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| 1 | High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa显示文摘It has been reported that ACE2 is the main host cell receptor of 2019-nCoV and plays a crucial role in the entry of virus into the cell to cause the final infection. To investigate the potential route of 2019-n Cov infection on the mucosa of oral cavity, bulk RNA-seq profiles from two public databases including The Cancer Genome Atlas(TCGA) and Functional Annotation of The Mammalian Genome Cap Analysis of Gene Expression(FANTOM5 CAGE) dataset were collected. RNA-seq profiling data of 13 organ types with para-carcinoma normal tissues from TCGA and 14 organ types with normal tissues from FANTOM5 CAGE were analyzed in order to explore and validate the expression of ACE2 on the mucosa of oral cavity. Further, single-cell transcriptomes from an independent data generated in-house were used to identify and confirm the ACE2-expressing cell composition and proportion in oral cavity. The results demonstrated that the ACE2 expressed on the mucosa of oral cavity. Interestingly, this receptor was highly enriched in epithelial cells of tongue. Preliminarily, those findings have explained the basic mechanism that the oral cavity is a potentially high risk for 2019-nCoV infectious susceptibility and provided a piece of evidence for the future prevention strategy in dental clinical practice as well as daily life. | Hao Xu Liang Zhong Jiaxin Deng Jiakuan Peng Hongxia Dan Xin Zeng Taiwen Li Qianming Chen | 2020 | International Journal of Oral Science2020,12,1: | 69 |
| 2 | Clinical characteristics of 24 asymptomatic infections with COVID-19 screened among close contacts in Nanjing,China显示文摘Previous studies have showed clinical characteristics of patients with the 2019 novel coronavirus disease(COVID-19)and the evidence of person-to-person transmission.Limited data are available for asymptomatic infections.This study aims to present the clinical characteristics of 24 cases with asymptomatic infection screened from close contacts and to show the transmission potential of asymptomatic COVID-19 virus carriers.Epidemiological investigations were conducted among all close contacts of COVID-19 patients(or suspected patients)in Nanjing,Jiangsu Province,China,from Jan 28 to Feb 9,2020,both in clinic and in community.Asymptomatic carriers were laboratory-confirmed positive for the COVID-19 virus by testing the nucleic acid of the pharyngeal swab samples.Their clinical records,laboratory assessments,and chest CT scans were reviewed.As a result,none of the 24 asymptomatic cases presented any obvious symptoms while nucleic acid screening.Five cases(20.8%)developed symptoms(fever,cough,fatigue,etc.)during hospitalization.Twelve(50.0%)cases showed typical CT images of ground-glass chest and 5(20.8%)presented stripe shadowing in the lungs.The remaining 7(29.2%)cases showed normal CT image and had no symptoms during hospitalization.These 7 cases were younger(median age:14.0 years;P=0.012)than the rest.None of the 24 cases developed severe COVID-19 pneumonia or died.The median communicable period,defined as the interval from the first day of positive nucleic acid tests to the first day of continuous negative tests,was 9.5 days(up to 21 days among the 24 asymptomatic cases).Through epidemiological investigation,we observed a typical asymptomatic transmission to the cohabiting family members,which even caused severe COVID-19 pneumonia.Overall,the asymptomatic carriers identified from close contacts were prone to be mildly ill during hospitalization.However,the communicable period could be up to three weeks and the communicated patients could develop severe illness.These results highlighted the importance of close contact tracing and longitudinally surveillance via virus nucleic acid tests.Further isolation recommendation and continuous nucleic acid tests may also be recommended to the patients discharged. | Zhiliang Hu Ci Song Chuanjun Xu Guangfu Jin Yaling Chen Xin Xu Hongxia Ma Wei Chen Yuan Lin Yishan Zheng Jianming Wang Zhibin Hu Yongxiang Yi Hongbing Shen | 2020 | Science China(Life Sciences)2020,63,5: | 77 |
| 3 | A new method for detecting line spectrum of ship-radiated noise using Duffing oscillator显示文摘A detection scheme for line spectrum of ship-radiated noise is proposed using Duffing oscillator. The chaotic trajectory of Duffing oscillator is analyzed and the state equation of the system is improved to detect weak periodic signals in different frequencies. According to the simulation results, the phase transforms of Duffing oscillator are sensitive to periodic signals and immune to the random noise and the periodic interference signals which have larger angular frequency difference from the referential signal. By employing Lyapunov exponents in the field of detection as the criteria for chaos, the phase transforms of dynamic behaviors in quantity are successfully determined. Meanwhile, the threshold value in critical state has been evaluated more accurately. Based on the phase transforms of Duffing oscillator, a new method for detecting line spectrum of ship-radiated noise is given. Three types of ship-radiated noise signals are analyzed and the values of line spectrum are acquired successfully by this method. The experimental results show that this method has high sensitivity and high resolution. | ZHENG SiYi GUO HongXia LI YaAn WANG BingHe ZHANG PengYi | 2007 | Chinese Science Bulletin2007,52,14: | 21 |
| 4 | Fatty liver diseases,bile acids,and FXR显示文摘The prevalence of nonalcoholic fatty liver disease(NAFLD) worldwide has increased at an alarming rate,which will likely result in enormous medical and economic burden.NAFLD presents as a spectrum of liver diseases ranging from simple steatosis,nonalcoholic steatohepatitis(NASH),fibrosis,cirrhosis,and even to hepatocellular carcinoma(HCC).A comprehensive understanding of the mechanism(s) of NAFLD-to-NASH transition remains elusive with various genetic and environmental susceptibility factors possibly involved.An understanding of the mechanism may provide novel strategies in the prevention and treatment to NASH.Abnormal regulation of bile acid homeostasis emerges as an important mechanism to liver injury.The bile acid homeostasis is critically regulated by the farnesoid X receptor(FXR) that is activated by bile acids.FXR has been known to exert tissue-specific effects in regulating bile acid synthesis and transport.Current investigations demonstrate FXR also plays a principle role in regulating lipid metabolism and suppressing inflammation in the liver.Therefore,the future determination of the molecular mechanism by which FXR protects the liver from developing NAFLD may shed light to the prevention and treatment of NAFLD. | Yan Zhu Hongxia Liu Min Zhang Grace L.Guo | 2016 | Acta Pharmaceutica Sinica B2016,6,5: | 20 |
| 5 | Bronchial Artery Embolization for Hemoptysis: A Retrospective Observational Study of 344 Patients显示文摘 | Hongxia Shao Junping Wu Qi Wu Xin Sun Li Li Zhiheng Xing Hongfen Sun | 2015 | Chinese Medical Journal2015,,1: | 20 |
| 6 | Effects of dietary arginine levels on growth performance,body composition, serum biochemical indices and resistance ability against ammonia-nitrogen stress in juvenile yellow catfish(Pelteobagrus fulvidraco)显示文摘This experiment was conducted to investigate the effects of dietary arginine levels on growth performance, body composition, serum biochemical indices and resistance ability against ammonia-nitrogen stress in juvenile yellow catfish(Pelteobagrus fulvidraco). Five isonitrogenous and isolipidic diets(42%protein and 9% lipid) were formulated to contain graded levels of arginine(2.44%, 2.64%, 2.81%, 3.01% and3.23% of diet), by supplementing L-Arginine HCI. Seven hundred juvenile yellow catfish with an initial average body weight of 1.13 ± 0.02 g were randomly divided into 5 groups with 4 replicates of 35 fish each and each group was fed one of the diets. After 56 d feeding, fish were exposed to 100 mg/L of ammonia-nitrogen for 72 h. The results showed that weight gain(WG) and specific growth rate(SGR) in2.64% and 2.81% groups were significantly higher than those in 3.23% group(P < 0.05). The feed conversation ratio(FCR) in 2,64%, 2,81% and 3.01% groups was significantly decreased when compared with3,23% group. The protein efficiency ratio(PER) in 2.64% group was significantly higher than that in 2.44%and 3.23% groups(P < 0.05). The condition factor(CF) of fish was significantly higher in 2.81% group than that in 2,44% group(P < 0.05). Dietary arginine levels had no significant effect on hepatosomatic index(HSI), viscerosomatic index(VSI), and whole-body dry matter, crude protein, crude lipid, ash contents, as well as serum total protein(TP), triglyceride(TG), glucose(GLU), urea nitrogen(UN) contents and aspartate aminotransferase(AST), alanine aminotransferase(ALT) activities(P> 0.05). After the fish were challenged to ammonia-nitrogen for 72 h, their cumulative mortality rate in 2.81% group was significantly lower than that in 2.44% group(P < 0.05). The results suggested that dietary arginine level at 2.81%could optimize anti-ammonia-nitrogen stress ability of juvenile yellow catfish and a level of 3.23%arginine seemed to depress the growth performance of fish and decreased their tolerance to the ammonia-nitrogen stress under current study. A quadratic regression analysis based on WG indicated that the optimal dietary arginine requirement of juvenile yellow catfish was estimated to be 2.74% of the diet(6.45% of dietary protein) under current culture conditions. | Qiming Chen Hongxia Zhao Yanhua Huang Junming Cao Guoxia Wang Yuping Sun Yongjuan Li | 2016 | Animal Nutrition2016,,3: | 19 |
| 7 | Microbialite of anoxic condition from Permian-Triassic transition in Guizhou,China显示文摘Spherical microfossils are present in the Hindeodus parvus zone of the Lower Triassic in Ziyun,Guizhou Province. They generally range from 0.15 to 0.30 mm across,with micritic wall and filled by micro-sparry calcites,and are evenly scattered in micritic matrix. Their abundance makes the rock as-signed to microbialites. The accompanied organisms include ostracods and algal mat,but no gastro-pods or bivalves. Presence of small (<7 μm) pyrite framboids indicates that this bed formed in anoxic conditions. In some sections,this bed is overlain and underlain by tidal-flat micritic limestone with microgastropods and small burrows. Occurrence only in deposits on reef top indicates that the micro-bial organism was benthic,and needed sunlight in life. The size of the microbial fossil exceeds that of any bacteria or cyanobacteria. Thus,it does not belong to these two phyla. It may belong to lower green algae,and is assigned to a new species in a new genus,Ziyunosphaeridium sinensis gen. et sp. nov. Up to now,the rocks described as microbialites from the Permian-Triassic transition include six types: (1) porous micritic limestone such as that descried from Japan by Sano and Nakashima (1997),(2) limestone with rich globular microfossils such as that described from the Nanpanjiang Basin in China by Lehrmann (1999),(3) dendroidal limestone such as that described from the vicinity of Chongqing by Kershaw et al. (1999),(4) spherical microbial limestone adapted to anoxic environments described from Ziyun,Guizhou reported in this paper,(5) limestone with cyanobacterial fossils such as that described by Wang et al. (2005),and (6) stromatolites. All these microbialites are not reefs in the proper sense,and the argument that Permian reef ecosystems extended into the Mesozoic is incorrect. | WU YaSheng JIANG HongXia YANG Wan FAN JiaSong | 2007 | Science China Earth Sciences2007,50,7: | 18 |
| 8 | Macrophagic CD146 promotes foam cell formation and retention during atherosclerosis显示文摘 | Yongting Luo Hongxia Duan Yining Qian Liqun Feng Zhenzhen Wu Fei Wang Jing Feng Dongling Yang Zhihai Qin Xiyun Yan | 2017 | Cell Research2017,27,3: | 18 |
| 9 | Photodynamic therapy guidelines for the management of oral leucoplakia显示文摘With recent developments in photosensitizers and light delivery systems,topical 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) has become the fourth alternative therapeutic approach in the management of oral leucoplakia (OLK) due to its minimally invasive nature,efficacy,and low risk of systemic side effects and disfigurement.This report presents step-by-step guidelines for applying topical ALA-PDT in the management of OLK based on both the clinical experience of the authors and a systematic review of the current literature.Studies using protocols with standardized parameters and randomized clinical trials at multiple centres with adequate sample sizes and both interim and long-term follow-ups are needed before universally applicable guidelines can be produced in this field. | Qianming Chen Hongxia Dan Fan Tang Jiongke Wang Xiaoying Li Junxin Cheng Hang Zhao Xin Zeng | 2019 | International Journal of Oral Science2019,11,2: | 18 |
| 10 | Crustal evolution of the Shiwandashan area in South China:Zircon U-Pb-Hf isotopic records from granulite enclaves in Indo-Sinian granites显示文摘标明日期的 U-Pb 在东南的 Guangxi 省从 Shiwandashan 区域在 Jiuzhou peraluminous 花岗石从 metasedimentary granulite 被外国领地包围的土地在锆石上结合了 Hf 同位素分析,华南在这份报纸被介绍。结果证明这些 granulite 被外国领地包围的土地的 protoliths 主要由有一座山峰的碎屑状的材料在 822 妈变老的 Neo-Mesoproterozoic (5641061 妈) 组成。这些材料可能从在 Rodinian Supercontinent 的 Neoproterozoic 决裂期间是 emplaced 的火的岩石被导出。辅助沉积包括 Paleoproterozoic (17782227 妈) ,有最旧的 U-Pb 的甚至 Meso-Paleoarchean 材料在 3551 | ZHAO Liang GUO Feng FAN WeiMing LI ChaoWen QIN XiaoFeng LI HongXia | 2010 | Chinese Science Bulletin2010,55,19: | 18 |
| 11 | Nickel accumulation and its effects on the survival rate of Spodoptera litura Fabricius under continuous nickel stress显示文摘The artificial diets mixed with various concentrations of nickel were offered to the larvae of the phytophagous insect Spodoptera litura Fabricius for 3 generations. Nickel accumulations in the 6th instar larvae, pupae and newly emerged adults of the corresponding generations of S. litura were investigated by Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), and the effects of nickel accumulations on the survival rate of S. litura were also evaluated by individual rearing. The results showed that nickel accumulated in the 6th instar larvae, pupae and adults of S. litura, and the accu- mulated nickel in all the tested developmental stages within a generation increased with the increase of the nickel doses in the treated diets and showed significant dose-dependent relationship with the nickel doses in the artificial diets. The results also indicated that the nickel accumulations in the 6th instar larvae, pupae, and newly emerged adults from the 3rd generation were higher than those from the 2nd generation, which were also higher than those from the 1st generation. Nickel concentrations in pupae and adults were significantly lower than those in larvae, which indicated that the excessive nickel might be excreted during metamorphosis. Furthermore, larval survival rate, pupation rate and eclosion rate of S. litura in the tested three generations all decreased with the increase of the nickel doses in the treated diets. | SUN HongXia SHU YingHua TANG WenCheng WANG Qi ZHOU Qiang ZHANG GuRen | 2007 | Chinese Science Bulletin2007,52,14: | 16 |
| 12 | Increasing trend of prevalence of infertility in Beijing显示文摘 | Zhang Hongxia Wang Shuyu Zhang Songwen Wang Tao Deng Xiaohong | 2014 | Chinese Medical Journal2014,,4: | 16 |
| 13 | Centroid-based semi-fragile audio watermarking in hybrid domain显示文摘Many previous (semi-) fragile audio watermarking schemes adopt binary images as watermarks, which reduce the security of watermarking systems. On the other hand, the content-based or feature-based second generation digital watermarking has limited applicability, and its partial feature points may be damaged by watermarking operations and various common signal processing. To overcome these problems, in this paper, a novel centroid-based semi-fragile audio watermarking scheme in hybrid domain is proposed. The theoretical lower limit of signal to noise ratio (SNR) for objective evaluation of the imperceptibility of watermarked audio signal is deduced, and the watermark embedding capacity and the tamper detection ability are theoretically analyzed. In the proposed scheme, first, the centroid of each audio frame is computed, then Hash function is performed on the obtained centroid to get the watermark, after that, the audio sub-band which carries centroid of audio frame is performed with discrete wavelet transform (DWT) and discrete cosine transform (DCT), and finally the encrypted watermark bits are embedded into the hybrid domain. Theoretical analysis and experimental results show that the proposed scheme is inaudible and applicable to different types of audio signals. Furthermore, its ability of tamper detection and tolerance against common signal processing operations are excellent. Comparing with the existing schemes, the proposed scheme can effectively authenticate the veracity and integrity of audio content, and greatly expand the applicability of the content-based audio watermarking scheme. | WANG HongXia & FAN MingQuan School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China | 2010 | Science China(Information Sciences)2010,53,3: | 14 |
| 14 | Field evaluation of effects of transgenic cry1Ab/cry1Ac,cry1C and cry2A rice on Cnaphalocrocis medinalis and its arthropod predators显示文摘The impacts of transgenic Bt rice on target pests and their predators need to be clarified prior to the commercialization of Bt rice.In this study,the percentages of folded leaves of three transgenic Bt rice lines and non-transgenic parental rice line caused by Cnaphalocrocis medinalis were studied over two successive growing seasons.In addition,the population densities,relative abundance and population dynamics of C.medinalis and four species of its natural arthropod predators were investigated at three sites in China.The results showed that rice line significantly affected the percentages of folded leaves and population densities of C.medinalis larvae.Significantly higher percentages of folded leaves were observed on the non-transgenic rice compared with the three transgenic Bt rice on most sampling dates.Significantly higher densities of C.medinalis larvae and higher relative abundance of C.medinalis within phytophages were found on non-transgenic rice compared with three transgenic Bt rice at different sites across the study period.The population dynamics of C.medinalis larvae were significantly affected by rice line,rice line×sampling date,rice line×year,rice line×sampling date×year.However,there was little,if any,significant difference in the relative abundance,population density and population dynamics of the four arthropod predators between the three Bt rice lines and non-transgenic rice.The results of this study indicate that the Bt toxin in transgenic Bt rice can effectively suppress the occurrence of C.medinalis,but has no significant effects on the occurrence of the four predatory arthropod species. | XU XueLiang HAN Yu WU Gang CAI WanLun YUAN BenQi WANG Hui LIU FangZhou WANG ManQun HUA HongXia | 2011 | Science China(Life Sciences)2011,54,11: | 14 |
| 15 | Phytolith records of the climate change since the past 15000 years in the middle reach of the Yangtze River in China显示文摘基于 ^ 啜 14 ^ C 标明日期和核心沉积调查, phytolith 记录被采用重建在在中间的 Jianghan 平原的 paleovegetation 和古气候长江到达。识别的 Phytoliths 被分配进 21 描述得好的 morphotypes 并且把组划分了成四(Poaceae,蕨纲植物,具球果、阔叶) 。和温暖索引的 phytolith 集合(我 ^ 潜水艇 w ^) 被划分成 18 个生态的地区,它在过去的 15000 年期间在长江的中间的活动范围反映与气候变化有关的完全的植被历史。根据有从石笋, peatland ,诺思大西洋深海的沉积,华中的黄土高原,和阿拉伯语海的 paleoclimatic 指示物的 phytolith 记录的关联沉积,八个气候的阶段被识别包括的上次冰川的最大值( LGM )( 20-14.8 cal kaBP ),持续冰川的消失( LDG )( 14.8-11.9 cal kaBP ),在早 Holocene ( 11.9-8 cal kaBP )的低温度的阶段, Holocene 最佳( 8-4.9 cal kaBP ), Holocene Katathermal ( 4.9-1.1 cal kaBP ),中世纪的温暖时期( M 自从 LDG,象 Bolling-Allerod 温暖的间隔,更旧的 Dryas, Inter-Allerod 冷时期,和更年轻的 Dryas 那样的气候的事件,和八个霍洛辛·邦德事件(B1-8 ) 被识别了。我们的结果证明在研究区域的气候的进化与印度夏天有一个强壮的连接季风( SW 季风),亚洲夏天季风( SE 季风),和在诺思大西洋的 Holocene 事件同时,它可能显示太阳的可变性在一百年、千年的规模影响地球表面气候系统[出版摘要] | Yansheng GU Hanlin WANG Xianyu HUANG Hongxia PENG Junhua HUANG | 2012 | Frontiers of Earth Science2012,6,1: | 14 |
| 16 | Interlayer interactions in anisotropic atomically thin rhenium diselenide显示文摘在这个工作,我们学习夹层声子颤动模式, layer-numberdependent 原子地薄的金来 diselenide 的光 bandgap,和各向异性的光致发光(PL ) 系列(ReSe 2) 第一次。在 ReSe 2 的 ultralow 频率夹层拉曼系列和解决极化的高频率拉曼系列允许它的层数字和水晶取向的鉴定。而且, PL 大小显示出材料的各向异性的光排放紧张,它的 bandgap 在单层在体积从 1.26 eV 增加到 1.32 eV。拉曼模式和 PL 系列的层数字依赖的学习揭示相对弱的货车 der Waals 相互作用并且二维(2D ) 在原子地薄的 ReSe 2 的量监禁。在单层和多层的 ReSe 2 的吸引人的各向异性的夹层相互作用和悦耳的光转变的试验性的观察在在在红外线附近的光谱工作的各向异性的 optoelectronic 设备的发展为这材料的进一步的探索建立基础,它为在光通讯并且红外线的察觉到的许多应用是重要的。 | Huan Zhao Jiangbin Wu Hongxia Zhong Qiushi Guo Xiaomu Wang Fengnian Xia Li Yang Pingheng Tan Han Wang | 2015 | Nano Research2015,8,11: | 14 |
| 17 | Mechanical properties of gangue-containing aluminosilicate based cementitious materials显示文摘High performance aluminosilicate based cementitious materials were produced using calcined gangue as one of the majorraw materials. The gangue was calcined at 500°C. The main constituent was calcined gangue, fly ash and slag, while alkali-silicatesolutions were used as the diagenetic agent. The structure of gangue-containing aluminosilicate based cementitious materials wasstudied by the methods of IR, NMR and SEM. The results show that the mechanical properties are affected by the mass ratio betweenthe gangue, slag and fly ash, the kind of activator and additional salt. For 28-day curing time, the compressive strength of the samplewith a mass proportion of 2:1:1 (gangue: slag: fly ash) is 58.9 MPa, while the compressive strength of the sample containing 80wt%gangue can still be up to 52.3 MPa. The larger K+ favors the formation of large silicate oligomers with which Al(OH)4? prefers to bind.Therefore, in Na-K compounding activator solutions more oligomers exist which result in a stronger compressive strength of alumino-silicate-based cementitious materials than in the case of Na-containing activator. The reasons for this were found through IR and NMRanalysis. Glauber’s salt reduces the 3-day compressive strength of the paste, but increases its 7-day and 28-day compressive strengths. | Huajian Li Henghu Sun Xuejun Xiao Hongxia Chen | 2006 | Journal of University of Science and Technology Beijing2006,13,2: | 14 |
| 18 | Application of next-generation sequencing technology to precision medicine in cancer: joint consensus of the Tumor Biomarker Committee of the Chinese Society of Clinical Oncology显示文摘Next-generation sequencing(NGS) technology is capable of sequencing millions or billions of DNA molecules simultaneously.Therefore, it represents a promising tool for the analysis of molecular targets for the initial diagnosis of disease, monitoring of disease progression, and identifying the mechanism of drug resistance. On behalf of the Tumor Biomarker Committee of the Chinese Society of Clinical Oncology(CSCO) and the China Actionable Genome Consortium(CAGC), the present expert group hereby proposes advisory guidelines on clinical applications of NGS technology for the analysis of cancer driver genes for precision cancer therapy. This group comprises an assembly of laboratory cancer geneticists, clinical oncologists, bioinformaticians,pathologists, and other professionals. After multiple rounds of discussions and revisions, the expert group has reached a preliminary consensus on the need of NGS in clinical diagnosis, its regulation, and compliance standards in clinical sample collection. Moreover, it has prepared NGS criteria, the sequencing standard operation procedure(SOP), data analysis, report, and NGS platform certification and validation. | Xuchao Zhang Zhiyong Liang Shengyue Wang Shun Lu Yong Song Ying Cheng Jianming Ying Weiping Liu Yingyong Hou Yangqiu Li Yi Liu Jun Hou Xiufeng Liu Jianyong Shao Yanhong Tai Zheng Wang Li Fu Hui Li Xiaojun Zhou Hua Bai Mengzhao Wang You Lu Jinji Yang Wenzhao Zhong Qing Zhou Xuening Yang Jie Wang Cheng Huang Xiaoqing Liu Xiaoyan Zhou Shirong Zhang Hongxia Tian Yu Chen Ruibao Ren Ning Liao Chunyan Wu Zhongzheng Zhu Hongming Pan Yanhong Gu Liwei Wang Yunpeng Liu Suzhan Zhang Tianshu Liu Gong Chen Zhimin Shao Binghe Xu Qingyuan Zhang Ruihua Xu Lin Shen Yilong Wu | 2019 | Cancer Biology & Medicine2019,16,1: | 14 |
| 19 | PREPARATIOPREPARATION OF 1-OCTENE BY ETHYLENE TETRAMERIZATION WITH HIGH SELECTIVITY显示文摘Two novel PNP ligands have been synthesized and characterized by 1H-NMR, elemen- tal analysis, and mass spectra. In combination with Cr(Ⅲ ) and cocatalyst MAO, they generate active catalytic systems that tetramerize ethylene with both high catalytic activity and high selectivity to produce 1-octene. The results show that these catalyst sys- tems are able to catalyze ethylene tetramerization, with high catalytic activity up to 0.89×106 g/mol Cr.h, and the selectivity of C8 in products is 72.52%, and the percentage of 1-olefins in the C8 cut is 97.87%. | JIANG Tao CHEN Hongxia NING Yingnan CHEN Wei | 2006 | Chinese Science Bulletin2006,51,5: | 13 |
| 20 | Ethylene tetramerization with a highly active and long-lifetime trinuclear diphenylphosphinoamine/Cr(III)/MAO catalyst显示文摘The synthesis and characterization of a novel trinuclear diphosphinoamine ligand 2 are reported. The ligand combined with Cr(III), activated with methylaluminoxane, lead to highly active and long-lifetime catalytic systems for the tetramerization of ethylene to form 1-octene. The effects of reaction temperature, reaction pressure, molar ratio of Al/Cr and bis(diphenylphosphino)amine/Cr on the catalytic activity and product selectivity were studied. Compared with its mononuclear analogue 1, ligand 2 showed a higher catalytic activity and longer lifetime for ethylene tetramerization in the presence of methylaluminoxane as cocatalyst. High molecular weight polyethylene was generated as a by-product with extremely broad molecular weight distributions. | JIANG Tao TAO YiQing GAO XiangLu MAO GuoLiang CHEN HongXia CAO ChenGang NING YingNan | 2012 | Chinese Science Bulletin2012,57,13: | 12 |