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Flotation separation of scheelite from calcite using luteolin as a novel depressant

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International Journal of minerals,Metallurgy and Materials 2024年第3期31卷 462-472页

作者： Xiaokang Li Ying Zhang Haiyang He Yu wu Danyu wu Zhenhao guan Faculty of Land and Resources Engineering Kunming University of Science and TechnologyKunming 650093China State Key Laboratory of Clean Utilization of Complex Non-Ferrous Metal Resources Kunming University of Science and TechnologyKunming 650093China

This paper proposes luteolin(LUT)as a novel depressant for the flotation-based separation of scheelite and calcite in a sodium oleate(NaOL)*** suitability of LUT as a calcite depressant is confirmed through micro-flotation *** pH=9,with LUT concentration of 50 mg·L^(-1) and NaOL concentration of 50 mg·L^(-1),scheelite recovery reaches 80.3%.Calcite,on the other hand,exhibits a recovery rate of 17.6%,indicating a significant difference in floatability between the two ***,the surface modifica-tions of scheelite and calcite following LUT treatment are characterized using adsorption capacity testing,Zeta potential analysis,Fourier transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),and atomic force microscopy(AFM).The study in-vestigates the selective depressant mechanism of LUT on *** capacity testing and Zeta potential analysis demonstrate sub-stantial absorption of LUT on the surface of calcite,impeding the further adsorption of sodium oleate,while its impact on scheelite is ***-IR and XPS analyses reveal the selective adsorption of LUT onto the surface of calcite,forming strong chemisorption bonds between the hydroxyl group and calcium ions *** directly illustrates the distinct adsorption densities of LUT on the two miner-al ***,LUT can effectively serve as a depressant for calcite,enabling the successful separation of scheelite and calcite.

关键词： scheelite calcite luteolin flotation depressant separation

Reduced magma generation and its implications for the Pulang giant porphyry Cu-polymetallic deposit in Northwest Yunnan,China

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Acta Geochimica 2024年第4期43卷 802-813页

作者： Jingwei guan Tao Ren Lei Wang Shenjin guan Lianrong wu Baosheng Shi Faculty of Land Resources Engineering Kunming University of Science and TechnologyKunming 650093People’s Republic of China Diqing Nonferrous Metals Co. LtdShangri-La 674400People’s Republic of China

The Pulang giant porphyry Cu-Mo polymetallic deposit is located in the Zhongdian area in the center of the Sanjiang Tethys tectonic domain,which was formed by the westward subduction of the Garze-Litang oceanic slab beneath the Zhongza ***-pyrrhotite-pyritemolybdenite occurs as disseminations,veins,veinlets,and stockworks distributed in the K-silicate alteration zone in the monzonite porphyry,which is superimposed by *** chemical compositions of biotite and amphibole analyzed by electron probe microanalysis(EPMA)indicate that the ore-forming magma and exsolved fluids experienced a continuous decrease in the oxygen fugacity(fO_(2)).Primary amphibolite and biotite(type I)crystallized at relatively high temperatures(744-827°C)and low fO_(2)(log fO_(2)=−12.26 to−11.91)during the magmatic *** fluids exsolved from the magma have a relatively lower temperature(621-711°C)and fO_(2)(log fO_(2)=−14.36 to−13.32)than the original *** addition,the presence of a high abundance of pyrrhotite and an insufficiency of primary magnetite and sulfate in the ore(i.e.,anhydrite and gypsum)indicate that the deposit may be a reduced porphyry *** and fluid fO_(2)results,combined with previous research on magmatic fO_(2)at the Pulang deposit,indicate that the magma associated with the reduced Pulang ore assemblages was initially generated as a highly oxidized magma that was subsequently reduced by sedimentary rocks of the Tumugou Formation.

关键词： Porphyry deposit Oxygen fugacity(fO_(2)) Contamination of surrounding rock Pulang Zhongdian arc

Two polyoxovanadoborates with over 100 nuclei assembled from a {V_(14)Co_(12)B_(72)} cluster

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Science China Chemistry 2024年第8期67卷 2578-2585页

作者： Shuang-Xue wu Yu-Jiao Dong Yang Yang Chao Qin Chun-Yi Sun Wei guan Xin-Long Wang Zhong-min Su Key Laboratory of Polyoxometalate and Reticular Material Chemistry of ministry of Education Northeast Normal UniversityChangchun 130024China School of Chemistry and Environmental Engineering Changchun University of Science and TechnologyChangchun 130013China Key Laboratory of Advanced Materials of Tropical Island Resources Hainan UniversityHaikou 570228China

Combining theoretical prediction and experimental exploration, the first sandwich-type polyoxovanadoborate(POVB) with an odd number of nuclei, [V_(11)B_(26)O_(73)(OH)_(10)]^(8-)(1), was discovered under hydrothermal conditions. Density-functional theory(DFT)gives a rationalization for the existence of this structure and the structural feature is consistent with the {V_NB_(2N+X)}(X = 2, 4, 6, 8)general formula. Excitingly, when Co and 1,10-phenanthroline(phen) are introduced into the synthesis of vanadoborates system,a 100-nuclei [Co_6(phen)_(10)(H_(2)O)_8][V_(14)Co_(12)B_(72)O_(144)(OH)_(20)]·28H_(2)O(2) and a 102-nuclei [Co_6(phen)_(14)(H_(2)O)_(4)][V_(14)Co_(12)B_(72)O_(144)(OH)_(20)]·23H_(2)O(3) with the same core structure of [V_(14)Co_(12)B_(72)]^(12-)are obtained. The vase-shaped [V_(14)Co_(12)B_(72)] polyanion is a multilayered sandwich-type structure containing seven distinct structural layers and is the largest known POVB. Furthermore, 2demonstrates exceptional thermal and chemical stability and serves as an efficient and stable catalyst for the photoreduction of carbon dioxide.

关键词： boronate metallic materials polyoxovanadoborates density functional theory photocatalysis CO_(2)reduction

A_(2)B_(7)-type La-Mg-Ni alloys prepared by Mg thermal diffusion for improved hydrogen storage performance

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Rare Metals 2024年第7期43卷 3260-3272页

作者： Yong-Xi Zhang guan-Jiu wu Jing Gu Hong-Xing Kang Yuan Li Di Zhou Wen-Feng Wang Lu Zhang Shu-min Han Hebei Key Laboratory of Applied Chemistry School of Environmental and Chemical EngineeringYanshan UniversityQinhuangdao 066004China Department of Chemistry and Biochemistry San Diego State UniversitySan DiegoCA92182-1030USA State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China

A novel approach based on thermal diffusion was used to achieve controllable Mg content in A_(2)B_(7)-type La-Mg-Ni-based *** formation mechanism of the A_(2)B_(7)-type phase as a result of the thermal diffusion process and the effect of Mg content on hydrogen storage performance were investigated.X-ray diffraction(XRD)patterns and Rietveld refinement results showed that increased Mg transformed the LaNi_(5)phase in the La_(0.74)Sm_(0.03)Y_(0.23)Ni_(4.32)Al_(0.04)precursor alloy into a superlattice *** electron microscopy(SEM)images showed that Mg was evenly distributed in the alloy *** in the superlattice significantly inhibited the phase decomposition of the superlattice structure during the hydrogen absorption/desorption *** A_(2)B_(7)-type La_(0.57)Sm_(0.02)Y_(0.18)Mg_(0.23)Ni_(3.38)Al_(0.03)alloy composed of Gd_(2)Co_(7)and Ce_(2)Ni_(7)phases was successfully *** pressure-composition isotherm profiles showed that the alloy had a hydrogen storage capacity as high as 1.73 wt%,with good cycling *** 50 cycles of hydrogen absorption/desorption,the alloy retained a hydrogen storage capacity of 1.45 wt%,with a capacity retention rate of up to 84.28%.The Mg thermal diffusion process thus provides a new approach for the controlled preparation of La-Mg-Ni-based alloys.

关键词： La-Mg-Ni-based hydrogen storage alloy A_(2)B_(7)-type superlattice alloy Mg thermal diffusion process Phase transformation Hydrogen storage property

Effect of Mn addition on microstructure and mechanical properties of GX40CrNiSi25-12 austenitic heat resistant steel

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China Foundry 2024年第3期21卷 205-212页

作者： guan-yu Jiang Meng-wu wu Xiao-guang Yang Hui Wang Yu-yuan Zhu Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory Xiangyang 441000HubeiChina Wescast Industries(China)Co. Ltd.Wuhan 430100China

Three types of steels were designed on the basis of GX40CrNiSi25-12 austenitic heat resistant steel by adding different Mn contents(2wt.%,6wt.%,and 12wt.%).Thermodynamic calculation,microstructure characterization and mechanical property tests were conducted to investigate the effect of Mn addition on the microstructure and mechanical properties of the austenitic heat resistant *** show that the matrix structure in all the three types of steels at room temperature is completely *** NbC and M_(23)C_(6)precipitate at grain boundaries of austenite *** the increase of Mn content,the number of carbides increases and their distribution becomes more *** the Mn content increases from 1.99%to 12.06%,the ultimate tensile strength,yield strength and elongation increase by 14.6%,8.0%and 46.3%,*** improvement of the mechanical properties of austenitic steels can be explained by utilizing classic theories of alloy strengthening,including solid solution strengthening,precipitation strengthening,and grain *** increase in alloy strength can be attributed to solid solution strengthening and precipitation strengthening caused by the addition of *** improvement of the plasticity of austenitic steels can be explained from two aspects:grain refinement and homogenization of precipitated phases.

关键词： austenitic heat resistant steel manganese microstructure mechanical properties

Grasp Detection with Hierarchical Multi-Scale Feature Fusion and Inverted Shuffle Residual

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Tsinghua Science and Technology 2024年第1期29卷 244-256页

作者： Wenjie Geng Zhiqiang Cao Peiyu guan Fengshui Jing min Tan Junzhi Yu State Key Laboratory of Multimodal Artificial Intelligence Systems Institute of AutomationChinese Academy of SciencesBeijing 100190China School of Artificial Intelligence University of Chinese Academy of SciencesBeijing 100049China Department of Advanced Manufacturing and Robotics College of EngineeringPeking UniversityBeijing 100871China

Grasp detection plays a critical role for robot *** pixel-wise grasp detection networks with encoder-decoder structure receive much attention due to good accuracy and ***,they usually transmit the high-level feature in the encoder to the decoder,and low-level features are *** is noted that low-level features contain abundant detail information,and how to fully exploit low-level features remains ***,the channel information in high-level feature is also not well ***,the performance of grasp detection is *** solve these problems,we propose a grasp detection network with hierarchical multi-scale feature fusion and inverted shuffle *** low-level and high-level features in the encoder are firstly fused by the designed skip connections with attention module,and the fused information is then propagated to corresponding layers of the decoder for in-depth feature *** a hierarchical fusion guarantees the quality of grasp ***,an inverted shuffle residual module is created,where the high-level feature from encoder is split in channel and the resultant split features are processed in their respective *** such differentiation processing,more high-dimensional channel information is kept,which enhances the representation ability of the ***,an information enhancement module is added before the encoder to reinforce input *** proposed method attains 98.9%and 97.8%in image-wise and object-wise accuracy on the Cornell grasping dataset,respectively,and the experimental results verify the effectiveness of the method.

关键词： grasp detection hierarchical multi-scale feature fusion skip connections with attention inverted shuffle residual

Effects of hot deformation and in-situ ZrB2 particle on microstructure and tensile performance of AA7085 composite sheets

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Journal of Iron and Steel Research International 2024年第7期31卷 1778-1791页

作者： Jiang-jing wu Xi-zhou Kai Chuang guan Yu-tao Zhao School of Material Science and Engineering Jiangsu UniversityZhenjiang 212013JiangsuChina

To provide a new idea to reduce anisotropy for sheets in the thickness direction by microstructure modification and,mean-while,maintain or even enhance tensile performance,the in-situ ZrB2 particle/AA7085 composite sheets with thicknesses of 1,2,3,and 6 mm were *** as-cast grain size was significantly refined by the heterogeneous nucleus of the ZrB2 *** microstructure results show that severe hot deformation converts as-cast disordered microstructure into a sequential microstructure by crushing the remanent phases and matrix into a fiber *** the solid solution and aging heat treatment,the composite sheets exhibit largely recrystallized grains compared with partially recrystallized grains in the matrix sheets,and weak or even free texture exists in the *** grain size in the composite sheets decreases with the increase in thickness *** the thickness range of 1-3 mm,the composite sheets maintain a similar tensile per-formance as that in matrix sheets,while the strength and ductility in the 6-mm-thick composite sheet are improved.

关键词： Composite sheet Grain structure Texture Dislocation Strengthening

Analysis method and experimental study of ice accumulation detection signal based on Lamb waves

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Chinese Journal of Aeronautics 2024年第8期37卷 388-403页

作者： Yanxin ZHANG Hongjian ZHANG Xian YI Binrui wu Xianlei guan Jianjun XIONG Key Laboratory of Icing and Anti/De-icing China Aerodynamics Research and Development CenterMianyang 621000China State Key Laboratory of Aerodynamics China Aerodynamics Research and Development CenterMianyang 621000China

A quantitative identification method for in-flight icing has the capability to significantly enhance the safety of aircraft *** guided waves have the unique advantage of detecting icing in a relatively large area,but quantitative identification of ice layers is a *** this paper,a quantitative identification method of ice accumulation based on ultrasonic guided waves is ***,a simulation model for the wave dynamics of piezoelectric coupling in three dimensions is established to analyze the propagation characteristics of Lamb waves in a structure consisting of an aluminum plate and an ice *** wavelet transform method is utilized to extract the Time of Flight(ToF)or Time of Delay(ToD)of S_(0)/B_(1) mode waves,which serves as a characteristic parameter to precisely determine and assess the level of ice ***,an experimental system is developed to evaluate the feasibility of Lamb waves-based icing real-time detection in the presence of spray ***,a combination of the Hampel median filter and the moving average filter is developed to analyze ToF/ToD *** simulation results reveal a positive correlation between geometric dimensions(length,width,thickness)of the ice layer and ToF/ToD of B1 mode waves,indicating their potential as indicators for quantifying ice *** results of real-time icing detection indicate that ToF/ToD will reach greater peak values with the growth of the arbitrary-shaped ice layer until saturation to effectively predict the simulation *** study lays a foundation for the practical application of quantitative icing detection via ultrasonic guided waves.

关键词： Ice Ice accumulation Ultrasonic sensor Ultrasonic guided wave Lamb wave Wavelet transform

Island biogeography theory and the habitat heterogeneity jointly explain global patterns of Rhododendron diversity

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Plant Diversity 2024年第5期46卷 565-574页

作者： Yanwei guan Yongru wu Zheng Cao Zhifeng wu Fangyuan Yu Haibin Yu Tiejun Wang School of Geographical Sciences and Remote Sensing Guangzhou UniversityGuangzhou 510006China School of Life Sciences Guangzhou UniversityGuangzhou 510006China Department of Natural Resources Faculty of Geo-Information and Earth Observation(ITC)University of TwenteDrienerlolaan 5Enschede 7522 NBthe Netherlands

Mountain biodiversity is of great importance to biogeography and ***,it is unclear what ecological and evolutionary processes best explain the generation and maintenance of its high levels of species *** this study,we determined which of six common hypotheses(e.g.,climate hypotheses,habitat heterogeneity hypothesis and island biogeography theory)best explain global patterns of species diversity in *** found that Rhododendron diversity patterns were most strongly explained by proxies of island biogeography theory(i.e.,mountain area)and habitat heterogeneity(i.e.,elevation range).When we examined other relationships important to island biogeography theory,we found that the planimetric area and the volume of mountains were positively correlated with the Rhododendron diversity,whereas the‘mountains-to-mainland’distance was negatively correlated with Rhododendron diversity and shared *** findings demonstrate that Rhododendron diversity can be explained by island biogeography theory and habitat heterogeneity,and mountains can be regarded as islands which supported island biogeography theory.

关键词： Mountain biodiversity Rhododendron Island biogeography theory Habitat heterogeneity Biogeographical hypotheses Plant diversity