Effect of pre-existing faults on the distribution of lower crust exhumation under extension: numerical modelling and implications for NW Ghana

Xiaojun Feng,Enyuan Wang,Prince O. Amponsah,Jérôme Ganne,Roland Martin,Mark W. Jessell 한국지질과학협의회 2019 Geosciences Journal Vol.23 No.6

3D thermo-mechanical models have been constructed to explore the influence of pre-existing faults on the temporalspatial distribution of high-grade amphibolite-granulite facies metamorphic rocks during extension. The different dip amounts of three pre-existing faults (refer to the Bole-Nangodi shear zones, the Jirapa shear zone and the Bulenga shear zone in the study area) are studied in models. The results show the lower crust exhumes occur at a relatively low rate prior to attaining a Stretching Factor = 4.2%. The partially molten lower crustal rocks tend to move (up to 20 km) towards the center of the model and focus exhumation in regions where pre-existing faults intersect. The high-strain corridors in models are used to understand the loci of exhumation in the Bole-Bulenga domain of NW Ghana. Accordingly, in the eastern and western parts of the high-grade rock corridors in NW Ghana, partially molten rocks exhumed from the lower into middle-upper crustal levels are interpreted to have been dominantly facilitated by the km-scale high-strain corridors. In the central part of the Bole-Bulenga domain, the high-grade rocks are interpreted to have been exhumed because of a coupling between two mechanisms: (1) The exhumation of partially molten rocks between the Jirapa and Bole-Nangodi faults increases in spatially due to the reduction in space from north to south. (2) The exhumation of lower partially molten rocks in the central part, as a result of inherited orthogonal (E-W) structures.

The exhumation along the Kenyase and Ketesso shear zones in the Sefwi terrane, West African Craton: a numerical study

Xiaojun Feng,Enyuan Wang,Jérôme Ganne,Roland Martin,Mark Jessell 한국지질과학협의회 2019 Geosciences Journal Vol.23 No.3

High-grade (amphibolite–granulite facies) tectono-metamorphic domains in the Sefwi terrane of Ghana are separated from adjacent lower-grade (greenschist facies) greenstone belts by two main shear zones. The high-grade rocks presumably exhumed along the sinistral shear zones during the D2 ENE-WSW transtension (~2073 Ma). To better understand the role boundary conditions and the spatial relationship of faults play in the exhumation of partially molten lower crust in the Sefwi terrane, ten 3D thermomechanical models have been constructed. The results show that the normal component of velocity boundary conditions mainly controls the exhumation (8–10 km) of the lower crust along pre-existing faults, while the exhumation in the relay zones between faults is controlled by the obliquity between the applied extensional velocity vector and the vertical wall on which it is applied. The strike of the exhumation belt made of partially molten lower crust rocks in the relay zone is sub-orthogonal to the horizontal maximum stretching axis. The isostatic compensation from low-density upper mantle to overlying crust (thinning) is higher under transtension than under extension. The lower crust exhumation influenced by inherited shear zones (ductile) can be used to better understand the loci of the high-grade rocks in the Sefwi terrane. We suggest that the Kukuom-Juaboso domain composed of amphibolite–migmatite facies rocks probably resulted from the concentration of partially molten rocks in the relay zone between the Ketesso and Kenyase shear zones during the D2 ENE-WSW transtension. The two shear zones probably underwent two main stages for growth and maturation from the D1 to D2 phases. The regional exhumation of the high-grade rocks in the Sefwi terrane probably occurred within < 5 Ma.

Light-induced negative differential resistance effect in a resistive switching memory device

Xiaojun Wang,Yuanyang Wang,Ming Feng,Kaiyue Wang,Pinbo Bai,Yuming Tian 한국물리학회 2020 Current Applied Physics Vol.20 No.3

The negative differential resistance (NDR) effect was observed in a Pt/BiFeO3/TiO2/BiFeO3/Pt memory cell by using light-illumination as extra stimulation. Further, the coexistence appearances and gradually becomes obvious when the device is exposed to light-illumination, which display an excellent stability and reversibility of the coexistence of NDR and resistive switching (RS) at room temperature. Through analysis of the physical conduction mechanism, it is expected that a large number of photo-generated charge carriers are induced under light-illumination on the surface and interface of the heterojunction is responsible for the appearance of this coexistence phenomenon. Importantly, the NDR effect is strengthened by the competition transfer of charge carrier in the polarized electric field under light-illumination. This work shows that the coexistence of lightmodulated NDR and RS can deeply explore the potential applications of light-controlled multifunctional devices.

FORMATION OF REVERSED MICELLE NANORING BY A DESIGNED SURFACTANT-LIKE PEPTIDE

FENG QIU,YONGZHU CHEN,CHENGKANG TANG,YANRONG LU,XIAOJUN ZHAO,JINGQIU CHENG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2012 NANO Vol.7 No.4

Designing self-assembling peptides as nanomaterials has been an attractive strategy in recent years, however, these peptides were usually studied in aqueous solutions for their self-assembling behaviors and applications. In this study, we have designed a surfactant-like peptide AGD with a wedge-like shape and studied its self-assembling behaviors in aqueous solution or nonpolar system. By analyzing the intermolecular hydrogen bond using FT-IR and characterizing the nanostructures with DLS, AFM and TEM, it was con¯rmed that AGD could not undergo selfassembly in aqueous solution while could self-assemble into well-ordered nanorings in nonpolar system. A molecular model has been proposed to explain how the nanorings were formed in the manner of reversed micelle. These results suggested a novel strategy to fabricate self-assembling peptide nanomaterials in nonpolar system, which could have potential applications in many ¯elds.

A triage strategy in advanced ovarian cancer management based on multiple predictive models for R0 resection: a prospective cohort study

Zheng Feng,Hao Wen,Zhaoxia Jiang,Shuai Liu,Xingzhu Ju,Xiaojun Chen,Lingfang Xia,Junyan Xu,Rui Bi,Xiaohua Wu 대한부인종양학회 2018 Journal of Gynecologic Oncology Vol.29 No.5

Objective: To present the surgical outcomes of advanced epithelial ovarian cancer (AEOC) since the implementation of a personalized approach and to validate multiple predictive models for R0 resection. Methods: Personalized strategies included: 1) Non-invasive model: preoperative clinico-radiological assessment according to Suidan criteria with a predictive score for all individuals. Patients with a score 0–2 were recommended for primary debulking surgery (PDS, group A), or otherwise were counseled on the choices of PDS, neoadjuvant chemotherapy (NAC, group B) or staging laparoscopy (S-LPS). 2) Minimally invasive model: S-LPS with a predictive index value (PIV) according to Fagotti. Individuals with a PIV <8 underwent PDS (group C) or otherwise received NAC (group D). Intraoperative assessment (with Eisenkop, peritoneal cancer index [PCI], and Aletti scores) and surgical results were prospectively collected. Results: Between September 2015 and August 2017, 161 pathologically confirmed epithelial ovarian cancer patients were included. A total of 52 (32.3%) patients had a predictive score of 0–2, and 109 (67.7%) patients had a score ≥3. Among these individuals, 41 (25.5%) patients received S-LPS. Finally, 110 (68.3%) patients underwent PDS (A+C), and 51 (31.7%) patients received NAC (B+D). The R0 resection rates in PDS and NAC patients were 56.4% and 60.8%, respectively. The area under the curve (AUC) of Suidan criteria was 0.548 for group (A+C). The AUC of Fagotti score was 0.702 for group C. The AUC of Eisenkop, PCI, and Aletti scores were 0.808, 0.797, and 0.524, respectively. Conclusion: The Suidan criteria were not effective in these AEOC patients. S-LPS was helpful in decision-making for PDS and should be endorsed in the future.

Synthesis of a new polystyrene@Fe3O4 magnetic microspheres

Yongping Xue,Feng Jian,Xuewen Zhong,Lu Tang,Xiaojun Yang 한양대학교 세라믹연구소 2021 Journal of Ceramic Processing Research Vol.22 No.4

In this article, the synthesis process of magnetic polystyrene@Fe3O4 was investigated, which are suitable for the applicationin magnetically stabilized fluidized-bed reactors. The magnetic polystyrene@Fe3O4 coated with Fe3O4 were prepared bysuspension polymerization. In the reaction, triethoxy(vinyl)silane, styrene, divinylbenzene, liquid paraffin, gelatin, benzoylperoxides (BPO) were used as the surfactant, monomers, the crosslinking agent, a porogenic agent, a dispersant, an initiator,respectively. Simultaneously, the chemical composition, morphologies, particle sizes, the amount of Fe3O4 coated were analyzed. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy(FTIR), vibrating sample magnetometer (VSM) analysis and thermo gravimetric analysis (TGA). The results showed that thenew type of magnetic polystyrene@Fe3O4 microspheres were porous, spherical in shape with a narrow particle size distributionin the range of 150~200 μm. The amount of Fe3O4 coating reached to 12.39%, and the maximum saturation magnetizationwas 51.71 A·m2·kg-1 at room temperature. In addition, the results also showed that polystyrene@Fe3O4 magnetic microsphereshave good acid resistance and good suspendability.

Horizontal Thinking vs Vertical Thinking: A Comparison between Chinese and Western Philosophical Counseling based on Socrates and Confucius

Yueyao Ma,Xiaojun Ding,Feng Yu 강원대학교 인문과학연구소 2021 Journal of Humanities Therapy Vol.12 No.2

Similar to the First and Second problematics distinction of thinking figured out by Hall and Ames (1995), we further propose two modes of thinking, i.e., horizontal thinking and vertical thinking, which can also be defined as analogical/correlative thinking and causal thinking. When being extended to the field of philosophical research, they can be used to manifest the differences between Chinese and Western philosophical thinking. Philosophical counseling is an emerging activity which attempts to make the academic and theoretical philosophy more practical and helpful in people’s daily life. Focusing on Chinese thinking (horizontal thinking) and Western thinking (vertical thinking), we analyze the differences between philosophical counseling in the East and West under different modes of thinking from the general to the specific in logical sequences. We especially select Socratic dialogue and Confucius’ heuristic teaching as epitomes of Western and Chinese thinking, in order to explore the possibility of combining the two together and search for an appropriate localization approach to philosophical counseling in China.

Sputum Autoantibodies Are More Relevant in Autoimmune Responses in Asthma than Are Serum Autoantibodies

Rundong Qin,Fei Long,Xiaojun Xiao,Jing Xiao,Zhengyu Zheng,Mulin Feng,Renbin Huang,Tao Peng,Jing Li 대한천식알레르기학회 2019 Allergy, Asthma & Immunology Research Vol.11 No.3

Purpose: The data on the differences between sputum autoantibodies (Sp-Abs) and serum autoantibodies (Se-Abs) in reflection of autoimmune responses to lungs is still lacking. Methods: Ten types of Abs were investigated in matched Se and Sp samples collected from recruited subjects. Correlations between Ab levels and airway inflammatory parameters and measures of pulmonary function were assessed. The network-based and inter-correlated analysis was performed to explore the patterns of Sp- and Se-Ab profiles. Results: Fifty stable asthmatic patients and 24 healthy volunteers were recruited for our study, 15 with mild asthma, 18 with moderate asthma and 17 with severe asthma. The concentrations of Sp-Ab against U1 small nuclear ribonucleoprotein (Sp-anti-U1-SnRNP), Sp-Ab against Smith antigen and Se-Ab against thyroid peroxidase (anti-TPO) in severe asthmatics and Sp-anti-U1-SnRNP in moderate asthmatics were significantly higher compared to healthy controls and mild asthmatic subjects (P < 0.05). Sp-anti-U1-SnRNP levels were positively correlated with the dose of inhaled corticosteroids, Sp eosinophil counts and fractional exhaled nitric oxide (r = 0.326, P = 0.022; r = 0.356, P = 0.012; r = 0.241, P = 0.025, respectively) and negatively correlated with Sp neutrophil counts (r = −0.308, P = 0.031) with adjustment for age. Spearman's correlation matrix showed multiple inter-correlations among Sp-Abs and Se-Abs (P < 0.05) while only the levels of Ab against DNA topoisomerase and anti-TPO in Se were correlated with those Sp-Ab counterparts (P < 0.05). The network-based analysis defined 2 clusters: clusters 1 and 2 contained 10 Sp-Abs and 10 Se-Abs, respectively. Conclusions: This study observes that Sp-Abs are more associated with clinical parameters and the severity of disease in asthma compared to Se-Abs. Targeting on Sp-Abs which are the hallmark of the localized autoimmune event might help us better understand the role of autoimmunity in the pathological mechanism of asthma. Keywords: Asthma; autoimmunity; autoantibodies; sputum; se

Ultrafast UV Switch Based on ZnO-Ag Heterostructures

XIU-YUN AN,Feng Teng,Zhenxing Zhang,Xiaojun Pan,Jinyuan Zhou,ER-QING XIE 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.1

ZnO-silver (Ag) heterostructure nanoparticle films were prepared by spin-coating, followed by annealing at 700°C for 2 h. The films were then used as UV photodetector which show high photoresponse. The heterostructure-film device displayed an ultrafast decay time of 18 ms and a rise time of 50 ms upon ultraviolet irradiation. Additionally, the time-dependent photocurrent upon UV switching reveals a rectangularly shaped profile, rarely reported in previous literature. The highly improved photoresponse properties of ZnO-Ag heterostructure-film device could be attributed to the Schottky barrier height (SBH) and depletion width reduction from the embedded Ag nanoclusters. Compared to a pure ZnO film, both the responsivity (Rλ) and external quantum efficiency (EQE) of the ZnO-Ag heterostructure-film photodetectors were improved more than 13-fold. This research provides a promising strategy for fabricating UV-photodetectors with ultrafast response.

An experimental study on the cavitation vibration characteristics of a centrifugal pump at normal flow rate

Yi Li,Guangwei Feng,Xiaojun Li,Qiaorui Si,ZuChao Zhu 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.10

Cavitation is a challenging flow abnormality that leads to undesirable effects on the energy performance of the centrifugal pump and the reliable operation of the pump system. The onset and mechanism of a phenomenon that results in unsteady cavitation must be realised to ensure a reliable operation of pumps under the cavitation state. This study focuses on cavitation instability at normal flow rate, at which point the unsteady cavitation occurs as the available net positive suction head (NPSHa) falls below 5.61 m for the researched pump. An ameliorative algorithm–united algorithm for cavitation vibration analysis is proposed on the basis of short time Fourier transform (STFT) and Wigner–Ville distribution (WVD). The STFT–WVD method is then tested using vibration data measured from the centrifugal pump. The relationship between vibration and suction performance indicates that the inception and development of cavitation can be effectively detected by the distribution and intensity of the united algorithm at the testing points. Intermediate frequency components at approximately 6 kHz fluctuate initially with the development of cavitation. A time–frequency characteristic is found to be conducive to monitoring the cavitation performance of centrifugal pumps.