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排序方式: 共有352条查询结果,搜索用时 31 毫秒
131.
132.
Copper‐64‐Alloyed Gold Nanoparticles for Cancer Imaging: Improved Radiolabel Stability and Diagnostic Accuracy 下载免费PDF全文
Dr. Yongfeng Zhao Deborah Sultan Lisa Detering Sangho Cho Dr. Guorong Sun Prof. Richard Pierce Prof. Karen L. Wooley Prof. Yongjian Liu 《Angewandte Chemie (International ed. in English)》2014,53(1):156-159
Gold nanoparticles, especially positron‐emitter‐ labeled gold nanostructures, have gained steadily increasing attention in biomedical applications. Of the radionuclides used for nanoparticle positron emission tomography imaging, radiometals such as 64Cu have been widely employed. Currently, radiolabeling through macrocyclic chelators is the most commonly used strategy. However, the radiolabel stability may be a limiting factor for further translational research. We report the integration of 64Cu into the structures of gold nanoparticles. With this approach, the specific radioactivity of the alloyed gold nanoparticles could be freely and precisely controlled by the addition of the precursor 64CuCl2 to afford sensitive detection. The direct incorporation of 64Cu into the lattice of the gold nanoparticle structure ensured the radiolabel stability for accurate localization in vivo. The superior pharmacokinetic and positron emission tomography imaging capabilities demonstrate high passive tumor targeting and contrast ratios in a mouse breast cancer model, as well as the great potential of this unique alloyed nanostructure for preclinical and translational imaging. 相似文献
133.
Aliphatic chains were introduced into the macromolecule of kraft lignin using aliphatic chlorides as esterification reagents. The hydrophobicity of esterified lignin (EL) was enhanced as compared to the original lignin. EL was further used as a macromolecular coupling agent in poly(butylene succinate)/chemi-thermomechanical pulp fiber composites. As a result, the composites with enhanced mechanical performance were obtained, and the tensile strength, impact strength, and bending strength were increased by 25.1, 22.4, and 19.3%, respectively, under 2 wt% EL-treatment (synthesized by palmitoyl chloride, –COCl/–OH = 1.5:1) in comparison with those of the specimen without any coupling agent treatment. Furthermore, the composite prepared with EL-treated fibers shows significant lower water absorption ratio than that of untreated one. A significant increase in storage modulus (E′) was observed upon the incorporation of treated fibers. Furthermore, the improved interfacial bonding between treated fibers and matrix was verified by SEM images. The shear viscosity of composite was increased by the incorporation of EL, but in general, the rheological behaviors of composites are not significantly changed. 相似文献
134.
Yu Yongjian 《International Journal of Infrared and Millimeter Waves》1993,14(8):1717-1722
In this paper is studied the effect of electron beam geometric deformation errors on the small — signal characteristics of the TE
mn
o
mode Electron Cyclotron Resonance Maser (ECRM), based on the elliptically cross—sectional e—beam deformation model. As an example, the effect of small geometric deformation errors on the TE
01
o
mode fundamental ECRM coupling coefficient is quantitatively shown. 相似文献
135.
Yu Yongjian 《International Journal of Infrared and Millimeter Waves》1990,11(4):585-594
This paper presents a theorem that connects the dispersion relation of the Electron Cyclotron Maser' and the oscillation equation of the Gyromonotron. This theorem gives us a simple way of obtaining the osscillating characteristics of the Gyromonotron provided that dispersion relation of the ECRM is given. Though the theorem is proved only with the case of ECRM and Gyromonotron, it holds for other kinds of Electron Masers, FEL4etc. and corresponding osscillators. 相似文献
136.
Yu Yongjian 《International Journal of Infrared and Millimeter Waves》1990,11(5):667-683
In this paper, we model the cyclotron-undulator hydrid instability using the kinetic theory in circular waveguide geometry, following the generalized method of the field expansion in the guiding center coordinate system; and derive in detail the coupling coefficient for a cyclotron-undulator hybrid FEL operating at the fundamental harmonic of gyration and undulation. In our discussion, the effect of the transverse structure of the radiation fields is taken into account, but the undulator is considered as an ideally longitudinal one. 相似文献
137.
A method was developed for the quantitative determination of inorganic cations and anions present in liquid crystal materials pretreated with ultraviolet irradiation by ion chromatography. The samples were irradiated at less than 20±2 °C and then pretreated with OnGuard RP and P cartridges to remove the interferential organic compounds prior to ion chromatographic analysis for both cations and anions. With a high capacity and very hydrophilic anion exchange column, four anions (fluoride, chloride, bromide, iodide) were determined in 20 min with gradient of sodium hydroxide. By employing a cation exchange column, five cations (sodium, ammonium, potassium, magnesium, calcium) could be determined in 12 min. The spiked recoveries for the cations and anions were 84.0–108.1% and 86.1–108.2%, respectively. 相似文献
138.
An apparatus constructed for measuring permeation properties of polymer membranes using a mixture of gases is described. A gas chromatographic system was applied to determine the individual transport characteristics of component gases without a vacuum line. This paper also discusses some experimental factors effecting the precision of measurement. The results show that there is a linear relationship between the permeation time and the volume of the gas permeated through the membrane within certain permeation period, which depends on the permeation rate (from 10~(-4) to 10~(-7) cm~3 (STP)/cm~2. sec. cmHg) of the membrane. The reproducibility has been found to be good with a relative standard deviation of 3.5%. This method is more sensitive, considerably faster and more convenient for determining both the permeability coefficient and the separation factor of a polymer membrane from a chromat ogram using mixed penetrant gases. 相似文献
139.
Haikuo Zhang Ruhong Li Long Chen Yingzhu Fan Hao Zhang Ruixin Zhang Lei Zheng Junbo Zhang Shouhong Ding Yongjian Wu Baochen Ma Shuoqing Zhang Dr. Tao Deng Prof. Lixin Chen Prof. Yanbin Shen Prof. Xiulin Fan 《Angewandte Chemie (International ed. in English)》2023,62(11):e202218970
Although great progress has been made in new electrolytes for lithium metal batteries (LMBs), the intrinsic relationship between electrolyte composition and cell performance remains unclear due to the lack of valid quantization method. Here, we proposed the concept of negative center of electrostatic potential (NCESP) and Mayer bond order (MBO) to describe solvent capability, which highly relate to solvation structure and oxidation potential, respectively. Based on established principles, the selected electrolyte with 1.7 M LiFSI in methoxytrimethylsilane (MOTMS)/ (trifluoromethyl)trimethylsilane (TFMTMS) shows unique hyperconjugation nature to stabilize both Li anode and high-voltage cathode. The 4.6 V 30 μm Li||4.5 mAh cm−2 lithium cobalt oxide (LCO) (low N/P ratio of 1.3) cell with our electrolyte shows stable cycling with 91 % capacity retention over 200 cycles. The bottom-up design concept of electrolyte opens up a general strategy for advancing high-voltage LMBs. 相似文献
140.
Service outsourcing has become a hot topic in both industry and academy. This paper studies the contract design problems for a service seller who consigns the service to a vendor. The vendor’s service cost parameter may or may not completely be known by the seller, which constitutes the cases of information symmetry or asymmetry. In both cases, the optimal contracts are developed to maximize the seller’s expected profit, with the consideration of contractible and non-contractible service qualities. The properties of the contract parameters are explored, along with the analysis of information rent and value of cost information. Moreover, we find that non-contractible service quality is not an issue for the service seller under cost information symmetry since a revenue-sharing type of contract can guarantee the seller’s profit. However, this result does not hold under cost information asymmetry and thus non-contractibility of the service quality indeed costs the seller. 相似文献