Chemical composition and in vitro digestibility of corn stover during field exposure and the fermentation characteristics of silage prepared with microbial additives

Jun Lei Gao,Peng Wang,Chang-Hai Zhou,Ping Li,Hong Yu Tang,Jiabao Zhang,Yimin Cai 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.12

Objective: To effectively use corn stover resources as animal feed, we explored the chemical composition and in vitro digestibility of corn stover during field exposure and the fermentation characteristics of silage prepared with lactic acid bacteria (LAB) and cellulase. Methods: Corn ears including the cobs and shucks were harvested at the ripe stage. The corn stover was exposed in the field under natural weather conditions. Silages were prepared after 0, 2, 4, 7, 15, 30, and 60 d of exposure. Corn stover was chopped into approximately 1 to 2 cm lengths and then packed into 5 liter plastic silos. The ensiling density was 550.1±20.0 g/L of fresh matter, and the silos were kept at room temperature (10°C to 25°C). Silage treatments were designed as follows: without additives (control), with LAB, with cellulase, and with LAB+ cellulase. After 45 d of fermentation, the silos were opened for chemical composition, fermentation quality and in vitro digestion analyses. Results: After harvest, corn stover contained 78.19% moisture, 9.01% crude protein (CP) and 64.54% neutral detergent fiber (NDF) on a dry matter (DM) basis. During field exposure, the DM, NDF, and acid detergent fiber (ADF) contents of corn stover increased, whereas the CP and water-soluble carbohydrate contents and in vitro digestibility of the DM and CP decreased (p<0.05). Compared to the control silage, cellulase-treated silage had lower (p<0.05) NDF and ADF contents. The pH values were lower in silage treated with LAB, cellulase, or LAB+cellulase, and lactic acid contents were higher (p<0.05) than those of the control. Silage treated with cellulase or LAB+cellulase improved (p<0.05) the in vitro DM digestibility (IVDMD) compared to that of the control or LAB-treated silage. Conclusion: Corn stover silage should be prepared using fresh materials since stover nutrients are lost during field exposure, and LAB and cellulase can improve silage fermentation and IVDMD.

Investigation on Oil-paper Degradation Subjected to Partial Discharge Using Chaos Theory

Jun Gao,Youyuan Wang,Ruijin Liao,Ke Wang,Lei Yuan,Yiyi Zhang 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.5

In this paper, oil-paper samples composed of transformer windings were used to investigate the insulation degradation process subjected to partial discharge (PD), with artificial defects inside to simulate the PD induced insulation degradation. To determine appropriate test voltages, the breakdown time obtained through a group of accelerated electrical degradation tests under high voltages was firstly fitted by two-parameter Weibull model to acquire the average breakdown time, which was then applied to establish the inverse power law life model to choose advisable test voltages. During the electrical degradation process, PD signals were synchronously detected by an ultra-high frequency (UHF) sensor from inception to breakdown. For PD analysis, the whole degradation process was divided into ten stages, and chaos theory was introduced to analyze the variation of three chaotic parameters with the development of electrical degradation, namely the largest Lyapunov exponent, correlation dimension and Komogorov entropy of PD amplitude time series. It is shown that deterministic chaos of PD is confirmed during the oil-paper degradation process, and the obtained results provide a new effective tool for the diagnosis of degradation of oil-paper insulation subjected to PD.

Investigation on Oil-paper Degradation Subjected to Partial Discharge Using Chaos Theory

Gao, Jun,Wang, Youyuan,Liao, Ruijin,Wang, Ke,Yuan, Lei,Zhang, Yiyi The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.5

In this paper, oil-paper samples composed of transformer windings were used to investigate the insulation degradation process subjected to partial discharge (PD), with artificial defects inside to simulate the PD induced insulation degradation. To determine appropriate test voltages, the breakdown time obtained through a group of accelerated electrical degradation tests under high voltages was firstly fitted by two-parameter Weibull model to acquire the average breakdown time, which was then applied to establish the inverse power law life model to choose advisable test voltages. During the electrical degradation process, PD signals were synchronously detected by an ultra-high frequency (UHF) sensor from inception to breakdown. For PD analysis, the whole degradation process was divided into ten stages, and chaos theory was introduced to analyze the variation of three chaotic parameters with the development of electrical degradation, namely the largest Lyapunov exponent, correlation dimension and Komogorov entropy of PD amplitude time series. It is shown that deterministic chaos of PD is confirmed during the oil-paper degradation process, and the obtained results provide a new effective tool for the diagnosis of degradation of oil-paper insulation subjected to PD.

Constrained k Nearest Neighbor Query for Uncertain Object in the Network

Gao Jun 보안공학연구지원센터 2014 International Journal of Hybrid Information Techno Vol.7 No.5

Design and Experiments of a Linear Motor with High-speed and High-thrust Force for the replacement of hydraulic actuator

Jun Gao(고준),J.H. Choi(최종현),Y.S. Kueon(권영섭),Y.S. Baek(백윤수) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11

Hydraulic actuators are normally used in the systems requiring a large amount of motive force. However, when the system requires high frequency and fast response, it is hard to control the actuator which is shown to have low mechanical performance. Therefore direct-driven electromagnetic linear actuator system is demanded. This paper deals with a linear motor system which is replaced to achieve direct linear motion. The modeling has been done with Finite Element(FE) Analysis and two prototypes have been designed and fabricated. They are designed with moving-coil and moving-magnet type. Halbach array is used on the second type to reduce detent force. In this study, FE analytical results are validated by experiments. The results show that thrust force is about 6,000N and detent force is reduced to approximately 35N. The linear motor system presented in the work can be used for other devices, just like machine-tool sliding tables, continuous casters and so on.

Credible Nearest Neighbor Query in Uncertain Network

Gao Jun 보안공학연구지원센터(IJGDC) 2014 International Journal of Grid and Distributed Comp Vol.7 No.1

Study on the Mechanical Properties and Microstructure of Geogrid Under Different Materials and Temperatures

Junli Gao,Haibing Zhang,Xuelei Xie,Yapo Zhang 한국섬유공학회 2022 Fibers and polymers Vol.23 No.6

In response to the environmental problems caused by the difficulty of direct degradation of the raw materials usedin traditional geogrids and the impact of different temperatures on the mechanical properties of geogrids in practicalengineering applications, based on 3D printing technology, polylactic acid (PLA), carbon fiber reinforced polylactic acid(PLA/CF), and thermoplastic polyurethane (TPU) geogrids were fabricated. The 3D printed geogrids and the fiberglassgeogrids used in the actual project were tested in indoor tensile tests under different temperature conditions. The mechanicalproperties of the geogrids of the four kinds of materials and six kinds of temperature were analyzed. The microstructure of thegeogrids after tensile tests was investigated based on scanning electron microscopy technology to further analyze the effectsof different materials and temperatures on the mechanical properties of the geogrids. The results showed that the tensilestrength of PLA/CF geogrids and PLA geogrids decreased with increasing temperature. The tensile strength of fiberglassgeogrids increased with rising temperatures. The tensile strength of PLA/CF geogrids was significantly better than PLAgeogrids. Due to the addition of carbon fiber in PLA, PLA/CF can bear more tensile force at high temperatures. With theincrease of temperature, the elongation at break of PLA/CF geogrids and fiberglass geogrids increased, but the elongation atbreak of PLA geogrids decreased. The elongation at break of PLA/CF geogrids was significantly lower than that of PLAgeogrids. TPU geogrids had high tensile capacity in a high-temperature environment, and they also had high elasticity andmore significant elongation at break, which was not suitable to be used as geogrid material.

Molecular and Biochemical Characterization of a Novel Intracellular Low-Temperature-Active Xylanase

( Jun Pei Zhou,),( Yan Yan Dong ),( Xiang Hua Tang ),( Jun Jun Li ),( Bo Xu ),( Qian Wu ),( Ya Jie Gao ),( Lu Pan ),( Zun Xi Huang ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.4

A 990 bp full-length gene (xynAHJ2) encoding a 329- residue polypeptide (XynAHJ2) with a calculated mass of 38.4 kDa was cloned from Bacillus sp. HJ2 harbored in a saline soil. XynAHJ2 showed no signal peptide, distinct amino acid stretches of glycoside hydrolase (GH) family 10 intracellular endoxylanases, and the highest amino acid sequence identity of 65.3% with the identified GH 10 intracellular mesophilic endoxylanase iM-KRICT PX1-Ps from Paenibacillus sp. HPL-001 (ACJ06666). The recombinant enzyme (rXynAHJ2) was expressed in Escherichia coli and displayed the typical characteristics of low-temperatureactive enzyme (exhibiting optimum activity at 35 o C, 62% at 20 o C, and 38% at 10 o C; thermolability at ≥45 o C). Compared with the reported GH 10 low-temperature-active endoxylanases, which are all extracellular, rXynAHJ2 showed low amino acid sequence identities (<45%), low homology (different phylogenetic cluster), and difference of structure (decreased amount of total accessible surface area and exposed nonpolar accessible surface area). Compared with the reported GH 10 intracellular endoxylanases, which are all mesophilic and thermophilic, rXynAHJ2 has decreased numbers of arginine residues and salt bridges, and showed resistance to Ni 2+ , Ca 2+ , or EDTA at 10 mM final concentration. The above mechanism of structural adaptation for low-temperature activity of intracellular endoxylanase rXynAHJ2 is different from that of GH 10 extracellular low-temperature-active endoxylanases. This is the first report of the molecular and biochemical characterizations of a novel intracellular low-temperatureactive xylanase.

Environmental fatigue correction factor model for domestic nuclear-grade low-alloy steel

Gao, Jun,Liu, Chang,Tan, Jibo,Zhang, Ziyu,Wu, Xinqiang,Han, En-Hou,Shen, Rui,Wang, Bingxi,Ke, Wei Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.8

Low cycle fatigue behaviors of SA508-3 low-alloy steel were investigated in room-temperature air, high-temperature air and in light water reactor (LWR) water environments. The fatigue mean curve and design curve for the low-alloy steel are developed based on the fatigue data in room-temperature and high-temperature air. The environmental fatigue model for low-alloy steel is developed by the environmental fatigue correction factor (F_en) methodology based on the fatigue data in LWR water environments with the consideration of effects of strain rate, temperature, and dissolved oxygen concentration on the fatigue life.

The Statistical Methods of Membership Function in Structural Serviceability Failure Criterion

Jun Gao,Jitao Yao,Liuzhuo Chen 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.11

The failure criterion of structural serviceability is often fuzzy, which has a direct impact on the results of structural reliability analysis. Membership function is a basic mathematical tool to describe the fuzziness of failure criteria. At present, the fuzzy statistical method for generating the fuzzy set membership function is to take the numerical interval of the fuzzy set as a sample, and directly generate the membership function through statistics. However, this kind of sample will cover the uncertainty of the individual's understanding of fuzzy boundaries to a certain extent, and its statistical results are difficult to truly reflect the characteristics of fuzzy sets. The fuzzy boundary is described by the membership density function, and the numerical interval covering the fuzzy boundary is taken as the sample. The fuzzy statistical method for generating the membership density function is proposed, and the indirect statistical method for generating the membership function is established. The comparative analysis results show that the membership functions generated by the two statistical methods are different. The membership function generated by indirect statistical method can fully reflect the uncertainty of the individual's understanding of the fuzzy boundary, more truly reflect the characteristics of the fuzzy set, and provide a more solid foundation for the fuzzy probability analysis of structural serviceability.