Guojun Ma

Prof. Dr. Guojun Ma


Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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20 March 2023 in Foods
Verified
Journal Article
Open access
PDF file
YYYuanman Yue
Yuanman Yue
QZQian Zhang
Qian Zhang
FWFangxin wan
Fangxin wan
GMGuojun Ma
Guojun Ma
ZZZepeng Zang
Zepeng Zang
XHXiaopeng Huang
Xiaopeng Huang
The present study aimed to investigate the effect of rotary microwave vacuum drying (RMVD), radio frequency vacuum drying (RFVD), vacuum far infrared drying (VFID), vacuum drying (VD), hot air drying (HD) and natural drying (ND) on the drying characteristics, active ingredients and microstructure of Codonopsis pilosulae slices. Compared with the fitting results of the four models, the Weibull model is the most suitable drying model for Codonopsis. The RFVD and HD color difference values were smaller compared to ND. The effective moisture diffusivity (Deff) under different drying methods was between 0.06 × 10−8 m2/s and 3.95 × 10−8 m2/s. RMVD-dried products had the shortest drying time and retained more active ingredients. The microstructure analysis revealed that the porous structure of RMVD is more favorable for water migration. RMVD is a promising dehydration method for obtaining high-value-added dried Codonopsis products.

18 March 2022 in Foods
Verified
Journal Article
Open access
PDF file
XHXiaopeng Huang
Xiaopeng Huang
FWFangxin Wan
Fangxin Wan
ZZZepeng Zang
Zepeng Zang
QZQian Zhang
Qian Zhang
GMGuojun Ma
Guojun Ma
XHXiaopeng Huang
Xiaopeng Huang
In this study, the effect of an ultrasound (US) pre-treatment on the process of drying Cistanche slices through far-infrared vacuum drying was investigated with various experimental factors, including the US treatment time (25, 35, 45 min), frequency (20, 40, 60 kHz) and power (150, 180, 210 W). The results showed that compared with the samples without US, the material drying time after the US treatment was reduced by 16–36.8%. The effective moisture diffusion coefficients of Cistanche slices under different US conditions ranged from 1.61122 × 10−8 to 2.39274 × 10−8 m2/s, which agreed with food processing ranges. In addition, the phenylethanoid glycoside, iridoid, polysaccharide, total phenol and total flavonoid contents in Cistanche were significantly increased after US pre-treatment. However, the dried products obtained with the 45 min US treatment had greatly damaged internal structures, collapsed and seriously deformed surfaces, and low contents of active ingredients. Overall, the US pre-treatment could significantly improve the drying quality of Cistanche slices.

26 April 2024 in Agriculture
Verified
Journal Article
Open access
PDF file
CHCuncai He
Cuncai He
FWFangxin wan
Fangxin wan
GMGuojun Ma
Guojun Ma
XMxiaobin mou
xiaobin mou
KZKaikai Zhang
Kaikai Zhang
XHXiaopeng Huang
Xiaopeng Huang
In response to the issues of missed detection, false positives, and low recognition rates for specific weed species during weed detection, a YOLOv8-based improved weed detection algorithm named EDS-YOLOv8 is proposed. Improvements were made in three main aspects. First, the YOLOv8 backbone network was enhanced with EfficientViT and RepViT architectures to improve the detection capability of dense-type weeds. Second, different attention mechanisms were added, such as SimAM and EMA, to learn 3D weights and achieve full fusion of features. BiFormer was introduced for dynamic sparse attention and resource allocation. Third, significant module improvement involved introducing dynamic snake convolution into the C2f module to further enhance detection capabilities for deformable objects, especially needle-shaped weeds. The improved model is validated on the established weed dataset. The results show that combining the original backbone network with dynamic snake convolutions yields the highest performance improvement. Precision, recall, mAP (0.5), and mAP (0.5:0.95) are improved by 5.6%, 5.8%, 6.4%, and 1%, respectively, and ablation experiments on the effects of the three improvement methods on model performance show that using EfficientViT as the backbone network while simultaneously improving the crucial module and adding the SimAM attention mechanism effectively enhances the model’s performance. Precision, recall, mAP (0.5), and mAP (0.5:0.95) are improved by 6%, 5.9%, 6.4%, and 0.7%, respectively.

31 March 2024 in Agriculture
Verified
Journal Article
Open access
PDF file
BWBowen Wu
Bowen Wu
GMGuojun Ma
Guojun Ma
FWFangxin wan
Fangxin wan
JMJunmin Ma
Junmin Ma
ZZZepeng Zang
Zepeng Zang
XHXiaopeng Huang
Xiaopeng Huang
This study applied direct-contact ultrasound-assisted Vacuum Far-Infrared (VFIR) to dry Cistanche slices, investigating the influence of radiation temperature (45 °C, 55 °C, 65 °C), ultrasonic frequency (20 kHz, 40 kHz, 60 kHz) and ultrasonic power (72 W, 96 W, 120 W) on the physicochemical properties, drying characteristics, and microstructure of Cistanche slices. The results showed that the application of ultrasound had a significant enhancement effect on the drying process, with drying time decreasing as radiation temperature, ultrasonic power, and ultrasonic frequency increased. The drying rate curves under three experimental factors exhibited a brief acceleration stage followed by a deceleration stage. Under different drying conditions, the contents of Iridoid and phenylethanoid glycosides in dried products were higher than those under natural drying (ND). Specifically, the content of catalpol at 55 °C, 96 W, 40 kHz (0.56 mg/g) and the content of Leonuride at 55 °C, 96 W, 60 kHz (0.67 mg/g) increased by 1.81 and 1.9 times, compared to ND. The rest of the nutrient content and antioxidant activity increased with the increase in ultrasonic frequency. Compared to ND, ultrasonic-assisted VFIR drying improved the color and rehydration capacity of dried products. Observation of the microstructure revealed that the application of ultrasound made the interior of Cistanche slices loose and porous. In summary, ultrasonic-assisted VFIR drying not only enhances the drying rate but also improves the quality of dried products.

24 July 2023 in Agriculture
Verified
Journal Article
Open access
PDF file
XMxiaobin mou
xiaobin mou
QLQi Luo
Qi Luo
GMGuojun Ma
Guojun Ma
FWFangxin wan
Fangxin wan
CHCuncai He
Cuncai He
XHXiaopeng Huang
Xiaopeng Huang
In the process of orchard mechanization, passability serves as a crucial criterion for evaluating the effectiveness of the chassis. To address the adaptability of hilly and mountainous multifunctional work machines to complex terrain, a theoretical analysis was conducted to assess the chassis’ performance under three key working conditions: climbing, crossing obstacles, and crossing trenches. Using kinematics, the theoretical maximum climbing angle, maximum obstacle height, and maximum trench width were calculated to be 35.8°, 170.4 mm, and 427 mm, respectively. Additionally, the passability of the chassis model was simulated under these working conditions in different soil environments using RecurDyn dynamics software. Post-processing techniques were employed to extract time characteristic curves for parameters such as center-of-mass velocity, pitch angle, offset, lateral inclination angle, and longitudinal displacement, providing valuable insights into how these parameters changed during chassis movement. The results revealed that the maximum gradient for slope climbing was 30°, the maximum height for obstacle crossing was 150 mm, and the maximum width for trench crossing was 400 mm. The prototype was then tested under these theoretical and simulated conditions in the field, and its ability to smoothly traverse slopes with a 35° angle in first gear, climb vertical obstacles up to a height of 200 mm, and pass through trenches with a width of 430 mm was demonstrated. The crawler chassis exhibited stable performance within the design parameters, aligning closely with the simulated and theoretical expectations. Overall, this study provides valuable theoretical insights for the structural design of multipurpose chassis suitable for orchards in hilly and mountainous regions.

24 August 2024 in Foods
Verified
Journal Article
Open access
PDF file
ACAo Chen
Ao Chen
FWFangxin wan
Fangxin wan
GMGuojun Ma
Guojun Ma
JMJunmin Ma
Junmin Ma
YXYanrui Xu
Yanrui Xu
XHXiaopeng Huang
Xiaopeng Huang
To fully leverage the advantages of both hot air drying and radio frequency vacuum drying, a segmented combination drying technique was applied to post-harvest Cistanche. This new drying method involves using hot air drying in the initial stage to remove the majority of free water, followed by radio frequency vacuum drying in the later stage to remove the remaining small amount of free water and bound water. During the radio frequency vacuum drying (RFV) phase, the effects of temperature (45, 55, and 65 °C), vacuum pressure (0.020, 0.030, and 0.040 MPa), plate spacing (65, 75, and 85 mm), and slice thickness (4, 5, and 6 mm) on the drying characteristics, quality, and microstructure of Cistanche slices were investigated. Additionally, infrared thermal imaging technology was used to examine the surface temperature distribution of the material during the drying process. The results showed that compared to radio frequency vacuum drying alone, the hot air–radio frequency combined drying significantly shortened the drying time. Under conditions of lower vacuum pressure (0.020 MPa), plate spacing (65 mm), and higher temperature (65 °C), the drying time was reduced and the drying rate increased. Infrared thermal imaging revealed that in the early stages of hot air–radio frequency vacuum combined drying, the center temperature of Cistanche was higher than the edge temperature. As drying progressed, the internal moisture of the material diffused from the inside out, resulting in higher edge temperatures compared to the center and the formation of overheating zones. Compared to natural air drying, the hot air–radio frequency vacuum combined drying effectively preserved the content of active components such as polysaccharides (275.56 mg/g), total phenols (38.62 mg/g), total flavonoids (70.35 mg/g), phenylethanoid glycosides, and iridoids. Scanning electron microscopy observed that this combined drying method reduced surface collapse and cracking of the material. This study provides theoretical references for future drying processes of Cistanche.