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2000 Experience Chinese Culture in the United States──An Interview with Director-General li gang

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China & The World Cultural Exchange 2000年第6期66卷 10-12页

作者： li Shengxian

From the 24th of last August to the 17th of last September, the 2000 Experience Chinese Culture in the United States,a major activity sponsored jointly by the Chinese Ministryof Culture and the Information Office unde... 详细信息

关键词： In li Experience Chinese Culture in the United States An Interview with Director-General li gang

Mutual regulation of microglia and astrocytes after Gas6 inhibits spinal cord injury

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Neural Regeneration Research 2025年第2期20卷 557-573页

作者： Jiewen Chen Xiaolin Zeng Le Wang Wenwu Zhang gang li Xing Cheng Peiqiang Su Yong Wan Xiang li Department of Spine Surgery The First Affiliated HospitalSun Yat-sen UniversityGuangzhouGuangdong ProvinceChina Guangdong Province Key Laboratory of Orthopedics and Traumatology GuangzhouGuangdong ProvinceChina

Invasive inflammation and excessive scar formation are the main reasons for the difficulty in repairing nervous tissue after spinal cord *** and astrocytes play key roles in the spinal cord injury micro-environment and share a close ***,the mechanisms involved remain *** this study,we found that after spinal cord injury,resting microglia(M0)were polarized into pro-inflammatory phenotypes(MG1 and MG3),while resting astrocytes were polarized into reactive and scar-forming *** expression of growth arrest-specific 6(Gas6)and its receptor Axl were significantly down-regulated in microglia and astrocytes after spinal cord *** vitro experiments showed that Gas6 had negative effects on the polarization of reactive astrocytes and pro-inflammatory microglia,and even inhibited the cross-regulation between *** further demonstrated that Gas6 can inhibit the polarization of reactive astrocytes by suppressing the activation of the Yes-associated protein signaling ***,in turn,inhibited the polarization of pro-inflammatory microglia by suppressing the activation of the nuclear factor-κB/p65 and Janus kinase/signal transducer and activator of transcription signaling *** vivo experiments showed that Gas6 inhibited the polarization of pro-inflammatory microglia and reactive astrocytes in the injured spinal cord,thereby promoting tissue repair and motor function ***,Gas6 may play a role in the treatment of spinal cord *** can inhibit the inflammatory pathway of microglia and polarization of astrocytes,attenuate the interaction between microglia and astrocytes in the inflammatory microenvironment,and thereby alleviate local inflammation and reduce scar formation in the spinal cord.

关键词： astrocytes Axl cell polarization Gas6 Hippo signal inflammatory micro-environment intercellular interaction microglia single-cell sequencing spinal cord injury

Particle acceleration and transport in the inner heliosphere

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Science China Earth Sciences 2017年第8期60卷 1440-1465页

作者： li gang School of Geophysics and Information Technology China University of Geosciences (Beijing) Department of Space Science and CSPAR University of Alabama in Huntsville

In the solar system, our Sun is Nature's most efficient particle accelerator. In large solar flares and fast coronal mass ejections(CMEs), protons and heavy ions can be accelerated to over ~GeV/nucleon. Large flares and fast CMEs often occur together. However there are clues that different acceleration mechanisms exist in these two processes. In solar flares, particles are accelerated at magnetic reconnection sites and stochastic acceleration likely dominates. In comparison, at CME-driven shocks,diffusive shock acceleration dominates. Besides solar flares and CMEs, which are transient events, acceleration of particles has also been observed in other places in the solar system, including the solar wind termination shock, planetary bow shocks, and shocks bounding the Corotation Interaction Regions(CIRs). Understanding how particles are accelerated in these places has been a central topic of space physics. However, because observations of energetic particles are often made at spacecraft near the Earth,propagation of energetic particles in the solar wind smears out many distinct features of the acceleration process. The propagation of a charged particle in the solar wind closely relates to the turbulent electric field and magnetic field of the solar wind through particle-wave interaction. A correct interpretation of the observations therefore requires a thorough understanding of the solar wind turbulence. Conversely, one can deduce properties of the solar wind turbulence from energetic particle observations. In this article I briefly review some of the current state of knowledge of particle acceleration and transport in the inner heliosphere and discuss a few topics which may bear the key features to further understand the problem of particle acceleration and transport.

关键词： Solar energetic particles Diffusive shock acceleration Perpendicular diffusion coefficient

On uniqueness and existence of conformally compact Einstein metrics with homogeneous conformal infinity.Ⅱ

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Science China Mathematics 2024年第12期67卷 2789-2822页

作者： gang li School of Mathematics Shandong UniversityJinan250100China

In this paper,we show that for an Sp(k+1)-invariant metric g on S^(4k+3)(k 1)close to the round metric,the conformally compact Einstein(CCE)manifold(M,g)with(S^(4k+3),[?])as its conformal infinity is unique up to ***,by the result in li et al.(2017),g is the Graham-Lee metric(see Graham and Lee(1991))on the unit ball B_(1)■R^(4k+4).We also give an a priori estimate of the Einstein metric *** a byproduct of the a priori estimates,based on the estimate and Graham-Lee and Lee's seminal perturbation results(see Graham and Lee(1991)and Lee(2006)),we directly use the continuity method to obtain an existence result of the non-positively curved CCE metric with prescribed conformal infinity(S^(4k+3),[g])when the metric?is Sp(k+1)-*** also generalize the results to the case of conformal infinity(S^(15),[?])with g a Spin(9)-invariant metric in the appendix.

关键词： conformally compact Einstein manifolds prescribed conformal infinity uniqueness and existence of CCE filling-in two-point boundary value problem of nonlinear ODE systems volume comparison total variation

Market-based control strategy for long-span structures considering the multi-time delay issue

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Earthquake Engineering and Engineering Vibration 2017年第1期16卷 153-164页

作者： li Hongnan Song Jianzhu li gang School of Civil Engineering Liaoning Collaborative Innovation Center for Engineering Disaster Prevention and MitigationDalian University of TechnologyDalian 116024China

To solve the different time delays that exist in the control device installed on spatial structures, in this study, discrete analysis using a 2N precise algorithm was selected to solve the multi-time-delay issue for long-span structures based on the market-based control （MBC） method. The concept of interval mixed energy was introduced from computational structural mechanics and optimal control research areas, and it translates the design of the MBC multi-time-delay controller into a solution for the segment matrix. This approach transforms the serial algorithm in time to parallel computing in space, greatly improving the solving efficiency and numerical stability. The designed controller is able to consider the issue of time delay with a linear controlling force combination and is especially effective for large time-delay conditions. A numerical example of a long-span structure was selected to demonstrate the effectiveness of the presented controller, and the time delay was found to have a significant impact on the results.

关键词： market based control multi-time delay interval mixed energy 2N precise algorithm discrete system

Novel Model Using Kernel Function and Local Intensity Information for Noise Image Segmentation

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Tsinghua Science and Technology 2018年第3期23卷 303-314页

作者： gang li Haifang li ling Zhang College of Computer Science and Technology Taiyuan University of Technology

It remains a challenging task to segment images that are distorted by noise and intensity *** overcome these problems, in this paper, we present a novel region-based active contour model based on local intensity information and a kernel metric. By introducing intensity information about the local region, the proposed model can accurately segment images with intensity inhomogeneity. To enhance the model＇s robustness to noise and outliers, we introduce a kernel metric as its objective functional. To more accurately detect boundaries, we apply convex optimization to this new model, which uses a weighted total-variation norm given by an edge indicator function. Lastly, we use the split Bregman iteration method to obtain the numerical solution. We conducted an extensive series of experiments on both synthetic and real images to evaluate our proposed method, and the results demonstrate significant improvements in terms of efficiency and accuracy, compared with the performance of currently popular methods.

关键词： kernel metric image segmentation local intensity information convex optimization

Treatment of oilfield produced water by anaerobic process coupled with micro-electrolysis

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Journal of Environmental Sciences 2010年第12期22卷 1875-1882页

作者： gang li Shuhai Guo Fengmei li Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 China. Graduate School of Chinese Academy of Sciences Beijing 100039 China

Treatment of oilfield produced water was investigated using an anaerobic process coupled with micro-electrolysis （ME）, focusing on changes in chemical oxygen demand （COD） and biodegradability. Results showed that COD exhibited an abnormal change in the single anaerobic system in which it increased within the first 168 hr, but then decreased to 222 mg/L after 360 hr. The biological oxygen demand （five-day）（BOD5）/COD ratio of the water increased from 0.05 to 0.15. Hydrocarbons in the wastewater, such as pectin, degraded to small molecules during the hydrolytic acidification process. Comparatively, the effect of ME was also investigated. The COD underwent a slight decrease and the BOD5/COD ratio of the water improved from 0,05 to 0.17 after ME. Removal of COD was 38.3% under the idealized ME conditions （pH 6.0）, using iron and active carbon （80 and 40 g/L, respectively）. Coupling the anaerobic process with ME accelerated the COD removal ratio （average removal was 53.3%）. Gas chromatography/mass spectrometry was used to analyze organic species conversion. This integrated system appeared to be a useful option for the treatment of water produced in oilfields.

关键词： heavy oil produced water anaerobic system micro-electrolysis biodegradability

Precession effects on a liquid planetary core

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Research in Astronomy and Astrophysics 2018年第2期18卷 115-124页

作者： Min liu li-gang li Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China University of Chinese Academy of Sciences Beijing 100049 China

Motivated by the desire to understand the rich dynamics of precessionally driven flow in a liquid planetary core, we investigate, through numerical simulations, the precessing fluid motion in a ro- taring cylindrical annulus, which simultaneously possesses slow precession. The same problem has been studied extensively in cylinders, where the precessing flow is characterized by three key parameters： the Ekman number E, the Poincar6 number Po and the radius-height aspect ratio F. While in an annulus, there is another parameter, the inner-radius-height aspect ratio T, which also plays an important role in controlling the structure and evolution of the flow. By decomposing the nonlinear solution into a set of inertial modes, we demonstrate the properties of both weakly and moderately precessing flows. It is found that, when the precessional force is weak, the flow is stable with a constant amplitude of kinetic energy. As the precessional force increases, our simulation suggests that the nonlinear interaction be- tween the boundary effects and the inertial modes can trigger more turbulence, introducing a transitional regime of rich dynamics to disordered flow. The inertial mode u111, followed by u113 or u112, always dominates the precessing flow when 0.001 ≤Po ≤ 0.05, ranging from weak to moderate precession. Moreover, the precessing flow in an annulus shows more stability than in a cylinder which is likely to be caused by the effect of the inner boundary that restricts the growth of resonant and non-resonant inertial modes. Furthermore, the mechanism of triadic resonance is not found in the transitional regime from a laminar to disordered flow.

关键词： Astrometry and Celestial Mechanics: terrestrial planets -- planets and satellites: interiors-- planets and satellites: instabilities: waves

Nanomorphology in A–D–A type small molecular acceptors-based bulk heterojunction polymer solar cells

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Journal of Energy Chemistry 2019年第8期28卷 104-123,I0001,I0005页

作者： Delong liu Ying Zhang gang li The Department of Electronic and Information Engineering The Hong Kong Polytechnic UniversityHong Kong 999077 China The Department of Electronic and Information Engineering The Hong Kong Polytechnic University Shenzhen Research InstituteShenzhen 518057Guangdong China

Recent developments in acceptor–donor–acceptor(A–D–A) type non-fullerene acceptors have led to substantial improvements in bulk-heterojunction polymer solar cells efficiency. The device performance strongly depends on photoactive layer morphology, as the molecular packing, donor–acceptor interface and phase separation significantly affect the charge-transfer states and charge carrier dynamics. In this review, we start with a brief introduction of the techniques most effectively utilized to characterize multiphase morphology. Then, we summarize recent progress in A–D–A type acceptors, with the emphasis on understanding the molecular structure–morphology–performance relationships. Finally, an outlook on correlating morphological characteristics with photovoltage losses is presented for further improving device performance.

关键词： Polymer solar cells Bulk heterojunction Nanomorphology Non-fullerene acceptor A–D–A type small molecules