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Aperture shape optimization in intensity-modulated radiation therapy planning

Nuclear Science and Techniques 2023年第9期34卷 106-117页

作者： Li-Yuan zhang Zhi-Guo Gui Peng-cheng zhang Jie yang Shanxi Provincial Key Laboratory for Biomedical Imaging and Big Data North University of ChinaTaiyuan 030051China School of Medicine Management Shanxi University of Chinese MedicineTaiyuan 030619China

The gradient element of the aperture gradient map is utilized directly to generate the aperture shape without *** process can be likened to choosing the direction of negative gradient descent for the generic aperture shape *** negative gradient descent direction is more suitable under local conditions and has a slow convergence *** overcome these limitations,this study introduced conjugate gradients into aperture shape optimization based on gradient ***,the aperture gradient map of the current beam was obtained for the proposed aperture shape optimiza-tion method,and the gradients of the aperture gradient map were modulated using conjugate gradients to form a modulated gradient *** aperture shape was generated based on the modulated gradient *** proposed optimization method does not change the optimal solution of the original optimization problem,but changes the iterative search direction when generating the aperture *** performance of the proposed method was verified using cases of head and neck cancer,and prostate *** optimization results indicate that the proposed optimization method better protects the organs at risk and rapidly reduces the objective function value by ensuring a similar dose distribution to the planning target *** to the contrasting methods,the normal tissue complication probability obtained by the proposed optimization method decreased by up to 4.61%,and the optimization time of the proposed method decreased by 5.26%on average for ten cancer *** effectiveness and acceleration of the proposed method were verified through comparative *** to the comparative experiments,the results indicate that the proposed optimization method is more suitable for clinical *** is feasible for the aperture shape optimization involving the proposed method.

关键词： Aperture shape Column generation Conjugate gradient Gradient modulation Direct aperture optimization

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自制喉扩张管治疗外伤性喉气管狭窄

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中华创伤杂志 2005年第5期21卷 372-374页

作者：刘邦华孔维佳汪吉宝汪广平毕胜斌杨成章华中科技大学同济医学院附属协和医院耳鼻咽喉-头颈外科武汉430022

目的研究自制喉扩张管治疗外伤性喉气管狭窄的治疗效果,探讨放置喉扩张管的时限。方法62例外伤性喉气管狭窄患者,分为两组。第一组52例,为初次行喉扩张管治疗的患者。第二组10例,为行喉扩张管治疗失败后再次行喉扩张管治疗的患者。气管... 详细信息

目的研究自制喉扩张管治疗外伤性喉气管狭窄的治疗效果,探讨放置喉扩张管的时限。方法62例外伤性喉气管狭窄患者,分为两组。第一组52例,为初次行喉扩张管治疗的患者。第二组10例,为行喉扩张管治疗失败后再次行喉扩张管治疗的患者。气管插管全身麻醉下行颈前正中喉气管切开,尽量切除喉气管内瘢痕组织,置入喉扩张管。结果第一组患者术后9-12个月全部拔除喉扩张管,呼吸通畅,发音较好,劳动力恢复。第二组患者拔管后3-4个月出现再狭窄,再次行喉扩张管治疗后顺利拔管,带管期间无严重并发症,如呼吸道阻塞的发生。随访1-10年,来发现再次喉气管狭窄患者。结论自制喉扩张管制作简单、方便,治疗效果良好,无排斥反应。喉扩张管的留置时间至少应在9-12个月以上。

关键词：外伤性喉气管狭窄扩张管自制气管插管全身麻醉治疗效果严重并发症呼吸道阻塞气管切开瘢痕组织呼吸通畅排斥反应留置时间患者再次失败后气管内劳动力再狭窄拔管后治疗后未发现

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Channel measurements and models for high-speed train wireless communication systems in tunnel scenarios: a survey

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Science China(Information Sciences) 2017年第10期60卷 107-123页

作者： Yu LIU Ammar GHAZAL cheng-Xiang WANG Xiaohu GE yang yang Yapei zhang Shandong Provincial Key Laboratory of Wireless Communication Technologies Shandong University School of Engineering and Sustainable Development De Montfort University Institute of Sensors Signals and Systems School of Engineering & Physical Sciences Heriot-Watt University Department of Electronics and Information Engineering Huazhong University of Science and Technology Key Laboratory of Wireless Sensor Network & Communication Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences

The rapid developments of high-speed trains(HSTs) introduce new challenges to HST wireless communication systems. Realistic HST channel models play a critical role in designing and evaluating HST communication systems. Due to the length limitation, bounding of tunnel itself, and waveguide effect, channel characteristics in tunnel scenarios are very different from those in other HST scenarios. Therefore, accurate tunnel channel models considering both large-scale and small-scale fading characteristics are essential for HST communication systems. Moreover, certain characteristics of tunnel channels have not been investigated sufficiently. This article provides a comprehensive review of the measurement campaigns in tunnels and presents some tunnel channel models using various modeling methods. Finally, future directions in HST tunnel channel measurements and modeling are discussed.

关键词： 5G high-speed train(HST) tunnel scenario tunnel channel measurement tunnel channel model non-stationary statistical property

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In situ observation of the effect of Al N particles on bainitic transformation in a carbide-free medium carbon steel

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International Journal of Minerals,Metallurgy and Materials 2020年第5期27卷 620-629页

作者： Xiao-jie Zhao Zhi-nan yang Fu-cheng zhang State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao 066004China

The bainitic transformation of the steels with different mass fractions of N, ~0.002% and 0.021%, was observed in situ by using high-temperature metalloscope. Micrometer-and nanometer-sized aluminum nitride(AlN) particles were found in the steel with 0.021% *** boundaries, the interior of the grains, and Al N particles were used as initial nucleation sites of bainitic ferrite, and bainitic ferrite subunits served as new nucleation sites to induce secondary nucleation. The lengthening rate of bainitic ferrite varied at different nucleation sites, which was controlled by the repeated nucleation and growth of bainitic subunits. The Al N particles not only provided several nucleation sites, but also increased the autocatalytic effect on the transformation, further shortening the incubation period, promoting the bainitic transformation, and refining the bainitic microstructure.

关键词： bainitic steel In situ observation phase transformation aluminum nitride

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Friction and wear behavior and mechanism of low carbon microalloyed steel containing Nb

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China Foundry 2023年第3期20卷 263-270页

作者： Mei-yi Yuan Jia-cheng zhang Yi-tao yang School of Materials Science and Engineering Shanghai UniversityShanghai 200444China

Dry sliding friction and wear test of Nb containing low carbon microalloyed steel was carried out at room temperature,and the effect of Nb on the wear behavior of the steel,as welll as the mechanism was *** electron microscopy(SEM) and energy dispersive spectrometry(EDS) were employed to analyze the morphology and composition of the worn surface,and the structure evolution of the plastic deformation *** carbide content and type in the steel were analyzed by the electrolytic extraction device and X-ray diffraction(XRD).The experimental results demonstrate that the addition of 0.2% Nb can refine the grain and generate Nb C to improve the wear resistance of the *** enhancing the load and speed of wear experiment,the wear mechanism of the test steel with 0.2% Nb changes from slight oxidation wear to severe adhesion wear and oxidation *** with the load,the increase in the rotation speed exerts a greater influence on the wear of the test steel.

关键词： Nb content low carbon microalloyed steel friction and wear carbide

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Plasma level of neuron specific enolase in patients with acute cerebral infarction:A case-control study

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Neural Regeneration Research 2009年第1期4卷 62-66页

作者： Guoping Tian yang zhang Weiping cheng Department of Neurology Shenyang First People's Hospital (i. e. Shenyang Brain Hospital) Shengyang 110041 Liaoning Province China Department of Neurology First Hospital Affiliated to Heilongjiang University of Traditional Chinese Medicine Harbin 150040 Heilongjiang Province China

BACKGROUND： The plasma level of neuron specific enolase （NSE） can be used to diagnose and evaluate neuronal injury and predict early prognosis. OBJECTIVE： To observe the dynamic changes in plasma levels of NSE in patients with acute cerebral infarction, and to investigate its correlations with disease severity and prognosis. DESIGN, TIME AND SETTING： This non-randomized, concurrent case-control experiment was performed at the Department of Neurology, First Hospital Affiliated to Heilongjiang University of Traditional Chinese Medicine between May and July 2007. PARTICIPANTS： Eighteen patients with acute cerebral infarction, who received treatment at the Department of Neurology, First Hospital Affiliated to Heilongjiang University of Traditional Chinese Medicine between May and July 2007, were recruited into the patient group. An additional 10 healthy individuals, who received health examinations simultaneously, were included as controls. METHODS： Following admission （within 3 days） and at days 6, 12, and 30 subsequent to acute cerebral infarction attack, 3 mL venous blood was taken from each patient before the morning meal to determine the plasma level of NSE by enzyme-labeled immunosorbent assay. One-time blood extraction was performed in each healthy subject during the health examination for the same purpose as in patients. At 6 and 30 days following acute cerebral infarction attack, CT examination was performed for calculation of cerebral infarction volume according to the Tada formula. Following admission and at 30 days of disease invasion, all patients were scored by the National Institutes of Health Stroke Scale （NIHSS, 13 items）. MAIN OUTCOME MEASURES： Comparison of NSE plasma level between acute cerebral infarction patients and healthy individuals; correlations of NSE plasma level in acute cerebral infarction patients with cerebral infarction volume, NIHSS score, and prognosis. RESULTS： Following admission and at days 6 and 12 of disease invasion, t

关键词： neuron specific enolase acute cerebral infarction prognosis functional neurological deficit

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CT动态增强扫描对周围型肺癌的诊断评价

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实用放射学杂志 2003年第12期19卷 1081-1083页

作者：徐秋贞储成凤杨明张俭郏爱明东南大学附属中大医院放射科东南大学附属中大医院放射科江苏南京210009

目的　探讨动态增强CT对肺癌的诊断价值。方法　选择直径≤ 4cm的孤立性肺结节 42例行动态CT增强研究 ,其中经病理及临床证实的周围型肺癌 3 0例 ,测量其增强前后各时间段扫描的CT值变化 ,绘制时间 -密度曲线 ,分析肺癌的增强特征。结... 详细信息

目的　探讨动态增强CT对肺癌的诊断价值。方法　选择直径≤ 4cm的孤立性肺结节 42例行动态CT增强研究 ,其中经病理及临床证实的周围型肺癌 3 0例 ,测量其增强前后各时间段扫描的CT值变化 ,绘制时间 -密度曲线 ,分析肺癌的增强特征。结果　孤立性肺结节静注碘剂 10 0ml后 ,所有肺癌均显著强化 ,分 3个类型 :均匀小结节状强化 19例 ,不均匀中心团块状强化 5例和周边不规则强化 6例。结论　动态CT增强扫描对周围型肺癌的诊断及鉴别诊断极具价值

关键词：肺肺癌体层摄影,X线计算机动态增强

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Interference-Limited Device-to-Device Multi-User Cooperation Scheme for Optimization of Edge Networking

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Journal of Computer Science & Technology 2016年第6期31卷 1096-1109页

作者： Hong-cheng Huang Jie zhang Zu-Fan zhang Zhong-yang Xiong College of Computer Science Chongqing University Chongqing 400044 China School of Communication and Information Engineering Chongqing University of Posts and Telecommunications Chongqing 400065 China

Device-to-device （D2D） communication is an emerging technology for improving cellular networks, which plays an important role in realizing Internet of Things （IoT）. The spectrum efficiency, energy efficiency and throughput of network can be enhanced by the cooperation among multiple D2D users in a self-organized method. In order to limit the interference of D2D users and load off the energy consumption of D2D users without decreasing communication quality, an interference- limited multi-user cooperation scheme is proposed for multiple D2D users to solve the energy problem and the interference problem in this paper. Multiple D2D users use non-orthogonal spectrums to form clusters by self-organized method. Multiple D2D users are divided into different cooperative units. There is no interference among different cooperative units so as to limit the interference of each D2D user in cooperative units. When the link capacity cannot meet the requirements of the user rate, it will produce an interrupt event. In order to evaluate the communication quality, the outrage probability of D2D link is derived by considering link delay threshold, data rate and interference. Besides the energy availability and signal-to-noise ratio （SNR） of each D2D user, the distance between D2D users is considered when selecting the relaying D2D users so as to enhance the signal-to-interference-plus-noise ratio （SINR） of D2D receiving users. Combining the derived outrage probability, the relationships among the average link delay threshold, the efficiency of energy and the efficiency of capacity are studied. The simulation results show that the interference-limited multiple D2D users cooperation scheme can not only help to offioad energy consumption and limit the interference of D2D users, but also enhance the efficiency of energy and the efficiency of capacity.

关键词： device-to-device (D2D) user cooperation relay selection efficiency of energy efficiency of capacity Internetof Things (IoT)

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系统性生物力学评价大鼠股骨缺损修复进程的实验研究

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中华创伤骨科杂志 2018年第3期20卷 247-253页

作者：曹天庆程朋真杨柳张帅帅李东林宋岳刘斌吴昊裴国献空军军医大学西京医院骨科西安710032 解放军第四六三医院骨科沈阳110042

目的系统性评估SD大鼠股骨孔性缺损在修复过程中力学性能的恢复。方法选取18只健康雌性SD大鼠，随机分为实验A组、实验B组和对照组（每组6只）。实验组构建双侧股骨干钻孔缺损模型，每侧2孔缺损；对照组行假手术处理。实验A组于术后4周... 详细信息

目的系统性评估SD大鼠股骨孔性缺损在修复过程中力学性能的恢复。方法选取18只健康雌性SD大鼠，随机分为实验A组、实验B组和对照组（每组6只）。实验组构建双侧股骨干钻孔缺损模型，每侧2孔缺损；对照组行假手术处理。实验A组于术后4周取材，实验B组于术后8周取材，对照组于术后4、8周取材。对3组骨标本进行线弹性、黏弹性及疲劳测试评价，显微CT扫描测量其新生骨体积分数和骨密度，天狼星红染色观察新生骨中Ⅰ型胶原再生情况。结果实验A组股骨标本的弹性模量、最大载荷、抗压强度和条件屈服极限显著低于实验B组，实验B组又显著低于对照组，差异均有统计学意义（P〈0．05）。在7200s时，实验A组股骨标本的松弛量【（14．56±0．69）MPa】和蠕变量（11．37％±0．70％）显著高于实验B组[（11．06±0．63）MPa、8．98％±0．40％】，实验B组又显著高于对照组【（6．99±0．56）MPa、5．10％±0．23％】，差异均有统计学意义（P〈0．05）。在20—200N、20—300N和20—400N的载荷振幅区间，实验A组的循环次数（6044．3±879．7、4093．3±628．5、1919．3±847．5）显著低于实验B组（10192．3±1109．1、6750．7±818．0、3376．7±671．3），实验B组又显著低于对照组（28068．3±2702．6、11788．3±1141．6、5296．3±735．0），差异均有统计学意义（P〈0．05）。显微CT扫描显示：实验A组股骨标本的骨体积分数和骨密度显著低于实验B组，实验B组又显著低于对照组，差异均有统计学意义（P〈0．05）。天狼星红染色结果显示实验B组股骨缺损区域的Ⅰ型胶原纤维基本完全再生。结论采用系统的力学评价方法可真实反映出大鼠股骨孔性缺损在修复过程中力学性能恢复的特点，丰富了对骨损伤修复评价的基础研究。

关键词：股骨骨缺损生物力学大鼠

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Spontaneously bundled nanotubes exhibit greatly enhanced emission via inter-nanotube energy transfer

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Science China Chemistry 2016年第10期59卷 1348-1351页

作者： cheng Peng Juan yang Yifan zhang Yibin zhang Yanke Che Beijing National Laboratory for Molecular Sciences Key Laboratory of PhotochemistryInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Institute of Applied Chemistry Henan Polytechnic UniversityJiaozuo 454003China

Spontaneously bundled nanotubes assembled from chiral perylene diimide molecules exhibit greatly enhanced emission via inter-nanotube excitation energy transfer. The formation of densely packed superstructures is an effective approach for high fluorescence quantum yield in assembled nanomaterials without compromising optoelectronic properties.

关键词： nanotube fluorescence quantum yield inter-tube energy transfer

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