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高速列车铜基摩擦材料的氧化行为
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作者 肖金坤 李天天 +2 位作者 鲍霆峰 陈娟 张超 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第7期2260-2274,共15页
高速列车铜基摩擦材料在制动过程中,由于摩擦热的产生和耗散,会发生循环氧化。研究铜基摩擦材料在300、400、500、600和700℃下等温氧化50h的氧化行为。结果表明:铜基摩擦材料的氧化行为呈现多阶段特征;Cu、Fe的氧化与氧的扩散共同控制... 高速列车铜基摩擦材料在制动过程中,由于摩擦热的产生和耗散,会发生循环氧化。研究铜基摩擦材料在300、400、500、600和700℃下等温氧化50h的氧化行为。结果表明:铜基摩擦材料的氧化行为呈现多阶段特征;Cu、Fe的氧化与氧的扩散共同控制着低温氧化过程,而石墨的氧化在500℃之后占主导作用;Cu的氧化首先形成Cu_(2)O纳米团簇,然后生成CuO纳米线,最后依次转变为细小的和粗大的等轴晶;氧化温度的升高会促进Fe_(2)O_(3)纳米片的生长和致密化;Cu氧化物由于体积膨胀较大,逐渐将Fe氧化物覆盖;石墨烧蚀后形成的连通孔为内氧化提供氧气扩散通道;材料表面氧化层的形成使得表面硬度提高。 展开更多
关键词 铜基摩擦材料 等温氧化动力学 氧化行为 表面形貌
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The effects of stereotactic body radiotherapy on peripheral natural killer and CD3~+CD56~+ NKT-like cells in patients with hepatocellular carcinoma
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作者 tian-tian li Jing Sun +4 位作者 Quan Wang Wen-Gang li Wei-Ping He Rui-Chuang Yang Xue-Zhang Duan 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS CSCD 2021年第3期240-250,共11页
Background: Both natural killer(NK) and CD3+CD56+ natural killer T(NKT)-like cells play critical roles in the antitumor response. This study aimed to explore the effects of stereotactic body radiotherapy(SBRT) on peri... Background: Both natural killer(NK) and CD3+CD56+ natural killer T(NKT)-like cells play critical roles in the antitumor response. This study aimed to explore the effects of stereotactic body radiotherapy(SBRT) on peripheral NK and NKT-like cells in patients with hepatocellular carcinoma(HCC), and to identify possible surface markers on these cells that correlate with the prognosis. Methods: Twenty-five HCC patients were prospectively enrolled in our study, and 10 healthy individuals were served as healthy controls. Flow cytometry was used to determine the counts and the percentages of peripheral NK and NKT-like cells, cells with certain receptors, and cells with intracellular interferon-γand TNF-α secretion at different time points, including time points of prior to SBRT, at post-SBRT, and 3-month and 6-month after treatment. The Kaplan-Meier method with the log-rank test was applied for survival analysis. Results: The peripheral NKT-like cells was increased at post-SBRT. Meanwhile, elevated levels of inhibitory receptors and reduced levels of activating receptors of NK cells were also observed in NK cells at post-SBRT, but the levels was not significantly different at 3-month and 6-month as compared with the baseline levels. Lower percentage of NKp30+ NK cells before SBRT and higher percentage of CD158b + NK cells after SBRT were associated with poor progression-free survival. In addition, higher percentage of CD3+CD56+ NKT-like cells was associated with a higher overall survival rate in HCC patients. Conclusions: SBRT has an apparent effect on both peripheral NK and CD3+ CD56+ NKT-like cells. Lower percentage of NKp30 + NK cells before SBRT and higher percentage of CD158b + NK cells after SBRT are correlated with poor patients' PFS. Higher percentage of CD3+ CD56+ NKT-like cells is associated with higher OS in HCC patients. 展开更多
关键词 Nature killer cells Hepatocellular carcinoma Nature killer T-like cells Stereotactic body radiotherapy
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In situ regulating intimately connected heterostructure by decomposition of solid solution oxides toward high-efficient water oxidation
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作者 Shao-Fei Zhang Xiao-Lu Yin +7 位作者 Jin Wang Jian-li Kang tian-tian li Jin-Feng Sun Yong-Qiang Meng Jian-Jiang Wang Dian-Long Wang Kai-Qiang Qin 《Rare Metals》 SCIE EI CAS CSCD 2024年第4期1557-1569,共13页
Heterogeneous interfaces produced by interdomain interactions on a nanoscale performs a crucial role in boosting the properties of an electrocatalyst toward oxygen evolution reaction(OER)process.Herein,a series of dua... Heterogeneous interfaces produced by interdomain interactions on a nanoscale performs a crucial role in boosting the properties of an electrocatalyst toward oxygen evolution reaction(OER)process.Herein,a series of dual-phase electrodes with intimately connected heterointerfaces are prepared by in situ decomposing solid solution oxide of Ni_(x)Co_(y)Fe_(100-x-y)O,which grew on Ni foam massively via an ultrafast combustion approach.Particularly,with high-reaction kinetics caused by the reduction treatment at 450℃,the less electronegative Fe and Co are more oxyphilic than Ni,which facilitated their co-exsolution and formation of CoFe_2O_4/NiO oxide with enriched oxygen vacancies.Benefiting from the nanoporous framework,heterojunction structure,and oxygen defects,the self-supporting electrodes present rapid charge/mass transmission and provide abundant active sites for OER.The optimized sample(R-SNCF4.5)shows low overpotentials of 226 and 324 mV at 10 and100 mA·cm^(-2),a small Tafel slope(46.7 mV·dec^(-1)),and excellent stability.The assembled R-SNCF4.5//Pt/C/NF electrolyzer demonstrates continuous electrolysis over 50 h at a current density of 10 mA·cm^(-2),under 1.51 V.Density functional theory(DFT)calculations verify that the strong electronic modulation plays a critical part in the CoFe_2O_4/NiO hybrid by lowering the energy barriers for the ratedetermining steps,and Fe sites are the most active OER sites. 展开更多
关键词 Rapid combustion Decomposition of solid solution oxide Dual-phase heterostructure Oxygen evolution reaction Theoretical calculation
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不同手术年龄间歇性外斜视术后双眼视功能的临床观察 被引量:13
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作者 刘育榕 赵林 +2 位作者 李添天 吴晓璇 于健 《国际眼科杂志》 CAS 北大核心 2020年第2期325-327,共3页
目的:探讨不同手术年龄的间歇性外斜视患者术后双眼视功能的恢复情况。方法:选取2016-01/2018-01在我科住院行斜视矫正术的间歇性外斜视患者172例,其中男95例,女77例,年龄3~32岁(平均11.4±1.5)岁。间歇性外斜视患者均为基本型。根... 目的:探讨不同手术年龄的间歇性外斜视患者术后双眼视功能的恢复情况。方法:选取2016-01/2018-01在我科住院行斜视矫正术的间歇性外斜视患者172例,其中男95例,女77例,年龄3~32岁(平均11.4±1.5)岁。间歇性外斜视患者均为基本型。根据手术年龄分为两组:≤9岁组(90例)和>9岁组(82例)。术前和术后1、7d,1、3mo,采用同视机检查双眼视功能,Titmus检查近立体视。结果:≤9岁组患者的同时视功能、融合功能、融合范围、远立体视、近立体视随术后时间的增长恢复效果优于>9岁组患者(P<0.05)。结论:间歇性外斜视患者建议在9岁前手术治疗,尽早手术有利于术后双眼视功能更好地改善。 展开更多
关键词 间歇性外斜视 不同年龄 双眼视功能
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中西医结合治疗外伤性视神经病变疗效评价的Meta分析 被引量:4
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作者 吴琼 周剑 +5 位作者 韦企平 闫晓玲 李甜甜 史航 郑榆美 周晓昱 《国际眼科杂志》 CAS 北大核心 2021年第2期279-284,共6页
目的:系统评价中西医结合治疗外伤性视神经病变(TON)的临床疗效及安全性。方法:通过计算机检索PubMed、Embase、Cochrane Library、中国期刊全文数据库(CNKI)、中国生物医学文献数据库(CBM)、万方数据库、维普数据库自建库至2020-05的... 目的:系统评价中西医结合治疗外伤性视神经病变(TON)的临床疗效及安全性。方法:通过计算机检索PubMed、Embase、Cochrane Library、中国期刊全文数据库(CNKI)、中国生物医学文献数据库(CBM)、万方数据库、维普数据库自建库至2020-05的关于中西医结合与单纯西医治疗TON的随机对照研究,使用Cochrane评价手册对纳入文献进行质量评价,使用RevMan5.3统计软件进行资料提取与Meta分析。结果:共筛选出12篇符合纳入、排除标准的文献;Meta分析结果显示,与单纯西药治疗TON比较,中西医结合治疗有效率更高[RR=1.33,95%CI(1.23~1.45),P<0.001];在改善视力[MD=0.18,95%CI(0.14~0.23),P<0.001]、视野平均缺损[MD=-3.08,95%CI(-5.20~0.96),P=0.004]、视觉诱发电位P100波峰潜时[MD=-9.47,95%CI(-16.37~2.57),P=0.007]以及视觉诱发电位P100波峰振幅[MD=1.44,95%CI(0.22~2.66),P=0.02]上作用更显著。纳入文献有2篇提及不良反应的发生和处理,余10篇均未描述。结论:与单纯西医治疗相比,中西医结合治疗TON的疗效更佳。 展开更多
关键词 中西医结合 外伤性视神经病变 META分析 随机对照试验
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HOTAIR表达水平与结直肠癌患者预后关系的分析
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作者 王柏清 王珏磊 +3 位作者 张宝芹 李甜甜 王超 孙光斌 《世界华人消化杂志》 CAS 2021年第17期984-989,共6页
背景结直肠癌是最常见的恶性肿瘤之一,能够找到早期发现和评估肿瘤预后的生物标志物十分必要.近年来研究发现,HOX转录反义RNA(HOX transcript antisense RNA,HOTAIR)在包括结直肠癌的各种癌症中表达升高,但由于各个研究样本量较小,说服... 背景结直肠癌是最常见的恶性肿瘤之一,能够找到早期发现和评估肿瘤预后的生物标志物十分必要.近年来研究发现,HOX转录反义RNA(HOX transcript antisense RNA,HOTAIR)在包括结直肠癌的各种癌症中表达升高,但由于各个研究样本量较小,说服力不强.目的采用Meta分析的方法对HOTAIR表达水平与结直肠癌患者预后的关系进行探讨.方法通过对Pub Med、Medline、CNKI、CBM和Cochrane图书馆的搜索,检索2020-12发表的有关HOTAIR表达水平与结直肠癌患者预后关系的文献.两名评价员独立进行纳入文献的质量评价和数据提取,计算总生存期(overall survival,OS)的危险比(hazard ratio,HR)以及淋巴结转移(lymph node metastasis,LNM)和远处转移(distant metastasis,DM)的优势比(odds ratios,OR),以评估关联强度.结果符合纳入标准的7篇文献被纳入.其中6篇比较了HOTAIR表达水平与OS的相关性,结果显示两组间差异有统计学意义(OR=2.36,95%CI:1.74-3.19,P<0.05).5篇比较了HOTAIR表达水平与LNM的相关性,两组间差异有统计学意义(OR=4.07,95%CI:1.38-12.0,P<0.05).4篇比较了HOTAIR表达水平与DM的相关性,两组间差异有统计学意义(OR=4.32,95%CI:1.60-11.62,P<0.05).结论结直肠癌组织中HOTAIR的高表达与OS降低和LNM、DM有显著的相关性,提示HOTAIR有可能作为一种判断肿瘤预后的新型生物标志物,对结直肠癌患者的预后监测具有一定的意义. 展开更多
关键词 HOX转录反义RNA HOTAIR 结直肠癌 Meta分析
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长链非编码RNA在胰腺癌发生发展中的作用
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作者 王柏清 王珏磊 +3 位作者 张宝芹 李甜甜 王超 孙光斌 《世界华人消化杂志》 CAS 2022年第6期274-279,共6页
胰腺癌是一种恶性程度很高,诊断和治疗都很困难的消化道恶性肿瘤.近年研究发现,长链非编码RNA(long non-coding RNA,LncRNA)可以通过调控表观遗传修饰、选择性剪接、转录和蛋白质翻译,介导肿瘤的发生、增殖、迁移和转移,在胰腺癌的发生... 胰腺癌是一种恶性程度很高,诊断和治疗都很困难的消化道恶性肿瘤.近年研究发现,长链非编码RNA(long non-coding RNA,LncRNA)可以通过调控表观遗传修饰、选择性剪接、转录和蛋白质翻译,介导肿瘤的发生、增殖、迁移和转移,在胰腺癌的发生发展中发挥着重要作用.本文总结了最新有关LncRNA在胰腺癌发生发展中的研究,以期在胰腺癌的诊治上提供新的临床思路. 展开更多
关键词 长链非编码RNA LncRNA 胰腺癌
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青盲一号方治疗中毒性视神经萎缩的疗效分析 被引量:6
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作者 李甜甜 闫晓玲 +2 位作者 苏艳 韦企平 周剑 《国际眼科杂志》 CAS 北大核心 2020年第1期132-135,共4页
目的:评价青盲一号方治疗中毒性视神经萎缩的临床疗效。方法:分析2013-01/2018-02于北京中医药大学东方医院眼科采用青盲一号方治疗的肝郁血虚型中毒性视神经萎缩患者7例13眼,随访6~24mo,观察治疗前后视力、视野、电生理及视网膜神经纤... 目的:评价青盲一号方治疗中毒性视神经萎缩的临床疗效。方法:分析2013-01/2018-02于北京中医药大学东方医院眼科采用青盲一号方治疗的肝郁血虚型中毒性视神经萎缩患者7例13眼,随访6~24mo,观察治疗前后视力、视野、电生理及视网膜神经纤维层(RNFL)厚度等指标的变化,综合评估青盲一号方的临床疗效。结果:本研究纳入患者中乙胺丁醇中毒者5例10眼,酒精中毒者1例1眼,狂犬疫苗中毒者1例2眼。治疗前4例8眼患者行OCT检查示鼻侧与颞侧RNFL厚度已发生明显薄变,末次随访时各象限厚度仍呈下降趋势。至末次随访时,视力提高≥0.1者4眼(31%),提高0.06~<0.1者2眼(15%),提高0.04~<0.06者1眼(8%),提高0.01~<0.04者4眼(31%),视力无提高者2眼(15%);青盲一号方治疗显效3眼(27%),有效4眼(36%),无效4眼(36%),总有效率为64%。结论:青盲一号方能够延缓视神经萎缩的进展,可在一定程度上改善视功能,发挥视神经保护的作用。 展开更多
关键词 青盲一号方 肝郁血虚证 中毒性视神经萎缩 视神经保护 乙胺丁醇 酒精
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“悬吊法”在胃底固有肌层肿瘤内镜全层切除术中的应用 被引量:1
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作者 王超 王柏清 +2 位作者 李甜甜 王珏磊 孙光斌 《世界华人消化杂志》 CAS 2022年第1期43-48,共6页
背景随着内镜技术的发展,对于起源于固有肌层的胃黏膜下肿瘤(submucosal tumor,SMT)临床医师常采用内镜全层切除术(endoscopic full-thickness resection,EFTR)切除;然而对于胃底黏膜下肿瘤应用传统方法有诸多缺点,应用悬吊法辅助EFTR... 背景随着内镜技术的发展,对于起源于固有肌层的胃黏膜下肿瘤(submucosal tumor,SMT)临床医师常采用内镜全层切除术(endoscopic full-thickness resection,EFTR)切除;然而对于胃底黏膜下肿瘤应用传统方法有诸多缺点,应用悬吊法辅助EFTR可解决传统方法的弊端,对其效果及安全性的临床研究尚不多.目的探讨“悬吊法”在胃底固有肌层肿瘤内镜全层切除术中的应用价值.方法回顾性分析天津市第五中心医院消化内科2017-08/2021-06期间22例胃底固有肌层肿瘤的患者接受EFTR的临床资料.按不同手术方式分为传统EFTR组和改良“悬吊法”+EFTR组.对照组12例患者进行传统EFTR,观察组10例患者进行改良“悬吊法”+EFTR.比较两组方法的手术时间、术中出血量、创面缝合时间、住院时间.结果观察组比对照组患者手术时间、创面缝合时间短,术中出血量少,两组间具有统计学差异(P<0.05).结论“悬吊法”+EFTR可更好地缩短手术时间及创面缝合时间,降低术中出血量,对于治疗胃底固有肌层肿瘤是一种安全的、可行的、有效的方法,适合在临床应用. 展开更多
关键词 胃底 固有肌 黏膜下肿瘤 内镜全层切除术 悬吊法
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经内镜下分次黏膜切除术诊断结肠子宫内膜异位症1例并文献复习
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作者 王超 郑末 +2 位作者 李甜甜 王珏磊 孙光斌 《世界华人消化杂志》 CAS 2021年第9期496-500,共5页
背景子宫内膜异位症是发生于育龄期女性的一种慢性雌激素依赖性疾病,异位内膜可侵犯全身任何部位,结肠子宫内膜异位症发生率低,临床表现不典型,误诊率高.病例简介本文报道了1例因腹泻就诊于消化科内科的患者,通过内镜下分次黏膜切除术(e... 背景子宫内膜异位症是发生于育龄期女性的一种慢性雌激素依赖性疾病,异位内膜可侵犯全身任何部位,结肠子宫内膜异位症发生率低,临床表现不典型,误诊率高.病例简介本文报道了1例因腹泻就诊于消化科内科的患者,通过内镜下分次黏膜切除术(endoscopic piecemeal mucosal resection,EPMR)确诊了结肠子宫内膜异位症,避免了非必要的外科手术.结论应用EPMR大活检或可作为提高结直肠子宫内膜异位症诊断率的一种方法,但尚需大样本量的研究证实. 展开更多
关键词 结肠 子宫内膜异位症 内镜下分次黏膜切除术 大活检
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Within-litter variation in birth weight: impact of nutritional status in the sow 被引量:3
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作者 Tao-lin YUAN Yu-hua ZHU +7 位作者 Meng SHI tian-tian li Na li Guo-yao WU Fuller W.BAZER Jian-jun ZANG Feng-lai WANG Jun-jun WANG 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2015年第6期417-435,共19页
Accompanying the beneficial improvement in litter size from genetic selection for high-prolificacy sows, within-litter variation in birth weight has increased with detrimental effects on post-natal growth and survival... Accompanying the beneficial improvement in litter size from genetic selection for high-prolificacy sows, within-litter variation in birth weight has increased with detrimental effects on post-natal growth and survival due to an increase in the proportion of piglets with low birth-weight. Causes of within-litter variation in birth weight include breed characteristics that affect uterine space, ovulation rate, degree of maturation of oocytes, duration of time required for ovulation, interval between ovulation and fertilization, uterine capacity for implantation and placentation, size and efficiency of placental transport of nutrients, communication between conceptus/fetus and maternal systems, as well as nutritional status and environmental influences during gestation. Because these factors contribute to within-litter variation in birth weight, nutritional status of the sow to improve fetal-placental development must focus on the following three important stages in the reproductive cycle: pre-mating or weaning to estrus, early gestation and late gestation. The goal is to increase the homogeneity of development of oocytes and conceptuses, decrease variations in conceptus development during implantation and placentation, and improve birth weights of newborn piglets. Though some progress has been made in nutritional regulation of within-litter variation in the birth weight of piglets, additional studies, with a focus on and insights into molecular mechanisms of reproductive physiology from the aspects of maternal growth and offspring development, as well as their regulation by nutrients provided to the sow, are urgently needed. 展开更多
关键词 Within-litter variation PIG Mortality MORBIDITY Growth Sow nutrition
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Fabrication of bimetallic Cu–Zn adsorbents with high dispersion by using confined space for gas adsorptive separation
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作者 Yu-Chao Wang tian-tian li +2 位作者 li Huang Xiao-Qin liu lin-Bing Sun 《Frontiers of Chemical Science and Engineering》 SCIE EI CSCD 2022年第11期1623-1631,共9页
The number of active components and their dispersion degree are two key factors affecting the performance of adsorbents.Here,we report a simple but efficient strategy for dispersing active components by using a confin... The number of active components and their dispersion degree are two key factors affecting the performance of adsorbents.Here,we report a simple but efficient strategy for dispersing active components by using a confined space,which is formed by mesoporous silica walls and templates in the as-prepared SBA-15(AS).Such a confined space does not exist in the conventional support,calcined SBA-15,which does not contain a template.The Cu and Zn precursors were introduced to the confined space in the AS and were converted to CuO and ZnO during calcination,during which the template was also removed.The results show that up to 5 mmol·g^(–1) of CuO and ZnO can be well dispersed;however,severe aggregation of both oxides takes place in the sample derived from the calcined SBA-15 with the same loading.Confined space in the AS and the strong interactions caused by the abundant hydroxyl groups are responsible for the dispersion of CuO and ZnO.The bimetallic materials were employed for the adsorptive separation of propene and propane.The samples prepared from the as-prepared SBA-15 showed superior performance to their counterparts from the calcined SBA-15 in terms of both adsorption capacity of propene and selectivity for propene/propane. 展开更多
关键词 bimetallic adsorbents confined space mesoporous silica PROPENE propane separation
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Quasi-solid-state solar rechargeable capacitors based on in-situ Janus modified electrode for solar energy multiplication effect
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作者 Peng Chen tian-tian li +1 位作者 Guo-Ran li Xue-Ping Gao 《Science China Materials》 SCIE EI CSCD 2020年第9期1693-1702,共10页
Solar energy is one of the most appealing clean energies to replace fossil fuel.However,the low power output is the bottleneck that hinders the effective usage of solar energy.Herein,we propose quasi-solid-state solar... Solar energy is one of the most appealing clean energies to replace fossil fuel.However,the low power output is the bottleneck that hinders the effective usage of solar energy.Herein,we propose quasi-solid-state solar rechargeable capacitors for solar energy multiplication effect and effective application based on Janus modified electrode.The power output of solar energy could be magnified by an integrated unit,which consists of the hydrogel electrolyte,asymmetrically lyophilic/lyophobic Janus joint electrode,and efficient perovskite solar cells.Benefiting from the unique Janus structure,the quasi-solid-state device is capable of achieving outstanding solar energy conversion,storage and utilization with large power output of 500 mW cm^-2,which is about 50 times higher than that of conventional solar cells. 展开更多
关键词 solar energy power multiplier solar rechargeable capacitors perovskite quasi-solid-state
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Effect of the Nanoparticle Functionalization on the Cavitation and Crazing Process in the Polymer Nanocomposites
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作者 Yan-Long Luo tian-tian li +4 位作者 Bin li Xian-ling Chen Zhen-Yang Luo Yang-Yang Gao li-Qun Zhang 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2021年第2期249-257,I0008,共10页
The nanoparticle(NP) functionalization is an effective method for enhancing their compatibility with polymer which can influence the fracture property of the polymer nanocomposites(PNCs). This work aims to further und... The nanoparticle(NP) functionalization is an effective method for enhancing their compatibility with polymer which can influence the fracture property of the polymer nanocomposites(PNCs). This work aims to further understand the cavitation and crazing process, hoping to uncover the fracture mechanism on the molecular level. By adopting a coarse-grained molecular dynamics simulation, the fracture energy of PNCs first increases and then decreases with increasing the NP functionalization degree α while it shows a continuous increase with increasing the interaction εpA between polymer and modified beads. The bond orientation degree is first characterized which is referred to as the elongation. Meanwhile, the stress by polymer chains is gradually reduced with increasing the α or the εpA while that by NPs is enhanced.Furthermore, the percentage of stress by polymer chains first increases and then decreases with increasing the strain while that by NPs shows a contrast trend. Moreover, the number of voids is quantified which first increases and then decreases with increasing the strain which reflects their nucleation and coalescence process. The voids prefer to generate from the polymer-NP interface to the polymer matrix with increasing α o r εpA.As a result, the number of voids first increases and then decreases with increasing α while it continuously declines with the εpA. In summary, our work provides a clear understanding on how the NP functionalization influences the cavitation and crazing process during the fracture process. 展开更多
关键词 Nanoparticle functionalization Cavitation and crazing Polymer nanocomposites Molecular dynamics simulation
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基于聚醚胺(PEA)动态交联网络的多重响应性表面褶皱图案 被引量:2
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作者 张轶洁 李甜甜 +2 位作者 马晓东 印杰 姜学松 《高分子学报》 SCIE CAS CSCD 北大核心 2021年第1期61-68,I0003,共9页
刺激响应性表面图案赋予了材料动态可调的表面性能,是智能材料领域研究的热点,然而如何通过简单有效的方法构建这类动态表面图案也是该领域的难点.本文将动态硼酸酯键和光可逆二聚基团引入到聚醚胺(PEA)交联网络中,通过双层褶皱体系构... 刺激响应性表面图案赋予了材料动态可调的表面性能,是智能材料领域研究的热点,然而如何通过简单有效的方法构建这类动态表面图案也是该领域的难点.本文将动态硼酸酯键和光可逆二聚基团引入到聚醚胺(PEA)交联网络中,通过双层褶皱体系构建一系列具有光和湿度刺激响应性表面褶皱图案.在365 nm紫外光照和加热的条件下,蒽基团(AN)的光二聚与硼酸键的形成使得上表层聚醚胺模量变大,产生微米级表面褶皱图案;在254 nm紫外光照射或水蒸气作用下,聚醚胺网络解交联,表面褶皱图案消失;利用光化学时空分辨的特性,通过光掩膜板光照还可以制备多层次动态表面褶皱图案.这种多重刺激响应性表面褶皱图案为构建智能聚合物表面提供了新思路,在传感和防伪等领域具有潜在的应用前景. 展开更多
关键词 褶皱 聚醚胺 刺激响应 硼酸酯 光可逆二聚
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Measuring the Interfacial Thickness of Immiscible Polymer Blends by Nano-probing of Atomic Force Microscopy
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作者 tian-tian li Si-Bo Cheng +3 位作者 lian-Fang Feng Xue-Ping Gu Cai-liang Zhang Guo-Hua Hu 《Chinese Journal of Polymer Science》 SCIE EI CAS CSCD 2022年第4期421-430,共10页
Immiscible polymer blends are an important family of polymer materials.The interfacial thickness between different phases is a very important parameter that dictates,to a great extent,the morphology and properties of ... Immiscible polymer blends are an important family of polymer materials.The interfacial thickness between different phases is a very important parameter that dictates,to a great extent,the morphology and properties of such a blend.This work explores and optimizes an up-to-date atomic force microscopy(AFM)of type NanoIR2^(TM) system in order to quantitatively measure the interfacial thickness of immiscible polymer blends.This system is equipped with two nano-probes capable of detecting the response of a material to an infrared pulse called AFM-infrared spectroscopy mode(AFM-IR)or conducting resonance called AFM-Lorentz Contact Resonance mode(AFM-LCR),respectively.Its potential for quantitatively measuring the interfacial thickness of immiscible polymer blends is evaluated using blends composed of polyamide 6(PA6)and polyolefin elastomer(POE)in the presence or absence of a POE containing maleic anhydride(POE-g-MAH)as a compatibilizer.Surface roughness affects adversely the signal intensity and consequently an accurate measurement of the interfacial thickness.Optimum sample surface preparation procedures are proposed. 展开更多
关键词 Polymer blends Interfacial thickness Atomic force microscopy Nano-probing Surface roughness
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Generating strongly basic sites on magnetic nano-stirring bars:Multifunctional integrated catalysts for transesterification reaction
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作者 Chen Gu tian-tian li +4 位作者 Peng Tan Song-Song Peng Yao Jiang Xiao-Qin liu lin-Bing Sun 《Science China Materials》 SCIE EI CAS CSCD 2022年第10期2721-2728,共8页
Mass transfer and catalyst recovery are two crucial issues in solid base catalysis,while the cumbersome operation steps and the associated time and energy penalties are still inevitable for conventional catalysts.Achi... Mass transfer and catalyst recovery are two crucial issues in solid base catalysis,while the cumbersome operation steps and the associated time and energy penalties are still inevitable for conventional catalysts.Achieving the technical upgrades through catalyst design is desirable but challenging because of the difficulty in satisfying diverse demands of different steps.In this work,a magnetically responsive solid base catalyst with the rod-like nanostructure was developed.The rod-like solid base catalysts are composed of Fe_(3)O_(4) cores,silica shells and calcium oxide active sites.The functions of magnetic recovery and stirring were integrated into the catalyst,which applies in both the general catalytic processes and microchannel reactors given their nanoscales.When applied to the synthesis of dimethyl carbonate by onestep transesterification of methanol and ethylene carbonate,an apparent enhancement on turnover frequency value(33.1 h^(−1))was observed for nano-stirring compared with that tested without stirring(12.1 h^(−1))within 30 min.The present catalysts may open up new avenues in the development of advanced solid base catalysts. 展开更多
关键词 magnetic responsiveness nano-stirring bars dimethyl carbonate solid base catalyst
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Clean air actions and health plans in China
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作者 Chen Chen Jian-Long Fang +2 位作者 Wan-Ying Shi tian-tian li Xiao-Ming Shi 《Chinese Medical Journal》 SCIE CAS CSCD 2020年第13期1609-1611,共3页
China has been experiencing some of the world's most serious air pollution,especially severe smog events swept China in January of 2013,leading to extensive interna-tional attention.Efforts to understand and mitig... China has been experiencing some of the world's most serious air pollution,especially severe smog events swept China in January of 2013,leading to extensive interna-tional attention.Efforts to understand and mitigate the impacts of ambient air pollution on public health have been taken to tackle this pollution in China.Clean air actions developed nationwide have aggressively lowered fine particulate matter(PM2.5)pollution in recent years.1 National health plans and research projects on air pollution have been motivated and funded by the government.Rapidly growing epidemiological evidence has emerged to preliminarily uncover the effects of elevated levels of ambient air pollution on human health.However,China's pollution levels still exceed that of the World Health Organization(WHO)least-stringent target.Ambient air pollution still poses a serious threat to human health and welfare. 展开更多
关键词 POLLUTION CLEAN China.
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Bromination of N-phenyloxypropyl-N'-ethyl-4,4'-bipyridium in cucurbit[8]uril molecular reactor
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作者 tian-tian li Lan-Lan Wen +2 位作者 Hai-Long Ji Feng-Yu liu Shi-Guo Sun 《Chinese Chemical Letters》 SCIE CAS CSCD 2017年第2期463-466,共4页
CB[n](n= 6-8) is a family of synthetic macrocyclic host molecules composed of n glycoluril units,which can be employed as molecular reactor.N-Phenyloxypropyl-N'-ethyl-4,4'-bipyridium(1) was designed to form a ho... CB[n](n= 6-8) is a family of synthetic macrocyclic host molecules composed of n glycoluril units,which can be employed as molecular reactor.N-Phenyloxypropyl-N'-ethyl-4,4'-bipyridium(1) was designed to form a host-guest inclusion complex with CB[n](n = 6-8),subsequently,the bromination reaction of 1 and its corresponding inclusion complexes was investigated in this work.In the case of 1/CB[8],the folded including mode is quite helpful to acquire 1-bormination product completely through intramolecular charge transfer(ICT),and CB[8]can provide a safe bromination environment for 1. 展开更多
关键词 Cucurbituril Molecular reactor Intramolecular charge transfer(ICT) Bromination Inclusion
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