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Correlation of myopia onset and progression with corneal biomechanical parameters in children

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World Journal of Clinical Cases 2022年第5期10卷 1548-1556页

作者： Li-Li Lu Xiao-Juan Hu Yan yang Shen Xu shi-yong yang Cui-Yu Zhang Qing-Ya Zhao Department of Ophthalmology Cangzhou Aier Eye HospitalCangzhou 061000Hebei ProvinceChina

BACKGROUND Recent epidemiological studies have shown that general eye measurement parameters and corneal biomechanical properties can predict the speed of myopic progression in children.AIM To investigate the correlation between the onset and progression of myopia and corneal biomechanical parameters in children.METHODS The study included 102 cases in the emmetropia group,207 cases in the myopic group,and 109 cases in the hyperopic group.The correlation between the change in corneal biomechanical indexes and the change in general ocular measurement parameters was analyzed.A one-way ANOVA test compared general ocular measurement and corneal biomechanical parameters.Pearson’s correlation coefficient was analyzed to correlate corneal biomechanical and general ocular measurement parameters.RESULTS The general ophthalmometric parameters:Spherical equivalent(SE),intraocular pressure(IOP),and axial length(AL),differed significantly among subjects in myopia,emmetropia,and hyperopic groups.Children’s SE positively correlated with corneal biomechanical parameters:Second velocity of applanation(A2V),peak distance(PD),and deformation amplitude(DA)(P<0.05),and second applanation length(A2L)(P<0.05).But it was negatively correlated with PD,DA and integral radius(IR)(P<0.05).Also,IOP was negatively correlated with A2L and IR(P<0.05).AL positively correlated with A2V and negatively correlated with second applanation time(A2T),highest concavity,and PD.Central corneal thickness positively correlated with first applanation length,first applanation time,first applanation deformation amplitude,A2V,A2L,A2T,second applanation deformation amplitude,central curvature radius at highest concavity(HCR),PD,DA,IR,ambrosia relational thickness-horizontal,first applanation stiffness parameter,corvis biomechanical index,topographic and biomechanics index and the first velocity of applanation.The general ocular Km in children positively correlated with corneal biomechanical parameters DA and IR and negatively correlated with A2L,HCR,and PD.There

关键词： Children Myopia Corneal biomechanical parameters Correlation

Improved Properties of Aromatic Polyamide Tape-casting Films

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Chinese Journal of Polymer Science 2020年第12期38卷 1345-1354页

作者： Fu-Lin Liu Jjian-Jun He Hai-Xia yang shi-yong yang Laboratory of Advanced Polymer Materials Institute of ChemistryChinese Academy of SciencesBejing 100190China School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049 China

A convenient tape-casting method was applied to prepare high performance aromatic polyamide(PA)films based on Technora®.During the polycondensation,CaO was introduced to improve the solubility of the PA resin,and the generated halides were totally removed from the film via a simple water bath,without leaving any defects in PA films.The factors of processing temperature and immersion time had been systematically investigated,and the experimental results demonstrated that both of them had impressive impacts on aggregation state and comprehensive properties of the PA film.It was suggested that immersion in water for more than 1 min and baking below 300℃ for 10 min were the optimal conditions for the thermal,tensile,tear,and optical properties to be in the best equilibrium.The resultant PA films integrated outstanding film-forming ability and excellent general performance,especially the tensile property and tear resistance.

关键词： Tape-casting Aromatic polyamide film Solubility Aggregation state Tensile property Tear resistance

The In-plane Orientation and Thermal Mechanical Properties of the Chemically Imidized Polyimide Films

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Chinese Journal of Polymer Science 2019年第3期37卷 268-278页

作者： Zhen-He Wang Xing Chen Hai-Xia yang Jiang Zhao shi-yong yang Laboratory of Advanced Polymer Materials Institute of Chemistry Chinese Academy of Sciences University of Chinese Academy of Science State Key Laboratory of Polymer Physics and Chemistry Institute of Chemistry Chinese Academy of Sciences Department of Polymer Science The University of Akron

The thermal and mechanical properties of the chemically imidized polyimide(CIPI) films and thermally imidized polyimide(TIPI) films were investigated systematically. Experimental results indicated that the CIPI films show dramatically enhanced tensile strength and modulus with obviously reduced coefficient of thermal expansion(CTE) in comparison with TIPI films. These enhancements results from the high in-plane orientation and close packing of the CIPI backbones. Compared with thermal imidization which starts at about 140 °C, the chemical imidization activated by acetic anhydride and isoquinoline initiates the cyclization even at room temperature.The resulting imide rings restrict the mobility of polymer chains and lead to the in-plane orientation with solvent evaporation.Additionally, fewer small molecules remain in the films after treated at 120 °C by chemical imidization than by thermal imidization. The polymer chain plasticization caused by the evaporation of small molecules at high temperature is obviously restricted. Moreover, the partially imidized polymer inhibits the decomposition of mainchains that occurs at subsequent high temperature process, being beneficial to the formation of high molecular weight PI films. Hence, chemical imidization pathway shows apparent advantage to produce PI films with great combined properties, including high modulus, strength and toughness, as well as high thermal dimension stability etc.

关键词： Polyimide film Chemical imidization Thermal imidization In-plane orientation CTE

FLUORENE-BRIDGED POLYPHENYLQUINOXALINES WITH HIGH SOLUBILITY AND GOOD THERMAL STABILITY:SYNTHESIS AND PROPERTIES

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Chinese Journal of Polymer Science 2010年第6期28卷 971-980页

作者： Cheng Li Zhuo Li Jin-gang Liu Hai-xia yang shi-yong yang Laboratory of Advanced Polymer Materials Institute of ChemistryChinese Academy of SciencesBeijing 100190China

A novel fluorene-bridged tetraketone monomer,9,9-bis[(4-benzilyloxy)phenyl]fluorene(FLTK) was synthesized and characterized.The tetraketone was polymerized with various aromatic tetraamines to afford a series of polyphenylquinoxalines(PPQs).The obtained polymers were found to be soluble in common organic solvents such as N-methyl-2-pyrrolidone(NMP),chloroform and m-cresol.Flexible and tough PPQ films obtained by spin-casting their NMP solutions exhibited tensile strengths higher than 60 MPa.The films also demonstrated good thermal stability up to 500℃in nitrogen and glass transition temperatures higher than 280℃.In addition,the PPQ films exhibited good hydrolytic stability. High surface and volume resistivity retentions were achieved for the films after immersion or boiling in water for 24 h.

关键词： Polyphenylquinoxaline Fluorene Solubility Thermal stability Hydrolytic stability

HETEROAROMATIC POLYMERS—HIGH TEMPERATURE POLYPYRROLONES DERIVED FROM 2,6-BIS(3',4'-DIAMINOPHENYL)-4-BIPHENYLPYRIDINE AND VARIOUS AROMATIC DIANHYDRIDES

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Chinese Journal of Polymer Science 2005年第5期23卷 521-529页

作者： Hai-xia yang Jin-gang Liu Xiao-juan Zhao Yan-feng Li Lin Fan shi-yong yang School of Chemistry and Chemical Engineering Lanzhou University Lanzhou 730000 China Laboratory of Advanced Polymer Materials Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

A new type of aromatic tetraarnine containing biphenyl moiety in the side chain was synthesized via a modified Chichibabin＇s reaction. 3-Nitro-4-acetamidoacetophenone was reacted with 4-phenyl benzaldehyde in the presence of ammonium acetate to obtain 2,6-bis（3＇,4＇-diaminophenyl）-4-biphenyl pyridine （DPPA）. A series of polypyrrolones （PPys） were prepared using tetraamine and various aromatic dianhydrides via a two-step cyclization procedure. All the PPys show excellent high temperature stabilities with the initial decomposition temperatures of 530-549℃ and residual weight ratio of 49%-80% at 750℃ in nitrogen. The polymers exhibit no apparent glass transition temperatures （Tgs） except PPy-1 （Tg= 327℃）, which is derived from tetraamine DPPA and 2,2-bis[4-（3＇,4＇-dicarboxyphenoxy）-phenyl]propane dianhydride （BPADA）. In addition, the polymers have acceptable mechanical properties with the tensile strength of 65-94 MPa. The PPy films show excellent hydrolysis-resistance in alkaline aqueous medium and could maintain most of the properties even after boiling in 10% aqueous sodium hydroxide solution for a week.

关键词： Tetraamine Polypyrrolone Pyridine High temperature polymers Film Hydrolysis-resistance.

Novel phosphorus-silicon synergistic flame retardants:Synthesis and characterization

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Chinese Chemical Letters 2012年第7期23卷 793-796页

作者： Tao Song Zhi Sheng Li Jin Gang Liu shi yong yang Laboratory of Advanced Polymer Materials Institute of ChemistryChinese Academy of SciencesBeijing 100190China

Three novel flame retardants containing both phosphorus and silicon elements in their structures,including[（1,1,3,3- tetramethyl-1,3-disiloxanediyl）di-2,1-ethanediyl]bis（diphenylphosphine oxide）（FR-1）,[（2,4,6,8-tetramethylcyclotetra-siloxane -2,4,6,8-tetrayl）tetra-2,1-ethanediyl]tetrakis[diphenylphosphine oxide]（FR-2） and 1,3,5,7,9,11,13,15-octakis（di-phenylphosphine oxide-2,1-ethanediyl）pentacyclo[9.***.1.1^（3,9）.l^（5,15）.1^（7,13）]octasiloxane（FR-3） were synthesized by a convenient pathway from the reaction of diphenylphosphine oxide（DPPO） and vinyl-terminated siloxanes under the catalysis of triethylborane. The chemical structures of the target compounds were confirmed by nuclear magnetic resonance（^1H NMR,^13C NMR,^29Si NMR and ^31P NMR）,matrix-assisted laser desorption/ionization time-of-flight mass spectrometry（MALDI-TOF-MS） and Fourier transform infrared（FT IR） measurements.Thermogravimetric analysis（TGA） results indicated that the new flame retardants possessed good thermal stability both in nitrogen and in air.FR-3 containing polyhedral oligosilsesquioxanes（POSS） moiety exhibited the best thermal properties with a 10%weight loss temperature〉400℃ and a residual weight ratio〉39%at 700℃ .

关键词： Phosphorous-containing siloxanes POSS Flame retardant Synergistic effect

Biogenic volatile organic compounds dominated the near-surface ozone generation in Sichuan Basin,China,during fall and wintertime

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Journal of Environmental Sciences 2024年第7期141卷 215-224页

作者： Dasheng Huang Qing Li Yan Han shi-yong Xia Jiawei Zhou Hanxiong Che Keding Lu Fumo yang Xin Long yang Chen Research Center for Atmospheric Environment Chongqing Institute of Green and Intelligent TechnologyChinese Academy of SciencesChongqing 400714China Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China College of Resources and Environment Chongqing SchoolUniversity of the Chinese Academy of Sciences(UCAS Chongqing)Chongqing 400714China College of Environmental and Chemical Engineering Chongqing Three Gorges UniversityChongqing 404199China Key Laboratory for Urban Habitat Environmental Science and Technology School of Environment and EnergyPeking University Shenzhen Graduate SchoolLishui RoadNanshan DistrictShenzhen 518055China SKL-ESPC and BIC-ESAT College of Environmental Sciences and EngineeringPeking UniversityBeijing 100871China College of Architecture&Environment Sichuan UniversityChengdu 610065China

The complex air pollution driven by both Ozone(O_(3))and fine particulate matter(PM2.5)sig nificantly influences the air quality in the Sichuan Basin(SCB).Understanding the O_(3)for mation during autumn and winter is necessary to understand the atmospheric oxidative capacity.Therefore,continuous in-site field observations were carried out during the late summer,early autumn and winter of 2020 in a rural area of Chongqing.The total volatile organic compounds(VOCs)concentration reported by a Proton-Transfer-Reaction Time-of Flight Mass Spectrometry(PTR-ToF-MS)were 13.66±9.75 ppb,5.50±2.64 ppb,and 9.41±5.11 ppb in late summer,early autumn and winter,respectively.The anthropogenic VOCs(AVOCs)and biogenic VOCs(BVOCs)were 8.48±7.92 ppb and 5.18±2.99 ppb in late sum mer,3.31±1.89 ppb and 2.19±0.93 ppb in autumn,and 6.22±3.99 ppb and 3.20±1.27ppb in winter.A zero-dimensional atmospheric box model was employed to investigate the sensitivity of O_(3)-precursors by relative incremental reactivity(RIR).The RIR values of AV OCs,BVOCs,carbon monoxide(CO),and nitrogen oxides(NOx)were 0.31,0.71,0.09,and-0.36 for late summer,0.24,0.59,0.22,and-0.38 for early autumn,and 0.30,0.64,0.33 and-0.70 for winter,and the results showed that the O_(3)formation of sampling area was in the VOC-limited region,and O_(3)was most sensitive to BVOCs(with highest RIR values,>0.6)This study can be helpful in understanding O_(3)formation and interpreting the secondary formation of aerosols in the winter.

关键词： VOCs PTR-MS Model Ozone

Real-time UAV path planning based on LSTM network

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Journal of Systems Engineering and Electronics 2024年第2期35卷 374-385页

作者： ZHANG Jiandong GUO Yukun ZHENG Lihui yang Qiming shi Guoqing WU yong School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710129China The Flight Automatic Control Research Institute of AVIC Xi’an 710065China Military Representative Office of Marine Wuhan Bureau in Luoyang Area Luoyang 471000China

To address the shortcomings of single-step decision making in the existing deep reinforcement learning based unmanned aerial vehicle(UAV)real-time path planning problem,a real-time UAV path planning algorithm based on long shortterm memory(RPP-LSTM)network is proposed,which combines the memory characteristics of recurrent neural network(RNN)and the deep reinforcement learning algorithm.LSTM networks are used in this algorithm as Q-value networks for the deep Q network(DQN)algorithm,which makes the decision of the Q-value network has some memory.Thanks to LSTM network,the Q-value network can use the previous environmental information and action information which effectively avoids the problem of single-step decision considering only the current environment.Besides,the algorithm proposes a hierarchical reward and punishment function for the specific problem of UAV real-time path planning,so that the UAV can more reasonably perform path planning.Simulation verification shows that compared with the traditional feed-forward neural network(FNN)based UAV autonomous path planning algorithm,the RPP-LSTM proposed in this paper can adapt to more complex environments and has significantly improved robustness and accuracy when performing UAV real-time path planning.

关键词： deep Q network path planning neural network unmanned aerial vehicle(UAV) long short-term memory(LSTM)

Loyal wingman task execution for future aerial combat:A hierarchical prior-based reinforcement learning approach

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Chinese Journal of Aeronautics 2024年第5期37卷 462-481页

作者： Jiandong ZHANG Dinghan WANG Qiming yang Zhuoyong shi Longmeng JI Guoqing shi yong WU School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710129China

In modern Beyond-Visual-Range(BVR)aerial combat,unmanned loyal wingmen are pivotal,yet their autonomous capabilities are limited.Our study introduces an advanced control algorithm based on hierarchical reinforcement learning to enhance these capabilities for critical missions like target search,positioning,and relay guidance.Structured on a dual-layer model,the algorithm’s lower layer manages basic aircraft maneuvers for optimal flight,while the upper layer processes battlefield dynamics,issuing precise navigational commands.This approach enables accurate navigation and effective reconnaissance for lead aircraft.Notably,our Hierarchical Prior-augmented Proximal Policy Optimization(HPE-PPO)algorithm employs a prior-based training,prior-free execution method,accelerating target positioning training and ensuring robust target reacquisition.This paper also improves missile relay guidance and promotes the effective guidance.By integrating this system with a human-piloted lead aircraft,this paper proposes a potent solution for cooperative aerial warfare.Rigorous experiments demonstrate enhanced survivability and efficiency of loyal wingmen,marking a significant contribution to Unmanned Aerial Vehicles(UAV)formation control research.This advancement is poised to drive substantial interest and progress in the related technological fields.

关键词： Beyond-visual-range Loyal wingmen Hierarchical prior-augmented proximal policy optimization Unmanned aerial vehicles Warfare