Factors controlling the geochemical differences between two types of rhyolites in the middle Okinawa Trough

Yuxiang Zhang,Zhigang Zeng,Xiaoyuan Wang,Shuai Chen,Xuebo Yin 한국지질과학협의회 2020 Geosciences Journal Vol.24 No.1

The origin of the felsic volcanic rocks in the Okinawa Trough (OT) remains uncertain. In the middle Okinawa Trough (MOT), two types of rhyolites (type 1 and type 2 rhyolites) have been recognized. Research on the diverse volcanic rocks should be prioritized to determine the magmatic origins of these rocks. Consequently, in this article, the geochemical differences and controlling factors for these two types of MOT rhyolites are systematically discussed. Type 2 rhyolites have higher Dy/Yb and Nb/Ta ratios than type 1 rhyolites, implying that the former might be influenced by a greater contribution of amphibole. Quantitative models suggest that type 1 rhyolites could have formed via the remelting of andesites when amphiboles remain in the source, whereas type 2 rhyolites could have formed without residual amphiboles. These two distinct melting models effectively explain most discrepancies between the major and trace element compositions of type 1 and 2 rhyolites. Additionally, the lower Mg# and δEu values of type 2 rhyolites are partly caused by significant magmatic differentiation. Quasi-linear correlations between some major oxides, trace element ratios and Sr-Nd isotopic ratios for type 2 rhyolites suggest that these rhyolites might have been contaminated by crustal rocks or melts with compositions similar to those of the Kueishantao (KST) andesites or the Middle Miocene upper crustal rocks of SW Japan. Therefore, isotopically enriched crustal materials likely remain in the OT crust.

Plasma-catalytic decomposition of ethyl acetate over LaMO3 (M = Mn, Fe, and Co) perovskite catalysts

Yuxiang Cai,Xinbo Zhu,Wenshuo Hu,Chenghang Zheng,Yangyang Hu,Menghan Chen,Xiang Gao 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.70 No.-

Plasma-catalytic decomposition of low concentration ethyl acetate with LaMO3 (M = Co, Mn and Fe)perovskite catalyst was investigated in a coaxial dielectric barrier discharge (DBD) reactor. Thecombination of perovskite catalyst and plasma enhanced ethyl acetate decomposition, and the activitysequence was LaCoO3> LaMnO3> LaFeO3. Characterizations results indicated that the activation ofsurface oxygen species and amount of oxygen vacancies contributed to ethyl acetate decompositionremarkably. FT-IR analysis demonstrated that the employment of LaCoO3 catalyst also reduced theamount of unwanted by-products. Based on these results, reaction mechanism of ethyl acetate plasmacatalyticdecomposition process was proposed.

A dual-experience pool deep reinforcement learning method and its application in fault diagnosis of rolling bearing with unbalanced data

Yuxiang Kang,Guo Chen,Wenping Pan,Xunkai Wei,Hao Wang,Zhiyuan He 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.6

A dual-experience pool deep reinforcement learning (DEPDRL) model is proposed for rolling bearing fault diagnosis with unbalanced data. In this method, a dualexperience pool structure is designed to store the sample data of majority and minority classes. A parallel double residual network model is established to extract deep features of the majority and minority input samples, respectively. In the process of training, the proposed balanced cross-sampling technique is used to randomly select samples from dual-experience pool in a certain proportion to realize the training of a double residual network model. We show the effectiveness of our method on three standard data sets, and compared with Resnet18, DCNN, DQN and DQNimb methods, the results show that DEPDRL has the best performance. Finally, with wavelet time-frequency graph as input, DEPDRL is applied to rolling bearing fault diagnosis with unbalanced test data. The results show that on a variety of unbalanced data sets, both the diagnostic accuracy and the G-means value of the DEPDRL are more than 5 % higher than other algorithms, which fully indicates that the DEPDRL has a very high fault diagnosis ability of rolling bearing with unbalanced data.

Integration of ZnO nanowires in gated field emitter arrays for large-area vacuum microelectronics applications

Long Zhao,Yuxiang Chen,Yuanming Liu,Guofu Zhang,Juncong She,Shaozhi Deng,Ningsheng Xu,Jun Chen 한국물리학회 2017 Current Applied Physics Vol.17 No.1

Addressable field emitter arrays (FEAs) have important applications in vacuum electronic devices. However, it is important to integrate nanowire emitters into a gated structure without influencing the device structure and maintain the excellent field emission properties of nanowire emitters in the FEAs after the fabrication process. In this study, gate-structure ZnO nanowire FEAs were fabricated by a microfabrication process. The structure combines a planar gate and an under-gate, which is compatible with the preparation of ZnO nanowire emitters. The effect of electrode materials on the field emission properties of ZnO nanowires was studied using a diode structure, and it was found that ZnO nanowire pads on indium-tin-oxide (ITO) electrode showed better field emission performance compared with chromium (Cr) electrode. In addition, effective emission current modulation by the gate voltage was achieved and the addressing capability was demonstrated by integrating the ZnO nanowire FEAs in a vacuum-encapsulated field emission display. The reported technique could be a promising route to achieve large area addressable FEAs.

Dynamic model-based back-stepping control design for-trajectory tracking of seabed tracked vehicles

Hong Xiong,Yuxiang Chen,Yuxiao Li,Hong Zhu,Chunliang Yu,Jingguo Zhang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.8

Tracked vehicles are widely used as seabed production tools to ensure a stable motion on soft sediments. However, the slippage resulted from the complex nonlinear trackterrain interaction while trajectory tracking causes problems for precisely predicting the motion. Accordingly, a “proper” motion control method is necessitated. This work proposes a novel dynamic modeling approach and motion control method for seabed tracked vehicles under nonholonomic constraints, with the inclusion of the effects of the bulldozing resistance, compaction resistance, water resistance, and the direction and velocity of the current. The backstepping control based on a model-based proportional-integral-derivative three degrees-offreedom method is applied in the controller, and its stability is proven by Lyapunov theory. The effectiveness and accuracy of the method in controlling seabed tracked vehicles are validated by simulation examples.

¹H*-tree: 데이터 스트림의 다차원 분석을 위한 개선된 데이터 큐브 구조

심상예 ( Xiangrui Chen ),정우상 ( Yuxiang Cheng ),이연 ( Yan Li ),신숭선 ( Song-sun Shin ),이동욱 ( Dong-wook Lee ),배해영 ( Hae-young Bae ) 한국정보처리학회 2008 한국정보처리학회 학술대회논문집 Vol.15 No.2

In this paper, based on H-tree, which is proposed as the basic data cube structure for multi-dimensional data stream analysis, we have done some analysis. We find there are a lot of redundant nodes in H-tree, and the treebuild method can be improved for saving not only memory, but also time used for inserting tuples. Also, to facilitate more fast and large amount of data stream analysis, which is very important for stream research, H*-tree is designed and developed. Our performance study compare the proposed H*-tree and H-tree, identify that H*-tree can save more memory and time during inserting data stream tuples.

Implications of Sarcopenia and Glucometabolism Parameters of Muscle Derived From Baseline and End-of-Treatment 18F-FDG PET/CT in Diffuse Large B-Cell Lymphoma

Tan Xiaoyue,Sun Xiaolin,Chen Yang,Wang Fanghu,Shang Yuxiang,Zhang Qing,Yuan Hui,Jiang Lei 대한영상의학회 2024 Korean Journal of Radiology Vol.25 No.3

Objective: We previously found that the incidence of sarcopenia increased with declining glucose metabolism of muscle in patients with treatment-naïve diffuse large B-cell lymphoma (DLBCL). This study aimed to investigate the relationship between sarcopenia and muscle glucometabolism using 18F-FDG PET/CT at baseline and end-of-treatment, analyze the changes in these parameters through treatment, and assess their prognostic values. Materials and Methods: The records of 103 patients with DLBCL (median 54 years [range, 21–76]; male:female, 50:53) were retrospectively reviewed. Skeletal muscle area at the third lumbar vertebral (L3) level was measured, and skeletal muscle index (SMI) was calculated to determine sarcopenia, defined as SMI < 44.77 cm2/m2 and < 32.50 cm2/m2 for male and female, respectively. Glucometabolic parameters of the psoas major muscle, including maximum standardized uptake value (SUVmax) and mean standardized uptake value (SUVmean), were measured at L3 as well. Their changes across treatment were also calculated as ΔSMI, ΔSUVmax, and ΔSUVmean; Δbody mass index was also calculated. Associations between SMI and the metabolic parameters were analyzed, and their associations with progression-free survival (PFS) and overall survival (OS) were identified. Results: The incidence of sarcopenia was 29.1% and 36.9% before and after treatment, respectively. SMI (P = 0.004) was lower, and sarcopenia was more frequent (P = 0.011) at end-of-treatment than at baseline. The SUVmax and SUVmean of muscle were lower (P < 0.001) in sarcopenia than in non-sarcopenia at both baseline and end-of-treatment. ΔSMI was positively correlated with ΔSUVmax of muscle (P = 0.022). Multivariable Cox regression analysis showed that sarcopenia at end-of-treatment was independently negatively associated with PFS (adjusted hazard ratio [95% confidence interval], 2.469 [1.022–5.965]), while sarcopenia at baseline was independently negatively associated with OS (5.051 [1.453–17.562]). Conclusion: Sarcopenic patients had lower muscle glucometabolism, and the muscular and metabolic changes across treatment were positively correlated. Sarcopenia at baseline and end-of-treatment was negatively associated with the prognosis of DLBCL.

Experimental and Mechanistic Understanding of Aldehyde Hydrogenation Using Au₂₅ Nanoclusters with Lewis Acids: Unique Sites for Catalytic Reactions

Li, Gao,Abroshan, Hadi,Chen, Yuxiang,Jin, Rongchao,Kim, Hyung J. American Chemical Society 2015 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.137 No.45

<P>The catalytic activity of Au<SUB>25</SUB>(SR)<SUB>18</SUB> nanoclusters (R = C<SUB>2</SUB>H<SUB>4</SUB>Ph) for the aldehyde hydrogenation reaction in the presence of a base, e.g., ammonia or pyridine, and transition-metal ions M<SUP>z+</SUP>, such as Cu<SUP>+</SUP>, Cu<SUP>2+</SUP>, Ni<SUP>2+</SUP> and Co<SUP>2+</SUP>, as a Lewis acid is studied. The addition of a Lewis acid is found to significantly promote the catalytic activity of Au<SUB>25</SUB>(SR)<SUB>18</SUB>/CeO<SUB>2</SUB> in the hydrogenation of benzaldehyde and a number of its derivatives. Matrix-assisted laser desorption ionization (MALDI) and electrospray ionization (ESI) mass spectrometry in conjunction with UV–vis spectroscopy confirm the generation of new species, Au<SUB>25-<I>n</I></SUB>(SR)<SUB>18-<I>n</I></SUB> (<I>n</I> = 1–4), in the presence of a Lewis acid. The pathways for the speciation of Au<SUB>24</SUB>(SR)<SUB>17</SUB> from its parent Au<SUB>25</SUB>(SR)<SUB>18</SUB> nanocluster as well as its structure are investigated via the density functional theory (DFT) method. The adsorption of M<SUP><I>z</I>+</SUP> onto a thiolate ligand “SR” of Au<SUB>25</SUB>(SR)<SUB>18</SUB>, followed by a stepwise detachment of “SR” and a gold atom bonded to “SR” (thus an “Au-SR” unit) is found to be the most likely mechanism for the Au<SUB>24</SUB>(SR)<SUB>17</SUB> generation. This in turn exposes the Au<SUB>13</SUB>-core of Au<SUB>24</SUB>(SR)<SUB>17</SUB> to reactants, providing an active site for the catalytic hydrogenation. DFT calculations indicate that M<SUP>z+</SUP> is also capable of adsorbing onto the Au<SUB>13</SUB>-core surface, producing a possible active metal site of a different kind to catalyze the aldehyde hydrogenation reaction. This study suggests, for the first time, that species with an open metal site like adducts [nanoparticle-M]<SUP>(<I>z</I>-1)+</SUP> or fragments Au<SUB>25-<I>n</I></SUB>(SR)<SUB>18-<I>n</I></SUB> function as the catalysts rather than the intact Au<SUB>25</SUB>(SR)<SUB>18</SUB>.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2015/jacsat.2015.137.issue-45/jacs.5b07716/production/images/medium/ja-2015-07716c_0010.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja5b07716'>ACS Electronic Supporting Info</A></P>

A Generalized Markov Chain Model for IEEE 802.11 Distributed Coordination Function

( Ping Zhong ),( Jianghong Shi ),( Yuxiang Zhuang ),( Huihuang Chen ),( Xuemin Hong ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.2

To improve the accuracy and enhance the applicability of existing models, this paper proposes a generalized Markov chain model for IEEE 802.11 Distributed Coordination Function (DCF) under the widely adopted assumption of ideal transmission channel. The IEEE 802.11 DCF is modeled by a two dimensional Markov chain, which takes into account unsaturated traffic, backoff freezing, retry limits, the difference between maximum retransmission count and maximum backoff exponent, and limited buffer size based on the M/G/1/K queuing model. We show that existing models can be treated as special cases of the proposed generalized model. Furthermore, simulation results validate the accuracy of the proposed model.

Experimental Study on the Preparation of MA@PS@Fe3O4 Phase Change Microcapsules to Inhibit the Development of Electric Branches in Epoxy Resin Cured Compounds

Liu Qian,Du Bin,Qi Wei,Mai Yuxiang,Zhao Yushun,Chen Nanqing 대한금속·재료학회 2022 ELECTRONIC MATERIALS LETTERS Vol.18 No.5

Development of electric branches caused by partial discharge leads to degradation in the performance of epoxy resin insulation materials, which seriously threatens the safe and stable operation of power equipment. In this study, n-tetradecanol (MA)@polystyrene microsphere (PS)@Fe3O4 core–shell phase change microcapsules were designed and prepared. Doping 0.1 wt% phase change microcapsular material into the epoxy resin cured compound inhibited the development of electric branches. SEM and EDS tests showed that the phase-change microcapsules had monodisperse spherical core–shell structures with an MA encapsulation rate of 24.73% and excellent phase-change thermal storage capacity. Electric field simulations revealed that Fe3O4 nanoparticles in the microcapsule shell enhanced the local field strength of the cured epoxy resin and induced the development of electric branches toward the interior of the microcapsule. Moreover, doping of microcapsules into the epoxy resin significantly slowed the rate of temperature rise and thus inhibited further development of electric branches in epoxy resin cured products. In comparison with the epoxy resin cured without microcapsules, it was found that the longitudinal and transverse lengths of electric branches were reduced by 56.6% and 69.1%, respectively, in the epoxy resin cured with 0.1 wt% MA@PS@Fe3O4 microcapsules, and the electric branch initiation field strength was increased from 0.57 to 0.68 kV/mm. This indicated that MA@PS@Fe3O4 microcapsules significantly improved the electrical branch resistance of epoxy resin cured products, and this provides a new approach for extensive applications of epoxy resin insulation materials and safe and stable operation of power equipment.