UAVs Cooperative Attack Based on Archimedes Spiral

Zhenming LI,Chaoyong Li,Shuo Zhuo,Sai Chen 제어로봇시스템학회 2017 제어로봇시스템학회 국제학술대회 논문집 Vol.2017 No.10

This paper investigates a control of track based on Archimedes spiral. The objective is to control UAVs (Unmanned Aerial Vehicle) circled to the target under the preset track and in a certain time interval. For the circumstance of the known location of start point and target point of UAV, we put forward a control method of angular velocity, with fixed velocity and trajectory of UAV. And in this control method, based on the nature of the Archimedes spiral, the time of UAV from the start point to the target point can be accurately calculated.

Failure Analyses of a Reinforced Embankment by Strength Reduction and Limit Equilibrium Methods Considering Hardening of Soft Clay

Jianfeng Chen,Junxiu Liu,Jianfeng Xue,Zhenming Shi 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.7

A 7.6 m high reinforced embankment-wall system was constructed in stages on very thick soft clay. The reinforced structure incurred a deep-seated global failure at the end of backfill loading. The Strength Reduction Method (SRM) and the Limit Equilibrium Method (LEM) were employed to analyze the stability of the structure. It was found that the SRM captured the deep-seated global failure of the structure through a coupled mechanical and hydraulic Finite Element (FE) modeling. The stability of the reinforced structure was much underestimated or overestimated by the LEM using unconsolidated-undrained or consolidated-undrained shear strength values. However, the stability of the structure could be still captured by the LEM with the increased shear strength values assigned to the consolidated zone directly beneath the reinforced structure and with the unconsolidated-undrained shear strength values assigned to the unconsolidated zone beyond the structure. In practice, both the SRM and the LEM are recommended for stability analyses of geosynthetic-reinforced structures on soft ground considering hardening of the soil so that the results from the two methods can be cross-examined.

Experimental Measurement and Numerical Computation of Geogrid Tension in Centrifuge Modeling

Jianfeng Chen,Songbo Yu,Jianfeng Xue,Zhenming Shi 대한토목학회 2011 KSCE JOURNAL OF CIVIL ENGINEERING Vol.15 No.8

Tension measurement of geogrid is essential in reinforcement mechanisms studies. Geogrid is a nonlinear flexible material with large apertures, it is difficult to measure the tensions mobilized in geogrid, especially in scaled-down geogrid in centrifuge modeling. In this study, strain gauges were glued onto the surface of model geogrid with epoxy resin and were calibrated through multi-stage and continuous tensile tests. Generalized Kelvin model was used to fit the constitutive curves from the tensile tests. The model is capable to describe time-dependent and nonlinear behavior of the composite material of epoxy resin and model geogrid. Based on generalized Kelvin model, tensions in the model geogrid were measured in a centrifugal modeling of a reinforced embankment on soft clay. A finite element model was developed to simulate the centrifuge modeling and a comparison was carried out between the computed and measured tensions. The numerical results basically captured the measured reinforcements, indicating that the method of reinforcement measurement proposed in this study is appropriate and reasonable.

Finite-element analysis and design of aluminum alloy RHSs and SHSs with through-openings in bending

Ran Feng,Tao Yang,Zhenming Chen,Krishanu Roy,Boshan Chen,James B. P. Lim 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.46 No.3

This paper presents a finite-element analysis (FEA) of aluminum alloy rectangular hollow sections (RHSs) and square hollow sections (SHSs) with circular through-openings under three-point and four-point bending. First, a finite-element model (FEM) was developed and validated against the corresponding test results available in the literature. Next, using the validated FE models, a parametric study comprising 180 FE models was conducted. The cross-section width-to-thickness ratio (b/t) ranged from 2 to 5, the hole size ratio (d/h) ranged from 0.2 to 0.8 and the quantity of holes (n) ranged from 2 to 6, respectively. Third, results obtained from laboratory test and FEA were compared with current design strengths calculated in accordance with the North American Specifications (NAS), the modified direct strength method (DSM) and the modified Continuous strength method (CSM). The comparison shows that the modified CSM are conservative by 15% on average for aluminum alloy RHSs and SHSs with circular through-openings subject to bending. Finally, a new design equation is proposed based on the modified CSM after being validated with results obtained from laboratory test and FEA. The proposed design equation can provide accurate predictions of flexural capacities for aluminum alloy RHSs and SHSs with circular throughopenings.

A Facile Process Combined with Electroless Deposition and Hydrophobic Treatment to Fabricate Self-cleaning Radiation Protection Suits for Pregnant Woman

Wenya Liu,Di Sun,Haodong Ma,Zhenming Chen,Chengmei Gui,Junjun Huang 한국섬유공학회 2022 Fibers and polymers Vol.23 No.5

Silver-printed terylene is presented to fabricate anti-electromagnetic radiation Maternity Dress (AMD) withsuperior shielding effectiveness, but the use of noble metal as electromagnetic interference shielding materials enhances costof raw material and restricts its application. In this study, a facile process combined with electroless deposition andhydrophobic treatment to fabricate self-cleaning radiation protection cotton for AMD was established. The active groups onthe plant fiber surface could absorb Sn2+ and Pd2+ through coordination effect, acting as catalytic center, which can catalyzethe reduction of Ni2+ in the plating solution. Ni particle deposited on the its surface with deposited amount of 32 %. Thefabricated material exhibited an shielding effectiveness of 52.5 dB and it meet AMD criteria. Owing to the cooperation of thelow surface energy and rough structure of precipitation, the Ni-plated cotton modified with (3-Mercaptopropyl)trimethoxysilane exhibited remarkable hydrophobicity with water contact angle up to 112.8 o and excellent self-cleaningproperty.

Effects of Supplementary Chinese Milk Vetch Silage and Rapeseed Meal on the Performance and Rumen Fermentation of Lambs Given Ammoniated Rice Straw Based Diet

Wu, Yueming,Liu, Jian Xin,Chen, Zhenming Asian Australasian Association of Animal Productio 1998 Animal Bioscience Vol.11 No.4

This study was proposed to investigate effects of inclusion of Chinese milk vetch silage (MVS) and rapeseed meal (RSM) on the growth and rumen fermentation of Hu-sheep. Fifty weanling lambs were randomly divided into five equal groups and offered ammoniated rice straw (ABRS) ad libitum along with 100 g concentrate (Trial 1). The animals in $T_0$, $T_1$, $T_2$, $T_3$ and $T_4$ group were respectively supplemented with MVS at levels of 0, 0, 7, 14 or 21% and with RSM at levels of 0, 15, 10, 5 or 0%. Daily gain of lambs was significantly (p<0.05) higher in $T_1$, $T_2$ and $T_3$ group than that in $T_0$ and $T_4$ group. Feed conversion ratio was greatly reduced in supplemented groups as compared with $T_0$ group. In trial 2, five sheep with rumen cannulae were used in a $5{\times}5$ Latin square design. The experimental treatments were as described in Trial 1, but without concentrate. The intake of AVRS was significantly (p<0.05) lower in $T_4$ group than that in $T_0$ group, and also significantly (p<0.05) lower than those in $T_1$ and $T_2$ group. Little difference among all treatments was found in 48h DM degradability of ABRS, MVS and RSM, and in rumen pH value and microbial protein concentration. Rumen concentrations of individual and total VFA tended to be higher in supplemented groups than those in $T_0$ group.These rusults suggest that supplementation with RSM or RSM plus MVS can effectively improve the performance of lambs, and may fail to influence markedly the rumen digestion of ABRS and rumen environments.

A facile technique to prepare cross-linked enzyme aggregates using p-benzoquinone as cross-linking agent

Anming Wang,Fangkai Zhang,Feifei Chen,Meizhang Wang,Haifeng Li,Zhaowu Zeng,Tian Xie,Zhenming Chen 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.4

To obtain robust and thermo-stable enzyme aggregates, p-benzoquinone was used as cross-linker and bovine serum albumin (BSA) as crowding macromolecules to prepare cross-linked enzyme aggregates (CLEAs) of lipase. Effects of cross-linking time and cross-linker content on the activity, thermal stability and characteristics of enzyme aggregates were examined carefully. It was observed that when the content of p_benzoquinone was 5 mM and amount of BSA was 125% of that of lipase (w/w), the specific activity of cross-linked co-aggregates of lipase and BSA was 79.8 U mg^−1, 2.44-fold of that of cross-linked enzyme aggregates of lipase without BSA. Moreover, after heat treatment for 96 h at 50℃ , the CLEAs prepared with this facile routine kept 75.18% of their initial activity, 5.01-fold more than that of the just CLEAs using glutaraldehyde. Furthermore, BSA macromolecules in lipase CLEAs enhanced the catalytic efficiency of free and just lipase CLEAs without BSA by 1.45 and 2.83 times, respectively. The proposed crosslinking technique would rank among the potential strategies for efficiently preparing robust and thermo-stable enzyme aggregates.

A simple method to isolate structurally and chemically intact brain vascular basement membrane for neural regeneration following traumatic brain injury

Ji Wanqing,Wu Zhiru,Wen Jiaming,Tang Hengxin,Chen Zhuopeng,Xue Bo,Tian Zhenming,Ba Yueyang,Zhang Ning,Wen Xuejun,Hou Bo 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

The brain vascular basement membrane (brain-VBM) is an important component of the brain extracellular matrix, and the three-dimensional structure of the cerebrovascular network nested with many cell-adhesive proteins may provide guidance for brain tissue regeneration. However, the potential of ability of brain-VBM to promote neural tissue regeneration has not been examined due to the technical difficulty of isolating intact brain-VBM.The present study developed a simple, effective method to isolate structurally and compositionally intact brain-VBM. Structural and component properties of the brain-VBM were characterized to confirm the technique. Seed cells were cocultured with brain-VBM in vitro to analyze biocompatibility and neurite extension. An experimental rat model of focal traumatic brain injury (TBI) induced by controlled cortical impact were conducted to further test the tissue regeneration ability of brain-VBM.Brain-VBM isolated using genipin showed significantly improved mechanical properties, was easy to handle, supported high cell viability, exhibited strong cell adhesive properties, and promoted neurite extension and outgrowth. Further testing of the isolated brain-VBM transplanted at lesion sites in an experimental rat model of focal TBI demonstrated considerable promise for reconstructing a complete blood vessel network that filled in the lesion cavity and promoting repopulation of neural progenitor cells and neurons.The technique allows isolation of intact brain-VBM as a 3D microvascular scaffold to support brain tissue regeneration following TBI and shows considerable promise for the production of naturally-derived biomaterials for neural tissue engineering.

Thermal Analysis Study of Modified Urea-Formaldehyde Resin

Wei Hong,Mianwu Meng,Dingding Gao,Qingye Liu,Caiyan Kang,Siyu Huang,Zhenming Zhou,Chunqiang Chen 한국고분자학회 2016 폴리머 Vol.40 No.5

In this study, the structures and thermal stability of pure urea-formaldehyde resin (PR) and modified urea-formaldehyde (UF) resin are investigated by differential thermal gravity (TG/DTG), and differential scanning calorimetry (DSC) supported by data from Fourier transform infrared spectroscopy. FTIR analysis indicate that the modifiers such as polydimethylsiloxane, dicyclohexylcarbodiimide and phenol have actively participated in the curing reactions. TG/DTG and DSC curve of UF resin show that its pyrolysis process is conducted in three steps: desiccation and dehydration, flash pyrolysis and slow decomposition. Compared with pure urea-formaldehyde resin (PR), modified UF resin exhibited good thermal stability. The activation energy (E) of modified UF resin acquired by Kissinger and Ozawa method was higher than that of PR. ΔH > 0, ΔS > 0 and ΔG > 0 in the thermal decomposition process of UF resin means that the decomposition reaction of UF resin before and after modification is a process of unnatural decalescence and entropy increase.

High-Conductivity SiO2-Matrix B-Doped Si-NC Thin Films by Following Ion-Beam Treatment

Junjun Huang,Weiyan Wang,Jie Yang,Yongzhen Tan,Wei Chen,Tianyu Ge,Yajun Zhang,Min Gao,Zhenming Chen 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.6

In this work, further ion-beam was performed on SiO2-matrix B-doped Si-NC (SBC) thin films in order to enhance conductivity. The effect of ionbeamtype on the electrical properties of SBC thin films was investigatedsystematically. The results indicated that the conductivities of SBC thinfilms were significantly improved by both argon and hydrogen ion-beamtreatments, and the higher the hydrogen ion ratio, the higher theconductivity of SBC thin films. The conductivity of SBC thin films wasincreased from 1.82 × 10−6 S/cm to 3.2 × 10−3 S/cm with followinghydrogen-ion-beam treatment. The change in conductivity of SBC thinfilms was most possibly resultant from the ion-beam treatment facilitatingthe formation of higher superficial order and lower defects. An alternativemethod was proposed to prepare high-conductivity SBC thin films, whichmay be applied to other heterogeneous thin films.