A new algorithm called homotopy iteration method based on the homotopy function is studied and improved. By the improved homotopy iteration method, Polynomial systems with high Order and deficient can be solved fast a...A new algorithm called homotopy iteration method based on the homotopy function is studied and improved. By the improved homotopy iteration method, Polynomial systems with high Order and deficient can be solved fast and efficiently comparing to the original homotopy iteration method. Numerical examples for the ninepoint path synthesis of four-bar linkages show the advantages and efficiency of the improved homotopy iteration method.展开更多
For a spherical four-bar linkage,the maximum number of the spherical RR dyad（R：revolute joint）of five-orientation motion generation can be at most 6.However,complete real solution of this problem has seldom been st...For a spherical four-bar linkage,the maximum number of the spherical RR dyad（R：revolute joint）of five-orientation motion generation can be at most 6.However,complete real solution of this problem has seldom been studied.In order to obtain six real RR dyads,based on Strum＇s theorem,the relationships between the design parameters are derived from a 6th-degree univariate polynomial equation that is deduced from the constraint equations of the spherical RR dyad by using Dixon resultant method.Moreover,the Grashof condition and the circuit defect condition are taken into account.Given the relationships between the design parameters and the aforementioned two conditions,two objective functions are constructed and optimized by the adaptive genetic algorithm（AGA）.Two examples with six real spherical RR dyads are obtained by optimization,and the results verify the feasibility of the proposed method.The paper provides a method to synthesize the complete real solution of the five-orientation motion generation,which is also applicable to the problem that deduces to a univariate polynomial equation and requires the generation of as many as real roots.展开更多
For the four-bar beating-up mechanism of air-jet loom,the plain bearing of linkage is the bearing with dynamic load,and is immersed in the lubricant-box.If the joint clearance is considered,the research on linkage mov...For the four-bar beating-up mechanism of air-jet loom,the plain bearing of linkage is the bearing with dynamic load,and is immersed in the lubricant-box.If the joint clearance is considered,the research on linkage movement could be very complicated.In this paper,the kinematic characteristics of four-bar beating-up mechanism with joint clearance were studied by analyzing the trace of journal center and the balance of radial,tangential forces,and bearing load.The region of principal vibration and its forming causes were discussed.And the results could interpret the measuring curves of four-bar beating-up mechanism completely.展开更多
In this work, we develop an artificial foldable wing that mimics the hind wing of a beetle （Allomyrina dichotoma）. In real flight, the beetle unfolds forewings and hind wings, and maintains the unfolded configuratio...In this work, we develop an artificial foldable wing that mimics the hind wing of a beetle （Allomyrina dichotoma）. In real flight, the beetle unfolds forewings and hind wings, and maintains the unfolded configuration unless it is exhausted. The artificial wing has to be able to maintain a fully unfolded configuration while flapping at a desirable flapping frequency. The artificial foldable hind wing developed in this work is based on two four-bar linkages which adapt the behaviors of the beetle＇s hind wing. The four-bar-linkages are designed to mimic rotational motion of the wing base and the vein folding/unfolding motion of the beetle＇s hind wing. The behavior of the artificial wings, which are installed in a flapping-wing system, is observed using a high-speed camera. The observation shows that the wing could maintain a fully unfolded configuration during flapping motion. A series of thrust measurements are also conducted to estimate the force generated by the flapping-wing system with foldable artificial wings. Although the artificial foldable wings give added burden to the flapping-wing system because of its weight, the thrust measurement results show that the flapping-wing system could still generate reasonable thrust.展开更多
Click chemistry has become a useful tool for diverse molecular linkage and modification, and the development of new click strategy that enable reversibility and multifunctionality is of high demand for the multifuncti...Click chemistry has become a useful tool for diverse molecular linkage and modification, and the development of new click strategy that enable reversibility and multifunctionality is of high demand for the multifunction and drug release. Herein, compositionally clicking combined regioselective iridium-catalyzed azide-alkynthio cycloaddition(Ir-AAC) and disulfuration has been developed for the sequential linkage from N-acetylenethio phthalimides, naturally occurring thiols and readily available azides. This method has been successfully applied to the construction of drug hybrids, peptide modification and glycosylation. Furthermore, by the design of diacetylenethio phthalimide as a platform molecule, trifunctional conjugants were sequentially linked through independent Ir-AAC, disulfuration and Cu-AAC reaction for hydrophobic tagging ternary PROTACs.展开更多
目的:筛查冠心病血瘀证病证结合相关基因。方法:区组选择符合诊断标准的冠心病血瘀证、冠心病非血瘀证、非冠心病血瘀证患者和正常健康者共40例,运用外周血mRNA差异显示获得差异条带、反向Northern法阳性验证、克隆测序,并进行生物信息...目的:筛查冠心病血瘀证病证结合相关基因。方法:区组选择符合诊断标准的冠心病血瘀证、冠心病非血瘀证、非冠心病血瘀证患者和正常健康者共40例,运用外周血mRNA差异显示获得差异条带、反向Northern法阳性验证、克隆测序,并进行生物信息学分析。结果:得到了28条真实差异基因片段序列,于NCBI human genomic数据库中比对分析,获得了与人类基因100％同源的3条(b13、49b、23b),99％同源的2条(b12、36a),98％同源(25b、57d)2条。其中的b13为淋巴细胞活化信号分子家族成员1,表达于T、B细胞表面,参与多系统的炎症反应,促进Th2类细胞因子的分泌,在冠心病血瘀证组呈高表达。23b系BCL2相关转录因子1,参与凋亡调控基因BCL2的转录过程,明显表达于冠心病血瘀证组。结论:差异基因中b13、23b从不同途径,导致或参与了脂代谢、血液高粘高聚高凝状态的形成,并通过分泌炎性细胞因子,调控细胞凋亡,参与了内皮损伤和动脉硬化的形成。与冠心痛血瘀证的病理改变密切相关。展开更多
Backfill hydraulic support is the key equipment in achieving coal mining and solid backfilling simultaneously in solid backfill mining technology.Based on the summary and analysis of main types,basic structural proper...Backfill hydraulic support is the key equipment in achieving coal mining and solid backfilling simultaneously in solid backfill mining technology.Based on the summary and analysis of main types,basic structural properties and filed application of backfill hydraulic support,this work has firstly proposed the basic principle of backfill hydraulic support optimization design and provided the method of optimal design of key structural components,like four-bar linkage,rear canopy and tamping structure;the method is further elaborated as changing hinging position of upper bar to optimize four-bar linkage,by lengthening or shortening the rear canopy to optimize length ratio of canopy;and by changing length and hinging position of tamping structure as well as suspension height of backfill scrape conveyor to realize optimization of tamping structure.On this basis,the process of optimal design of backfill hydraulic support is built.The optimal design case of ZC5200/14.5/30 six columns-four bar linkage used in 7203 W workface of Zhaizhen Coal Mine shows that the backfill properties like horizontal roof gap,vertical horizontal gap,tamping angle and tamping head gap are improved obviously through optimizing four-bar linkage,canopy length and tamping structure according to the optimal design method proposed in this work.展开更多
文摘A new algorithm called homotopy iteration method based on the homotopy function is studied and improved. By the improved homotopy iteration method, Polynomial systems with high Order and deficient can be solved fast and efficiently comparing to the original homotopy iteration method. Numerical examples for the ninepoint path synthesis of four-bar linkages show the advantages and efficiency of the improved homotopy iteration method.
基金Supported by National Natural Science Foundation of China(Grant Nos.51375059,61105103)National Hi-tech Research and Development Program of China(863 Program,Grant No.2011AA040203)Beijing Municipal Natural Science Foundation of China(Grant No.4132032)
文摘For a spherical four-bar linkage,the maximum number of the spherical RR dyad（R：revolute joint）of five-orientation motion generation can be at most 6.However,complete real solution of this problem has seldom been studied.In order to obtain six real RR dyads,based on Strum＇s theorem,the relationships between the design parameters are derived from a 6th-degree univariate polynomial equation that is deduced from the constraint equations of the spherical RR dyad by using Dixon resultant method.Moreover,the Grashof condition and the circuit defect condition are taken into account.Given the relationships between the design parameters and the aforementioned two conditions,two objective functions are constructed and optimized by the adaptive genetic algorithm（AGA）.Two examples with six real spherical RR dyads are obtained by optimization,and the results verify the feasibility of the proposed method.The paper provides a method to synthesize the complete real solution of the five-orientation motion generation,which is also applicable to the problem that deduces to a univariate polynomial equation and requires the generation of as many as real roots.
文摘For the four-bar beating-up mechanism of air-jet loom,the plain bearing of linkage is the bearing with dynamic load,and is immersed in the lubricant-box.If the joint clearance is considered,the research on linkage movement could be very complicated.In this paper,the kinematic characteristics of four-bar beating-up mechanism with joint clearance were studied by analyzing the trace of journal center and the balance of radial,tangential forces,and bearing load.The region of principal vibration and its forming causes were discussed.And the results could interpret the measuring curves of four-bar beating-up mechanism completely.
文摘In this work, we develop an artificial foldable wing that mimics the hind wing of a beetle （Allomyrina dichotoma）. In real flight, the beetle unfolds forewings and hind wings, and maintains the unfolded configuration unless it is exhausted. The artificial wing has to be able to maintain a fully unfolded configuration while flapping at a desirable flapping frequency. The artificial foldable hind wing developed in this work is based on two four-bar linkages which adapt the behaviors of the beetle＇s hind wing. The four-bar-linkages are designed to mimic rotational motion of the wing base and the vein folding/unfolding motion of the beetle＇s hind wing. The behavior of the artificial wings, which are installed in a flapping-wing system, is observed using a high-speed camera. The observation shows that the wing could maintain a fully unfolded configuration during flapping motion. A series of thrust measurements are also conducted to estimate the force generated by the flapping-wing system with foldable artificial wings. Although the artificial foldable wings give added burden to the flapping-wing system because of its weight, the thrust measurement results show that the flapping-wing system could still generate reasonable thrust.
基金supported by the National Natural Science Foundation of China (Nos. 21901179 and 22125103)the Scientific Activities of Selected Returned Overseas Professionals of Shanxi Province (No. 20200002)+1 种基金the Natural Science Foundation of Shanxi Province (No. 202103021224067)the Research Project of Shanxi Scholarship Council (No. HGKY2019029)。
文摘Click chemistry has become a useful tool for diverse molecular linkage and modification, and the development of new click strategy that enable reversibility and multifunctionality is of high demand for the multifunction and drug release. Herein, compositionally clicking combined regioselective iridium-catalyzed azide-alkynthio cycloaddition(Ir-AAC) and disulfuration has been developed for the sequential linkage from N-acetylenethio phthalimides, naturally occurring thiols and readily available azides. This method has been successfully applied to the construction of drug hybrids, peptide modification and glycosylation. Furthermore, by the design of diacetylenethio phthalimide as a platform molecule, trifunctional conjugants were sequentially linked through independent Ir-AAC, disulfuration and Cu-AAC reaction for hydrophobic tagging ternary PROTACs.
文摘目的:筛查冠心病血瘀证病证结合相关基因。方法:区组选择符合诊断标准的冠心病血瘀证、冠心病非血瘀证、非冠心病血瘀证患者和正常健康者共40例,运用外周血mRNA差异显示获得差异条带、反向Northern法阳性验证、克隆测序,并进行生物信息学分析。结果:得到了28条真实差异基因片段序列,于NCBI human genomic数据库中比对分析,获得了与人类基因100％同源的3条(b13、49b、23b),99％同源的2条(b12、36a),98％同源(25b、57d)2条。其中的b13为淋巴细胞活化信号分子家族成员1,表达于T、B细胞表面,参与多系统的炎症反应,促进Th2类细胞因子的分泌,在冠心病血瘀证组呈高表达。23b系BCL2相关转录因子1,参与凋亡调控基因BCL2的转录过程,明显表达于冠心病血瘀证组。结论:差异基因中b13、23b从不同途径,导致或参与了脂代谢、血液高粘高聚高凝状态的形成,并通过分泌炎性细胞因子,调控细胞凋亡,参与了内皮损伤和动脉硬化的形成。与冠心痛血瘀证的病理改变密切相关。
基金Project(2017QNA21)supported by the Fundamental Research Funds for the Central Universities of ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),China
文摘Backfill hydraulic support is the key equipment in achieving coal mining and solid backfilling simultaneously in solid backfill mining technology.Based on the summary and analysis of main types,basic structural properties and filed application of backfill hydraulic support,this work has firstly proposed the basic principle of backfill hydraulic support optimization design and provided the method of optimal design of key structural components,like four-bar linkage,rear canopy and tamping structure;the method is further elaborated as changing hinging position of upper bar to optimize four-bar linkage,by lengthening or shortening the rear canopy to optimize length ratio of canopy;and by changing length and hinging position of tamping structure as well as suspension height of backfill scrape conveyor to realize optimization of tamping structure.On this basis,the process of optimal design of backfill hydraulic support is built.The optimal design case of ZC5200/14.5/30 six columns-four bar linkage used in 7203 W workface of Zhaizhen Coal Mine shows that the backfill properties like horizontal roof gap,vertical horizontal gap,tamping angle and tamping head gap are improved obviously through optimizing four-bar linkage,canopy length and tamping structure according to the optimal design method proposed in this work.
