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Research on the Encapsulation Device for Lunar Samples

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 104-117页

作者： Yonggang Du Chunyong Wang Haoling Li Ying Zhou Ming Ji Xuesong Wang lanzhou Institute of Physics CASTLanzhou 730000China

The encapsulation of lunar samples is a core research area in the third phase of the Chinese Lunar Exploration *** seal assembly,opening and closing mechanism(OCM),and locking mechanism are the core components of the encapsulation device of the lunar samples,and the requirements of a tight seal,lightweight,and low power make the design of these core components *** this study,a combined sealing assembly,OCM,and locking mechanism were investigated for the *** sealing architecture consists of rubber and an Ag-In alloy,and a theory was built to analyze the *** of the electroplate Au coating on the knife-edge revealed that the hermetic seal can be significantly *** driving principle for coaxial double-helical pairs was investigated and used to design the ***,a locking mechanism was created using an electric initiating explosive device with orifice *** optimizing the design,the output parameters were adjusted to meet the requirements of the lunar *** experimental results showed that the helium leak rate of the test pieces were not more than 5×10^(-11) Pa·m^(3)·s^(-1),the minimum power of the OCM was 0.3 W,and the total weight of the principle prototype was 2.9 *** explosive driven locking mechanism has low *** investigation solved the difficulties in achieving tight seal,light weight,and low power for the lunar explorer,and the results can also be used to explore other extraterrestrial objects in the future.

关键词： Lunar samples Encapsulation Vacuum seal Mechanism

Effect of external magnetic field on the instability of THz plasma waves in nanoscale graphene field-effect transistors

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Chinese Physics B 2024年第4期33卷 683-689页

作者：张丽萍孙宗耀李佳妮苏俊燕 School of Sciences Lanzhou University of TechnologyLanzhou 730050China

The instability of plasma waves in the channel of field-effect transistors will cause the electromagnetic waves with THz *** on a self-consistent quantum hydrodynamic model,the instability of THz plasmas waves in the channel of graphene field-effect transistors has been investigated with external magnetic field and quantum *** analyzed the influence of weak magnetic fields,quantum effects,device size,and temperature on the instability of plasma waves under asymmetric boundary conditions *** results show that the magnetic fields,quantum effects,and the thickness of the dielectric layer between the gate and the channel can increase the radiation ***,we observed that increase in temperature leads to a decrease in both oscillation frequency and instability *** numerical results and accompanying images obtained from our simulations provide support for the above conclusions.

关键词： graphene field-effect transistors external magnetic field radiation frequency instability increment

Effects of individual heterogeneity on social contagions

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Chinese Physics B 2024年第5期33卷 737-747页

作者：年福忠杨宇 School of Computer and Communication Lanzhou University of TechnologyLanzhou 730000China

Despite having significant effects on social contagions,individual heterogeneity has frequently been overlooked in earlier *** better understand the complexity of social contagions,a non-Markovian model incorporating heterogeneous social influence and adoption thresholds is *** theoretical analysis,a generalized edge-based compartmental theory which considers the heterogeneities of social influence and adoption thresholds is *** on the final adoption size,the critical propagation probability,and the phase transition type,social contagions for adoption thresholds that follow normal distributions with various standard deviations,follow various distributions,and correlate with degrees are *** thresholds follow normal distributions,a larger standard deviation results in a larger final adoption size when the information propagation probability is relatively ***,when the information propagation probability is relatively high,a larger standard deviation results in a smaller final adoption *** thresholds follow various distributions,crossover phenomena in phase transition are observed when investigating the relationship of the final adoption size versus the average adoption threshold for some threshold *** thresholds are correlated with degrees,similar crossover phenomena occur when investigating the relationship of the final adoption size versus the degree correlation ***,we find that increasing the heterogeneity of social influence suppresses the effects of adoption threshold heterogeneity on social contagions in three *** theory predictions agree well with the simulation results.

关键词： complex networks social contagions heterogeneity phase transition

Ferritinophagy: A new idea for liver diseases regulated by ferroptosis

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Hepatobiliary & Pancreatic Diseases International 2024年第2期23卷 160-170页

作者： Zi-Bing Qian Jun-Feng Li Wan-Yuan Xiong Xiao-Rong Mao The First Clinical Medical College of lanzhou University Lanzhou 730000China Institute of Infectious Diseases The First Hospital of Lanzhou UniversityLanzhou 730000China Department of Infectious Disease The First Hospital of Lanzhou UniversityLanzhou 730000China

Background:The discovery of regulatory cell death has led to a breakthrough in the therapeutic *** forms of cell death,such as necrosis,apoptosis,pyroptosis,autophagy,and ferroptosis,play an important role in the development of liver *** general,more than one form of cell death pathways is responsible for the disease ***,it is particularly important to study the regulation and interaction of various cell death forms in liver *** sources:We performed a PubMed search up to November 2022 with the following keywords:ferritinophagy,ferroptosis,and liver *** also used terms such as signal path,inducer,and inhibitor to supplement the query ***:This review summarized the basic characteristics of ferritinophagy and ferroptosis and the regulation of ferroptosis by ferritinophagy and reviewed the key targets and treatment strategies of ferroptosis in different liver ***:Ferritinophagy is a potential therapeutic target in ferroptosis-related liver diseases.

关键词： Ferritinophagy Ferroptosis Liver disease

Efficient nitrite-to-ammonia electroreduction over Zr-Ni frustrated Lewis acid-base pairs

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Science China Chemistry 2024年第5期67卷 1707-1714页

作者： Ying Zhang Zhuohang Li Wenyu Du Kai Chen Ke Chu School of Materials Science and Engineering Lanzhou Jiaotong UniversityLanzhou 730070China

Electrochemical NO_(2)~--to-NH_(3) conversion(NO_(2)RR) offers a green route to NH_(3) electrosynthesis, while developing efficient NO_(2)RR catalysis systems at high current densities remains a grand challenge. Herein, we report an efficient Zr-NiO catalyst with atomically dispersed Zr-dopants incorporated in NiO lattice, delivering the exceptional NO_(2)RR performance with industriallevel current density(>0.2 A cm^(-2)). In situ spectroscopic measurements and theoretical simulations reveal the construction of ZrNi frustrated Lewis acid-base pairs(FLPs) on Zr-Ni O, which can substantially increase the number of absorbed nitrite(NO_(2)~-),promote the activation and protonation of NO_(2)~- and concurrently hamper the H coverage, boosting the activity and selectivity of Zr-NiO towards the NO_(2)RR. Remarkably, Zr-NiO exhibits the exceptional performance in a flow cell with high Faradaic efficiency for NH_(3) of 94.0% and NH_(3)yield rate of 1,394.1 μmol h^(-1)cm^(-2) at an industrial-level current density of 228.2 m A cm^(-2),placing it among the best NO_(2)RR electrocatalysts for NH_(3) production.

关键词： electrochemical nitrite-to-ammonia conversion frustrated Lewis acid-base pairs(FLPs) in situ spectroscopy theoretical computations

Highly strengthening and toughening biomimetic ceramic structures fabricated via a novel coaxially printing

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Journal of Advanced Ceramics 2024年第4期13卷 403-412页

作者： Kunkun Song Shengda Yang Ningqi Shao Yantang Zhao Peng He Yongfeng Wei Hengzhong Fan Yongsheng Zhang Qiangqiang Zhang State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China School of Civil Engineering and Mechanics Lanzhou UniversityLanzhou 730000China Key Laboratory of Mechanics on Disaster and Environment in Western China(lanzhou University) Ministry of EducationLanzhou 730000.China

Additive manufacturing technology,by manipulating and emulating inherent multiscale,multi-material,and multifunctional structures found in nature,has created new opportunities for constructing heterogeneous structures associated with special properties and achieving ultra-high mechanical performance and reliability in ceramic composite *** this study,we have developed an innovative fabrication method designated as coaxial 3D printing for the synchronous construction of two constituents into ceramic composites with a tooth enamel biomimetic ***,the stiff silicate and flexible epoxy served as a strengthening bridge and toughening layer,*** method differed from the traditional approach of randomly dispersing reinforcing components within a ceramic *** allowed for the direct creation of an internally effective three-dimensional reinforcement network structure in ceramic *** process facilitated synergistic deformation and simultaneous enhancement of multiple materials and hierarchical *** to the uniform distribution of internal stress and effective block of microcrack propagation,the biomimetically structured silicate/epoxy ceramic composite has demonstrated much significant enhancement in mechanical properties,includingcompressive strength(48.8±3.12MPa),flexuralstrength(10.39±1.23MPa),andflexuraltoughness(218.7±54.6kJ/m^(3)),which was 0.5,2.1,and 47.5 times as high as those of the intrinsic brittle silicate ceramics,***-situ characterization and multiscale finite element simulation of microstructural evolution during three-point bending deformation further validated multiple-step features of the fracture process(silicate bridge fracture,interface detachment,epoxy extraction,and rupture),which benefited from interpenetrating structural features achieved by coaxial printing to accomplish with the complex propagating routines of the crack deflection in silicate ceramic *** coaxia

关键词： coaxial 3D printing silicate ceramic composites enamel biomimetic microstructure strengthening bridge tougheninglayer crackdeflection

Lift-Off Effect of Koch and Circular Differential Pickup Eddy Current Probes

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 283-293页

作者： Guolong Chen Zheng Cao Shuaishuai Zhang Ji Wei Wei Gao Wuyin Jin School of Mechanical and Electrical Engineering Lanzhou University of TechnologyLanzhou 730050China

A flexible or planar eddy current probe with a differential structure can suppress the lift-off noise during the inspection of ***,the extent of the lift-off effect on differential probes,including different coil structures,*** this study,two planar eddy current probes with differential pickup structures and the same size,Koch and circular probes,were used to compare lift-off *** eddy current distributions of the probes perturbed by 0°and 90°cracks were obtained by finite element *** analysis results show that the 90°crack can impede the eddy current induced by the Koch probe even further at relatively low lift-off *** peak-to-peak values of the signal output from the two probes were compared at different lift-off distances using finite element analysis and experimental *** addition,the effects of different frequencies on the lift-off were studied *** results show that the signal peak-to-peak value of the Koch probe for the inspection of cracks in 90°orientation is larger than that of the circular probe when the lift-off distance is smaller than 1.2 *** addition,the influence of the lift-off distance on the peak-to-peak signal value of the two probes was studied via *** indicates that the influence becomes more evident with an increase in excitation *** research discloses the lift-off effect of differential planar eddy current probes with different coil shapes and proves the detection merit of the Koch probe for 90°cracks at low lift-off distances.

关键词： Eddy current testing Differential pickup probe Fractal Koch curve Flexible eddy current probe

New strategies for asymmetric photocatalysis: asymmetric organocatalytic/photoredox relay catalysis for efficient synthesis of polycyclic compounds containing vicinal amino alcohols

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Science China Chemistry 2024年第3期67卷 945-952页

作者： Jia-Lu Zhang Wen-Bo He Xiu-Qin Hu Peng-Fei Xu State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou 730000China State Key Laboratory of Veterinary Etiological Biology College of Veterinary MedicineLanzhou UniversityLanzhou Veterinary Research InstituteChinese Academy of Agricultural SciencesLanzhou 730000China MOE Frontiers Science Center for Rare Isotopes Lanzhou UniversityLanzhou 730000China

An asymmetric catalytic strategy in photocatalysis utilizing a chirality-induced approach through an organocatalytic/photoredox relay catalysis strategy is successfully achieved for the rapid construction of polycyclic compounds containing vicinal amino alcohols in a one-pot protocol. This methodology facilitates the efficient synthesis of diverse substituted polycyclic tetrahydroquinoline and benzofuran-derived vicinal amino alcohols, each containing five consecutive chiral centers, with high yields,excellent diastereoselectivities and enantioselectivities(up to 95% yield, >20:1 dr and 98% ee), under mild reaction conditions driven by sequential bifunctional squaramide organocatalyst-catalyzed [4+2] annulation and photocatalyst-catalyzed ketyl radical addition cyclization reaction process. Furthermore, investigations into the stereoselectivity mechanism and high-resolution mass spectrometry(HRMS) experiments on free radical trapping have provided evidence for elucidating the detailed mechanism of chirality-induced processes and chiral intermediate conversions in this procedure.

关键词： enantioselective photocatalysis asymmetric organocatalytic/photocatalysis relay catalysis five consecutive chiral centers chirality-induced strategy chirality vicinal amino alcohols

High-frequency magnetic properties of biphase Ce_(2)Fe_(17)N_(3)/α-Fe microflakes with easy-plane anisotropy

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Journal of Rare Earths 2024年第1期42卷 110-115,I0004页

作者： Ke Wang Hang Zhang Yuandong Huang Zhibiao Xu Fashen Li Tao Wang Key Laboratory for Magnetism and Magnetic Materials of MOE Lanzhou UniversityLanzhou730000China Key Laboratory of Special Function Materials and Structure Design Ministry of EducationLanzhou UniversityLanzhou730000China

Soft magnetic composites(SMCs)are effective as magnetic powder cores in an *** to high saturation magnetization,large magnetocrystalline anisotropy and high operating frequency of M(metal)-RE(rear earth)soft magnetic composites,it is possible to miniaturize inductor cores by reducing total loss,especially eddy current loss and excess loss at high *** this article,the characteristics of Ce_(2)Fe_(17)N_(3)/α-Fe(CFN/F)loss per volume and effective permeability reaching a high frequency of 3 MHz are *** biphase CFN/F composite exhibits a high permeability of 16 at 70 MHz,which is two times greater than that of pure Ce_(2)Fe_(17)N_(3)(CFN)*** total loss is as low as 545 mW/cm^(3)at 3 MHz and 6 *** direct current(DC)-bias properties have a percent of permeability exceeding 65% at H=7960 A/*** phenomenon indicates that our material has a higher working frequency and lower core loss than other materials;the biphase CFN/F structure is a promising and efficient approach for developing the miniaturized radio frequency(RF)inductor core.

关键词： High frequency Soft magnetic composites Easy-plane anisotropy Permeability spectra Core loss Rare earths