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Aperture shape optimization in intensity-modulated radiation therapy planning

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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

IMAGE SEGMENTATION BY PIECEWISE CONSTANT MUMFORD-SHAH MODEL WITHOUT ESTIMATING THE CONSTANTS

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Journal of Computational Mathematics 2006年第3期24卷 435-443页

作者： Xue-cheng Tai chang-hui Yao CIPR Department of Mathematics University of Bergen Norway Department of Mathematics University of Bergen Norway

In this work, we try to use the so-called Piecewise Constant Level Set Method （PCLSM） for the Mumford-Shah segmentation model. For image segmentation, the Mumford-Shah model needs to find the regions and the constant values inside the regions for the segmen- tation. In order to use PCLSM for this purpose, we need to solve a minimization problem using the level set function and the constant values as minimization variables. In this work, we test on a model such that we only need to minimize with respect to the level set function, i.e., we do not need to minimize with respect to the constant values. Gradient descent method and Newton method are used to solve the Euler-Lagrange equation for the minimization problem. Numerical experiments are given to show the efficiency and advantages of the new model and algorithms.

关键词： PCLSM Image Segmentation Mumford-Shah model.

Design, Synthesis and in vitro Evaluation of Thiazole Derivatives of Ibuprofen as Cyclooxygenase-2 Inhibitors

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Chinese Chemical Letters 2006年第3期17卷 325-328页

作者： chang Bin GUO Zhe Feng CAI Zong Ru GUO Zhi Qiang FENG Feng Ming CHU gui-Fang cheng Feng Ming CHU Gui Fang CHENG Institute of Materia Medica Chinese Academy of Medical Science and Peking Union Medical College Beijing 100050

A series of thiazole derivatives of ibuprofen, as cyclooxygenase-2 Inhibitors, were designed, synthesized and in vitro evaluated.

关键词： Cyclooxygenase-2 (COX-2) inhibitor ibuprofen thiazole derivative.

Entrainment range affected by the heterogeneity in the amplitude relaxation rate of suprachiasmatic nucleus neurons

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Chinese Physics B 2019年第1期28卷 663-668页

作者： chang-gui Gu Ping Wang Hui-Jie Yang Business School University of Shanghai for Science and Technology

Adaption of circadian rhythms in behavioral and physiological activities to the external light–dark cycle is achieved through the main clock, i.e., the suprachiasmatic nucleus(SCN) of the brain in mammals. It has been found that the SCN neurons differ in the amplitude relaxation rate, which represents the rigidity of the neurons to the external amplitude disturbance. Thus far, the appearance of that difference has not been explained. In the present study, an alternative explanation based on the Poincare′ model is given which takes into account the effect of the difference in the entrainment range of the SCN. Both our simulation results and theoretical analyses show that the largest entrainment range is obtained with suitable difference in the case that only a part of SCN neurons are sensitive to the light information. Our findings may give an alternative explanation for the appearance of that difference(heterogeneity) and shed light on the effects of the heterogeneity in the neuronal properties on the collective behaviors of the SCN neurons.

关键词： amplitude relaxation rate entrainment range heterogeneity

Early expression of surfactant proteins D in Fusarium solani infected rat cornea

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International Journal of Ophthalmology(English edition) 2012年第3期5卷 297-300页

作者： cheng-Ye Che, gui-Qiu Zhao Department of Ophthalmology the Affiliated Hospital of Qingdao University Qingdao 266003 Shandong Province China Binzhou Hubin Eye Hospital Binzhou 256600 Shandong Province China

AIM: To investigate the early expression of surfactant proteins D(SP-D) in Fusarium solani infected rat cornea. METHODS: Wistar rats were divided into group A, B and C randomly. The right eyes were chosen as the experiment one. Group A was control group. Group B was not inoculated with Fusarium solani. Group C was taken as fusarium solani keratitis model. Five rats in group B and C were executed randomly at 6, 12, 24, 48 and 96 hours respectively after the experimental model being established. The expression of SP-D was assessed through immunohistochemistry and reverse transcription polyrnerase chain reaction(RT-PCR). RESULTS: RT-PCR detected that the SP-D mRNA expression was low in the corneal of normal rats and group B. The expression of fungal infected cornea increased gradually and reached the peak at 24 hours in group C. The synchronous expression of group B and C were in significant difference (P<0.01). Immunohistochemisty discovered the protein of SP-D expression was increased gradually from 12 hours and reached the peak at 48 hours in group C. The synchronous expression of group B and C were also in significant difference (P<0.01). CONCLUSION: There exists SP-D in rat corneal tissue and the expression is significantly increased at the early period of fusarium solani infected cornea. SP-D may play a role in the early innate immunity response of the corneal resistance to Fusarium solani infection.

关键词： keratitis Fusarium solani surfactant protein D innate immune

Surface modification of Ti-45Al-8.5 Nb alloys by microarc oxidation to improve high-temperature oxidation resistance

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Progress in Natural Science:Materials International 2018年第3期28卷 386-390页

作者： Fang cheng Shasha Li Wanyuan gui Junpin Lin State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing

Microarc oxidation（MAO）electrolysis plasma deposition was used to prepare Al2O3coatings on Ti-45Al-8.5 Nb alloys to improve high temperature oxidation *** surface and cross-section morphologies before and after high-temperature oxidation,the chemical composition,and the phase identification of the coatings were investigated by scanning electron microscopy（SEM）,electron probe microanalyses（EPMA）,and X-ray diffraction（XRD）.The results show that Al2O3coatings with a thickness of approximately 8μm can be obtained on the Ti-45Al-8.5 Nb alloys by MAO for 600 *** samples with the Al2O3coatings exhibited better high-temperature oxidation resistance.A minimal weight gain of only 0.396 g/m2after 100 h oxidation at 900°C was observed for the coatings formed with a deposition voltage of 400 V and using a duty cycle of 3%.The deposition mechanism of the Al2O3coatings and the effect of the MAO parameters are also described.

关键词： Cathode electrolytic plasma Microarc oxidation High temperature oxidation resistance High Nb-Ti Al alloys Coating

铀对α-Al_(2)O_(3)中氢与本征点缺陷相互作用的影响

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原子与分子物理学报 2025年第5期42卷 123-129页

作者：杨飞龙向鑫胡立张桂凯陈长安中国工程物理研究院材料研究所江油621908

在长期高温服役过程中,铀床的氚渗透泄露问题是聚变堆涉氚系统中需要关注的焦点之一,而一种行之有效的解决思路是在内壁制备阻氚涂层.然而,服役过程中通过热扩散渗入涂层内部的铀可能在阻氚涂层氢行为中起作用,进而影响其服役可靠性.基... 详细信息

在长期高温服役过程中,铀床的氚渗透泄露问题是聚变堆涉氚系统中需要关注的焦点之一,而一种行之有效的解决思路是在内壁制备阻氚涂层.然而,服役过程中通过热扩散渗入涂层内部的铀可能在阻氚涂层氢行为中起作用,进而影响其服役可靠性.基于此,采用第一性原理计算方法,研究了铀对α-Al_(2)O_(3)中氢与本征点缺陷相互作用的影响.结果发现,铀对α-Al_(2)O_(3)中空位型本征点缺陷及氢相关缺陷的存在形式、电荷态及相对稳定性有重要影响.从形成能观点来看,铀对α-Al_(2)O_(3)中空位型本征点缺陷及氢相关缺陷的形成有利,且α-Al_(2)O_(3)中空位型点缺陷对氢的捕陷能力因铀的引入显著增加.研究结果对α-Al_(2)O_(3)基内壁阻氚涂层在氚工艺系统铀床中应用的可靠性评估具有重要的指导意义.

关键词：铀本征点缺陷氢相关缺陷相互作用 α-Al_(2)O_(3)

A Sufficient Condition for Planar Graphs with Maximum Degree 8 to Be 9-totally Colorable

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Acta Mathematica Sinica,English Series 2014年第6期30卷 993-1006页

作者： Jian Sheng CAI chang Chun TENG gui Ying YAN School of Mathematics and Information Sciences Weifang University Academy of Mathematics and Systems Science Chinese Academy of Sciences

A total k-coloring of a graph G is a coloring of V（G） ∪ E（G） using k colors such that no two adjacent or incident elements receive the same color. The total chromatic number χ＇＇（G） is the smallest integer k such that G has a total k-coloring. It is known that if a planar graph G has maximum degree △≥ 9, then ）χ″（G） =△＋ 1. In this paper, we prove that if O is a planar graph with maximum degree 8 and without a fan of four adjacent 3-cycles, then χ″（G） =- 9.

关键词： Total coloring planar graph a fan of four adjacent 3-cycles

Postsynthetic Modification of Metal-Organic Frameworks through Click Chemistry

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Chinese Journal of Chemistry 2016年第2期34卷 186-190页

作者： Bo gui Xiangshi Meng Hai Xu cheng Wang Key Laboratory of Biomedical Polymers (Ministry of Education) College of Chemistry and Molecular Sciences Wuhan University Wuhan Hubei 430072 China College of Chemistry and Chemical Engineering Central South University Changsha Hunan 410083 China

The postsynthetic modification （PSM） of metal-organic frameworks （MOFs） has emerged as a powerful tool to chemically tailor the interior of MOFs. In this review, we summarize the research progress of PSM of MOFs t... 详细信息

关键词： postsynthetic modification metal-organic frameworks click chemistry azide-alkyne click reaction thiol-ene reaction