2017, 38(6).
Abstract:
YUAN Yexian , YU Lulu , LIAO Zhengrui , ZHU Canjun , CAI Xingcai , ZHU Xiaotong , JIANG Qingyan , SHU Gang , GAO Ping
2017, 38(6):1-8. DOI: 10.7671/j.issn.1001-411X.2017.06.001
Abstract:Objective To investigate the effects of long-term drinking water supplemented with lipopolysaccharide (LPS) on feeding, energy metabolism and behavior of mice.Method Totally 48 five-week-old C57/BL mice were randomly divided into eight groups. Different concentrations of LPS were injected intraperitoneally to test food intake. Meanwhile, 24 five-week-old C57/BL mice were randomly divided into three groups including control group without LPS, O128:B12 group (adding 5 μg·mL-1 Escherichia coil O128:B12 LPS to drinking water) and O55:B5 group (adding 5 μg·mL-1 E. coil O55:B5 LPS to drinking water). The experiment period was 12 weeks. Open field test and elevated plus-maze test were used to analyze the movement and anxiety behavior of mice. At the end of experiment, the body composition was tested and samples of fat tissue and brain nucleus were collected for gene expression analysis.Result Intraperitoneal injection of high dose LPS inhibited food intake of mice. Adding 5 μg·mL-1 LPS from different bacteria to drinking water significantly increased food intake of mice (P<0.05), and upregulated AgRP mRNA expression in the hypothalamic arcuate nucleus, while POMC mRNA expression was not affected. Drinking LPS significantly reduced feed efficiency, decreased fat deposition, and promoted the expression of UCP-1 and PGC-1ɑ in brown fat. Drinking LPS did not influence mouse anxiety behavior, but significantly promoted the locomotor activity of mice. Drinking LPS also significantly upregulated mRNA expression of c-fos and DRD2 in hippocampus.Conclusion Adding E. coli LPS to drinking water could improve mouse appetite, promote adipose metabolism of mice and increase locomotor activity of mice, which might be related to the increased activity of dopamine neurons in the hippocampus.
JIN Chenglong , FAN Hongbo , SUI Weiguo , YAN Huichao , WANG Xiuqi , GAO Chunqi
2017, 38(6):9-13. DOI: 10.7671/j.issn.1001-411X.2017.06.002
Abstract:目的 研究日粮添加赖氨酸(Lysine,Lys)和盐酸吡格列酮(Thiazolidinedione,TZD)对肥育猪生产性能、血清生化指标及肉品质的影响。方法 选用160头体质量均一[体质量=(92.25±0.91)kg]、健康的杜×长×大三元杂肥育猪,随机分成4个处理,每个处理5个重复,每个重复8头猪(公母各半)。对照组饲喂基础日粮[w(Lys)为0.85%],试验组Ⅰ为基础日粮+15 mg·kg-1 TZD,试验组Ⅱ为基础日粮+w为0.20% Lys+15 mg·kg-1 TZD,试验组 Ⅲ 为基础日粮+w为0.40% Lys+15 mg·kg-1 TZD。试验结束后从对照组和试验组 Ⅲ 每重复选取1头公猪进行屠宰,评定其屠宰性能及肉品质。结果 与对照组相比,在第28天,试验组 Ⅲ 日增质量提高9.45%(P=0.055);在第14天,试验组 Ⅲ 血清高密度脂蛋白含量显著高于对照组,提高了22.81%(P<0.05);在第28天,试验组 Ⅲ 瘦肉率及背最长肌肉色红度(a* 值)均显著高于对照组,分别提高了7.04%和4.11%(P<0.05)。结论 日粮添加Lys质量分数为0.40%(总Lys质量分数为1.25%)和15 mg·kg-1的TZD可增加肥育猪的日增质量和瘦肉率,并改善肌肉的红度。
ZHANG Shanshan , WU Min , ZHANG Xiaoyin , LAN Hainan , ZHENG Xin
2017, 38(6):14-19. DOI: 10.7671/j.issn.1001-411X.2017.06.003
Abstract:Objective To investigate the effect of astaxanthin on H2O2-induced oxidative stress response in primary mouse hepatocytes.Method Primary mouse hepatocytes were isolated by an in situ two-step perfusion technique. The model of oxidative stress response in primary mouse hepatocytes was established using H2O2 treatment and malondialdehyde(MDA) as an indicating index. The content of reative oxygen species (ROS) and change in apoptosis rate were measured by flow cytometry. The contents of MDA and glutathione(GSH), and the activities of superoxide dismutase(SOD) and glutathione peroxidase(GSH-px) were measured by biochemical methods. The relative mRNA expression levels of antioxidant enzymes including SOD and GSH-px were measured by fluorescence quantitative PCR. The relative expression of Nrf2 protein was measured by Western-blot.Result The model of oxidative stress response performed the best with the primary mouse hepatocytes pre-protected by 5 μg·mL-1 astaxanthin for 3 h before being exposed to 10 μmol·L-1H2O2 for 3 h. Astaxanthin decreased the apoptosis rate and the contents of ROS, MDA and GSH in primary mouse hepatocytes induced by H2O2. Astaxanthin increased the activities of SOD and GSH-px as well as the relative mRNA expression levels of SOD and GSH-px, and inhibited the nuclear transfer of Nrf2 protein.Conclusion Astaxanthin has protective effects on H2O2-induced primary mouse hepatocytes with oxidative stress.
WANG Fang , LIU Chun , JIANG Lan , FENG Yongyong , LI Kaibin
2017, 38(6):20-26. DOI: 10.7671/j.issn.1001-411X.2017.06.004
Abstract:Objective To study the characteristics of transparent tiger barb Puntius tetrazona infected with Mycobacterium marinum and develop an infection model.Method P. tetrazona were infected with M. marinum via intraperitoneal injection, intramuscular injection and cohabitation experiment. The fish characteristics after infection were observed. Distribution of bacteria and pathological changes in the fish were evaluated by wet-mount preparations and tissue slices.Result Both injection methods resulted in pathologic damages around the infection sites, and gradually led to fish death. The disease progression was slow for the fish in the cohabitation experiment, and the fish appeared thin and pale. The pathogenic bacteria were isolated from fish with different infection treatments. Granulomas, the classic symptom for infection, were observed in major organs. M. marinum could be specifically stained by Ziehl-Neelsen stain. A number of melano-macrophage centers developed in different organs, and the organs were associated with different degrees of pathologic lesion.Conclusion The transparent line of tiger barb is a susceptible host of M. marinum, and the symptoms can be conveniently observed with typical pathological changes. P. tetrazona is an excellent model for further infection research.
LUO Yangyang , ZHAO Lichan , LI Qunhui , LIN Ruiqing , WENG Yabiao
2017, 38(6):27-33. DOI: 10.7671/j.issn.1001-411X.2017.06.005
Abstract:Objective To isolate and identify the pathogen causing the inclusion body hepatitis (IBH) and hydropericardium syndrome (HPS) in chicken in Guangdong Province, and study its molecular characteristics.Method A virus was isolated from specific pathogen-free(SPF) chicken embryo inoculated with liver suspension from affected chickens. The virus was purified by limiting dilution method and used for pathogenicity test. Hexon, fiber-2, ORF29 and ORF19 genes were amplified by PCR, and analyzed for molecular characteristics.Result Sequence analysis of hexon gene revealed the strain, named as WM-XC, belonged to group I fowl adenovirus serotype 4 (FAdV-4). This isolated strain was pathogenic based on the evidence that the mortality rate of SPF chicken reached 90% after virus inoculation, the hydropericardium-hepatitis syndrome was observed, and acidophilous inclusion body was found in the pathological section of liver. The fiber-2 gene sequence of WM-XC had 96.1% and 97.0% similarities with the corresponding sequences of ON1 and KR-5, and had 100% similarity with fiber-2 genes of fowl adenovirus isolates collected in China since 2015. There was a 33 bp deletion in ORF29 gene of WM-XC compared with JSJ13 and JN13 strains isolated in 2013 in China. Similar to isolates collected in China since 2015, WM-XC lacked ORF19 compared with classical FAdV-4 strain ON1 and KR-5.Conclusion The isolated group I FAdV-4 strain and other isolates collected in China in recent years were distinct from classical FAdV-4 strains in their fiber-2, ORF19 and ORF29 gene sequences.
LI Xiaojuan , LIANG Kaiming , ZHONG Xuhua , TIAN Ka , PENG Shaobing , HUANG Nongrong , PAN Junfeng , LIU Yanzhuo
2017, 38(6):34-43. DOI: 10.7671/j.issn.1001-411X.2017.06.006
Abstract:Objective To explore the effects of light intensity during internode elongation on rice (Oryza sativa L.) lodging resistance.Method Rice plants were subjected to different light intensities in phytotrons at the 1st (S1), 2nd (S2), 3rd (S3) and 1st to 3rd (S123) internode elongation stages. The lodging resistance of rice stem and the morphological and material mechanical traits of basal internodes were measured.Result The lodging index (LI) of rice stem significantly decreased with the increasing of light intensity. LI of medium or high light intensity treatments was 34.8%-73.9% lower than that of low light intensity treatment at the S123 internodes elongation stage. LI was significantly positively correlated with internode length, and negatively correlated with internode diameter, culm wall thickness and internode plumpness. The S2 stage was the most sensitive period of lodging resistance to light intensity variation. Light intensity had accumulative effects on lodging resistance. The variation coefficient of lodging index at the S123 stage was greater than those at the S1, S2 and S3 stages, and similar results were found in most morphological and material mechanical traits.Conclusion The key factors to determine the lodging resistance are internode length, culm wall thickness and internode plumpness. Light intensity can significantly change the three morphological traits of basal internodes, which further affect the material mechanical characteristics of rice stem and lodging resistance.
CHEN Zhanyu , FU Liangshuai , ZHANG Yujiao , LI Dayong , CUI Xiyan , ZHANG Zhi'an
2017, 38(6):44-50. DOI: 10.7671/j.issn.1001-411X.2017.06.007
Abstract:Objective To explore changes of nitrogen and nutrient element contents of root bleeding saps of soybeans [Glycine max (L.) Merr.] with different yield levels at late growth stages, and provide a physiological basis for soybean breeding and high-yielding cultivation.Method Soybean cultivars with three different yield levels (low-, middle- and high-yielding) were planted under the same cultivation condition. Root bleeding intensity, the contents of nitrogen compounds (total nitrogen, nitrate nitrogen, ammonium nitrogen and amino acids) and other nutrient elements (P, K, Ca and Na) in root bleeding saps of soybeans were measured at flowering (R2), podding (R4) and seed-filling (R6) stages respectively.Result Root bleeding intensities, total nitrogen and amino acid contents of high-yielding cultivars were 13.4% and 24.0%, 31.9% and 74.2%, 46.3% and 81.0% higher than those of middle- and low-yielding cultivars at late growth stages. Nitrate nitrogen content of high-yielding cultivar was 19.9% higher than that of low-yielding cultivar,while ammonium nitrogen content of high-yielding cultivar was 16.5% lower than that of low-yielding cultivar. The P, K and Ca contents of high-yielding cultivar were higher than those of low- and middle-yielding cultivars. The bleeding intensities of soybeans with different yield levels reached the maxinum values at R4 stage, and the grain yield was significantly positively correlated with bleeding intensity at R4 stage (r = 0.765**). The contents of total nitrogen and amino acid in root bleeding saps reached the maximum values at R2 stage while the contents of P and K were the highest at R4 stage.Conclusion Root metabolism of high-yielding cultivar was vigorous and had stronger absorption capacity and vitality, which might be the key factors to increase soybean yield.
YAO Chunjuan , XIONG Guangkang , YANG Xiaohua , LAI Xiaolian , GUO Shengmao , LI Zhaoshuang
2017, 38(6):51-57. DOI: 10.7671/j.issn.1001-411X.2017.06.008
Abstract:Objective To explore the fertilizer requirement of Rubus chingii, and provide a theoretical reference and guidance for its high quality and high yield cultivation in the future.Method The effects of different fertilizers fertilizing amounts [low (L), medium (M) and high (H) levels] on the chlorophyll, plant height, chlorophyll fluorescence parameters and related physiological indexes of R. chingii were studied by pot experiment.Result Chlorophyll content, plant height, chlorophyll fluorescence parameters and physiological indexes increased with the increase of fertilization amount. Compared with control, the increases of chlorophyll content under NPK fertilization were stable, being 36.3%, 41.3% and 53.4% under L, M and H levels of NPK fertilization, and differences among NPK levels were significant. Compound fertilization significantly increased chlorophyll content, but there was no significant difference among different levels of compound fertilizer. Chlorophyll content was not significantly different between M and H levels of organic fertilizer. There was highly significant correlation between NPK fertilization levels and plant height. Plant heights under NPK fertilization were the highest, the increases were 40.5%, 50.2% and 64.4%, followed by 18.3%, 44.0% and 56.2% with organic fertilization, and then 16.1%, 20.3% and 40.7% with compound fertilization. At different fertilization levels, NPK fertilization resulted in the highest levels of Fv/Fm, ΦpsⅡ and qP. Compound fertilization and organic fertilization levels had significant correlation with four chlorophyll fluorescence parameters. Among three fertilization treatments, qP was the lowest under compound fertilization, while Fv/Fm and ΦpsⅡ were the lowest under organic fertilization. NPK fertilization level had significant correlation with four physiological indexes. At different fertilization levels, NPK fertilization resulted in the highest contents of soluble protein, soluble sugar and proline, and the lowest MDA content. At H level of compound fertilization, the increases of soluble protein and soluble sugar contents were 8.4% and 2.1% respectively, which were the lowest. At H level of organic fertilization, the increases of MDA content was 36.8%, which was the highest.Conclusion With the increase of fertilization levels, the chlorophyll content and plant height of R. chingii significantly increased under NPK fertilization, and the chlorophyll fluorescence parameters and physiological indexes also had desirable values.
YUAN Zhongyou , LIANG Zhonglong , YANG Qijun , LIU Qing , WU Jialong , DAI Jun
2017, 38(6):58-63. DOI: 10.7671/j.issn.1001-411X.2017.06.009
Abstract:Objective To study the short-term effects of different fertilizers on microbial characteristics and enzyme activities of lateritic soil degraded by highway construction.Method Greenhouse pot experiments were performed using Neyraudia reynaudiana. The lateritic soil degraded by highway construction was used as control(CK). Three fertilization treatments included chemical fertilizer(HF) with the same NPK degree as vermicompost, cattle manure (NF) and vermicompost (YF). The effects of different treatments on soil microbial characteristics and enzyme activities were investigated by principal component analysis.Result Compared with HF treatment, soil microbial biomass carbon, microbial biomass nitrogen, soil respiration, amounts of metabolic entropy, bacteria, fungi and actinomycetes significantly increased by 70%, 96%, 1 239%, 699%, 300%, 1 155% and 272% respectively in NF treatment, and increased by 80%, 130%, 1 458%, 773%, 295%, 324% and 285% respectively in YF treatment(P<0.05). Soil invertase, urease, catalase, acid phosphatase, β-glucosidase, acetylglucosaminidase, polyphenol oxidase and peroxidase activities significantly increased by 61%, 37%, 36%, 119%, 259%, 1 973%, 175% and 550% respectively in NF treatment, and increased by 66%, 40%, 52%, 128%, 302%, 1 641%, 182% and 428% respectively in YF treatment (P<0.05).Conclusion In short-term, applying organic fertilizer such as cattle manure and vermicompost is better than using chemical fertilizer for improving soil microbial properties, enhancing soil enzyme activities and improving comprehensive quality of soil degraded by construction. NF and YF treatments have no significant differences in their effects on soil microbial properties and enzyme activities. Applying organic fertilizer is an effective way to repair rapidly the soil degraded by construction.
WU Wei , WANG Zuowei , SU Yongying , GAN Shuang , DU Shiping , CAI Yi , GUO Jinya
2017, 38(6):64-71. DOI: 10.7671/j.issn.1001-411X.2017.06.010
Abstract:Objective To study the subcellular localization signals of cytokinin receptors and related mechanisms.Method A series of expression vectors for subcellular localization of Arabidopsis histidine protein kinase 3 (AHK3), one of cytokinin receptor proteins in Arabidopsis, were constructed and transformed into Arabidopsis protoplast cells for transient expression. Laser confocal microscope was used to observe the subcellular localization of AHK3 protein.Result AHK3 is localized in endoplasmic reticulum(ER). Both N and C terminals contain ER localization sequences.Conclusion AHK3 carry out its functions in ER, such as perception of cytokinin, downstream signal transduction and interactions with other receptor proteins, and AHK3 contains multiple ER localization signals.
HE Yuguang , ZHOU Si , HU Xiaoyun , LIAO Meide
2017, 38(6):72-78. DOI: 10.7671/j.issn.1001-411X.2017.06.011
Abstract:Objective To study the effects of surfactants on fermentation of Streptomyces galilaeus AF1 strain.Method The single factor experiments were performed to optimize the surfactant type and the initial concentration and determine the best adding time. The Box-Behnken test design and response surface analysis were used to determine the most appropriate concentrations of surfactants. Flow cytometer instrument was used to measure the cell fluorescence intensity and investigate the effects of surfactant on cell membranes of AF1.Result The optimum concentrations of added surfactants were 8.95 g·L-1 Tween-80, 2.09 g·L-1 Triton X-100 and 3.89 g·L-1 sorbitol. The best adding time was five days after inoculation. The membrane permeability test results showed that the cell fluorescence intensity of AF1 of the test group was significantly higher than that of the control group.Conclusion The response surface model explained 94.89% of the variation in the dependent variables and therefore had practical significance. Membrane permeability of the AF1 strain significantly increased after adding the optimal surfactants complex, which led to increased efflux of intracellular active substance and biosythesis of antibacterial substance.
FANG Xuyuan , XIA Gaofeng , SHI Qiaoqiao , HE Can , YANG Xiaoyun , XU Hanhong
2017, 38(6):79-83. DOI: 10.7671/j.issn.1001-411X.2017.06.012
Abstract:Objective To establish a method for analyzing herbicide residues in Angelica sinensis.Method The residues of nine herbicides, including fenamine, clomazone, acetochlor, prometryn, metolachlor, pendimethalin, butachlor, pretilachlor and oxyfluorfen were analyzed by QuEChERS combined with GC-MS. Samples were extracted with acetonitrile and cleaned up using primary secondary amine (PSA) and graphitized carbon black (GCB). Nine herbicides were detected using the selective ion monitoring (SIM) mode and quantified with external standards. Parameters which influenced extraction and purification efficiency were optimized.Result There were good linear relationships between herbicide concentration and detected peak area within the range from 0.01 to 5.00 mg·L-1 for all nine herbicides. The average recovery rates of nine herbicides in A. sinensis were from 74.58% to 96.37% at the addition levels of 0.01 and 0.10 mg·kg-1, with relative standard deviation less than 11.73%. The detection limits of nine herbicides were from 0.52 to 6.60 μg·kg-1.Conclusion This detection method is simple, fast and effective, and can be used practically to detect a variety of herbicides in A. sinensis samples.
LI Yihan , ZHOU Yating , SHEN Zule , QIU Baoli
2017, 38(6):84-88. DOI: 10.7671/j.issn.1001-411X.2017.06.013
Abstract:Objective To study the ontogenetic morphology and parasitic behavior of Tamarixia radiata, the predominant parasitoid of Diaphorina citri, and provide theoretical and technical information for sustainable management of Huanglongbing.Method The parasitic behavior and ontogenetic morphology of T. radiata were observed under laboratory conditions of (26±1) ℃ and 60% to 80% relative humility and natural lighting. Morphologic indexes of T. radiata were measured.Result The adult T. radiata females lay eggs on 3rd to 5th instar nymphs of D. citri. The life cycle of T. radiata includes the egg, larva, pupa and adult stages. The developmental duration is about 13.40 d under laboratory condition. The females are distinctly larger than males in body size. The setae of male antennas are well developed and almost cover all the antenna segments, while the setae of female antennas are short and the antenna segments are clearly visible. The yellow area on the dorsal surface of female abdomen is obviously larger than that of male.Conclusion T. radiata is an ecto-parasitoid of D. citri. There are significant morphological differences between T. radiata female and male adults.
MAO Yuting , ZHANG Meng , JIN Xiufang , MA Tao , WANG Cai , SUN Chaohui , CHEN Xiaoyang , LI Yizhen , WEN Xiujun
2017, 38(6):89-96. DOI: 10.7671/j.issn.1001-411X.2017.06.014
Abstract:Objective Heortia vitessoides is an important defoliator attacking the precious tree species of Aquilaria sinensis. The goal was to screen potential insect-resistant plants by surveying A. sinensis victimization in a large area of forest, and provide a basis for the scientific prevention of H. vitessoides and the breeding of insect-resistant plants.Method In the harmful period of H. vitessoides, regular surveys on large area of A. sinensis forests were conducted. In the seriously damaged A. sinensis forests, plant appearances and leaf physical structures at different levels of victimization were observed, and leaves from different insect-resistant plants were collected to feed the newly-hatched larvae of H. vitessoides. Whether the leaves from different insect-resistant plants were chosen or rejected by the larvae was observed. The differences in larva survival rate, growth and development, pupation and feathering by feeding on different resistant A. sinensis leaves were tested.Result There were two undamaged A. sinensis plants in the severely damaged A.sinensis forests, showing good resistance to insect pests (anti-1 and anti-2). There were significant differences in leaf length and thickness between the insect-resistant plants (anti-1 and anti-2) and susceptible plants(P<0.05), while the ratio of leaf length to width had no significant difference. As for leaf physical structures, the leaf upper epidermis cuticle thickness of anti-2 was significantly higher than that of the susceptible plant. The antifeedant rate of H. vitessoides larvae against anti-2 plant was significantly higher than that against anti-1 plant, and both were above 44.81%. Larvae fed on resistant leaves had significant lower survival rate, adult emergence rate, pupal weight and shorter adult longevity, but longer duration of pupa compared to larvae fed on normal A. sinensis leaves.Conclusion A. sinensis plants with tender green leaves are more susceptible to H. vitessoides, while the plants with thick, yellow or dark green leaves have strong resistance to H. vitessoides. Resistant A. sinensis plants have a higher inhibitory effect on feeding activity of H. vitessoides larvae and hinder larval development.
ZHENG Xinying , CAI Jinhuan , XUE Li , SHE Hanji
2017, 38(6):97-104. DOI: 10.7671/j.issn.1001-411X.2017.06.015
Abstract:Objective To investigate the effects of external nitrogen(N) and phosphorus(P) on decomposition rate of mixed leaf litters of Michelia macclurei and Pinus massoniana woodlands, and analyze changes in N,P and potassium(K) contents during deposition process, in order to understand the response mechanism of leaf litter decomposition to external N and P, and provide reference for forest resource management.Method Mixed leaf litters of M. macclurei and P. massoniana were placed in woodlands of M. macclurei and P. massoniana. Four 5 m×5 m plots were set in each wood land and were sprayed with N, P or N+P. The decomposition rates and changes in N, P, K contents of leaf litters were compared.Result Twenty-four months after treatments, the amounts of leaf litter residue were N addition (4.99 g) > control (4.14 g) > N+P addition (2.17 g) > P addition (1.16 g) in M. macclurei woodland, and N addition (2.72 g) > control (1.21 g) > N+P addition (0.36 g) > P addition (0.16 g) in P. massoniana woodland. N addition inhibited decomposition of mixed leaf litters under M. macclurei and P. massoniana woodlands, whereas P and N+P additions both accelerated decomposition of mixed leaf litters with a faster decomposition rate compared to N+P addition. The amounts of leaf litter residue in P. massoniana woodland were less than those in M. macclurei woodland. Twenty-four months after treatments, N contents of mixed leaf litters treated with N, P and N+P additions were 13.72, 12.34 and 13.70 g·kg-1 respectively in M. macclurei woodland, and 12.63, 13.46, and 14.54 g·kg-1 respectively in P. massoniana woodland, Which were greater than the initial N content of mixed leaf litters (9.90 g·kg-1). The P content of mixed leaf litters treated with P and N+P additions increased from the initial value of 0.38 to 0.86 and 0.74 g·kg-1 respectively in M. macclurei woodland, and increased from 0.38 to 1.37 and 1.05 g·kg-1 respectively in P. massoniana woodland. K contents of mixed leaf litters changed irregularly.Conclusion Decomposition of M. macclurei leaf litter can be accelerated and decomposition rate of mixed leaf litters can be enhanced by mixed-planting M. macclurei and P. massoniana.
2017, 38(6):105-111. DOI: 10.7671/j.issn.1001-411X.2017.06.016
Abstract:Objective To make an agricultural robot accurately find a path without collision in complex and dynamic environment in real time.Method Using online uncertainty reasoning based on a cloud model, a dynamic guidance A* algorithm based on the cloud model (CDGA*) was proposed to realize human-machine cooperative path planning. Human's expertise and preferences were incorporated into the DGA* optimization process to implement a faster path planning. Matlab software was used to simulate and analyze the CDGA* and DGA* algorithms.Result In static path planning, the numbers of close points of the DGA* and CDGA* algorithms were 158 and 96, human planning time was 8.8 and 4.0 s, the total planning time was 15.6 and 8.9 s, respectively. In dynamic path planning, human planning time of the DGA* and CDGA* algorithms was 12.5 and 5.8 s, the total planning time was 23.3 and 14.6 s, respectively.Conclusion The proposed CDGA* algorithm can largely decrease the number of nodes, reduce computation time and improve planning efficiency.
JIANG Zhilin , WANG Jiasheng , LI Jiawei , CHEN Yan , LIU Weiwei , ZOU Xiangjun , ZENG Zeqin
2017, 38(6):112-117. DOI: 10.7671/j.issn.1001-411X.2017.06.017
Abstract:Objective To reduce the drop collision damages during litchi picking by robot due to improper placement and recycling.Method The drop collision experiment of litchi was performed. The influences of different drop collision conditions on weight loss and pericarp browning indexes of litchi were analyzed.Result The weight loss and pericarp browning indexes of litchi both increased with the dropping height of picking and placing and increased with the storage time. At the same dropping height, the weight loss and pericarp browning indexes of litchi were the highest when the impact contact material was PVC slab at collision. Within the scope of the experiment, it was conducive to reducing drop collision damages of litchi using the following maximum initiative dropping heights during the picking and placing process by robot: 60 cm after 2 d storage and 30 cm after one week storage when the recycling device was made from PVC plastic; 75 cm after 2 d storage and 45 cm after one week storage when the recycling device was made from corrugated board; 90 cm after 2 d storage and 60 cm after one week storage when the bottom of the recycling device was filled with litchi.Conclusion The research can provide guidance for developing strategies to decrease damage during the litchi picking and placing process based on robot.
LUO Juchuan , WEN Sheng , LI Hanguang , LIU Qingting , ZHU Hongyun
2017, 38(6):118-124. DOI: 10.7671/j.issn.1001-411X.2017.06.018
Abstract:Objective To provide a theoretical basis for designing a device cutting sugarcane tail stalk and establishing a mathematical model for dynamic simulation.Method The precision micro control electronic universal testing machine and static resistance strain gauge were used to perform tensile tests on sugarcane skin, core and joints of the fifth and sixth sections below the growing points of sugarcane tail stalk. The Poisson's ratio parameters of each component were obtained by electrometric method and mechanical analysis.Result The PRXY of sugarcane skin and core of the fifth section below the growing points of sugarcane tail stalk was less than 0.028 and 0.174, and the NUXY was 0.233 and 0.271, respectively. The PRXY of sugarcane skin and core of the sixth section below the growing points was less than 0.001 and 0.223, and the NUXY was 0.238 and 0.289 respectively. The PRXY of sugarcane joint was less than 0.305 and the NUXY was 0.344.Conclusion The PRXY has significant differences among different parts of the sugarcane tail stalk, while the NUXY has little difference. Sugarcane skin and core both have significant differences in PRXY between the fifth and sixth sections below the growing points of sugarcane tail stalk, which has no significant difference in NUXY.
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