Search

Your search keyword '"LI Zhi"' showing total 1,320 results
Start Over Author "LI Zhi" Publisher iop publishing
1,320 results on '"LI Zhi"'

2. Formation of WNL Stars in the MW and LMC Based on the k − ω Model.

Author

Si, Jijuan, Li, Zhi, and Li, Yan

Subjects
*CONVECTION (Astrophysics), *SUPERGIANT stars, *STELLAR mass, *LOW mass stars, *STAR formation
Abstract

We adopt a set of second-order differential equations (k − ω model) to handle core convective overshooting in massive stars, simulate the evolution of nitrogen sequence Wolf–Rayet (WNL) stars with different metallicities and initial masses, both rotating and nonrotating models, and compare the results with the classical overshooting model. The results indicate that, under the same initial conditions, the k − ω model generally produces larger convective cores and wider overshooting regions, thereby increasing the mass ranges and extending the lifetimes of WNL stars, as well as the likelihood of forming WNL stars. The masses and lifetimes of WNL stars both increase with higher metallicities and initial masses. Under higher-metallicity conditions, the two overshooting schemes significantly differ in their impacts on the lifetimes of WNL stars, but are insignificant in the mass ranges of the WNL stars. Rotation may drive the formation of WNL stars in low-mass, metal-poor counterparts, with this effect being more pronounced in the overshooting model. The surface nitrogen of metal-rich WNL stars formed during the main-sequence phase is likely primarily from the CN cycle, while it may come from both the CN and NO cycles for relatively metal-poor counterparts. Our model can effectively explain the distribution of WNL stars in the Milky Way, but appears to have inadequacies in explaining the WNL stars in the LMC. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

3. Early Planet Formation in Embedded Disks. XI. A High-resolution View Toward the BHR 71 Class 0 Protostellar Wide Binary.

Author

Gavino, Sacha, Jørgensen, Jes K., Sharma, Rajeeb, Yang, Yao-Lun, Li, Zhi-Yun, Tobin, John J., Ohashi, Nagayoshi, Takakuwa, Shigehisa, Plunkett, Adele L., Kwon, Woojin, de Gregorio-Monsalvo, Itziar, Lin, Zhe-Yu Daniel, Santamaría-Miranda, Alejandro, Aso, Yusuke, Sai, Jinshi, Aikawa, Yuri, Tomida, Kengo, Koch, Patrick M., Lee, Jeong-Eun, and Lee, Chang Won

Subjects
ANGULAR momentum (Mechanics), CIRCUMSTELLAR matter, ORIGIN of planets, STAR formation, HELICAL structure
Abstract

We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of the binary Class 0 protostellar system BHR 71 IRS1 and IRS2 as part of the Early Planet Formation in Embedded Disks (eDisk) ALMA Large Program. We describe the 12CO (J = 2–1), 13CO (J = 2–1), C18O (J = 2–1), H2CO (J = 32,1–22,0), and SiO (J = 5–4) molecular lines along with the 1.3 mm continuum at high spatial resolution (∼0.″08 or ∼5 au). Dust continuum emission is detected toward BHR 71 IRS1 and IRS2, with a central compact component and extended continuum emission. The compact components are smooth and show no sign of substructures such as spirals, rings, or gaps. However, there is a brightness asymmetry along the minor axis of the presumed disk in IRS1, possibly indicative of an inclined geometrically and optically thick disk-like component. Using a position–velocity diagram analysis of the C18O line, clear Keplerian motions were not detected toward either source. If Keplerian rotationally supported disks are present, they are likely deeply embedded in their envelope. However, we can set upper limits of the central protostellar mass of 0.46 M ⊙ and 0.26 M ⊙ for BHR 71 IRS1 and BHR 71 IRS2, respectively. Outflows traced by 12CO and SiO are detected in both sources. The outflows can be divided into two components, a wide-angle outflow and a jet. In IRS1, the jet exhibits a double helical structure, reflecting the removal of angular momentum from the system. In IRS2, the jet is very collimated and shows a chain of knots, suggesting episodic accretion events. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

10. An improved training framework in neural network model fordisruption prediction and its application on EXL-50

Author

Cai, Jianqing, primary, Liang, Yunfeng, additional, Knieps, Alexander, additional, qi, dongkai, additional, Wang, Erhui, additional, xiang, haoming, additional, liao, liang, additional, huang, jie, additional, yang, jie, additional, Huang, Jia, additional, liu, jianwen, additional, Drews, Philipp, additional, Xu, Shuai, additional, gu, xiang, additional, gao, yichen, additional, luo, yu, additional, and li, zhi, additional

Published
2023
Full Text
View/download PDF

12. Early Planet Formation in Embedded Disks (eDisk). XIV. Flared Dust Distribution and Viscous Accretion Heating of the Disk around R CrA IRS 7B-a.

Author

Takakuwa, Shigehisa, Saigo, Kazuya, Kido, Miyu, Ohashi, Nagayoshi, Tobin, John J., Jørgensen, Jes K., Aikawa, Yuri, Aso, Yusuke, Gavino, Sacha, Han, Ilseung, Koch, Patrick M., Kwon, Woojin, Lee, Chang Won, Lee, Jeong-Eun, Li, Zhi-Yun, Lin, Zhe-Yu Daniel, Looney, Leslie W., Mori, Shoji, Jinshi Sai, and Sharma, Rajeeb

Subjects
ORIGIN of planets, ACCRETION disks, DUST, PROTOSTARS, BRIGHTNESS temperature, RADIATIVE transfer, INTERSTELLAR medium
Abstract

We performed radiative transfer calculations and observing simulations to reproduce the 1.3 mm dust-continuum and C18O (2–1) images in the Class I protostar R CrA IRS7B-a, observed with the ALMA Large Program "Early Planet Formation in Embedded Disks (eDisk)." We found that a dust disk model passively heated by the central protostar cannot reproduce the observed peak brightness temperature of the 1.3 mm continuum emission (∼195 K), regardless of the assumptions about the dust opacity. Our calculation suggests that viscous accretion heating in the disk is required to reproduce the observed high brightness temperature. The observed intensity profile of the 1.3 mm dust-continuum emission along the disk minor axis is skewed toward the far side of the disk. Our modeling reveals that this asymmetric intensity distribution requires flaring of the dust along the disk vertical direction with the scale height following h / r ∼ r 0.3 as a function of radius. These results are in sharp contrast to those of Class II disks, which show geometrically flat dust distributions and lower dust temperatures. From our modeling of the C18O (2–1) emission, the outermost radius of the gas disk is estimated to be ∼80 au, which is larger than that of the dust disk (∼62 au), to reproduce the observed distribution of the C18O (2–1) emission in IRS 7B-a. Our modeling unveils a hot and thick dust disk plus a larger gas disk around one of the eDisk targets, which could be applicable to other protostellar sources in contrast to more evolved sources. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

23. Controlled synthesis of van der Waals CoS2 for improved p-type transistor contact.

Author

Wang, Yao, Liu, Chaocheng, Duan, Hengli, Li, Zhi, Wang, Chao, Tan, Hao, Feng, Sihua, Liu, Ruiqi, Li, Pai, and Yan, Wensheng

Subjects
HOLE mobility, SEMICONDUCTOR devices, VAN der Waals forces, P-type semiconductors, TRANSISTORS, FIELD-effect transistors, ORGANIC field-effect transistors
Abstract

Two-dimensional (2D) van der Waals (vdW) p-type semiconductors have shown attractive application prospects as atomically thin channels in electronic devices. However, the high Schottky hole barrier of p-type semiconductor–metal contacts induced by Fermi-level pinning is hardly removed. Herein, we prepare a vdW 1T-CoS2 nanosheet as the contact electrode of a WSe2 field-effect transistor (FET), which shows a considerably high on/off ratio > 107 and a hole mobility of ∼114.5 cm2 V−1 s−1. The CoS2 nanosheets exhibit metallic conductivity with thickness dependence, which surpasses most 2D transition metal dichalcogenide metals or semimetals. The excellent FET performance of the CoS2-contacted WSe2 FET device can be attributed to the high work function of CoS2, which lowers the Schottky hole barrier. Our work provides an effective method for growing vdW CoS2 and opens up more possibilities for the application of 2D p-type semiconductors in electronic devices. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

24. Early Planet Formation in Embedded Disks (eDisk). X. Compact Disks, Extended Infall, and a Fossil Outburst in the Class I Oph IRS43 Binary.

Author

Narayanan, Suchitra, Williams, Jonathan P., Tobin, John J., Jørgensen, Jes K., Ohashi, Nagayoshi, Lin, Zhe-Yu Daniel, van't Hoff, Merel L. R., Li, Zhi-Yun, Plunkett, Adele L., Looney, Leslie W., Takakuwa, Shigehisa, Yen, Hsi-Wei, Aso, Yusuke, Flores, Christian, Lee, Jeong-Eun, Lai, Shih-Ping, Kwon, Woojin, de Gregorio-Monsalvo, Itziar, Sharma, Rajeeb, and Lee, Chang Won

Subjects
COMPACT discs, ORIGIN of planets, BINARY stars, PROTOSTARS, FOSSILS
Abstract

We present the first results from the Early Planet Formation in Embedded Disks Atacama Large Millimeter/submillimeter Array Large Program toward Oph IRS43, a binary system of solar mass protostars. The 1.3 mm dust continuum observations resolve a compact disk, ∼6 au radius, around the northern component and show that the disk around the southern component is even smaller, ≲3 au. CO, 13CO, and C18O maps reveal a large cavity in a low-mass envelope that shows kinematic signatures of rotation and infall extending out to ∼2000 au. An expanding CO bubble centered on the extrapolated location of the source ∼130 yr ago suggests a recent outburst. Despite the small size of the disks, the overall picture is of a remarkably large and dynamically active region. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

35. Atlas of dynamic spectra of fast radio burst FRB 20201124A

Author

Wang, Bo-Jun, primary, Xu, Heng, additional, Jiang, Jin-Chen, additional, Xu, Jiang-Wei, additional, Niu, Jia-Rui, additional, Chen, Ping, additional, Lee, Ke-Jia, additional, Zhang, Bing, additional, Zhu, Wei-Wei, additional, Dong, Su-Bo, additional, Zhang, Chun-Feng, additional, Fu, Hai, additional, Zhou, De-Jiang, additional, Zhang, Yong-Kun, additional, Wang, Pei, additional, Feng, Yi, additional, Li, Ye, additional, Li, Dong-Zi, additional, Lu, Wen-Bin, additional, Yang, Yuan-Pei, additional, Caballero, R. N., additional, Cai, Ce, additional, Chen, Mao-Zheng, additional, Dai, Zi-Gao, additional, Esamdin, A., additional, Gan, Heng-Qian, additional, Han, Jin-Lin, additional, Hao, Long-Fei, additional, Huang, Yu-Xiang, additional, Jiang, Peng, additional, Li, Cheng-Kui, additional, Li, Di, additional, Li, Hui, additional, Li, Xin-Qiao, additional, Li, Zhi-Xuan, additional, Liu, Zhi-Yong, additional, Luo, Rui, additional, Men, Yun-Peng, additional, Niu, Chen-Hui, additional, Peng, Wen-Xi, additional, Qian, Lei, additional, Song, Li-Ming, additional, Sun, Jing-Hai, additional, Wang, Fa-Yin, additional, Wang, Min, additional, Wang, Na, additional, Wang, Wei-Yang, additional, Wu, Xue-Feng, additional, Xiao, Shuo, additional, Xiong, Shao-Lin, additional, Xu, Yong-Hua, additional, Xu, Ren-Xin, additional, Yang, Jun, additional, Yang, Xuan, additional, Yao, Rui, additional, Yi, Qi-Bin, additional, Yue, You-Ling, additional, Yu, Dong-Jun, additional, Yu, Wen-Fei, additional, Yuan, Jian-Ping, additional, Zhang, Bin-Bin, additional, Zhang, Song-Bo, additional, Zhang, Shuang-Nan, additional, Zhao, Yi, additional, Zheng, Wei-Kang, additional, Zhu, Yan, additional, and Zou, Jin-Hang, additional

Published
2023
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results