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Transforming Adolescent Smiles:Correcting Skeletal Mandibular Retrusion and Bimaxillary Protrusion with Clear Aligners
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作者 Wen-jie FAN Jia-qi ZHANG +2 位作者 Jia-qi ZHAN Li HU Li-li CHEN 《Current Medical Science》 SCIE CAS 2024年第3期657-666,共10页
Maxillary protrusion combined with mandibular retraction is a highly prevalent but extremely complex maxillofacial deformity that can have a serious negative impact on patients’facial aesthetics and mental health.The... Maxillary protrusion combined with mandibular retraction is a highly prevalent but extremely complex maxillofacial deformity that can have a serious negative impact on patients’facial aesthetics and mental health.The traditional orthodontic treatment strategy often involves extracting 4 first premolars and conventional fixed techniques,combined with mini-implant screws,to retract the anterior teeth and improve facial protrusion.In recent years,an invisible orthodontic technique,without brackets,has become increasingly popular.However,while an invisible aligner has been used in some cases with reasonable results,there remain significant challenges in achieving a perfect outcome.This case report presents an adolescent patient with bimaxillary protrusion and mandibular retrognathia.Based on the characteristics of the invisible aligners and the growth characteristics of the adolescent’s teeth and jawbone,we designed precise three-dimensional tooth movement and corresponding resistance/over-correction for each tooth,while utilizing the patient’s jawbone growth potential to promote rapid development of the mandible,accurately and efficiently correcting bimaxillary protrusion and skeletal mandibular retrognathia.The patient’s facial aesthetics,especially the lateral morphology,have been greatly improved,and various aesthetic indicators have also shown significant changes,and to the patient’s great benefit,invasive mini-implant screws were not used during the treatment.This case highlights the advantages of using invisible aligners in adolescent maxillary protrusion combined with mandibular retraction patients.Furthermore,comprehensive and accurate design combined with good application of growth potential can also enable invisible orthodontic technology to achieve perfect treatment effects in tooth extractions,providing clinical guidance for orthodontists. 展开更多
关键词 mandibular retrusion esthetic orthodontic treatment clear aligners growth potential
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Colour stabilities of three types of orthodontic clear aligners exposed to staining agents 被引量:5
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作者 Chen-Lu Liu Wen-Tian Sun +5 位作者 Wen Liao Wen-Xin Lu Qi-Wen Li Yunho Jeong Jun Liu Zhi-He Zhao 《International Journal of Oral Science》 SCIE CAS CSCD 2016年第4期246-253,共8页
The aim of this study was to evaluate and compare the colour stabilities of three types of orthodontic clear aligners exposed to staining agents in vitro. Sixty clear orthodontic aligners produced by three manufacture... The aim of this study was to evaluate and compare the colour stabilities of three types of orthodontic clear aligners exposed to staining agents in vitro. Sixty clear orthodontic aligners produced by three manufacturers (Invisalign, Angelalign, and Smartee) were immersed in three staining solutions (coffee, black tea, and red wine) and one control solution (distilled water). After 12-h and 7-day immersions, the aligners were washed in an ultrasonic cleaner and measured with a colourimeter. The colour changes (△E*) were calculated on the basis of the Commission Internationale de I'Eclairage L*a*b* colour system (CIE L*a*b*), and the results were then converted into National Bureau of Standards (NBS) units. Fourier transformation infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) were conducted to observe the molecular and morphologic alterations to the aligner surfaces, respectively. The three types of aligners exhibited slight colour changes after 12 h of staining, with the exception of the Invisalign aligners stained with coffee. The Invisalign aligners exhibited significantly higher AE* values (ranging from 0.30 to 27.81) than those of the Angelalign and Smartee aligners (AE* values ranging from 0.33 to 1.89 and 0.32 to 1.61, respectively, P〈O.05). IFT-IR analysis confirmed that the polymer-based structure of aligners did not exhibit significant chemical differences before and after the immersions. The SEM results revealed different surface alterations to the three types of aligner materials after the 7-day staining. The three types of aesthetic orthodontic appliances exhibited colour stability after the 12-h immersion, with the exception of the Invisalign aligners stained by coffee. The Invisalign aligners were more prone than the Angelalign and Smartee aligners to pigmentation. Aligner materials may be improved by considering aesthetic colour stability properties. 展开更多
关键词 AESTHETICS clear aligner clear aligner material colour stability orthodontic appliance
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ABBYY Aligner和Tmxmall对齐工具主要功能探究对比 被引量:3
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作者 万佳琦 肖飞 《英语广场(学术研究)》 2020年第25期27-29,共3页
计算机辅助翻译软件大大提高了翻译效率。本文试从用户角度,以对齐工具中的ABBYY Aligner独立式对齐工具和Tmxmall在线对齐工具为例,对这两种对齐工具的主要特性和功能进行对比和研究,以期帮助译员找到适合自己的、能满足用户个性化需... 计算机辅助翻译软件大大提高了翻译效率。本文试从用户角度,以对齐工具中的ABBYY Aligner独立式对齐工具和Tmxmall在线对齐工具为例,对这两种对齐工具的主要特性和功能进行对比和研究,以期帮助译员找到适合自己的、能满足用户个性化需求的对齐工具,从而提高翻译效率和准确率。 展开更多
关键词 计算机辅助翻译 ABBYY aligner Tmxmall在线对齐工具 语料对齐
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Highly Aligned Graphene Aerogels for Multifunctional Composites 被引量:1
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作者 Ying Wu Chao An +4 位作者 Yaru Guo Yangyang Zong Naisheng Jiang Qingbin Zheng Zhong‑Zhen Yu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第6期276-342,共67页
Stemming from the unique in-plane honeycomb lattice structure and the sp^(2)hybridized carbon atoms bonded by exceptionally strong carbon–carbon bonds,graphene exhibits remarkable anisotropic electrical,mechanical,an... Stemming from the unique in-plane honeycomb lattice structure and the sp^(2)hybridized carbon atoms bonded by exceptionally strong carbon–carbon bonds,graphene exhibits remarkable anisotropic electrical,mechanical,and thermal properties.To maximize the utilization of graphene’s in-plane properties,pre-constructed and aligned structures,such as oriented aerogels,films,and fibers,have been designed.The unique combination of aligned structure,high surface area,excellent electrical conductivity,mechanical stability,thermal conductivity,and porous nature of highly aligned graphene aerogels allows for tailored and enhanced performance in specific directions,enabling advancements in diverse fields.This review provides a comprehensive overview of recent advances in highly aligned graphene aerogels and their composites.It highlights the fabrication methods of aligned graphene aerogels and the optimization of alignment which can be estimated both qualitatively and quantitatively.The oriented scaffolds endow graphene aerogels and their composites with anisotropic properties,showing enhanced electrical,mechanical,and thermal properties along the alignment at the sacrifice of the perpendicular direction.This review showcases remarkable properties and applications of aligned graphene aerogels and their composites,such as their suitability for electronics,environmental applications,thermal management,and energy storage.Challenges and potential opportunities are proposed to offer new insights into prospects of this material. 展开更多
关键词 Highly aligned graphene aerogels Quantitative characterization of alignment Multifunctional composites Anisotropic properties Multifunctional applications
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BitmapAligner:Bit-Parallelism String Matching with MapReduce and Hadoop
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作者 Mary Aksa Junaid Rashid +3 位作者 Muhammad Wasif Nisar Toqeer Mahmood Hyuk-Yoon Kwon Amir Hussain 《Computers, Materials & Continua》 SCIE EI 2021年第9期3931-3946,共16页
Advancements in next-generation sequencer(NGS)platforms have improved NGS sequence data production and reduced the cost involved,which has resulted in the production of a large amount of genome data.The downstream ana... Advancements in next-generation sequencer(NGS)platforms have improved NGS sequence data production and reduced the cost involved,which has resulted in the production of a large amount of genome data.The downstream analysis of multiple associated sequences has become a bottleneck for the growing genomic data due to storage and space utilization issues in the domain of bioinformatics.The traditional string-matching algorithms are efficient for small sized data sequences and cannot process large amounts of data for downstream analysis.This study proposes a novel bit-parallelism algorithm called BitmapAligner to overcome the issues faced due to a large number of sequences and to improve the speed and quality of multiple sequence alignment(MSA).The input files(sequences)tested over BitmapAligner can be easily managed and organized using the Hadoop distributed file system.The proposed aligner converts the test file(the whole genome sequence)into binaries of an equal length of the sequence,line by line,before the sequence alignment processing.The Hadoop distributed file system splits the larger files into blocks,based on a defined block size,which is 128 MB by default.BitmapAligner can accurately process the sequence alignment using the bitmask approach on large-scale sequences after sorting the data.The experimental results indicate that BitmapAligner operates in real time,with a large number of sequences.Moreover,BitmapAligner achieves the exact start and end positions of the pattern sequence to test the MSA application in the whole genome query sequence.The MSA’s accuracy is verified by the bitmask indexing property of the bit-parallelism extended shifts(BXS)algorithm.The dynamic and exact approach of the BXS algorithm is implemented through the MapReduce function of Apache Hadoop.Conversely,the traditional seeds-and-extend approach faces the risk of errors while identifying the pattern sequences’positions.Moreover,the proposed model resolves the largescale data challenges that are covered through MapReduce in the Hadoop framework.Hive,Yarn,HBase,Cassandra,and many other pertinent flavors are to be used in the future for data structuring and annotations on the top layer of Hadoop since Hadoop is primarily used for data organization and handles text documents. 展开更多
关键词 Next-generation sequencing multiple sequence alignment MAPREDUCE HADOOP WHOLE-GENOME big data BIT-PARALLELISM
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Alignment Techniques in Total Knee Arthroplasty:Where do We Stand Today?
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作者 Hemanta Dhungana Subhash Jangid Meghal Goyal 《Chinese Medical Sciences Journal》 CAS CSCD 2024年第3期224-233,共10页
Achieving optimal alignment in total knee arthroplasty(TKA) is a critical factor in ensuring optimal outcomes and long-term implant survival. Traditionally, mechanical alignment has been favored to achieve neutral pos... Achieving optimal alignment in total knee arthroplasty(TKA) is a critical factor in ensuring optimal outcomes and long-term implant survival. Traditionally, mechanical alignment has been favored to achieve neutral postoperative joint alignment. However, contemporary approaches, such as kinematic alignments and hybrid techniques including adjusted mechanical, restricted kinematic, inverse kinematic, and functional alignments, are gaining attention for their ability to restore native joint kinematics and anatomical alignment, potentially leading to enhanced functional outcomes and greater patient satisfaction. The ongoing debate on optimal alignment strategies considers the following factors: long-term implant durability, functional improvement, and resolution of individual anatomical variations. Furthermore, advancements of computer-navigated and robotic-assisted surgery have augmented the precision in implant positioning and objective measurements of soft tissue balance. Despite ongoing debates on balancing implant longevity and functional outcomes, there is an increasing advocacy for personalized alignment strategies that are tailored to individual anatomical variations. This review evaluates the spectrum of various alignment techniques in TKA, including mechanical alignment, patient-specific kinematic approaches, and emerging hybrid methods. Each technique is scrutinized based on its fundamental principles, procedural techniques, inherent advantages, and potential limitations, while identifying significant clinical gaps that underscore the need for further investigation. 展开更多
关键词 total knee arthroplasty hybrid alignment functional alignment kinematic alignment alignment axes anatomical alignment mechanical alignment
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Joint alignment and steering to manage interference
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作者 Zhao Li Xiujuan Liang +2 位作者 Yinghou Liu Jia Liu Zheng Yan 《Digital Communications and Networks》 SCIE CSCD 2024年第2期429-438,共10页
In wireless communication networks,mobile users in overlapping areas may experience severe interference,therefore,designing effective Interference Management(IM)methods is crucial to improving network performance.Howe... In wireless communication networks,mobile users in overlapping areas may experience severe interference,therefore,designing effective Interference Management(IM)methods is crucial to improving network performance.However,when managing multiple disturbances from the same source,it may not be feasible to use existing IM methods such as Interference Alignment(IA)and Interference Steering(IS)exclusively.It is because with IA,the aligned interference becomes indistinguishable at its desired Receiver(Rx)under the cost constraint of Degrees-of-Freedom(DoF),while with IS,more transmit power will be consumed in the direct and repeated application of IS to each interference.To remedy these deficiencies,Interference Alignment Steering(IAS)is proposed by incorporating IA and IS and exploiting their advantages in IM.With IAS,the interfering Transmitter(Tx)first aligns one interference incurred by the transmission of one data stream to a one-dimensional subspace orthogonal to the desired transmission at the interfered Rx,and then the remaining interferences are treated as a whole and steered to the same subspace as the aligned interference.Moreover,two improved versions of IAS,i.e.,IAS with Full Adjustment at the Interfering Tx(IAS-FAIT)and Interference Steering and Alignment(ISA),are presented.The former considers the influence of IA on the interfering user-pair's performance.The orthogonality between the desired signals at the interfered Rx can be maintained by adjusting the spatial characteristics of all interferences and the aligned interference components,thus ensuring the Spectral Efficiency(SE)of the interfering communication pairs.Under ISA,the power cost for IS at the interfered Tx is minimized,hence improving SE performance of the interfered communication-pairs.Since the proposed methods are realized at the interfering and interfered Txs cooperatively,the expenses of IM are shared by both communication-pairs.Our in-depth simulation results show that joint use of IA and IS can effectively manage multiple disturbances from the same source and improve the system's SE. 展开更多
关键词 INTERFERENCE Interference management Interference alignment Interference steering Spectral efficiency
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Improved spatio-temporal alignment measurement method for hull deformation
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作者 XU Dongsheng YU Yuanjin +1 位作者 ZHANG Xiaoli PENG Xiafu 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第2期485-494,共10页
In this paper,an improved spatio-temporal alignment measurement method is presented to address the inertial matching measurement of hull deformation under the coexistence of time delay and large misalignment angle.Lar... In this paper,an improved spatio-temporal alignment measurement method is presented to address the inertial matching measurement of hull deformation under the coexistence of time delay and large misalignment angle.Large misalignment angle and time delay often occur simultaneously and bring great challenges to the accurate measurement of hull deformation in space and time.The proposed method utilizes coarse alignment with large misalignment angle and time delay estimation of inertial measurement unit modeling to establish a brand-new spatiotemporal aligned hull deformation measurement model.In addition,two-step loop control is designed to ensure the accurate description of dynamic deformation angle and static deformation angle by the time-space alignment method of hull deformation.The experiments illustrate that the proposed method can effectively measure the hull deformation angle when time delay and large misalignment angle coexist. 展开更多
关键词 inertial measurement spatio-temporal alignment hull deformation
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Beam based alignment using a neural network
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作者 Guan-Liang Wang Ke-Min Chen +5 位作者 Si-Wei Wang Zhe Wang Tao He Masahito Hosaka Guang-Yao Feng Wei Xu 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第4期108-118,共11页
Beams typically do not travel through the magnet centers because of errors in storage rings.The beam deviating from the quadrupole centers is affected by additional dipole fields due to magnetic field feed-down.Beam-b... Beams typically do not travel through the magnet centers because of errors in storage rings.The beam deviating from the quadrupole centers is affected by additional dipole fields due to magnetic field feed-down.Beam-based alignment(BBA)is often performed to determine a golden orbit where the beam circulates around the quadrupole center axes.For storage rings with many quadrupoles,the conventional BBA procedure is time-consuming,particularly in the commissioning phase,because of the necessary iterative process.In addition,the conventional BBA method can be affected by strong coupling and the nonlinearity of the storage ring optics.In this study,a novel method based on a neural network was proposed to determine the golden orbit in a much shorter time with reasonable accuracy.This golden orbit can be used directly for operation or adopted as a starting point for conventional BBA.The method was demonstrated in the HLS-II storage ring for the first time through simulations and online experiments.The results of the experiments showed that the golden orbit obtained using this new method was consistent with that obtained using the conventional BBA.The development of this new method and the corresponding experiments are reported in this paper. 展开更多
关键词 Golden orbit Beam-based alignment Neural network Storage ring
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A Time Series Short-Term Prediction Method Based on Multi-Granularity Event Matching and Alignment
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作者 Haibo Li Yongbo Yu +1 位作者 Zhenbo Zhao Xiaokang Tang 《Computers, Materials & Continua》 SCIE EI 2024年第1期653-676,共24页
Accurate forecasting of time series is crucial across various domains.Many prediction tasks rely on effectively segmenting,matching,and time series data alignment.For instance,regardless of time series with the same g... Accurate forecasting of time series is crucial across various domains.Many prediction tasks rely on effectively segmenting,matching,and time series data alignment.For instance,regardless of time series with the same granularity,segmenting them into different granularity events can effectively mitigate the impact of varying time scales on prediction accuracy.However,these events of varying granularity frequently intersect with each other,which may possess unequal durations.Even minor differences can result in significant errors when matching time series with future trends.Besides,directly using matched events but unaligned events as state vectors in machine learning-based prediction models can lead to insufficient prediction accuracy.Therefore,this paper proposes a short-term forecasting method for time series based on a multi-granularity event,MGE-SP(multi-granularity event-based short-termprediction).First,amethodological framework for MGE-SP established guides the implementation steps.The framework consists of three key steps,including multi-granularity event matching based on the LTF(latest time first)strategy,multi-granularity event alignment using a piecewise aggregate approximation based on the compression ratio,and a short-term prediction model based on XGBoost.The data from a nationwide online car-hailing service in China ensures the method’s reliability.The average RMSE(root mean square error)and MAE(mean absolute error)of the proposed method are 3.204 and 2.360,lower than the respective values of 4.056 and 3.101 obtained using theARIMA(autoregressive integratedmoving average)method,as well as the values of 4.278 and 2.994 obtained using k-means-SVR(support vector regression)method.The other experiment is conducted on stock data froma public data set.The proposed method achieved an average RMSE and MAE of 0.836 and 0.696,lower than the respective values of 1.019 and 0.844 obtained using the ARIMA method,as well as the values of 1.350 and 1.172 obtained using the k-means-SVR method. 展开更多
关键词 Time series short-term prediction multi-granularity event alignMENT event matching
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Paving continuous heat dissipation pathways for quantum dots in polymer with orangeinspired radially aligned UHMWPE fibers
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作者 Xuan Yang Xinfeng Zhang +3 位作者 Tianxu Zhang Linyi Xiang Bin Xie Xiaobing Luo 《Opto-Electronic Advances》 SCIE EI CAS CSCD 2024年第7期27-38,共12页
Thermal management of nanoscale quantum dots(QDs)in light-emitting devices is a long-lasting challenge.The existing heat transfer reinforcement solutions for QDs-polymer composite mainly rely on thermal-conductive fil... Thermal management of nanoscale quantum dots(QDs)in light-emitting devices is a long-lasting challenge.The existing heat transfer reinforcement solutions for QDs-polymer composite mainly rely on thermal-conductive fillers.However,this strategy failed to deliver the QDs’heat generation across a long distance,and the accumulated heat still causes considerable temperature rise of QDs-polymer composite,which eventually menaces the performance and reliability of lightemitting devices.Inspired by the radially aligned fruit fibers in oranges,we proposed to eliminate this heat dissipation challenge by establishing long-range ordered heat transfer pathways within the QDs-polymer composite.Ultrahigh molecular weight polyethylene fibers(UPEF)were radially aligned throughout the polymer matrix,thus facilitating massive efficient heat dissipation of the QDs.Under a UPEF filling fraction of 24.46 vol%,the in-plane thermal conductivity of QDs-radially aligned UPEF composite(QDs-RAPE)could reach 10.45 W m^(−1) K^(−1),which is the highest value of QDs-polymer composite reported so far.As a proof of concept,the QDs’working temperature can be reduced by 342.5℃ when illuminated by a highly concentrated laser diode(LD)under driving current of 1000 mA,thus improving their optical performance.This work may pave a new way for next generation high-power QDs lighting applications. 展开更多
关键词 quantum dots UHMWPE fibers radial alignment heat dissipation light-emitting devices
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P-and SV-wave dispersion and attenuation in saturated microcracked porous rock with aligned penny-shaped fractures
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作者 Sheng-Qing Li Wen-Hao Wang +2 位作者 Yuan-Da Su Jun-Xin Guo Xiao-Ming Tang 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期143-161,共19页
P-and SV-wave dispersion and attenuation have been extensively investigated in saturated poroelastic media with aligned fractures.However,there are few existing models that incorporate the multiple wave attenuation me... P-and SV-wave dispersion and attenuation have been extensively investigated in saturated poroelastic media with aligned fractures.However,there are few existing models that incorporate the multiple wave attenuation mechanisms from the microscopic scale to the macroscopic scale.Hence,in this work,we developed a unified model to incorporate the wave attenuation mechanisms at different scales,which includes the microscopic squirt flow between the microcracks and pores,the mesoscopic wave-induced fluid flow between fractures and background(FB-WIFF),and the macroscopic Biot's global flow and elastic scattering(ES)from the fractures.Using Tang's modified Biot's theory and the mixed-boundary conditions,we derived the exact frequency-dependent solutions of the scattering problem for a single penny-shaped fracture with oblique incident P-and SV-waves.We then developed theoretical models for a set of aligned fractures and randomly oriented fractures using the Foldy approximation.The results indicated that microcrack squirt flow considerably influences the dispersion and attenuation of P-and SV-wave velocities.The coupling effects of microcrack squirt flow with the FB-WIFF and ES of fractures cause much higher velocity dispersion and attenuation for P waves than for SV waves.Randomly oriented fractures substantially reduce the attenuation caused by the FB-WIFF and ES,particularly for the ES attenuation of SV waves.Through a comparison with existing models in the limiting cases and previous experimental measurements,we validated our model. 展开更多
关键词 aligned fractures P-and SV-wave Dispersion and attenuation Microcracked porous background FB-WIFF Elastic scattering Squirt flow
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A Study on Aligning Nursing Curriculum with Hospital Clinical Competency Requirements
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作者 Xuemei Li Jarrent Tayag 《Journal of Contemporary Educational Research》 2024年第9期283-289,共7页
The purpose of this study is to coordinate the alignment between the nursing curriculum and hospital clinical competencies,identify the reasons for the gaps,evaluate the impact of these gaps on the nursing profession,... The purpose of this study is to coordinate the alignment between the nursing curriculum and hospital clinical competencies,identify the reasons for the gaps,evaluate the impact of these gaps on the nursing profession,and propose strategies to bridge these gaps.This study will help strengthen nursing education,improve nursing students’skills,and help students adapt to complex clinical environments. 展开更多
关键词 Nursing education Clinical competency Hospital requirements Curriculum alignment Gap analysis
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On The Cauchy Problem for A 1D Euler-Alignment System in Besov Spaces
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作者 Yaojun Yang 《Journal of Applied Mathematics and Physics》 2024年第2期603-631,共29页
In this paper, we investigate a 1D pressureless Euler-alignment system with a non-local alignment term, describing a kind of self-organizing problem for flocking. As a result, by the transport equation theory and Lagr... In this paper, we investigate a 1D pressureless Euler-alignment system with a non-local alignment term, describing a kind of self-organizing problem for flocking. As a result, by the transport equation theory and Lagrange coordinate transformation, the local well-posedness of the solutions for the 1D pressureless Euler-alignment in Besov spaces  with 1≤p∞ is established. Next, the ill-posedness of the solutions for this model in Besov spaces  with 1≤p and  is also deduced. Finally, the precise blow-up criteria of the solutions for this system is presented in Besov spaces  with 1≤p . 展开更多
关键词 Euler-alignment Equations Local Well-Posedness Blow-Up Criteria ILL-POSEDNESS
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Initial Alignment Technique for SINS of Vehicles in the Moving State 被引量:17
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作者 缪玲娟 沈军 +1 位作者 刘伟 杨勇 《Journal of Beijing Institute of Technology》 EI CAS 2002年第3期234-239,共6页
An initial alignment technique for the strapdown inertial navigation system (SINS) of vehicles in the moving state is researched. By selecting an odometer as the system’s external sensor, the mathematical model for t... An initial alignment technique for the strapdown inertial navigation system (SINS) of vehicles in the moving state is researched. By selecting an odometer as the system’s external sensor, the mathematical model for the alignment in the moving state is established and the observability of the system is analyzed. The results show that the SINS can successfully achieve the precision alignment in 10 min when the vehicle is moving toward the prearranged place after its staying for several seconds to perform the coarse alignment. The precision of alignment can also be improved in the moving state compared with that in the static state. 展开更多
关键词 strapdown inertial navigation system initial alignment Kalman filter
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由一般拓扑度量空间所产生的Alignment空间 被引量:5
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作者 卢国祥 沈世镒 《工程数学学报》 CSCD 北大核心 2008年第6期1097-1101,共5页
Alignment空间是一个在广义误差下定义的度量空间。在以往的信息处理问题中,一般只讨论离散状态下的序列比对Alignment问题,并由此产生一种新的非线性度量空间-Alignment空间。本文将离散状态下的Alignment空间推广到一般情况,得到了由... Alignment空间是一个在广义误差下定义的度量空间。在以往的信息处理问题中,一般只讨论离散状态下的序列比对Alignment问题,并由此产生一种新的非线性度量空间-Alignment空间。本文将离散状态下的Alignment空间推广到一般情况,得到了由一般拓扑度量空间所产生的Alignment空间仍然是度量空间,并证明了Alignment距离与Levenshtein距离的等价性。 展开更多
关键词 由度量空间产生的alignment空间 度量空间的基本定理 alignment距离 Levenshtein距离
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导航辅助全膝关节置换应用功能学对线恢复患者固有生理力线和关节线倾角
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作者 王熠军 郑恺 +5 位作者 张连方 朱锋 张韦成 李荣群 周军 徐耀增 《中国组织工程研究》 CAS 北大核心 2025年第27期5810-5818,共9页
背景:机械轴对线是全膝关节置换术中的“金标准”对线技术,但是无论假体材料和导航机器人辅助技术如何发展,应用机械轴对线的全膝关节置换后仍存在20%左右的患者不满意率。目的:探讨导航辅助全膝关节置换过程中应用功能学对线的早期疗... 背景:机械轴对线是全膝关节置换术中的“金标准”对线技术,但是无论假体材料和导航机器人辅助技术如何发展,应用机械轴对线的全膝关节置换后仍存在20%左右的患者不满意率。目的:探讨导航辅助全膝关节置换过程中应用功能学对线的早期疗效。方法:回顾性分析2019年10月至2023年6月连续44例(50膝)行计算机导航辅助全膝关节置换术中应用功能学对线的患者资料,男12例(14膝),女32例(36膝);选择同期同一手术团队行导航辅助全膝关节置换术中应用机械轴对线的46例(50膝)连续病例作为对照,男5例(5膝),女41例(45膝)。观察两组顾患者胫骨侧截骨角度、胫骨平台截骨量、股骨侧截骨角度、股骨远端、后方及前方截骨量、关节线移动情况;对比术前、术后屈曲和伸直间隙内外侧松弛度、髋-膝-踝角、股骨远端机械轴外侧角、胫骨近端机械轴内侧角、关节汇聚角、矢状面股骨组件角、胫骨后倾角、算术髋-膝-踝角、关节线倾角、膝关节冠状面力线分型、西安大略和麦克马斯特大学骨关节炎指数、美国特种外科医院评分及膝关节遗忘评分。结果与结论:①功能学对线组术中胫骨平台截骨角度大于机械轴对线组,间隙不平衡比例(2%)小于机械轴对线组(18%),差异均有显著性意义(P<0.05);②术后功能学对线组髋-膝-踝角、胫骨近端机械轴内侧角、算术髋-膝-踝角、关节线倾角小于机械轴对线组,差异均有显著性意义(P<0.05);③术前最常见的膝关节冠状面力线分型是Ⅰ型(功能学对线组80%,机械轴对线组42%);④术后功能学对线组关节线倾角<177°比例为44%,大于机械轴对线组的14%;⑤功能学对线组术后1,6个月及末次随访美国特种外科医院评分高于机械轴对线组,差异均有显著性意义(P<0.05);功能学对线组术后1个月西安大略和麦克马斯特大学骨关节炎指数低于机械轴对线组,差异有显著性意义(t=-2.85,P=0.005);两组术后膝关节活动度及膝关节遗忘评分相比差异均无显著性意义(P>0.05);⑥提示导航辅助全膝关节置换应用功能学对线能够优化早期临床疗效;与机械轴对线相比,功能学对线在恢复患者固有生理力线和关节线倾角、避免软组织松解方面更具优势。 展开更多
关键词 全膝关节置换 功能学对线 机械轴对线 外科手术 计算机辅助 对比研究 骨科植入物
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不同厚度及刚性隐形矫治器内收上颌前牙的有限元分析
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作者 杨天梅 王婧 +2 位作者 马福娟 张俭 葛振林 《中国组织工程研究》 CAS 北大核心 2025年第22期4671-4678,共8页
背景:隐形矫治器因其特殊的材料性能,在拔除上颌第一前磨牙内收前牙关闭间隙过程中更易发生“过山车效应”,牙齿倾斜移动,导致前牙覆牙合加深、后牙开牙合。是否可以通过改变矫治器厚度或刚性减轻“过山车效应”,更好地控制正畸牙移动,... 背景:隐形矫治器因其特殊的材料性能,在拔除上颌第一前磨牙内收前牙关闭间隙过程中更易发生“过山车效应”,牙齿倾斜移动,导致前牙覆牙合加深、后牙开牙合。是否可以通过改变矫治器厚度或刚性减轻“过山车效应”,更好地控制正畸牙移动,目前相关研究较少。目的:通过三维有限元分析不同厚度及刚性隐形矫治器内收上颌前牙时控制牙齿移动能力方面的差异。方法:将侧貌凸患者的锥形束CT数据导入Mimics等软件,模拟临床病例,构建去除第一前磨牙后包括上颌骨、牙齿、牙周膜的三维有限元模型,装配0.50,0.75 mm 2种厚度膜片的隐形矫治器,通过软件加载1000,2000 MPa 2种弹性模量的材料属性,总共构建4组模型工况。按照临床矫治方案设计关闭拔牙间隙,在Workbench 2023 R1软件中加载并计算,分析牙周膜应力分布、牙齿位移趋势及牙齿初始位移量。结果与结论:(1)4种模型工况下的牙周膜Von-Mises应力分布规律一致,牙周膜最大等效应力主要分布在牙颈部,并且矫治器膜片越厚牙周膜Von-Mises应力越大、矫治器膜片弹性模量越大牙周膜Von-Mises应力越大;(2)4种模型工况下的上颌牙列整体位移趋势为前牙冠舌向、根唇向的移动,后牙冠近中移动、根远中移动,牙齿的冠、根位移方向均相反,牙冠位移量大于牙根位移量;除尖牙外,其余牙齿均呈现矫治器膜片越厚R/C值(牙根移动量与冠移动量比值)越小、矫治器膜片弹性模量越大R/C值越小的趋势;(3)结果表明,利用隐形矫治器内收上颌前牙时,在不设计切牙转矩补偿的情况下牙齿表现为倾斜移动趋势,矫治器厚度和弹性模量越大时对牙齿控的制能力越强,牙齿倾斜移动趋势减小;尖牙则需通过其他辅助手段进行控制。 展开更多
关键词 隐形矫治器 内收前牙 弹性模量 膜片厚度 有限元分析 生物力学
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Ground Alignment of Inertial Navigation System with the Aid of GPS Signals 被引量:2
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作者 冯绍军 胡国辉 袁信 《Journal of Southeast University(English Edition)》 EI CAS 1998年第2期81-85,共5页
Due to the poor observability of INS ground self alignment, only horizontal alignment is satisfied. This paper proposes using GPS double difference carrier phase as external reference to improve the observability of ... Due to the poor observability of INS ground self alignment, only horizontal alignment is satisfied. This paper proposes using GPS double difference carrier phase as external reference to improve the observability of INS self alignment. Through observability analysis and computer simulation, it is demonstrated that the azimuth alignment is as quick as horizontal alignment, the accuracy of horizontal alignment is improved, and the gyros errors can be estimated quickly and precisely. 展开更多
关键词 inertial navigation system alignMENT OBSERVABILITY GPS carrier phase
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Ultra-precision alignment technique based on modified Moiré signals 被引量:2
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作者 张金龙 陈从颜 +1 位作者 余玲玲 刘京南 《Journal of Southeast University(English Edition)》 EI CAS 2005年第1期16-19,共4页
A novel method for automatic ultra-precision alignment is presented.This method relies on the modified Moiré technique,and alignment marks are used in the form of gratings.The modified Moiré technique can ef... A novel method for automatic ultra-precision alignment is presented.This method relies on the modified Moiré technique,and alignment marks are used in the form of gratings.The modified Moiré technique can effectively improve detecting sensitivity of signals and simplify the control system by using only one pair of laser-Moiré sensors.We present the mathematical model and simulation results of diffracting two gratings.The effect of various parameters on Moiré signals is studied theoretically and experimentally,and the results are found to be consistent.A computer controlled alignment device using one pair of Moiré sensors is designed.The device can achieve a fully automatic precision alignment by the modified Moiré signal.The experimental result shows that the alignment device can obtain the resolution of 5 nm and the positioning accuracy of ±0 5 μm. 展开更多
关键词 Moiré signal ultra-precision alignment modified Moiré technique automatic control
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