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Cool white light and tunable multicolor emission from Tb^(3+)/Dy^(3+)co-activated glasses under different excitations for WlEDs

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Journal of Rare Earths 2024年第1期42卷 46-56,I0002页

作者： l.Vijayalakshmi K.Naveen Kumar Jong Dae Baek Department of Automotive Engineering Yeungnam UniversityGyeongsanGyeongbuk38541Republic of Korea Department of Mechanical Engineering Yeungnam UniversityGyeongsan38541Republic of Korea

A set of co-doped(Tb^(3+)/Dy^(3+))lithium zinc borate(lZB)glasses were developed by melt *** structural evaluation was performed for synthesized glassy *** Dy^(3+)and Tb^(3+)individually doped glasses exhibit intense yellow and green luminescence bands at 575 nm(^(4)F_(9/2)→^(6)H_(13/2))and543 nm(^(5)D_(4)→^(7)F_(5)),*** sensitization effect of Dy^(3+)on Tb^(3+)was analyzed by increasing the Tb^(3+)content with respect to the optimum Dy^(3+)content(0.5 mol%)in Dy^(3+)/Tb^(3+).The spectral overlay of Dy^(3+)luminescence and Tb^(3+)absorption profiles,Dy^(3+)/Tb^(3+)Pl spectra under different excitations 352,362,376,and 385 nm,shortening decay lifetimes of Dy^(3+)in Dy^(3+)/Tb^(3+)co-activated glasses,energy transfer(ET)parameters,chromaticity coordinates and their corresponding correlated temperatures all help to explain ET from Dy^(3+)to Tb^(3+).At 385 nm of Dy^(3+)excitation,the optimized co-activated(0.5Dy^(3+)+1.0Tb^(3+)):lZB glass displays cool white light *** non-radiative ET from Dy^(3+)to Tb^(3+)is dominated by electric dipole-dipole interaction and its ET efficiency was calculated to be 63%.At the same time,reverse ET from Tb^(3+)to Dy^(3+)was also *** shift in color coordinates from dominant yellow to greenish-yellow,green and white light emission suggests that Dy^(3+)/Tb^(3+)coactivated lZB glasses can be a potential candidate for UV converted multicolor and white light emitting devices.

关键词： Rare earths Photoluminescence Energy transfer Spectral overlap Decay lifetime Multicolor emitting lEDs

Chronic active and atrophic gastritis as significant contributing factor to the development of gastric cystica profunda

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World Journal of Gastroenterology 2024年第17期30卷 2308-2310页

作者： Veronika Papp Pál Miheller Department of Surgery Transplantation and GastroenterologySemmelweis UniversityBudapest 1082Hungary

Gastric cystica profunda(GCP)is an uncommon but underestimated gastric *** precancerous potential determines its *** addition to previous mucosa injury due to operations,biopsy or polypectomy,chronic active and atrophic gastritis may also lead to the development of *** carefully examining the stomach and taking biopsy samples from the susceptible regions,the stage of atrophy can be *** atrophic gastritis is a risk factor for cancer evolvement and it can also contribute to GCPs *** frequently occur close to early gastric cancers(EGCs)or EGC can arise from the cystic *** resection is an effective and minimally invasive treat-ment in GCP.

关键词： Gastric cystica profunda Chronic active gastritis Atrophic gastritis Operative link for Gastritis Assessment staging Early gastric cancer Endoscopic resection

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基于动力学模型的手术器械夹持力估计研究

机械传动 2024年第4期48卷 44-50页

作者：刘芬刘佳豪贠今天桑宏强天津工业大学机械工程学院天津300387 天津市现代机电装备技术重点实验室天津300387

手术器械夹持力估计问题一直是微创手术机器人手术器械研究的重点。在微创手术过程中,夹持力过大会造成组织损伤,夹持力过小会使缝合针等脱落,引发危险。因此,研究如何估计手术器械夹持力是非常有必要的。根据手术器械的结构特点,提出... 详细信息

手术器械夹持力估计问题一直是微创手术机器人手术器械研究的重点。在微创手术过程中,夹持力过大会造成组织损伤,夹持力过小会使缝合针等脱落,引发危险。因此,研究如何估计手术器械夹持力是非常有必要的。根据手术器械的结构特点,提出了一种基于动力学模型的夹持力估计方法。建立的模型考虑了手术器械动力学模型、丝传动系统力和位移传递特性和直流电动机特性,得到了手术器械电动机电流和夹持力之间的关系;通过Matlab对夹持力模型进行仿真验证,得到了手术器械末端执行器随电动机电流变化的夹持力变化曲线。仿真结果表明,基于动力学模型的手术器械夹持力估计模型与实际情况相符,为后续的手术器械夹持力安全保障研究提供了理论依据。

关键词：手术器械动力学模型丝传动夹持力

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动水头作用下花岗岩风化土的内部侵蚀机理

水土保持通报 2024年第2期44卷 80-90页

作者：王浩严耿明李传东豆红强福州大学紫金地质与矿业学院福建福州350108 福州大学土木工程学院福建福州350108

[目的]揭示动水头作用下花岗岩风化土侵蚀演化的动态过程,研究动态水力条件对土体内部侵蚀发展的影响,探明颗粒迁移规律与内部侵蚀机理,为深入研究花岗岩边坡的破坏模式与促滑机理提供理论依据。[方法]设计竖向土柱渗流装置,开展上升水... 详细信息

[目的]揭示动水头作用下花岗岩风化土侵蚀演化的动态过程,研究动态水力条件对土体内部侵蚀发展的影响,探明颗粒迁移规律与内部侵蚀机理,为深入研究花岗岩边坡的破坏模式与促滑机理提供理论依据。[方法]设计竖向土柱渗流装置,开展上升水头与正弦水头条件下花岗岩风化土柱的渗流试验,基于渗流土柱顶面与侧面的试验现象,从渗流速度变化、颗粒流失量变化和渗流前后颗粒级配、质量变化等方面,分析动水头作用下花岗岩风化土内部侵蚀的发育特征。[结果]①花岗岩风化土粒径差异较大,在骨架间存在微小孔隙,渗流冲刷作用使得土颗粒通过土体骨架间的孔隙运移流失。在内部侵蚀过程中,细颗粒流失量相对较多,粗颗粒流失量较少。②土体内部侵蚀作用是渐进发展的过程,在土体薄弱区域的结构最先产生变形与破坏。试验中渗流泉眼由土柱边界开始发展到土柱中部区域,渗流通道沿着渗流方向自下而上发育,水力条件短时间内发生显著变化会造成渗流通道快速贯通。③土体内部侵蚀作用将随渗流时间推进而趋于稳定,但正弦水头将“激活”土颗粒运动,加剧土体的内部侵蚀作用。加大水头变化幅度或减小水头变化周期,能够加剧土体内部侵蚀作用,导致水流运移速度加快以及颗粒迁移流失量增多。[结论]水力条件变化对土体内部侵蚀作用存在显著影响,正弦水头更能加剧颗粒迁移流失。

关键词：模型试验花岗岩风化土动水头内部侵蚀

Time trends and outcomes of gastrostomy placement in a Swedish national cohort over two decades

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World Journal of Gastroenterology 2024年第10期30卷 1358-1367页

作者： Martin löfling Skogar Magnus Sundbom Department of Surgical Sciences Uppsala UniversityUppsala 75185Sweden

BACKGROUND Percutaneous endoscopic gastrostomy(PEG)and laparoscopically inserted gastrostomy have become the gold standard for adult patients and children,respectively,requiring long-term enteral nutrition ***-related mortality is a rare event,often reported to be zero in smaller *** data on 30-d mortality and long-term survival rates after gastrostomy placement are scarce in the *** To study the use of gastrostomies in Sweden from 1998-2019 and to analyze procedure-related mortality and short-term(long-term *** In this retrospective,population-based cohort study,individuals that had received a gastrostomy between 1998-2019 in Sweden were *** were identified in the Swedish National Patient Register,and survival analysis was possible by cross-referencing the Swedish Death *** cohort was divided into three age groups:Children(0-18 years);adults(19-64 years);and elderly(≥65 years).Kaplan-Meier with log-rank test and Cox regression were used for survival *** In total 48682 individuals(52%males,average age 60.9±25.3 years)were *** cohort consisted of 12.0%children,29.5%adults,and 58.5%*** increased use of gastrostomies was observed during the study period,from 13.7/100000 to 22.3/100000 individuals(Pled(about 800 to 1800/year),with a corresponding decrease in open gastrostomy(about 700 to 340/year).laparoscopic gastrostomy increased more than ten-fold(about 20 to 240/year).Overall,PEG,open gastrostomy,and laparoscopic gastrostomy constituted 70.0%(n=34060),23.3%(n=11336),and 4.9%(n=2404),***-related mortality was 0.1%(n=44)overall(PEG:0.05%,open:0.24%,laparoscopic:0.04%).The overall 30-d mortality rate was 10.0%(PEG:9.8%,open:12.4%,laparoscopic:1.7%)and decreased from 11.6%in 1998-2009 vs 8.5%in 2010-2019(Pl rates for children,adults,and elderly were 93.7%,67.5%,a

关键词： Gastrostomy Percutaneous endoscopic gastrostomy Dysphagia Enteral nutrition long-term Survival Complication

Distributed swarm control for multi-robot systems inspired by shepherding behaviors

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Science China(Technological Sciences) 2024年第7期67卷 2191-2202页

作者： SUN GuiBin GU HaiBo lÜJinHu School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Zhongguancun laboratory Beijing 100094China

Swarming behaviors play an eminent role in both biological and engineering research, and show great potential applications in many emerging fields. Traditional swarming models still lack integrity, uniformity, and stability in swarm forming processes,resulting in fragmentation and void phenomena. Inspired by the shepherding behaviors observed in nature, we propose an integrated negotiation-control scheme for distributed swarm control of massive robots. The core idea of this scheme is that the robots at the boundary of the group herd the internal robots to form an equilibrium swarm. For this purpose, we introduce a concept of virtual group center towards which boundary robots herd internal robots. Then, a distributed negotiation mechanism is designed to allow each robot to negotiate the virtual group center only through local interactions with its neighbors. After that, we propose a shepherding-inspired swarm control law to drive a group of robots to form an integrated, uniform, and stable configuration from any initial states. Both numerical and flight simulations are presented to verify the effectiveness of our proposed swarm control scheme.

关键词： swarm control multi-robot system negotiation-control scheme shepherding behavior

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Tomographic reconstruction of the Earth’s magnetosheath from multiple spacecraft:a theoretical study

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Earth and Planetary Physics 2024年第1期8卷 204-214页

作者： A.M.Jorgensen TianRan Sun Y.Huang l.li R.Xu l.Dai Chi Wang New Mexico Institute of Mining and Technology SocorroNMUSA National Space Science Center Chinese Academy of SciencesBeijing 100190China Tsinghua University Beijing 100084China

Following our earlier work on tomographic reconstruction of the magnetosheath soft X-ray emissions with superposed epoch analysis of many images recorded from a single spacecraft we now explore the instantaneous reconstruction of the magnetosheath and magnetopause using a few images recorded simultaneously from a few *** work is motivated by the prospect of possibly having two or three soft X-ray imagers in space in the coming years,and that many phenomena which occur at the magnetopause boundary,such as reconnection events and pressure pulse responses,do not lend themselves as well to superposed epoch *** the reconstruction is successful-which we demonstrate in this paper that it can be-this collection of imagers can be used to reconstruct the magnetosheath and magnetopause from a single image from each spacecraft,allowing for high time resolution *** this paper we explore the reconstruction using,two,three,and four *** show that the location of the subsolar point of the magnetopause can be determined with just two satellites,and that volume emissions of soft X-rays,and the shape of the boundary,can be reconstructed using three or more satellites.

关键词： magnetosheath tomography soft X-ray imaging SMIlE

Experimental implementation of phase triplicator gratings in a spatial light modulator

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Chinese Optics letters 2024年第2期22卷 64-69页

作者：高尚 María del Mar Sánchez-lópez Ignacio Moreno Instituto de Bioingeniería Universidad Miguel HernándezElche 03202Spain Departamento de Física Aplicada Universidad Miguel HernándezElche 03202Spain Departamento de Ciencia de Materiales Óptica y Tec.Electr´onicaUniversidad Miguel HernándezElche 03202Spain

In this work,we compare different methods for implementing a triplicator,a phase grating that generates three equiintense diffraction *** design with optimal efficiency features a continuous phase profile,which cannot be easily reproduced,and is typically affected by *** compare its performance with binary and sinusoidal phase *** also analyze the effect of quantizing the phase ***,a random approach is adopted to eliminate the additional harmonic *** all cases,a liquid-crystal-on-silicon spatial light modulator is employed to experimentally verify and compare the different approaches.

关键词： diffraction gratings phase modulation triplicator spatial light modulators

Stability and performance analysis of the compressed Kalman filter algorithm for sparse stochastic systems

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Science China(Technological Sciences) 2024年第2期67卷 380-394页

作者： lI RongJiang GAN Die XIE SiYu lüJinHu Key laboratory of Systems and Control Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China Zhongguancun laboratory Beijing 100049China School of Aeronautics and Astronautics University of Electronic Science and Technology of ChinaChengdu 611731China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

This paper considers the problem of estimating unknown sparse time-varying signals for stochastic dynamic *** deal with the challenges of extensive sparsity,we resort to the compressed sensing method and propose a compressed Kalman filter(KF)*** algorithm first compresses the original high-dimensional sparse regression vector via the sensing matrix and then obtains a KF estimate in the compressed low-dimensional ***,the original high-dimensional sparse signals can be well recovered by a reconstruction *** ensure stability and establish upper bounds on the estimation errors,we introduce a compressed excitation condition without imposing independence or stationarity on the system signal,and therefore suitable for feedback *** further present the performance of the compressed KF ***,we show that the mean square compressed tracking error matrix can be approximately calculated by a linear deterministic difference matrix equation,which can be readily evaluated,analyzed,and ***,a numerical example demonstrates that our algorithm outperforms the standard uncompressed KF algorithm and other compressed algorithms for estimating high-dimensional sparse signals.

关键词： sparse signal compressed sensing Kalman filter algorithm compressed excitation condition stochastic stability tracking performance