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The braking index of PSR B0540-69 and the associated pulsar wind nebula emission after spin-down rate transition 期刊论文 OAI收割
Monthly Notices of the Royal Astronomical Society, 2020, 卷号: 494, 页码: 1865-1870
作者: HXMT

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stars: magnetic field stars: neutron pulsars: general Astrophysics - High Energy Astrophysical Phenomena Abstract: In 2011 December, PSR B054-69 experienced a spin-down rate transition (SRT), after which the spin-down power of the pulsar increased by $\sim 36{{\ \rm per\ cent}}$. About 1000 d after the SRT, the X-ray luminosity of the associated pulsar wind nebula (PWN) was found to brighten by $32\pm 8{{\ \rm per\ cent}}$. After the SRT, the braking index n of PSR B0540-69 changes from n = 2.12 to 0.03 and then keeps this value for about five years before rising to n = 0.9 in the following years. We find that most of the current models have difficulties in explaining the measured braking index. One exceptive model of the braking index evolution is the increasing dipole magnetic field of PSR B0540-69. We suggest that the field increase may result from some instabilities within the pulsar core that enhance the poloidal component at the price of toroidal component of the magnetic field. The increasing dipole magnetic field will result in the X-ray brightening of the PWN. We fit the PWN X-ray light curve by two models: one assumes a constant magnetic field within the PWN during the brightening and the other assumes an enhanced magnetic field proportional to the energy density of the PWN. It appears that the two models fit the data well, though the later model seems to fit the data a bit better. This provides marginal observational evidence that magnetic field in the PWN is generated by the termination shock. Future high-quality and high-cadence data are required to draw a solid conclusion.

Noble metal-based composite nanomaterials fabricated via solution-based approaches 期刊论文 OAI收割
JOURNAL OF MATERIALS CHEMISTRY A, 2015, 卷号: 3, 期号: 7, 页码: 3182-3223
作者: Liu, Hui; Feng, Yan; Chen, Dong; Li, Chengyin; Cui, Penglei

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METHANOL FUEL-CELLS SHAPE-CONTROLLED SYNTHESIS ONE-POT SYNTHESIS C-H ACTIVATION 3-COMPONENT COUPLING REACTION LOW-TEMPERATURE OXIDATION CORE-SHELL NANOPARTICLES AU-FE3O4 DUMBBELL NANOPARTICLES COMPLEX-CATALYZED SYNTHESIS SURFACE-PLASMON RESONANCE

Synthesis of 3-(1H-benzo[d]imidazol-1-yl)isoindolin-1-one derivatives promoted by EtOH-AcOH solvent system 期刊论文 OAI收割
TETRAHEDRON LETTERS, 2013, 卷号: 54, 期号: 23, 页码: 2972-2975
作者: You, Hanyun; Chen, Fanglei; Lei, Min; Hu, Lihong

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收藏 | 浏览/下载：23/0 | 提交时间：2019/01/08

2-Mercaptobenzimidazole Phthalaldehydic acid Isoindolin-l-one Multi-component reactions (MCRs) Green chemistry

Apoptosis induction and G2/M arrest of 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone from Rubia yunnanensis in human cervical cancer HeLa cells 期刊论文 OAI收割
PHARMAZIE, 2013, 卷号: 68, 期号: 4, 页码: 293-299
作者: Zeng, Guang-Zhi; Fan, Jun-Ting; Xu, Jun-Ju; Li, Yan; Tan, Ning-Hua

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2-Methyl-1,3,6-trihydroxy-9,10-anthraquinone (MTA) one of the major components isolated from the traditional Chinese medicine Rubia yunnanensis exhibited inhibitory activity on the proliferation of several human cancer cell lines. The results from an annexin V-FITC (fluoresein-5-isothiocyanate) apoptosis assay and DNA content analysis showed that MTA exerted cytotoxicity via apoptosis induction and G2/M cell cycle arrest in human cervical carcinoma HeLa cells. Further MTA was found to induce apoptosis of HeLa cells through the mitochondria-mediated pathway. It caused the translocation of Bax to the mitochondria and release of cytochrome c into the cytosol which caused the cleavage of caspase and poly(ADP-ribose) polymerase and finally triggered the apoptosis. Furthermore the p53/p21/Cdc2-cyclin B1 signaling was found related to the G2/M arrest caused by MTA. The over-expression of p21 and down-expression of cyclin B1 caused by MTA inactivated the Cdc2-cyclin B1 complex of G2/M checkpoint and finally caused the G2/M arrest in HeLa cells. This study demonstrated that MTA is a potential anti-cancer component of R. yunnanensis a folk anti-cancer herb used in Yunnan China.

Structural design of large aperture rectangular mirror for space telescope (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Civil Engineering and Transportation, ICCET 2012, October 27, 2012 - October 28, 2012, Guilin, China
作者: Li Z.; Li Z.

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Structural design of large aperture mirror is one of the key technologies for space telescope development. To meet the requirements of high stiffness strength and thermal dimensional stability some factors such as support scheme materials selection lightweight design and flexible support design were taken into account. The three supports location of the mirror was determined according to the modal analytical solution. By adjusting the parameters of flexure hinge influences of gravity assembly stress and thermal stress on the mirror were reduced obviously. Finite element analysis (FEA) results indicate that the surface accuracy reach to rms10.2nm and 10.8nm under the gravity along optical axis direction and 5C uniform temperature rise respectively the fundamental frequency of the mirror component is 268Hz. Dynamics test shows that the first order natural frequency is 256Hz which shows an error less than 5% compared to FEA results. (2013) Trans Tech Publications Switzerland.

Structural amelioration of 920 nm optically pumped semiconductor vertical external-cavity surface emitting laser (OPS-VECSEL) (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Energy, Environment and Sustainable Development, EESD 2012, October 12, 2012 - October 14, 2012, Jilin, China
作者: Liu Y.; Liu Y.; Wang L.; Wang L.; Wang L.

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920 nm optically pumped semiconductor vertical external-cavity surface emitting laser (OPS-VECSEL) has an important application in laser display. We constructed and optimized a 920 nm OPS-VECSEL with active region of In0.09Ga0.91As quantum well (QW) system pumped by 808 nm laser diode module. By the finite element method self-consistent solutions of the semiconductor electronic and optical equations are realized to calculate the characteristics parameters of OPS-VECSEL. The performances of device especially the mode the threshold and the optical-optical translation efficiency were analyzed by dealing with different number of QWs (1 2 and 3) in one period QW depth barrier width the component and dimension of the non-absorption layer. We chose an improved structure of them. On this basis we ameliorated the number of QW periods and the simulation showed that in order to obtain high performance device the choice of the number of QW periods must be cautious. (2013) Trans Tech Publications Switzerland.

Catalyst-free one-pot synthesis of isoindolin-1-imine derivatives via three-component reaction 期刊论文 OAI收割
ARKIVOC, 2013, 页码: 413-423
作者: Shen, Sida; Pham Van Khang; Chen, Yijia; Lei, Min; Hu, Lihong

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2-cyanobenzaldehyde 3-methyl-1H-pyrazol-5(4H)-one 1,3-dimethyl-1H-pyrazol-5(4H)-one isoindolin-1-imine multi-component reaction

Accuracy synthesis of a 3-RPS parallel robot based on manufacturing costs (EI CONFERENCE) 会议论文 OAI收割
31st Chinese Control Conference, CCC 2012, July 25, 2012 - July 27, 2012, Hefei, China
Yao T.-K.; Xi Z.; Feng Z.; Zhang L.-M.; Yong W.

收藏 | 浏览/下载：32/0 | 提交时间：2013/03/25

Pose accuracy is an important issue for parallel robot being used as mirror supporting system of telescope. One challenging topic is the accuracy synthesis which deals with the optimal design of the manufacturing and assembling tolerances of each component under the given pose accuracy. First the error model of the 3-RPS parallel robot is built based on total derivation of the kinematic equations. And the error variable of each spherical or rotate joint can be expressed as a single boundary error parameter but not three independent position parameters. Then the accuracy synthesis model is formulated taking the manufacturing costs as the optimization objective and the accuracy requirements as the constraint condition. Finally the genetic algorithm is used to solve the optimization problem and a simulation example is given. The results show that the accuracy synthesis method based on manufacturing costs can satisfy the need of pose accuracy and is better for engineering application than the method based on error sensitivity. 2012 Chinese Assoc of Automati.

Image coding using wavelet-based compressive sampling (EI CONFERENCE) 会议论文 OAI收割
2012 5th International Symposium on Computational Intelligence and Design, ISCID 2012, October 28, 2012 - October 29, 2012, Hangzhou, China
作者: Li J.; Li J.; Li J.

收藏 | 浏览/下载：45/0 | 提交时间：2013/03/25

In this paper we proposed a novel coding scheme is proposed using wavelet-based CS framework for nature image. First two-dimension discrete wavelet transform (DWT) is applied to a nature image for sparse representation. After multi-scale DWT the low-frequency sub-band and high-frequency sub-bands are re-sampled separately. According to the statistical dependences among DWT coefficients we allocate different measurements to low- and high-frequency component. Then the measurements samples can be quantized. The quantize samples are entropy coded and forward correct coding (FEC). Finally the compressed streams are transmitted. At the decoder one can simply reconstruct the image via l1 minimization. Experimental results show that the proposed wavelet-based CS scheme achieves better compression performance against the relevant existing solutions.

A composite hardness stamp in 184 PDMS for nanostructures transfer in high fidelity (EI CONFERENCE) 会议论文 OAI收割
2012 12th IEEE International Conference on Nanotechnology, NANO 2012, August 20, 2012 - August 23, 2012, Birmingham, United kingdom
作者: Du J.; Shi L.; Li S.

收藏 | 浏览/下载：19/0 | 提交时间：2013/03/25

To improve the fidelity of nanostructures in transfer process a composite stamp with reasonable hardness distribution in 184 PDMS used to nanoimprint was studied. The stamp is composed of a stiff 184 PDMS structured layer and a soft 184 PDMS supporter layer. We studied the relationship between the hardness of the 184 PDMS and the proportion of each component in 184 PDMS. The appropriate components proportions of prepolymer and curing agent corresponding to the different region of the composite stamp were presented. The fabrication method of the stamp is also presented. Corresponding experiments were carried out by using this stamp. Kinds of nanostructures were transferred in one inch diameter area with good fidelity. The feature sizes of the structures were less than 100 nm. 2012 IEEE.