Synergistic Enhancement of the Strength-Ductility for Stir Casting SiCp/2024Al Composites by Two-Step Deformation

Fu‑xiang Cao,Kun‑kun Deng,Cui‑ju Wang,Kai‑bo Nie,Wei Liang,Jian‑feng Fan 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.12

The 10 μm 10 vol% SiCp/2024Al composites sheet was successfully fabricated by semi-solid stir casting followed withtwo-step deformation (extrusion and rolling). The two-step thermal deformation solves the sheet rolling formability of theSiCp/2024Al composites produced by stir casting. Compared with the SiCp/2024Al composites prepared by traditional powdermetallurgy, this paper innovatively studied the synergistic enhancement between CuAl2phase and SiCpon the mechanicalproperties. The result shows that the two-step deformation can significantly improve the uniformity of the distribution of SiCpand CuAl2phases. At the same time, the average size of the SiCpand CuAl2phase decreases after the two-step deformation. During the hot extrusion, SiCphas an obvious hindrance to the refinement of the CuAl2phase. Moreover, the SiCp/2024Alcomposites sheet exhibits excellent yield strength (295 MPa), ultimate tensile strength (489 MPa), and elongation (10.42%). The performance improvement of SiCp/2024Al after two-step thermal deformation is mainly attributed to the improvedinterface bonding strength of SiCp-2024 Al matrix, the refined SiCpand the more uniform distribution of SiCp.

Subcellular Characterization of Porcine Oocytes with Different Glucose-6-phosphate Dehydrogenase Activities

Fu, Bo,Ren, Liang,Liu, Di,Ma, Jian-Zhang,An, Tie-Zhu,Yang, Xiu-Qin,Ma, Hong,Zhang, Dong-Jie,Guo, Zhen-Hua,Guo, Yun-Yun,Zhu, Meng,Bai, Jing Asian Australasian Association of Animal Productio 2015 Animal Bioscience Vol.28 No.12

The in vitro maturation (IVM) efficiency of porcine embryos is still low because of poor oocyte quality. Although brilliant cresyl blue positive (BCB+) oocytes with low glucose-6-phosphate dehydrogenase (G6PDH) activity have shown superior quality than BCB negative (-) oocytes with high G6PDH activity, the use of a BCB staining test before IVM is still controversial. This study aimed to shed more light on the subcellular characteristics of porcine oocytes after selection using BCB staining. We assessed germinal vesicle chromatin configuration, cortical granule (CG) migration, mitochondrial distribution, the levels of acetylated lysine 9 of histone H3 (AcH3K9) and nuclear apoptosis features to investigate the correlation between G6PDH activity and these developmentally related features. A pattern of chromatin surrounding the nucleoli was seen in 53.0% of BCB+ oocytes and 77.6% of BCB+ oocytes showed peripherally distributed CGs. After IVM, 48.7% of BCB+ oocytes had a diffused mitochondrial distribution pattern. However, there were no significant differences in the levels of AcH3K9 in the nuclei of blastocysts derived from BCB+ and BCB- oocytes; at the same time, we observed a similar incidence of apoptosis in the BCB+ and control groups. Although this study indicated that G6PDH activity in porcine oocytes was correlated with several subcellular characteristics such as germinal vesicle chromatin configuration, CG migration and mitochondrial distribution, other features such as AcH3K9 level and nuclear apoptotic features were not associated with G6PDH activity and did not validate the BCB staining test. In using this test for selecting porcine oocytes, subcellular characteristics such as the AcH3K9 level and apoptotic nuclear features should also be considered. Adding histone deacetylase inhibitors or apoptosis inhibitors into the culture medium used might improve the efficiency of IVM of BCB+ oocytes.

An Engineering Algorithm on Life Damage of a Spider in a Hydraulic Generator Unit Based on Vibration Signal

Fu Zhou Feng,Bo-Suk Yang,Fu Lei Chu 한국소음진동공학회 2003 한국소음진동공학회 국제학술대회논문집 Vol.2003 No.8

Modeling of Piezoelectric Langevin Transducers by Using Mixed Transfer Matrix Methods

Bo Fu,Chao Li,Jianming Zhang,Zhenwei Huang,Tobias Hemsel 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.41

In the modeling of piezoelectric Langevin transducers using the usual transfer matrix methods, some simplifications have been adopted. This leads to a reduction in the model quality. A mixed transfer matrix method is employed in the modeling of Langevin transducers, where the pre-stressed bolt is modeled as a separate four-pole element connected to other elements in parallel. Based on the mixed transfer matrix method, the four (six)-pole element description of the piezoelectric Langevin transducer is built up, and the total transfer matrix relation is derived. The resonance frequencies of the transducer are calculated and then measured using an impedance analyzer (HP4192). Experimental results show that the mixed transfer matrix method has better modeling quality than the usual transfer matrix method for the vibration analysis of piezoelectric Langevin transducers.

First Principles Study of Structural and Electronic Properties of Pentagonal and Hexagonal Noble Metal Nanowires

Zhijian Fu,Li-Jun Jia,JIHONG XIA,Hai-Bo Ruan,Ke Tang,Yong Pu,Zhao-Yi Zeng,Dian-Yong Tang,Bo Kong,Qi-Feng Chen 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.6

The equilibrium structure and electronic properties of four ultrathin free-standing pentagonal and hexagonal noble metal nanowires, that is, copper nanowires (CuNWs), silver nanowires (AgNWs), gold nanowires (AuNWs) and platinum nanowires (PtNWs), have been studied comprehensively by adopting a first-principles simulation based on the density-functional theory. The staggered topologies are more stable than the eclipsed ones by analyzing the bonding energy. The staggered ones with a linear atom chain in the center of the pentagonal or hexagons topologies are the preferred structures for CuNWs and AgNWs, but the staggered ones without a linear atom chain in the center of the pentagon or hexagon are the preferred structures for AuNWs and PtNWs due to the increasing core–core repulsions. The calculated electronic band structures and density of states present that all the noble metal nanowires are metallic. The projected densities of states (PDOS) of dominant d-states and the charge density show that the narrower d-state moved to the Fermi energy and metallic bonding character for all the noble metal nanowires.

Enhancement of Virus-induced Gene Silencing in Tomato by Low Temperature and Low Humidity

Da-Qi Fu,Ben-Zhong Zhu,Hong-Liang Zhu,Hong-Xing Zhang,Yuan-Hong Xie,Wei-Bo Jiang,Xiao-Dan Zhao,Yun-Bo Luo 한국분자세포생물학회 2006 Molecules and cells Vol.21 No.1

Virus-induced gene silencing (VIGS) is an attractive reverse-genetics tool for studying gene function in plants. We showed that silencing of a phytoene desaturase (PDS) gene is maintained throughout TRV-PDSinoculated tomato plants as well as in their flowers and fruit and is enhanced by low temperature (15°C) and low humidity (30%). RT-PCR analysis of the PDS gene revealed a dramatic reduction in the level of PDS mRNA in leaves, flowers and fruits. Silencing of PDS results in the accumulation of phytoene, the desaturase substrate. In addition, the content of chlorophyll a, chlorophyll b and total chlorophyll in the leaves of PDS-silenced plants was reduced by more than 90%. We also silenced the LeEIN2 gene by infecting seedlings, and this suppressed fruit ripenning. We conclude that this VIGS approach should facilitate large-scale functional analysis of genes involved in the development and ripening of tomato.

Effect of structural phase transformations under pressure on electronic and optical properties of CuInS2

Bo Gao,Hong-Tao Xue,Fu-Ling Tang,Yu-Wen Cheng 한국물리학회 2017 Current Applied Physics Vol.17 No.11

First-principles plane-wave calculations were employed to study the phase transitions, electronic and optical properties of chalcopyrite CuInS2 (CIS) under pressure, which is a promising semiconductor compound material for nonlinear optical, photovoltaic and bio-applications. From the variations of Gibbs free energy and volume with pressure, we confirmed an experimentally found phase transformation of CIS from tetragonal I42d structure into the cubic Fm3m phase. It occurs at 7.9 GPa with a volume reduction of 15.6%, which are comparable with the experimental values of 9.5 GPa and 12%. A new possible phase transition of CIS from the cubic Fm3m structure to the orthorhombic Cmcm structure under higher pressure was predicted occurring at 49.6 GPa with a volume reduction about 0.64%. Using the more accurate HSE06 functional, we found that the growth rate of energy gap with pressure (dEg/dP) for the I42d phase is about 24.8 meV/GPa, very close to the experimental value of 24 meV/GPa. The calculated electronic properties for Fm3m and Cmcm phases show that CIS is a metallic material under high pressure, rather than a semiconductor. The optical absorption spectra indicate that with the increase of pressure the absorption edge of CIS becomes smaller while the optical energy gap is larger.

Populist Terrorist Activities and their Impact in Pakistan

Bo Tu,Bingfeng Fu,Yunsong Zhou,Daitong Liang 한국정치사회연구소 2020 한국과 국제사회 Vol.4 No.1

In Pakistan, there are various types of populist organizations, among which some extreme populist organizations such as those in Baluchistan, Sindh, Gilgit and other regions have become extreme and taken on a certain terrorist nature because of Pakistan s history and politics as well as the long tradition of Pakistan s domestic terrorism. These extremist populist organizations have not only posed a threat to Pakistan s national security and development, but also hindered the strengthening of both China-Pakistan bilateral relations and the cooperation around the Belt and Road Initiative. The specific organizational structure of these extreme populist groups and the impact of their terrorist activities on both Pakistan and the rest of the world deserve attention in the academic community. By adopting a literature review approach, in this paper, Pakistan’s domestic populist organizations are sorted reasonably, the structure of extreme populist organizations is clarified accordingly, and the influence of their terrorist activities is noted emphatically. The conclusion drawn is that Pakistan’s domestic extreme populist groups have not only severely constrained Pakistan’s economic development and lowered the people’s living standards, but also hindered the strengthening of Pakistan’s diplomatic relations with neighboring countries, thus worsening Pakistan’s domestic political environment and impeding its integration into the trend of globalization. 파키스탄의 포퓰리즘 조직은 몇 가지 유형으로 나눌 수 있다, 그 중에 극단적 포퓰리즘 조직의 예를 들면 발루치스탄(Baluchistan), 신드(Sindh), 길기트(Gilgit) 등 지역의 포퓰리즘조직은 역사적, 정치적 원인으로 테러리즘 성질을 가지고 있다. 이러한 극단적 포퓰리즘 조직들은 파키스탄의 국가 안보 및 발전에 영향을 줄 뿐만 아니라 중-파 양국관계 및 “일대일로”를 중심으로 한 협력에도 영향을 준다. 이 조직들이 어떻게 형성되었는지, 어떤 특징을 갖고 있는지를 연구하고 구체적으로 파키스탄 및 국제사회에 어떠한 영향을 미치는가가 학계의 관심사이다. 본 논문은 문헌연구를 통해 파키스탄의 포퓰리즘조직을 분류하고, 조직구성 및 그들의 테러리즘활동이 미치는 영향을 연구하였다. 극단적 포퓰리즘조직들은 파키스탄의 국내정치환경을 악화시키고 본국의 국제화를 지연시킨다. 이와 더불어 파키스탄의 경제성장발전과 국민생활 수준의 향상을 저해시키고 있다. 또한 주변국가간의 외교관계도 악화시키고 있다는 점도 도출하였다.

Development of signal analysis method for the motional Stark effect diagnostic on EAST

FU, Jia,LYU, Bo,LIU, Haiqing,LI, Yingying,LIU, Dongmei,WEI, Yongqing,FAN, Chao,SHI, Yuejiang,WU, Zhenwei,WAN, Baonian IOP Publishing 2017 Plasma science & technology Vol.19 No.10

<P>A pilot single-channel Motional Stark Effect (MSE) diagnostic has been developed on EAST since 2015. The dual photo-elastic modulators (PEM) were employed to encode the polarization angle into a time-varying signal. The pitch angle was related to the ratio of modulation amplitude at the second harmonic frequency. A digital harmonic analyzer (DHA) technique was developed for extracting the second harmonic amplitude. The results were validated with a hardware phase lock-in amplifier, and is also consistent with the software dual phase-locking algorithm.</P>

Dynamics of Mixed Lump-Soliton Solutions According to a (2+1)-Dimensional Coupled Nonlinear Partial Differential Like Equation

Bo Ren,Zhi-Wei He,Yong-li Sun,Fu-Dong Wang 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.74 No.8

Based on the generalized bilinear operators in a prime number $p=3$, we introduce a (2+1)-dimensional coupled nonlinear partial differential like equation. By combining an exponential function with a quadratic function, an interaction between a lump wave and a one-kink soliton is generated. In addition, an interaction between a lump wave and a two-kink soliton, which is called a special rogue wave, can be obtained by adding two additional exponential functions. The dynamic properties of these interactions are depicted by selecting appropriate parameters.