Self-discharge is a significant issue in electric double layer energy storage, which leads to a rapid voltage drop and low energy efficiency. Here, we attempt to solve this problem by changing the structure of the ele...Self-discharge is a significant issue in electric double layer energy storage, which leads to a rapid voltage drop and low energy efficiency. Here, we attempt to solve this problem by changing the structure of the electric double layer into a de-solvated state, by constructing a nano-scale and ion-conductive solid electrolyte layer on the surface of a carbon electrode. The ion concentration gradient and potential field that drive the self-discharge are greatly restricted inside this electric double layer. Based on this understanding, a high-efficiency graphene-based lithium ion capacitor was built up, in which the self-discharge rate is reduced by 50% and the energy efficiency is doubled. The capacitor also has a high energy density, high power output and long life, and shows promise for practical applications.展开更多
The harvesting of fresh kiwifruit is a labor-intensive operation that accounts for more than 25%of annual production costs.Mechanized harvesting technologies are thus being developed to reduce labor requirements for h...The harvesting of fresh kiwifruit is a labor-intensive operation that accounts for more than 25%of annual production costs.Mechanized harvesting technologies are thus being developed to reduce labor requirements for harvesting kiwifruit.To improve the efficiency of a harvesting robot for picking kiwifruit,we designed an end-effector,which we report herein along with the results of tests to verify its operation.By using the established method of automated picking discussed in the literature and which is based on the characteristics of kiwifruit,we propose an automated method to pick kiwifruit that consists of separating the fruit from its stem on the tree.This method is experimentally verified by using it to pick clustered kiwifruit in a scaffolding canopy cultivation.In the experiment,the end-effector approaches a fruit from below and then envelops and grabs it with two bionic fingers.The fingers are then bent to separate the fruit from its stem.The grabbing,picking,and unloading processes are integrated,with automated picking and unloading performed using a connecting rod linkage following a trajectory model.The trajectory was analyzed and validated by using a simulation implemented in the software Automatic Dynamic Analysis of Mechanical Systems(ADAMS).In addition,a prototype of an end-effector was constructed,and its bionic fingers were equipped with fiber sensors to detect the best position for grabbing the kiwifruit and pressure sensors to ensure that the damage threshold was respected while picking.Tolerances for size and shape were incorporated by following a trajectory groove from grabbing and picking to unloading.The end-effector separates clustered kiwifruit and automatically grabs individual fruits.It takes on average 4–5 s to pick a single fruit,with a successful picking rate of 94.2%in an orchard test featuring 240 samples.This study shows the grabbing–picking–unloading robotic end-effector has significant potential to facilitate the harvesting of kiwifruit.展开更多
By means of a transfer matrix method, this paper deduces the transmittance calculation equation of light travelling in locally doped （including one defect layer） mirror heterostructure （ABCCBA）PD（ABCCBA）q photon...By means of a transfer matrix method, this paper deduces the transmittance calculation equation of light travelling in locally doped （including one defect layer） mirror heterostructure （ABCCBA）PD（ABCCBA）q photonic crystals. In the cases of defect layers being either introduced or not introduced, an ORIGIN simulation shows the influence of incident angle change on the number of photon band gap, bandwidth and defect mode numbers. Studies indicate that when such photonic crystals have 8 mirror cycles and the thickness of defect layer D meets nDdD = X0/2 or nodD = 4）~0, the photonic crystal defect mode transmission peak changes significantly. Also, with the change of incident angle, the number of defect mode transmission peaks changes. By altering incident angle and defect layer thickness, we can get photon band gaps and defect mode transmission peaks at different frequency domains and different relative angular frequencies. This provides theoretical reference for achieving light wave multi-channel filtering and tunable filtering.展开更多
The intramolecular electronic communication and multilevel ion-pairing effect of triferrocenylmethane（TriFcM） in organic phase was studied with the ＂thin-layer electrochemistry＂ approach.Three pairs of symmetric p...The intramolecular electronic communication and multilevel ion-pairing effect of triferrocenylmethane（TriFcM） in organic phase was studied with the ＂thin-layer electrochemistry＂ approach.Three pairs of symmetric peaks in cyclic voltammetry of TriFcM correspond to three one-electron electrochemical reaction processes and indicate strong intramolecular electronic communication,which could be used to study the multilevel ion-pairing effect.Three different formation constants of ion-pairs between the three ferroceniums of TriFcM and perchlorate in thin organic film were obtained and compared.展开更多
基金supported by the National Natural Science Foun-dation of China (Nos. 51525206 , 51521091 and 51172239)the Ministry of Science and Technology of China(2016YFA0200100 ,2016YFB0100100)+4 种基金the Strategic Priority Research Program of Chinese Academy of Science (XDA22010602)the Key Research Program of Chinese Academy of Sciences (Grant No. KGZD-EWT06)the Program for Guangdong Introducing Innovative and Enterpreneurial Teamsthe Strategic Priority Research Program of Chinese Academy of Science (No. XDA22010602)the Development and Reform Commission of Shenzhen Municipality for the development of the “Low-Dimensional Materials and Devices” discipline
文摘Self-discharge is a significant issue in electric double layer energy storage, which leads to a rapid voltage drop and low energy efficiency. Here, we attempt to solve this problem by changing the structure of the electric double layer into a de-solvated state, by constructing a nano-scale and ion-conductive solid electrolyte layer on the surface of a carbon electrode. The ion concentration gradient and potential field that drive the self-discharge are greatly restricted inside this electric double layer. Based on this understanding, a high-efficiency graphene-based lithium ion capacitor was built up, in which the self-discharge rate is reduced by 50% and the energy efficiency is doubled. The capacitor also has a high energy density, high power output and long life, and shows promise for practical applications.
基金This research was conducted in the College of Mechanical and Electronic Engineering,Northwest A&F University,and was supported by research grants from the General Program of the National Natural Science Foundation of China(61175099).
文摘The harvesting of fresh kiwifruit is a labor-intensive operation that accounts for more than 25%of annual production costs.Mechanized harvesting technologies are thus being developed to reduce labor requirements for harvesting kiwifruit.To improve the efficiency of a harvesting robot for picking kiwifruit,we designed an end-effector,which we report herein along with the results of tests to verify its operation.By using the established method of automated picking discussed in the literature and which is based on the characteristics of kiwifruit,we propose an automated method to pick kiwifruit that consists of separating the fruit from its stem on the tree.This method is experimentally verified by using it to pick clustered kiwifruit in a scaffolding canopy cultivation.In the experiment,the end-effector approaches a fruit from below and then envelops and grabs it with two bionic fingers.The fingers are then bent to separate the fruit from its stem.The grabbing,picking,and unloading processes are integrated,with automated picking and unloading performed using a connecting rod linkage following a trajectory model.The trajectory was analyzed and validated by using a simulation implemented in the software Automatic Dynamic Analysis of Mechanical Systems(ADAMS).In addition,a prototype of an end-effector was constructed,and its bionic fingers were equipped with fiber sensors to detect the best position for grabbing the kiwifruit and pressure sensors to ensure that the damage threshold was respected while picking.Tolerances for size and shape were incorporated by following a trajectory groove from grabbing and picking to unloading.The end-effector separates clustered kiwifruit and automatically grabs individual fruits.It takes on average 4–5 s to pick a single fruit,with a successful picking rate of 94.2%in an orchard test featuring 240 samples.This study shows the grabbing–picking–unloading robotic end-effector has significant potential to facilitate the harvesting of kiwifruit.
基金supported by the National Natural Science Foundation of China(Nos.60776062,50730009)
文摘By means of a transfer matrix method, this paper deduces the transmittance calculation equation of light travelling in locally doped （including one defect layer） mirror heterostructure （ABCCBA）PD（ABCCBA）q photonic crystals. In the cases of defect layers being either introduced or not introduced, an ORIGIN simulation shows the influence of incident angle change on the number of photon band gap, bandwidth and defect mode numbers. Studies indicate that when such photonic crystals have 8 mirror cycles and the thickness of defect layer D meets nDdD = X0/2 or nodD = 4）~0, the photonic crystal defect mode transmission peak changes significantly. Also, with the change of incident angle, the number of defect mode transmission peaks changes. By altering incident angle and defect layer thickness, we can get photon band gaps and defect mode transmission peaks at different frequency domains and different relative angular frequencies. This provides theoretical reference for achieving light wave multi-channel filtering and tunable filtering.
基金the NSFC(No.21173023)the 111 Project(No.B07012) in China and the TriFcM provided from professor Hua-Zhong Yu at Simon Fraser University in Canada
文摘The intramolecular electronic communication and multilevel ion-pairing effect of triferrocenylmethane（TriFcM） in organic phase was studied with the ＂thin-layer electrochemistry＂ approach.Three pairs of symmetric peaks in cyclic voltammetry of TriFcM correspond to three one-electron electrochemical reaction processes and indicate strong intramolecular electronic communication,which could be used to study the multilevel ion-pairing effect.Three different formation constants of ion-pairs between the three ferroceniums of TriFcM and perchlorate in thin organic film were obtained and compared.
