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基于风格迁移的柔性输尿管内窥镜图像深度估计

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天津大学学报（自然科学与工程技术版） 2025年第1期58卷 47-55页

作者：辛运帏尹晶晶赵煜代煜崔亮殷小涛南开大学网络空间安全学院天津300071 天津市网络与数据安全技术重点实验室天津300071 南开大学机器人与信息自动化研究所天津300350 民航总医院泌尿外科北京100123 解放军总医院第四医学中心泌尿外科北京100048

输尿管内窥镜手术是目前针对肾结石的主流治疗方案,其外形细长、镜体柔软,能够灵活穿越人体自然腔道的内径狭窄的尿道和输尿管,检查视野范围更广,使医生能够更好地观察到病变区域.但一般的输尿管内窥镜仅配备单目摄像头进行配合手术操作... 详细信息

输尿管内窥镜手术是目前针对肾结石的主流治疗方案,其外形细长、镜体柔软,能够灵活穿越人体自然腔道的内径狭窄的尿道和输尿管,检查视野范围更广,使医生能够更好地观察到病变区域.但一般的输尿管内窥镜仅配备单目摄像头进行配合手术操作,无法借助额外设备获取数据导致了其图像信息的匮乏;同时,相比于胃肠、鼻镜等手术场景,本研究的肾内场景在不具备公开数据集的同时,图像质量参差不齐,表面纹理细节不足,孔洞区域褶皱少,受模糊反光等干扰大,都易使深度估计受到影响针对以上问题,提出了一种基于改进风格迁移模型的深度估计方法.该方法首先根据术前CT图像重建肾脏内部腔道模型并提取中心路径,将虚拟内窥镜的摄像头设置在插值后的路径点上,构建了虚拟内窥镜漫游图像与深度估计图像一一对应的数据集,并基于此数据集训练了一个深度估计模型;随后,使用添加高效通道注意力(ECA)模块的改进风格迁移模型,将真实内窥镜图像域迁移至虚拟内窥镜图像域;最后,再将经由风格迁移产生的虚拟内窥镜图像送入上述训练得来的深度估计模型中,最终实现真实内窥镜图像的深度估计.所提方法的可行性及有效性在输尿管钬激光碎石术的图像中得到验证.

关键词：深度估计风格迁移注意力机制深度学习

Characterization and catalytic performance of CeO_2-Co/SiO_2 catalyst for Fischer-Tropsch synthesis using nitrogen-diluted synthesis gas over a laboratory scale fixed-bed reactor

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Journal of Natural Gas Chemistry 2008年第1期17卷 17-23页

作者： Xiaoping dai Changchun yu The Key Laboratory of Catalysis China National Petroleum Corporation China University of Petroleum Beijing 102249 China

The surface species of CO hydrogenation on CeO2-Co/SiO2 catalyst were investigated using the techniques of temperature programmed reaction and transient response method. The results indicated that the formation of H2O and CO2 was the competitive reaction for the surface oxygen species, CH4 was produced via the hydrogenation of carbon species step by step, and C2 products were formed by the polymerization of surface-active carbon species （-CH2-）. Hydrogen assisted the dissociation of CO. The hydrogenation of surface carbon species was the rate-limiting step in the hydrogenation of CO over CeO2-Co/SiO2 catalyst. The investigation of total pressure, gas hourly space velocity （GHSV）, and product distribution using nitrogen-rich synthesis gas as feedstock over a laboratory scale fixed-bed reactor indicated that total pressure and GHSV had a significant effect on the catalytic performance of CeO2-Co/SiO2 catalyst. The removal of heat and control of the reaction temperature were extremely critical steps, which required lower GHSV and appropriate CO conversion to avoid the deactivation of the catalyst. The feedstock of nitrogen-rich synthesis gas was favorable to increase the conversion of CO, but there was a shift of product distribution toward the light hydrocarbon. The nitrogen-rich synthesis gas was feasible for F-T synthesis for the utilization of remote natural gas.

关键词： CeO2-Co/SiO2 catalyst Fischer-Tropsch synthesis surface species reaction condition nitrogen-rich synthesis gas product distribution

H_2-induced CO adsorption and dissociation over Co/Al_2O_3 catalyst

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Journal of Natural Gas Chemistry 2008年第4期17卷 365-368页

作者： Xiaoping dai Changchun yu The Key Laboratory of Catalysis China National Petroleum Corporation China University of Petroleum Beijing 102249 China

The activation of adsorbed CO is an important step in CO hydrogenation. The results from TPSR of pre-adsorbed CO with H2 and syngas suggested that the presence of H2 increased the amount of CO adsorption and accelerated CO dissociation. The H2 was adsorbed first, and activated to form H＊ over metal sites, then reacted with carbonaceous species. The oxygen species for CO2 formation in the presence of hydrogen was mostly OH^＊, which reacted with adsorbed CO subsequently via CO^＊＋OH^＊ → CO2^＊＋H^＊; however, the direct CO dissociation was not excluded in CO hydrogenation. The dissociation of C-O bond in the presence of H2 proceeded by a concerted mechanism, which assisted the Boudourd reaction of adsorbed CO on the surface via CO^＊＋2H^＊ → CH^＊＋OH^＊. The formation of the surface species （CH） from adsorbed CO proceeded as indicated with the participation of surface hydrogen, was favored in the initial step of the Fischer-Tropsch synthesis.

关键词： H2 induced CO adsorption dissociation methanation Co/Al2O3 catalyst

Effects of pretreatment and reduction on the Co/Al_2O_3 catalyst for CO hydrogenation

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Journal of Natural Gas Chemistry 2008年第3期17卷 288-292页

作者： Xiaoping dai Changchun yu The Key Laboratory of Catalysis China National Petroleum Corporation China University of Petroleum Beijing 102249 China

The purpose of this study was to investigate the effect of preadsorbed CO at different temperatures, calcination temperatures, the combined influence of reduction temperature and time, and pretreatment using hydrogen or syngas as reduction agents on the F-T synthesis （FTS） activity and selectivity of Co/Al2O3 catalyst. The reactivity of the carbon species at higher preadsorption temperature with H2 in TPSR decreased, whereas the carbon-containing species showed higher reactivity over Co/Al2O3 catalyst with low calcination temperature. This agreed well with the order of catalytic activity for F-T synthesis on this catalyst. The catalytic activity of the catalyst varied with reduction temperature and time remarkably. CODEX optimization gave an optimum reduction temperature of 756 K and reduction time of 6.2 h and estimated C5＋ yield perfectly. The pretreatment of Co/Al2O3 catalyst with different reduction agents （hydrogen or syngas） showed important influences on the catalytic performance. A high CO conversion and C5＋ yield were obtained on the catalyst reduced by hydrogen, whereas methane selectivity on the catalyst reduced by syngas was much higher than that on the catalyst reduced by hydrogen.

关键词： CO hydrogenation Co/Al2O3 catalyst CO adsorption H2-TPSR surface carbon species reduction condition pretreatment

Synthesis of High Molecular Weight Polyethylene and E-MA Copolymers Using Iminopyridine Ni(Ⅱ) and Pd(Ⅱ) Complexes Containing a Flexible Backbone and Rigid Axial Substituents

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Chinese Journal of Polymer Science 2023年第2期41卷 233-239页

作者： yu-Dan Liao Qi Cai Sheng-yu dai School of Chemical and Environmental Engineering Anhui Polytechnic UniversityWuhu241000China Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationAnhui UniversityHefei230601China

Suppressing the chain transfer reactions during polymerization in late-transition metal-catalyzed olefin polymerization systems is the key to obtaining high molecular weight polyolefin materials. In this work, two efficient strategies(“sandwich” and rotation-restricted strategies)to retard chain transfer reactions in ethylene(co)polymerization were employed for the iminopyridyl system. Herein, a family of iminopyridyl Ni(Ⅱ)and Pd(Ⅱ) complexes with a flexible backbone and rigid axial bulky aryl substituents were designed, synthesized and characterized. In ethylene polymerization, the iminopyridyl Ni(Ⅱ) and Pd(Ⅱ) catalysts using the two strategies exhibited reasonable activities and generated highly branched polyethylenes with high molecular weights, where catalysts with dibenzosuberyl substituents exhibited significantly higher activities and produced higher molecular weight polyethylene than catalysts with 8-arylnaphthalenyl substituent. A similar trend of activities and molecular weights was also found in the copolymerization of ethylene with MA using the Pd(Ⅱ) catalysts. Moreover, highly branched E-MA copolymers with moderate to high molecular weights and high incorporation ratios(up to 17.4 mol%) were generated with the two Pd(Ⅱ) catalysts. Most interestingly, as compared with the dibenzhydryl Ni(Ⅱ) and Pd(Ⅱ) catalysts, the catalysts using the two strategies exhibited a superior ability to retard the chain transfer reactions and generated polymers and copolymers with 1-2 orders of magnitude higher molecular weights during ethylene(co)polymerization.

关键词： Ni(Ⅱ)and Pd(Ⅱ) Suppressing chain transfer High molecular weight Ethylene(co)polymerization

A NOTE ON THE NONLINEAR CONJUGATE GRADIENT METHOD

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Journal of Computational Mathematics 2002年第6期20卷 575-582页

作者： dai, yu-hong yuan, Ya-xiang Chinese Acad Sci Acad Math & Syst Sci Inst Computat Math & Sci Engn Comput State Key Lab Sci & Engn Comput Beijing 100080 Peoples R China

Discusses several aspects of the linear conjugate gradient method for unconstrained optimization problems. General condition concerning the scalar; Convergence of the famous Fletcher-Reeves and Polak-Ribiere-Polyak co... 详细信息

关键词： unconstrained optimization conjugate gradient line search global convergence

Assembly of a Heteronuclear POM {[K_(5)Na_(6)Cu^(Ⅱ)_(5)(CH_(3)COO)_(20)(CH_(3)CN)]Cl}_(n) via Two Kinds of Clusters as the Basic Bridge Unit

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Chinese Journal of Structural Chemistry 2018年第10期37卷 1612-1618页

作者： dai yu-Mei XU Jie Minnan Science and Technology Institute Fujian Normal UniversityQuanzhou 362332China

A novel 3D hetero-nuclear framework,namely{[K_(5)Na_(6)Cu^(Ⅱ)_(5)(CH_(3)COO)_(20)(CH_(3)CN)]Cl}_(n)(1),was obtained by hydrothermal *** metal centers(including sodium/potassium or/and copper)were coordinated to acetate anions in such two heteronuclear clusters,***,nine kinds of binding modes for acetate anions were illustrated in polymer 1,with the first reported pentadentate coordination mode for acetate ligand.

关键词： hydrothermal synthesis acetate Hgand heteronuclear clusters of sodium/potassium and copper

Comparison of LaFeO_3,La_(0.8)Sr_(0.2)FeO_3,and La_(0.8)Sr_(0.2)Fe_(0.9)CO_(0.1)O_3 perovskite oxides as oxygen carrier for partial oxidation of methane

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Journal of Natural Gas Chemistry 2008年第4期17卷 415-418页

作者： Xiaoping dai Changchun yu Qiong Wu The Key Laboratory of Catalysis China National Petroleum Corporation China University of Petroleum Beijing 102249 China

Comparison of LaFeO3, La0.8Sr0.2FeO3, and La0.8Sr0.2Fe0.9CO0.1O3 perovskite oxides as oxygen carrier for partial oxidation of methane in the absence of gaseous oxygen was investigated by continuous flow reaction and sequential redox reaction, Methane was oxidized to syngas with high selectivity by oxygen species of perovskite oxides in the absence of gaseous oxygen. The sequential redox reaction revealed that the structural stability and continuous oxygen supply in redox reaction decreased over La0.8Sr0.2Fe0.9Co0. 1O3 oxide, while LaFeO3 and La0.8Sr0.2FeO3 exhibited excellent structural stability and continuous oxygen supply.

关键词： perovskite oxides oxygen carrier methane synthesis gas continuous flow reaction sequential redox reaction

Method of SLAS’s ground track manipulation based on tangential impulse thrust

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Journal of Systems Engineering and Electronics 2023年第5期34卷 1285-1293页

作者： LE Xinlong CAO Xibin dai yu WU Fan School of Astronautics Harbin Institute of TechnologyHarbin 150001China

Satellites with altitudes below 400 km are called super low altitude satellites(SLAS),often used to achieve responsive imaging ***,it is important for the manipulation of its ground *** at the problem of ground track manipulation of SLAS,a control method based on tangential impulse thrust is ***,the equation of the longitude difference between SLAS and the target point on the target latitude is derived based on Gauss’s variational *** this basis,the influence of the tangential impulse thrust on the ground track’s longitude is ***,the method for ground track manipulation of SLAS under the tangential impulse thrust is *** simulation results verify the effective-ness of the method,after manipulation,the satellite can visit the target point and revisit it for multiple days.

关键词： super low altitude satellite(SLAS) ground track drift modeling ground track manipulation tangential impulse thrust