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172 results on '"Ding, Bingbing"'

1. Global smooth solutions of 2D quasilinear wave equations with higher order null conditions and short pulse initial data

Author

Ding, Bingbing, Xin, Zhouping, and Yin, Huicheng

Subjects
Mathematics - Analysis of PDEs
Abstract

For the short pulse initial data with a first order outgoing constraint condition and optimal orders of smallness, we establish the global existence of smooth solutions to 2D quasilinear wave equations with higher order null conditions. Such kinds of wave equations include 2D relativistic membrane equations, 2D membrane equations, and some 2D quasilinear equations which come from the nonlinear Maxwell equations in electromagnetic theory or from the corresponding Lagrangian functionals as perturbations of the Lagrangian densities of linear wave operators. The main ingredients of the analysis here include looking for a new good unknown, finding some key identities based on the higher order null conditions and the resulting null frames, as well as overcoming the difficulties due to the slow decay of solutions to the 2-D wave equation, so that the solutions can be estimated precisely.

Published
2024

2. Global smooth solutions to 2D semilinear wave equations with large data

Author

Ding, Bingbing, Dong, Shijie, and Xu, Gang

Subjects
Mathematics - Analysis of PDEs
Abstract

We are interested in coupled semi-linear wave equations satisfying the null condition in two space dimensions, a basic model in nonlinear wave equations. Our aim is to establish global existence of smooth solutions to this system with large initial data of short pulse type. Major difficulties arise due to the largeness of initial data and the slow decay nature of 2D wave equations. To overcome the difficulties, by careful examination of the local solutions, we adapt various vector-field methods to different spacetime regions with several novel weighted energy estimates.

Published
2023

4. Global smooth solutions to 4D quasilinear wave equations with short pulse initial data

Author

Ding, Bingbing, Xin, Zhouping, and Yin, Huicheng

Subjects
Mathematics - Analysis of PDEs
Abstract

In this paper, we establish the global existence of smooth solutions to general 4D quasilinear wave equations satisfying the first null condition with the short pulse initial data. Although the global existence of small data solutions to 4D quasilinear wave equations holds true without any requirement of null conditions, yet for short pulse data, in general, it is sufficient and necessary to require the fulfillment of the first null condition to have global smooth solutions. It is noted that short pulse data are extensions of a class of spherically symmetric data, for which the smallness restrictions are imposed on angular directions and along the outgoing directional derivative $\partial_t+\partial_r$, but the largeness is kept for the incoming directional derivative $\partial_t-\partial_r$. We expect that here methods can be applied to study the global smooth solution or blowup problem with short pulse initial data for the general 2D and 3D quasilinear wave equations when the corresponding null conditions hold or not. On the other hand, as some direct applications of our main results, one can show that for the short pulse initial data, the smooth solutions to the 4D irrotational compressible Euler equations for Chaplygin gases, 4D nonlinear membrane equations and 4D relativistic membrane equations exist globally since their nonlinearities satisfy the first null condition; while the smooth solutions to the 4D irrotational compressible Euler equations for polytropic gases generally blow up in finite time since the corresponding first null condition does not hold.

Published
2023

5. On the critical exponent $p_c$ of the 3D quasilinear wave equation $-\big(1+(\partial_t\phi)^p\big)\partial_t^2\phi+\Delta\phi=0$ with short pulse initial data. I, global existence

Author

Ding, Bingbing, Lu, Yu, and Yin, Huicheng

Subjects
Mathematics - Analysis of PDEs
Abstract

For the 3D quasilinear wave equation $-\big(1+(\partial_t\phi)^p\big)\partial_t^2\phi+\Delta\phi=0$ with the short pulse initial data $(\phi,\partial_t\phi)(1,x)=\big(\delta^{2-\varepsilon_0}\phi_0(\frac{r-1}{\delta},\omega), \delta^{1-\varepsilon_0}\phi_1(\frac{r-1}{\delta},\omega)\big)$, where $p\in\mathbb N$, $p\geq 2$, $0<\varepsilon_0<1$, $r=|x|$, $\omega= \frac{x}{r}\in\mathbb S^2$, and $\delta>0$ is sufficiently small, under the outgoing constraint condition $(\partial_t+\partial_r)^k\phi(1,x)=O(\delta^{2-\varepsilon_0})$ for $k=1,2$, we will establish the global existence of smooth large data solution $\phi$ when $p>p_c$ with $p_c=\frac{1}{1-\varepsilon_0}$ being the critical exponent. In the forthcoming paper, when $1\leq p\leq p_c$, we show the formation of the outgoing shock before the time $t=2$ under the suitable assumptions of $(\phi_0,\phi_1)$.

Published
2022

6. Ecosystem Service Functions in the Upper Reaches of the Yellow River in Sichuan Based on Land Use Change Value Evaluation

Author

XU Nuojin, DING Bingbing, YU Xinxiao, JIA Guodong, FENG Yankai, and LIN Jiawen

Subjects
ecosystem service value, the upper reaches of the yellow river in sichuan, land use, value equivalent, Environmental sciences, GE1-350, Agriculture
Abstract

[Objective] To quantitatively study the relationship between land use change and ecosystem service value in Sichuan section of the upper reaches of the Yellow River in the past 20 years, and to evaluate the effect of comprehensive ecological management in this section, so as to provided a basis for improving ethnic regional spatial planning, ecological environmental protection and management, and promoted the high-quality development of the Yellow River Basin. [Methods] Using the land use data of the upper reaches of the Yellow River in Sichuan in 2000, 2010 and 2020, land use change was analyzed based on land use dynamic attitude and land use matrix, and the economic value of the ecosystem service value equivalent per unit area of the terrestrial ecosystem in China was revised. The effects of land use change on the ecosystem service value in the upper reaches of the Yellow River from 2000 to 2020 in Sichuan were quantitatively studied. [Results] (1) From 2000 to 2020, the land use area of forest, desert, wetland and water system in the upper reaches of the Yellow River in Sichuan showed an increasing trend, while the land use area of cultivated land, shrub, grassland and glacial and snow in the upper reaches of the Yellow River showed a decreasing trend, and the land use change in 2010—2020 was more significant than that in 2000—2010. (2) The ecosystem service value of the upper reaches of the Yellow River in Sichuan in 2000, 2010 and 2020, was 1.27×1010, 2.51×1010, 3.92×1010 yuan, respectively, showing an increasing trend. The sensitivity analysis showed that the analysis results were reliable. Amongall land use types, grassland made the most significant contribution to total ecosystem value, and the contribution rate of grassland ecological service was 93.90% and 72.90% in 2000—2010 and 2010—2020, respectively, followed by wetland and forest land. (3) In the study area, the value of each individual ecosystem service showed an increasing trend in the past 20 years, and the sub-value of regional ecological service function was regulatory service>support service>supply service>cultural service. Among the 11 individual functions, the significant service value was climate regulation, hydrology regulation, soil conservation and biodiversity. The sum of the four items accounted for more than 69.50% of the total value. Land use change in the upper reaches of the Yellow River in Sichuan affected the changes of regional ecosystem service value, and grassland was the most significant, followed by wetland and forest land. [Conclusion] The results showed that the results of ecological governance in the past 20 years have been gradually enhanced, and the ecological environment has continuously improved.

Published
2024
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7. On global smooth solutions to the 2D isentropic and irrotational Chaplygin gases with short pulse data

Author

Ding, Bingbing, Xin, Zhouping, and Yin, Huicheng

Subjects
Mathematics - Analysis of PDEs
Abstract

This paper establishes the global existence of smooth solutions to the 2D isentropic and irrotational Euler equations for Chaplygin gases with a general class of short pulse initial data, which, in particular, resolves in this special case, the Majda's conjecture on the non-formation of shock waves of solutions from smooth initial data for multi-dimensional nonlinear symmetric systems which are totally linearly degenerate. Comparing to the 4D case, the major difficulties in this paper are caused by the slower time decay and the largeness of the solutions to the 2D quasilinear wave equation, some new auxiliary energies and multipliers are introduced to overcome these difficulties.

Published
2022

11. Thermal Modulation of Exciton Recombination for High‐Temperature Ultra‐Long Afterglow.

Author

Jiang, Ping, Ding, Bingbing, Yao, Jiayi, Zhou, Lei, He, Zhenyi, Huang, Zizhao, Yin, Chenjia, Tian, He, and Ma, Xiang

Abstract

Developing smart materials with tunable high‐temperature afterglow (HTA) luminescence remains a formidable challenge. This study presents a metal‐free doping system using boric acid as matrix and polycyclic aromatic hydrocarbons as dopants. This composition achieves dynamically tunable afterglow combining a bright blue HTA lasting for over ten seconds even at 150 °C and an ultra‐long yellow room‐temperature phosphorescence below 110 °C. The observed HTA is attributed to the thermally released exciton recombination within the dopant molecules, which shows excellent temperature tolerance compared to traditional triplet related phosphorescence and thermally activated delayed fluorescence. The planarity of dopants is extensively investigated playing a pivotal role in modulating Dexter electron transfer (ET) for capturing released electrons and thereby affecting the overall performance of tunable HTA. This work provides an efficient and universal doping strategy to engineer tunable HTA through the synergistic action of thermally releasing electrons, Dexter ET and exciton recombination. [ABSTRACT FROM AUTHOR]

Published
2024
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19. Blowup of smooth solutions for general 2-D quasilinear wave equations with small initial data

Author

Ding, Bingbing, Witt, Ingo, and Yin, Huicheng

Subjects
Mathematics - Analysis of PDEs, 35L05, 35L72
Abstract

For the 2-D quasilinear wave equation $\displaystyle \sum_{i,j=0}^2g_{ij}(\nabla u)\partial_{ij}u=0$ with coefficients independent of the solution $u$, a blowup result for small data solutions has been established in [1,2] provided that the null condition does not hold and a generic nondegeneracy condition on the initial data is fulfilled. In this paper, we are concerned with the more general 2-D quasilinear wave equation $\displaystyle \sum_{i,j=0}^2g_{ij}(u, \nabla u)\partial_{ij}u=0$ with coefficients that depend simultaneously on $u$ and $\nabla u$. When the null condition does not hold and a suitable nondegeneracy condition on the initial data is satisfied, we show that smooth small data solutions blow up in finite time. Furthermore, we derive an explicit expression for the lifespan and establish the blowup mechanism., Comment: 27 pages

Published
2013

20. Blowup of classical solutions for a class of 3-D quasilinear wave equations with small initial data

Author

Ding, Bingbing, Witt, Ingo, and Yin, Huicheng

Subjects
Mathematics - Analysis of PDEs, 35L65, 35J70, 35R35
Abstract

This paper is concerned with the small smooth data problem for the 3-D nonlinear wave equation $\partial_t^2u-\left (1+u+\p_t u\right)\Delta u=0$. This equation is prototypical of the more general equation $\dsize\sum_{i,j=0}^3g_{ij}(u, \nabla u)\partial_{ij}u=0$, where $x_0=t$ and $g_{ij}(u, \nabla u)=c_{ij}+d_{ij}u+\dsize\sum_{k=0}^3e_{ij}^k\partial_ku+O(|u|^2+|\nabla u|^2)$ are smooth functions of their arguments, with $c_{ij}, d_{ij}$ and $e_{ij}^k$ being constants, and $d_{ij}\neq0$ for some $(i,j)$; moreover, $\dsize\sum_{i,j,k=0}^3e_{ij}^k(\partial_ku)\p_{ij} u$ does not fulfill the null condition. For the 3-D nonlinear wave equations $\partial_t^2u-\left (1+u\right)\Delta u=0$ and $\partial_t^2u-\left (1+\partial_t u\right)\Delta u=0$, H. Lindblad, S. Alinhac, and F. John proved and disproved, respectively, the global existence of small smooth data solutions. For radial initial data, we show that the small smooth data solution of $\partial_t^2u-\left(1+u+\partial_t u\right)\Delta u=0$ blows up in finite time. The explicit expression of the asymptotic lifespan $T_{\varepsilon}$ as $\varepsilon\to0^+$ is also given., Comment: 20 pages, 2 figures

Published
2013

22. On the lifespan of and the blowup mechanism for smooth solutions to a class of 2-D nonlinear wave equations with small initial data

Author

Ding, Bingbing, Witt, Ingo, and Yin, Huicheng

Subjects
Mathematics - Analysis of PDEs, 35L65, 35J70, 35R35
Abstract

This paper is concerned with the lifespan and the blowup mechanism for smooth solutions to the 2-D nonlinear wave equation $\p_t^2u-\ds\sum_{i=1}^2\p_i(c_i^2(u)\p_iu)$ $=0$, where $c_i(u)\in C^{\infty}(\Bbb R^n)$, $c_i(0)\neq 0$, and $(c_1'(0))^2+(c_2'(0))^2\neq 0$. This equation has an interesting physics background as it arises from the pressure-gradient model in compressible fluid dynamics and also in nonlinear variational wave equations. Under the initial condition $(u(0,x), \p_tu(0,x))=(\ve u_0(x), \ve u_1(x))$ with $u_0(x), u_1(x)\in C_0^{\infty}(\Bbb R^2)$, and $\ve>0$ is small, we will show that the classical solution $u(t,x)$ stops to be smooth at some finite time $T_{\ve}$. Moreover, blowup occurs due to the formation of a singularity of the first-order derivatives $\na_{t,x}u(t,x)$, while $u(t,x)$ itself is continuous up to the blowup time $T_{\ve}$., Comment: 22 pages

Published
2012

23. A 3D Phosphorescent Supramolecular Organic Framework in Aqueous Solution.

Author

Yin, Chenjia, Yan, Zi‐Ang, Yan, Ruijian, Xu, Chen, Ding, Bingbing, Ji, Yuanhui, and Ma, Xiang

Subjects
PHOSPHORESCENCE, PHOSPHORESCENCE spectroscopy, FLUORESCENCE resonance energy transfer, DELAYED fluorescence, AQUEOUS solutions, STOKES shift, CHARGE transfer
Abstract

Supramolecular organic framework (SOF) has recently garnered significant research interest in the field of luminescent materials. However, SOF with room‐temperature phosphorescence emission in solution is very rare due to the quenching of dissolved oxygen and free molecular motions, which would lead to nonradiative deactivation of triplet exciton in liquid state. In this work, a 3D cationic phosphorescent SOF is synthesized through host‐guest interaction between CB[8] and a tetrahedral monomer TBBP, which can rapidly adsorb anionic guests in solution. When anionic dyes are introduced, triplet to singlet Förster resonance energy transfer (TS‐FRET) in solution can be achieved, and delayed fluorescence with large Stokes shift can be realized. Additionally, when anionic drugs are introduced, the phosphorescence of TBBP‐CB[8] can be quenched due to charge transfer, enabling the detection of drugs through phosphorescence signals. Taking advantage of the fast adsorption property of 3D SOF, an INHIBIT logic gate with three inputs and two outputs is constructed. These findings provide a novel method to prepare phosphorescent functional materials and a new pathway to construct TS‐FRET system in solution. [ABSTRACT FROM AUTHOR]

Published
2024
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24. Ecosystem Service Functions in the Upper Reaches of the Yellow River in ichuan Based on Land Use Change Value Evaluation.

Author

XU Nuojin, DING Bingbing, YU Xinxiao, JIA Guodong, FENG Yankai, and LIN Jiawen

Abstract

[Objective] To quantitatively study the relationship between land use change and ecosystem service value in Sichuan section of the upper reaches of the Yellow River in the past 20 years, and to evaluate the effect of comprehensive ecological management in this section, so as to provided a basis for improving ethnic regional spatial planning, ecological environmental protection and management, and promoted the high-quality development of the Yellow River Basin. [Methods] Using the land use data of the upper reaches of the Yellow River in Sichuan in 2000, 2010 and 2020, land use change was analyzed based on land use dynamic attitude and land use matrix, and the economic value of the ecosystem service value equivalent per unit area of the terrestrial ecosystem in China was revised. The effects of land use change on the ecosystem service value in the upper reaches of the Yellow River from 2000 to 2020 in Sichuan were quantitatively studied. [Results] (1) From 2000 to 2020, the land use area of forest, desert, wetland and water system in the upper reaches of the Yellow River in Sichuan showed an increasing trend, while the land use area of cultivated land, shrub, grassland and glacial and snow in the upper reaches of the Yellow River showed a decreasing trend, and the land use change in 2010-2020 was more significant than that in 2000-2010. (2) The ecosystem service value of the upper reaches of the Yellow River in Sichuan in 2000, 2010 and 2020, was 1.27X1010, 2.51 X1010, 3.92X1010 yuan, respectively, showing an increasing trend. The sensitivity analysis showed that he analysis results were reliable. Among all land use types, grassland made the most significant contribution o total ecosystem value, and the contribution rate of grassland ecological service was 93.90% and 72.90% in 2000-2010 and 2010-2020, respectively, followed by wetland and forest land. (3) In the study area, the value of each individual ecosystem service showed an increasing trend in the past 20 years, and the sub-value of regional ecological service function was regulatory service > support service > supply service > cultural service. Among the 11 individual functions, the significant service value was climate regulation, hydrology regulation, soil conservation and biodiversity. The sum of the four items accounted for more than 69.50% of he total value. Land use change in the upper reaches of the Yellow River in Sichuan affected the changes of regional ecosystem service value, and grassland was the most significant, followed by wetland and forest and. [Conclusion] The results showed that the results of ecological governance in the past 20 years have been gradually enhanced, and the ecological environment has continuously improved. [ABSTRACT FROM AUTHOR]

Published
2024
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28. Neural Network With Hierarchical Attention Mechanism for Contextual Topic Dialogue Generation

Author

Ding Bingbing and Xiao Sun

Subjects
topic, General Computer Science, General Engineering, dialogue generation, General Materials Science, hierarchical attention, Electrical engineering. Electronics. Nuclear engineering, Dialogue context, TK1-9971
Abstract

The encoder-decoder model has achieved remarkable results in natural language generation. However, in the dialogue generation work, we often ignore the influence of the dialogue context information and topic information in the generation, resulting in the generated replies not close to the context or lack of topic information leads to general responses. In this work, we study the generation of multi-turn dialogues based on a large corpus and take advantage of the context information and topic information of the conversation in the process of dialogue generation to generate more coherent context-sensitive responses. We improve upon existing models and attention mechanisms and propose a new hierarchical model to better solve the problem of dialogue context (the HAT model). This method enables the model to obtain more contextual information when processing and improves the ability of the model in terms of contextual relevance to produce high-quality responses. In addition, to address the absence of topics in the responses, we pre-train the LDA(Latent Dirichlet Allocation) topic model to extract topic words of the dialogue content and retain as much topic information of dialogue as possible. Our model is extensively tested in several corpora, and the experiments illustrate that our model is superior to most hierarchical and non-hierarchical models with respect to multiple evaluation metrics.

Published
2022

42. Novel near-infrared II aggregation-induced emission dots for in vivo bioimaging

Author

Lin, Jiacheng, Zeng, Xiaodong, Xiao, Yuling, Tang, Lin, Nong, Jinxia, Liu, Yufang, Zhou, Hui, Ding, Bingbing, Xu, Fuchun, Tong, Hanxing, Deng, Zixin, Hong, Xuechuan, Zhou, Hui [0000-0001-7332-4936], Hong, Xuechuan [0000-0001-6834-3278], and Apollo - University of Cambridge Repository

Subjects
FOS: Nanotechnology, 34 Chemical Sciences, Nanotechnology, Bioengineering, Digestive Diseases
Abstract

Near-infrared II fluorescence imaging holds great promise for in vivo imaging and imaging-guided surgery with deep penetration and high spatiotemporal resolution. However, most NIR-II aromatic luminophores suffer from the notorious aggregation-caused quenching (ACQ) effect in the aqueous solution, which largely hinders their biomedical application in vivo. In this study, the first NIR-II organic aggregation-induced emission (AIE) fluorophore (HLZ-BTED), encapsulated as nanoparticles (HLZ-BTED dots) for in vivo biomedical imaging, was designed and synthesized. The NIR-II AIE HLZ-BTED dots showed high temporal resolution, high photostability, outstanding water-solubility and biocompatibility in vitro and in vivo. The HLZ-BTED dots were further used for long-term breast tumor imaging and visualizing tumor-feeding blood vessels, long-term hind limb vasculature and incomplete hind limb ischemia. More importantly, as a proof-of-concept, this is the first time that non-invasive and real-time NIR-II imaging of the gastrointestinal tract in health and disease has been performed, making the AIE dots a promising tool for gastrointestinal (GI) tract research, such as understanding the healthy status of GI peristalsis, diagnosing and evaluating intestinal motility dysfunction, and assessing drug effects on intestinal obstruction.

Published
2020
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43. Amphiphilic Cyclopeptide‐Dyes: Smart Self‐Assembly Amphiphilic Cyclopeptide‐Dye for Near‐Infrared Window‐II Imaging (Adv. Mater. 16/2021)

Author

Chen, Hao, primary, Shou, Kangquan, additional, Chen, Si, additional, Qu, Chunrong, additional, Wang, Zhiming, additional, Jiang, Lei, additional, Zhu, Mark, additional, Ding, Bingbing, additional, Qian, Kun, additional, Ji, Aiyan, additional, Lou, Hongyue, additional, Tong, Ling, additional, Hsu, Alexander, additional, Wang, Yuebing, additional, Felsher, Dean W., additional, Hu, Zhenhua, additional, Tian, Jie, additional, and Cheng, Zhen, additional

Published
2021
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44. Smart Self‐Assembly Amphiphilic Cyclopeptide‐Dye for Near‐Infrared Window‐II Imaging

Author

Chen, Hao, primary, Shou, Kangquan, additional, Chen, Si, additional, Qu, Chunrong, additional, Wang, Zhiming, additional, Jiang, Lei, additional, Zhu, Mark, additional, Ding, Bingbing, additional, Qian, Kun, additional, Ji, Aiyan, additional, Lou, Hongyue, additional, Tong, Ling, additional, Hsu, Alexander, additional, Wang, Yuebing, additional, Felsher, Dean W., additional, Hu, Zhenhua, additional, Tian, Jie, additional, and Cheng, Zhen, additional

Published
2021
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