超长结构地下室外墙混凝土裂缝的控制

对超长结构地下室外墙板混凝土裂缝的控制,是施工中的一大难题。经实验研究,从"抗"、"放"二方面入手,即采用抗裂筋、混凝土掺外加剂以及加强保温、保湿养护等技术工艺后,使超长结构地下室外墙板混凝土裂缝问题得到了有效的控制。     

四川盆西平原区裸土扬尘中Pb、Cd化学形态的生物有效性

为探究四川盆西平原区裸土扬尘中Pb、Cd总质量分数与其生物有效性的规律,在构建的"阳离子型污染物土壤表层运移行为研究系统"内进行模拟起尘试验,对土壤样品进行Pb、Cd模拟污染试验,结果表明:试验条件下,四川盆西平原区裸土扬尘颗粒物中Pb、Cd的总质量分数随着粒径的减小而增大,其中Pb的化学形态以碳酸盐结合态为主(44....     

Solution-phase chemical route to branched single-crystalline CdS nanoarchitectures and their field emission property

A facile solution chemical method is developed to prepare hierarchical branched single-crystalline CdS architectures. A mechanism of “nucleate-aggregate-grow-ripen-separate” process is proposed to illustrate the growth of the CdS architectures. The obtained branched CdS architectures exhibit superior FE properties with the lower turn-on field (Eto) of 7.1 V μm⁻¹ at a current density of 10 μA cm⁻², and threshold field (Ethr) of 8.3 V μm⁻¹ at a current density of 100 μA cm⁻², which shows that the obtained products have greatly potential application as FE devices.     

关于人工岛设计中的研究方法探讨

该文以海口市新埠岛概念性详细规划投标方案为例,浅谈在城市设计过程中人工岛设计所应关注的研究方面和设计程序;探讨在今后的海岛设计中越来越多牵扯到填海或海岸线整治方面的情况时,如何有效地进行定位研究,以推导出更合理的设计方案。     

特高压带电作业绝缘工具操作冲击放电特性及试验电极优化

目前检测机构对特高压带电作业绝缘工具开展操作冲击耐压试验时,电极布置仍沿用低电压等级标准,但试验电压和放电间距大大增加,经常出现绝缘工具间、试验电极对大地或周边构架等非试验通道放电的情况。开展了典型作业工况及试验工况下带电作业用绝缘工具标准波头操作冲击放电特性试验,并对试验工况下放电路径进行统计,提出了采用8分裂U型模拟导线的优化方案,并进行了试验验证,研究结果表明：采用8分裂U型模拟导线可显著降低非试验通道分散放电的概率;对多个试品同时进行试验时,由于存在空气间隙拉弧,试品挂接的水平间距建议不小于5 m;试验电极改进后绝缘杆6.3 m放电电压为2 417 kV,较标准电极增加6.9%,较典型作业工况下最低放电电压增加32.1%,进行绝缘工具耐压试验时建议根据作业工况的耐压要求对试验电压进行修正。     

蓝宝石衬底上原子级光滑AlN外延层的MOCVD生长

在蓝宝石衬底表面无氮化、低Ⅴ/Ⅲ比的情况下,采用1200℃的衬底温度、5kPa反应室气压,用MOCVD方法在蓝宝石衬底上生长出了表面原子级光滑的AlN外延层.原子力显微镜测试表明其平均粗糙度为0.44nm,X射线衍射(0002)回摆曲线FWHM为166".实验结果和分析表明,极性和气相反应是影响AlN表面形貌的主要原因.以原子级光滑的AlN为模板生长出了高质量的高Al组分的n型AlGaN,证实了AlN模板具有较好的质量.     

MasterDrive变频器使用外加斜坡给定的研究与应用

西门子MasterDrive变频器内部带有一个复杂功能的斜坡发生器,用于将阶跃给定增加斜坡后发给速度调节器。在某些场合比如设备需要复杂起动特性的时候,变频器需要接收外加的带斜坡的速度给定,这就需要对其进行特殊的设置。本文对外加含斜坡速度给定信号进行了分析,并提出了处理方法,最后举例说明了该方法的实际应用情况。     

Endo/Lysosome‐Escapable Delivery Depot for Improving BBB Transcytosis and Neuron Targeted Therapy of Alzheimer's Disease

The effective treatment of Alzheimer's disease (AD) is hindered due to the hard blood–brain barrier (BBB) penetration and non‐selective distribution of drugs in the brain. Moreover, the complicated pathological mechanism of AD involves various pathway dysfunctions that limit the effectiveness of a single therapeutic drug. Herein, a dendrigraft poly‐l ‐lysines (DGL)‐based siRNA and D peptide (Dp) loaded nanoparticle is designed that could target and penetrate through the BBB, enter the brain parenchyma, and further accumulate at the AD lesion. In this system, T7 peptide, which specifically targets transferrin receptors on the BBB, is linked to DGL via acid‐cleavable long polyethylene glycol (PEG) to achieve high internalization, quick escape from endo/lysosome, and effective transcytosis. Then, the Tet1, which specifically targets diseased neurons, is modified onto DGL by short PEG. After being exposed, Tet1 could drive the nanoparticles to the AD lesion and release the drugs. As a result, the production of β amyloid plaques (Aβ) is inhibited. Neurotoxicity induced by Aβ plaques and tau proten phosphorylation (p‐tau) tangle is also alleviated, and the cognition of AD mice is significantly improved. Overall, this system programmatically targets BBB and neurons, thus, significantly enhances the intracephalic drug accumulation and AD treatment efficacy.