Re-entrant relaxor ferroelectricity of methylammonium lead iodide

Haiyan Guo,Peixue Liu,Shichao Zheng,Shixian Zeng,Na Liu,Seungbum Hong 한국물리학회 2016 Current Applied Physics Vol.16 No.12

We have performed a piezoresponse force microscopy (PFM) study on methylammonium lead iodide (MAPbI3) thin films in normal (non-resonance, non-band-excitation) contact mode. In contrast to the ferroelectric Pb0.76Ca0.24TiO3 (PCT) control sample, a typical ferroelectric response was not observed. However, a nonlinear electric field dependence of the local PFM amplitude was found in MAPbI3, similar to PCT. An analysis combining results on structure, dielectric dispersion, and weak ferroelectricity demonstrates that MAPbI3 is actually a re-entrant relaxor ferroelectric which, upon cooling, enters into a relaxor phase below its ferroelectric phase transition at ~327 K, due to the balance between the long range ferroelectric order and structural methylammonium group orientational disorder. The ferroelectricity at room temperature is compromised due to the re-entrant relaxor behavior, causing the poor polarization retention or weak ferroelectricity. Our findings essentially conciliate the conflicting experimental results on MAPbI3's ferroelectricity and are beneficial both for basic understanding as well as for device applications.

Comparative Transcriptome Analysis of Rhizoctonia solani-resistant and -Susceptible Rice Cultivars Reveals the Importance of Pathogen Recognition and Active Immune Responses in Host Resistance

Guo-Liang Wang,Shaohong Qu,Zhengjie Yuan,Yu Zhang,Guojuan Xu,Dongling Bi,Haiyan Qu,Xiaowei Zou,Xiaoqing Gao,Haihe Yang,Haiyan He,Xuli Wang,Jiandong Bao,Shimin Zuo,Xuebiao Pan,Bo Zhou 한국식물학회 2018 Journal of Plant Biology Vol.61 No.3

Rice sheath blight (SB), caused by Rhizoctoniasolani (R. solani), is a major threat to rice productionworldwide. The molecular mechanisms of the SB resistancein rice are poorly understood. The transcriptomes of the SBresistantrice cultivar YSBR1 and the susceptible cultivarLemont were analyzed after R. solani infection. A total of7624 differentially expressed genes (DEGs) were identifiedat one or more timepoints in a cultivar. 5526 and 5618 DEGswere differentially expressed in Lemont and YSBR1,respectively. YSBR1 exhibited stronger and earlier transcriptionalresponse to R. solani than Lemont. Gene ontology enrichmentanalysis revealed that genes that encode cell wall-modifyingand glycosyl-degrading enzymes or anti-microbial proteinswere specifically induced in YSBR1 at 6 hpi. MapMananalysis revealed that more DEGs related with cell wall, β-glucanses, respiratory burst, phenylpropanoids and ligninwere highly induced by R. solani in YSBR1 than in Lemont. The results also showed that receptor-like kinases and jasmonicacid signaling may play important roles in host resistance toR. solani. This study highlights potential candidate genes andsignaling pathways involved in rice sheath resistance and canhelp to further clarify the mechanistic events underlyingresistance and susceptibility to R. solani.

Two-Step Oxidation of Refractory Gold Concentrates with Different Microbial Communities^s

( Guo-hua Wang ),( Jian-ping Xie ),( Shou-peng Li ),( Yu-jie Guo ),( Ying Pan ),( Haiyan Wu ),( Xin-xing Liu ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.11

Bio-oxidation is an effective technology for treatment of refractory gold concentrates. However, the unsatisfactory oxidation rate and long residence time, which cause a lower cyanide leaching rate and gold recovery, are key factors that restrict the application of traditional bio-oxidation technology. In this study, the oxidation rate of refractory gold concentrates and the adaption of microorganisms were analyzed to evaluate a newly developed two-step pretreatment process, which includes a high temperature chemical oxidation step and a subsequent bio-oxidation step. The oxidation rate and recovery rate of gold were improved significantly after the two-step process. The results showed that the highest oxidation rate of sulfide sulfur could reach to 99.01 % with an extreme thermophile microbial community when the pulp density was 5%. Accordingly, the recovery rate of gold was elevated to 92.51%. Meanwhile, the results revealed that moderate thermophiles performed better than acidophilic mesophiles and extreme thermophiles, whose oxidation rates declined drastically when the pulp density was increased to 10% and 15%. The oxidation rates of sulfide sulfur with moderate thermophiles were 93.94% and 65.73% when the pulp density was increased to 10% and 15%, respectively. All these results indicated that the twostep pretreatment increased the oxidation rate of refractory gold concentrates and is a potential technology to pretreat the refractory sample. Meanwhile, owing to the sensitivity of the microbial community under different pulp density levels, the optimization of microbial community in bio-oxidation is necessary in industry.

Surface plasmon resonance-enhanced solar-driven photocatalytic performance from Ag nanoparticles-decorated Ti3+ self-doped porous black TiO2 pillars

Guo Zhou,Haiyan Meng,Yan Cao,Xuejun Kou,Shuxiang Duan,Leilei Fan,Ming Xiao,Fangzhou Zhou,Zhenzi Li,Zipeng Xing 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.64 No.-

The tiny Ag nanoparticles-uniformly decorated Ti3+ self-doped porous black TiO2 pillars (Ag-TPBTPs) are prepared, which show obvious surface plasmon resonance (SPR) and extend the photoresponse to visible light and near-infrared region (∼1500 nm). The Ag-TPBTPs exhibit excellent solar-driven photocatalytic activities by mineralizing of high-toxic 2,4-dichlorophenol (∼99%), which is three times higher than that of the pristine TiO2. The remarkable solar-driven photocatalytic performance can be ascribed to the porous pillars structure offering more surface active sites, the self-doped Ti3+ and SPR effect of Ag nanoparticles improving the utilization of solar light, and enhancing the spatial separation efficiency of photogenerated charge carriers.

Rapid Expression of Bm46 in Bombyx mori Cell Lines, Larvae and Pupae

Wang, Haiyan,Chen, Keping,Guo, Zhongjian,Yao, Qin,Wang, Qiang,Mu, Runhong Korean Society of Sericultural Science 2007 International Journal of Industrial Entomology Vol.15 No.1

In this study, ORF 46 of Bombyx mod nucleopolyhedrovirus(Bm46) fused with EGFP was expressed in Bombyx mod cell lines, larvae and pupae by BmNPV Bacmid system. Bm46 and EGFP were cloned into donor plasmid pFastBacHTb, which was transformed to competent DH10B cells containing helper and BmNPV bacmid by site-specific transposition. Recombinant bacmid was used to transfected BmN-4 cells to produce the recombinant baculovirus vBm-Bm46-EGFP. Recombination virus was injected into silkworm larvae and pupae. The expression of the fusion protein was monitored by examining green fluorescence using a fluorescent microscope. Intense fluorescence in cells and silkworm was observed at 4 days post-infection, indicating the Bm46-EGFP fusion gene was expressed successfully.

Hydraulic fracture initiation pressure of anisotropic shale gas reservoirs

Zhu, Haiyan,Guo, Jianchun,Zhao, Xing,Lu, Qianli,Luo, Bo,Feng, Yong-Cun Techno-Press 2014 Geomechanics & engineering Vol.7 No.4

Shale gas formations exhibit strong mechanical and strength anisotropies. Thus, it is necessary to study the effect of anisotropy on the hydraulic fracture initiation pressure. The calculation model for the in-situ stress of the bedding formation is improved according to the effective stress theory. An analytical model of the stresses around wellbore in shale gas reservoirs, in consideration of stratum dip direction, dip angle, and in-situ stress azimuth, has been built. Besides, this work established a calculation model for the stress around the perforation holes. In combination with the tensile failure criterion, a prediction model for the hydraulic fracture initiation pressure in the shale gas reservoirs is put forward. The error between the prediction result and the measured value for the shale gas reservoir in the southern Sichuan Province is only 3.5%. Specifically, effects of factors including elasticity modulus, Poisson's ratio, in-situ stress ratio, tensile strength, perforation angle (the angle between perforation direction and the maximum principal stress) of anisotropic formations on hydraulic fracture initiation pressure have been investigated. The perforation angle has the largest effect on the fracture initiation pressure, followed by the in-situ stress ratio, ratio of tensile strength to pore pressure, and the anisotropy ratio of elasticity moduli as the last. The effect of the anisotropy ratio of the Poisson's ratio on the fracture initiation pressure can be ignored. This study provides a reference for the hydraulic fracturing design in shale gas wells.

Insect-Proof Nets Affect Paddy Field Microclimate Parameters and Grain Quality of Different Japonica Rice Varieties

Zhi Guo,Hongjiang Liu,Jianchu Zheng,Liugen Chen,Haiyan Yuan 한국작물학회 2015 Journal of crop science and biotechnology Vol.18 No.2

Insect-proof nets (IPN) are widely used to protect crops from invertebrate pests. The effects of IPN on the main microclimate parameters of paddy fields, as well as grain quality, were investigated for three japonica Oryza sativa L. varieties (Nanjing 44, Nanjing 45, and Suxiangjing 3) that are widely grown in China. The environmental temperature of IPN-treated fields increased slightly, whereas the maximum value of photosynthetically active radiation (PAR), daily cumulative PAR, and daily cumulative global radiation all decreased. However, the ratio of PAR to global radiation increased significantly, from 15.08 to 45.48%. Compared to the no insect-proof net (NIPN) treatment, the head rice percentage increased significantly for all three varieties; however, the chalky grain percentage, area and degree, and the amylose content all decreased significantly. The response of gel consistency, protein concentration, and the main parameters of the rapid visco analyzer (RVA) profile of rice starch to IPN treatment differed between varieties. The peak viscosity and breakdown were increased compared to the NIPN treatment, whereas the final viscosity and setback were decreased. However, no significant differences were found between the IPN and NIPN treatments. Furthermore, statistical analysis indicated no interaction between rice planting pattern (RPP) and rice variety (RV) for the rice grain quality parameters. These results suggest that IPN treatment improved rice grain quality for all japonica rice varieties studied, possibly due to the slight increase in environmental temperature and increased ratio of PAR to global radiation in IPN treated paddy fields.

中国香港地区CISG适用问题研究

주령커,Guo, Haiyan,Huang, Na,Shao, Tianqin 부산대학교 중국연구소 2018 Journal of China Studies Vol.21 No.1

United Nations Convention on Contracts for International Sale of Goods (CISG) is considered as a core international trade law that may apply to a contract for international sales of goods by most countries in the world. CISG was legislated by United Nations Commission on International Trade Law in 1980 and China was one of the earliest nations that adopted CISG. Although Constitution of the People’s Republic of China states that Chinese territory covers the Chinese mainland, Hong Kong, Macao and Taiwan, there is still a controversy as to whether CISG could be regarded as of applicable law in the Chinese mainland and other territorial units including Hong Kong. This is due to the different legal systems that each region is currently adopting. In this study, we will focus on the pros and cons of application of CISG to Hong Kong region. Even after Hong Kong’s return to Chinese rule, the central government of China still have not made any declaration regarding the application of CISG to Hong Kong for the reason that Hong Kong was once a British colony and United Kingdom was not of a contracting state of CISG. Until now Hong Kong’s application of CISG is instigating many arguments among states in the world. According to the cases of each country, civil law countries such as France claims that CISG should not be adopted by Hong Kong. In contrast, in the cases in common law countries such as United States of America states that CISG must be applied to Hong Kong. As such, there is no universal consensus with regard to this issue. This study will first summarize the positions of each state toward this issue and then analyze how the Chinese government must conduct for the greatest effect. This study will be conducted based on the assumption that the Chinese government is likely to declare that CISG is applicable to Hong Kong. However, it does not mean that this research will completely exclude the possibility that the Chinese government will continuously keep silence. As a participant in international trade, we are obligated to pronounce our opinions for this issue of the application of CISG to Hong Kong before the Chinese government finally makes a statement to this problem.

Stress field interference of hydraulic fractures in layered formation

Zhu, Haiyan,Zhang, Xudong,Guo, Jianchun,Xu, Yaqin,Chen, Li,Yuan, Shuhang,Wang, Yonghui,Huang, Jingya Techno-Press 2015 Geomechanics & engineering Vol.9 No.5

Single treatment and staged treatments in vertical wells are widely applied in sandstone and mudstone thin interbedded (SMTI) reservoir to stimulate the reservoir. The keys and difficulties of stimulating this category of formations are to avoid hydraulic fracture propagating through the interface between shale and sand as well as control the fracture height. In this paper, the cohesive zone method was utilized to build the 3-dimensional fracture dynamic propagation model in shale and sand interbedded formation based on the cohesive damage element. Staged treatments and single treatment were simulated by single fracture propagation model and double fractures propagation model respectively. Study on the changes of fracture vicinity stress field during propagation is to compare and analyze the parameters which influence the interfacial induced stresses between two different fracturing methods. As a result, we can prejudge how difficult it is that the fracture propagates along its height direction. The induced stress increases as the pumping rate increasing and it changes as a parabolic function of the fluid viscosity. The optimized pump rate is $4.8m^3/min$ and fluid viscosity is $0.1Pa{\cdot}s$ to avoid the over extending of hydraulic fracture in height direction. The simulation outcomes were applied in the field to optimize the treatment parameters and the staged treatments was suggested to get a better production than single treatment.

中国香港地区CISG适用问题研究

Zhou, Lingke,Guo, Haiyan,Huang, Na,Shao, Tianqin 부산대학교 중국연구소 2018 Journal of China Studies Vol.21 No.1