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Chinese Journal of Chemistry 2021年第6期39卷 1565-1572页

作者： Rui Fu Luyao kou.ke Gao Shaofang Zhou Xiaoguang Bao College of Chemistry Chemical Engineering and Materials ScienceSoochow University199 Ren-Ai RoadSuzhou Industrial ParkSuzhouJiangsu 215123China

The employment of α-iminometallocarbenes to construct valuable N-containing compounds has attracted significant research ***,the nucleophilic addition of nitrosoarenes with the α-imino rhodium carbene species(I),which is derived from Rh_(2)(ll)-catalyzed denitrogenation of 3-diazoindolin-2-imines,to produce synthetically useful 2-iminoindolin-nitrones is ***,the N-attack of nitrosoarenes with the carbene site of I is *** the analogous Rh_(2)(ll)-catalyzed reaction of nitrosoarenes with N-sulfonyl-1,2,3-triazoles reported by Li and co-workers(***.2014,16,6394),however,the O-attack of nitrosoarenes with the carbene site of α-imino rhodium carbene species(II)is more favorable to occur than the *** subsequent transformation to yield the product of N-acylamidines is rationalized based on computational *** mechanistic differ-ences for the reactions of nitrosoarenes with a-imino rhodium carbene species I and II are discussed.

关键词： a-lmino rhodium carbene Nitrosoarene Reaction mechanism Chemo-selectivity Density functional theory

Fairness-oriented routing algorithm joint with power control and channel assignment for multi-radio multi-channel wireless mesh networks

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The Journal of China Universities of Posts and Telecommunications 2014年第5期21卷 55-60页

作者： LIU Kai-ming MA Tao LIU Yuan-an kou.ke-hao School of Electronic Engineering Beijing University of Posts and Telecommunications Beijing key Laboratory of Work Safety Intelligent Monitoring Beijing University of Posts and Telecommunications

The multi-radio multi-channel wireless mesh network （MRMC-WMN） draws general attention because of its excellent throughput performance, robustness and relative low cost. The closed interactions among power control （PC）, channel assignment （CA） and routing is contributed to the performance of multi-radio multi-channel wireless mesh networks （MRMC-WMNs）. However, the joint PC, CA and routing （JPCR） design, desired to achieve a global optimization, was poor addressed. The authors present a routing algorithm joint with PC and CA （JPCRA） to seek the routing, power and channel scheme for each flow, which can improve the fairness performance. Firstly, considering available channels and power levels, the routing metric, called minimum flow rate, is designed based on the physical interference and Shannon channel models. The JPCRA is presented based on the genetic algorithm （GA） with simulated annealing to maximize the minimum flow rate, an non-deterministic polynomial-time hard （NP-Hard） problem. Simulations show the JPCRA obtains better fairness among different flows and higher network throughput.

关键词： channel assignment routing power control mesh networks multi-radio multi-channel

Capacity analysis of based-regular-topologies cognitive wireless mesh networks with power control

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The Journal of China Universities of Posts and Telecommunications 2013年第5期20卷 71-78页

作者： kou.ke-hao TANG Bi-hua LIU Kai-ming MA Tao School of Electronic Engineering Beijing University of Posts and Telecommunications Beijing key Laboratory of Work Safety Intelligent Monitoring Beijing University of Posts and Telecommunications

Capacity analysis is a fundamental and essential work for evaluating the performance of cognitive wireless mesh network （CWMN） which is considered a promising option for the future network. Power control is an efficient way to avoid interference and improve capacity of wireless mesh networks. In this paper, a quantitative result of the per-node average throughput capacity of CWMN with power control is deduced for the first time, which is much helpful for understanding the limitations of CWMN. Firstly, under the large-scale channel fading model and protocol interference model, a closed-form expression for the maximum channel capacity of each node with power control is presented, under the constraint that the interference tolerated by the primary users （PUs） does not exceed a threshold. And then, with the deduced channel capacity result, the per-node average throughput capacity of CWMN is derived based on two regular topologies, i.e. square topology and triangle topology. The simulation results indicate that the capacity is effectively improved with power control, and affected by topology, tolerated interference threshold, the number of cognitive users （CUs） and primary users （PUs）.

关键词： capacity cognitive wireless mesh networks power control regular topologies

Morphological Evolution of Self-Assembled Sodium Dodecyl Sulfate/Dodecyltrimethylammonium Bromide@Epoxy-β-Cyclodextrin Supramolecular Aggregates Induced by Temperature

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Journal of Renewable Materials 2024年第4期12卷 629-641页

作者： Qingran Meng Wenwen Xu Zuobing Xiao Qinfei ke Xingran kou key Laboratory of Textile Science&Technology Ministry of EducationCollege of TextilesDonghua UniversityShanghai201620China Collaborative Innovation Center of Fragrance Flavor and Cosmetics School of Perfume and Aroma Technology(Shanghai Research Institute of Fragrance&Flavour Industry)Shanghai Institute of TechnologyShanghaiChina

Bio-based cyclodextrins(CDs)are a common research object in supramolecular *** special cavity structure of CDs can form supramolecular self-assemblies such as vesicles and microcrystals through weak interaction with guest *** different forms of supramolecular self-assemblies can be transformed into each other under certain *** regulation of supramolecular self-assembly is not only helpful to understand the self-assembly principle,but also beneficial to its *** the present study,the self-assembly behavior of epoxy-β-cyclodextrin(EP-β-CD)and mixed anionic and cationic surfactant system(sodium dodecyl sulfate/dodecyltrimethylammonium bromide,SDS/DTAB)in aqueous solution was *** and particle size characterization found that the SDS/DTAB@EP-β-CD complex,as the basic building unit,self-assembled into worm-like micelles at lower temperatures and vesicles at higher *** magnetic resonance(NMR)and Fourier transform infrared spectroscopy(FT-IR)analysis revealed that the driving force for the formation of vesicles and worm-like micelles was the hydrogen bonds between EP-β-CD molecules,while water molecules played an important role in promoting vesicle formation between SDS/DTAB@EP-β-CD ***,the mechanism of the morphologic transformation of SDS/DTAB@EP-β-CD supramolecular aggregates induced by temperature was elucidated by exploring the self-assembly process,which may provide an excellent basis for the development of delivery carriers.

关键词： Epoxy-β-cyclodextrin SDS/DTAB self-assembly temperature morphological evolution

High-precision temperature retrieval algorithm and verification for mesospheric airglow spectrum photometer

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Science China Earth Sciences 2024年第5期67卷 1639-1651页

作者： Shuqi NIU Haiyang GAO Zhaoai YAN ke REN Leilei kou Baichuan JIANG Lingbin BU key Open Laboratory of Aerosol and Cloud Precipitation of China Meteorological Administration Nanjing 210044China School of Atmospheric Physics Nanjing University of Information Science and TechnologyNanjing 210044China National Space Science Center Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100190China

Photometric technology,characterized by its compact structure and relatively high stability,finds wide application in measuring airglow *** instrumentation is anticipated to assume a pivotal role as the primary equipment for extensive network observations of middle and upper atmospheric temperatures in China,thereby providing crucial support for space environmental monitoring and atmospheric dynamic ***,susceptibility to various factors such as instrument inconsistency,variability in observation conditions,and alterations in the background atmospheric environment across different stations poses a challenge,potentially resulting in data inconsistencies in network *** response to these challenges,we propose a multiple-parameter iterative inversion(MPII)algorithm for temperature retrieval based on a mesospheric airglow spectrum photometer(MASP)developed by our research *** algorithm accurately identifies the center of the image circle,corrects image distortion,and thereby obtains an accurate synthetic spectrum reflective of actual *** encompasses five adjustable parameters:sky background light,atmospheric temperature,filter temperature,optical system focal length,and degree of synthetic spectrum *** to traditional methods,significant enhancements in the accuracy of the inverted temperature are *** validate the effectiveness of the MPII algorithm,we conducted combined active and passive remote sensing synchronous measurements using MASP in conjunction with a sodium fluorescence Doppler lidar developed by the National Space Science *** utilizing the lidar temperature as a reference,atmospheric background radiation is mitigated from the MASP data,and the temperature is inverted using the MPII *** analysis with the traditional method reveals that temperatures calculated by the MPII algorithm exhibit better consistency than those observed by the lidar.

关键词： Temperature inversion Airglow spectrum photometer Rotational spectral lines Sodium fluorescence Doppler lidar Comparative observations

The Changhsingian Foraminiferal Fauna of the Meishan D Section, Zhejiang, China, and their Ecostratigraphic Implications

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Acta Geologica Sinica(English Edition) 2018年第4期92卷 1299-1323页

作者： ke Xue LUO Liang WEI Yi kou Xiaohu ZHANG Zongyan HE Weihong Institute of Geological Survey China University of Geosciences China Geological Survey Chengdu Center Safety Engineering College North China Institute of Science & Technology China Geological Survey Wuhan Center School of Earth Sciences China University of Geosciences

Samples were collected continuously and systematically from Beds 2 to 30 of the Meishan D section, and nearly 4,000 foraminiferal specimens were recognized. In total, 72 species （partially including undetermined species and conformis species） in 34 genera of foraminifers were identified. Twelve foraminiferal community zones were established from Beds 2 to 27 based on the abundance, dominance, diversity, and equitability of the foraminiferal fauna and a functional morphological analysis of the dominant and characteristic species. The habitat type indicated by each community zone and the sedimentary features were used to determine the paleo-water depths and the relative changes in sea level. We generated curves of both the habitat type and the hydrodynamic conditions, which together indicate the relative changes in the paleo-water depth and the substrate features in the studied area during the Changhsingian. This study discusses the possible relationship between the foraminiferal community zones and the sea-level changes based on a statistical analysis of the foraminiferal community zones.

关键词： foraminifera Habitat type Changhsingian ecostratigraphy Meishan D section

Duality of the fatigue behavior and failure mechanism in notched specimens of Ti-7Mo-3Nb-3Cr-3Al alloy

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Journal of Materials Science & Technology 2020年第15期47卷 204-214页

作者： Zhihong Wu Hongchao kou Nana Chen Mengqi Zhang ke Hua Jiangkun Fan Bin Tang State key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China

An interesting phenomenon of dual S-N fatigue behavior is investigated in a metastable β titanium alloy,Ti-7 Mo-3 Nb-3 Cr-3 Al notched cylindrical specimens with an elastic stress concentration factor of Kt=*** studies revealed all specimens,and irrespective of lifetime,failed from the specimen surface because of stress concentration occurs at the notch ***,the short-life-distribution is usually associated with surface-failure-without-facets and the long-life-distribution generally occurs due to *** competing failure leads to increasing the variability in fatigue lifetime and further facilitates the difficulty in prediction of fatigue ***-initiation area characterization was conducted by using mechanical grinding,focused ion beam milling and subsequent electron backscattered diffraction(EBSD) analysis of the 2 D section across faceted *** show that the α_p particles(especially the elongated α_p particles) well-oriented for basal slip activation is a preferential fatigue-critical microstructural ***,the β+α_s matrix has a higher KAM value than the α_p particles in fatigued microstructures and significant dislocation activity in the form of dislocation tangles is observed in α_p boundaries.

关键词： High cycle fatigue Metastableβtitanium alloys Notch effects S-N curves Surface crack initiation

Magnetostratigraphy and Anisotropy of Magnetic Susceptibility of the Lulehe Formation in the Northeastern Qaidam Basin

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Acta Geologica Sinica(English Edition) 2013年第2期87卷 576-587页

作者： ke Xue JI Junliang ZHANG kexin kou Xiaohu SONG Bowen WANG Chaowen Institute of Geophysics and Geomatics China University of Geosciences State key Laboratory of Biogeology and Environmental Geology China University of Geosciences China Geological Survey Nanjing Center Faculty of Earth Sciences China University of Geosciences Geological Survey of China University of Geosciences

The timing of onset of deposition of the Lulehe Formation is a significant factor in understanding the genesis of the Qaidam basin and the evolution of the Tibetan Plateau. Here, we describe a detailed magnetostratigraphic and magnetic fabric study of the middle and lower parts of the Lulehe Formation. A total of 234 samples were collected from 117 sites throughout a thickness of almost 460 m of fluvial and lacustrine deposits at the Xitieshan section in the northeastern Qaidam basin. Out of these sites, 94 sites yielded well-defined characteristic remanent magnetization components by stepwise thermal demagnetization and were used to establish the magnetostratigraphy of the studied section. Based on correlation with the geomagnetic polarity timescale, the studied section spans the period from 53.8 Ma to 50.7 Ma. Our results show a three-fold decrease in sedimentation rates as well as marked change in facies from braided river to delta and shore-shallow lake around 52.6 Ma, which suggests tectonic uplift of the northeastern Qaidam basin margin ridge was rapid at the onset of formation of the Qaidam basin and subsequently weakened after 52.6 Ma. The anisotropy of magnetic susceptibility results indicate that tectonic compression stress had reached the northeastern Tibetan Plateau by the early stages of Indo-Eurasian plate collision and that the direction of stress in the study area was NE-SW. Furthermore, a weakening of tectonic compression stress around 52.6 Ma is consistent with sedimentary records. The age of initial deposition of the Qaidam basin （around 53.8 Ma） was almost synchronous with that of the Qiangtang, Hoh Xil, Xining, and Lanzhou basins, which implies that stress was transferred rapidly through the Tibetan Plateau during or immediately after the onset of Indo-Eurasian collision.

关键词： magnetostratigraphy magnetic anisotropy Lulehe Formation Qaidam basin TibetanPlateau

New insight into deformation induced α variant selection in a metastable β titanium alloy during isothermal compression at 600℃

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Progress in Natural Science:Materials International 2021年第3期31卷 471-476页

作者： ke Hua Fan Zhang Hongchao kou Qiong Wan Yongliang Zhang Weimin Gan Jinshan Li State key Laboratory of Solidification Processing Northwestern Polytechnical University Center of Advanced Lubrication and Seal Materials Northwestern Polytechnical University German Engineering Materials Science Center at MLZ Helmholtz-Center Geesthacht

Variant selection during phase transformation creates a specific transformation texture and finally affects the mechanical properties of the *** transformation lattice deformation associated selection mechanism has not been well *** the present work,the a variant selection in a Ti-7 Mo-3 Nb-3 Cr-3 Al alloy under isothermal compression at low temperature was *** results show that the selection of the a variants is strongly affected by the imposed strain and the load with the dependence on the effective strain distribution induced by macroscopic shape *** the center region of the compressed sample,4 Burgers orientation relationship(BOR) variants orienting in four different directions and forming two sets of ’cross-shaped’ clusters were *** variants consumed the maximum strain contribution to the macroscopic *** the edge region of the compressed sample,only 2 BOR variants with 90°/ or 10°/ disorientation relationship were *** selection criterion was still obeyed by the variants but with restriction from the local effective strain distribution induced by macroscopic shape *** present work provides the clear information on the interweaving of the imposed compression with the internal lattice deformation and its impact on the β to α transformation variant selection.

关键词： Variant selection Phase transformation Titanium alloy Strain accommodation

Dynamic recrystallization and phase transformation behavior of a wrought β-γ TiAl alloy during hot compression

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Progress in Natural Science:Materials International 2020年第4期30卷 517-525页

作者： Lei Zhu Jinshan Li Bin Tang Fengtong Zhao ke Hua Shaopeng Yan Hongchao kou State key Laboratory of Solidification Processing Northwestern Polytechnical University Shaanxi key Laboratory of High-Performance Precision Forming Technology and Equipment Northwestern Polytechnical University

The dynamic recrystallization(DRX) and phase transformation(PT) behavior of a wrought β-γ TiAl alloy during hot compression under various deformation temperatures were investigated. The typical work hardening and flow softening features indicated that DRX was the dominating softening mechanism. Both γ-DRX and β-DRX took place during the hot compression. γ-DRX was triggered at all compression temperatures, while the β-DRX was induced when the compression temperature was above 1000 °C. The hot deformation kinetics was calculated, which showed that DRX behavior existed in the whole hot compression process, and the DRX volume fraction increased with the increase of the compression temperature. Combined with the microstructure observation, it concluded that the β/B2+α2→γ PT occurred at 850 °C and 1000 °C, while the γ→β/B2 PT happened at 1050 °C during hot compression, which is important to optimize microstructure. Moreover, the hot compression mechanism changed from dislocation gliding to grain-boundary sliding was discussed.

关键词： β-γ TiAl alloy Hot compression Dynamic recrystallization Microstructure Phase transformation