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B/Al/Ga-MOR分子筛催化甲醇/二甲醚羰基化反应机理的理论计算研究
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作者 任鹏宇 刘卓 +4 位作者 权燕红 郭军军 马宏 武建兵 王永钊 《燃料化学学报(中英文)》 EI CAS CSCD 北大核心 2024年第3期323-334,共12页
采用DFT计算比较分析了B、Al和Ga分别同晶取代MOR分子筛八元环侧袋T3位点及十二元环孔道T4位点时甲醇及二甲醚羰基化反应机制的共性及差异。研究发现,CO插入甲氧基生成乙酰基的反应遵循S_(N)2机制,且为羰基化反应过程中的决速步;473 K下... 采用DFT计算比较分析了B、Al和Ga分别同晶取代MOR分子筛八元环侧袋T3位点及十二元环孔道T4位点时甲醇及二甲醚羰基化反应机制的共性及差异。研究发现,CO插入甲氧基生成乙酰基的反应遵循S_(N)2机制,且为羰基化反应过程中的决速步;473 K下,无论甲醇或二甲醚为原料,生成的乙酰基更倾向于与甲醇中的CH3O作用生成乙酸甲酯;T3位点具有更好的羰基化择形性,而T4位点上更倾向于发生由三甲基氧鎓离子生成芳烃导致催化剂失活的副反应。与Al-MOR相比,在T3位点引入B和Ga会导致羰基化反应能垒的升高,降低其催化性能;而在T4位点引入B和Ga(尤其是B)则可大幅提升其生成三甲基氧鎓离子的能垒,抑制芳烃生成过程,提升催化剂稳定性。本工作有助于认识MOR分子筛不同孔道内酸性位点发生同晶取代时催化羰基化反应机制的差异,为调控设计高效MOR沸石催化剂提供一定的理论支撑。 展开更多
关键词 羰基化 甲醇 二甲醚 B/Al/Ga-mor分子筛 DFT计算 反应机理
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Comparison study on measurement of rail weld joint between inertial reference method and multi-point chord reference method
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作者 Yifan Shi Yuan Wang +1 位作者 Xiaozhou Liu Ping Wang 《Railway Sciences》 2024年第1期69-83,共15页
Purpose – Straightness measurement of rail weld joint is of essential importance to railway maintenance. Dueto the lack of efficient measurement equipment, there has been limited in-depth research on rail weld joint ... Purpose – Straightness measurement of rail weld joint is of essential importance to railway maintenance. Dueto the lack of efficient measurement equipment, there has been limited in-depth research on rail weld joint with a5-m wavelength range, leaving a significant knowledge gap in this field.Design/methodology/approach – In this study, the authors used the well-established inertial referencemethod (IR-method), and the state-of-the-art multi-point chord reference method (MCR-method). Two methodshave been applied in different types of rail straightness measurement trollies, respectively. These instrumentswere tested in a high-speed rail section within a certain region of China. The test results were ultimatelyvalidated through using traditional straightedge and feeler gauge methods as reference data to evaluate the railweld joint straightness within the 5-m wavelength range.Findings – The research reveals that IR-method and MCR-method produce reasonably similar measurementresults for wavelengths below 1 m. However, MCR-method outperforms IR-method in terms of accuracy forwavelengths exceeding 3 m. Furthermore, it was observed that IR-method, while operating at a slower speed,carries the risk of derailing and is incapable of detecting rail weld joints and low joints within the track.Originality/value – The research compare two methods’ measurement effects in a longer wavelength rangeand demonstrate the superiority of MCR-method. 展开更多
关键词 Rail weld joint Inertial reference method Short-wavelength irregularities Multi-point chord reference method 5-m wavelength range
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Defining the We-map Reference Frames and Providing Mathematical Expressions for Transformation Relations
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作者 WANG Xiaolong YAN Haowen +2 位作者 WANG Zhuo MA Wenjun YU Yitao 《Journal of Geodesy and Geoinformation Science》 CSCD 2024年第3期76-88,共13页
We-map is an interactive mobile map that can be easily communicated and applied on personal electronic devices,such as personal computers and mobile phones.Therefore,the study of direction systems and coordinate syste... We-map is an interactive mobile map that can be easily communicated and applied on personal electronic devices,such as personal computers and mobile phones.Therefore,the study of direction systems and coordinate systems is critical,and exploring reference frames is essential in direction and coordinate systems.Despite its significance,existing research on We-map lacks specific solutions for the exploration of reference frames is indispensable for the establishment of accurate direction and coordinate systems.In this paper,we endeavor to address this gap by elucidating the significance of We-map reference frames,defining them with mathematical constraints,summarizing their nature and characteristics,deriving their transformation relationships and representing them through mathematical formulars and equations.Our work contributes to the fundamental theory of We-map and provides valuable systems and support for the mathematical foundation of We-map,map production,and platform development.Ultimately,this research serves to advance the development of We-map. 展开更多
关键词 We-map reference frames spatial direction relation coordinate system
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Pathological and Etiological Aspects of Nephrotic Syndrome at the Niamey General Reference Hospital
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作者 Djibrilla Gani Salamatou Amadou Niaouro Oumarou Ali Diallo 《Open Journal of Nephrology》 2024年第3期340-349,共10页
Introduction: Studies have been conducted on nephrotic syndrome in Niger. The study aimed to determine the histological and etiological aspects of nephrotic syndrome. Patients and Method: This was a retrospective stud... Introduction: Studies have been conducted on nephrotic syndrome in Niger. The study aimed to determine the histological and etiological aspects of nephrotic syndrome. Patients and Method: This was a retrospective study from February 1st, 2018 to January 31st, 2024. All patients with nephrotic syndrome who underwent renal biopsy were included. Samples were analyzed at the anatomy-cytology pathology laboratory of the Faculty of Medicine in Dakar (Senegal). The variables studied included clinical, biological, histological and etiological characteristics. Data were analyzed using Excel 2013 and Epi-info 7.2.0 software. Results: The study included 119 patients with nephrotic syndrome. Prevalence of nephrotic syndrome was 11.24%. The male-to-female ratio was 2.25:1. The mean age at diagnosis was between 34.5 ± 18.84 years. Edema was the reason for admission in 40.34% of cases. The nephrotic syndrome was impure in 63.86% of cases. Nine histological lesions were identified. Focal and segmental glomerulosclerosis (40.09%), minimal change disease (23.53%), membranous nephropathy (13.45%), diabetic nephropathy (10.92%), membranous proliferative glomerulonephritis (3.36%), acute glomerulonephritis (3.36%), glomerular thrombotic microangiopathy (2.52%), non-IgA mesengial proliferative glomerulonephritis (1.68%) and amyloidosis (0.84%). Nephrotic syndrome was primary in 57.98% of cases. Secondary etiologies were dominated by diabetes (11.76%), followed by hepatitis B virus (9.24%), lupus, lymphoma, malaria, syphilis, cryoglobulinemia, sickle cell disease and HIV. Conclusion: Future studies should investigate the causes of glomerulopathy secondary to chronic tubulointerstitial lesions. 展开更多
关键词 Nephrotic Syndrome Anatomopathology Niamey General reference Hospital
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Review of Two Years of Surgical Activities of the General Surgery Department of the Reference Health Center of Commune I of Bamako Mali
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作者 Tounkara Cheickna Cisse Amadou Beydi +5 位作者 Samake Hamidou Diarra Issaka Sanogo Modibo Diarra Bogoba Doumbia Seydou Yena Sadio 《Surgical Science》 2024年第4期195-206,共12页
The objectives of this work were to evaluate the surgical activities carried out in the general surgery department of the Reference Health Center of Commune I of Bamako, to describe the sociodemographic characteristic... The objectives of this work were to evaluate the surgical activities carried out in the general surgery department of the Reference Health Center of Commune I of Bamako, to describe the sociodemographic characteristics of the operated patients, to determine the main pathologies encountered and to evaluate qualitatively the result of the treatment. In order to improve performance, and the quality of care, and to identify common pathologies in the surgical department, we undertook a retrospective study on surgical activities from January 2009 to December 2010. At the end of this study, out of 474 men and 187 women (equal sex ratio 2.53);we were able to determine the frequency of surgical pathologies. Farmers, housewives and pupils/students were the most represented with 25.9% respectively;20% and 13.3%. The most frequently observed pathologies were wall hernia (44.8%), prostate adenoma (12%) and acute appendicitis (10.5%). The average length of hospitalization was 3.43 days. Infectious complications affected 25 patients (3.8% of cases) and a death rate of 0.45% (i.e. 3 patients). The average cost of care was 53,500 FCFA. Indeed, the reality of surgical practice in health centers was not the same because of the level of skills of practicing surgeons. 展开更多
关键词 Assessment Surgical Activities 2 Years reference Health Center of Commune I BAMAKO
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RPLP0/TBP are the most stable reference genes for human dental pulp stem cells under osteogenic differentiation
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作者 Daniel B Ferreira Leticia M Gasparoni +1 位作者 Cristiane F Bronzeri Katiucia B S Paiva 《World Journal of Stem Cells》 SCIE 2024年第6期656-669,共14页
BACKGROUND Validation of the reference gene(RG)stability during experimental analyses is essential for correct quantitative real-time polymerase chain reaction(RT-qPCR)data normalisation.Commonly,in an unreliable way,... BACKGROUND Validation of the reference gene(RG)stability during experimental analyses is essential for correct quantitative real-time polymerase chain reaction(RT-qPCR)data normalisation.Commonly,in an unreliable way,several studies use genes involved in essential cellular functions[glyceraldehyde-3-phosphate dehydro-genase(GAPDH),18S rRNA,andβ-actin]without paying attention to whether they are suitable for such experimental conditions or the reason for choosing such genes.Furthermore,such studies use only one gene when Minimum Information for Publication of Quantitative Real-Time PCR Experiments guidelines recom-mend two or more genes.It impacts the credibility of these studies and causes dis-tortions in the gene expression findings.For tissue engineering,the accuracy of gene expression drives the best experimental or therapeutical approaches.We cultivated DPSCs under two conditions:Undifferentiated and osteogenic dif-ferentiation,both for 35 d.We evaluated the gene expression of 10 candidates for RGs[ribosomal protein,large,P0(RPLP0),TATA-binding protein(TBP),GAPDH,actin beta(ACTB),tubulin(TUB),aminolevulinic acid synthase 1(ALAS1),tyro-sine 3-monooxygenase/tryptophan 5-monooxygenase activation protein,zeta(YWHAZ),eukaryotic translational elongation factor 1 alpha(EF1a),succinate dehydrogenase complex,subunit A,flavoprotein(SDHA),and beta-2-micro-globulin(B2M)]every 7 d(1,7,14,21,28,and 35 d)by RT-qPCR.The data were analysed by the four main algorithms,ΔCt method,geNorm,NormFinder,and BestKeeper and ranked by the RefFinder method.We subdivided the samples into eight subgroups.RESULTS All of the data sets from clonogenic and osteogenic samples were analysed using the RefFinder algorithm.The final ranking showed RPLP0/TBP as the two most stable RGs and TUB/B2M as the two least stable RGs.Either theΔCt method or NormFinder analysis showed TBP/RPLP0 as the two most stable genes.However,geNorm analysis showed RPLP0/EF1αin the first place.These algorithms’two least stable RGs were B2M/GAPDH.For BestKeeper,ALAS1 was ranked as the most stable RG,and SDHA as the least stable RG.The pair RPLP0/TBP was detected in most subgroups as the most stable RGs,following the RefFinfer ranking.CONCLUSION For the first time,we show that RPLP0/TBP are the most stable RGs,whereas TUB/B2M are unstable RGs for long-term osteogenic differentiation of human DPSCs in traditional monolayers. 展开更多
关键词 Dental pulp stem cells reference gene Housekeeping gene Endogenous gene Osteogenic differentiation RefFinder
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Equalization Reconstruction Algorithm Based on Reference Signal Frequency Domain Block Joint for DTMB-Based Passive Radar
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作者 Shuai Ma Zeqi Yang +2 位作者 Hua Zhang Yiheng Liu Xiaode Lyu 《Journal of Beijing Institute of Technology》 EI CAS 2024年第1期41-53,共13页
Channel equalization plays a pivotal role within the reconstruction phase of passive radar reference signals.In the context of reconstructing digital terrestrial multimedia broadcasting(DTMB)signals for low-slow-small... Channel equalization plays a pivotal role within the reconstruction phase of passive radar reference signals.In the context of reconstructing digital terrestrial multimedia broadcasting(DTMB)signals for low-slow-small(LSS)target detection,a novel frequency domain block joint equalization algorithm is presented in this article.From the DTMB signal frame structure and channel multipath transmission characteristics,this article adopts a unconventional approach where the delay and frame structure of each DTMB signal frame are reconfigured to create a circular convolution block,facilitating concurrent fast Fourier transform(FFT)calculations.Following equalization,an inverse fast Fourier transform(IFFT)-based joint output and subsequent data reordering are executed to finalize the equalization process for the DTMB signal.Simulation and measured data confirm that this algorithm outperforms conventional techniques by reducing signal errors rate and enhancing real-time processing.In passive radar LSS detection,it effectively suppresses multipath and noise through frequency domain equalization,reducing false alarms and improving the capabilities of weak target detection. 展开更多
关键词 passive radar frequency domain equalization reference signal reconstruction digital terrestrial multimedia broadcasting(DTMB)
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Reference Interval of Thyroidal Function of Women in the Early,Middle and Late Pregnancy in Jingzhou City,Hubei Province
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作者 Hongying WU Kai DING 《Medicinal Plant》 2024年第5期1-3,共3页
[Objectives]To study the reference value of thyroid function in healthy women of childbearing age during different pregnancies(early,middle and late pregnancy)in Jingzhou City.[Methods]362 healthy women of childbearin... [Objectives]To study the reference value of thyroid function in healthy women of childbearing age during different pregnancies(early,middle and late pregnancy)in Jingzhou City.[Methods]362 healthy women of childbearing age during different pregnancies(early,middle and late pregnancy)were selected as the study group,and 360 non-pregnant women were selected as the control group.Serum thyroid hormone levels in the two groups were detected,and the reference value was expressed as the median(M)and 95%confidence interval(CI).On this basis,the chart of changing trend of thyroid hormone in the early,middle and late pregnancy were plotted.[Results]Compared with the control group,FT3,TT4,TT3,FT4and TSH in the early,middle and late pregnancy were significantly different in the study group(P<0.05).In the study group,there were significant differences in the early,middle and late pregnancy(P<0.05).[Conclusions]This trend chart has certain reference value in the screening,diagnosis and treatment of thyroid diseases in healthy women of childbearing age during different pregnancies(early,middle and late pregnancy)in Jingzhou City of Hubei Province. 展开更多
关键词 EARLY middle and late pregnancy Thyroid function reference value Thyroid hormone
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A Reference Vector-Assisted Many-Objective Optimization Algorithm with Adaptive Niche Dominance Relation
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作者 Fangzhen Ge Yating Wu +1 位作者 Debao Chen Longfeng Shen 《Intelligent Automation & Soft Computing》 2024年第2期189-211,共23页
It is still a huge challenge for traditional Pareto-dominatedmany-objective optimization algorithms to solve manyobjective optimization problems because these algorithms hardly maintain the balance between convergence... It is still a huge challenge for traditional Pareto-dominatedmany-objective optimization algorithms to solve manyobjective optimization problems because these algorithms hardly maintain the balance between convergence and diversity and can only find a group of solutions focused on a small area on the Pareto front,resulting in poor performance of those algorithms.For this reason,we propose a reference vector-assisted algorithmwith an adaptive niche dominance relation,for short MaOEA-AR.The new dominance relation forms a niche based on the angle between candidate solutions.By comparing these solutions,the solutionwith the best convergence is found to be the non-dominated solution to improve the selection pressure.In reproduction,a mutation strategy of k-bit crossover and hybrid mutation is used to generate high-quality offspring.On 23 test problems with up to 15-objective,we compared the proposed algorithm with five state-of-the-art algorithms.The experimental results verified that the proposed algorithm is competitive. 展开更多
关键词 Many-objective optimization evolutionary algorithm Pareto dominance reference vector adaptive niche
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超级黑胶唱盘New Reference有多硬核? THORENS多能仕总裁Gunter Kurten先生告诉你
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作者 小路 《视听前线》 2024年第9期78-79,共2页
德国THORENS(多能仕),自1883年创立以来,已拥有超过140年的辉煌历史,是全球首屈一指的黑胶唱盘品牌之一。值此140周年庆典之际,THORENS于2023年隆重推出了新一代的旗舰产品——New Reference超级黑胶唱盘。
关键词 旗舰产品 reference 黑胶 TH NS 辉煌历史
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Design of MC9 Test Equipment for Inertial Reference System
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作者 ZHANG Haowen GUAN Hongyang WANG Shuangjia 《International Journal of Plant Engineering and Management》 2024年第2期115-128,共14页
Inertial reference system is one of the airborne equipment.According to the requirements of SAE ARP4754A Guidelines for Development of Civil Aircraft and Systems,MC9 equipment qualification test is needed to verify th... Inertial reference system is one of the airborne equipment.According to the requirements of SAE ARP4754A Guidelines for Development of Civil Aircraft and Systems,MC9 equipment qualification test is needed to verify that the inertial reference system can perform reservation function under specified service conditions.That is,the inertial reference system shall pass certain environmental tests specified in DO⁃160G.Some tests are faced with the problem that the test equipment should have the function requirements of isolation protection and load simulation.Therefore,a kind of test equipment which can provide isolation protection and simulate load function in the test is designed. 展开更多
关键词 inertial reference system MC9 isolation protection simulated load
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一个传奇的品牌,一个经典的系列 KEF与TheReference系列的故事
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作者 家祺 《视听前线》 2024年第1期2-7,共6页
回顾2023年,KEF的产品又再斩获众多不同定位、不同类型的各种Hi-Fi音响奖项。在更新MAT技术后,KEF全线新Meta系列在音质方面的提升是备受肯定的。其中最受瞩目的自然是KEF当家的Reference系列了。Reference (参考)系列作为KEF产品线中... 回顾2023年,KEF的产品又再斩获众多不同定位、不同类型的各种Hi-Fi音响奖项。在更新MAT技术后,KEF全线新Meta系列在音质方面的提升是备受肯定的。其中最受瞩目的自然是KEF当家的Reference系列了。Reference (参考)系列作为KEF产品线中一个非常重要的高端系列,历经多次变革,至今依然是KEF产品线当中最受发烧友欢迎的系列。它不仅是嫡传KEF每个时期应用于旗舰级先进技术的产品,更是KEF最新技术的普及应用和向下移植的承载者。这个刚刚迈过第50个年头的经典系列在这么多年来能够持续获得发烧友和媒体的喜爱实属不易,这个系列是如何一步一步成为经典的?我们来回顾一下KEF这个品牌与参考系列的发展。 展开更多
关键词 KEF 旗舰级 reference 承载者 产品线 音质 普及应用 品牌
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一切皆有可能 测试Consonance Reference CDS8音乐播放器
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作者 克里斯蒂安·拜尔 Yilan(编译) Ivy Li(编译) 《视听前线》 2024年第10期35-37,共3页
以前,我从未想过听CD会过时,但在无载体媒体时代,情况已经如此。幸运的是,一群执着的音响发烧友还在坚持。ORERA Consonance Re horee a OPERA Consonance Reference CDS8这款CD、数码流播放器,不仅可以播放CD,而且它是以非常高的水准... 以前,我从未想过听CD会过时,但在无载体媒体时代,情况已经如此。幸运的是,一群执着的音响发烧友还在坚持。ORERA Consonance Re horee a OPERA Consonance Reference CDS8这款CD、数码流播放器,不仅可以播放CD,而且它是以非常高的水准来播放CD,名副其实的好产品,可以与Advance Acoustics、Creek、AVM等这些品牌的产品齐名。 展开更多
关键词 音乐播放器 音响发烧友 一切皆有可能 无载体 reference CDS AVM
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Selection of reference genes for RT-qPCR analysis of Phenacoccus solenopsis(Hemiptera: Pseudococcidae) sex-dimorphic development 被引量:3
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作者 ZHENG Lu-ying ZHANG Zhi-jun +6 位作者 ZHANG Jin-ming LI Xiao-wei HUANG Jun LIN Wen-cai LI Wei-di LI Chuan-ren LU Yao-bin 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2019年第4期854-864,共11页
Mealybugs, such as Phenacoccus solenopsis, are highly sexually dimorphic. Winged adult males present such remarkable morphological differences from females that, to the untrained eye, conspecific adults of both sexes ... Mealybugs, such as Phenacoccus solenopsis, are highly sexually dimorphic. Winged adult males present such remarkable morphological differences from females that, to the untrained eye, conspecific adults of both sexes of P. solenopsis may be considered as two different insect species. A method to investigate sex-dimorphic mechanisms is by evaluating gene expression using RT-qPCR. However, the accuracy and consistency of this technique depend on the reference gene(s) selected. In this study, we analyzed the expression of 10 candidate reference genes in male and female P. solenopsis at different development stages, using common algorithms including the ?Ct method, NormFinder, geNorm, BestKeeper, and a web-based analysis tool, RefFinder. The results showed that EF1-β, RP-L32 and RP-18 S were selected as the most stable genes by both the ?Ct method and NormFinder; TUB-α was the most stable gene identified by BestKeeper; and RP-L40 and RP-L32 were the most stable genes ranked by geNorm. RefFinder, a comprehensive analysis software, ranked the ten genes and determined EF1-β and RP-L32 as the most suitable reference genes for the various developmental stages in male and female P. solenopsis. Furthermore, the two most suitable reference genes were validated by examining expression of the juvenile hormone acid O-methytransferase(JHAMT) gene. Results of the validation portion of the study showed that JHAMT expression was sex-biased towards males and exhibited a dynamic and classic expression pattern among the P. solenopsis developmental stages. The results can help further our knowledge on the molecular mechanisms underlying sexual dimorphic development in P. solenopsis. 展开更多
关键词 Phenacoccus SOLENOPSIS RT-QPCR sexual dimorphic DEVELOPMENT reference GENE GENE stability
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高温水蒸气热处理对H-MOR分子筛骨架铝稳定性的影响 被引量:3
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作者 刘冲 徐舒涛 +1 位作者 魏迎旭 刘中民 《石油学报(石油加工)》 EI CAS CSCD 北大核心 2023年第6期1231-1241,共11页
H-MOR分子筛是目前已发现的分子筛类催化剂中最具活性和选择性的二甲醚羰基化反应催化剂。在实际工业应用中,H-MOR分子筛往往不可避免地发生脱铝现象,导致分子筛Bronsted酸量降低,从而降低分子筛的二甲醚羰基化反应活性。通过一维和二... H-MOR分子筛是目前已发现的分子筛类催化剂中最具活性和选择性的二甲醚羰基化反应催化剂。在实际工业应用中,H-MOR分子筛往往不可避免地发生脱铝现象,导致分子筛Bronsted酸量降低,从而降低分子筛的二甲醚羰基化反应活性。通过一维和二维固体核磁共振实验研究了高温(700℃)、不同水蒸气处理时间下H-MOR分子筛的物化性质及骨架铝的稳定性。随着水蒸气处理时间的增加,H-MOR分子筛脱铝程度加剧,Bronsted酸量下降。H-MOR存在四配位铝物种Al(Ⅳ)-1、Al(Ⅵ)-2及六配位铝物种Al(Ⅵ)。高温水蒸气处理后,出现新的铝物种Al(Ⅴ)信号。H-MOR在经过水蒸气处理后,骨架四配位铝物种Al(Ⅳ)-1先转变为扭曲四配位铝物种Al(Ⅳ)-2,接着转变为五配位铝物种Al(Ⅴ)和六配位铝物种Al(Ⅵ),进一步转变为铝的氧化物。 展开更多
关键词 H-mor 固体核磁共振 水蒸气处理 骨架铝 稳定性
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Low-level lead exposure effects on spatial reference memory and working memory in rats 被引量:1
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作者 Xinhua Yang Ping Zhou Yonghui Li 《Neural Regeneration Research》 SCIE CAS CSCD 2009年第1期72-76,共5页
BACKGROUND: Studies have demonstrated that lead exposure can result in cognitive dysfunction and behavior disorders. However, lead exposure impairments vary under different experimental conditions. OBJECTIVE: To det... BACKGROUND: Studies have demonstrated that lead exposure can result in cognitive dysfunction and behavior disorders. However, lead exposure impairments vary under different experimental conditions. OBJECTIVE: To detect changes in spatial learning and memory following low-level lead exposure in rats, in Morris water maze test under the same experimental condition used to analyze lead exposure effects on various memory types and learning processes. DESIGN AND SETTING: The experiment was conducted at the Animal Laboratory, Institute of Psychology, Chinese Academy of Science between February 2005 and March 2006. One-way analysis of variance (ANOVA) and behavioral observations were performed. MATERIALS: Sixteen male, healthy, adult, Sprague Dawley rats were randomized into normal con-trol and lead exposure groups (n = 8). METHODS: Rats in the normal control group were fed distilled water, and those in the lead exposure group were fed 250 mL of 0.05% lead acetate once per day. At day 28, all rats performed the Morris water maze test, consisting of four phases: space navigation, probe test, working memory test, and visual cue test. MAIN OUTCOME MEASURES: Place navigation in the Morris water maze was used to evaluate spatial learning and memory, probe trials for spatial reference memory, working memory test for spatial working memory, and visual cue test for non-spatial cognitive function. Perkin-Elmer Model 300 Atomic Absorption Spectrometer was utilized to determine blood lead levels in rats. RESULTS: (1) In the working memory test, the time to reach the platform remained unchanged between the control and lead exposure groups (F(1,1) = 0.007, P = 0.935). A visible decrease in escape latencies was observed in each group (P = 0.028). However, there was no significant difference between the two groups (F(1,1) = 1.869, P = 0.193). The working memory probe test demonstrated no change between the two groups in the time spent in the target quadrant during the working memory probe test (F(1,1) = 1.869, P = 0.193). However, by day 4, differences were observed in the working memory test (P 〈 0.01). (2) Multivariate repetitive measure and ANOVA in place navigation presented no significant difference between the two groups (F(1,1) = 0.579, P = 0.459). (3) Spatial probe test demonstrated that the time to reach the platform was significantly different between the two groups (F(1,1) = 4.587, P = 0.048), and one-way ANOVA showed no significant difference in swimming speed between the two groups (F(1,1) = 1.528, P = 0.237). (4) In the visual cue test, all rats reached the platform within 15 seconds, with no significant difference (F(1,1) = 0.579, P = 0.459). (5) During experimentation, all rats increased in body mass, but there was no difference between the two groups (F(1,1) = 0.05, P = 0.943). At day 28 of 0.05% lead exposure, the blood lead level was 29.72 μg/L in the lead exposure group and 5.86 μg/L in the control group (P 〈 0.01). CONCLUSION: The present results revealed low-level lead exposure significantly impaired spatial reference memory and spatial working memory, but had no effect on spatial learning. 展开更多
关键词 LEAD spatial learning reference memory working memory
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热处理工艺对14Cr1MoR钢组织性能及腐蚀行为的影响 被引量:2
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作者 王储 孙绍广 +2 位作者 高强 刘晨希 贾春堂 《压力容器》 北大核心 2023年第6期7-14,共8页
采用扫描电镜、透射电镜和电化学工作站,分析了控轧+回火、淬火+回火、正火+回火不同热处理工艺对14Cr1MoR钢显微组织、力学性能和腐蚀行为的影响。结果表明:控轧+回火和正火+回火后,试验钢的显微组织由多边形铁素体和贝氏体回火组织构... 采用扫描电镜、透射电镜和电化学工作站,分析了控轧+回火、淬火+回火、正火+回火不同热处理工艺对14Cr1MoR钢显微组织、力学性能和腐蚀行为的影响。结果表明:控轧+回火和正火+回火后,试验钢的显微组织由多边形铁素体和贝氏体回火组织构成,但相比例不同。淬火+回火后,试验钢的显微组织为回火索氏体,该热处理工艺下的14Cr1MoR钢室温和高温强度最高,韧性最佳。耐蚀性能方面,淬火+回火态试验钢最佳;其次为正火+回火态试验钢;控轧+回火态试验钢最差。 展开更多
关键词 14Cr1mor 热处理工艺 腐蚀行为 显微组织 索氏体
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μ-阿片受体激动剂通过MOR/AKT/Slug途径促进膀胱癌循环肿瘤细胞的形成:一项包含随机对照试验的综合研究
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作者 汪晓强 张松 +12 位作者 金迪 罗佳美 施郁淼 张艺琪 吴玲玲 宋彦龄 苏殿三 潘志英 陈海戈 曹明 杨朝勇 俞卫锋 田婕 《癌症》 CAS 2023年第12期640-660,共21页
背景与目的μ-阿片受体激动剂(μ-opioid receptor agonists,MOs)是膀胱癌(bladder cancer,BC)患者手术和慢性疼痛治疗过程中不可或缺的麻醉镇痛药。MOs是否会影响膀胱癌的进展和转移仍未阐明。本研究关注MOs对BC循环肿瘤细胞(circulati... 背景与目的μ-阿片受体激动剂(μ-opioid receptor agonists,MOs)是膀胱癌(bladder cancer,BC)患者手术和慢性疼痛治疗过程中不可或缺的麻醉镇痛药。MOs是否会影响膀胱癌的进展和转移仍未阐明。本研究关注MOs对BC循环肿瘤细胞(circulating tumor cell,CTC)形成的影响,旨在提供潜在的治疗靶点。方法利用不同的临床前模型来确定MORAs对BC进展的影响。利用新型免疫捕获微流控芯片分析MORAs是否影响小鼠模型和临床BC患者的CTC数量。生物信息学分析、全转录组测序和分子生物学方法被用于研究潜在机制。结果血行转移和原位BC小鼠模型显示,MORAs治疗后肿瘤转移明显增加。在小鼠模型和临床试验患者中,MORAs治疗后检测到间质和/或上皮细胞CTC数量明显增加。从机制上看,MORAs通过激活MOR/PI3K/AKT/Slug信号通路促进CTC的形成,并促进BC细胞发生上皮–间质转化(epithelialmesenchymal transition,EMT),而敲除MOR、Slug或阻断PI3K可抑制EMT过程和CTC的形成。结论MOs通过促进CTC的形成来促进BC的转移。在MO治疗期间,可针对EMT-CTC轴采取预防措施,以抑制BC患者相关的肿瘤转移或复发。 展开更多
关键词 μ阿片受体激动剂 AKT 膀胱癌 循环肿瘤细胞 上皮间质转化 微流控芯片 mor PI3K SLUG
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The China Seismological Reference Model project 被引量:4
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作者 LianXing Wen Sheng Yu 《Earth and Planetary Physics》 CAS CSCD 2023年第5期521-532,共12页
The importance of developing high-resolution seismic models to improve understanding of tectonic processes and enhance seismic hazard mitigation programs,along with the rapid expansion of seismic coverage in China,cal... The importance of developing high-resolution seismic models to improve understanding of tectonic processes and enhance seismic hazard mitigation programs,along with the rapid expansion of seismic coverage in China,called for a seismological reference model to be established in China.The China Seismological Reference Model(CSRM)project was initiated by the National Natural Science Foundation of China with two primary goals:(1)the CSRM would serve as a primary source for the current state of seismological research in China,and(2)the seismic data and constraints used to construct the CSRM would be used as a backbone open-access cyberinfrastructure for future research in seismology.The CSRM project was also intended to promote data exchange and scientific collaboration in seismology in China.Accordingly,two parallel efforts of the project are being pursued:(1)construction of the CSRM,and(2)development of a CSRM product center.The CSRM is jointly constrained by various types of seismic constraints extracted from the seismic data recorded at 4511 seismic stations in continental China following a top-down approach,with the seismic structures in the shallower part of the Earth constrained first.Construction of the CSRM involves three preparation steps:(1)building datasets of various seismic constraints from the seismic data,(2)developing a method to incorporate the constraints of surface wave observations from regional earthquakes into the inversion of the seismic structure,and(3)constructing high-resolution pre-CSRM seismic models of the velocity structure in the shallow crust and the Pn-velocity structure in the uppermost mantle.In the final process,the CSRM will be constructed by jointly inverting all the seismic constraints using the pre-CSRM models as starting models or a priori structures.The CSRM product center(http://chinageorefmodel.org)archives and distributes three types of products:CSRM models,the Level 1 original seismic data used to extract seismic constraints in the construction of the CSRM,and Level 2 data on the seismic constraints derived from the Level 1 data and the inferred earthquake parameters in the construction of the CSRM.The CSRM product center has archived 141 TB of Level 1 data from 1120 permanent broadband stations in the China Seismic Network Center and 3391 temporary stations from various institutions and data centers around the world,as well as 140 GB of Level 2 data on various seismic constraints and inferred event parameters from the construction of the CSRM.The CSRM is expected to provide significant insights into the composition and tectonic dynamics in continental China and to enhance the capability of various seismic hazard mitigation programs in China from near real-time rapid determination of earthquake parameters to an earthquake early warning system.The CSRM could also provide guidance for focuses in future seismological research and the design of future active and passive seismic experiments in China.Several focuses are suggested for future seismological research in China,along with the building of a national cyberinfrastructure to sustain and expand the operations of the CSRM project. 展开更多
关键词 China Seismological reference Model seismic structure seismic hazard TECTONICS continental China
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14Cr1MoR钢的热处理工艺创新实践
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作者 李样兵 李杰 +3 位作者 龙杰 柳付芳 袁锦程 吴艳阳 《热加工工艺》 北大核心 2023年第22期147-150,154,共5页
结合某钢厂订货产品结构和热处理装备特点,针对当前14Cr1MoR钢热处理工艺中存在的低温冲击性能波动和成本偏高等瓶颈问题,在试验室开展14Cr1MoR钢高温退火+淬火+回火的新型热处理工艺创新。结果表明:采用本文所述工艺所得板厚1/2处常温... 结合某钢厂订货产品结构和热处理装备特点,针对当前14Cr1MoR钢热处理工艺中存在的低温冲击性能波动和成本偏高等瓶颈问题,在试验室开展14Cr1MoR钢高温退火+淬火+回火的新型热处理工艺创新。结果表明:采用本文所述工艺所得板厚1/2处常温拉伸性能控制水平与现行工艺水平相当,板厚1/2处低温冲击韧性总体更优,组织也更为均匀、细化,实现吨钢降低热处理成本350元左右,为企业创新发展提供技术支撑。 展开更多
关键词 14Cr1mor 热处理工艺 冲击韧性 组织 析出物
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