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Tailoring sulfur-doped and nitrogen-defective carbon nitride nanosheets for efficient photo-controlled radical polymerizations

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Science China Chemistry 2024年第7期67卷 2325-2334页

作者： Xue Li Meng kai Xu Yuan Huang Tao Cai Key Laboratory of Biomedical Polymers of Ministry of Education College of Chemistry and Molecular SciencesWuhan UniversityWuhan 430072China Wuhan University Shenzhen Research Institute Shenzhen 518057China

Despite the challenges that remain,the synergistic adjustment of various microstructures and photochemical parameters of graphitic carbon nitride(g-C_(3)N_(4))in photocatalytic reactions holds promises for improving catalytic efficiency and reducing energy ***,sulfur-doped and nitrogen-defective g-C_(3)N_(4)(n-SC_(3)N_(x))nanosheets were designed and elaborately *** resultant n-SC_(3)N_(x)possessed a precisely defined 2D layer structure with extensive porosity and incremental specific surface *** photoinduced electron transfer-reversible addition-fragmentation chain transfer(PET-RAFT)polymerization of vinyl monomers with low dispersity,excellent temporal control and high chain-end fidelity was achieved under mild blue light irradiation in a nondegassed *** to their ultrathin nanostructures with nitrogen defects and sulfur dopants,n-SC_(3)N_(x)was capable of catalyzing RAFT polymerization in aqueous solutions at significantly accelerated rates,which were nearly 8 times faster compared to bulk g-C_(3)N_(4).The ease of separation and efficient reusability in subsequent polymerizations was enabled by the heterogeneous nature of n-SC_(3)N_(x).The appeal of this approach was illustrated by the fact that utilizing a reusable and metal-free photocatalyst in aqueous environments allowed for the synthesis of polymers with molecular weight up to 300 kg mol^(-1) and a dispersity of 1.32.

关键词： graphitic carbon nitride nitrogen defects sulfur dopants PET-RAFT polymerization recyclability

Icariin attenuates vascular endothelial dysfunction by inhibiting inflammation through gPER/Sirt1/HMgB1 signaling pathway in type 1 diabetic rats

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Chinese Journal of Natural Medicines 2024年第4期22卷 293-306页

作者： YAO Wenhui TAO Rongpin WANg kai DINg Xuansheng School of Basic Medicine and Clinical Pharmacy China Pharmaceutical UniversityNanjing211198China

Icariin, a flavonoid glycoside, is extracted from Epimedium. This study aimed to investigate the vascular protective effects of icariin in type 1 diabetic rats by inhibiting high-mobility group box 1 (HMgB1)-related inflammation and exploring its potential mechanisms. The impact of icariin on vascular dysfunction was assessed in streptozotocin (STZ)-induced diabetic rats through vascular reactivity studies. Western blotting and immunofluorescence assays were performed to measure the expressions of target proteins. The release of HMgB1 and pro-inflammation cytokines were measured by enzyme-linked immunosorbent assay (ELISA). The results revealed that icariin administration enhanced acetylcholine-induced vasodilation in the aortas of diabetic rats. It also notably reduced the release of pro-inflammatory cytokines, including interleukin-8 (IL-8), IL-6, IL-1β, and tumor necrosis factor-alpha (TNF-α) in diabetic rats and high glucose (Hg)-induced human umbilical vein endothelial cells (HUVECs). The results also unveiled that the pro-inflammatory cytokines in the culture medium of HUVECs could be increased by rHMgB1. The increased release of HMgB1 and upregulated expressions of HMgB1-related inflammatory factors, including advanced glycation end products (RAgE), Toll-like receptor 4 (TLR4), and phosphorylated p65 (p-p65) in diabetic rats and Hg-induced HUVECs, were remarkably suppressed by icariin. Notably, HMgB1 translocation from the nucleus to the cytoplasm in HUVECs under Hg was inhibited by icariin. Meanwhile, icariin could activate g protein-coupled estrogen receptor (gPER) and sirt1. To explore the role of gPER and Sirt1 in the inhibitory effect of icariin on HMgB1 release and HMgB-induced inflammation, gPER inhibitor and Sirt1 inhibitor were used in this study. These inhibitors diminished the effects of icariin on HMgB1 release and HMgB1-induced inflammation. Specifically, the gPER inhibitor also negated the activation of Sirt1 by icariin. These findings suggest t

关键词： Icariin Diabetes Inflammation Vascular endothelial dysfunction gPER HMgB1

Design of a Bio-inspired,Two-winged,Flapping-wing Micro Air Vehicle with High-lift Performance

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Journal of Bionic Engineering 2024年第3期21卷 1191-1207页

作者： kai Hu Huichao Deng Shengjie Xiao gongyu Yang Yuhong Sun Space Robot Laboratory The School of Mechanical EngineeringBeihang UniversityBeijing100191China

In this paper,we present the development of our latest flapping-wing micro air vehicle(FW-MAV),named Explobird,which features two wings with a wingspan of 195 mm and weighs a mere 25.2 g,enabling it to accomplish vertical take-off and hover *** devised a novel gear-based mechanism for the flapping system to achieve high lift capability and reliability and conducted extensive testing and analysis on the wings to optimise power matching and lift *** Explobird can deliver a peak lift-to-weight ratio of 1.472 and an endurance time of 259 s during hover flight powered by a single-cell LiPo *** the inherent instability of the prototype,we discuss the derivatives of its longitudinal system,underscoring the importance of feedback control,position of the centre of gravity,and increased *** demonstrate the effect of damping enhancement on stability,we also designed a passive stable ***,the vehicle is actively stabilised in roll by adjusting the wing root bars and in pitch through high-authority tail control,whereas yaw is passively *** a series of flight tests,we successfully demonstrate that our prototype can perform vertical take-off and hover flight under wireless *** promising results position the Explobird as a robust vehicle with high lift capability,paving the way towards the use of FW-MAVs for carrying load equipment in multiple tasks.

关键词： Flapping wing Biologically inspired robots Mechanical design Flight dynamics Damping enhancement

Atomic-level unveiling secondary recrystallization enabled microand macroscopic polarization enhancement for piezophotocatalytic oxygen activation

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Nano Research 2024年第6期17卷 5040-5049页

作者： kai Lin Zijian Zhu Weiyi ge Tianxing Jiang Hongwei Huang Engineering Research Center of Ministry of Education for geological Carbon Storage and Low Carbon Utilization of Resources Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid WastesNational Laboratory of Mineral MaterialsSchool of Material Sciences and TechnologyChina University of Geosciences(Beijing)Beijing 100083China School of Chemistry Beihang UniversityBeijing 100191China

Piezoelectric semiconductors bear the bifunctional photocatalysis and piezocatalysis,while the absent or weak internal cha.ge driving force severely restricts its catalytic *** polarization strategy is desirable,and particularly understanding its mechanism from a microscopic perspective remains ***,we report a secondary recrystallization approach to achieving the simultaneous micro-and macroscopic polarization enhancement on Bi2WO6 nanosheets for boosting piezo-photocatalytic oxygen activation,and unravel the mechanism at an *** secondary recrystallization process not only results in a strengthened distortion of[WO6]octahedra with distortion index enhancement by~20%for a single octahedron,but also enables lateral crystal growth of nanosheets along the ab plane(av.50 to 180 nm),which separately allows the rise in dipole moment of unit cell(e.g.,1.63 D increase along a axis)and the stacking of the distorted[WO6]octahedron to accumulate the unit cell dipole,collectively contributing to the considerably strengthened spontaneous polarization and ***,exposure of large-area{001}front facet enables more efficient capture and conversion of stress into ***,the well-recrystallized Bi2WO6 nanosheets exhibit considerably promoted piezo-photocatalytic reactive oxygen species generation,given the decreased specific surface *** work presents a feasible methodology to regulate inside-out polarization for guiding carriers transfer behavior,and may advance the solid understanding on the intrinsic mechanism.

关键词： secondary recrystallization piezo-photocatalytic oxygen activation octahedron distortion polar units stacking micro-and macroscopic polarization enhancement

Design of quasi-zero-stiffness elastic diodes for low-frequency nonreciprocity through machine learning

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Acta Mechanica Sinica 2024年第7期40卷 137-151页

作者： Junsen He Jiaxi Zhou kai Wang Qiang Wang College of Mechanical and Vehicle Engineering Hunan UniversityChangsha 410082China Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle Hunan UniversityChangsha 410082China Department of Mechanical Engineering Hong Kong Polytechnic UniversityHong KongChina

Elastic diodes with nonreciprocity have the potential to enable unidirectional modulation of elastic ***,it is a challenge to achieve nonreciprocity at low frequencies(<100 Hz)using existing elastic *** paper proposes... 详细信息

Elastic diodes with nonreciprocity have the potential to enable unidirectional modulation of elastic ***,it is a challenge to achieve nonreciprocity at low frequencies(g existing elastic *** paper proposes a quasizero-stiffness(QZS)elastic diode to resolve such a tough issue and fulfill high-quality low-frequency *** proposed elastic diode is invented by combining a QZS locally resonant metamaterial with a linear one,where the beneficial nonlinearity of the QZS metamaterial facilitates opening an amplitude-dependent band gap at very low ***,the dispersion relation of the QZS metamaterial is derived theoretically based on the harmonic balance method(HBM).Then,the transmissibility of the QZS elastic diode in both the forward and backward directions is calculated through theoretical analyses and numerical ***,the influences of system parameters on the low-frequency nonreciprocal effect are *** results indicate that considerable nonreciprocity is observed at a quite low frequency(e.g.,9 Hz),which is achieved by amplitude-dependent local resonance combined with interface ***,a machine learning-based design optimization is introduced to evaluate and enhance the nonreciprocal effect of the QZS elastic *** the aid of machine learning(ML),the computational cost of predicting nonreciprocal effects during design optimization can be significantly *** design optimization,the nonreciprocal frequency bandwidth can be broadened while maintaining considerable isolation quality at low frequencies.

关键词： Nonreciprocity Low-frequency Elastic diode Quasi-zero-stiffness Nonlinear elastic metamaterials Machine learning

Efflcient machining of a complex blisk channel using a disc cutter

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Chinese Journal of Aeronautics 2024年第1期37卷 414-437页

作者： Xiangyu LI Zhaoyu LI Dong HE Junxue REN Qian FENg kai TANg Department of Mechanical and Aerospace Engineering Hong Kong University of Science and TechnologyHong Kong 999077China Key Laboratory of High Performance Manufacturing for Aero Engine(Northwestern Polytechnical University) Ministry of Industry and Information TechnologyXi’an 710072China Xi’an Sanhang Power Technology Co. LtdXi’an 710000China HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute FutianShenzhen 518057China HKUST Shenzhen Research Institute Shenzhen 518057China

For rough machining of a complex narrow cavity,e.g.,a complex blisk channel on an aero-engine,the typically used cutting tools are the slender cylindrical cutter and conical ***,as neither of the two is particularly suited for rough machining,wherein the main purpose is to remove a large volume as quickly as possible,the machining efficiency is low,especially when the part materials are of hard-to-cut types(e.g.,Titanium-alloy)for which it often takes days to rough machine a ***,disc machining provides a new and efficient roughing solution,since a disc cutter with a large radius enables a much larger cutting speed and thus a larger material removal ***,due to the large radius of the disc cutter,its potential collision with narrow and twisted channels becomes a serious *** this paper,we propose a novel twophase approach for efficiently machining a complex narrow cavity workpiece using a disc-shaped cutter,i.e.,3+2-axis disc-slotting of the channel by multiple layers(rough machining)+five-axis disc-milling of the freeform channel side surfaces(semi-finish machining).Both simulation and physical cutting experiments are conducted to assess the effectiveness and advantages of the proposed *** experimental results show that,with respect to a same cusp-height threshold on the channel side surfaces,the total machining time of the tested part by the proposed method is about only 36%of that by the conventional approach of plunging-milling(for roughing)plus milling by a slender cylindrical cutter(for semi-finishing).

关键词： Blisk channel CNC machining Disc cutter Roughing efficiency Tool path planning

Nondestructive and active interrogation system for special nuclear material:proof of principle and initial results

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Nuclear Science and Techniques 2024年第5期35卷 216-225页

作者： Mahmoud Bakr kai Masuda Yoshiyuki Takahashi Tsuyoshi Misawa Norio Yamakawa Tomas Scott Institute of Advanced Energy Kyoto UniversityGokashoUjiKyoto 611‑0011Japan School of Physics University of BristolBs81TL Tyndall AvenueBristolUK Physics Department Faculty of ScienceAssiut UniversityAssiut 71516Egypt Research Reactor Institute Kyoto University2 Asashiro‑NishiKumatoriOsaka 590‑0494Japan Pony Industry Co.Ltd. 2‑3‑6 Kitakyuhoji‑MachiChuo‑KuOsaka 541‑0057Japan Astral Neutronics LTD Unit H5HallenBristol BS107SBUK

Herein,we employ the threshold energy neutron analysis(TENA)technique to introduce the world's first active interrogation system to detect special nuclear materials(SNMs),including U-235 and *** system utilizes a DD neutron generator based on inertial electrostatic confinement(IEC)to interrogate suspicious *** detect secondary neutrons produced during fission reactions induced in SNMs,a tensioned metastable fluid detector(TMFD)is *** current status of the system's development is reported in this paper,accompanied by the results from experiments conducted to detect 10 g of highly enriched uranium(HEU).Notably,the experimental findings demonstrate a distinct difference in the count rates of measurements with and without *** difference in count rates surpasses two times the standard deviation,indicating a confidence level of more than 96% for identifying the presence of *** paper presents and extensively discusses the proof-of-principle experimental results,along with the system's planned trajectory.

关键词： Special nuclear materials Uranium detection Inertial electrostatic confinement fusion TENA HEU CTMFD

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流体喷管对脉冲爆震发动机推进性能的影响

航空动力学报 2024年第2期39卷 47-56页

作者：门凯邱华严宇熊姹陈山山西北工业大学动力与能源学院西安710129 西安航天动力研究所热过程重点实验室西安710100

为了进一步提高脉冲爆震发动机(PDE)的推进性能,对PDE使用流体喷管模型进行了多循环数值模拟研究,并提出了主次流错相位喷注方案。结果表明:主次流错相位喷注方案不仅可以调节主流和二次流的有效流通面积,改善喷管的非设计点状态,而且... 详细信息

为了进一步提高脉冲爆震发动机(PDE)的推进性能,对PDE使用流体喷管模型进行了多循环数值模拟研究,并提出了主次流错相位喷注方案。结果表明:主次流错相位喷注方案不仅可以调节主流和二次流的有效流通面积,改善喷管的非设计点状态,而且可以提高爆震室内可燃气最终充填压力,增强爆震燃烧强度;在主次流错相位喷注方案下,喷管主流进口瞬时气流总压相对喷管设计点的离散程度明显下降,有效改善了喷管的非设计点状态;最佳的主次流相位差为反传压缩波恰好传播至爆震室头部这一工况,最佳的二次流喷注位置为喷管喉部;相比基准喷管的最大比冲性能,PDE使用流体喷管可以产生5.64%的比冲增益。

关键词：脉冲爆震发动机喷管二次流内流分析推进性能

Synergism of preintercalated manganese ions and lattice water in vanadium oxide cathodes for high-capacity and long-life Zn-ion batteries

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Journal of Energy Chemistry 2024年第9期96卷 709-717页

作者： Mengjing Wu Rongrong Li kai Yang Lijiang Yin Weikang Hu Xiong Pu Key Laboratory of the Ministry of Education for Advanced Catalysis Material Institute of Physical ChemistryCollege of Chemistry and Materials ScienceZhejiang Normal UniversityJinhua 321004ZhejiangChina CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 101400China School of Nanoscience and Engineering University of Chinese Academy of SciencesBeijing 100049China Chilwee Power Co.Ltd. Changxing 313100ZhejiangChina

Aqueous Zn-ion batteries(AZIBs)are recognized as a promising energy storage system with intrinsic safety and low cost,but its applications still rely on the design of high-capacity and stable-cycling cathode *** this work,we present an intercalation mechanism-based cathode materials for AZIB,*** vanadium oxide with pre-intercalated manganese ions and lattice water(noted as MVOH).The synergistic effect between Mn^(2+)and lattice H_(2)O not only expands the interlayer spacing,but also significantly enhances the structural *** in-situ and ex-situ characterizations clarify the Zn^(2+)/H^(+)co–(de)intercalation mechanism of MVOH in aqueous *** demonstrated remarkable structure stability,excellent kinetic behaviors and ion-storage mechanism together enable the MVOH to demonstrate satisfactory specific capacity of 450 mA h g^(−1)at 0.2 A g^(−1),excellent rate performance of 288.8 mA h g^(−1)at 10 A g^(−1)and long cycle life over 20,000 cycles at 5 A g^(−1).This work provides a practical cathode material,and contributes to the understanding of the ion-intercalation mechanism and structural evolution of the vanadium-based cathode for AZIBs.

关键词： Zn-ion batteries Vanadium oxide Pre-intercalation Lattice water Manganese ion