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Study on Model of Indoor Air Pollution Forecast for Decoration Under Natural Ventilation Condition

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Biomedical and Environmental Sciences 2005年第5期18卷 345-348页

作者： yan-feng HONG XUN chen NING XU Institute for Environmental Health and Related Product Safety Chinese Center for Disease Control and Prevention Beijing 100050 China

To establish the model of indoor air pollution forecast for decoration. Methods The model was based on the balance model for diffusing mass. Results The data between testing concentration and estimating concentration were compared. The maximal error was less than 30% and average error was 14.6%. Conclusion The model can easily predict whether the pollution for decoration exceeds the standard and how long the room is decorated.

关键词： Air pollution indoor Model Natural ventilation

Diet-induced hyperhomocysteinemia exacerbates vascular reverse remodeling of balloon-injured arteries in rat

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Chinese Medical Journal 2008年第22期121卷 2265-2271页

作者： GUO yan-hong chen feng-ying WANG Gui-song chen Li GAO Wei Department of Cardiology Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Science Ministry of Education Beijing 100191 China

Background While hyperhomocysteinemia is associated with an increased risk of cardiovascular diseases, the effect of hyperhomocysteinemia on the vascular adventitia and vessel remodeling has not been clearly demonstrated. We investigated the effect of the hyperhomocysteinemia on adventitial hyperplasia and vascular remodeling following balloon injury in rats and the underlying mechanisms. Methods Rats were fed with diet containing methionine for 4 weeks to increase plasma homocysteine before balloon injury. Vascular geometrical changes were assessed at different time points following balloon injury. The collagen deposition was determined by picrosirius red staining and immunohistochemical staining. Results When compared with normal diet group, moderate hyperhomocysteinemia in methionine diet group significantly exacerbated adventitial hyperplasia at day 7 and collagen deposition mainly in the adventitia at day 28 following balloon injury. The increased plasma homocysteine level significantly increased collagen deposition in the adventitia. There was a negative correlation （r=-0.698; P〈0.01） between the luminal area and the collagen content in the adventitia on day 28 following balloon injury. In cultured adventitial fibroblasts isolated from rat aorta, 100 pmol/L L-homocysteine （L-Hcy） significantly down-regulated matrix metalloproteinase-2 activity by 43% as determined by in vitro gelatin zymography （P 〈0.05） and up-regulated the expression of collagen type I by 187% （P 〈0.05） assessed by Western blotting. Conclusions Hyperhomocysteinemia exacerbated vascular constrictive remodeling by accelerated neointima formation and collagen accumulation in the adventitia. Increased collagen deposition may be the underlying mechanism.

关键词： homocysteine arteries adventitia collagen matrix metalloproteinase

Symmetry selective directionality in near-field acoustics

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National Science Review 2020年第6期7卷 1024-1035页

作者： yang Long Hao Ge Danmei Zhang Xiangyuan Xu Jie Ren Ming-Hui Lu Ming Bao Hong chen yan-feng chen Center for Phononics and Thermal Energy Science China-EU Joint Center for Nanophononics Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology School of Physics Sciences and Engineering Tongji University Department of Materials Science and Engineering College of Engineering and Applied Sciences and National Laboratory of Solid State Microstructures Nanjing University Key Laboratory of Noise and Vibration Research Institute of Acoustics Chinese Academy of Sciences Collaborative Innovation Center of Advanced Microstructures Nanjing University Key Laboratory of Noise and Vibration Research Institute of Acoustics Chinese Academy of Sciences Beijing 100190 China and4Collaborative Innovation Center of Advanced Microstructures Nanjing University

Understanding unidirectional and topological wave phenomena requires the unveiling of intrinsic geometry and symmetry for wave dynamics. This is essential yet challenging for the flexible control of near-field evanescent waves, highly desirable in broad practical scenarios ranging from information communication to energy radiation. However, exploitations of near-field waves are limited by a lack of fundamental understanding about inherent near-field symmetry and directional coupling at sub-wavelengths, especially for longitudinal waves. Here, based on the acoustic wave platform, we show the efficient selective couplings enabled by near-field symmetry properties. Based on the inherent symmetry properties of three geometrically orthogonal vectors in near-field acoustics, we successfully realize acoustic Janus, Huygens,spin sources and quadrupole hybrid sources, respectively. Moreover, we experimentally demonstrate fertile symmetry selective directionality of those evanescent modes, supported by two opposite meta-surfaces. The symmetry properties of the near-field acoustic spin angular momenta are revealed by directly measuring local vectorial fields. Our findings advance the understanding of symmetries in near-field physics, supply feasible approaches for directional couplings, and pave the way for promising acoustic devices in the future.

关键词： acoustics near field symmetry

Breaking the barriers: advances in acoustic functional materials

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National Science Review 2018年第2期5卷 159-182页

作者： Hao Ge Min yang Chu Ma Ming-Hui Lu yan-feng chen Nicholas Fang Ping Sheng National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering College of Engineering and Applied SciencesNanjing University Department of Physics Hong Kong University of Science and Technology Department of Mechanical Engineering Massachusetts Institute of Technology Collaborative Innovation Center of Advanced Microstructures Nanjing University

Acoustics is a classical field of study that has witnessed tremendous developments over the past 25 *** by the novel acoustic effects underpinned by phononic crystals with periodic modulation of elastic building blocks in wavelength scale and acoustic metamaterials with localized resonant units in subwavelength scale, researchers in diverse disciplines of physics, mathematics, and engineering have pushed the boundary of possibilities beyond those long held as unbreakable limits. More recently, structure designs guided by the physics of graphene and topological electronic states of matter have further broadened the whole field of acoustic metamaterials by phenomena that reproduce the quantum effects classically. Use of active energy-gain components, directed by the parity–time reversal symmetry principle,has led to some previously unexpected wave characteristics. It is the intention of this review to trace historically these exciting developments, substantiated by brief accounts of the salient milestones. The latter can include, but are not limited to, zero/negative refraction, subwavelength imaging, sound cloaking, total sound absorption, metasurface and phase engineering, Dirac physics and topology-inspired acoustic engineering, non-Hermitian parity–time synthetic active metamaterials, and one-way propagation of sound waves. These developments may underpin the next generation of acoustic materials and devices, and offer new methods for sound manipulation, leading to exciting applications in noise reduction, imaging, sensing and navigation, as well as communications.

关键词： acoustic metamaterials phononic crystals topological acoustics PT-symmetry synthetic acoustics sound absorption

Modified frontolateral partial laryngectomy operation: combined muscle-pedicle hyoid bone and thyrohyoid membrane flap in laryngeal reconstruction

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Cancer Biology & Medicine 2013年第2期10卷 103-109页

作者： Dian Ouyang Tian-Run Liu yan-feng chen Jian Wang Key Laboratory of Oncology in Southern China Department of Head and Neck Sun Yat-sen University Cancer Center Department of Otorinolaryngology Head and Neck Surgery The Sixth Affiliated Hospital of Sun Yat-sen University Department of Anesthesia Sun Yat-Sen University Cancer Center

Objective: Laryngeal reconstruction is needed to preserve laryngeal function in patients who have undergone extensive vertical or frontal partial laryngectomy. However, the procedure remains a difficult challenge. Several reconstruction techniques have been described, but these techniques pose risks of complications such as laryngeal stenosis. This study aimed to evaluate the postoperative course and functional outcomes of a new technique that combined a muscle-pedicle hyoid bone and a thyrohyoid flap during laryngeal reconstruction after tumor resection. Methods: Four patients underwent extensive vertical partial or frontal partial laryngectomy for cancer. After tumor resection, laryngeal reconstruction was performed using the proposed technique. Postoperative recovery time, complications, and oncologic results were evaluated. Results: The four patients were successfully treated with the proposed technique. No dyspnea, dysphagia, or death occurred during the postoperative course. Decannulation was performed after a median of 3 days. The average postoperative hospital stay was 7 days. Short-term postoperative functional recovery was normal. No laryngeal stenosis or tumor recurrence was observed in any of the four patients after a follow-up period of more than 24 months. Conclusion: The combination of the muscle-pedicle hyoid bone and the thyrohyoid flap is a reliable procedure for laryngeal reconstruction after extensive vertical partial or frontal partial laryngectomy.

关键词： Hyoid bone reconstruction laryngeal cancer flap operation

Multi-exit self-distillation with appropriate teachers

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Frontiers of Information Technology & Electronic Engineering 2024年第4期25卷 585-599页

作者： Wujie SUN Defang chen Can WANG Deshi YE yan feng Chun chen College of Computer Science and Technology Zhejiang UniversityHangzhou 310000China

Multi-exit architecture allows early-stop inference to reduce computational cost,which can be used in resource-constrained *** works combine the multi-exit architecture with self-distillation to simultaneously achieve high efficiency and decent performance at different network ***,existing methods mainly transfer knowledge from deep exits or a single ensemble to guide all exits,without considering that inappropriate learning gaps between students and teachers may degrade the model performance,especially in shallow *** address this issue,we propose Multi-exit self-distillation with Appropriate TEachers(MATE)to provide diverse and appropriate teacher knowledge for each *** MATE,multiple ensemble teachers are obtained from all exits with different trainable *** exit subsequently receives knowledge from all teachers,while focusing mainly on its primary teacher to keep an appropriate gap for efficient knowledge *** this way,MATE achieves diversity in knowledge distillation while ensuring learning *** results on CIFAR-100,TinyImageNet,and three fine-grained datasets demonstrate that MATE consistently outperforms state-of-the-art multi-exit self-distillation methods with various network architectures.

关键词： Multi-exit architecture Knowledge distillation Learning gap

Topological boundary states transport in synthetic four-dimensional acoustic system

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Science Bulletin 2022年第19期67卷 1950-1953页

作者： Chudong Xu Taotao Zheng Hao Ge Wei Wang Ze-Guo chen Ming-Hui Lu yan-feng chen College of Electronic Engineering(College of Artificial Intelligence) South China Agricultural UniversityGuangzhou 510642China College of Engineering and Applied Sciences and National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093China Department of Physics Hong Kong Baptist UniversityHong KongChina School of Materials Science and Intelligent Engineering Nanjing UniversitySuzhou 215163China Jiangsu Key Laboratory of Artificial Functional Materials Nanjing 210093China

Topological phase is an important development and unexplored degree of freedom of traditional band theory[1].Generally,it manifests in physics through the boundary states revealed by the bulkedge *** bulk topology implies various low-dimensional states at the boundary,giving extraordinary approaches to manipulate *** structure that encodes the band topology is the system associated with space–time evolution,such as Floquet topological insulator[2,3].Its quasistatic limit involves time-dependent dynamic adiabatic evolution[4,5].However,dynamic evolution is challenging as it requires fast modulation to overcome the dissipation of state before it is pumped from one edge to another[6].An alternative approach is to use an additional degree of freedom to replace the role of time,and an illuminating system is the weakly coupled waveguides,whose governing equation can be directly mapped to Schrodinger equation with time modulation replaced by wave propagation along the ***,such strategy has been largely explored to realize the pumping of topological boundary states in optics[7,8]and elastic wave[9,10].However,the strategy for acoustics is subtly different as the coupling of the acoustic waveguides is not weak for the fundamental waveguide *** exploring the possibility to realize two-dimensional(2D)topological acoustic pumping in a continuous regime remains an open question.

关键词：三维结构人工合成鲁棒性四维声学系统声波导拓扑真实空间

Synthesis and characterization of biodegradable polymer:Poly (ethene maleic acid ester-co-D,L-lactide acid)

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Chinese Chemical Letters 2007年第5期18卷 605-608页

作者： Mei Na Huang yan feng Luo Jia chen Yong Gang Li Chun Hua Fu Yuan Liang Wang Research Center of Bioinspired Material Science and Engineering （BIMSEC） Bioengineering College of Chongqing University Chongqing 400044 China

A novel biodegradable polymer--poly （ethene maleic acid ester-co-D,L-lactide acid） was synthesized by copolymerizing lactide and prepolymer, which was prepared by the condensation of maleic anhydride and glycol, using p-toluene sulphonic acid as a catalyst, attempting to improve the hydrophilicity, increase flexibility and modulate the degradation rate. FTIR,^1H NMR, MALLS and DSC were employed to characterize these polymers.

关键词： Maleic anhydride Glycol Lactide Copolymerization

Scattered Co-anchored MoS_(2)synergistically boosting photothermal capture and storage of phase change materials

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Journal of Energy Chemistry 2024年第8期95卷 208-215,I0005页

作者： yang Li Panpan Liu yan Gao Yuhao feng Peicheng Li Xiao chen Institute of Advanced Materials Beijing Normal UniversityBeijing 100875China School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China School of Environment Beijing Normal UniversityBeijing 100875China

Pristine phase change materials(PCMs)suffer from inherent deficiencies of poor solar absorption and photothermal ***,we proposed a strategy of co-incorporation of zero-dimensional(OD)metal nanoparticles and two-dimensional(2D)photothermal materials in PCMs for efficient capture and conversion of solar energy into thermal *** scattered Co-anchored MoS_(2)nanoflower cluster serving as photon and phonon triggers was prepared by in-situ hydrothermal growth of ZIF67 polyhedron on 2D MoS_(2)and subsequent high-temperature *** encapsulating thermal storage unit(paraffin wax),the obtained composite PCMs integrated high-performance photothermal conversion and thermal energy storage *** from the synergistic enhancement of OD Co nanoparticles with localized surface plasmon resonance effect,carbon layer with the conjugation effect and 2D MoS_(2)with strong solar absorption,composite PCMs exhibited a high photothermal conversion efficiency of 95.19%,Additionally,the resulting composite PCMs also demonstrated long-term thermal sto rage stability and durable structu ral stability after 300 thermal *** proposed collabo rative co-incorporation strategy provides some innovative references for developing next-generation photothermal PCMs in solar energy utilization.

关键词： Phase change materials Photothermal conversion Thermal energy storage