Nanjing University

About: Nanjing University is a education organization based out in Nanjing, China. It is known for research contribution in the topics: Catalysis & Adsorption. The organization has 85961 authors who have published 105504 publications receiving 2289036 citations. The organization is also known as: NJU & Nanking University.

Differential emission measure analysis of multiple structural components of coronal mass ejections in the inner corona

Abstract: In this paper, we study the temperature and density properties of multiple structural components of coronal mass ejections (CMEs) using differential emission measure (DEM) analysis. The DEM analysis is based on the six-passband EUV observations of solar corona from the Atmospheric Imaging Assembly on board the Solar Dynamic Observatory. The structural components studied include the hot channel in the core region (presumably the magnetic flux rope of the CME), the bright loop-like leading front (LF), and coronal dimming in the wake of the CME. We find that the presumed flux rope has the highest average temperature (>8 MK) and density (~1.0 × 109 cm–3), resulting in an enhanced emission measure over a broad temperature range (3 ≤ T(MK) ≤ 20). On the other hand, the CME LF has a relatively cool temperature (~2 MK) and a narrow temperature distribution similar to the pre-eruption coronal temperature (1 ≤ T(MK) ≤ 3). The density in the LF, however, is increased by 2%-32% compared with that of the pre-eruption corona, depending on the event and location. In coronal dimmings, the temperature is more broadly distributed (1 ≤ T(MK) ≤ 4), but the density decreases by ~35%-~40%. These observational results show that: (1) CME core regions are significantly heated, presumably through magnetic reconnection; (2) CME LFs are a consequence of compression of ambient plasma caused by the expansion of the CME core region; and (3) the dimmings are largely caused by the plasma rarefaction associated with the eruption.

Assemblies of a New Flexible Multicarboxylate Ligand and d10 Metal Centers toward the Construction of Homochiral Helical Coordination Polymers: Structures, Luminescence, and NLO-Active Properties

Abstract: Hydro(solvo)thermal reactions between a new flexible multicarboxylate ligand of 2,2‘,3,3‘-oxydiphthalic acid (2,2‘,3,3‘-H4ODPA) and M(NO3)2·xH2O (M = Zn, x = 6; M = Cd, x = 4) in the presence of 4,4‘-bipyridine (bpy) afford two novel homochiral helical coordination polymers {[Zn2(2,2‘,3,3‘-ODPA)(bpy)(H2O)3]·(H2O)2 for 1 and [Cd2(2,2‘,3,3‘-ODPA)(bpy)(H2O)3]·(H2O)2 for 2}. Though having almost the same chemical formula, they have different space groups (P212121 for 1 and P21 for 2) and different bridging modes of the 2,2‘,3,3‘-ODPA ligand. Two kinds of homochiral helices (right-handed) are found in both 1 and 2, each of which discriminates only one kind of crystallographical nonequivalent metal atom. 1 has a 2D metal−organic framework and can be seen as the unity of two parallel homochiral Zn1 and Zn2 helices, in which the nodes are etheric oxygen atoms. In contrast, 2 has a 3D metal−organic framework and consists of two partially overlapped homochiral Cd1 and Cd2 helices in the two dimensions. Moreover, me...

Device-free gesture tracking using acoustic signals

Abstract: Device-free gesture tracking is an enabling HCI mechanism for small wearable devices because fingers are too big to control the GUI elements on such small screens, and it is also an important HCI mechanism for medium-to-large size mobile devices because it allows users to provide input without blocking screen view. In this paper, we propose LLAP, a device-free gesture tracking scheme that can be deployed on existing mobile devices as software, without any hardware modification. We use speakers and microphones that already exist on most mobile devices to perform device-free tracking of a hand/finger. The key idea is to use acoustic phase to get fine-grained movement direction and movement distance measurements. LLAP first extracts the sound signal reflected by the moving hand/finger after removing the background sound signals that are relatively consistent over time. LLAP then measures the phase changes of the sound signals caused by hand/finger movements and then converts the phase changes into the distance of the movement. We implemented and evaluated LLAP using commercial-off-the-shelf mobile phones. For 1-D hand movement and 2-D drawing in the air, LLAP has a tracking accuracy of 3.5 mm and 4.6 mm, respectively. Using gesture traces tracked by LLAP, we can recognize the characters and short words drawn in the air with an accuracy of 92.3% and 91.2%, respectively.