Soil pore identification with the adaptive fuzzy C-means method based on computed tomography images

The complex geometry and topology of soil is widely recognised as the key driver in many ecological processes. X-ray computed tomography (CT) provides insight into the internal structure of soil pores automatically and accurately. Until recently, there have not been methods to identify soil pore structures. This has restricted the development of soil science, particularly regarding pore geometry and spatial distribution. Through the adoption of the fuzzy clustering theory and the establishment of pore identification rules, a novel pore identification method is described to extract pore structures from CT soil images. The robustness of the adaptive fuzzy C-means method (AFCM), the adaptive threshold method, and Image-Pro Plus tools were compared on soil specimens under different conditions, such as frozen, saturated, and dry situations. The results demonstrate that the AFCM method is suitable for identifying pore clusters, especially tiny pores, under various soil conditions. The method would provide an optional technique for the study of soil micromorphology.

Dynamics analysis on transverse cutting mechanism of straw checkerboard paving robot

The transverse cutting mechanism of the checkerboard paving robot, which directly affects the robot＇s operation, is regarded as the most important part in a transverse pavement system This research aims at designing a new system which is appropriate for desert wofidng en- vironments and finishing cutting the rope of straw. In this paper, computer emulating technology is applied, and with three-dimensional modeling by Pro/ENGINEER software, can observe whether or not interference exists. Also, the speed and displacement parameters of the main parts of the cutting system are given by the dynamic emulation by Automatic Dynamic Analysis of Mechanical System （ADAMS）, which theoretically assures the feasibility and appropriateness of the cutting mechanisrn~ Finally, results of the experinaent shows that the cutting mechanism can cut the straw strand as designed.

Resveratrol and Sir2 Reverse Sleep and Memory Defects Induced by Amyloid Precursor Protein

Resveratrol(RES),a natural polyphenolic phytochemical,has been suggested as a putative anti-aging molecule for the prevention and treatment of Alzheimer’s disease(AD)by the activation of sirtuin 1(Sirt1/Sir2).In this study,we tested the effects of RES and Sirt1/Sir2 on sleep and courtship memory in a Drosophila model by overexpression of amyloid precursor protein(APP),whose duplications and mutations cause familial AD.We found a mild but significant transcriptional increase of Drosophila Sir2(dSir2)by RES supplementation for up to 17 days in APP flies,but not for 7 days.RES and dSir2 almost completely reversed the sleep and memory deficits in APP flies.We further demonstrated that dSir2 acts as a sleep promotor in Drosophila neurons.Interestingly,RES increased sleep in the absence of dSir2 in dSir2-null mutants,and RES further enhanced sleep when dSir2 was either overexpressed or knocked down in APP flies.Finally,we showed that Aβaggregates in APP flies were reduced by RES and dSir2,probably via inhibiting Drosophilaβ-secretase(dBACE).Our data suggest that RES rescues the APP-induced behavioral deficits and Aβburden largely,but not exclusively,via dSir2.

基于动态光散射技术研究群体自驱动Janus颗粒的增强型布朗运动行为

自驱动Janus颗粒是两侧具有不同性质并可进行自驱运动的非均质颗粒的统称.本文以标称直径为1μm的Pt-SiO_2型自驱动Janus颗粒(以下简称Janus颗粒)为研究对象,利用动态光散射技术(dynamic light scattering, DLS)研究了其在纯水及不同浓度H2O2溶液中的运动行为.实验结果表明:群体Janus颗粒在H2O2溶液中的运动行为表现为增强型布朗运动.随着H_2O_2溶液浓度的增加,DLS测得群体Janus颗粒的有效扩散系数增大且都大于其在纯水中布朗运动时的扩散系数,且其弛豫时间逐渐减小.此外,根据DLS测得的自相关函数反演算推导得到了群体Janus颗粒在极短时间间隔内的均方位移.其结果表明:在相同观测时间间隔下,随着H_2O_2溶液浓度的增大,均方位移增加;在相同浓度的H_2O_2溶液中,随着观测时间间隔的增加,均方位移增加.最后,分析了单粒子追踪技术(single particle tracking,SPT)与DLS两种方法用于研究Janus颗粒运动行为的特点与区别,并指出观测时间间隔是影响DLS和SPT两种方法实验结果的关键因素.

Carbon performance evaluation model from the perspective of circular economy~The case of Chinese thermal power enterprise

Carbon emission reduction is the only way to alleviate environmental problems,such as global warming.Effective evaluation of carbon performance can help enterprises to carry out energy saving and emission reduction activities to a certain extent and promote sustainable development.This paper constructs a carbon performance evaluation index system that includes the four dimensions of carbon resource(energy)input,cycle,output,and carbon management by incorporating the principles of circular economy and the theory of resource value circulation from the perspective of the flow trajectory of carbon-containing resources in the circulation of enterprises combined with the production characteristics of thermoelectric enterprises.Subsequently,combined with the case study,this paper discusses the scientific and practical nature of the system and provides another way of thinking for carbon performance evaluation of micro-enterprises in other industries.This paper expands the application boundary of matter-element model and supplements the literature of carbon performance,which has certain theoretical and practical significance.

A person-following method based on monocular camera for quadruped robots

This paper proposes a person-following method based on monocular vision,which allows quadruped robots to track a target person in both indoor and outdoor environments with different illumination conditions.Our method is composed of a person detector,a Kalman filter(KF)tracker,and a re-identification module.To be more specific,the person detector uses a human pose estimation method to detect persons.The KF is applied to predict the position of the target person and update its state with detection results.A re-identification module is proposed to deal with distractions,where the Convolutional Channel Features(CCF)is used to extract appearance features and Online Boosting is used to distinguish the target person from others.Especially,we design a target recapture mechanism based on the Recurrent Neural Network(RNN).Combining motion information with appearance features,the system can accurately re-identify the target person.Without extra customized markers,our method can track the target person steadily in real-time only using a monocular camera.Experiments results can validate the robustness and effectiveness of the proposed method.