Influence of FeSe doping on superconducting properties of MgB2 by hybrid microwave method

Cheng Cheng,Zhenjie Feng,Qing Li,Xu Wang,Chuan Yu,Hao Chu,Ya Yang,Changqin Liu,Yiming Cao,Zhe Li,Jingzhe Chen,Chao Jing,Shixun Cao,Jincang Zhang 한국물리학회 2017 Current Applied Physics Vol.17 No.11

The effect of FeSe doping on the physical properties of MgB2 is studied. Bulk samples of the FeSe doped MgB2 with weight ratio x ðFeSe : MgB2Þ ¼ 0%; 3%; 7% and 10% were prepared by hybrid microwave method. It is proved that FeSe is not stable together with MgB2. Fe2þ enters into MgB2 lattice, some Mg2þ and Se2『 are combined into the new impurity compound MgSe. The superconducting transition temperature (Tc) slightly decreased with increasing doping content of FeSe from R-T and M-T curves, which results from the substitution of Mg2þ by Fe2þ in the MgB2 lattice. The Jc increase slightly with the FeSe doping content increasing from 3 wt % to 10 wt %, which results from the increasing MgSe impurity pinning centers.

An Analysis of the Ground Deformation Caused by Shield Tunnel Construction Combining an Elastic Half-Space Model and Stochastic Medium Theory

Cheng-hua Shi,Cheng-yong Cao,Ming-feng Lei 대한토목학회 2017 KSCE Journal of Civil Engineering Vol.21 No.5

The ground movement induced by the construction of shield tunnels affects the safety of nearby underground pipes and aboveground structures. Therefore, the reliable prediction of ground movement is important. In this paper, a model describing the interaction between soil and an EPB shield used in tunnels is presented, based on the classical elastic theory of Mindlin. In this model, the changing location of the working shield is considered. The equations describing the ground deformation around the tunnel caused by the additional force on the shield working surface and the frictional force between the outer surface of the shield and the surrounding soil are derived. The ground deformation caused by ground loss due to shield tunnel construction is derived using stochastic medium theory. Finally, this model is applied to two running tunnels, and the sensitivity of the ground deformation to the calculation parameters is discussed.

Mechanical Property Test and Analytical Method for Reactive Powder Concrete Columns under Eccentric Compression

Cheng-hua Shi,Min Long,Cheng-yong Cao,Guangcheng Long,Ming-feng Lei 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.4

Reactive Powder Concrete (RPC) has ultra-high strength, toughness and durability. Review studies were focused on the mechanical properties of RPC material and RPC beam. In this paper, the bearing features of RPC columns under eccentric compression with different section dimensions, reinforcement ratios, and conditions of with and without steel fibres were determined through large eccentric compression test of 22 RPC columns. The distribution patterns of stresses over the section of the RPC columns under large eccentric compression were determined under cracking loads. A simple analytical method for the cracking loads was also established. Test results revealed that the thickness ratio of elastic tensile region and the whole tensile region can be 0.4 (with steel fibres) or 0.5 (without steel fibres) when calculating the cracking loads. The tensile stress on the RPC columns showed an isosceles triangle distribution in the tensile region. A simple analytical method for calculating the ultimate loads of RPC columns under large eccentric compression was set up. Test results revealed that the equivalence coefficient of the RPC column in tensile regions can be 0.6 (with steel fibres) or 0.4 (without steel fibres). The method deduced in this paper can be used to design the RPC column under large eccentric compression.

K-doping effect of the superconductivity in K2xFeTe1-xSx (0.07 ≤ x ≤ 0.3)

Cheng Cheng,Zhenjie Feng,Qing Li,Tao Li,Qiang Hou,Fei Chen,Zhongmin Ou,Jun-Yi Ge,Shixun Cao,Jincang Zhang 한국물리학회 2019 Current Applied Physics Vol.19 No.4

Bulk samples of K doping K2xFeTe1-xSx with x=0.07, 0.1, 0.2, 0.3 are successfully prepared by using easy-to-use stable compound K2S as the reactant. The lattice constant calculated from X-ray diffraction patterns indicate that K ions enter the Fe-Te-S layers. K doping is beneficial enhance the superconductivity transition temperature from the R-T curves. The apparent diamagnetic signal is observed in M-T curves when the content of K is smaller than 0.1. However, differential curves (dM/dT) in K-rich samples appear sharp slope mutations, which means that the Meissner effect signal is covered by the increased excess ferromagnetic ions. The number of excess Fe magnetic ions is proportional to K content, which may play an important role in determining the superconductivity.

Deformation Characteristics and Countermeasures of shallow and Large-span Tunnel Under-crossing the Existing Highway in Soft Soil: a Case Study

Cheng-yong Cao,Cheng-hua Shi,Ming-feng Lei,Li-min Peng,Ruxue Bai 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.8

Hongmian Road goes under Jihe highway by the way of tunnel in Shenzhen City, Guangdong Province, China. The tunnel hassome special characteristics such as shallow depth, large span, soft soil, busy traffic, and long distance under-crossing the operatinghighway, thus there is great difficulty and risk during its construction. A series of in-situ tests were conducted to reveal deformationcharacteristics during tunneling beneath the existing highway by the double-side-drift method (DSDM). The results show that initialconstruction method and measures can't meet the safety requirement of tunnel construction, and the level of risk is extremely high, sothe construction method need to be timely adjusted. By comprehensive analysis, the double-side-drift optimum method (DSDOM) isput forward, on the basis of which a series of optimum measures also have been put forward, such as reasonable constructionmethods, the suitable length of bench and excavation, soil reinforcement measures on tunnel face, optimizing construction process,closing primary support in time and speeding up the construction of secondary lining. Then the feasibility of this optimizedconstruction method and measures are verified by the numerical simulations. Finally, from feedbacks of monitoring results, theoptimum method and measures have been proved to be reasonable and feasible, and they can guarantee a successful pass beneath theoperating highway.

Optimal Design and Dynamic Control of Construction Dewatering with the Consideration of Dewatering Process

Cheng-hua Shi,Cheng-yong Cao,Ming-feng Lei,Li-min Peng,Jing Jiang 대한토목학회 2017 KSCE Journal of Civil Engineering Vol.21 No.4

Design optimization of construction dewatering has important values in protecting the surrounding environment and reducing the engineering cost. The existing dewatering design methods are mostly based on the optimization of pumping rate needed to maintain a stable water level, while the drop and rise of water level are not considered in the estimation of pumping rate and dewatering time. The dynamics process of construction dewatering is taken into account in this article. The method for calculating the total water yield and dewatering time from the initial groundwater level to the target water level is established. Then, the design optimization of well group dewatering is provided with the consideration of total water yield and dewatering time in dynamic dewatering process. Finally, the method for the calculation of total water yield and dewatering time when dewatering regions change is derived. The proposed method can realize design optimization and dynamic control of dewatering as the dewatering regions and water level changes in construction. The reliability of this method is verified in on-site engineering applications.

Research on the Coupling Coordinated Development Evaluation of Digital Finance and Industrial Structure Upgrading

조성철 ( Cheng-zhe Cao ),손양 ( Yang Sun ),고려아 ( Li-ya Gao ) 한중사회과학학회 2024 한중사회과학연구 Vol.22 No.2

중국의 고품질경제발전이라는 배경 하에서 디지털 기술을 기반으로 한 금융산업과 산업구조 향상의 심층 융합이 중심이 되고 있다. 본 연구는 엔트로피 가중치를 이용하여 2011∼2021년 사이 중국 31개 성의 패널데이터를 바탕으로 중국 디지털금융 발전 수준 및 산업구조 향상수준을 측정하였다. 또 결합조화도 모형으로 양자 간의 결합조화 정도 및 각 지역별 차이를 분석하였다. 첫째, 발전수준 측정 결과에 의하면 중국 디지털금융 발전수준은 0.8을 넘어 비교적 높은 수준을 유지하고 있는 반면에 공업 장기발전의 낙후성으로 인한 산업구조 향상수준은 0.45정도로 비교적 낮은 수준을 유지하였다. 둘째, 경제 발전수준의 차이가 비교적 크기 때문에 지역 간 디지털금융 발전수준 및 산업구조 향상에서는 ‘동부-강’, ‘중부-안정’, ‘서부-약’의 모습이 존재하였다. 그 밖에도 두 시스템의 결합조화도모형 측정 결과에 의하면, 중국 디지털금융과 산업구조 향상의 결합도는 미결합 단계이며, 조화 정도는 양호한(양성) 조화 단계이며, 결합조화도는 초급 수준이다. 셋째, 디지털금융 및 산업구조향상의 발전수준과 동일하게 결합 조화도모형도 지역별로 이질적인 경향이 분명하게 존재하여,’동부-강 ‘,’중부-안정 ‘,’서부 약 ‘의 결과를 보여주었다. 마지막으로, 위의 결론을 바탕으로 디지털 기술을 적극적으로 개발하고, 디지털금융과 산업구조향상의 결합조화발전으로 중국 경제의 고품질발전을 실현하기 위한 건설적인 정책 의견을 제시한다. In the context of high-quality economic development, the deep integration of the financial industry empowered by digital technology and industrial structure upgrading has become a focus. The article uses the entropy weight method and panel data from 31 provinces and cities in China from 2011 to 2021 to calculate the level of digital finance development and industrial structure upgrading in China. Then, the coupling coordination degree model is used to analyze the degree of coupling coordination development between the two. Of course, this also includes the differences in coupling coordination in different regions. The measurement results of development level show that the development level of digital finance in China has exceeded 0.8, maintaining a relatively high level. On the contrary, due to the long-term lag in industrial development, the level of industrial structure upgrading is relatively low, maintained at around 0.45. Secondly, due to the significant differences in economic development levels, there is also a situation where the level of digital finance development and industrial structure upgrading between regions are strong in the east, stable in the middle, and weak in the west. In addition, the measurement results of the coupling coordination model of the two systems show that the coupling degree between China’s digital finance and industrial structure upgrading is in the under coupling stage, the coordination degree is in the benign coordination stage, and the coupling coordination degree is at the primary coordination level. Secondly, consistent with the level of development of digital finance and industrial structure upgrading, the coupled coordination model also exhibits a clear regional heterogeneity trend, which is manifested as the result of strong in the east, stable in the middle, and weak in the west. Finally, based on the above conclusions, it is proposed to vigorously develop digital technology, promote the coupling coordinated development of digital finance and industrial structure upgrading, and provide constructive policy suggestions for achieving high-quality development of the Chinese economy.

Development of Multidirectional Nonlinear Numerical Wave Tank by Naoe-FOAM-SJTU Solver

Cao, Hong-Jian,Wan, De-Cheng Korean Society of Ocean Engineers 2014 International journal of ocean system engineering Vol.4 No.1

A three-dimensional multidirectional nonlinear numerical wave tank (NWT) based on the Navier-Stokes equations and the Finite Volume Method (FVM) is developed by using the two-phase hydrodynamic flow solver naoe-FOAM-SJTU based on the open source toolbox OpenFOAM. The free surface is capturing with the Volume Of Fluids (VOF). The directional wave including Stokes wave, solitary wave and nonlinear wave are simulated and verified. The multi-directional waves are also simulated with particular wave spectral such as JONSWAP and wave directional spreading function. The obtained numerical results show the capability of the solver to generate different type of multidirectional nonlinear waves accurately. Meanwhile, it implies that the presented NWT can easily extend to model the wave-structures interactions, which will be great help to the offshore structures design.

Transcriptome sequencing provides insights into the metabolic pathways of patchouli alcohol and pogostone in Pogostemon cablin (Blanco) Benth

Cheng Peng,Yang He,Cao Deng,Liang Xiong,Shishang Qin 한국유전학회 2016 Genes & Genomics Vol.38 No.11

Pogostemon cablin (Blanco) Benth. is an important medicinal plant; however, its molecular biology remains largely unexplored. Here, we report the results of whole transcriptome-wide analyses of P. cablin using nextgeneration sequencing technology. In the present study, we generated 108,996 unigenes using RNA sequencing data. Among these unigenes, 65,536 were annotated in the NR database. There were 40,670 intact open reading frames (ORFs), which accounted for 69 % of the 58,820 predicted ORFs, demonstrating that our assembled transcriptome was of high quality. Gene expression levels in the leaf and stem were quantified, and 18,481 unigenes (17 %) were determined to be significantly differentially expressed. The patchouli alcohol (PA) and pogostone (PO) metabolic pathway of P. cablin was also reconstructed, and among the 17 putative homologs to PA and PO biosynthesis-related genes, seven were significantly upregulated in the stems, and three genes were significantly upregulated in the leaves. The correlation between the essential oil contents of P. cablin and the potentially pivotal genes for PA and PO production were identified. Considering that the contents of PA and PO in leaves and stems are markedly different in the same plant and we did not detect any pattern in the expression levels of candidate genes between leaves and stems, we speculate that after the biosynthesis, more PA probably accumulates in the leaves, and more PO in the stems of P. cablin. The transcriptome of P. cabin will facilitate further researches on the molecular system biology of the Pogostemon genus, as well as the in-depth studyies of PA and PO biosynthesis and its potential applications for genetic engineering.

SCATTERING CORRECTION FOR IMAGE RECONSTRUCTION IN FLASH RADIOGRAPHY

Cao, Liangzhi,Wang, Mengqi,Wu, Hongchun,Liu, Zhouyu,Cheng, Yuxiong,Zhang, Hongbo Korean Nuclear Society 2013 Nuclear Engineering and Technology Vol.45 No.4

Scattered photons cause blurring and distortions in flash radiography, reducing the accuracy of image reconstruction significantly. The effect of the scattered photons is taken into account and an iterative deduction of the scattered photons is proposed to amend the scattering effect for image restoration. In order to deduct the scattering contribution, the flux of scattered photons is estimated as the sum of two components. The single scattered component is calculated accurately together with the uncollided flux along the characteristic ray, while the multiple scattered component is evaluated using correction coefficients pre-obtained from Monte Carlo simulations.The arbitrary geometry pretreatment and ray tracing are carried out based on the customization of AutoCAD. With the above model, an Iterative Procedure for image restORation code, IPOR, is developed. Numerical results demonstrate that the IPOR code is much more accurate than the direct reconstruction solution without scattering correction and it has a very high computational efficiency.