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91.
The effect of infrared radiation on the etching characteristics of CR-39 plastic track recorder has been studied. CR-39, which is commonly employed in cosmic rays studies is found to be affected by IR radiations. The changes in the bulk etch rate, in the track etch rate and in etching efficiency due to infrared radiation exposure of CR-39 are discussed on the basis of scission and cross linking during infrared exposure. 相似文献
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Natalie Boehnke Santiago Correa Liangliang Hao Wade Wang Joelle P. Straehla Sangeeta N. Bhatia Paula T. Hammond 《Angewandte Chemie (International ed. in English)》2020,59(7):2776-2783
Layer‐by‐layer nanoparticles (NPs) are modular drug delivery vehicles that incorporate multiple functional materials through sequential deposition of polyelectrolytes onto charged nanoparticle cores. Herein, we combined the multicomponent features and tumor targeting capabilities of layer‐by‐layer assembly with functional biosensing peptides to create a new class of nanotheranostics. These NPs encapsulate a high weight percentage of siRNA while also carrying a synthetic biosensing peptide on the surface that is cleaved into a urinary reporter upon exposure to specific proteases overexpressed in the tumor microenvironment. Importantly, this biosensor reports back on a molecular signature characteristic to metastatic tumors and associated with poor prognosis, MMP9 protease overexpression. This nanotheranostic mediates noninvasive urinary‐based diagnostics in mouse models of three different cancers with simultaneous gene silencing in flank and metastatic mouse models of ovarian cancer. 相似文献
94.
Sangeeta Prasher Surinder Singh 《International Journal of Polymer Analysis and Characterization》2014,19(3):204-211
Variations in dielectric, optical, and structural properties of Lexan and Kapton-H irradiated to 80 MeV O6+ ion beam were analyzed at different fluences ranging from 1011 to 1013 ions/cm2 with a scanned beam current of 1 pnA. The structural modifications were characterized with the help of FT-IR and UV-vis spectroscopies. The electrical properties were investigated through capacitance and dielectric loss variations in ion-irradiated and pristine polymers at different frequencies. UV-vis absorption analysis indicates a decrease in the band gap energy in the two polymers. However, the decrease is much more prominent in Lexan (30%) than in Kapton-H (2.5%). The dielectric constant does not show appreciable variations after ion irradiation; however, a small increase has been noticed. An overall increase in the intensities of some typical bonds and stretching was observed in the FT-IR spectra of the pristine and ion-irradiated polymers. 相似文献
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An AFM study is reported on swift heavy irradiated Si/SiO2 substrates which have been etched by aqueous hydrofluoric acid solution leading to ion tracks in which ferrofluids have been deposited leading to tunable electronic materials with pores in oxide on silicon (TEMPOS) structure. Two ferrofluids with different carrier fluids (aqueous and non-aqueous) have been deposited in the tracks. Atomic force microscopy has been used to study the empty as well as filled tracks. Since the ferrofluids contain iron oxide particles, there is a possibility of agglomeration of these particles inside and outside the tracks. Surface area and pore volume of the tracks have been measured by Brunauer-Emmett-Teller (BET) method. The track properties (empty and filled) as observed by AFM have been correlated with BET measurements. 相似文献
98.
Sangeeta Yadav Ouissam ElBakouri Kjell Jorner Hui Tong Christian Dahlstrand Miquel Sol Henrik Ottosson 《化学:亚洲杂志》2019,14(10):1870-1878
Due to the reversal in electron counts for aromaticity and antiaromaticity in the closed‐shell singlet state (normally ground state, S0) and lowest ππ* triplet state (T1 or T0), as given by Hückel's and Baird's rules, respectively, fulvenes are influenced by their substituents in the opposite manner in the T1 and S0 states. This effect is caused by a reversal in the dipole moment when going from S0 to T1 as fulvenes adapt to the difference in electron counts for aromaticity in various states; they are aromatic chameleons. Thus, a substituent pattern that enhances (reduces) fulvene aromaticity in S0 reduces (enhances) aromaticity in T1, allowing for rationalizations of the triplet state energies (ET) of substituted fulvenes. Through quantum chemical calculations, we now assess which substituents and which positions on the pentafulvene core are the most powerful for designing compounds with low or inverted ET. As a means to increase the π‐electron withdrawing capacity of cyano groups, we found that protonation at the cyano N atoms of 6,6‐dicyanopentafulvenes can be a route to on‐demand formation of a fulvenium dication with a triplet ground state (T0). The five‐membered ring of this species is markedly Baird‐aromatic, although less than the cyclopentadienyl cation known to have a Baird‐aromatic T0 state. 相似文献
99.
研究了一类具有不同发生率的无线传感网络蠕虫传播模型的延迟动力学行为。由于在监测节点隔离不稳定节点需要消耗一定的时间,在模型中考虑了处理时滞。通过分析相应特征方程根的分布情况,得到了平衡点存在性、模型局部稳定性和Hopf分岔存在的充分性条件。通过构造合适的李雅普诺夫函数,证明了蠕虫病毒平衡点的全局稳定性。数值仿真实验验证了理论分析结果的正确性。仿真结果表明,当处理时滞的值越过关键值时,网络中的蠕虫传播将失去控制,发现无线传感网络的覆盖范围是控制蠕虫传播和保证无线传感网络安全最为重要的因素之一。并通过仿真发现消除模型混沌状态的一些关键参数,其中非线性发生率β S I I + 1 是控制蠕虫病毒传播、保证无线传感网络安全的最佳选择。 相似文献
100.
In order to synthesize YBa2Cu3O7−y
powder, we first coprecipitate yttrium and barium by adding ammonium carbonate to a solution of barium and yttrium chlorides
mixed in the 2:1 ratio at the molar level. Ceramics, prepared from powders obtained by calcining the coprecipitated powder
with copper oxide, exhibits a very sharp drop in resistivity near 110 K with T
c
midpoint
of 107 K and a resistivity anomaly at 260 K. 相似文献