A trajectory planning method for sprawling robot inspired by a trotting animal

Hongkai Li,Aiju Shi,Zhendong Dai 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.1

Motion coordination is a key factor affecting the stability and efficiency of robots. Such coordination involves the intra-limb coordination between each motion stage of a single leg and the inter-limbs coordination among all legs. The motion behaviors of animals, which have developed over a long period of evolution, offer good prototypes for the motion control of robots. In this paper, the locomotion of a quadruped sprawling animal (i.e., gecko) trotting on a horizontal surface was observed, and the feet trajectories around the hip on the same side were analyzed by statistical analysis and curve fitting. Results showed that feet on stance phase maintain the same speed to satisfy the requirement of inter-limb coordination. In swing phase, feet speed decreases from the moving speed to zero at the beginning and increases from zero to the desired speed in the next step at the end. The feet accomplish the transition from the backmost to the foremost position along a smooth curve that can be fit by a cosine function, which has good kinematic and dynamic characters. A foot trajectory planning method for robots was proposed based on the experiment results, which offered references not only for the foot trajectory planning of robots to realize intra-limb coordination but also for the inter-limbs coordination between stance feet during locomotion. Finally, the motion of a sprawling robot is simulated by using the bio-inspired trajectories to show the performance and benefits of the proposed method.

Lipids, Anthropometric Measures, Smoking and Physical Activity Mediate the Causal Pathway From Education to Breast Cancer in Women: A Mendelian Randomization Study

Hongkai Li,Lei Hou,Yuanyuan Yu,Xiaoru Sun,Xinhui Liu,Yifan Yu,Sijia Wu,Yina He,Yutong Wu,Li He,Fuzhong Xue 한국유방암학회 2021 Journal of breast cancer Vol.24 No.6

Purpose: We aimed to investigate whether obtaining a higher level of education was causally associated with lower breast cancer risk and to identify the causal mechanism linking them. Methods: The main data analysis used publicly available summary-level data from 2 large genome-wide association study consortia. Mendelian randomization (MR) analysis used 65 genetic variants derived from the Social Science Genetic Association Consortium as instrumental variables for years of schooling. The outcomes from the Breast Cancer Association Consortium (BCAC) were the overall breast cancer risk (122,977 cases/105,974 controls in women) and the two subtypes: estrogen receptor (ER)-positive breast cancer and ER-negative breast cancer. Fixed and random effects inverse variance weighted methods were used to estimate the causal effects, along with other additional MR methods for sensitivity analyses. Results: Results showed that each additional standard deviation of 4.2 years of education was causally associated with a 27% lower risk of ER-negative breast cancer (odds ratio, 0.73; 95% confidence interval, 0.64–0.84; p-value < 0.001). This finding was consistent with the results of the sensitivity analyses. Physical activities can help improve the protective effect of education against breast cancer, with relatively large mediation proportions. Education increases the risk of ER-positive breast cancer due to alterations in high-density lipoprotein level, triglyceride level, height, waist-to-hip ratio, body mass index, and smoking status, with relative medium mediation proportions. Other mediators including low-density lipoprotein, hip circumference, number of cigarettes smoked per day, time spent performing light physical activity, and performing vigorous physical activity for > 10 minutes explain a small part of the causal effect of education on the risk of developing breast cancer, and their mediation proportion is approximately 1%. Conclusion: A low level of education is a causal risk factor in the development of breast cancer as it is associated with poor lipid profile, obesity, smoking, and types of physical activity.

THE FLAT EXTENSION OF NONSINGULAR EMBRY MOMENT MATRICES E(3)

Li, Chunji,Liang, Hongkai Korean Mathematical Society 2020 대한수학회논문집 Vol.35 No.1

Let γ⁽ⁿ⁾ ≡ {γ_ij} (0 ≤ i+j ≤ 2n, |i-j| ≤ n) be a sequence in the complex number set ℂ and let E (n) be the Embry truncated moment matrices corresponding from γ⁽ⁿ⁾. For an odd number n, it is known that γ⁽ⁿ⁾ has a rank E (n)-atomic representing measure if and only if E(n) ≥ 0 and E(n) admits a flat extension E(n + 1). In this paper we suggest a related problem: if E(n) is positive and nonsingular, does E(n) have a flat extension E(n + 1)? and give a negative answer in the case of E(3). And we obtain some necessary conditions for positive and nonsingular matrix E (3), and also its sufficient conditions.

Preparation of 2,3,4,5-Tetrafluorobenzoic Acid

Li, Hua,Wang, Hongkai,Zhao, Ruiju,Liu, Juan,Zhao, Zhengui,Hu, Guoqin,Liang, Zhengyong Korean Chemical Society 2010 대한화학회지 Vol.54 No.6

Fluoroquinolone 항생제의 중요한 중간체인 2,3,4,5-tetrafluorobenzoic acid를 tetrachloride phthalic anhydride에서 출발 하여 imidation, fluorination, hydrolysis과 decarboxylation단계를 거쳐서 합성하였다. Imdation 단계에서는 상전이 촉매를 이용하여 98.2%의 수율로 합성하였으며, fluorination 단계에서는 81.3%, 가수분해 단계에서는 88.6%, 마지막으로 decarboxylation단계에서는 81.6%의 수율로 합성하였다. 2,3,4,5-Tetrafluorobenzoic acid, an important intermediates of fluoroquinolone antibiotics, was synthesized from tetrachloride phthalic anhydride through imidation, fluorination, hydrolysis and decarboxylation. The effects of phase transfer catalyst on imidation and fluorination reaction and the effects of surfactants on the hydrolysis reaction were studied, respectively. Experimental results showed that the imidation reaction time was greatly reduced in the presence of a phase transfer catalyst, hexadecyltrimethyl, resulting in imidation yield as high as 98.2%. The fluorination yield reached 81.3% when tetrabutylammonium bromide was chosen as a phase transfer catalyst. The hydrolysis reaction time was also decreased by adding hexadecyltrimethyl while increasing the yield to 88.6%. In the post-processing, the sublimation method was used to purify the product, and ideal effect was obtained. In the decarboxylation reaction, tetrafluoride phthalic acid was obtained by decarboxylation in the solvent of tri-n-butyl amine and decarboxylation yield reached 81.6%. Compared with the literature method, the overall reaction time of the improved method decreased from 53 h to 20.5 h and the total yield increased from 47.3% to 57.4%.

Preparation of Novel Ionic Liquids and Their Applications in Brominating Reaction

Li, Hua,Liu, Juan,Zhu, Jiang,Wang, Hongkai Korean Chemical Society 2011 대한화학회지 Vol.55 No.4

새로운 산성 이온용액인1-(${\omega}$-sulfonicacid)propyl-3-methylimidazolium bromide ([$HSO_3$pmim]Br)과 1-(${\omega}$-sulfonicacid)-butyl-3-methylimidazolium bromide([$HSO_3$bmim]Br)을 제조하였다. 이 화합물들을 브롬화 시약 및 용매로 사용하여 $100^{\circ}C$, 2시간 반응시켰으며, 간단히 상분리에 의해 1,7-dibromoheptane을 95% 수율로 합성하였다. 이 산성 이온용액을 5회 재사용하였으나 수율 감소가 관찰되지 않았다. Novel acidic ionic liquids, 1-(${\omega}$-sulfonicacid)propyl-3-methylimidazolium bromide ([$HSO_3$pmim]Br)and 1-(${\omega}$-sulfonicacid)butyl-3-methylimidazolium bromide ([$HSO_3$bmim]Br), were prepared and used as brominating agents, catalysts and solvents in the synthesis of 1,7-dibromoheptane, respectively. 1,7-dibromoheptan with a yield of 95% was obtained at $100^{\circ}C$ for 2 h by simple phase separation. The acidic ionic liquid [$HSO_3$pmim]Br was recycled for 5 times and the yield of 1,7-dibromoheptane did not decrease remarkably, which indicates that catalysts still maintain good selectivity and activity after recycling. The structure of the acidic ionic liquid [$HSO_3$pmim]Br was characterized with IR, and it was found that [$HSO_3$pmim]Br had stronger acidity than other ionic liquid.

新时代背景下大学生素质教育发展性评价体系构建研究

邓宏凯(Hongkai Deng),吴东吹(Dongchui Wu),刘利(Li Liu) YIXIN 출판사 2023 教育教学研究论丛 Vol.1 No.5

本文围绕习近平总书记关于教育的重要论述和全国教育大会精神,立足“五育并举”,充分挖掘“三全育人”和“十大育人”体系要素,构建大学生素质教“六维一体”发展性评价体系。大学生发展性评价体系可以从德育、智育、体育、美育、劳育、能力六个维度对大学生的素质进行全面评估,使教育者、学生、家长和社会更加关注学生的全面发展,为提高大学生综合素质和培养创新型人才提供支持。其中德育的指标体系包括价值观、道德品质和心理素质三个指标;智育的评价通常是通过学生的学术成绩来进行;体育的指标体系包括身体形态指标、身体素质指标、运动技能指标和健康相关指标;美育包括审美理解、艺术技能、艺术创作和参与程度四个维度;劳育包括劳动态度、劳动技能、劳动习惯和社会责任感;大学生能力指标体系建构包括学术能力、实践能力和沟通与合作能力。 This article focuses on General Secretary Xi Jinping’s important exposition on education and the spirit of the National Education Conference, based on “simultaneous development of five educations”, fully exploring the elements of the “Three Complete Education” and “Ten Education” systems, and building a “six-dimensional integration” developmental evaluation system of quality education for college students. The development evaluation system of college students can comprehensively evaluate the quality of college students from six dimensions: moral education, intellectual education, physical education, aesthetic education, labor education, and ability. It enables educators, students, parents, and society to pay more attention to the all-round development of students, and provides a way to improve the comprehensive development of college students, providing support for improving quality and cultivating innovative talents. Among them, the indicator system of moral education includes three indicators: values, moral quality and psychological quality; the evaluation of intellectual education is usually carried out through students’ academic achievements; the indicator system of sports includes body shape indicators, physical quality indicators, sports skill indicators and health-related indicators; aesthetic education It includes four dimensions: aesthetic understanding, artistic skills, artistic creation and participation level; labor education includes labor attitude, labor skills, labor habits and social responsibility; the construction of college student ability index system includes academic ability, practical ability and communication and cooperation ability.