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^(12)CO J=2-1 and^(12)CO J=3-2 observations toward the high-mass protostellar candidate IRAS 20188+3928

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Research in Astronomy and Astrophysics 2013年第1期13卷 39-46页

作者： Jin-Long Xu jun-jie wang National Astronomical Observatories Chinese Academy of Sciences NAOC-TU Joint Center for Astrophysics

We have carried out observations of 12CO J=2-1 and 12CO J=3-2 to- ward the high-mass protostellar candidate IRAS 20188＋3928. Compared with previ- ous observations, the 12CO J=2-1 and 12CO J=3-2 lines both have asymmetric pro- files with an absorption dip. The velocity of the absorption dip is ~ 1.0 km s-1. The spectral shape may be caused by rotation. The velocity-integrated intensity map and position-velocity diagram of the 12CO J=2-1 line present an obvious bipolar com- ponent, further verifying that this region has an outflow motion. This region is also associated with an HII region, an IRAS source, and an H20 maser. The H20 maser has the velocity of 1.1 km s-1. Compared with the components of the outflow, we find that the H20 maser is not associated with the outflow. Using the large velocity gradi- ent model, we concluded that possible averaged gas densities of the blueshifted lobe and redshifted lobe are 1.0x 105 cm-3 and 2.0x 104 cm-a, while kinetic temperatures are 26.9 K and 52.9 K, respectively. Additionally, the outflow has a higher integrated intensity ratio （Ico J=3 - 2/Ico J=2 - 1）.

关键词： ISM: individual (IRAS 20188+3928) -- ISM: kinematics and dynamics-- ISM: molecules -- stars: formation

Star formation associated with the infrared dust bubble N68

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Research in Astronomy and Astrophysics 2013年第1期13卷 47-56页

作者： Chuan-Peng Zhang jun-jie wang National Astronomical Observatories Chinese Academy of Sciences NAOC-TU Joint Center for Astrophysics University of Chinese Academy of Sciences

We investigated the environment of the infrared dust bubble N68 and searched for evidence of triggered star formation in its surroundings. We performed a multiwavelength study of the nebula with data taken from several large-scale surveys： GLIMPSE, MIPSGAL, IRAS, NVSS, GRS and JCMT. We analyzed the spectral pro- file and the distribution of the molecular gas （13CO J -- 1 - 0 and J -- 3 - 2）, and the dust in the environment of N68. The position-velocity diagram clearly shows that N68 may be expanding outward. We used two three-color images of the mid-infrared emis- sion to explore the physical environment, and one color-color diagram to investigate the distribution of young stellar objects （YSOs）. We found that the 24 p^m emission is surrounded by the 8.0 ~m emission. Morphologically, the 1.4 GHz continuum strongly correlates with the 24 gm emission, and the 13CO J -- 1 - 0 and J -- 3 - 2 emissions correlate well with the 8.0 p^m emission. We investigated two compact cores located in the shell of N68. The spectral intensity ratios of 13CO J -- 3 - 2 to J = 1 - 0 range from 5 to 0.3. In addition, YSOs, masers, IRAS and UC HII regions are distributed in the shell of the bubble. The active region may be triggered by the expansion of the bubble N68.

关键词： infrared stars -- stars: formation -- ISM bubbles -- HII regions

Properties of the high-mass star forming region IRAS 22475+5939

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Research in Astronomy and Astrophysics 2012年第7期12卷 845-856页

作者： Xiao-Lan Liu jun-jie wang National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

IRAS 22475＋5939 has been we can still discover new characteristics well studied by previous astronomers, but about it, using the first observations of the lines from CO J=2-1, 13C0 J=2-1 and 13CO J=3-2 by the KOSMA 3m telescope. The mapping of the intensity ratio of 13CO J=3-2 and 13CO J=2-1 shows that the distribution of the temperature has two peaks, neither of which coincide with the IRAS 22475＋5939 source or the center of the HII region, but rather are located at the edge of the HII region. Overlays of the Spitzer IRAC 8 p.m with CO contours indicate that they are associated with each other and that the strongest polycyclic aro- matic hydrocarbon （PAH） emission is at the IRAS 22475＋5939 source position. The IRAS LRS spectrum at 7μm-23 μm and the PHT-s spectrum at 2μm-12μm of the IRAS 22475＋5939 source also exhibit strong PAH emission characteristics in the main PAH bands： The diversity of the PAH family should be responsible for the plateaus in the PAH emission in the PHT-s and IRAS-LRS spectra. Analysis and mod- eling in the infrared bands suggest that IRAS 22475＋5939 is more likely to be a class I young stellar object. Where this is the case, the star is likely to have a tempera- ture of Tefr-9995.8K, mass-15.34Mo, luminosity -1.54×104 L- and age 1.54-104 yr. The model shows that circumstellar disc emission is important for wavelengths between 1 and 10μm, otherwise, the envelope fluctuates for A 〉 10μm. Bipolar outflow is confirmed in the molecular cloud, and the excited star of the HII region could be the driving source of the outflow. High resolution is required fm better results.

关键词： ISM: jets and outflow -- ISM: molecular -- ISM: kinematical and dy-namics -- star formation

Molecular outflows and gas rotation associated with G20.08–0.14N

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Research in Astronomy and Astrophysics 2013年第11期13卷 1295-1306页

作者： Nai-Ping Yu jun-jie wang National Astronomical Observatories Chinese Academy of Sciences NAOC-TU Joint Center for Astrophysics

We present the results of a high-resolution study with the Submillimeter Array （SMA） toward the massive star-forming complex G20.08-0.14N. With the SMA data, we have detected and analyzed the transitions in the 12CO （3-2） and 12CO （2-1） molecular lines as well as CHaCN. The millimeter observations reveal highly collimated bipolar molecular outflows, traced by high-velocity 12CO （2-1） and 12CO （3-2） emissions. Using a rotation temperature diagram, we derive that the rota- tional temperature and the column density of CHaCN are 244 K and 1.2 ~ 1015 cm-2, respectively. We also suggest that the minor outflow is probably driven by the hy- percompact （HC） HII region A that is inside. We find the molecular gas （traced by ClrO, SO, CH3OH and SO2） surrounding G20.08-0.14N appears to be undergoing bulk rotation. The HCHII region A that is inside is most probably the main source of accretion and heating for G20.08-0.14N.

关键词： ISM: individual objects (G20.08-0.14N) -- ISM: molecules -- radiolines: ISM -- stars: formation-- ISM: kinematics and dynamics

A multiwavelength study of the star forming HⅡ region Sh2-82

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Research in Astronomy and Astrophysics 2012年第6期12卷 651-660页

作者： Nai-Ping Yu jun-jie wang National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China NAOC-TU Joint Center for Astrophysics Lhasa 850000 China

Based on a multiwavelength study, the interstellar medium and young stel- lar objects （YSOs） around the H II region Sh2-82 have been analyzed. Two molecular clumps were found from the archival data of the Galactic Ring Survey, and using the Two Micron All-Sky Survey catalog, we found two corresponding young clusters embedded in the molecular clumps. The very good relations between CO emission, infrared shells and YSOs suggest that it is probably a triggered star formation region from the expansion of Sh2-82. We further used the data from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire from Spitzer to study the YSOs within the two clumps, confirming star formation in this region. By spectral energy distribution fits to each YSO candidate with infrared excess, we derived the slope of the initial mass function. Finally, comparing the H II region＇s dynamical age and the fragmenta- tion time of the molecular shell, we discard the ＂collect and collapse＂ process as being the triggering mechanism for YSO formation. Sh2-82 can be a mixture of other pro- cesses such as radiative-driven implosion and/or collisions with pre-existing clumps.

关键词： ISM: clouds -- nebulae: HII region -- individual: Sh2-82 -- stars:formation

HNCO： a molecule that traces low-velocity shocks

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Research in Astronomy and Astrophysics 2018年第2期18卷 19-36页

作者： Nai-Ping Yu Jing-Long Xu jun-jie wang National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China NAOC-TU Joint Center for Astrophysics Lhasa 850000 China

Using data from Millimetre Astronomy Legacy Team Survey at 90 GHz （MALT90）, we present a molecular line study of a sample of APEX Telescope Large Area Survey of the Galaxy （ATLASGAL） clumps. Twelve emission lines have been detected in all. We found that in most sources, emissions of HC3N, HN13C, CH3CN, HNCO and SiO show more compact distributions than those of HCO＋, HNC, HCN and N2H＋. By comparing with other molecular lines, we found that the abun- dance of HNCO （x（HNCO）） correlates well with other species such as HC3N, HNC, C2H, H13CO＋ and N2H＋. Previous studies indicate the HNCO abundance could be enhanced by shocks. However, in this study, we find the abundance of HNCO does not correlate well with that of SiO, which is also a good tracer of shocks. We suggest this may be because HNCO and SiO trace different parts of shocks. Our analysis indicates that the velocity of a shock traced by HNCO tends to be lower than that traced by SiO. In the low-velocity shocks traced by HNCO, the HNCO abundance increases faster than that of SiO. While in the relatively high-velocity shocks traced by SiO, the SiO abundance increases faster than that of HNCO. We suggest that in the infrared dark cloud MSXDC G331.71＋00.59, high-velocity shocks are destroying the molecule HNCO.

关键词： stars: formation- ISM: abundances- ISM: clouds- ISM: molecules

Highly precise Ti/Pt/Cr/Au thin-film temperature sensor embedded in a microfluidic device

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Rare Metals 2021年第1期40卷 195-201页

作者： jie-jun wang Tao wang Chuan-Gui Wu Wen-Bo Luo Yao Shuai wang-Li Zhang State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of ChinaChengdu 611731China

A multilayer(Ti/Pt/Cr/Au)resistive temperature sensor was proposed and investigated to precisely measure the temperature characteristic in microfluidic *** Ti/Pt/Cr/Au sensor was fabricated by direct current(DC)sputtering,vacuum evaporation and liftoff *** thermal annealing test was conducted in the temperature range of 200-800℃for obtaining an appropriate property of the *** on the experimental results,400℃was selected as the experimental annealing temperature for the Ti/Pt/Cr/Au *** redistribution of structural imperfections and recrystallization promote the density and adhesion of multilayer during the annealing *** the annealing temperature rising,the annealing process leads to through-thickness migration of chromium and partial depletion of the adhesive *** Ti also diffuses into the Pt,which makes the interface ***,the layer remains *** temperature coefficient of resistance(TCR)of the sensors was investigated through the microfluidic testing *** excellent stability and sensitivity of the Ti/Pt/Cr/Au thin-film temperature sensor are ***,the capability of the Ti/Pt/Cr/Au thin-film temperature sensor detecting the sudden temperature change caused by bubble effect is very meaningful to the microfluidic devices.

关键词： Ti/Pt/Cr/Au layer Annealing process Recrystallization Temperature coefficient of resistance(TCR) Microfluidic device

Electrochemical behavior of Ti-6Al-4V alloy in Hank's solution subjected to deep cryogenic treatment

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Rare Metals 2023年第6期42卷 2037-2046页

作者： Kai-Xuan Gu Kai-Kai wang Jian-Peng Zheng Liu-Biao Chen jun-jie wang CAS Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryBeijing100190China University of Chinese Academy of Sciences Beijing100049China

The effect of deep cryogenic treatment(DCT)on the electrochemical behavior of Ti-6Al-4V alloy in Hank's solution was experimentally investigated in the present *** cryogenic treatments at-196℃soaking for 24(DCT-24) and 48(DCT-48) hours were conducted on the commercial annealed Ti-6Al-4V *** methods of polarization and electrochemical impedance spectroscopy(EIS) were employed to evaluate the electrochemical behavior and corrosion ***,atomic force microscopy(AFM) was used to detect the corrosion *** results showed that deep cryogenic treatment shifted the corrosion potentials(E_(corr))to the positive *** corrosion current densities(i_(corr))of samples treated by DCT-24 and DCT-48decreased from 153.1 nA·cm^(-2) in the untreated(UT)sample to 86.3 nA·cm^(-2) and 43.3 nA·cm^(-2),***,the roughness of corrosion surfaces of samples subjected to DCT was smaller than that of the UT sample,which indeed demonstrated the improvement in corrosion resistance of Ti-6Al-4V alloy in Hank's *** results of EIS test indicated that deep cryogenic treatment had no influence on the corrosion mechanism of Ti-6Al-4V alloy in Hank's,while enhanced resistance value of outer porous layer R_p,which makes the surface more efficient to prevent the *** reduction of β-phase particles,improvement in dislocation density and release of residual stress caused by deep cryogenic treatment had great contribution to the improvement in corrosion resistance of Ti-6Al-4V alloy in Hank's solution.

关键词： Ti-6Al-4V alloy Deep cryogenic treatment Polarization Electrochemical impedance spectroscopy(EIS)

Vertical grain-size trend of mouth bar in lacustrine fan delta:Flume experiments

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Petroleum Science 2022年第5期19卷 1964-1977页

作者： Ke Zhang Sheng-He Wu jun-jie wang Yun-jie Xu Zhen-Hua Xu Jia-Jia Zhang State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing102249China College of Geosciences China University of Petroleum(Beijing)Beijing102249China School of Geosciences Yangtze UniversityWuhanHubei 430100China

Field observational previously indicated a mouth bar of a fan delta could exhibit a fining-or coarseningupward trend,which bring a new challenge to the identification of mouth bar in subsurface studies due to the lack of morphological *** studies have indicated that effluent behavior in rivermouth system can affect the vertical grain-size trend of mouth bar,but the drivers and magnitude of this phenomenon are not *** conducted flume experiments to investigate the mechanism and controlling factors of vertical grain-size trend of mouth *** with a steeper slope of the substrate layer,greater discharge,higher sediment/water ratio,and coarser sediment induced a finingupward trend of mouth bar,because the effluent was dominated by strong *** bar in the experiment with a gentler slope of the substrate layer,smaller discharge,lower sediment/water ratio,and finer sediment exhibited a coarsening-upward trend dominated by the friction-dominated *** relationship between the vertical grain-size trend of mouth bar and the gradients of foreset bedding in small-scale flume models and the cut-off of 15°-18°are applicable in natural *** depositional setting to infer depositional process in river-mouth system and analyzing the plane geometry of sandbodies are two steps in the interpretation of ancient fan deltaic rock record.

关键词： Mouth bar Vertical grain-size trend Effluent behavior Inertia Bed friction