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Search Results: 1 - 10 of 160530 matches for " 杨秀树 "
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基于模糊聚类分析的无功电压控制分区
,董征,唐宝,
中国电机工程学报 , 2006,
Abstract: 无功电压控制研究中的系统分区是一个非线性的大规模组合优化问题,使用常规方法常难以得到理想的结果。运用模糊聚类分析法将系统分区,并基于电压幅值对无功功率的灵敏度定义了电力系统各节点间的电气距离,对待分类对象的全体作适当的标定,运用传递闭包法求出动态分类,通过计算统计量F最后得出最优分类。该方法所占内存小,计算速度快。经IEEE39节点测试系统对该方法进行了验证,其结果表明:该方法有效、可行。
风电场风速和发电功率预测研究
,肖洋,
中国电机工程学报 , 2005,
Abstract:
Notch1过表达对K562细胞增殖及其周期的影响
,陈建斌,,李芳菲
第三军医大学学报 , 2011,
Abstract: 目的研究外源性Notch1过表达对慢性粒细胞白血病细胞株K562增殖和细胞周期的影响。方法用脂质体将携带Notch1胞内段(ICN1)的质粒转染入K562细胞,倒置相差显微镜观察转染前后K562细胞形态学变化,RT-PCR和Westernblot检测Notch1mRNA和蛋白的表达,MTT比色法检测细胞增殖,流式细胞仪检测细胞周期分布。结果与未转染组相比,ICN1转染组K562细胞数量减少,成团生长,直径和体积均变小;Notch1mRNA及其蛋白表达均比未转染组增强;ICN1转染组K562细胞增殖显著受抑(P<0.01),且随时间延长而明显(P<0.05);细胞周期检测表明G1期细胞增多(P<0.05),S期细胞显著减少(P<0.01)。结论Notch1胞内段过表达可能通过阻滞细胞于G1期而抑制K562细胞增殖。
肝素结构与功能的研究进展
高宁国,,,
中国生物工程杂志 , 1999,
Abstract: 肝素是一类结构异常复杂的糖胺聚糖,与此相对应的是其多种生物学功能。除了经典的抗凝血及其相关的抗血拴生成以外,肝素还具有抗平滑肌细胞增殖、抗炎症、抗肿瘤及抗病毒等,并且这些生物活性同抗凝活性无关,而同肝素的特异结构密切相关。本文综述了肝素的多种生物学功能、作用机制及结构与功能的关系。
长期施肥对塿土磷素状况的影响
学云, 孙本华, 古巧珍, 李生,
植物营养与肥料学报 , 2009, DOI: 10.11674/zwyf.2009.0415
Abstract: 利用塿土12年长期肥料定位试验,研究了不同施肥方式对耕层土壤全磷(TP)、有机磷(OP)与有效磷(Olsen-P)的影响。结果表明,施用化学磷肥提高了耕层土壤TP、Olsen-P含量,但并未提高OP含量;对照与磷钾处理的OP含量有降低趋势。当基于含氮量施有机肥时,土壤TP和Olsen-P含量大幅度提高,也提高了OP含量,但OP/TP比率在降低到一定程度后维持在一个较为稳定的水平;即使施用有机肥的处理,磷素也主要以无机形态累积。土壤Olsen-P与TP或两者的增加量都呈显著的线性相关,塿土TP每提高100mg/kg,Olsen-P增加量约为20.8mg/kg,且单位土壤全磷增加带来的Olsen-P增加有随施肥时间降低的趋势。在土壤Olsen-P含量达到一定水平时应考虑减少磷肥用量。基于有机肥中磷素含量来推荐有机肥施用或延长其施用的时间间隔,将有助于减少由于有机肥施用带来的磷素大量快速累积。
两种生物菌剂对安丘大姜姜瘟病的防效
郑春寒,庆峰,肖艳,,季?
北方园艺 , 2015, DOI: 10.11937/bfyy.201515031
Abstract: 以荧光假单胞菌和枯草芽孢杆菌为试材,以“绵姜”大姜为供试作物,采用生物防治的技术方法,研究了2种生物菌剂对姜瘟病的影响。结果表明2种生防菌剂对姜瘟病均有良好的防效,联合应用显著提高防治效果,对姜瘟病防治率达到86%以上,减少大姜损失率达35%。
基于空间栅格法的最大Lyapunov指数算法研究
爱波,王基,,
电子学报 , 2012, DOI: 10.3969/j.issn.0372-2112.2012.09.026
Abstract: 最大Lyapunov指数是判断时间序列是否为混沌的一个重要判据,但传统方法求解的计算量很大,所需时间较长,导致在工程实际应用中受到限制.本文提出了基于空间栅格法的最大Lyapunov指数的改进算法,该方法将重构后的整个相空间进行分割,形成多个小空间,搜索邻近点时只需在其子空间内进行搜索,可以大大提高搜索速度.仿真实验表明改进的邻近点搜索方法无论在有噪声情况下还是在无噪声情况下都具有良好的鲁棒性,可以快速而有效地实现参考点邻域的搜索,极大的缩短了计算时间,且易于编程实现,使混沌信号特征指数的在线提取成为了可能.
NaCl胁迫对5个桂花品种叶片超微结构的影响
,,,,施婷婷,王良桂
- , 2018,
Abstract: 该研究以5个桂花品种为材料,以Hoagland培养液为对照,设计2个NaCl含量(70、100 mmol/L)处理10 d后利用透射电镜和扫描电镜观察各处理不同品种的叶片超微结构特征,以明确桂花品种对耐NaCl胁迫的解剖结构响应机制。结果显示:(1)透射电镜观察发现:随NaCl 胁迫程度的加强,5个桂花品种叶肉细胞中叶绿体结构受到不同程度地破坏;70 mmol/L NaCl处理后,5个品种的细胞核基本保持正常,而100 mmol/L NaCl处理后核内染色质发生降解;随着NaCl胁迫程度的加强,5个桂花品种的类囊体片层结构中嗜锇颗粒明显增多;在膜结构方面,大叶银桂的叶肉细胞被破坏程度最为严重,叶绿体膜被破坏,叶绿体形状基本不能辨认。(2)扫描电镜观察结果显示:随着NaCl浓度的增大,5个品种叶片表面的气孔密度不断增大,而张开气孔的密度却不断减小,且叶肉细胞体积均缩小;‘大叶银桂’、‘笑秋风’、‘晚籽银桂’的栅栏组织占叶厚的比重随NaCl胁迫浓度的增大而升高,‘潢川金桂’和‘紫梗籽银桂’的栅栏组织占叶厚的比重则随NaCl胁迫浓度的增大而呈先升高后降低的趋势。研究表明,NaCl胁迫对桂花叶片细胞叶绿体、细胞核等的超微结构会造成损伤,且NaCl胁迫浓度越高损伤越明显。该试验可初步判断‘大叶银桂’、‘笑秋风’、‘晚籽银桂’的耐盐性略高于‘潢川金桂’和‘紫梗籽银桂’。
交联壳聚糖/聚乙烯醇的制备及其在竹材中的构建
, 吴华平, NAYEBARE Kakwara Prosper, 饶瑾, 张艳, 孙芳利
- , 2018, DOI: 10.13360/j.Issn.2096-1359.2018.03.010
Abstract: 以戊二醛为交联剂制备壳聚糖/聚乙烯醇互穿聚合物,并对其溶胀性进行表征。采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)和傅里叶变换红外光谱(FT-IR)研究聚合物的微观形貌和化学结构特征。将戊二醛、壳聚糖及聚乙烯醇混合后通过真空浸渍的方式注入竹材中并发生交联反应,测试处理材的干缩湿胀和防霉防腐性能。结果表明:壳聚糖可均匀分散在聚乙烯醇中,成膜均匀,两者相容性较好; 处理材在浸水-干燥3次循环下干缩率为6.9%~7.4%,在吸湿-干燥3次循环下的干缩率为1.4%~1.5%,吸水和吸湿抗胀率最高达34.5%; 壳聚糖/聚乙烯醇互穿聚合物在竹材中的构建提高了竹材的防霉和防腐效果。未处理材在试验开始后霉菌便迅速长满,处理材霉菌孢子萌发推迟,生长缓慢,处理后竹材经褐腐菌密粘褶菌和白腐菌彩绒革盖菌侵染后的质量损失率为10.0%和5.4%,与未处理材相比分别减少了8.0%和8.1%。竹材内原位构建壳聚糖/聚乙烯醇聚合物网络,既能够提高竹材的尺寸稳定性,又增加了竹材的防霉和防腐性能,同时为解决竹材尺寸稳定性差和易霉变腐朽问题提供新途径。
The interpenetrating polymer of chitosan and poly(vinyl alcohol)crosslinked by the glutaraldehyde(GA)was prepared, and the swelling properties were evaluated. Morphological and chemical structures of the polymers were investigated by the scanning electron microscopy(SEM), transmission electron microscopy(TEM)and Fourier transform infrared spectroscopy(FT-IR), respectively. The formulation of the polymer was composed of glutaraldehyde, chitosan and poly(vinyl alcohol), which was injected into bamboo by using the vacuum impregnation method and followed by a crosslinking reaction under a proper temperature. The shrinkage and swelling, mold and decay resistance of the treated material were investigated. Results are presented as follows: the chitosan can be evenly dispersed in the poly(vinyl alcohol), forming a uniform polymer film, indicating that the chitosan and poly(vinyl alcohol)have good compatibility in the crosslinked system; shrinkage values of the treated bamboo were in the range of 6.9%-7.4% under water-dry cycles and 1.4%-1.5% under moisture-dry cycles, with an anti-swelling efficiency of 34.5%; the construction of the glutaraldehyde crosslinked chitosan/poly(vinyl alcohol)interpenetrating polymer can improve the mold and decay resistance of bamboo. The untreated bamboo was quickly covered with mold at the beginning of the experiment, while the spores germinated and developed slowly on the treated bamboo. In addition, the treated bamboo resisted Gloeophyllun trabeum and Trametes versicolor effectively. The mass losses of the treated bamboo were 10.0% and 5.4%, respectively, which decreased by 8.0% and 8.1% compared with the untreated controls. The in-situ construction of the chitosan/poly(vinyl alcohol)polymer network in the bamboo not only increased the dimensional stability of bamboo, but also prevented bamboo from decay and mold, which provided a novel method for simultaneously solving the problems of dimensional instability and fungi attacking. Further research in this field will be focused on prolonging the service life of bamboo, as well as widening the application of
甲基丙烯酸羟乙酯/甲基丙烯酸甲酯交联聚合物在木材中原位构建及对其尺寸稳定性影响
Dimensional Stability Improvement of Wood Via in situ Construction of Polyhydroxyethyl Methylacrylate and Polymethyl Methylacrylate Networks

吴华平,饶瑾,,刘庭菘,孙芳利
- , 2018, DOI: 10.3969/j.issn.1001-7461.2018.04.31
Abstract: 以甲基丙烯酸羟乙酯(HEMA)和甲基丙烯酸甲酯(MMA)2种单体为原料,在过硫酸铵(APS)和偶氮二异丁腈(AIBN)的引发下,通过N-N?-亚甲基双丙烯酰胺(N,N?-MBA)的交联作用,在木材中原位构建交联聚合物网络体系,改善其因干缩湿胀引起的变形和开裂,提高尺寸稳定性。通过扫描电镜发现,HEMA和MMA经聚合和交联反应后构建贯穿木材细胞腔和细胞壁的网络结构,形成的P(HEMA/MMA)交联聚合物附着在木材薄壁组织并堵塞细胞壁纹孔。木材经3次吸湿-干燥和吸水-干燥循环试验,结果表明,在第1次吸湿-干燥循环中的膨胀率和抗胀率分别为1.6%和65.3%;在吸水-干燥循环试验中,吸水膨胀率和抗胀率分别为8.5%和37.0%。经P(HEMA/MMA)改性处理的木材能够在一定程度上提高木材的尺寸稳定性。
In this study,the chemical modification of wood was explored based on ??in situ ??construction of polyhydroxyethyl methylacrylate and polymethyl methylacrylate networks (P(HEMA/MMA)) to improve the property of dimensional stability.Initiated by ammonium persulfate (APS) and azobisisobutyronitrile (AIBN),monomers of HEMA and MMA were used to construct a crosspolymer network through cross-linking of N,N′-methylenebisacrylamide (N,N′-MBA).SEM revealed that P(HEMA/MMA) went through cell cavities and cell walls,which attached to wood parenchyma and blocks pits on cell wall.The dimensional stability was tested under three water soaking or moistening and drying cycles.The results showed that swelling ratio and anti-swelling ratio reached 1.6% and 65.3% in the first moisture absorption cycle,respectively,and 8.5% and 37.0% of the first cycle water aborsation,respectively,which indicated that the treatment of P(HEMA/MMA) improved dimensional stability of wood to some extent
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