Regulation of precursor solution concentration for In-Zn oxide thin film transistors

Zhongyuan He,Yanping Chen,Yaogang Li,Qinghong Zhang,Chengyi Hou,Hongzhi Wang 한국물리학회 2018 Current Applied Physics Vol.18 No.11

The tunable electronic performance of the solution-processed semiconductor metal oxide is of great significance for the printing electronics. In current work, transparent thin-film transistors (TFTs) with indium-zinc oxide (IZO) were fabricated as active layer by a simple eco-friendly aqueous route. The aqueous precursor solution is composed of water without any other organic additives and the IZO films are amorphous revealed by the X-ray diffraction (XRD). With systematic studies of atomic force microscopy (AFM), X-ray photoemission spectroscopy (XPS) and the semiconductor property characterizations, it was revealed that the electrical performance of the IZO TFTs is dependent on the concentration of precursor solution. As well, the optimum preparation process was obtained. The concentrations induced the regulation of the electronic performance was clearly demonstrated with a proposed mechanism. The results are expected to be beneficial for development of solution-processed metal oxide TFTs.

The Grain-Based Model Numerical Simulation of Unconfined Compressive Strength Experiment Under Thermal-Mechanical Coupling Effect

Zhongyuan Xu,Tianbin Li,Guoqing Chen,Chunchi Ma,Shili Qiu,Zhi Li 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.8

PFC-GBM (Particle Flow Code-Grain Based Model) is the major and fundamental method to simulate rock behaviors in thispaper. Geo-materials are composed of micro-grains, the behavior of these grains and the interface between them influencemacroscopic behavior of materials. Traditional PFC simulation method could simulate the integral micro-behavior of material, andPFC-GBM simulation focuses on every different grains and interfaces to simulate micro-heterogeneity of material. In this paper, anattempt is made to investigate the strength of rock masses and the development of micro-cracks under thermal-mechanical couplingeffect. For this purpose, a numerical model is established based on mineral analysis and pre-existing mechanical experiments ofGranite from one of complex tunnels in Yunnan Province. After establishing the model, the specimen were first heated and thencompressed according to test sequence of laboratory experiments. The simulation results are calibrated to match the laboratory testresults including thermal behaviors and fracture development. The conclusion of simulations show that both of thermal behaviorsand fracture development are depended on the micro-heterogeneity of granite in UCS (Unconfined Compressive Strength)experiment, the characteristics of minerals influence the macroscopic fracture mechanism. The simulation reveals that in a certainrange of temperature (40oC ~ 90oC), temperature increasing enhance the brittle damage of granite. The situation of 130oC had theobvious thermal-crack before loading and then exhibited a much lower peak strength and failure strain. This numerical observationmay guide the underground construction in complex geo-environment.

Spontaneous transposition of HzSINE1 into CYP321A2 is undetectable in the field populations of Helicoverpa zea

Li Shengyun,Chen Song,Dong Shuanglin,Zhang Min,Deng Zhongyuan,Ni Xinzhi,Huang Jinyong,Li Xianchun 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.3

The enrichment of transposable elements (TEs) within allelochemical- and insecticide-metabolizing P450 alleles in Helicoverpa zea enables these P450s to gain TE-introduced adaptive variations otherwise not readily available to cope with the ever-changing and diverse xenobiotic stress factors in varying cropping systems. The critical role of each TE-inserted P450 allele depends on whether the inserted P450 allele is more adaptive than its TE-free counterpart or not. Previous study has reported a HzSINE1-inserted CYP321A2 allele in a laboratory strain of H. zea reared with xenobiotic-free artificial diets. Here we show that the HzSINE1-inserted CYP321A2 allele transcribes into two HzSINE1 sequence-containing mutant mRNA isoforms of different length that encode an identical C terminus-truncated and heme-binding region deleted non-functional P450. Nonetheless, HzSINE1 insertion does not disrupt the regulatory functional aspect of CYP321A2 since this allele is constitutively expressed and highly inducible by the allelochemicals xanthotoxin, quercetin and chlorogenic acid. Furthermore, while the HzSINE1-inserted CYP321A2 allele is fixed in the laboratory strain, the insertion is purged in the bifenthrin-resistant strain and the Georgia field population of H. zea. To sum up, the HzSINE1-inserted CYP321A2 allele represents an allelochemical-inducible non-functional P450 allele that is selected against in the field populations frequently encountering toxic plant allelochemicals and synthetic insecticides. However, such an insertion can reach fixation under the xenobiotic-free laboratory rearing conditions most likely due to random genetic drift across multiple generations.

Palynological study on vegetation and climatic change in the subaqueous Changjiang (Yangtze River) delta, China, during the past about 1600 years

Sangheon Yi,Yoshiki Saito,Zhongyuan Chen,Dong Yoon Yang 한국지질과학협의회 2006 Geosciences Journal Vol.10 No.1

The wel-defined pollen record in massive marineclay deposits from the subaqueous Changjiang (Yangtze River)delta reveals changes in vegetation and inferred climate during thelast about 1600 years. Climatic periods inferred from the pollentively warm/wet conditions comparable to Medieval Warm Period(AD 9101085) with a strengthen summer monsoon, (3) a relativelycool and wet conditions possibly corresponding to Little Ice Age(LIA; AD 10851815) with a weaken summer monsoon, and finally(4) the present warm period, since AD 1815. The pollen aridityindex based on variations in humidity suggests that thre subpe-riods within the LIA can be identified: wet LIA-1 (AD 10851170),dry LIA-2 (AD 11701330), and wet LIA-3 (AD 13301815).

Gliding Trajectory Programming of Guided Projectile Based on Improved L1 Penalty Successive Convex Programming Algorithm

Qinghai Wang,Qi Chen,Zhongyuan Wang 제어로봇시스템학회 2021 제어로봇시스템학회 국제학술대회 논문집 Vol.2021 No.10

Taking the general control energy optimal trajectory programming model as the research object, the Radau pseudo-spectral method is used to discretize the continuous variables and then linearly convexify the nonlinear dynamic equation to establish the standard convex optimization model. In order to solve the problems of large amount of redundant computation and slow convergence speed of the traditional L1 penalty successive convex programming algorithm (LPSCP), an improved L1 penalty successive convex programming algorithm (ILPSCP) is proposed in this paper. The algorithm introduces the feasibility judgment process to avoid solving the more complex L1 subproblem PL1 when the original problem P0 is feasible. Taking the gliding trajectory model of the guided projectile in the longitudinal plane as an example, the traditional LPSCP algorithm, the ILPSCP algorithm proposed in this paper and GPOPS2 are used to simulate and compare. The simulation results of ILPSCP algorithm are highly consistent with those of GPOPS2, which proves the effectiveness of the proposed ILPSCP algorithm for solving trajectory programming problems, and the convergence rate of ILPSCP algorithm is improved by 46.36% compared with traditional LPSCP algorithm.

Energy-Optimal Waypoint-Following Guidance for Gliding-Guided Projectiles

Qiulin Yin,Qi Chen,Zhongyuan Wang 제어로봇시스템학회 2021 제어로봇시스템학회 국제학술대회 논문집 Vol.2021 No.10

This paper addresses the problem of energy-optimal way-point-following guidance for Long-Range Gliding-Guided projectiles with the consideration of velocity variation. This proposed guidance law is derived as a solution of a linearized kinematics model. The algorithm integrates path planning and following into a single step and can be applied to a general waypoint-following mission. Nonlinear numerical simulations clearly demonstrate the effectiveness and superiority of the proposed formulations.

Consensus-Based Finite-Time Cooperative Guidance with Field-of-View Constraint

Shuai Ma,Xugang Wang,Zhongyuan Wang,Qi Chen 한국항공우주학회 2022 International Journal of Aeronautical and Space Sc Vol.23 No.5

The problem of cooperative guidance of multiple missiles with field-of-view constraint is addressed based on consensus theory. Considering the singularity problem when the second-order consensus algorithm is directly applied to missile guidance, a novel finite-time consensus algorithm with field-of-view constraint is derived and proved. The singularity problem is also avoided. Cooperative guidance law under 2D and 3D engagement is designed using a two-stage guidance scheme. In the first stage, a decentralized guidance law is designed based on the derived finite-time consensus algorithm to provide the latter stage’s desired initial conditions, and proportional navigation guidance law is used in the second stage. The proposed cooperative guidance law requires neither time-to-go estimation nor controllable velocity magnitude. Compared with other two-stage guidance schemes, the proposed cooperative guidance law can provide better initial conditions for the second stage. Numerical simulation and comparison work demonstrate the effectiveness and superiority of the proposed cooperative guidance law.

An Alkaline pH Control Strategy for Methionine Adenosyltransferase Production in Pichia pastoris Fermentation

Xiaoqing Hu,Ju Chu,Si-Liang Zhang,Ying-ping Zhuang,Xin Wu,Huaxin Chen,Zhongyuan Lv,Zhongyi Yuan 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.5

Pichia pastoris is a successful system forexpressing heterologous proteins and its fermentation pH isalways maintained below 7.0. However, particular proteinsare unstable under acidic conditions, such as methionineadenosyltransferase (MAT), and thus fermentation underacidic pH conditions is unsuitable because protein activityis lost owing to denaturation. Here, a strategy employingalkaline pH in the late fermentation period was developedto improve MAT production. Initially, P. pastoris KM71was transformed with the mat gene to overexpress MAT. After 72 h of in vitro incubation at different pH values, theexpressed MAT displayed highest stability at pH 8.0;however, pH 8.0 inhibited cell growth and induced cellrupture, thus affecting protein production. To balance MATstability and Pichia cell viability, different pH controlstrategies were compared. In strategy A (reference), theinduction pH was maintained at 6.0, whereas in strategy B,it was gradually elevated to 8.0 through a 25 h transitionperiod (80 ~ 105 h). MAT activity was 0.86 U/mg (twofoldhigher than the control). However, MAT content wasreduced by 50% when compared with strategy A, becauseof proteases released upon cell lysis. To improve cellviability under alkaline conditions, glycerol was added inaddition to methanol (strategy C). When compared withstrategy B, the MAT-specific activity remained nearlyconstant, whereas the expression level increased to 1.27 g/L. The alkaline pH control strategy presented herein for MATproduction represents an excellent alternative for expressingproteins that are stable only under alkaline conditions.