INTEGRATED CONTROL OF DIFFERENTIAL BRAKING AND ACTIVE AERODYNAMIC CONTROL FOR IMPROVING HIGH SPEED STABILITY OF VEHICLES

Zhengqiang Chen,Yiwan Wu,Fan Li 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.1

In this paper, an integrated control strategy (ICS) is proposed to improve high speed dynamics stability of the vehicle by the integration of active aerodynamic control (AAC) and differential braking control (DBC). Two aerodynamic surfaces are attached to the roof of the vehicle and servo-controlled separately in real-time. A hierarchical control structure is used to design the proposed scheme, which is composed of an upper and a lower controller. In the upper controller, the additional yaw moment required for stability control is determined by sliding mode control with the consideration of driver inputs, vehicle dynamic and the limitation of road adhesion. In the lower controller, a control strategy is designed to coordinate differential brake and active aerodynamic control, and an optimal control allocation algorithm is adopted to distribute the brake pressure of each wheel. A simplified magic formula tire model is used to describe the nonlinearity of the tires. Two double lane change tests on dry and wet road performed to study the effectiveness of the control algorithm in CarSim/Simulink Co-simulation. The results show the proposed control strategy can effectively improve the vehicle dynamics stability and tire workload usage.

Comestible and temperature effects on the biological traits of fall armyworms, Spodoptera frugiperda

Li Fen,Wang Likui,Lu Rongcai,Peng Zhengqiang,Malhat Farag,Lyu Baoqian,Wu Shaoying 한국곤충학회 2021 Entomological Research Vol.51 No.10

Spodoptera frugiperda is considered a serious pest for many crops throughout the world. Here, we develop an easy and quick-to-prepare solid medium with multiple benefits, including reductions in cost, post-rearing waste, storage space, and labor, for rearing S. frugiperda larvae. The body length and weight at each development stage showed no differences with those of the corn leaves treatment group (P > 0.05). The development time of F0 generation from the first to adults stage was 51.27 ± 4.62 days when the larvae were reared on artificial diet, which is slightly longer than the 50.69 ± 4.56 days for those reared on corn leaves diet (P > 0.05). The temperature changes have no effect on body length and weight when the fall armyworms are reared on artificial diet, however, the influence of temperature change on development was more obvious. The development time was significantly longer at 18°C and shorter at 35°C than that at 25°C (P < 0.05). Furthermore, in the age-specific two-sex life table method, the life table parameters (i.e., r, λ, R0, GRR) significantly decreased at 18°C and 35°C compared with those at 25°C. The age–stage survival rate of S. frugiperda was higher on artificial diet at 25°C than 18°C, 35°C, and on corn leaves at 25°C in all stages. The 35°C temperature change had more influence on the age–stage survival than the other temperatures. This study provided ideal indoor breeding conditions for fall armyworm and sufficient materials for further indoor and outdoor research.

Electrospun Fibrous Silk Fibroin/Poly(L-Lactic Acid) Scaffold for Cartilage Tissue Engineering

Weiwei Liu,Zhengqiang Li,Lu Zheng,Xiaoyan Zhang,Peng Liu,Ting Yang,Bing Han 한국조직공학과 재생의학회 2016 조직공학과 재생의학 Vol.13 No.5

For successful tissue engineering of articular cartilage, a scaffold with mechanical properties that match those of natural cartilage as closely as possible is needed. In the present study, we prepared a fibrous silk fibroin (SF)/poly(L-lactic acid) (PLLA) scaffold via electrospinning and investigated the morphological, mechanical, and degradation properties of the scaffolds fabricated using different electrospinning conditions, including collection distance, working voltage, and the SF:PLLA mass ratio. In addition, in vitro cell-scaffold interactions were evaluated in terms of chondrocyte adhesion to the scaffolds as well as the cytotoxicity and cytocompatibility of the scaffolds. The optimum electrospinning conditions for generating a fibrous SF/PLLA scaffold with the best surface morphology (ordered alignment and suitable diameter) and tensile strength (~1.5 MPa) were a collection distance of 20 cm, a working voltage of 15 kV, and a SF:PLLA mass ratio of S50P50. The degradation rate of the SF/PLLA scaffolds was found to be determined by the SF:PLLA mass ratio, and it could be increased by reducing the PLLA proportion. Furthermore, chondrocytes spread well on the fibrous SF/PLLA scaffolds and secreted extracellular matrix, indicating good adhesion to the scaffold. The cytotoxicity of SF/PLLA scaffold extract to chondrocytes over 24 and 48 h in culture was low, indicating that the SF/PLLA scaffolds are biocompatible. Chondrocytes grew well on the SF/PLLA scaffold after 1, 3, 5, and 7 days of direct contact, indicating the good cytocompatibility of the scaffold. These results demonstrate that the fibrous SF/PLLA scaffold represents a promising composite material for use in cartilage tissue engineering.

A study on the cannibalism behaviour and predation of the larvae of fall armyworm (Spodoptera frugiperda)

Mbuji Amosi Leonard,Gong Xueyan,Li Fen,Yang Lei,Shi Xueyan,Peng Zhengqiang,Zhang Ying,Wu Shaoying 한국곤충학회 2022 Entomological Research Vol.52 No.5

Cannibalism behaviour in the Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is among of liming factor for mass production of the larvae for laboratory experiment. To understand the change of cannibalism, larvae of 1st, 2nd, and 3rd were used to study cannibalism they were put on the 3rd, 4th, and 5th larvae growth stages in a density of 30, 40, 50, 60, and 70. In this study, the results showed that the functional response of the 3rd -5th instar larvae to the 2nd larvae and the 4th–5th instar larvae to the 3rd larvae and 5th and 6th instar larvae to the 4th larvae fitted well with the Holling II mode. The maximum predation of the 3rd-5th instar larvae on the 2nd instar larvae were 27.17, 74.63, and 232.6 respectively, the maximum predation of the 4th–5th instar larvae on the 3rd instar larvae were 76.92 and 11.82 respectively, and the maximum predation of the 5th–6th instar larvae on the 4th instar larvae were 15.83 and 10.40. The predation of the older larvae to the younger larvae increased with the increase of the density of the younger larvae. This research aims at selecting the minimum number of larvae that will be effective and sustainable for laboratory experiments and minimizing the development of cannibalism in S. frugiperda, reduces crowding for larvae management and promoting healthy larvae. This study provides a pavement of managing larvae ensuring massive indoor larvae rearing to reduce the challenge of inadequate larva for the experiment.

GOCI Yonsei aerosol retrieval version 2 products: an improved algorithm and error analysis with uncertainty estimation from 5-year validation over East Asia

Choi, Myungje,Kim, Jhoon,Lee, Jaehwa,Kim, Mijin,Park, Young-Je,Holben, Brent,Eck, Thomas F.,Li, Zhengqiang,Song, Chul H. Copernicus GmbH 2018 Atmospheric measurement techniques Vol.11 No.1

<P><p><strong>Abstract.</strong> The Geostationary Ocean Color Imager (GOCI) Yonsei aerosol retrieval (YAER) version 1 algorithm was developed to retrieve hourly aerosol optical depth at 550&amp;thinsp;nm (AOD) and other subsidiary aerosol optical properties over East Asia. The GOCI YAER AOD had accuracy comparable to ground-based and other satellite-based observations but still had errors because of uncertainties in surface reflectance and simple cloud masking. In addition, near-real-time (NRT) processing was not possible because a monthly database for each year encompassing the day of retrieval was required for the determination of surface reflectance. This study describes the improved GOCI YAER algorithm version 2 (V2) for NRT processing with improved accuracy based on updates to the cloud-masking and surface-reflectance calculations using a multi-year Rayleigh-corrected reflectance and wind speed database, and inversion channels for surface conditions. The improved GOCI AOD <span class='inline-formula'><i>τ</i>_G</span> is closer to that of the Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) AOD than was the case for AOD from the YAER V1 algorithm. The V2 <span class='inline-formula'><i>τ</i>_G</span> has a lower median bias and higher ratio within the MODIS expected error range (0.60 for land and 0.71 for ocean) compared with V1 (0.49 for land and 0.62 for ocean) in a validation test against Aerosol Robotic Network (AERONET) AOD <span class='inline-formula'><i>τ</i>_A</span> from 2011 to 2016. A validation using the Sun-Sky Radiometer Observation Network (SONET) over China shows similar results. The bias of error (<span class='inline-formula'><i>τ</i>_G−<i>τ</i>_A)</span> is within <span class='inline-formula'>−</span>0.1 and 0.1, and it is a function of AERONET AOD and Ångström exponent (AE), scattering angle, normalized difference vegetation index (NDVI), cloud fraction and homogeneity of retrieved AOD, and observation time, month, and year. In addition, the diagnostic and prognostic expected error (PEE) of <span class='inline-formula'><i>τ</i>_G</span> are estimated. The estimated PEE of GOCI V2 AOD is well correlated with the actual error over East Asia, and the GOCI V2 AOD over South Korea has a higher ratio within PEE than that over China and Japan.</p> </P>