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聚酰亚胺纤维增强树脂基复合材料的研究 被引量:6
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作者 温友 孟祥胜 +2 位作者 范卫锋 阎敬灵 王震 《化工新型材料》 CAS CSCD 北大核心 2019年第1期57-61,共5页
以聚酰亚胺纤维为增强体,环氧树脂、双马来酰亚胺树脂、氰酸酯和聚酰亚胺树脂为基体,通过模压成型法制备了4种聚酰亚胺纤维增强的树脂基复合材料。研究了4种基体树脂低聚物的固化行为和流变性能,并表征了4种相应树脂基复合材料的热学、... 以聚酰亚胺纤维为增强体,环氧树脂、双马来酰亚胺树脂、氰酸酯和聚酰亚胺树脂为基体,通过模压成型法制备了4种聚酰亚胺纤维增强的树脂基复合材料。研究了4种基体树脂低聚物的固化行为和流变性能,并表征了4种相应树脂基复合材料的热学、力学、介电性能以及纤维与树脂之间的界面性能。结果表明:4种基体树脂低聚物最低黏度都低于15Pa·s,显示了良好的成型工艺性,环氧树脂基复合材料的力学性能最好,弯曲强度、弯曲模量和层间剪切强度分别达到716MPa、54.9GPa和56.5MPa;聚酰亚胺树脂基复合材料的耐热等级最高,玻璃化转变温度大于300℃;氰酸酯树脂基复合材料的介电性能最优,介电常数在低频段低于3.3。 展开更多
关键词 聚酰亚胺纤维 树脂基复合材料 热学性能 力学性能 介电性能
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基于电子鼻和顶空-气相色谱-离子迁移色谱法分析油炸细叶韭的风味特征 被引量:1
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作者 文佑 赵笑颖 +1 位作者 王成华 刘小玲 《食品科学》 EI CAS CSCD 北大核心 2022年第12期267-273,共7页
通过电子鼻和顶空-气相色谱-离子迁移色谱(headspace-gas chromatography-ion mobility chromatography,HS-GC-IMS)研究中国传统炒制方法加工的细叶韭的风味特征。通过主成分分析进行电子鼻检测发现,细叶韭的主要挥发性成分为氮氧化物... 通过电子鼻和顶空-气相色谱-离子迁移色谱(headspace-gas chromatography-ion mobility chromatography,HS-GC-IMS)研究中国传统炒制方法加工的细叶韭的风味特征。通过主成分分析进行电子鼻检测发现,细叶韭的主要挥发性成分为氮氧化物、萜烯、有机硫化物和含硫有机化合物,而油炸过程明显改变了细叶韭的风味结构,其中含硫化合物显著增加。HS-GC-IMS分析从油炸细叶韭和细叶韭之间共56种不同组分中鉴定出25种挥发性化合物,其中油炸细叶韭中的5种脂溶性化合物和2种水溶性化合物含量远大于细叶韭,证实了传统油炸加工基础上的风味变化。本实验结合电子鼻和HS-GC-IMS的互补优势对中国传统油炸方法处理的细叶韭进行风味表征,是一种有效、准确和灵敏的测定葱属植物风味方法。 展开更多
关键词 细叶韭 风味 电子鼻 油炸 顶空-气相色谱-离子迁移色谱
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Mixed methods evaluation of a randomized control pilot trial targeting sugar-sweetened beverage behaviors
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作者 Jamie Zoellner Emily Cook +3 位作者 Yvonnes Chen wen you Brenda Davy Paul Estabrooks 《Open Journal of Preventive Medicine》 2013年第1期51-57,共7页
This Excessive sugar-sweetened beverage (SSB) consumption and low health literacy skills have emerged as two public health concerns in the United States (US);however, there is limited research on how to effectively ad... This Excessive sugar-sweetened beverage (SSB) consumption and low health literacy skills have emerged as two public health concerns in the United States (US);however, there is limited research on how to effectively address these issues among adults. As guided by health literacy concepts and the Theory of Planned Behavior (TPB), this randomized controlled pilot trial applied the RE-AIM framework and a mixed methods approach to examine a sugar-sweetened beverage (SSB) intervention (SipSmartER), as compared to a matched-contact control intervention targeting physical activity (Move-More). Both 5-week interventions included two interactive group sessions and three support telephone calls. Executing a patient-centered developmental process, the primary aim of this paper was to evaluate patient feedback on intervention content and structure. The secondary aim was to understand the potential reach (i.e., proportion enrolled, representativeness) and effectiveness (i.e. health behaviors, theorized mediating variables, quality of life) of SipS- martER. Twenty-five participants were randomized to SipSmartER (n = 14) or MoveMore (n = 11). Participants’ intervention feedback was positive, ranging from 4.2 - 5.0 on a 5-point scale. Qualitative assessments reavealed several opportuneties to improve clarity of learning materials, enhance instructions and communication, and refine research protocols. Although SSB consumption decreased more among the SipS-martER participants (?256.9 ± 622.6 kcals), there were no significant group differences when compared to control participants (?199.7 ± 404.6 kcals). Across both groups, there were significant improvements for SSB attitudes, SSB behavioral intentions, and two media literacy constructs. The value of using a patient-centered approach in the developmental phases of this intervention was apparent, and pilot findings suggest decreased SSB may be achieved through targeted health literacy and TPB strategies. Future efforts are needed to examine the potential public health impact of a large-scale trial to address health literacy and reduce SSB. 展开更多
关键词 Beverages HEALTH LITERACY HEALTH Education Public HEALTH HEALTH Behavior PILOT Projects
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The Implementation of Waste Sawdust in Concrete
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作者 Yong Cheng wen you +2 位作者 Chaoyong Zhang Huanhuan Li Jian Hu 《Engineering(科研)》 2013年第12期943-947,共5页
Nowadays, sawdust has been widely regarded as a sand replacement material to produce sawdust concrete. This thesis uses orthogonal test to analyze the mechanical and heat preservation as well as heat insulation proper... Nowadays, sawdust has been widely regarded as a sand replacement material to produce sawdust concrete. This thesis uses orthogonal test to analyze the mechanical and heat preservation as well as heat insulation property with the sawdust replacement ratio of 0%, 3%, 5%, 7%, 10%, respectively, to get an optimal sawdust replacement ratio. Besides, it also discusses the deficiencies of this research. 展开更多
关键词 WASTE SAWDUST CONCRETE Mechanical PROPERTY Optimal SAWDUST REPLACEMENT RATIO
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Chemoprevention of colorectal cancer in general population and high-risk population: a systematic review and network meta-analysis
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作者 Ye Ma wen you +5 位作者 Yang Cao Xuxia He Jing Wang Yuelun Zhang Ji Li Jingnan Li 《Chinese Medical Journal》 SCIE CAS CSCD 2023年第7期788-798,共11页
Background:Many nutritional supplements and pharmacological agents have been reported to show preventive effects on colorectal adenoma and colorectal cancer(CRC).We performed a network meta-analysis to summarize such ... Background:Many nutritional supplements and pharmacological agents have been reported to show preventive effects on colorectal adenoma and colorectal cancer(CRC).We performed a network meta-analysis to summarize such evidence and assess the efficacy and safety of these agents.Methods:We searched PubMed,Embase,and the Cochrane Library for studies published in English until October 31,2021 that fit our inclusion criteria.We performed a systematic review and network meta-analysis to assess the comparative efficacy and safety of candidate agents(low-dose aspirin[Asp],high-dose Asp,cyclooxygenase-2 inhibitors[coxibs],calcium,vitamin D,folic acid,ursodeoxycholic acid[UDCA],estrogen,and progesterone,alone or in combination)for preventing colorectal adenoma and CRC.Cochrane risk-of-bias assessment tool was employed to evaluate the quality of each included study.Results:Thirty-two randomized controlled trials(278,694 participants)comparing 13 different interventions were included.Coxibs significantly reduced the risk of colorectal adenoma(risk ratio[RR]:0.59,95%confidence interval[CI]:0.44–0.79,six trials involving 5486 participants),advanced adenoma(RR:0.63,95%CI:0.43–0.92,four trials involving 4723 participants),and metachronous adenoma(RR:0.58,95%CI:0.43–0.79,five trials involving 5258 participants)compared with placebo.Coxibs also significantly increased the risk of severe adverse events(RR:1.29,95%CI:1.13–1.47,six trials involving 7109 participants).Other interventions,including Asp,folic acid,UDCA,vitamin D,and calcium,did not reduce the risk of colorectal adenoma in the general and high-risk populations compared with placebo.Conclusions:Considering the balance between benefits and harms,regular use of coxibs for prevention of colorectal adenoma was not supported by the current evidence.Benefit of low-dose Asp for chemoprevention of colorectal adenoma still requires further evidence. 展开更多
关键词 CHEMOPREVENTION Colorectal adenoma Colorectal cancer Cyclooxygenase-2 inhibitors Low-dose aspirin
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具有可调电子结构的无定型羟基硫化钴纳米片用于高性能电化学储能
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作者 项坤 王学万 +3 位作者 游雯 彭智昆 骆静利 符显珠 《Science China Materials》 SCIE EI CSCD 2020年第11期2303-2313,共11页
赝电容超级电容器具有高功率密度、超长寿命以及可靠的安全性,使其在能源转化和存储中扮演着重要角色.但是,设计具有高容量、优异倍率性能以及出色的机械稳定性的电极材料依旧是一个挑战.本工作中,我们采用室温部分硫化策略来调节氢氧... 赝电容超级电容器具有高功率密度、超长寿命以及可靠的安全性,使其在能源转化和存储中扮演着重要角色.但是,设计具有高容量、优异倍率性能以及出色的机械稳定性的电极材料依旧是一个挑战.本工作中,我们采用室温部分硫化策略来调节氢氧化钴纳米片的电子结构和晶态.得到的羟基硫化钴具有无定形结构,同时还有丰富的低价钴离子.三电极体系下,该电极在电流密度为1 A g^-1时的比电容达2110 F g^-1,当电流密度增大至10 A g^-1时容量仍有92.1%的保留,容量和倍率性能都远高于氢氧化钴前驱体(916 F g^-1@1 A g^-1,10 A g^-1的比电容保留率为80%).此外,利用该电极与商业活性炭组成的不对称电容器具有44.9 W h kg^-1的高能量密度以及优异的稳定性(8000次循环后仅衰减4%). 展开更多
关键词 电化学储能 比电容 倍率性能 超长寿命 纳米片 硫化钴 机械稳定性 无定形结构
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