf swing GRF data collection, to reveal the variability level of the meaningful components of the golf swing GRF, and to classify the types of the golf swing GRF patterns. Twenty three male professional golfers(<TEX>$26.4{\pm}6.6$</TEX> years, <TEX>$174.3{\pm}5.2\;cm$</TEX>, <TEX>$71.3{\pm}6.5\;kg$</TEX>) signed an informed consent form prior to participation in this study. GRFs of driver swings were collected with Kistler 9285 force platform and 9865A amplifier, and calculated by the KwonGRF program(Visol, Korea). Sampling frequency was 1080 Hz. GRF data were trimmed from 1.5 s prior to the impact to 0.5 s after the impact. The number of trials for the reliable GRF collection was determined when the change in floating mean overs the 25 % of the standard deviation of that variable. Variabilities of the variables were determined by the coefficient of variation(CV) of 10 %. The types of GRF patterns were determined by visual inspection of the peak GRF shapes. The minimum number of trials for the reliable golf swing GRF data collection was five. Ten-trial seems more conservative. The value of the peak GRF was more reliable than the value of the impact GRF. The CV of the peak GRF and impact GRF were 7.4 %, 15.2 %, respectively. Because of the +/- sigh of the peak GRF appearance time, it was impossible to calculate CV of the peak GRF appearance time. Golf swing GRF patterns were classified as sing peak type, double peak type, and plateau peak type. This classification suggests the presence of the different golf swing weight transfer strategies.

A 12-Station Anatomic Hip Joint Simulator

A novel 12-station hip joint simulator with an anatomic position of the prosthesis was designed and built. The motion of the simulator consists of flexion-extension and abduction-adduction. The load is of the double-peak type. The validation test was done with three similar 28 mm CoCr-polyethylene joints in diluted calf serum lubricant for 3.3 x 10(6) cycles. The bearing surfaces of the polyethylene cups were burnished, the CoCr heads were undamaged, the wear particles were in the 0.1-1 microm size range, and the mean wear factor of the polyethylene cups was 5.7 x 10(-7) mm(3)/N m. These essential observations were in good agreement with clinical findings. In addition, three similar 50 mm CoCr/CoCr joints, representing the contemporary large-diameter metal-on-metal articulation were tested. The wear of the CoCr/CoCr joints was calculated from the Co and Cr concentrations of the used lubricant quantified with atomic absorption spectroscopy. The bearing surfaces of the CoCr/CoCr joints showed mild criss-cross scratching only. The average wear factor of polyethylene cups was 275 times that of the CoCr/CoCr joints. The tribological behaviour of the large-dia. CoCr/CoCr appeared to be dominated by fluid film lubrication, as indicated by very low frictional heating and wear, making it tribologically superior to the conventional CoCr/polyethylene, and therefore very interesting clinically. In conclusion, the simulator proved to be a valid, reliable, practical, economical, and easy-to-operate tool for wear studies of various hip replacement designs.

Detection of harmonic ultrasound scattered from microbubbles with ultrasound transducer for harmonic imaging having double peak type frequency characteristics

Ultrasound transducer with double peak type frequency characteristics was proposed for contrast harmonic imaging. It can transmit ultrasound in a fundamental mode and receive the second harmonic signal from tissues or microbubble contrast agents. The transducer has been made by stacking a piezoelectric ceramic vibrator and a subvibrating plate on the backing block made of ferrite rubber with an acoustic absorption. Glass subvibrating plate (0.4 mm thick) was found suitable for this ultrasound transducer. The second harmonic component contained in the scattered waves from microbubbles coated with surfactant was detected experimentally with a trial manufactured ultrasound transducer with double peak type frequency characteristics. The results confirmed that the transducer can transmit ultrasound to microbubbles, excite the second harmonic component based on the nonlinear behavior of microbubbles and detect the second harmonic component. It was also found that the second harmonic component can be detected most effectively when burst waves with cycles from 5 to 10 were applied to the ultrasound transducer.

アルミニウム合金管／鋼管摩擦圧接継手の引張強さ特性の統計的解析

In present study, various aluminum alloys pipe to steels pipe were friction welded, and the mean value and scatter of welded joints were investigated. That is, thirty specimens for each combination of three aluminum alloys pipe to five steels pipe were friction welded under the optimum friction welding condition and the joint efficiency of welded joints were evaluated by tensile test. After performing statistical analysis and Weibull analysis on the joint efficiency, the following results were obtained, (1) The joint efficiency of A6061/steel showed a normal type distribution, but the A5052/steel and A6063/steel showed a distortional type and a double peak type distribution, respectively. (2) A difference was found in the joint efficiency of A5052/carbon steel and A5052/stainless steel showing high joint efficiency in the A5052/S45C and A5052/SUS304. (3) In the A606l/carbon steel and A6061/stainless steel, no difference was found in joint efficiency. (4) In the case of A6063/carbon steel, any difference of the joint efficiency was not found, while a difference was found in the case of A6063/stainless steel. (5) A reference table on the joint efficiency and joint strength for three aluminum alloys pipe to five steels pipe was presented.

Morphologies of Hα Accretion Regions in Algol Binaries

We have investigated a group of 18 Algol-type binaries to determine the general morphologies and physical properties of the accretion regions in these systems. The systems studied were V505 Sgr, RZ Cas, AI Dra, TV Cas, TW Cas, δ Lib, RW Tau, TW Dra, β Per, TX UMa, U Sge, S Equ, U CrB, RS Vul, SW Cyg, CX Dra, TT Hya, and AU Mon, in order of increasing orbital period P = 1.18-11.11 days. In addition, the RS CVn-type binary HR 1099 (V711 Tau) was observed to illustrate the appearance of chromospheric Hα emission. Nearly 2200 time-resolved Hα spectra were collected from 1992 March to 1994 December with the McMath-Pierce Solar Telescope at NSO and mostly with the Coude Feed Telescope at KPNO. The spectra were obtained at phases around the entire orbit of each binary and were closely spaced to permit the detection of transitions in the profiles. Moreover, the spectra were obtained typically within three orbital cycles to reduce the influence of secular variations. Difference profiles were calculated by subtracting a composite theoretical photospheric spectrum from the observed spectrum. The analysis of the Hα difference profiles demonstrates that the accretion structures in Algol binaries have four basic morphological types: (1) double-peaked emission systems in which the accretion structure is a transient or classical accretion disk; (2) single-peaked emission systems in which the accreted gas was found along the trajectory of the gas stream and also between the two stars in an accretion annulus; (3) alternating single- and double-peaked emission systems, which can change between a single-peaked and a double-peaked type within an orbital cycle; and (4) weak spectrum systems in which there was little evidence of any accretion structure since the difference spectra are weak at all phases. The first two types are the dominant morphologies. The first type can be interpreted physically as a disklike distribution, while the second is a gas stream-like distribution. The most common type in short-period Algols with 2.7 days 6 days) were found to have slightly variable but permanent accretion disks at all epochs (i.e., CX Dra, TT Hya, and AU Mon), similar to those found in cataclysmic variables. SW Cyg (P = 4.57 days) was found to be an intermediate case between the shorter period systems with P 6 days. Two systems, U Sge and U CrB, displayed alternating single- and double-peaked emission at different epochs (Type 3), and changes from one type to another were detected within a 12 hour time interval. Observations at multiple epochs suggest that four members of the single-peaked emission group, namely RW Tau, TX UMa, S Equ, and RS Vul, may actually belong to the alternating group. So, the complete group of alternating systems covers periods of 2.7 days < P < 4.5 days. Finally, the systems V505 Sgr, δ Lib, AI Dra, TW Cas, and TV Cas had weak difference spectra or uninteresting observed spectra at most phases (Type 4). All of these systems have orbital periods P < 2.4 days and are high in the r-q diagram. In these cases, the mass-gaining star is very large relative to the binary separation, and the path of the gas stream path is very short, so there is very little room to form any substantial accretion structures as found in the other systems.

Evidence of late palaeozoic thermalwater metallization in South Yongmei Depression

This paper discusses the seafloor thermalwater spout sedimentary activity in South Yongmei Depression according to the following evidences: the Yongmei region was in an extended tectonic environment of metaplateform and locally developed intracontinental rift aulacogen in company with the activity of rich alkali, high potassium volcanics of double-peak type. Several kinds of hydrothermal sedimentary rocks and the ore-bearing sedimentary formations of copper-polymetals, iron and manganese exist in this region with a zoning feature of the seafloor thermalwater spout sedimentation.

The effect of pH on both spectral types of R-phycoerythrin

There are two spectral types of R-phycoerythrin (RPE) in red algae. One is the triple peak type RPE with absorption maxima at 498,540 and 565 nm. The other is the double peak type RPE with absorption maxima at 498 and 565 nm, and an absorption shoulder at 540 nm. The former is present only in higher classes of the more advanced Florideophyceae, the latter occurs chiefly in the more primitive Bangiophyceae. When these two types of RPE are treated with buffer solutions with a broad pH range from 2.0 to 11.0, their absorption and fluorescence spectra remain unchanged within the range adjacent to neutral pH. At pH values higher than 9.6, the absorption and fluorescence spectra of triple peak type RPE still remain stable, but the absorption spectra of double peak type RPE produce gradually a protrusion similar to an absorption peak at about 540 nm. This phennomenon shows that there are certain differences in structure between these two types of RPE. Both types of RPE are naturally occurring products showing systematic developmental meaning in red algae.

乳牛の人工授精後における乳汁中Progesterone濃度の変動と受胎との関係 (予報)

Milk progesterone profiles after artificial insemination (AI) were classified into the following four patterns:(1) normal type. Progesterone level (PL) rose promptly and remained high up to 2-3 days prior to estrus or day of pregnancy diagnosis (59%), (2) double peak type. PL rose first, then dropped temporarily in middiestrus, and rose again, forming double peaks (24%), (3) insufficiently rising type. PL rose, but remained below the lower limitof the normal range (11%), and (4) delayed type. PL rose 8-10days after AI (6%).Of 54 cows inseminated fifteen (28%) became pregnant, 29 returned to estrus 19-26days after AI, and ten maintained high PL's up to 30-60days after AI until they came into estrus. These 10 cows were considered to have had embryonic death. All the pregnant cows, but one, were associated with type 1. Of the 29 non-pregnant cows, eleven (38%) showed type 1, another eleven type 2, five (17%) type 3, and two (7%) type 4. Of the last 10 cows, seven (70%) showed type 1.It was suggested that the patterns of milk PL after AI rather than PL's themselves, might be associated with the fertility of cows.