检索结果-南通市图书馆

Identification of a Reliable DFT Calculation Method to Predict the Ground-and Excited-State Properties of Nickel(Ⅱ) Complexes with Porphyrin in Crude Oil

在线全文

学校读者我要写书评

暂无评论

China Petroleum Processing & Petrochemical Technology 2023年第4期25卷 106-116页

作者： Pu Ning Ren Qiang Hu Dawei Fang Wei Yang Qinghe Wang Zhen Hu Anpeng Xu Lei ge Xin SINOPEC Research Institute of Petroleum Processing Co. Ltd.Beijing 100083China Institute of Nuclear Agricultural Sciences Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang ProvinceZhejiang UniversityHangzhou 310058China SINOPEC geophysical Research Institute Nanjing 211103China

Metalloporphyrins have devastating effects on the deep processing and efficient utilization of petroleum resources. Various porphyrins are derived from porphin by substitution at the β, meso, or both positions. Herein, we focus on the interaction between nickel(Ⅱ) and the porphyrin skeleton. Five different density functionals were selected for determining a reliable approach to simulate porphyrin-nickel(Ⅱ) complexes. At D4h symmetry, the 10b1g, 15a1g, 4e1g and 9b2g were dominated by the 3d character of nickel. Compared with pure density functional, the hybrid functional gave larger highest occupied molecular orbital(HOMO) and lowest unoccupied molecular orbital(LUMO) gap, and the higher HOMO-LUMO gap also corresponded to a higher excitation energy. The characteristic Soret and Q bands modeled by timedependent density functional theory(TDDFT) calculations matched well with experimental results, and the absorption was discussed in detail with natural transition orbitals(NTO) analysis. Furthermore, the binding character of nickel(Ⅱ) with various substituted porphyrins were calculated at perdew-burke-ernzerhof(PBE) level, showed that the geometry and complexation behavior of porphyrin-nickel(Ⅱ) complexes could be significantly tuned by different substituents. The symmetry of the complex was reduced and the skeleton ring get distortion when introducing different substituents. Compared with ETIO porphyrin, the introduction of phenyl on the β position can expand the conjugated system and promote the covalent character of Ni-N bond.

关键词： porphyrin-nickel(Ⅱ) DFT/TDDFT binding character spectroscopic properties substituent effect

Effect of welding speed on microstructure and mechanical properties of Al−Mg−Mn−Zr−Ti alloy sheet during friction stir welding

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2021年第12期31卷 3626-3642页

作者： Tian DING Hong-ge YAN Ji-hua CHEN Wei-jun XIA Bin SU School of Materials Science and Engineering Hunan UniversityChangsha 410082China Hunan Provincial Key Laboratory of Spray Deposition Technology&Application Hunan UniversityChangsha 410082China

Effects of welding speed on the microstructure evolution in the stir zone(SZ)and mechanical properties of the friction stir welding(FSW)joints were studied by OM,XRD,SEM,TEM,EBSD and tensile *** with the base metal(BM),an obviously fine dynamic recrystallization(DRX)microstructure occurs in the SZ and the DRX grain size decreases from 5.6 to 4.4μm with the increasing of welding *** DRX microstructure is mainly achieved by continuous dynamic recrystallization(CDRX)mechanism,strain induced boundary migration(SIBM)mechanism and particle stimulated nucleation(PSN)***,the geometric coalescence and the burke−Turnbull mechanism are the main DRX grain growth *** all the welding speeds,the joint welded at rotation speed of 1500 r/min and welding speed of 75 mm/min has the greatest tensile properties,*** tensile strength(UTS)of(509±2)MPa,yield strength(YS)of(282±4)MPa,elongation(El)of(23±1)%,and the joint efficiency of 73%.

关键词： friction stir welding mechanical properties dynamic recrystallization nucleation mechanism grain growth mechanism

在线全文

学校读者我要写书评

暂无评论

托马斯·柏克小说里的华人移民社会

贵州师范大学学报（社会科学版） 2006年第2期 109-112页

作者：葛桂录福建师范大学文学院福建福州350007

英国作家托马斯.柏克素以描写伦敦莱姆豪斯的“中国城”著称。他对中国题材的兴趣来自童年时代与中国人结下的友谊,来自切实的生活经历。既直面生活的阴暗与丑陋,又试图唤起人们的怜悯与同情。本着这种创作意图,他笔下的中国人形象不出... 详细信息

英国作家托马斯.柏克素以描写伦敦莱姆豪斯的“中国城”著称。他对中国题材的兴趣来自童年时代与中国人结下的友谊,来自切实的生活经历。既直面生活的阴暗与丑陋,又试图唤起人们的怜悯与同情。本着这种创作意图,他笔下的中国人形象不出两类模式,即心地善良、淳朴温厚一类;狡狯不端的市井细民一类。因而跳出西方“中国城”小说通常的套路,并未贴上“中国人都是恶棍”的种族歧视的标签。

关键词：托马斯·柏克中国城小说华人移民中国形象

Deep brain stimulation in the treatment of secondary dystonia

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2006年第24期119卷 2069-2074页

作者： ZHANG Jian-guo,ZHANG Kai,WANG Zhong-cheng,ge Ming and MA Yu Department of Neurosurgery,Beijing Tiantan Hospital,Capital University of Medical Sciences Functional Neurosurgical Department,Beijing Neurosurgical Institute,Beijing 100050,China Department of Neurosurgery Beijing Tiantan Hospital Capital University of Medical Sciences

Background Dystonia is one of the most challenging movement disorders to treat. Medications and surgeries are the two methods to control dystonic symptoms. For patients with dystonia in whom symptoms are inadequately controlled with pharmacologic measures, the use of deep brain stimulation （DBS） can improve symptoms and enhance functional capacity. The best candidate for DBS is believed to be primary generalized dystonia, especially the DYT-1 type. Here, we report 9 cases of secondary dystonia to explore the feasibility, indications and complications of DBS in the treatment of secondary dystonia. Methods From July 2003 to June 2006, nine patients with secondary dystonia underwent surgery at Beijing Tiantan Hospital. Among them, 2 were diagnosed as having tardive dystonia, 1 had posttraumatic dystonia, 3 had a history of perinatal anoxia, 1 had neonatal pathologic jaundice, and 2 had no exact contributory history; MRI showed bilateral lentiform nuclei degeneration in one patient. Six patients underwent bilateral subthalamic nucleus （STN）-DBS, two underwent unilateral STN-DBS, the other underwent left STN and fight globus pallidus internus（GPi）-DBS. Results With intraoperative microelectrode recording, the targeted nucleus was accurately localized. Tentative stimulation could decrease muscle tension to the same extent, but twisting was not obviously improved. Follow-up for 3 months to 3 years showed satisfactory results in 3 patients with tardive dystonia and posttraumatic dystonia and that burke-Fahn-Marsden Dystonia Scale （BFMS） decreased by more than 90%. The improvement of symptoms was progressive along with time. The other 6 patients had slight to moderate improvement. None of them had severe surgery-related complications. One had lead fracture 16 months after surgery and the lead was then evacuated. Conclusions DBS could be an ideal treatment for patients with tardive and posttraumatic dystonia. For patients with perinatal anoxia and diffuse impairment in the ba

关键词： subthalamic nucleus deep brain stimulation secondary dystonia

Ti-5Al-10Cr与Ti-5Al-15Mo合金β晶粒长大动力学研究

在线全文

学校读者我要写书评

暂无评论

热加工工艺 2012年第10期41卷 89-91,95页

作者：李倩王敏赵永庆葛鹏西北工业大学材料学院陕西西安710072 西北有色金属研究院钛合金研究所陕西西安710016

利用burke提出的动力学模型研究了Ti-5Al-10Cr与Ti-5Al-15Mo合金在单相区不同温度、不同保温时间下β晶粒的长大行为。结果表明:在单相区,这两种新型近β钛合金中的β晶粒均随温度的升高和保温时间的延长而长大,且近似符合指数关系。同... 详细信息

利用burke提出的动力学模型研究了Ti-5Al-10Cr与Ti-5Al-15Mo合金在单相区不同温度、不同保温时间下β晶粒的长大行为。结果表明:在单相区,这两种新型近β钛合金中的β晶粒均随温度的升高和保温时间的延长而长大,且近似符合指数关系。同时,计算出两种合金在不同热处理条件下的长大指数与长大激活能。

关键词：近β钛合金热处理 β晶粒生长

在线全文

学校读者我要写书评

暂无评论

丘脑底核电刺激术治疗原发性肌张力障碍

中国微侵袭神经外科杂志 2012年第7期17卷 302-304页

作者：张弨张建国张凯马羽葛明孟凡刚胡文瀚杨岸超首都医科大学附属北京天坛医院神经外科 100050

目的观察双侧丘脑底核(STN)脑深部电刺激(DBS)治疗原发性肌张力障碍的疗效。方法回顾性分析8例接受双侧STN-DBS的原发性肌张力障碍病人的临床资料。分别在术前和术后1、3、6个月进行burke-Fahn-Marsden肌张力障碍评分(BFMDRS)和帕金森... 详细信息

目的观察双侧丘脑底核(STN)脑深部电刺激(DBS)治疗原发性肌张力障碍的疗效。方法回顾性分析8例接受双侧STN-DBS的原发性肌张力障碍病人的临床资料。分别在术前和术后1、3、6个月进行burke-Fahn-Marsden肌张力障碍评分(BFMDRS)和帕金森病综合评分量表(UPDRS),计算两项评分改善率,评价治疗效果。结果 BFMDRS和UPDRS评分的改善率:术后1个月其均值分别为47%和48%,术后3个月为69%和73%,术后6个月为75%和79%。结论 STN-DBS可有效改善原发性肌张力障碍病人的症状,术后疗效稳定。STN是DBS治疗原发性肌张力障碍的理想靶点。

关键词：肌张力障碍,原发性脑深部电刺激丘脑底核