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Clinical value of precise rehabilitation nursing in management of cerebral infarction 被引量:1
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作者 Ya-Na Xu Xiu-Zhen Wang Xiao-Rong Zhang 《World Journal of Clinical Cases》 SCIE 2024年第1期24-31,共8页
BACKGROUND Cerebral infarction,previously referred to as cerebral infarction or ischemic stroke,refers to the localized brain tissue experiencing ischemic necrosis or softening due to disorders in brain blood supply,i... BACKGROUND Cerebral infarction,previously referred to as cerebral infarction or ischemic stroke,refers to the localized brain tissue experiencing ischemic necrosis or softening due to disorders in brain blood supply,ischemia,and hypoxia.The precision rehabilitation nursing model for chronic disease management is a continuous,fixed,orderly,and efficient nursing model aimed at standardizing the clinical nursing process,reducing the wastage of medical resources,and improving the quality of medical services.AIM To analyze the value of a precise rehabilitation nursing model for chronic disease management in patients with cerebral infarction.METHODS Patients(n=124)admitted to our hospital with cerebral infarction between November 2019 and November 2021 were enrolled as the study subjects.The random number table method was used to divide them into a conventional nursing intervention group(n=61)and a model nursing intervention group(n=63).Changes in the nursing index for the two groups were compared after conventional nursing intervention and precise rehabilitation intervention nursing for chronic disease management.RESULTS Compared with the conventional intervention group,the model intervention group had a shorter time to clinical symptom relief(P<0.05),lower Hamilton Anxiety Scale and Hamilton Depression Scale scores,a lower incidence of total complications(P<0.05),a higher disease knowledge mastery rate,higher safety and quality,and a higher overall nursing satisfaction rate(P<0.05).CONCLUSION The precision rehabilitation nursing model for chronic disease management improves the clinical symptoms of patients with cerebral infarction,reducing the incidence of total complications and improving the clinical outcome of patients,and is worthy of application in clinical practice. 展开更多
关键词 precise rehabilitation nursing model for chronic disease management Cerebral infarction Knowledge of disease Safety and quality
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Fish-on-Chips:unveiling neural processing of chemicals in small animals through precise fluidic control
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作者 Samuel K.H.Sy Ho Ko 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第11期2351-2353,共3页
Precise chemical cue presentation alongside advanced brainwide imaging techniques is important to the study of chemosensory processing in animals.Nevertheless,the dynamic nature of chemical-carrying media,such as wate... Precise chemical cue presentation alongside advanced brainwide imaging techniques is important to the study of chemosensory processing in animals.Nevertheless,the dynamic nature of chemical-carrying media,such as water or air,poses a significant challenge for delivering highly-controlled chemical flow to an animal subject.Moreover,contact-based cue manipulation and delivery easily shift the position of the animal subject,which is often undesirable for high-quality brain imaging.Additionally,more advanced interfacing tools that align with the diverse range of body part sizes of an animal,ranging from micrometer-scale neurons to meter-long limbs,are much needed.This is particularly crucial when dealing with dimensions that are beyond the reach of conventional experimental tools. 展开更多
关键词 dealing precise SIZES
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Self-consistent and precise measurement of time-dependent radiative albedo of gold based on specially symmetrical triple-cavity Hohlraum
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作者 Zhiyu Zhang Yang Zhao +19 位作者 Xiaoying Han Liling Li Bo Qing Lifei Hou Yulong Li YuXue Zhang Huan Zhang Xiangming Liu Bo Deng Gang Xiong Min Lv Tuo Zhu Chengwu Huang Tianming Song Yan Zhao Yingjie Li Lu Zhang Xufei Xie Jiyan Zhang Jiamin Yang 《Matter and Radiation at Extremes》 SCIE EI CSCD 2024年第3期57-64,共8页
A self-consistent and precise method to determine the time-dependent radiative albedo,i.e.,the ratio of the reemission flux to the incident flux,for an indirect-drive inertial confinement fusion Hohlraum wall material... A self-consistent and precise method to determine the time-dependent radiative albedo,i.e.,the ratio of the reemission flux to the incident flux,for an indirect-drive inertial confinement fusion Hohlraum wall material is proposed.A specially designed symmetrical triple-cavity gold Hohlraum is used to create approximately constant and near-equilibrium uniform radiation with a peak temperature of 160 eV.The incident flux at the secondary cavity waist is obtained from flux balance analysis and from the shock velocity of a standard sample.The results agree well owing to the symmetrical radiation in the secondary cavity.A self-consistent and precise time-dependent radiative albedo is deduced from the reliable reemission flux and the incident flux,and the result from the shock velocity is found to have a smaller uncertainty than that from the multi-angle flux balance analysis,and also to agree well with the result of a simulation using the HYADES opacity. 展开更多
关键词 precise cavity RADIATIVE
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Caliper-based precise positioning of the target(CALIPPOT)for transcranial magnetic stimulation without neuronavigation system
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作者 Yunsong Hu Rong Zeng +5 位作者 Juan Yue Qiu Ge Hongxiao Wang Zijian Feng Jue Wang Yufeng Zang 《General Psychiatry》 CSCD 2024年第2期311-314,共4页
To the editor:Transcranial magnetic stimulation(TMS)is a non-invasive brain modulation technique.One important usage of TMS is the transient interruption of cognitive brain function(also named virtual lesion)for inves... To the editor:Transcranial magnetic stimulation(TMS)is a non-invasive brain modulation technique.One important usage of TMS is the transient interruption of cognitive brain function(also named virtual lesion)for investigating precisely where and when a specific cortical region contributes to a specific cognitive function.1 A more important usage of TMS is the treatment of brain disorders by repetitive TMS(rTMS). 展开更多
关键词 STIMULATION technique. precise
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Methanol steam reforming for hydrogen production driven by an atomically precise Cu catalyst
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作者 Weigang Hu Haoqi Liu +7 位作者 Yuankun Zhang Jiawei Ji Guangjun Li Xiao Cai Xu Liu Wen Wu Xu Weiping Ding Yan Zhu 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第7期1079-1084,共6页
Plasmon-induced hot-electron transfer from metal nanostructures is being intensely pursed in current photocatalytic research,however it remains elusive whether molecular-like metal clusters with excitonic behavior can... Plasmon-induced hot-electron transfer from metal nanostructures is being intensely pursed in current photocatalytic research,however it remains elusive whether molecular-like metal clusters with excitonic behavior can be used as light-harvesting materials in solar energy utilization such as photocatalytic methanol steam reforming.In this work,we report an atomically precise Cu_(13)cluster protected by dual ligands of thiolate and phosphine that can be viewed as the assembly of one top Cu atom and three Cu_(4)tetrahedra.The Cu_(13)H_(10)(SR)_(3)(PR’_(3))_(7)(SR=2,4-dichlorobenzenethiol,PR’_(3)=P(4-FC_(6)H_(4))_(3))cluster can give rise to highly efficient light-driven activity for methanol steam reforming toward H_(2)production. 展开更多
关键词 NANOCLUSTER PHOTOCATALYSIS Methanol steam reforming Atomically precise Copper catalyst
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Review of the development of Lunar Laser Ranging
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作者 Kai Huang Yongzhang Yang +5 位作者 Rufeng Tang Jin Cao Marco Muccino Luca Porcelli Simone Dell'Agnello Yuqiang Li 《Astronomical Techniques and Instruments》 CSCD 2024年第6期295-306,共12页
This paper provides a comprehensive overview of the development of Lunar Laser Ranging(LLR),covering key components such as ground observatories,lunar retro-reflectors,and data formats.The paper details the evolution ... This paper provides a comprehensive overview of the development of Lunar Laser Ranging(LLR),covering key components such as ground observatories,lunar retro-reflectors,and data formats.The paper details the evolution of LLR experiments conducted by some major world-class observatories,with a particular focus on addressing critical issues associated with LLR technology.Additionally,the article highlights the latest advancements in the field,elucidating scientific achievements derived from LLR data,including its contributions to gravitational theory,Earth Orientation Parameters,lunar physics exploration,and lunar librations.The review summarizes new challenges in LLR modeling and concludes with prospects for the future development of LLR. 展开更多
关键词 Lunar Laser ranging Retro-reflectors OBSERVATORIES GRAVITY
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Beidou receiver based on anti-jamming antenna arrays with self-calibration for precise relative positioning
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作者 AN Yi KANG Ronglei +1 位作者 BAN Yalong YANG Shaoshuai 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第5期1132-1147,共16页
Unmanned aerial vehicles(UAVs)may be subjected to unintentional radio frequency interference(RFI)or hostile jamming attack which will lead to fail to track global navigation satellite system(GNSS)signals.Therefore,the... Unmanned aerial vehicles(UAVs)may be subjected to unintentional radio frequency interference(RFI)or hostile jamming attack which will lead to fail to track global navigation satellite system(GNSS)signals.Therefore,the simultaneous realization of anti-jamming and high-precision carrier phase difference positioning becomes a dilemmatic problem.In this paper,a distortionless phase digital beamforming(DBF)algorithm with self-calibration antenna arrays is proposed,which enables to obtain distortionless carrier phase while suppressing jamming.Additionally,architecture of high precision Beidou receiver based on anti-jamming antenna arrays is proposed.Finally,the performance of the algorithm is evaluated,including antenna calibration accuracy,carrier phase distortionless accuracy,and carrier phase measurement accuracy without jamming.Meanwhile,the maximal jamming to signal ratio(JSR)and real time kinematic(RTK)positioning accuracy under wideband jamming are also investigated.The experimental results based on the real-life Beidou signals show that the proposed method has an excellent performance for precise relative positioning under jamming when compared with other anti-jamming methods. 展开更多
关键词 Beidou receiver antenna array ANTI-JAMMING high precision distortionless carrier phase
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Hybrid pedestrian positioning system using wearable inertial sensors and ultrasonic ranging
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作者 Lin Qi Yu Liu +2 位作者 Chuanshun Gao Tao Feng Yue Yu 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期327-338,共12页
Pedestrian positioning system(PPS)using wearable inertial sensors has wide applications towards various emerging fields such as smart healthcare,emergency rescue,soldier positioning,etc.The performance of traditional ... Pedestrian positioning system(PPS)using wearable inertial sensors has wide applications towards various emerging fields such as smart healthcare,emergency rescue,soldier positioning,etc.The performance of traditional PPS is limited by the cumulative error of inertial sensors,complex motion modes of pedestrians,and the low robustness of the multi-sensor collaboration structure.This paper presents a hybrid pedestrian positioning system using the combination of wearable inertial sensors and ultrasonic ranging(H-PPS).A robust two nodes integration structure is developed to adaptively combine the motion data acquired from the single waist-mounted and foot-mounted node,and enhanced by a novel ellipsoid constraint model.In addition,a deep-learning-based walking speed estimator is proposed by considering all the motion features provided by different nodes,which effectively reduces the cumulative error originating from inertial sensors.Finally,a comprehensive data and model dual-driven model is presented to effectively combine the motion data provided by different sensor nodes and walking speed estimator,and multi-level constraints are extracted to further improve the performance of the overall system.Experimental results indicate that the proposed H-PPS significantly improves the performance of the single PPS and outperforms existing algorithms in accuracy index under complex indoor scenarios. 展开更多
关键词 Pedestrian positioning system Wearable inertial sensors Ultrasonic ranging Deep-learning Data and model dual-driven
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Development and Therapeutic Applications of Precise Gene Editing Technology
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作者 ZHANG Yi-Meng YANG Xiao +1 位作者 WANG Jian LI Zhen-Hua 《生物化学与生物物理进展》 SCIE CAS CSCD 北大核心 2024年第10期2637-2647,共11页
The advent of gene editing represents one of the most transformative breakthroughs in life science,making genome manipulation more accessible than ever before.While traditional CRISPR/Cas-based gene editing,which invo... The advent of gene editing represents one of the most transformative breakthroughs in life science,making genome manipulation more accessible than ever before.While traditional CRISPR/Cas-based gene editing,which involves double-strand DNA breaks(DSBs),excels at gene disruption,it is less effective for accurate gene modification.The limitation arises because DSBs are primarily repaired via non-homologous end joining(NHEJ),which tends to introduce indels at the break site.While homology directed repair(HDR)can achieve precise editing when a donor DNA template is provided,the reliance on DSBs often results in unintended genome damage.HDR is restricted to specific cell cycle phases,limiting its application.Currently,gene editing has evolved to unprecedented levels of precision without relying on DSB and HDR.The development of innovative systems,such as base editing,prime editing,and CRISPR-associated transposases(CASTs),now allow for precise editing ranging from single nucleotides to large DNA fragments.Base editors(BEs)enable the direct conversion of one nucleotide to another,and prime editors(PEs)further expand gene editing capabilities by allowing for the insertion,deletion,or alteration of small DNA fragments.The CAST system,a recent innovation,allows for the precise insertion of large DNA fragments at specific genomic locations.In recent years,the optimization of these precise gene editing tools has led to significant improvements in editing efficiency,specificity,and versatility,with advancements such as the creation of base editors for nucleotide transversions,enhanced prime editing systems for more efficient and precise modifications,and refined CAST systems for targeted large DNA insertions,expanding the range of applications for these tools.Concurrently,these advances are complemented by significant improvements in in vivo delivery methods,which have paved the way for therapeutic application of precise gene editing tools.Effective delivery systems are critical for the success of gene therapies,and recent developments in both viral and non-viral vectors have improved the efficiency and safety of gene editing.For instance,adeno-associated viruses(AAVs)are widely used due to their high transfection efficiency and low immunogenicity,though challenges such as limited cargo capacity and potential for immune responses remain.Non-viral delivery systems,including lipid nanoparticles(LNPs),offer an alternative with lower immunogenicity and higher payload capacity,although their transfection efficiency can be lower.The therapeutic potential of these precise gene editing technologies is vast,particularly in treating genetic disorders.Preclinical studies have demonstrated the effectiveness of base editing in correcting genetic mutations responsible for diseases such as cardiomyopathy,liver disease,and hereditary hearing loss.These technologies promise to treat symptoms and potentially cure the underlying genetic causes of these conditions.Meanwhile,challenges remain,such as optimizing the safety and specificity of gene editing tools,improving delivery systems,and overcoming off-target effects,all of which are critical for their successful application in clinical settings.In summary,the continuous evolution of precise gene editing technologies,combined with advancements in delivery systems,is driving the field toward new therapeutic applications that can potentially transform the treatment of genetic disorders by targeting their root causes. 展开更多
关键词 precise gene editing CRISPR/Cas system base editing prime editing gene therapy
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Performance of GNSS positioning in PPP mode using MADOCA precise products
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作者 Brian Bramanto Rachel Theresia +1 位作者 Irwan Gumilar Sidik T.Wibowo 《Geodesy and Geodynamics》 EI CSCD 2024年第6期642-651,共10页
The Global Navigation Satellite System (GNSS) is widely utilized for accurate positioning.One commonly applied method to obtain precise coordinate estimates is by implementing the relative positioning in network mode.... The Global Navigation Satellite System (GNSS) is widely utilized for accurate positioning.One commonly applied method to obtain precise coordinate estimates is by implementing the relative positioning in network mode.However,this approach can be complex and challenging.Fortunately,The Japan Aerospace Exploration Agency (JAXA) offers freely available satellite orbit and clock correction products called Multi-GNSS Advanced Demonstration Tool for Orbit and Clock Analysis (MADOCA),which can enhance positioning accuracy through the precise point positioning (PPP) method.This study focuses on evaluating PPP static mode positioning using MADOCA products and comparing the results with the highly precise relative positioning method.By analyzing a network of 20 GNSS stations in Indonesia,we found that the PPP method using MADOCA products provided favorable positioning estimates.The median discrepancies and the corresponding median absolute deviation (MAD) for easting,northing,and up components were estimated as 9±18 mm,10±9 mm,and 3±40 mm,respectively.These results indicate that PPP with MADOCA products can be a reliable alternative for establishing Indonesia's horizontal control networks,particularly for orders 0,1,2,and 3,and for a broad spectrum of geoscience monitoring activities.However,considerations such as epoch transformations and seismic activities should be taken into account for accurate positioning applications that comply with the definition of the national reference framework. 展开更多
关键词 Global Navigation Satellite System(GNSS) precise point positioning(PPP) MADOCA Positioning evaluation
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Performance Evaluation of Low-Cost Dual-Frequency GNSS Receivers for Precise Positioning in Senegal: Issues and Challenges
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作者 Diogoye Diouf Oustasse Abdoulaye Sall +1 位作者 Ibrahima Khalil Gueye Fatou Ndiaye 《Journal of Analytical Sciences, Methods and Instrumentation》 2024年第2期23-37,共15页
The development of this technology has favored the advances noted in recent years in the field of precise positioning. It has also paved the way for a wide range of research into the evaluation of their performance an... The development of this technology has favored the advances noted in recent years in the field of precise positioning. It has also paved the way for a wide range of research into the evaluation of their performance and reliability, their potential use in different fields, the improvement of performance and combined systems, etc. Single-frequency GNSS receivers, which for a long time remained the only category of low-cost GNSS receivers, often limited by their level of accuracy (metric) mainly due to their single-frequency nature, have been joined in the last decade by dual-frequency GNSS receivers developed by certain manufacturers of positioning equipment. These receivers now offer possible alternatives to the relatively expensive conventional (topographic quality) or geodetic receivers and. In this study, the performance of these low-cost dual-frequency receivers was evaluated in static and real-time kinematic GNSS positioning modes. Static positioning was carried out on three points with sessions of 2 h and 4 h over three days with antenna swapping (CHC i50, Leica GS14 and Emlid Reach RS2+). Real-time observations were carried out on eleven (11) points in open, poorly open and not at all open environments, in order to assess not only performance but also receiver sensitivity in environments with a high risk of multipath. The results obtained showed an average agreement of 2 cm in planimetry between the low-cost Emlid RS2+ receiver and the Leica GS14 and CHC i50 receivers. The differences in altimetry are nevertheless greater (sometimes up to decimetres for certain points). Real-time positioning results provided an average convergence of around 1 cm on the E, N and H components with the results from the low-cost Emlid Reach RS2+ and Ublox ZED-F9P receivers and the CHC i50 receiver. Analysis of the results obtained has enabled us to highlight the various issues and challenges associated with this new generation of GNSS receivers, with a view to enhancing their appropriation and optimal integration in the professional and research worlds. 展开更多
关键词 Low-Cost GNSS NRTK precise Positioning ISSUES CHALLENGES
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High precision and sensitivity anti-interference 3D coherent ranging based on dual reversely chirped self-mixing lasers
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作者 Chenxiao Lin Yifan Wang Yidong Tan 《Advanced Photonics Nexus》 2024年第6期16-30,共15页
Frequency-modulated continuous-wave light detection and ranging(FMCW lidar)is a powerful high-precision ranging and three-dimensional(3D)imaging technology with inherent immunity to ambient light and the ability to si... Frequency-modulated continuous-wave light detection and ranging(FMCW lidar)is a powerful high-precision ranging and three-dimensional(3D)imaging technology with inherent immunity to ambient light and the ability to simultaneously yield distance and velocity information.However,the current withdraws of the traditional FMCW lidar systems are the poor resistance to environmental disturbance and high requirements for echo power,which greatly restrict their applications for high-precision ranging of noncooperative targets in dynamic measurement scenes.Here,we report an all-fiber anti-interference FMCW lidar system with high sensitivity and precision,employing a unique self-mixing stimulation radiation process for signal amplification,a special reversely chirped dual laser structure,and a common-path design for disturbance compensation.We evaluate the ranging accuracy,precision,and stability of the system completely.Finally,we demonstrate an ultralow echo detection limit of subpicowatts with a probe power of below 0.1 mW,a state-of-art localization accuracy of better than 50μm,high stability with a standard deviation of 6.51μm over 3 h,and high-quality 3D imaging of noncooperative objects in a fluctuating environment.With the advantages of high precision and stability,weak signal detection capability,and anti-interference ability,the proposed system has potential applications in space exploration,autodriving,and high-precision manufacturing. 展开更多
关键词 FMCW lidar optical imaging self-mixing interferometry environmental disturbance precision metrology
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Empowerment of Precise Ideological and Political Education in Higher Education with Educational Digitalization
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作者 Yan Dong Yu Yu Ge Yao 《Journal of Contemporary Educational Research》 2024年第4期23-28,共6页
The study explores how educational digitalization enables the precise development of ideological and political education in colleges and universities.Digital transformation enables colleges and universities to accurat... The study explores how educational digitalization enables the precise development of ideological and political education in colleges and universities.Digital transformation enables colleges and universities to accurately define educational objectives,content strategies,effect evaluation,and process management,and realize the precision and intelligence of ideological and political education.The application of big data technology enhances the data-oriented thinking of teachers and students,promotes the accurate application of data,and improves the efficiency of ideological and political education.The research also prospected a new vision of the digital construction of ideological and political courses and clarified the theoretical and practical path of the implementation and evaluation mode of ideological and political courses under digital empowerment.Education digitalization enables precise ideological and political education,which is a key way to promote the innovative development of ideological and political education in colleges and universities and will strongly support the improvement of the overall quality of higher education and the training of excellent talents. 展开更多
关键词 Education digital empowerment precise ideological and political education Improvement of efficiency
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精准饲喂对个体奶牛甲烷排量的影响
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作者 叶岩 崔振兴 +4 位作者 李源源 杨存志 侯云涛 李尧 孙先明 《农机化研究》 北大核心 2025年第3期156-161,共6页
反刍动物奶牛的甲烷排放是农业温室气体主要排放源之一,而采食量是影响个体奶牛甲烷排量的重要因素,故研制个体奶牛精准饲喂系统和利用甲烷检测装置分析奶牛采食量对甲烷排量的影响,对提高奶牛健康水平、提高饲料利用率和奶牛科学饲养... 反刍动物奶牛的甲烷排放是农业温室气体主要排放源之一,而采食量是影响个体奶牛甲烷排量的重要因素,故研制个体奶牛精准饲喂系统和利用甲烷检测装置分析奶牛采食量对甲烷排量的影响,对提高奶牛健康水平、提高饲料利用率和奶牛科学饲养管理能力等方面均具有重要意义。为此,设计了个体奶牛精准饲喂系统和甲烷检测装置,利用个体奶牛穿戴式“牛衣”和牧场内主体框架分布网点固定安装相结合的方法,采集对照组和试验组各3头奶牛采食前后奶牛后肠道甲烷排量和奶牛嗳气与呼吸的甲烷排量。研究表明,个体奶牛精准饲喂系统可依据奶牛个体差异实现饲料的定量饲喂,相同条件下精准饲喂和自由采食的个体奶牛甲烷排量和产奶量有差异但不显著,且随着个体奶牛采食量增加,甲烷排量会随之升高,说明饲喂量与甲烷排量之间存在正相关关系。 展开更多
关键词 精准饲喂 甲烷排量 奶牛
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同轴反应流反应速率的唯象表征与影响规律研究
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作者 李瑜 樊义辉 +3 位作者 卞平艳 张海光 曲海军 王建平 《河南理工大学学报(自然科学版)》 CAS 北大核心 2025年第1期109-116,共8页
目的 为了提高同轴反应流工艺的控制精度,探索反应速率的宏观唯象表征方法和影响规律,方法 通过紫脲酸铵对Ca2+进行示踪,在线观测海藻酸钙水凝胶中空纤维的交联成形过程,利用洗脱法对交联层边界的灰度阈值进行标定,从宏观唯象的角度定... 目的 为了提高同轴反应流工艺的控制精度,探索反应速率的宏观唯象表征方法和影响规律,方法 通过紫脲酸铵对Ca2+进行示踪,在线观测海藻酸钙水凝胶中空纤维的交联成形过程,利用洗脱法对交联层边界的灰度阈值进行标定,从宏观唯象的角度定义同轴反应流的平均反应速率,通过在线监测提取的交联层厚数据,计算得到反应速率值,并通过试验研究海藻酸钠和氯化钙溶液的流量(定流率比)、质量分数、共流距离对交联层厚和平均反应速率的影响规律。结果 结果表明:对比在线图像识别和洗脱法实测所得中空纤维尺寸,两者误差仅1.09%,满足工程应用需求;增加反应物质量分数能提高平均反应速率,增加交联层厚,且氯化钙质量分数具有更好的调控性能;定流率比条件下,随着两溶液流速增加,中空纤维交联层厚减小而平均反应速率增大;随着反应流共流距离增加,交联层厚增加而平均反应速率逐渐减小。上述唯象平均反应速率受流体速度场和化学反应物质量分数的影响规律与经典反应速率是一致的,说明该唯象定义是有效的。结论 研究采用的同轴反应流在线监测方法、反应速率的唯象表征方法、材料工艺参数影响规律等有助于实现中空纤维结构尺寸、交联层厚和保留溶胶层厚的精确控制,有助于同轴反应流工艺的推广与应用。 展开更多
关键词 同轴挤出 反应流 反应速率 唯象表征 精确控制
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游泳运动对大鼠创伤性关节挛缩的影响及机制
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作者 税晓平 李春莹 +5 位作者 张鑫 李彬 冯超 周宏宇 陈科 廖莹莹 《中国组织工程研究》 CAS 北大核心 2025年第2期262-268,共7页
背景:早期运动是预防创伤性关节挛缩的主要方式,也是近期研究热点。游泳运动借助水的特殊物理特性,可能是潜在有益的干预方式。目的:观察游泳运动对大鼠关节挛缩发展的影响,探究游泳运动预防关节挛缩的相关机制。方法:24只SD大鼠随机分... 背景:早期运动是预防创伤性关节挛缩的主要方式,也是近期研究热点。游泳运动借助水的特殊物理特性,可能是潜在有益的干预方式。目的:观察游泳运动对大鼠关节挛缩发展的影响,探究游泳运动预防关节挛缩的相关机制。方法:24只SD大鼠随机分为空白对照组(n=8)和关节挛缩造模组(n=16),手术制备膝关节挛缩模型后,再随机分为手术对照组(n=8)和游泳干预组(n=8)。游泳干预组在术后第2周开始游泳干预,共干预5周。在术后第6周,测试各组大鼠体质量、术侧膝关节活动度、股四头肌直径,计算直径-体质量指数;苏木精-伊红染色观察膝关节囊和股四头肌病理变化;Masson染色观察关节囊胶原纤维化改变;免疫组化检测膝关节囊中转化生长因子β1和Ⅰ型胶原蛋白表达;Western blot检测股四头肌中MuRF1蛋白的表达。结果与结论:①与空白对照组比较,手术对照组和游泳干预组大鼠膝关节活动度下降,总伸膝受限角度和关节源性伸膝受限角度均明显增加(P<0.01),股四头肌直径下降(P<0.01),关节囊出现明显纤维化表现,股四头肌萎缩,手术对照组直径-体质量指数降低(P<0.01);与手术对照组比较,游泳干预组大鼠膝关节活动度和股四头肌直径明显增加(P<0.01),关节囊纤维化病变和股四头肌萎缩明显改善;②与空白对照组比较,手术对照组和游泳干预组大鼠关节囊中胶原纤维含量、转化生长因子β1和Ⅰ型胶原蛋白表达均增加(P<0.01);与手术对照组比较,游泳干预组大鼠关节囊中胶原纤维含量、转化生长因子β1和Ⅰ型胶原蛋白表达均降低(P<0.01);③与空白对照组比较,手术对照组和游泳干预组大鼠股四头肌中MuRF1蛋白表达增加(P<0.05);与手术对照组比较,游泳干预组大鼠股四头肌中MuRF1蛋白表达降低(P<0.05)。结果表明:早期游泳干预能够降低创伤性挛缩大鼠关节囊中转化生长因子β1和Ⅰ型胶原蛋白表达,降低股四头肌中MuRF1蛋白表达,提高关节活动度和股四头肌直径,抑制关节挛缩的发展。 展开更多
关键词 关节挛缩 肌肉萎缩 游泳 运动 关节活动度 大鼠
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基于改进DGCNN的树木点云分割方法
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作者 刘超 卜鑫荣 +3 位作者 刘慧 杨官学 沈跃 徐婕 《南京农业大学学报》 CAS 北大核心 2025年第1期240-248,共9页
[目的]通过目标分割为果园喷雾机提供树木的表征信息,使喷雾机能够实现精准喷雾。在分割过程中,对苗圃中的树冠、树干等不同部位进行分割,可以帮助喷雾机对喷雾部分对靶,在果园或苗圃景观中实现自动导航以及精准喷药等操作。与图片相比... [目的]通过目标分割为果园喷雾机提供树木的表征信息,使喷雾机能够实现精准喷雾。在分割过程中,对苗圃中的树冠、树干等不同部位进行分割,可以帮助喷雾机对喷雾部分对靶,在果园或苗圃景观中实现自动导航以及精准喷药等操作。与图片相比,点云能够更好地表征树木的三维结构并且受照明条件影响小,因此针对点云树木设计分割算法更适合应用在果园、苗圃等室外环境作业的农业机械。[方法]本文基于DGCNN提出了一种分割精度准确、参数量小的树木点云分割网络——TSNet,它可以很容易被部署在果园喷雾机上。该网络主要具有以下特点:1)该网络是基于DGCNN改进的,可以更好实现点云分割任务;2)网络引入了连续递归门控卷积模块(g^(n)Conv),可以提高树木分割的准确率;3)为避免全局信息损失并增加信息传递效率,我们设计了权重通道用于特征传递。[结果]TSNet分割树木的mIoU达到90.08%,模型大小为0.72 M,优于PointNet、PointNet++、DGCNN、CurveNet、PointMLP和D-PointNet++等常用的点云分割算法。[结论]TSNet能够为苗圃树木检测识别和农业机器人作业提供更准确的感知信息。 展开更多
关键词 点云 树木分割 深度学习 精准喷雾 果园喷雾机
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智能精密播种机的优化设计
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作者 吴政 《农机化研究》 北大核心 2025年第1期114-119,共6页
智能精密播种机是一种自动化的农业设备,可大幅提高种植效率、减少种植成本。但是,目前智能精密播种机依赖高精度的传感器、控制系统和算法来实现准确的种子投放和深度控制,需要较高的技术要求和技术支持,且对于一些不规则形状的种子或... 智能精密播种机是一种自动化的农业设备,可大幅提高种植效率、减少种植成本。但是,目前智能精密播种机依赖高精度的传感器、控制系统和算法来实现准确的种子投放和深度控制,需要较高的技术要求和技术支持,且对于一些不规则形状的种子或大粒小种的种子,适应性较差。为此,提出了一种智能精密播种机优化方案,并使用高精度传感器和控制系统实现多功能播种,控制种子的投放量和调整播种深度,使用节能设备模块化设计和使用易于更换的部件、数据分析功能和简单易用的用户界面。最后,通过田间试验进行功能性试验,结果表明:经过优化后的智能精密播种机播种变异系数≤5%,满足播种农艺要求,可以实现准确的种子投放和深度控制,避免种植密度不均匀和深度不一致等问题,从而提高种植效率和作物品质。 展开更多
关键词 智能精密播种机 优化设计 精度 多功能性 种植效率
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面向精密实验的飞秒激光精密加工技术研究进展
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作者 何煦 马云灿 +10 位作者 马骁 曹柱荣 喻寅 银颖 李晶 杨靖 孟立民 李军 陶天炯 杨昊 蒋均 《强激光与粒子束》 北大核心 2025年第1期134-146,共13页
飞秒激光精密加工技术具备极短脉冲宽度避免或缓解热效应、极高峰值功率密度适用于任意固体材料、极小焦斑尺寸实现微区精准去除或改性等三个方面的特性,满足精密诊断/测量实验涉及的各类难加工及特种材料的安全精密加工需求。高稳定性... 飞秒激光精密加工技术具备极短脉冲宽度避免或缓解热效应、极高峰值功率密度适用于任意固体材料、极小焦斑尺寸实现微区精准去除或改性等三个方面的特性,满足精密诊断/测量实验涉及的各类难加工及特种材料的安全精密加工需求。高稳定性高重复频率飞秒激光器的应用,弥补了低重复频率飞秒激光难以实现高速扫描的不足,这为精密实验所需各类精密样品/样件的高效精密加工提供了重要能量源。以中国工程物理研究院各研究所精密实验对精密样品的安全高效精密加工需求为切入点,分别以激光X射线精密靶材及结构、炸药材料微结构、超硬材料复合折射透镜结构、微型探头光纤精密固定结构、太赫兹滤波器核心结构等典型应用场景为例,介绍了高重频飞秒激光精密加工技术在难加工材料和特种材料安全高效精密加工方面的研究进展。 展开更多
关键词 飞秒激光 精密加工 金属材料 炸药材料 超硬材料
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利用匹配滤波的调频连续波激光测距技术研究
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作者 张鹏 封治华 +5 位作者 张鹏飞 赵渊明 阮友田 韩文杰 张辉 康朝阳 《激光技术》 北大核心 2025年第1期53-61,共9页
基于差频解算的调频连续波激光测距技术存在测量距离短、易受噪声干扰、受非线性调频影响大的问题。为了在相同机制条件下解决此问题,提出了基于匹配滤波的调频连续波激光测距方法,改进相干探测光路,加入信号反转单元和信号共轭单元,将... 基于差频解算的调频连续波激光测距技术存在测量距离短、易受噪声干扰、受非线性调频影响大的问题。为了在相同机制条件下解决此问题,提出了基于匹配滤波的调频连续波激光测距方法,改进相干探测光路,加入信号反转单元和信号共轭单元,将混频器换成卷积器,同时满足系统响应与发射波形匹配,并进行了相关仿真实验。结果表明,相比差频解算方法,匹配滤波方法可实现两倍于差频解算方法的测距范围,信噪比提高了9.5 dB,在非线性调频误差为19.8 MHz、198 MHz和396 MHz条件下均能得到较高分辨率的距离谱,表现出较好的抵抗非线性调频的能力。此研究可为该领域的科研工作者提供技术指导和新的思路。 展开更多
关键词 激光技术 调频连续波 匹配滤波 激光测距 信噪比 非线性
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