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Leakage and Stiffness Characteristics of Bionic Cluster Spiral Groove Dry Gas Seal

Chinese Journal of Mechanical Engineering 2018年第2期31卷 148-158页

作者： Jin-Bo Jiang Xu-Dong peng Ji-yun li Yuan Chen Engineering Research Center of Process Equipment and Its Re-manufacturing of Ministry of Education Zhejiang University of Technology

Spiral groove dry gas seal(S?DGS), the most widely used DGS in the world, encounters the problem of high leakage rate and inferior film stability when used in high?speed machinery equipment, which could not be well solved by optimization of geometrical parameters and molded line of spiral groove. A new type of bionic cluster spiral groove DGS(CS?DGS) is proved to have superior film stability than S?DGS at the condition of high?speed and low?pressure numerically. A bionic CS?DGS is experimentally investigated and compared with common S?DGS in order to provide evidence for theoretical study. The film thickness and leakage rate of both bionic spiral groove and common spiral groove DGS are measured and compared with each other and with theoretical values under different closing force at the condition of static pressure, high?speed and low?pressure, and the film stiffness and stiffness?leakage ratio of these two face seals are derived by the relationship between closing force and film thickness at the steady state. Experimental results agree well with the theory that the leakage and stiffness of bionic CS?DGS are superior to that of common S?DGS under the condition of high?speed and low?pressure, with the decreasing amplitude of 20% to 40% and the growth amplitude of 20%, respectively. The opening performance and stiffness characteristics of bionic CS?DGS are inferior to that of common S?DGS when rotation speed equals to 0 r/min. The proposed research provides a new method to measure the axis film stiffness of DGS, and validates the superior performance of bionic CS?DGS at the condition of high?speed and low?pressure experimentally.

关键词： Bionic cluster spiral groove Film stiffness Dry gas seal Leakage rate

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Highly Efficient Random Terpolymers for Photovoltaic Applications with Enhanced Absorption and Molecular Aggregation

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Chinese Journal of Polymer Science 2017年第2期35卷 249-260页

作者： Xiao-peng Xu Guang-jun Zhang yun-zhe Zhao 刘江 Ying li 彭强 Key Laboratory of Green Chemistry and Technology of Ministry of Education College of ChemistryState Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610064China Chengdu Green Energy and Green Manufacturing Technology R&D Center Chengdu 610207China

A series of copolymers, based on benzo[1,2-b：4,5-b＇]dithiophene （BDT） as the electron donor and 2,1,3- benzothiadiazole （BT）/diketopyrrolo[3,4-c]pyrrole （DPP） as the electron acceptors, were synthesized for highly efficient polymer solar cells. By changing the BT/DPP ratio in the conjugated backbone, the absorption, energy levels, molecular aggregation and carrier mobility could be finely tuned. With increased DPP content, the absorption range was extended to the longer wavelength region with narrower bandgaps. The highest occupied molecular orbital （HOMO） levels were also raised up and the molecular aggregation was enhanced. The balance of these factors would afford a remarkable device performance enhancement. Polymer P3 with BT：DPP = 0.7：0.3 （molar ratio） exhibited the highest power conversion efficiency （PCE） of 9.01%, with open circuit voltage （Voc） = 0.73 V, short current density （Jsc） = 18.45 ***-2, and fill factor （FF） - 66.9%. The PCE value was improved by 48.7% compared to P1 and by 117.6% compared to P7, respectively, indicating a great potential in photovoltaic application.

关键词： Polymer solar cells Terpolymers Complementary absorption Molecular aggregation

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Study on Robust H_∞ Filtering in Networked Environments

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International Journal of Automation and computing 2011年第4期8卷 465-471页

作者： yun-ze Cai li Xu Jian-Xi Gao Xiao-Ming Xu Department of Automation Shanghai Jiao Tong University Shanghai 200240 PRC Shanghai Academy of Systems Science Shanghai 200093 PRC Department of Electronics and Information Systems Akita Prefectural University Yuri-Honjo Akita 015 0055 Japan University of Shanghai for Science and Technology Shanghai 200093 PRC

This paper is concerned with the robust H ∞ filter problem for networked environments, which are subject to both transmission delay and packet dropouts randomly. By employing random series which have Bernoulli distributions taking value of 0 or 1, the data transmission model is obtained. Based on state augmentation and stochastic theory, the sufficient condition for robust stability with H ∞ constraints is derived for the filtering error system. The robust filter is designed in terms of feasibility of one certain linear matrix inequality （LMI）, which is formed by adopting matrix congruence transformations. A numerical example is given to show the effectiveness of the proposed filtering method.

关键词： Robust filtering networked environments transmission delay packet dropouts linear matrix inequality (LMI).

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Exploring the Antarctic sky:Dome A’s astronomical endeavors in 2024 and beyond

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The Innovation 2024年第4期5卷 1-2页

作者： Zhengyang li yun li peng Jiang Nanjing Institute of Astronomical Optics&Technology Chinese Academy of ScienceNanjing 210042China CAS Key Laboratory of Astronomical Optics&Technology Nanjing Institute of Astronomical Optics&TechnologyNanjing 210042China Polar Research Institute of China Shanghai 200136China Key Laboratory for Polar Science MNRPolar Research Institute of ChinaShanghai 200136China

OVERVIEW OF CHINA’S 40TH ANTARCTIC EXPEDITION ON *** February 17,2024,four astronomers from the Chinese 40th Antarctic Scientific Research Expedition(CHINARE)team returned to China via Antarctic aviation after successfully completing a 100-day scientific *** is the 12th expedition to Dome A since the team’s decision to conduct astronomical observations on the Antarctic Plateau in *** at the summit of the Antarctic continent,Dome A is regarded as Earth’s premier astronomical *** this expedition,the team installed an infrared telescope,a low-frequency radio detector,and a terahertz *** also conducted repairs on the previously installed optical telescope(the second Antarctic Survey Telescope AST3-2).The successful operation of these advanced instruments marked a significant milestone for Chinese Antarctic astronomy,symbolizing the commencement of the next exploration phase(Figure 1).

关键词： Antarctic Dome astronomical

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Fine Root Patterning and Balanced Inorganic Phosphorus Distribution in the Soil Indicate Distinctive Adaptation of Maize Plants to Phosphorus Deficiency

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Pedosphere 2012年第6期22卷 870-877页

作者： ZHANG Yu YU peng peng yun-Feng li Xue-Xiun CHEN Fan-Jun li Chun-Jian Key Laboratory of Plant-Soil Interactions Ministry of EducationDepartment of Plant NutritionChina Agricultural UniversityBeijing 100193(China)

Plants have diverse strategies to cope with phosphorus （P） deficiency. To better understand how maize responds to P deficiency, a field experiment with two P levels, 0 and 100 kg P205 ha-1 （P0 and P100, respectively）, was carried out as a part of a long-term Pfertilizer field trial. Plant and soil analyses showed that P-deficient maize reduced its growth rate, increased P use efficiency, and formed more thin roots with the diameter less than 0.6 mm at jointing and silking stages, compared to the plants treated with P100. Further, there were no differences in major inorganic P fractions （Ca2-P, Cas-P, Al-P, Fe-P, occluded P and Ca10-P） between the rhizospheric and bulk soils at each harvest, even when soil Olsen-P was only 1.38 mg kg-1. These results suggested that maize responded to P deficiency by reducing the internal P demand for growth and increasing P acquisition ability by favorable root morphological alteration at low carbon cost.

关键词： inorganic phosphorus fractions phosphorus starvation rhizosphere root length root morphology

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Ultra-broadband reflectionless Brewster absorber protected by reciprocity

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light(Science & Applications) 2021年第5期10卷 931-940页

作者： Jie Luo Hongchen Chu Ruwen peng Mu Wang Jensen li yun Lai School of Physical Science and Technology Soochow UniversitySuzhou215006China National Laboratory of Solid State Microstructures School of Physicsand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing210093China Department of Physics The Hong Kong University of Science and TechnologyClear Water BayHong KongChina William Mong Institute of Nano Science and Technology The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina

The Brewster’s law predicts zero reflection of p-polarization on a dielectric surface at a particular ***,when loss is introduced into the permittivity of the dielectric,the Brewster condition breaks down and reflection unavoidably *** this work,we found an exception to this long-standing dilemma by creating a class of nonmagnetic anisotropic metamaterials,where anomalous Brewster effects with independently tunable absorption and refraction *** loss-independent Brewster effect is bestowed by the extra degrees of freedoms introduced by anisotropy and strictly protected by the reciprocity *** bandwidth can cover an extremely wide spectrum from dc to optical *** examples of reflectionless Brewster absorbers with different Brewster angles are both demonstrated to achieve large absorbance in a wide spectrum via microwave *** work extends the scope of Brewster effect to the horizon of nonmagnetic absorptive materials,which promises an unprecedented wide bandwidth for reflectionless absorption with high efficiency.

关键词： polarization absorber dielectric

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High mass loading NiCo_(2)O_(4) with shell-nanosheet/core-nanocage hierarchical structure for high-rate solid-state hybrid supercapacitors

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Green Energy & Environment 2022年第4期7卷 723-733页

作者： Wang Yang liqiang Hou peng Wang yun li Rui li Bo Jiang Fan Yang Yongfeng li State Key Laboratory of Heavy Oil Processing China University of Petroleum(Beijing)Changping102249China

Rational design of advanced structure for transition metal oxides(TMOs) is attractive for achieving high-performance ***, it is hampered by sluggish reaction kinetics, low mass loading, and volume change upon cycling. Herein, hierarchical Ni Co_(2)O_(4) architectures with 2D-nanosheets-shell and 3D-nanocages-core(2D/3D h-NCO) are directly assembled on nickel foam via a facile one-step *** 2D nanosheets are in-situ generated from the self-evolution of initial NCO nanospheres. This 2D/3D hierarchical structures ensure fast ion/electron transport and maintain the structural integrity to buffer the volume expansion. The 2D/3D h-NCO electrode with an ultrahigh mass loading(30 mg cm^(-2)) achieves a high areal capacity of 4.65 C cm^(-2)(equivalent to 1.29 mAh cm^(-2)) at a current density of 4 mA cm^(-2), and retains 3.7 C cm^(-2) even at 50 mA cm^(-2). Furthermore, the assembled solid-state hybrid supercapacitor yields a high volumetric energy density of 4.25 mWh cm^(-3) at a power density of 39.3 mW cm^(-3), with a high capacity retention of 92.4% after 5000 cycles. Therefore, this work provides a new insight to constuct hierarchical electrodes for energy storage application.

关键词： Transition-metal oxides Hierarchical structure High mass loading Free-standing Supercapacitors

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The formation of crystalline lithium sulfide on electrocatalytic surfaces in lithium-sulfur batteries

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Journal of Energy Chemistry 2022年第1期31卷 568-573,I0015页

作者： yun-Wei Song Jin-Lei Qin Chang-Xin Zhao Meng Zhao li-peng Hou Yan-Qi peng Hong-Jie peng Bo-Quan li Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology Department of Chemical EngineeringTsinghua UniversityBeijing 100084China Advanced Research Institute of Multidisciplinary Science Beijing Institute of TechnologyBeijing 100081China Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengduSichuan 611731China

lithium-sulfur(li-S)battery is highly regarded as a promising next-generation energy storage device but suffers from sluggish sulfur redox *** the behavior and mechanism of the sulfur species on electrocatalytic surface is the first step to rationally introduce polysulfide electrocatalysts for kinetic promotion in a working ***,crystalline lithium sulfide(li_(2)S)is exclusively observed on electrocatalytic surface with uniform spherical morphology while li_(2)S on non-electrocatalytic surface is amorphous and *** characterization indicates the crystalline li_(2)S preferentially participates in the discharge/charge process to render reduced interfacial resistance,high sulfur utilization,and activated sulfur redox ***,crystalline li_(2)S is proposed with thermodynamic and kinetic advantages to rati on alize the superior performances of li-S *** evoluti on of solid li_(2)S on electrocatalytic surface not only addresses the polysulfide electrocatalysis strategy,but also inspires further investigation into the chemistry of energy-related processes.

关键词： lithium-sulfur batteries Polysulfide electrocatalysis lithium sulfide Framework porphyrin Sulfur redox reactions

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Tailoring chaotic motion of microcavity photons in ray and wave dynamics by tuning the curvature of space

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 107-112页

作者： Wei lin Yechun Ding Yongsheng Wang peng li Yanpeng Zhang Feng yun Feng li Key Laboratory for Physical Electronics and Devices of the Ministry of Education Shaanxi Key Lab of Information Photonic TechniqueSchool of Electronic Science and EngineeringFaculty of Electronic and Information EngineeringXi’an Jiaotong UniversityXi’an 710049China Department of Electrical and Photonics Engineering Technical University of DenmarkKgs.Lyngby 2800Denmark Center for Regenerative and Reconstructive Medicine Med-X InstituteThe First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710061China Solid-State lighting Engineering Research Center Xi’an Jiaotong UniversityXi’an 710049China

Microcavity photon dynamics in curved space is an emerging interesting area at the crossing point of nanophotonics,chaotic science,and non-Euclidean *** report the sharp difference between the regular and chaotic motions of cavity photons subjected to the varying space *** the island modes of regular motion rise in the phase diagram in the curved space,the chaotic modes show special mechanisms to adapt to the space curvature,including the fast diffusion of ray dynamics,and the localization and hybridization of the Husimi wavepackets among different periodic *** observations are unique effects enabled by the combination of the chaotic trajectory,the wave nature of light,and the non-Euclidean orbital motion,and therefore make the system a versatile optical simulator for chaotic science under quantum mechanics in curved space-time.

关键词： microcavity chaotic motion curved space

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产业匹配视角下的环京产研一体化圈建设策略

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河北学刊 2025年第1期45卷 82-90页

作者：张可云黎思灏中国人民大学应用经济学院

打造环京产研一体化圈层是推动京津冀协同发展的创新举措,需要推动北京市制造业高新技术企业与环京区县的合作。但环京区县存在产业基础薄弱、与北京产业匹配度不高和产业投资联系不强的问题。两地发展差距过大、市郊铁路建设滞后和环... 详细信息

打造环京产研一体化圈层是推动京津冀协同发展的创新举措,需要推动北京市制造业高新技术企业与环京区县的合作。但环京区县存在产业基础薄弱、与北京产业匹配度不高和产业投资联系不强的问题。两地发展差距过大、市郊铁路建设滞后和环京区县营商环境不良是造成上述问题的主要原因。未来应当根据产业匹配度建立对口合作关系,进一步加强市际交通基础设施建设,降低企业营商成本。

关键词：京津冀环京区县产研一体高新技术企业上市公司异地投资

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