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95篇 您的检索式:作者名="Li Qifeng"
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1Adaptive optimization methodology based on Kriging modeling and a trust region method显示文摘Surrogate-Based Optimization(SBO) is becoming increasingly popular since it can remarkably reduce the computational cost for design optimizations based on high-fidelity and expensive numerical analyses. However, for complicated optimization problems with a large design space, many design variables, and strong nonlinearity, SBO converges slowly and shows imperfection in local exploitation. This paper proposes a trust region method within the framework of an SBO process based on the Kriging model. In each refinement cycle, new samples are selected by a certain design of experiment method within a variable design space, which is sequentially updated by the trust region method. A multi-dimensional trust-region radius is proposed to improve the adaptability of the developed methodology. Further, the scale factor and the limit factor of the trust region are studied to evaluate their effects on the optimization process. Thereafter, different SBO methods using error-based exploration, prediction-based exploitation, refinement based on the expected improvement function, a hybrid refinement strategy, and the developed trust-regionbased refinement are utilized in four analytical tests. Further, the developed optimization methodology is employed in the drag minimization of an RAE2822 airfoil. Results indicate that it has better robustness and local exploitation capability in comparison with those of other SBOChunna LI Qifeng PAN 2019Chinese Journal of Aeronautics2019,32,2:13
2Hes1 Knockdown Exacerbates Ischemic Stroke Following tMCAO by Increasing ER Stress-Dependent Apoptosis via the PERK/ eIF2a/ATF4/CHOP Signaling Pathway显示文摘Apoptosis induced by endoplasmic reticulum(ER)stress plays a crucial role in mediating brain damage after ischemic stroke.Recently,Hes1(hairy and enhancer of split 1)has been implicated in the regulation of ER stress,but whether it plays a functional role after ischemic stroke and the underlying mechanism remain unclear.In this study,using a mouse model of ischemic stroke via transient middle cerebral artery occlusion(tMCAO),we found that Hes1 was induced following brain injury,and that siRNA-mediated knockdown of Hes1 increased the cerebral infarction and worsened the neurological outcome,suggesting that Hes1 knockdown exacerbates ischemic stroke.In addition,mechanistically,Hes1 knockdown promoted apoptosis and activated the PERK/eIF2a/ATF4/CHOP signaling pathway after tMCAO.These results suggest that Hes1 knockdown promotes ER stress-induced apoptosis.Furthermore,inhibition of PERK with the specific inhibitor GSK2606414 markedly attenuated the Hes1 knockdown-induced apoptosis and the increased cerebral infarction as well as the worsened neurological outcome following tMCAO,implying that the protection of Hes1 against ischemic stroke is associated with the amelioration of ER stress via modulating the PERK/eIF2a/ATF4/CHOP signaling pathway.Taken together,these results unveil the detrimental role of Hes1 knockdown after ischemic stroke and further relate it to the regulation of ER stress-induced apoptosis,thus highlighting the importance of targeting ER stress in the treatment of ischemic stroke.Yueyong Li Yingjun Zhang Huangde Fu Huadong Huang Qifeng Lu Houji Qin Yingning Wu Huatuo Huang Guizhen Mao Zhongheng Wei Pinhu Liao 2020Neuroscience Bulletin2020,36,2:12
3Mild hypothermia combined with neural stem cell transplantation for hypoxic-ischemic encephalopathy: neuroprotective effects of combined therapy显示文摘Neural stem cell transplantation is a useful treatment for ischemic stroke, but apoptosis often occurs in the hypoxic-ischemic environment of the brain after cell transplantation. In this study, we determined if mild hypothermia(27–28°C) can increase the survival rate of neural stem cells(1.0 × 105 /μL) transplanted into neonatal mice with hypoxic-ischemic encephalopathy. Long-term effects on neurological functioning of the mice were also examined. After mild hypothermia combined with neural stem cell transplantation, we observed decreased expression levels of inflammatory factor nuclear factor-kappa B and apoptotic factor caspase-3, reduced cerebral infarct volumes, increased survival rate of transplanted cells, and marked improvements in neurological function. Thus, the neuroprotective effects of mild hypothermia combined with neural stem cell transplantation are superior to those of monotherapy. Moreover, our findings suggest that the neuroprotective effects of mild hypothermia combined with neural stem cell transplantation on hypoxic-ischemic encephalopathy are achieved by anti-inflammatory and anti-apoptotic mechanisms.Lin Wang Feng Jiang Qifeng Li Xiaoguang He Jie Ma 2014Neural Regeneration Research2014,9,19:12
4Monocular trajectory intersection method for 3D motion measurement of a point target显示文摘This article proposes a monocular trajectory intersection method,a videometrics measurement with a mature theoretical system to solve the 3D motion parameters of a point target.It determines the target’s motion parameters including its 3D trajectory and velocity by intersecting the parametric trajectory of a motion target and series of sight-rays by which a motion camera observes the target,in contrast with the regular intersection method for 3D measurement by which the sight-rays intersect at one point.The method offers an approach to overcome the technical failure of traditional monocular measurements for the 3D motion of a point target and thus extends the application fields of photogrammetry and computer vision.Wide application is expected in passive observations of motion targets on various mobile beds.YU QiFeng SHANG Yang ZHOU Jian ZHANG XiaoHu LI LiChun 2009Science China(Technological Sciences)2009,52,12:10
5Stepwise-Nanocavity-Assisted Transmissive Color Filter Array Microprints显示文摘Visible-light color flters using patterned nanostructures have attracted much interest due to their various advantages such as compactness,enhanced stability,and environmental friendliness compared with traditional pigment or dye-based optical flters.While most existing studies are based on planar nanostructures with lateral variation in size,shape,and arrangement,the vertical dimension of structures is a long-ignored degree of freedom for the structural colors.Herein,we demonstrate a synthetic platform for transmissive color flter array by coordinated manipulations between height-varying nanocavities and their lateral flling fractions.Te thickness variation of those nanocavities has been fully deployed as an alternative degree of freedom,yielding vivid colors with wide gamut and excellent saturation.Experimental results show that the color-rendering capability of the pixelated nanocavities can be still retained as pixels are miniaturized to 500 nm.Crosstalk between closely spaced pixels of a Bayer color flter arrangement was calculated,showing minimal crosstalk for 1μm2 square subpixels.Our work provides an approach to designing and fabricating ultracompact color flter arrays for various potential applications including stained-glass microprints,microspectrometers,and high-resolution image sensing systems.Yasi Wang Mengjie Zheng Qifeng Ruan Yanming Zhou Yiqin Chen Peng Dai Zhengmei Yang Zihao Lin Yuxiang Long Ying Li Na Liu Cheng-Wei Qiu Joel K.W.Yang Huigao Duan 2018Research2018,,1:8
6Research on 3D Target Pose Tracking and Modeling显示文摘This paper tackles pose tracking and model refinement, one of the fundamental work for 3D photogrammetry. The researches belong to the videometrics, an interdisciplinewhich combines computer vision, digital image processing, photogrammetry and optical measurement. Related works are summarized briefly in this paper. This paper studies the problem of pose tracking for target with 3D model. For the target with accurate 3D model, line model based pose tracking methods are proposed for target which is rich in line features. Experimental results indicate that the proposed methods track the target pose accurately. Normal distance iterative reweighted least squares and distance image iterative least squares methods are proposed to process more general targets. This paper adopts bundle adjustment to tackle pose tracking in image sequence for target with inaccurate 3D line model. The proposed method optimizes the model line parameters and the pose parameters simultaneously. The model line orientation, position and mean angle error, mean position error of the pose are 0.3°,3.5 mm and 0.12°,20.1 mm in simulation experiments of satellite pose tracking. Line features are used to track target pose with unknown 3D model through image sequence. The model line parameters and pose parameters are optimized under the framework of SFM. In simulation experiments, the reconstructed line orientation, position error and mean angle error, mean position error of pose are 0.4°,7.5 mm and 0.16°,23.5 mm.Yang SHANG Xiaoliang SUN Yueqiang ZHANG You LI Qifeng YU 2019Journal of Geodesy and Geoinformation Science2019,2,2:7
7World’s first spaceflight on-orbit demonstration of a flexible solar array system based on shape memory polymer composites显示文摘With a 10%reversible compressive strain in more than 10 deformation cycles,the shape memory polymer composites(SMPCs)could be used for deployable structure and releasing mechanism.In this paper,without traditional electro-explosive devices or motors/controllers,the deployable SMPC flexible solar array system(SMPC-FSAS)is studied,developed,ground-based tested,and finally on-orbit validated.The epoxy-based SMPC is used for the rolling-out variable-stiffness beams as a structural frame as well as an actuator for the flexible blanket solar array.The releasing mechanism is primarily made of the cyanate-based SMPC,which has a high locking stiffness to withstand 50 g gravitational acceleration and a large unlocking displacement of 10 mm.The systematical mechanical and thermal qualification tests of the SMPC-FSAS flight hardware were performed,including sinusoidal sweeping vibration,shocking,acceleration,thermal equilibrium,thermal vacuum cycling,and thermal cycling test.The locking function of the SMPC releasing mechanisms was in normal when launching aboard the SJ20 Geostationary Satellite on 27 Dec.,2019.The SMPC-FSAS flight hardware successfully unlocked and deployed on 5 Jan.,2020 on geostationary orbit.The triggering signal of limit switches returned to ground at the 139 s upon heating,which indicated the successful unlocking function of SMPC releasing mechanisms.A pair of epoxy-based SMPC rolled variable-stiffness tubes,which clapped the flexible blanket solar array,slowly deployed and finally approached an approximate 100%shape recovery ratio within 60 s upon heating.The study and on-orbit successful validation of the SMPC-FSAS flight hardware could accelerate the related study and associated productions to be used for the next-generation releasing mechanisms as well as space deployable structures,such as new releasing mechanisms with low-shocking,testability and reusability,and ultra-large space deployable solar arrays.LAN Xin LIU LiWu ZHANG FengHua LIU ZhengXian WANG LinLin LI QiFeng PENG Fan HAO SiDa DAI WenXu WAN Xue TANG Yong WANG Mian HAO YanYan YANG Yang YANG Cheng LIU YanJu LENG JinSong 2020Science China(Technological Sciences)2020,63,8:7
8Recent Advances in Space-Deployable Structures in China显示文摘Deployable space structure technology is an approach used in building spacecraft,especially when realizing deployment and folding functions.Once in orbit,the structures are released from the fairing,deployed,and positioned.With the development of communication,remote-sensing,and navigation satellites,space-deployable structures have become cutting-edge research topics in space science and technology.This paper summarizes the current research status and development trend of spacedeployable structures in China,including large space mesh antennas,space solar arrays,and deployable structures and mechanisms for deep-space exploration.Critical technologies of space-deployable structures are addressed from the perspectives of deployable mechanisms,cable-membrane form-finding,dynamic analysis,reliable environmental adaptability analysis,and validation.Finally,future technology developments and trends are elucidated in the fields of mesh antennas,solar arrays,deployable mechanisms,and on-orbit adjustment,assembly,and construction.Xiaofei Ma Tuanjie Li Jingya Ma Zhiyi Wang Chuang Shi Shikun Zheng Qifeng Cui Xiao Li Fan Liu Hongwei Guo Liwu Liu Zuowei Wang Yang Li 2022Engineering2022,,10:6
9Sandwich structured graphene-wrapped FeS-graphene nanoribbons with improved cycling stability for lithium ion batteries显示文摘三明治组织了包 graphene 的 FeS-graphene nanoribbons (G@FeS-GNRs ) 被开发。在这合成, FeS nanoparticles 在 graphene 和 graphene nanoribbons 之间被夹。当在锂离子电池(解放) 用作阳极时, G@FeS-GNR 合成表明了突出的电气化学的表演。这个合成显示出的高可逆的能力,好率表演,和由于在电子上传导性的 graphene, graphene nanoribbons,和 FeS 之间的协同作用的提高的骑车的稳定性。这里开发的设计概念为为解放与改进电气化学的稳定性构造阳极开创一条新大街。Lei Li Caitian Gao Anton Kovalchuk Zhiwei Peng Gedeng Ruan Yang Yang Huilong Fei Qifeng Zhong Yilun Li James M. Tour 2016Nano Research2016,9,10:5
10A method for weighing broiler chickens using improved amplitude-limiting filtering algorithm and BP neural networks显示文摘Broiler chickens are traditionally weighed by steelyard or platform scale,which is timeconsuming and labor-intensive.Broiler chickens usually exhibit stress-related behavior during weighing.The 3D camera-based weighing system for broiler chickens can only weigh the broiler chicken in the monitoring area.Usually,it makes poor weight prediction due to poor segmentation especially when the broiler chicken is flapping its wings.To solve these issues,we developed one simple and low-cost weighing system with high stability and accuracy.A validity value extraction method from dynamic weighing was proposed.Then,an improved amplitude-limiting filtering algorithm and a BP neural networks model were developed to avoid accidental interference.The BP neural networks model used daily weight gain,day-age,average velocity,and the weight data after filtering algorithm as the input layer.The weighing system was tested in a commercial Beijing Fatty Chickens house with Beijing Fatty Chickens.We tested thirteen groups of Beijing Fatty Chickens of different weights,from 500 g to 1800 g in intervals of 100 g,using the three different methods:no filtering algorithm or BP neural networks,only the improved amplitude-limiting filtering algorithm and a hybrid of the improved amplitude-limiting filtering algorithm and BP neural networks.The results showed that the hybrid algorithm had a better performance in minimizing the error,lowering from the original 6%down to 3%.The accurate weight data was transmitted to the remote service platform for further decision-making,such as activity analysis,feeding management,and health alerts.Weihong Ma Qifeng Li Jiawei Li Luyu Ding Qinyang Yu 2021Information Processing in Agriculture2021,8,2:5
11Highly Selective Biomimetic Flexible Tactile Sensor for Neuroprosthetics显示文摘Biomimetic flexible tactile sensors endow prosthetics with the ability to manipulate objects,similar to human hands.However,it is still a great challenge to selectively respond to static and sliding friction forces,which is crucial tactile information relevant to the perception of weight and slippage during grasps.Here,inspired by the structure of fingerprints and the selective response of Ruffini endings to friction forces,we developed a biomimetic flexible capacitive sensor to selectively detect static and sliding friction forces.The sensor is designed as a novel plane-parallel capacitor,in which silver nanowire-3D polydimethylsiloxane(PDMS)electrodes are placed in a spiral configuration and set perpendicular to the substrate.Silver nanowires are uniformly distributed on the surfaces of 3D polydimethylsiloxane microcolumns,and silicon rubber(Ecoflex^(■))acts as the dielectric material.The capacitance of the sensor remains nearly constant under different applied normal forces but increases with the static friction force and decreases when sliding occurs.Furthermore,aiming at the slippage perception of neuroprosthetics,a custom-designed signal encoding circuit was designed to transform the capacitance signal into a bionic pulsed signal modulated by the applied sliding friction force.Test results demonstrate the great potential of the novel biomimetic flexible sensors with directional and dynamic sensitivity of haptic force for smart neuroprosthetics.Yue Li Zhiguang Cao Tie Li Fuqin Sun Yuanyuan Bai Qifeng Lu Shuqi Wang Xianqing Yang Manzhao Hao Ning Lan Ting Zhang 2020Research2020,,1:4
12Serum semaphorin 4C as a diagnostic biomarker in breast cancer:A multicenter retrospective study显示文摘Background:To date,there is no approved blood-based biomarker for breast cancer detection.Herein,we aimed to assess semaphorin 4C(SEMA4C),a pivotal protein involved in breast cancer progression,as a serum diagnostic biomarker.Methods:We included 6,213 consecutive inpatients from Tongji Hospital,Qilu Hospital,and Hubei Cancer Hospital.Training cohort and two validation cohorts were introduced for diagnostic exploration and validation.A pan-cancer cohort was used to independently explore the diagnostic potential of SEMA4C among solid tumors.Breast cancer patients who underwent mass excision prior to modified radical mastectomy were also analyzed.We hypothesized that increased pretreatment serum SEMA4C levels,measured using optimized in-house enzymelinked immunosorbent assay kits,could detect breast cancer.The endpoints were diagnostic performance,including area under the receiver operating characteristic curve(AUC),sensitivity,and specificity.Post-surgery pathological diagnosis was the reference standard and breast cancer staging followed the TNM classification.There was no restriction on disease stage for eligibilities.Results:We included 2667 inpatients with breast lesions,2378 patients with other solid tumors,and 1168 healthy participants.Specifically,118 patients with breast cancer were diagnosed with stage 0(5.71%),620 with stage I(30.00%),966 with stage II(46.73%),217 with stage III(10.50%),and 8 with stage IV(0.39%).Patients with breast cancer had significantly higher serum SEMA4C levels than benign breast tumor patients and normal controls(P<0.001).Elevated serum SEMA4C levels had AUC of 0.920(95%confidence interval[CI]:0.900–0.941)and 0.932(95%CI:0.911–0.953)for breast cancer detection in the two validation cohorts.The AUCs for detecting early-stage breast cancer(n=366)and ductal carcinoma in situ(n=85)were 0.931(95%CI:0.916–0.946)and 0.879(95%CI:0.832–0.925),respectively.Serum SEMA4C levels significantly decreased after surgery,and the reduction was more striking after modified radical mastectomy,compared with mass excision(P<0.001).The positive rate of enhanced serum SEMA4C levels was 84.77%for breast cancer and below 20.75%for the other 14 solid tumors.Conclusions:Serum SEMA4C demonstrated promising potential as a candidate biomarker for breast cancer diagnosis.However,validation in prospective settings and by other study groups is warranted.Ya Wang Long Qiao Jie Yang Xiong Li Yaqi Duan Jiahao Liu Shaoqi Chen Huayi Li Dan Liu Tian Fang Jingjing Ma Xiaoting Li Fei Ye Junxiang Wan Juncheng Wei Qin Xu Ensong Guo Ping Jin Mingfu Wu Lin Zhang Yun Xia Yaqun Wu Jun Shao Yaojun Feng Qing Zhang Zongyuan Yang Gang Chen Qinghua Zhang Xingrui Li Shixuan Wang Junbo Hu Xiaoyun Wang Mona P.Tan Kazuaki Takabe Beihua Kong Qifeng Yang Ding Ma Qinglei Gao 2021Cancer Communications2021,41,12:3
13Pose optimization based on integral of the distance between line segments显示文摘In this paper, new solutions for the problem of pose estimation from correspondences between 3D model lines and 2D image lines are proposed. Traditional line-based pose estimation methods rely on the assumption that the noises(perpendicular to the line) for the two endpoints are statistically independent. However, these two noises are in fact negatively correlated when the image line segment is fitted using the least-squares technique. Therefore, we design a new error function expressed by the average integral of the distance between line segments. Three least-squares techniques that optimize both the rotation and translation simultaneously are proposed in which the new error function is exploited. In addition, Lie group formalism is utilized to describe the pose parameters, and then, the optimization problem can be solved by means of a simple iterative least squares method. To enhance the robustness to outliers existing in the match data, an M-estimation method is developed to convert the pose optimization problem into an iterative reweighted least squares problem. The proposed methods are validated through experiments using both synthetic and real-world data. The experimental results show that the proposed methods yield a clearly higher precision than the traditional methods.ZHANG YueQiang LI Xin LIU HaiBo SHANG Yang YU QiFeng 2016Science China(Technological Sciences)2016,59,1:3
14Prognostic and incremental value of computed tomography-based radiomics from tumor and nodal regions in esophageal squamous cell carcinoma显示文摘Objective:This study aimed to evaluate the prognostic value of preoperative radiomics and establish an integrated model for esophageal squamous cell cancer(ESCC).Methods:A total of 931 patients were retrospectively enrolled in this study(training cohort,n=624;validation cohort,n=307).Radiomics features were obtained by contrast-enhanced computed tomography(CT)before esophagectomy.A radiomics index was set based on features of tumor and reginal lymph nodes by using the least absolute shrinkage and selection operator(LASSO)Cox regression.Prognostic nomogram was built based on radiomics index and other independent risk factors.The prognostic value was assessed by using Harrell’s concordance index,time-dependent receiver operating characteristics and Kaplan-Meier curves.Results:Twelve radiomic features from tumor and lymph node regions were identified to build a radiomics index,which was significantly associated with overall survival(OS)in both training cohort and validation cohort.The radiomics index was highly correlated with clinical tumor-node-metastasis(cTNM)and pathologic TNM(pTNM)stages,but it demonstrated a better prognostic value compared with cTNM stage and was almost comparable with pTNM stage.Multivariable Cox regression showed that the radiomics index was an independent prognostic factor.An integrated model was constructed based on gender,preoperative serum sodium concentration,pTNM and the radiomics index for clinical usefulness.The integrated model demonstrated discriminatory ability better compared with the traditional clinical-pathologic model and pTNM alone,indicating incremental value for prognosis.Conclusions:CT-based radiomics for primary tumor and reginal lymph nodes was sufficient in predicting OS for patients with ESCC.The integrated model demonstrated incremental value for prognosis and was robust for clinical applications.Bangrong Cao Kun Mi Wei Dai Tong Liu Tianpeng Xie Qiang Li Jinyi Lang Yongtao Han Lin Peng Qifeng Wang 2022Chinese Journal of Cancer Research2022,34,2:3
15Low power and high uniformity of HfO_x-based RRAM via tip-enhanced electric fields显示文摘In this paper, the HfO_x-based resistive random access memory(RRAM) devices with sub-100 nm pyramid-type electrodes were fabricated. With the help of tip-enhanced electric field around the pyramid-type electrodes, it was experimentally demonstrated that the novel devices have better cycle-to-cycle variation control, lower forming/set voltage(1.97/0.7V) and faster switching speed(≤30 ns under 0.9V pulse) as well as better endurance reliability than conventional flat electrode resistive memory devices. In addition,the novel RRAM is experimentally demonstrated with independence of electrode number for the first time to present great potential in scaling down. This novel structure metal-oxide based RRAM will be suitable for the future low-power non-volatile memory application.Xiaokang LI Baotong ZHANG Bowen WANG Xiaoyan XU Yuancheng YANG Shuang SUN Qifeng CAI Shijie HU Xia AN Ming LI Ru HUANG 2019Science China(Information Sciences)2019,62,10:3
16Full-parameter vision navigation based on scene matching for aircrafts显示文摘Vision navigation based on scene matching between real-time images and a reference image has many advantages over the commonly used inertial navigation system(INS),such as no cumulative measurement errors for long-endurance flight.Recent developments in vision navigation are mainly used for partial navigation parameters measurements,such as the position and the relative velocity,which cannot meet the requirements of completely autonomous navigation.We present the concept,principle and method of full-parameter vision navigation(FPVN)based on scene matching.The proposed method can obtain the three-dimensional(3D)position and attitude angles of an aircraft by the scene matching for multiple feature points instead of a single point in existing vision navigations.Thus,FPVN can achieve the geodetic position coordinates and attitude angles of the aircraft and then the velocity vector,attitude angular velocity and acceleration can be derived by the time differentials,which provide a full set of navigation parameters for aircrafts and unmanned aerial vehicles(UAVs).The method can be combined with the INS and the cumulative errors of the INS can be corrected using the measurements of FPVN rather than satellite navigation systems.The approach provides a completely autonomous and accurate navigation method for long-endurance flight without the help of satellites.YU QiFeng SHANG Yang LIU XiaoChun LEI ZhiHui LI Xiang ZHU XianWei LIU XiaoLin YANG Xia SU Ang ZHANG XiaoHu ZHANG HongLiang 2014Science China(Information Sciences)2014,57,5:3
17Super-resolution reconstruction and higher-degree function deformation model based matching for Chang’E-1 lunar images显示文摘This article intends to solve the matching problem of 2C level lunar images by Chang’E-1(CE-1)lunar probe satellite.A line-scanner image matching method is proposed which represents deformation by the quadric function along the camera motion direction and bases on the deformation model for a relief terrain’s imaging on sensors of the satellite borne three-line scanner camera.A precise matching is carried out for the normal view,the frontward view,and the backward view images of the CE-1 by combining the proposed method with the standard correlation method.A super-resolution(SR)reconstruction algorithm based on the wavelet interpolation of non-uniformly sampled data is also adopted to realize SR reconstruction of CE-1 lunar images,which adds the recognizable targets and explores CE-1 lunar images to the full.LI LiChun YU QiFeng YUAN Yun SHANG Yang LU HongWei SUN XiangYi 2009Science China(Technological Sciences)2009,52,12:3
18Numerical investigation on effects of side curtain opening behavior on indoor climate of naturally ventilated dairy buildings显示文摘The side-curtain is popular in cattle buildings to regulate indoor climates and ventilation rates by adjusting the opening ratio.It normally had three different adjusting strategies relate to the position of rollers,i.e.central roller(S1),top roller(S2)and bottom roller(S3),which result in different opening behaviors to generate the same opening ratio but different opening positions in the side wall for a full-curtain house.Numerical simulations were conducted using computational fluid dynamics(CFD)to investigate the effects of the eight potential opening behaviors of side curtains on the indoor climates and airflow rates in winter for a typical naturally ventilated dairy house in China when the opening ratio were 8.5%and 17%.Airflow patterns,wind chilled temperature(WCT)and age of air were analyzed in the animal occupied zone(AOZ)by taking reference planes.Openings at the very bottom of side walls had more efficient ventilation due to the younger air age,more effective air disturbing,more uniformly distributed indicators in AOZ.However,it will result in a lower WCT in AOZ although a lower ventilation rate was observed in this case.Openings on the very top of side wall would generate a better thermal comfort in AOZ but with very poor air quality and nonuniformly distributed airflows in the dairy house.S1 was not recommended to the practical application due to the poor indoor climate and the higher cost of the mechanical structure.Based on the comprehensive evaluations of the analytic hierarchy process,the most satisfaction opening positions were at the bottom of the side curtains and the optimized adjusting strategy is S2.Qifeng Li Chuanxia Yao Luyu Ding Ligen Yu Weihong Ma Ronghua Gao Wengang Zheng 2020International Journal of Agricultural and Biological Engineering2020,13,5:2
19Understanding the role of tungsten on Pt/CeO_(2)for vinyl chloride catalytic combustion显示文摘Spherical CeO_(2)synthesized by the hydrothermal process was used as support to prepare Pt/WO_(3)/CeO_(2),and the effects of tungsten(W)contents on activity,stability and polychlorinated by-products were investigated to understand the role of W for vinyl chloride(VC)catalytic oxidation.The introduction of12 wt%W to Pt/CeO_(2)(P12 WC)exhibits the highest catalytic activity with 90%conversion of VC at 250℃,meanwhile the stability improves and the polychlorinated by-products in the tail gas significantly decrease due to the removal of dissociated Cl species in the formation of HCl.The beneficial effects of W on Pt/CeO_(2)are closely related to the chemical state of Pt,redox and surface acid sites distribution.The doped W not only makes Pt disperse evenly on the support with the high valence,but also weakens the interaction between Pt and CeO_(2)by the formation of Pt-O-W and Pt-O-W-O-Ce species,which facilitates oxygen mobility.In addition,the modification of W species also significantly increases the surface acidity amount and changes the distribution of acid sites.Qifeng Zhang Zhengbo Zhou Tian Fang Han Gu Yanglong Guo Wangcheng Zhan Yun Guo Li Wang 2022Journal of Rare Earths2022,40,9:2
20Biological receptor-inspired flexible artificial synapse based on ionic dynamics显示文摘The memristor has been regarded as a promising candidate for constructing a neuromorphic computing platform that is capable of confronting the bottleneck of the traditional von Neumann architecture.Here,inspired by the working mechanism of the G-protein-linked receptor of biological cells,a novel double-layer memristive device with reduced graphene oxide(rGO)nanosheets covered by chitosan(an ionic conductive polymer)as the channel material is constructed.The protons in chitosan and the functional groups in rGO nanosheets imitate the functions of the ligands and receptors of biological cells,respectively.Smooth changes in the response current depending on the historical applied voltages are observed,offering a promising pathway toward biorealistic synaptic emulation.The memristive behavior is mainly a result of the interaction between protons provided by chitosan and the defects and functional groups in the rGO nanosheets.The channel current is due to the hopping of protons through functional groups and is limited by the traps in the rGO nanosheets.The transition from short-term to long-term potentiation is achieved,and learning-forgetting behaviors of the memristor mimicking those of the human brain are demonstrated.Overall,the bioinspired memristor-type artificial synaptic device shows great potential in neuromorphic networks.Qifeng Lu Fuqin Sun Lin Liu Lianhui Li Yingyi Wang Mingming Hao Zihao Wang Shuqi Wang Ting Zhang 2020Microsystems & Nanoengineering2020,6,1:2
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