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271.
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Chen Yang Ying Chen Dan Liu Jinfeng Wang Cheng Chen Jiemin Wang Ye Fan Shaoming Huang Weiwei Lei 《Frontiers of Physics》2018,13(4):138101
Vertically aligned γ-AlOOH nanosheets (NSs) have been successfully fabricated on flexible Al foils via a solvothermal route without morphology-directing agents. Three different reaction temperature (25, 80, and 120 ?C) and time (30 min, 45 min, and 24 h) are discussed for the growth period, which efficiently tune the density and size of the γ-AlOOH NSs. Meanwhile, the growth speed of the nanosheets confirms that dominant growth stage is seen in the initial 45 min. Furthermore, the interlayer of the γ-AlOOH NSs displays an average height of 140 nm and superhydrophilicity. By dynamic adsorption, the assynthesized γ-AlOOH NSs exhibit an outstanding NH3 adsorption capacity of up to 146 mg/g and stably excellent regeneration for 5 cycles. The mechanism of NH3 adsorption on the in-plane of the γ-AlOOH NSs is explained by the Lewis acid/base theory. The H-bond interactions among the NH3 molecules and the edge groups (-OH) further improve the capture ability of the nanosheets. 相似文献
274.
Dan Mu Jiong Sun Dept. of Math. Inner Mongolia University Hohhot 《Annals of Differential Equations》2010,(1):45-52
The problem of J-selfadjointness of the product of two nth-order J-symmetric operators on [a,b] is studied. We give a condition to ensure that the product operator is a J-selfadjoint extension. 相似文献
275.
Eric Berberich Efi Fogel Dan Halperin Kurt Mehlhorn Ron Wein 《Mathematics in Computer Science》2010,4(1):45-66
We introduce a framework for the construction, maintenance, and manipulation of arrangements of curves embedded on certain
two-dimensional orientable parametric surfaces in three-dimensional space. The framework applies to planes, cylinders, spheres,
tori, and surfaces homeomorphic to them. We reduce the effort needed to generalize existing algorithms, such as the sweep
line and zone traversal algorithms, originally designed for arrangements of bounded curves in the plane, by extensive reuse
of code. We have realized our approach as the Cgal package Arrangement_on_surface_2. We define a compact and modular interface for our framework; for a given application a required small subset of the interface
can be identified. Then, only this subset must be implemented. A companion paper describes concretizations for several types
of surfaces and curves embedded on them, and applications. This is the first implementation of a generic algorithm that can
handle arrangements on a large class of parametric surfaces. 相似文献
276.
277.
设f是一个有穷级的超越整函数,a,b,c是3个有穷复数,满足c≠0,a≠b,且n为正整数.如果a是f的Borel例外值,且Δ_c~nf(z)与f(z)IM分担b,则f(z)=a+Ae~(Bz),其中A,B为两个非零常数. 相似文献
278.
目的 分析和探讨后腹腔镜下肾部分切除术后发生尿瘘的危险因素。方法统计和分析2004-10-2013-06 行腹
腔镜下经后腹膜路径肾部分切除术后发生尿瘘的128 例肾肿瘤患者的临床资料,尿瘘严格定义为手术2d 后仍从后腹膜引流管持续引流出尿液。结果术后有14 例(10.9%)患者发生尿瘘。发生尿瘘的患者中10 例(71.4%)未行CTA 检查,术中平均出血量(232.3±86.7)ml,平均肾动脉阻断时间(28.2±7.5)min,平均住院时间(13.1±2.1)d,9 例(64.3%)术中发现集合系统破损。单因素分析提示年龄(P =0.1102)、糖尿病(P =0.0445)、肿瘤内生型生长(P =0.0835)、术前是否行CTA 检查(P=0.0137)、集合系统损伤(P=0.0935)、肾动脉阻断时间(P =0.1225)及术中出血量(P=0.0045)是发生尿瘘的危险因素;多因素分析提示糖尿病(P =0.0381)、术前是否行CTA 检查(P =0.0433)及术中出血量(P =0.0155)是术后发生尿瘘的独立危险因素。结论糖尿病、术中出血
量及术前是否行肾脏CTA 检查是后腹腔镜下肾部分切除术后发生尿瘘的独立危险因素。减少术中出血有利于术者获得清晰的操作视野,有效缝合破损的集合系统,从而防止尿瘘的发生。 相似文献
279.
Poly(vinyl alcohol)/melamine phosphate composites (PVA/MP) as a novel halogen‐free, flame‐retardant foam matrix were prepared through thermal processing, and then their thermal stability and flame retardancy were investigated by thermo‐gravimetric analysis, micro‐scale combustion calorimeter, cone calorimeter, vertical burning test, and limiting oxygen index (LOI) test. It was found that the thermal stability and combustion properties of the PVA/MP composites could be influenced by the addition of MP. Compared with the control PVA sample (B‐PVA), in the PVA/MP (75/25) composites, the temperature at 5% mass loss (T5%) decreased about 10°C, the residual chars at 600°C increased by nearly 27%, the temperature at the maximum peak heat release rate (TP) shifted from 292°C to 452°C, and the total heat released and the heat release capacity (HRC) decreased by 28% and 14%, respectively. Moreover, the PVA/MP composites could reach LOI value up to 35% and UL94 classification V‐0, showing good flame retardancy. At the same time, both Fourier transform infrared and X‐ray photoelectron spectroscopy spectra of the residual chars from the PVA/MP composites demonstrated that the catalytic effect of MP on the dehydration and decarboxylation reactions of PVA, and the chemical reactivity of MP during the chars‐forming reactions could be used to account for the changed thermal stability and flame retardancy of the PVA/MP composites. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
280.
Injectable hydrogels have attracted a lot of attention in drug delivery, however, their capacity to deliver water-insoluble or hydrophobic anti-cancer drugs is limited. Here, we developed injectable graphene oxide/graphene composite supramolecular hydrogels to deliver anti-cancer drugs. Pluronic F-127 was used to stabilize graphene oxide (GO) and reduced graphene oxide (RGO) in solution, which was mixed with α-cyclodextrin (α-CD) solution to form hydrogels. Native hydrogel was used as control. GO or RGO slightly shortened gelation time. The storage and loss moduli of the hydrogels were tracked by dynamic force measurement. The storage modulus of GO or RGO composite hydrogels was larger than that of the native hydrogel. Hydrogels were unstable in solution and eroded gradually. GO or RGO in Pluronic F-127 solution could potentially improve the solubility of the water-insoluble anti-cancer drug camptothecin (CPT), especially with large drug-loaded CPT amount. Drug release behaviors from solutions and hydrogels were characterized. The nanocomponents (GO or RGO) were able to bind more drug molecules either for CPT or for doxorubicin hydrochloride (DXR) in solution. Therefore, GO or RGO composite hydrogel could potentially enable better controlled and gentler drug release (for both CPT and DXR) than native hydrogel. 相似文献