Late Ordovician provenance and depositional setting in the southwestern Ordos Block, China: constraints from zircon U-Pb geochronology

Fu Yang,Gang Chen,Yu Kang,Dongmin Ma,Qilin Chen,Tian Tao,Fu Deliang 한국지질과학협의회 2020 Geosciences Journal Vol.24 No.2

The U-Pb ages of single zircon grains contained in the sandstone samples were analyzed by the LA-ICP-MS method, the sediment provenances and geological significance were discussed. The LA-ICP-MS zircon U-Pb dating from the sandstones, tuffaceous sandstones and volcanic tuffs of the Pingliang and Zhaolaoyu Formations along the southwestern Ordos Block are used to limit the maximum depositional age and material sources. The results show that: (1) The youngest ages of zircon dating in the three samples are 445 Ma, 444 Ma and 443 Ma, respectively, suggesting that the studied Formations were deposited in the Late Ordovician. (2) The detrital zircon U-Pb age analysis of the sandstones sample from the Pinliang Formation clustered in the 445–477 Ma, 588–1548 Ma and 1612–2496 Ma with the corresponding youngest peak age of 454.5 ± 3.3 Ma. (3) The distribution of zircon U-Pb age in sandstone samples showing that the sedimentary rocks detritus was mainly sourced from the North Qinling-Qilian terranes and the NCC, and has double provenance supply in the north and south. The material source of the tuffaceous sandstones and volcanic tuffs mainly comes from the volcanic and magmatic activity related to the North Qilian-North Qinling Island Arcs.

Covalent Confinement of Sulfur Copolymers onto Graphene Sheets Affords Ultrastable Lithium-Sulfur Batteries with Fast Cathode Kinetics

Ma, Junpeng,Fan, Jingbiao,Chen, Shang,Yang, Xinyue,Hui, Kwun Nam,Zhang, Hongwen,Bielawski, Christopher W.,Geng, Jianxin American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.14

<P>Lithium-sulfur (Li-S) batteries have received significant attention due to the high theoretical specific capacity of sulfur (1675 mA h g<SUP>-1</SUP>). However, the practical applications are often handicapped by sluggish electrochemical kinetics and the “shuttle effect” of electrochemical intermediate polysulfides. Herein, we propose an in-situ copolymerization strategy for covalently confining a sulfur-containing copolymer onto reduced graphene oxide (RGO) to overcome the aforementioned challenges. The copolymerization was performed by heating elemental sulfur and isopropenylphenyl-functionalized RGO to afford a sulfur-containing copolymer, that is, RGO-<I>g</I>-poly(S-<I>r</I>-IDBI), which is featured by a high sulfur content and uniform distribution of the poly(S-<I>r</I>-IDBI) on RGO sheets. The covalent confinement of poly(S-<I>r</I>-IDBI) onto RGO sheets not only enhances the Li<SUP>+</SUP> diffusion coefficients by nearly 1 order of magnitude, but also improves the mechanical properties of the cathodes and suppresses the shuttle effect of polysulfides. As a result, the RGO-<I>g</I>-poly(S-<I>r</I>-IDBI) cathode exhibits an enhanced sulfur utilization rate (10% higher than that of an elemental sulfur cathode at 0.1C), an improved rate capacity (688 mA h g<SUP>-1</SUP> for the RGO-<I>g</I>-poly(S-<I>r</I>-IDBI) cathode vs 400 mA h g<SUP>-1</SUP> for an elemental sulfur cathode at 1C), and a high cycling stability (a capacity decay of 0.021% per cycle, less than one-tenth of that measured for an elemental sulfur cathode).</P> [FIG OMISSION]</BR>

Experimental Feasibility Research on a High-efficiency Cement-based Clay Stabilizer

Ma Cong,Chen Bing,Chen Longzhu 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.1

In many civil engineering constructions, soft clayey soils are often stabilized with Ordinary Portland Cement (OPC) whose production process is energy intensive and emits a large quantity of CO2. In this paper, an OPC-based clay stabilizer (CSCN) which contains some eco-friendly materials is studied to compare with OPC by investigating the mechanical properties of the stabilized clays. Microstructural and mineralogical studies using Scanning Electron Microscope (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) are performed to reveal the mechanisms controlling the development of the strength and modulus. The test results indicate that the compressive strength and secant modulus increase with increasing the content of CSCN and curing age. To achieve the equivalent improvement of the strength and modulus, much less CSCN is needed relative to OPC, which illustrates that CSCN can be a more effective and relatively eco-friendly clay stabilizer. The analysis on pH values and moisture consumption indicates that the hydration and pozzolanic reactions in CSCN-stabilized clays may be quicker than those in OPC-stabilized clays. The microstructural analyses confirm the formation of C-S-H gels in stabilized clays and the types of C-S-H gels are dependent upon the Ca/Si molar ratio according to EDX results. The types and amounts of new minerals in stabilized clays are the possible mechanisms controlling the enhancement of mechanical properties.

China Consensus Document on Allergy Diagnostics

Chen Hao,Li Jing,Cheng Lei,Gao Zhongshan,Lin Xiaoping,Zhu Rongfei,Yang Lin,Tao Ailin,Hong Haiyu,Tang Wei,Guo Yinshi,Huang Huaiqiu,Sun Jinlyu,Lai He,Lei Cheng,Liu Guanghui,Xiang Li,Chen Zhuanggui,Ma Ha 대한천식알레르기학회 2021 Allergy, Asthma & Immunology Research Vol.13 No.2

The prevalence of allergic diseases has increased dramatically in recent years in China, affecting the quality of life in 40% of the population. The identification of allergens is the key to the diagnosis of allergic diseases. Presently, several methods of allergy diagnostics are available in China, but they have not been standardized. Additionally, cross-sensitization and co-sensitization make allergy diagnostics even more complicated. Based on 4 aspects of allergic disease (mechanism, diagnosis procedures, allergen detection in vivo and in vitro as well as the distribution map of the most important airborne allergens in China) and by referring to the consensus of the European Society of Allergy and Clinical Immunology, the World Allergy Organization, and the important literature on allergy diagnostics in China in recent years, we drafted this consensus of allergy diagnostics with Chinese characteristics. It aims to standardize the diagnostic methods of allergens and provides a reference for health care givers. The current document was prepared by a panel of experts from the main stream of professional allergy associations in China.

Inter- and Intralayer Compression of Germanane

Ma, Yanmei,Chen, Yuanzheng,Ma, Yanming,Jiang, Shishi,Goldberger, Josh,Vogt, Thomas,Lee, Yongjae American Chemical Society 2014 JOURNAL OF PHYSICAL CHEMISTRY C - Vol.118 No.48

<P>The inter- and intralayer compression in germanane (GeH) were investigated at room temperature and pressures up to 10 GPa using a diamond-anvil cell (DAC) in combination with X-ray diffraction and micro-Raman spectroscopy. To examine the effect of the pressure-transmitting medium (PTM) on the interlayer compression leading to a possible insertion and exfoliation, two separate experiments were performed using water as PTM and no PTM. The results indicate that both the inter- and intralayer compression are dependent on the PMT, and the linear compressibility is 0.0274(1) and 0.0031(9) GPa<SUP>–1</SUP> along the <I>c</I>- and <I>a</I>-axis based on the shifts of the (002) and (100) reflections for water PTM, and 0.0190(6) and 0.0026(9) GPa<SUP>–1</SUP> along the <I>c</I>- and <I>a</I>-axis when pressurizing without PTM. High-pressure Raman spectra indicate that the intralayer Ge–Ge stretching mode is also dependent on the PMT. It exhibits a blue-shift of 3.01 and 2.66 cm<SUP>–1</SUP>/GPa when using water as PTM and without PTM, respectively. The equation of state determined from our experiments yields a bulk modulus of 9.6(2) GPa with <I>B</I>′<SUB>0</SUB> = 12 for GeH. Theoretical calculations were performed to understand the pressure dependence on the electronic band structure and the observed Raman spectrum.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2014/jpccck.2014.118.issue-48/jp507503j/production/images/medium/jp-2014-07503j_0008.gif'></P>

Numerical analysis of a dual-wave band guided-mode resonance filter with embedded bilayer asymmetric metallic gratings

Ma Wen-Zhuang,Liu Jing,Yu Gao-Xiang,Chen Wei,Chen Yu-Shan,Deng Xu-Chu 한국물리학회 2021 Current Applied Physics Vol.27 No.-

In this paper, a novel guided-mode resonances (GMRs) based embedded dual-wavelength filter, which had the bilayer gratings located at the two sides of dielectric substrate and arranged at asymmetric position, was investigated and studied theoretically. As compared to symmetric structures that usually provided single wavelength of transmission resonance, as one normal incidence was used for transverse magnetic polarized light, the designed asymmetric structure could generate two remarkable narrow band wavelengths of transmission resonance. The parameters to affect the resonance wavelengths and the transmission resonance Q value (Q = λ/Δλ) of two bands were the distance between the two metallic gratings, the relatively lateral positions of the upper and lower gratings, the number of structure period, the thicknesses of metallic gratings, and the thickness of dielectric film. By optimizing the designed parameters, a GMR device with two resonance wavelengths located at 1239 and 1302 nm showed relative optimal performance because they had high transmission depth (99.9% and 90%) and ultra-narrow transmission bandwidth (2.8 and 1.8 nm) at the two resonance wavelengths. The presented structure can offer a potential route towards dual-band narrow-band filters and refractive index sensors in the near infrared.

잠재요인 모델 기반 영화 추천 시스템

Chen Ma,김강철(Kang-Chul Kim) 한국전자통신학회 2021 한국전자통신학회 논문지 Vol.16 No.1

영화 산업의 빠른 발전으로 영화의 제작 수가 급격하게 증가하고 있으며, 영화 추천 시스템은 관객들의 과거 행동이나 영화 후기에 기반하여 관객들의 선호도를 예측하여 영화의 선택에 도움을 주고 있다. 본 논문은 평점의 평균과 편향의 보정을 이용하여 잠재요인 모델에 기반한 영화 추천 시스템을 제안한다. 특이값 분해 방법이 평점 매트릭스 분해에 사용되고, 통계 경사 하강법이 최소자승 손실 함수의 파라미터 최적합에 사용된 다. 그리고 평균 제곱근 오차를 사용하여 제안한 시스템 성능을 평가한다. Surprise 패키지를 이용하여 제안한 시스템을 구현 하였으며, 모의실험 결과는 평균 제곱근 오차가 0.671이며, 다른 논문에서 방법에 비하여 좋은 성능을 가진다는 것을 확인하였다. With the rapid development of the film industry, the number of films is significantly increasing and movie recommendation system can help user to predict the preferences of users based on their past behavior or feedback. This paper proposes a movie recommendation system based on the latent factor model with the adjustment of mean and bias in rating. Singular value decomposition is used to decompose the rating matrix and stochastic gradient descent is used to optimize the parameters for least-square loss function. And root mean square error is used to evaluate the performance of the proposed system. We implement the proposed system with Surprise package. The simulation results shows that root mean square error is 0.671 and the proposed system has good performance compared to other papers.

Monitoring Soil and Vegetable Quality under Six Fertilization Strategies in Organic and Conventional Farming Systems

Ma, C.H.,Chen, J.H.,Yang, R.Y.,Palada, M.C.,Ou, S.C.,Lin, Y.H.,Chen, L.H. 한국토양비료학회 2009 한국토양비료학회 학술발표회 초록집 Vol.2009 No.10

Graphitization of graphene oxide films under pressure

Chen, Xianjue,Deng, Xiaomei,Kim, Na Yeon,Wang, Yu,Huang, Yuan,Peng, Li,Huang, Ming,Zhang, Xu,Chen, Xiong,Luo, Da,Wang, Bin,Wu, Xiaozhong,Ma, Yufei,Lee, Zonghoon,Ruoff, Rodney S. Elsevier 2018 Carbon Vol.132 No.-

<P><B>Abstract</B></P> <P>Lightweight, flexible graphite foils that are chemically inert, high-temperature resistant, and highly electrically and thermally conductive can be used as component materials in numerous applications. “Graphenic” foils can be prepared by thermally transforming graphene oxide films. For this transformation, it is desirable to maintain a densely packed film structure at high heating rates as well as to lower the graphitizing temperatures. In this work, we discuss the pressure-assisted thermal decomposition of graphene oxide films by hot pressing at different temperatures (<I>i.e.</I>, 300 °C, 1000 °C, or 2000 °C). The films pressed at 1000 °C or 2000 °C were subsequently heated at 2750 °C to achieve a higher degree of graphitization. The combination of heating and pressing promotes the simultaneous thermal decomposition and graphitic transformation of G-O films. Films pressed at 2000 °C as well as films further graphitized at 2750 °C show high chemical purity, uniformity, and retain their flexibility. For films pressed at 2000 °C and then further heated at 2750 °C, the mechanical performances outperform the reported values of the “graphite” foils prepared by calendering exfoliated graphite flakes; the electrical conductivity is ∼3.1 × 10<SUP>5</SUP> S/m and the in-plane thermal conductivity is ∼1.2 × 10<SUP>3</SUP> W/(m·K).</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effect of Thyroid Hormone on the Gene Expression of Myostatin in Rat Skeletal Muscle

Ma, Yi,Chen, Xiaoqiang,Li, Qing,An, Xiaorong,Chen, Yongfu Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.2

Modification of thyroid hormone levels has a profound effect on skeletal muscle differentiation, predominantly through direct regulation involving thyroid hormone receptors. Nevertheless, little is known about the regulation of myostatin gene expression in skeletal muscle due to altered concentrations of thyroid hormone. Thus, the goal of our study was to find out whether altered thyroid states could change the gene expression of myostatin, the most powerful inhibitor of skeletal muscle development. A hyperthyroid state was induced in rats by daily injections of L-thyroxine 20 mg/100 g body weight for 14 days, while a hypothyroid state was induced in another group of rats by administering methimazole (0.04%) in drinking water for 14 days. After a period of 14 days of L-thyroxine treatment we observed a significant increase of myostatin expression both in mRNA and protein level. However, decreased expression of myostatin mRNA and protein were observed in hypothyroid rats. Furthermore, our studies demonstrated that the upregulation of myostatin gene expression might be responsible for the loss of body weight induced by altered thyroid hormone levels. We concluded that myostatin played a role in a metabolic process in muscle that was regulated by thyroid hormone.