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改装输血器在硅油取出术中的应用
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作者 肖瑶 马晓薇 《中华现代护理杂志》 2019年第9期1163-1166,共4页
目的探讨改装输血器在23G微创玻璃体切除系统硅油取出术中的应用效果。方法采用便利抽样法,选取眼科2017年1—12月收治的157例硅油眼患者共157只眼。采用改装输血器连接23G微创玻璃体切除系统抽吸取出硅油。评价患者术后眼压变化情况。... 目的探讨改装输血器在23G微创玻璃体切除系统硅油取出术中的应用效果。方法采用便利抽样法,选取眼科2017年1—12月收治的157例硅油眼患者共157只眼。采用改装输血器连接23G微创玻璃体切除系统抽吸取出硅油。评价患者术后眼压变化情况。结果157例患者均顺利完成了硅油取出术,手术效果满意。术后1周眼压均恢复正常。结论将用输血器改装的取油管应用于23G微创玻璃体切除硅油取出手术中是完全可行的。 展开更多
关键词 玻璃体切除术 改装 23G微创玻璃体切除系统 硅油取出术
Effects of fractional-order PI controller on delay margin in single-area delayed load frequency control systems 预览
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作者 Vedat CELIK Mahmut Temel OZDEMIR Kwang Y.LEE 《现代电力系统与清洁能源学报(英文)》 CSCD 2019年第2期380-389,共10页
This study aims to determine the improvement effect on the delay margin if fractional-order proportional integral(PI) controller is used in the control of a singlearea delayed load frequency control(LFC) system. The d... This study aims to determine the improvement effect on the delay margin if fractional-order proportional integral(PI) controller is used in the control of a singlearea delayed load frequency control(LFC) system. The delay margin of the system with fractional-order PI control has been obtained for various fractional integral orders and the effect of them has been shown on the delay margin as a third controller parameter. Furthermore,the stability of the system that is either under or over the delay margin is examined by generalized modified Mikhailov criterion.The stability results obtained have been confirmed numerically in time domain. It is demonstrated that the proposed controller for delayed LFC system provides more flexibility on delay margin according to integer-order PI controller. 展开更多
关键词 DELAY dependent stability DELAY MARGIN FRACTIONAL-ORDER proportional integral(PI) Generalized modified Mikhailov CRITERION Load frequency control with DELAY
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改性生物质活性炭对甲醛气体吸附性能 预览
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作者 刘秀玉 张浩 《非金属矿》 CAS CSCD 北大核心 2019年第4期82-85,共4页
以山核桃壳作为碳质材料制备生物质活性炭,分别利用磷酸与氨水对生物质活性炭进行改性处理,获得改性生物质活性炭。研究了酸改性生物质活性炭和碱改性生物质活性炭对甲醛吸附性能的影响,对改性生物质活性炭进行了表征分析。结果表明:利... 以山核桃壳作为碳质材料制备生物质活性炭,分别利用磷酸与氨水对生物质活性炭进行改性处理,获得改性生物质活性炭。研究了酸改性生物质活性炭和碱改性生物质活性炭对甲醛吸附性能的影响,对改性生物质活性炭进行了表征分析。结果表明:利用磷酸对生物质活性炭进行改性,其甲醛吸附性能大幅提高,当磷酸与山核桃壳超微粉的质量比为1.5∶1时,酸改性生物质活性炭对甲醛的吸附性能最优,即甲醛吸附效率为44.5%。酸改性生物质活性炭的层状结构明显,其颗粒之间形成了大量结构清晰且明显的不同形状孔隙。酸改性生物质活性炭有利于提高表面极性,改善粒径分布,增加比表面积。 展开更多
关键词 生物质活性炭 改性 吸附 甲醛气体 酸碱
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纤维改性土壤的研究现状与进展 预览
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作者 邓可 王恺 +3 位作者 刘冶球 杨毅 黄梅欢 肖晓华 《广东化工》 CAS 2019年第13期112-113,共2页
纤维改性土壤是一种新型土工复合材料,利用土壤对纤维的握裹力和纤维网对土壤的空间约束力来提高土壤的抗变形能力和稳定性,改善土壤的抗冲击性能和韧性,在基础设施建设领域具有巨大的市场价值和广阔的应用前景。综述了纤维改性土壤概况... 纤维改性土壤是一种新型土工复合材料,利用土壤对纤维的握裹力和纤维网对土壤的空间约束力来提高土壤的抗变形能力和稳定性,改善土壤的抗冲击性能和韧性,在基础设施建设领域具有巨大的市场价值和广阔的应用前景。综述了纤维改性土壤概况,分别介绍了无机纤维、人造合成纤维、植物纤维改性土壤的研究现状,展望了纤维改性土壤的发展前景。 展开更多
关键词 纤维 土壤 改性
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Performance of risk stratification systems for gastrointestinal stromal tumors: A multicenter study 预览
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作者 Tao Chen Liang-Ying Ye +11 位作者 Xing-Yu Feng Hai-Bo Qiu Peng Zhang Yi-Xin Luo Li-Yi Yuan Xin-Hua Chen Yan-Feng Hu Hao Liu Yong Li Kai-Xiong Tao Jiang Yu Guo-Xin Li 《世界胃肠病学杂志:英文版》 SCIE CAS 2019年第10期1238-1247,共10页
BACKGROUND Gastrointestinal stromal tumors(GISTs) are the most common mesenchymal tumor type in the gastrointestinal system. Presently, various classification systems to prognosticate GISTs have been proposed.AIM To e... BACKGROUND Gastrointestinal stromal tumors(GISTs) are the most common mesenchymal tumor type in the gastrointestinal system. Presently, various classification systems to prognosticate GISTs have been proposed.AIM To evaluate the application value of four different risk stratification systems for GISTs.METHODS Patients who were diagnosed with GISTs and underwent surgical resection at four hospitals from 1998 to 2015 were identified from a database. Risk of recurrence was stratified by the modified National Institute of Health(NIH)criteria, the Armed Forces Institute of Pathology(AFIP) criteria, the Memorial Sloan Kettering Cancer Center(MSKCC) prognostic nomogram, and the contour maps. Receiver operating characteristic(ROC) curves were established to compare the four abovementioned risk stratification systems based on the area under the curve(AUC).RESULTS A total of 1303 patients were included in the study. The mean age of the patients was 55.77 ± 13.70 yr;52.3% of the patients were male. The mean follow-up period was 64.91 ± 35.79 mo. Approximately 67.0% the tumors were located in the stomach, and 59.5% were smaller than 5 cm;67.3% of the patients had a mitotic count ≤ 5/50 high-power fields(HPFs). Thirty-four tumors ruptured before and during surgery. Univariate analysis demonstrated that tumor size > 5 cm(P <0.05), mitotic count > 5/50 HPFs(P < 0.05), non-gastric location(P < 0.05), and tumor rupture(P < 0.05) were significantly associated with increased recurrence rates. According to the ROC curve, the AFIP criteria showed the largest AUC(0.754).CONCLUSION According to our data, the AFIP criteria were associated with a larger AUC than the NIH modified criteria, the MSKCC nomogram, and the contour maps, which might indicate that the AFIP criteria have better accuracy to support therapeutic decision-making for patients with GISTs. 展开更多
关键词 GASTROINTESTINAL stromal TUMORS Risk STRATIFICATION Prognosis Modified National Institute of Health CRITERIA Armed Forces Institute of Pathology CRITERIA MEMORIAL Sloan Kettering Cancer Center prognostic NOMOGRAM Contour maps GASTROINTESTINAL TUMORS
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有机硅改性聚醚OF-125原油破乳剂的合成及其性能研究 预览
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作者 王众 李丹阳 +5 位作者 刘兴涛 杨昌鑫 马玲 任亚君 吴伟龙 刘平 《石河子大学学报:自然科学版》 CAS 北大核心 2019年第3期273-280,共8页
针对克拉玛依油田现有原油破乳剂对稠油乳状液破乳效果不理想的现状,本文以多胺类嵌段聚醚为基础物,与丙烯酸酯化后和含氢硅油进行硅氢加成的方法进行改性。实验结果表明:采用一锅法,在聚醚∶烯酸∶氢硅油为10∶0.8∶1.1(质量比),对甲... 针对克拉玛依油田现有原油破乳剂对稠油乳状液破乳效果不理想的现状,本文以多胺类嵌段聚醚为基础物,与丙烯酸酯化后和含氢硅油进行硅氢加成的方法进行改性。实验结果表明:采用一锅法,在聚醚∶烯酸∶氢硅油为10∶0.8∶1.1(质量比),对甲苯磺酸0.08%,氯铂酸40μg/g,反应温度80℃,反应时间8 h的最佳条件下合成了有机硅改性的OF系列破乳剂,并对其进行了表征;在反应温度75℃时,改性后的OF125原油破乳剂在有效加药量减少40%的条件下,破乳效果优于现用的破乳剂。 展开更多
关键词 聚醚 丙烯酸 含氢硅油 改性 破乳脱水
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Boundary segmentation based on modified random walks for vascular Doppler optical coherence tomography images
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作者 黄勇 吴传超 +6 位作者 夏绍燕 刘路 陈山林 童德迪 艾丹妮 杨健 王涌天 《中国光学快报:英文版》 SCIE EI CAS CSCD 2019年第5期15-20,共6页
Vascular Doppler optical coherence tomography (DOCT) images with weak boundaries are usually difficult for most algorithms to segment. We propose a modified random walk (MRW) algorithm with a novel regularization for ... Vascular Doppler optical coherence tomography (DOCT) images with weak boundaries are usually difficult for most algorithms to segment. We propose a modified random walk (MRW) algorithm with a novel regularization for the segmentation of DOCT vessel images. Based on MRW, we perform automatic boundary detection of the vascular wall from intensity images and boundary extraction of the blood flowing region from Doppler phase images. Dice, sensitivity, and specificity coefficients were adopted to verify the segmentation performance. The experimental study on DOCT images of the mouse femoral artery showed the effectiveness of our proposed method, yielding three-dimensional visualization and quantitative evaluation of the vessel. 展开更多
关键词 Boundary SEGMENTATION based DOPPLER optical COHERENCE tomography(DOCT) MODIFIED random walk(MRW)
改性冬青叶对水中Cu(Ⅱ)和Cr(Ⅵ)的吸附性能研究 预览
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作者 曲艳萍 李红翠 +2 位作者 高晓娟 胡永花 刘凤红 《齐鲁工业大学学报:自然科学版》 2019年第4期32-38,共7页
采用冬青叶作为原料,并对其进行H2SO4-甲醛改性,制得酸改性冬青叶吸附剂,进而研究改性冬青叶投加量、振荡时间、反应pH、温度、溶液的初始浓度对改性冬青叶吸附性能的影响;进行吸附等温拟合和动力学分析,初步探讨了改性冬青叶对Cu(Ⅱ)和... 采用冬青叶作为原料,并对其进行H2SO4-甲醛改性,制得酸改性冬青叶吸附剂,进而研究改性冬青叶投加量、振荡时间、反应pH、温度、溶液的初始浓度对改性冬青叶吸附性能的影响;进行吸附等温拟合和动力学分析,初步探讨了改性冬青叶对Cu(Ⅱ)和Cr(Ⅵ)的吸附机理。实验结果表明:当改性冬青叶投加量为0. 3 g、振荡时间为20 min、反应pH为4、温度为25℃、溶液的初始浓度为100 mg/L的条件下,对Cr(Ⅵ)的去除率最高约为60%;当改性冬青叶投加量为0. 2 g、振荡时间为40 min、反应pH为5、温度为25℃、溶液初始浓度为100 mg/L的条件下,对Cu(Ⅱ)的去除率最高约为80%;两种金属离子的吸附过程均符合动力学二级反应方程和Freundlich等温方程。 展开更多
关键词 改性 冬青叶 吸附 Cu(Ⅱ) Cr(Ⅵ)
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聚氨酯胶粘剂的研究进展、合成、改性与应用 预览
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作者 李国遵 高之香 +3 位作者 李士学 李建武 陈雨 赵苗 《粘接》 CAS 2019年第5期177-180,共4页
通过查阅国内外相关文献资料,简要阐述了聚氨酯胶粘剂的性能、结构、合成、改性及应用等相关内容,综述了聚氨酯胶粘剂目前国内外的研究现状及研究进展,并对聚氨酯胶粘剂的发展做了展望。
关键词 聚氨酯胶粘剂 合成 改性 应用 研究进展
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Effect of Modified Vermiculite on the Interface of a Capric Acid-expanded Vermiculite Composite Phase Change Material with Phase Transition Kinetics
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作者 ZHANG Hongguang ZHU Jiaoqun +2 位作者 CHENG Xiaomin ZHOU Weibing LIU Fengli 《武汉理工大学学报:材料科学英文版》 SCIE EI CAS 2019年第2期345-352,共8页
A new type of capric acid(CA)-acid expanded vermiculite(AEV) composite phase change material(PCM) with improved adsorption ability and interface adhesive strength was developed. Through the analysis of non-isothermal ... A new type of capric acid(CA)-acid expanded vermiculite(AEV) composite phase change material(PCM) with improved adsorption ability and interface adhesive strength was developed. Through the analysis of non-isothermal phase transition kinetics, modified vermiculite was observed to change and affect the phase transformation mechanism of the composite. AEV was treated with hydrochloric acid to improve the specific surface area and micro-pore structure. The surface area measured by BET increased from 81.94 m2/g for expanded vermiculite(EV) to 544.13 m2/g for AEV. CA-EV and CA-AEV composite PCMs were prepared by direct impregnation. The non-isothermal phase transition isotherms of CA-EV and CA-AEV were recorded by DSC at different heating rates(1, 5, 10, 15, and 20 ℃/min), which indicated that the phase transition rate increased with the heating rate and the phase transition process changed. Kinetics parameters were analyzed by a double extrapolation method. The activation energy(E) under the original state(Eα→0) of CA-AEV and CA-EV was 1 117 kJ/mol and 937 kJ/mol, respectively, and 1 205 kJ/mol and 1 016 kJ/mol under the thermal equilibrium state(Eβ→0). The most probabilistic mechanism function of CA-AEV satisfied G(α)=α2/3, which followed the Mample special rule, and the function of CA-EV satisfied G(α)=[(1+α)1/3-1]2, which followed the anti-Jander function. 展开更多
关键词 modified VERMICULITE PHASE CHANGE material PHASE TRANSITION KINETICS thermal storage
Non-parametric reconstruction of growth index via Gaussian processes
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作者 Zhao-Yu Yin Hao Wei 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第9期110-119,共10页
The accelerated cosmic expansion could be due to dark energy within general relativity(GR), or modified gravity. Differentiating between them using both the expansion history and growth history has attracted considera... The accelerated cosmic expansion could be due to dark energy within general relativity(GR), or modified gravity. Differentiating between them using both the expansion history and growth history has attracted considerable attention. In the literature, the growth index γ has been found useful to distinguish these two scenarios. This work aims to consider the non-parametric reconstruction of the growth index γ as a function of redshift z from the latest observational data as of July 2018 via Gaussian processes. We found that f(R) theories and dark energy models within GR(especially ΛCDM) are inconsistent with the results in the moderate redshift range far beyond 3σ confidence level. A modified gravity scenario different from f(R) theories is favored. However, these results can also be due to other non-trivial possibilities in which dark energy models within GR(especially ΛCDM) and f(R) theories may still survive. In all cases, our results suggest that new physics is required. 展开更多
关键词 COSMOLOGY DARK energy modified GRAVITY growth index GAUSSIAN processes
改性生物质电厂灰钝化修复南方镉污染土壤及其长效性研究 预览 被引量:1
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作者 宋乐 韩占涛 +4 位作者 张威 马丽莎 王磊 李雄光 王喜龙 《中国环境科学》 EI CAS CSCD 北大核心 2019年第1期226-234,共9页
选取我国南方生物质发电厂的灰渣为原料,经物理和化学改性制成重金属钝化剂,针对我国南方重金属Cd污染的土壤开展钝化修复研究.底灰中Cd等重金属含量明显低于其对应的飞灰,这是选择底灰作原料的重要原因.用其制备的BFA型钝化剂在水中对C... 选取我国南方生物质发电厂的灰渣为原料,经物理和化学改性制成重金属钝化剂,针对我国南方重金属Cd污染的土壤开展钝化修复研究.底灰中Cd等重金属含量明显低于其对应的飞灰,这是选择底灰作原料的重要原因.用其制备的BFA型钝化剂在水中对Cd的吸附量可达16mg/g以上.室内盆栽试验中,添加土壤干重1%的钝化剂,第一季稻米Cd含量降低80%以上,从超标2.8倍降至达标;第二季小麦籽粒Cd降低70%,从超标0.9倍降至达标.在我国南方Cd重度污染的农田中开展的原位修复试验表明,添加1%的钝化剂,稻米和小麦籽粒中Cd降低70%~90%,其中稻米Cd持续降低,2017年降低率相较2016年继续提升10%~20%,最终从超标20倍降至达标;Ni降低60%以上,且保留有益的Cu、Zn元素不受明显影响;此BFA型钝化剂还能促进作物生长,第一季稻米产量提高40%~60%,第二季仍有一定的增长效果.综合安全性考虑,我国南方生物质电厂的灰渣重金属含量很低,经过改性加工可制成安全高效的重金属钝化剂.可为钝化修复我国南方重金属污染农田提供一种经济有效的方法,也为现阶段难以处置的灰渣提供一个重要的利用途径. 展开更多
关键词 生物质电厂灰 钝化剂 改性 中国南方
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Effects of precursor moisture and inert N2 atmosphere calcinations on structure and properties of alumina modified CeZrLaNd mixed oxides
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作者 Meisheng Cui Zhizhe Zhai +3 位作者 Hao Wang Yongke Hou Yongqi Zhang Xiaowei Huang 《中国稀土学报:英文版》 SCIE EI CAS CSCD 2019年第6期609-616,共8页
CeO2-ZrO2 mixed oxides are widely used in the three-way catalysts due to their unique reversible oxygen storage and release capacity. Large surface area, high oxygen storage capacity and good thermal stability of ceri... CeO2-ZrO2 mixed oxides are widely used in the three-way catalysts due to their unique reversible oxygen storage and release capacity. Large surface area, high oxygen storage capacity and good thermal stability of cerium zirconium mixed oxides are the key properties for the automotive catalysts so as to meet the strict emission regulations. In this work, alumina modified CeZrLaNd mixed oxides were prepared by a co-precipitation method. The effects of moisture in precursor and inert N2 atmosphere during calcinations on the structure and properties were investigated by Brunauer-Emmett-Teller(BET) surface area measurements, X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), hydrogen temperature-programmed reduction(H2-TPR), oxygen storage capacity(OSC), Raman spectroscopy, and X-ray photoelectron spectroscopy(XPS). The results show that the moisture in precursor during calcinations increases the crystal grain size of the cerium zirconium mixed oxides, improving the thermal stability. And the aged surface area of sample after being calcined at1000 ℃ for 4 h reaches 68.8 m2/g(5.7% increase compared with the common sample). The inert N2 atmosphere endows a great pore-enlarging effect, which leads to high fresh surface area of 148.9 m2/g(13.5% increase compared with the common sample) and big pore volume of 0.5705 mL/g. The redox and oxygen storage capacity are also improved by inert N2 atmosphere with high OSC value of 241.06μmolO2/g(41.3% increase compared with the common calcination), due to the abundant formation of the crystal defects and oxygen vacancies. 展开更多
关键词 PRECURSOR MOISTURE Inert N2 ATMOSPHERE CALCINATIONS ALUMINA modified CeZrLaNd mixed oxides Rare earths
桑白皮汤加减治疗慢性阻塞性肺疾病急性加重期的Meta分析和试验序贯分析
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作者 郑文江 彭紫荆 +4 位作者 严倩 张超源 刘碧娥 洪榆 刘小虹 《中国中药杂志》 CAS CSCD 北大核心 2019年第17期3806-3815,共10页
电子检索中国学术期刊全文数据库(CNKI)、PubMed等7大中英文数据库,检索时间限定为自建库至2018年12月5日,检出所有桑白皮汤加减治疗慢性阻塞性肺疾病急性加重期(AECOPD)患者(试验组)的临床随机对照试验(RCTs),由2名研究员各自独立严格... 电子检索中国学术期刊全文数据库(CNKI)、PubMed等7大中英文数据库,检索时间限定为自建库至2018年12月5日,检出所有桑白皮汤加减治疗慢性阻塞性肺疾病急性加重期(AECOPD)患者(试验组)的临床随机对照试验(RCTs),由2名研究员各自独立严格按照纳入和排除标准进行纳入研究的质量评价和资料提取,用Stata/SE 14. 0进行Meta分析、TSA0. 9. 5. 10 Beta软件进行试验序贯分析,系统评价桑白皮汤加减治疗AECOPD患者的临床疗效和安全性。共纳入25个RCT包括1 784例患者。Meta分析:与对照组相比,试验组在改善AECOPD患者的临床症状方面优于对照组(RR=1. 18,95%CI[1. 13,1. 22],P=0);在肺功能方面,改善第1秒用力呼气量(FEV1)(WMD=0. 44,95%CI[0. 01,0. 87],P=0. 046)和用力肺活量(FVC)(WMD=0. 14,95%CI[0. 07,0. 22],P=0),但对FEV1占预计值的百分比(FEV1%)(P=0. 067)、第1秒用力呼吸容积占用力肺活量百分比(FEV1/FVC)(P=0. 238)则无统计学差异;提高患者动脉血氧分压(PaO2)(SMD=0. 85,95%CI[0. 41,1. 30],P=0)、降低二氧化碳分压(PaCO2)(SMD=-0. 94,95%CI[-1. 70,-0. 18],P=0. 016);在感染指标方面,改善白细胞计数(WBC)(WMD=-0. 94,95%CI[-1. 17,-0. 70],P=0);同时,试验组的不良反应较少且无严重不良反应事件。试验序贯分析(TSA)显示临床有效率累积纳入的研究穿过了传统界值和TSA界值,表明试验组的临床疗效得到进一步肯定。研究表明,在常规西医治疗基础上联合桑白皮汤加减治疗AECOPD患者,可提高临床疗效、提高PaO2、降低PaCO2、安全性较好,在改善肺功能方面疗效欠佳。该研究受纳入研究质量的限制,所得结论尚需要更多高质量RCT进一步验证。 展开更多
关键词 桑白皮汤 加减 慢性阻塞性肺疾病 急性加重期 META分析 试验序贯分析
水性聚氨酯阻燃胶黏剂的制备及性能研究 预览
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作者 黄传峰 刘青青 +5 位作者 闵钰茹 张丹丹 崔玮 夏其英 梁士明 马登学 《山东化工》 CAS 2019年第5期34-36,共3页
以羟基封端的聚二甲基硅氧烷为改性试剂、己内酰胺为封端剂、羧酸基多元醇做亲水扩链剂,采用阴离子自乳化的方法制备一种聚二甲基硅氧烷改性的环境友好型水性聚氨酯阻燃胶黏剂。通过傅里叶变换红外光谱仪(FT-IR)、万能试验机,极限氧指... 以羟基封端的聚二甲基硅氧烷为改性试剂、己内酰胺为封端剂、羧酸基多元醇做亲水扩链剂,采用阴离子自乳化的方法制备一种聚二甲基硅氧烷改性的环境友好型水性聚氨酯阻燃胶黏剂。通过傅里叶变换红外光谱仪(FT-IR)、万能试验机,极限氧指数测试仪等实验仪器对水性聚氨酯阻燃胶黏剂进行了阻燃性能和力学性能表征。研究结果表明,羟基封端的聚硅氧烷接入分子链结构中,合成的聚氨酯具有良好的阻燃效果,并且得到难燃的胶黏材料,表现出良好的阻燃与力学性能。 展开更多
关键词 水性聚氨酯 阻燃 改性 有机硅 胶黏剂
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缓凝剂对磷石膏基建筑石膏性能的影响 预览
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作者 郑光亚 夏举佩 +2 位作者 韩跃伟 陈正杰 刘成龙 《非金属矿》 CAS CSCD 北大核心 2019年第5期79-81,共3页
以云南安宁某磷肥厂的磷石膏为原料,制备磷石膏基建筑石膏。采用3种不同类型的缓凝剂,即蛋白质类缓凝剂中的动物蛋白SH缓凝剂、碱性磷酸盐缓凝剂中的多聚磷酸钠PC缓凝剂及有机酸类缓凝剂中的柠檬酸钾CQ缓凝剂,考察不同缓凝剂的掺量对磷... 以云南安宁某磷肥厂的磷石膏为原料,制备磷石膏基建筑石膏。采用3种不同类型的缓凝剂,即蛋白质类缓凝剂中的动物蛋白SH缓凝剂、碱性磷酸盐缓凝剂中的多聚磷酸钠PC缓凝剂及有机酸类缓凝剂中的柠檬酸钾CQ缓凝剂,考察不同缓凝剂的掺量对磷石膏基建筑石膏的凝结时间、抗折抗压强度的影响。结果表明,动物蛋白缓凝剂缓凝效果最好,并且对建筑石膏的强度影响较小。 展开更多
关键词 磷石膏 建筑石膏 缓凝剂 改性
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改性香蕉皮粉末和香蕉皮活性炭吸附水中甲氰菊酯的对比研究 预览
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作者 孟琪 吴彦 +4 位作者 李灵 罗冉嘉 程绪红 樊一桥 平巍 《三峡生态环境监测》 2019年第1期68-75,共8页
为探讨农业固体废弃物的有效资源化,以香蕉皮为原料,分别制备改性香蕉皮粉末(modified banana peel powder,MBP)和香蕉皮活性炭(banana peel activated carbon,BAC)用以吸附水中的甲氰菊酯。通过静态吸附实验对比两种材料对水中甲氰菊... 为探讨农业固体废弃物的有效资源化,以香蕉皮为原料,分别制备改性香蕉皮粉末(modified banana peel powder,MBP)和香蕉皮活性炭(banana peel activated carbon,BAC)用以吸附水中的甲氰菊酯。通过静态吸附实验对比两种材料对水中甲氰菊酯的吸附效果。扫描电镜、BET法测定比表面积及孔径分析表征结果表明,BAC比MBP有更大的比表面和更发达的孔道结构;傅里叶变换红外光谱表征结果显示,MBP比BAC具有更多的表面官能团结构。静态吸附实验结果显示:在pH为4~9范围内,MBP对甲氰菊酯的吸附容量和吸附速率均低于BAC。两种材料吸咐甲氰菊酯的最佳pH为7,在此条件下,MBP和BAC的饱和吸附量分别为58.215μg/g和91.005μg/g;等温拟合结果显示:两种材料吸附水中甲氰菊酯的吸附均倾向于Langmuir等温模型,说明其吸附倾向于化学吸附;Freundlich等温拟合结果显示:香蕉皮活性炭具有更低的1/n值,说明其吸附甲氰菊酯更容易发生;吸附动力学模型拟合结果显示:改性香蕉皮粉末及活性炭对甲氰菊酯的吸附更倾向于准二阶动力学模型。研究结果表明,BAC吸附水中甲氰菊酯的效果优于MBP,同时,MBP作为一种低成本生物吸附材料,对水中的甲氰菊酯也具备一定的吸附能力,且属于容易发生的吸附。 展开更多
关键词 改性 香蕉皮 活性炭 吸附 甲氰菊酯
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PEG改性明胶的制备和性能测试 预览
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作者 张云凤 常西亮 王灿 《化工技术与开发》 CAS 2019年第10期10-13,共4页
采用流延干燥成膜法制备不同平均分子量的PEG,并与明胶复合成膜,探究相对分子量不同的PEG对改性明胶复合膜的理化性质的影响。结果显示,添加不同分子量的PEG,能够不同程度地降低改性明胶膜的吸水性和透水气性;SEM和TG分析发现,PEG的加... 采用流延干燥成膜法制备不同平均分子量的PEG,并与明胶复合成膜,探究相对分子量不同的PEG对改性明胶复合膜的理化性质的影响。结果显示,添加不同分子量的PEG,能够不同程度地降低改性明胶膜的吸水性和透水气性;SEM和TG分析发现,PEG的加入对改性明胶膜的表面微观结构、热稳定性及降解速率的影响不大。PEG中羟基与明胶的氢键作用,使改性明胶红外光谱中的吸收峰向低波数偏移。 展开更多
关键词 PEG 明胶 改性
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Generation of pigs with a Belgian Blue mutation in MSTN using CRISPR/Cpf1-assisted ssODN-mediated homologous recombination 预览
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作者 ZOU Yun-long LI Zhi-yuan +4 位作者 ZOU Yun-jing HAO Hai-yang HU Jia-xiang LI Ning LI Qiu-yan 《农业科学学报:英文版》 SCIE CAS CSCD 2019年第6期1329-1336,共8页
CRISPR/Cpf1 has emerged recently as an effective tool for genome editing in many organisms,but its use in pigs to generate precise genetic modifications has seldom been described.Myostatin(MSTN)is a well-characterized... CRISPR/Cpf1 has emerged recently as an effective tool for genome editing in many organisms,but its use in pigs to generate precise genetic modifications has seldom been described.Myostatin(MSTN)is a well-characterized negative regulator of muscle development,and natural mutations in this gene cause a double-muscled phenotype in many species.However,to the best of our knowledge,no naturally occurring mutation in MSTN has been found in pigs.In addition,no living pig models with sophisticated modifications orthologous to natural mutations in MSTN have yet been reported.In this study,we exploited the CRISPR/Cpf1 system to introduce a predefined modification orthologous to the natural MSTN mutation found in Belgian Blue cattle(thus known as the Belgian Blue mutation).Our research demonstrated that the cutting efficiency of CRISPR/Cpf1 was 12.3%in mixed porcine fetal fibroblasts in drug free medium,and 41.7%in clonal colonies obtained using G418 selection.Then,the Cpf1-sgRNA vector,ssODN template,and a self-excision cassette were co-transfected into porcine fetal fibroblasts.After G418 selection,8 clonal colonies were examined and 5 with genetic modification were found.Of these 5,2 harbored the precise 11-bp deletion.Using 1 heterozygous clonal colony,2 cloned Duroc piglets were successfully generated,which was heterozygous for the Belgian Blue mutation.In summary,our results demonstrate that CRISPR/Cpf1 system can be used efficiently to generate double-stranded breaks,and also to mediate homologous recombination to introduce precise genomic modifications in pigs. 展开更多
关键词 MSTN CRISPR/Cpf1 Belgian BLUE MUTATION genetically modified PIGS single stranded OLIGODEOXYNUCLEOTIDE
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菱镁材料的改性及其应用
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作者 周会 《粉煤灰综合利用》 CAS 2019年第3期43-46,共4页
利用粉煤灰、硅酸钠等研制了双组分菱镁材料改性剂,用于菱镁材料的改性,大大提高了菱镁材料的耐水性、强度和抗返卤性能。并利用改性好的菱镁材料以及玻化微珠制备菱镁基无机保温材料,用于建筑物的保温,拓展了菱镁材料的应用领域。
关键词 氧化镁 氯化镁 粉煤灰 改性 菱镁基无机保温材料
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