首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   16篇
  免费   5篇
  国内免费   3篇
化学   18篇
力学   2篇
数学   2篇
物理学   2篇
  2022年   1篇
  2021年   1篇
  2020年   2篇
  2019年   2篇
  2018年   2篇
  2017年   2篇
  2016年   2篇
  2015年   2篇
  2014年   3篇
  2012年   1篇
  2009年   1篇
  1994年   3篇
  1992年   2篇
排序方式: 共有24条查询结果,搜索用时 78 毫秒
1.
郑金键  胡荣宗 《分析化学》1994,22(8):855-858
根据自制的OCEP-1型离子分析仪的特点,设计了一套新的住偶联装置。提高了分离容量,可以用来检测复杂混合物中的低浓度组分。用等速电泳法测定了高浓度Cl^-,Ac^-存在时的F^-。这个装置对于处理离子性组分,无论在研究工作还是实际分析工作中,都是很有用的。  相似文献   
2.
Phosphodiesterase 2 (PDE2) has been regarded as a novel target for the treatment of Alzheimer’s disease (AD). In this study, we obtained (R)-LZ77 as a hit compound with moderate PDE2 inhibitory activity (IC50 = 261.3 nM) using a high-throughput virtual screening method based on molecular dynamics. Then, we designed and synthesized 28 dihydropyranopyrazole derivatives as PDE2 inhibitors. Among them, compound (+)-11h was the most potent PDE2 inhibitor, with an IC50 value of 41.5 nM. The molecular docking of PDE2-(+)-11h reveals that the 4-(trifluoromethyl)benzyl)oxyl side chain of the compound enters the H-pocket and forms strong hydrophobic interactions with L770/L809/F862, which improves inhibitory activity. The above results may provide insight for further structural optimization of highly potent PDE2 inhibitors and may lay the foundation for their use in the treatment of AD.  相似文献   
3.
Naphthalimide has emerged as an interesting DNA intercalator and possessed attracting antitumor properties. In this context, naphthalimide group was linked to platinum(IV) core to construct a series of new mono naphthalimide platinum(IV) derivatives. The title compounds exert effective antitumor activities to the tested tumor cells lines in vitro, especially the one with propionyl chain displays comparable or even better bioactivities than platinum(II) reference drugs cisplatin and oxaliplatin. Moreover, the mono naphthalimide platinum(IV) derivative displays comparable tumor growth inhibitory competence against CT26 xenograft tumors in BALB/c mice in vivo without severe toxic effects in contrast to oxaliplatin. A dual DNA damage mechanism was proven for the title complex. Both naphthalimide ligand and the liberated platinum(II) moiety could generate DNA lesions to tumor cells synergistically and active the apoptotic pathway by up-regulating the expression of caspase 9 and caspase 3. Meanwhile, the conversion of platinum(II) drug into tetravalent form by incorporating naphthalimide moiety increases the uptake of platinum in whole cells and DNA remarkably. All these facts might be the factors for the title platinum(IV) complexes to overcome platinum(II) drug resistance. Additionally, the mono naphthalimide platinum(IV) complex could interact with human serum albumin by hydrogen bond and van der Waals force which would further influence their storage, transport and bioactivities.  相似文献   
4.
Tuning the secondary structure of polypeptide is an effective strategy to modulate the assembly behaviors of polypeptide‐based copolymers. In this study, ring‐opening polymerization of l ‐alanine (Ala) and γ‐benzyl‐l ‐glutamate (BLG) N‐carboxyanhydrides was adopted using mPEG‐NH2 as the initiator to prepare mPEG‐poly(l ‐alanine‐co‐γ‐benzyl‐l ‐glutamate) (PEAB) copolymers with various Ala to BLG ratios. 1H NMR spectra and GPC test confirmed their well‐defined chemical structures. FT‐IR spectra indicated that at the powder state, all copolymers adopted both β‐sheet and αhelical conformations. With the content of PBLG increased, the crystallization temperature and melting points of PEAB copolymers first rose then fell indicated by DSC curves. The self‐assembly of PEAB copolymers in dilute aqueous solution studied by DLS, TEM and circular dichroism spectra showed that PEAB copolymers self‐assembled into nanostructures with diverse morphologies and sizes due to distinct polypeptide conformations. Rheological analysis indicated that the alteration of the polypeptide composition can effectively modulate the modulus of PEAB assemblies in concentrated solutions. In all, copolymerization of two hydrophobic amino acid N‐carboxyanhydrides into the polypeptide block maybe an effective approach for modulating the assembly properties of PEGylated polypeptide. Besides, nanosilver‐encapsulated PEA or PEAB hydrogel showed promising antibacterial effect against Staphylococcus aureus and Bacillus subtillis. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1512–1523  相似文献   
5.
OntheConstructionofd-ContinuousModulesoverSomeSpecialRings¥ChenJinjian(GuangdongNationalInstitute)Abstract:Inthepeper,weusing...  相似文献   
6.
介绍一个研究型综合实验——二次生长法NaA沸石分子筛膜的合成与表征。实验预先利用热浸渍法在α-Al_2O_3多孔载体管外表面引入NaA沸石分子筛晶种,再通过二次生长法合成NaA沸石分子筛膜。用扫描电子显微镜和X射线衍射仪表征载体管和NaA沸石分子筛及膜的形貌和结构,并利用渗透蒸发乙醇脱水膜分离装置测试膜的分离性能。通过本实验使学生了解膜分离技术这一科学前沿领域,激发学生对科学研究的兴趣,培养学生的科研探究能力。本实验涵盖合成、表征及性能测试,知识要点多、学科覆盖面广,有利于提升学生的实践操作能力、创新意识和综合运用知识的能力。  相似文献   
7.
等速电泳法同时检测无机和有机阴离子   总被引:1,自引:1,他引:0  
本文介绍了利用自制的OCEP-1型离子分析仪,建立了以Cl-为前导,正丁酸很为尾随,8-羟基喹啉为缓冲配对离子的等速电泳分离系统的新分离分析方法,对NO_3,NO_2,F ̄-,HCOO ̄-及CH3COO ̄-进行分离和同时检测,获得满意的结果。  相似文献   
8.
9.
Lv  Juan  Wu  Gang  Liu  Ying  Li  Chang  Huang  Fan  Zhang  Yumin  Liu  Jinjian  An  Yingli  Ma  Rujiang  Shi  Linqi 《中国科学:化学(英文版)》2019,62(5):637-648
For type 1 and advanced type 2 diabetic patients, insulin replacement therapy with simulating on-demand prandial and basal insulin secretion is the best option for optimal glycemic control. However, there is no insulin delivery system yet could mimic both controlled basal insulin release and rapid prandial insulin release in response to real-time blood glucose changes. Here we reported an artificial insulin delivery system, mimicking physiological basal and prandial insulin secretion, to achieve real-time glycemic control and reduce risk of hypoglycemia. A phenylboronic acid(PBA)/galactosyl-based glucose-responsive insulin delivery system was prepared with insulin-loaded micelles embedded in hydrogel matrix. At the hyperglycemic state, both the hydrogel and micelles could swell and achieve rapid glucose-responsive release of insulin, mimicking prandial insulin secretion.When the glucose level returned to the normal state, only the micelles partially responded to glucose and still released insulin gradually. The hydrogel with increased crosslinking density could slow down the diffusion speed of insulin inside, resulting in controlled release of insulin and simulating physiological basal insulin secretion. This hydrogel-micelle composite insulin delivery system could quickly reduce the blood glucose level in a mouse model of type 1 diabetes, and maintain normal blood glucose level without hypoglycemia for about 24 h. This kind of glucose-responsive hydrogel-micelle composite may be a promising candidate for delivery of insulin in the treatment of diabetes.  相似文献   
10.
整体加筋壁板裂纹扩展轨迹模拟及控制分析   总被引:4,自引:1,他引:3  
应用有限元方法并结合裂纹扩展方向判据分析模拟了飞机整体加筋壁板裂纹的扩展轨迹,与实验结果对比证明此方法的有效性;并通过壳单元模型和粘聚区渐进损伤模型详细讨论了影响整体加筋壁板裂纹扩展的筋条参数,研究了壁板筋条对裂纹止裂的控制,并对不同参数下裂纹的应力强度因子和扩展情况作对比分析.文章所述方法和结论对于飞机整体加筋壁板的损伤容限设计具有指导意义.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号