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241.
The mixed crystal (K1-xCsx)2ZnCl4 with x = 0, 0.001, 0.01, 0.1, and 0.2 with optical quality has been grown by the Czochralski method. Using the Atomic Absorption Spectroscopy (AAS) and Energy Dispersive Spectroscopy (EDS), we determined the amount of Cs ion included in the mixed crystal. By using of DTA and DSC, we observed the change of Tc and Ti. The thermal hysteresis in the dielectric constants show strong dependence on the thermal process and on the amount of impurity which are explained by the influence of the thermal process and impurity, respectively on the creation, annihilation, and growth of discommensuration (DC).  相似文献   
242.
Two different series of new aromatic liquid crystalline (LC) polyesters were prepared from 3-phenyl-4, 4'-biphenyldicarboxylic acid (PBDA) and 1-phenyl-2, 6-naphthalenedicarboxylic acid (PNDA). PBDA and PNDA were polymerized with various aromatic diols such as hydroquinone, substituted hydroquinones, isomeric naphthalenediols and 4, 4'-biphenol, and the resulting polyesters were characterized by DSC, WAXD, and on a cross-polarizing microscope for the study of their thermal transition and crystallization properties, and mesophases formed therefrom.  相似文献   
243.
In this paper,we consider a possible modification of the de Sitter and anti-de Sitter space for the extended uncertainty principle.For the modified anti-de Sitter model we discuss the representation and wave functions of the momentum operator for a one-dimensional box problem.Also,we consider modified Snyder and anti-Snyder models for the generalized uncertainty principle.Then,we assume the Hamiltonian with different potential and solve the Heisenberg algebra for the modified(anti)-de Sitter and(anti)-Snyder models in both position and in the momentum space.  相似文献   
244.
Object detection is a significant activity in computer vision, and various approaches have been proposed to detect varied objects using deep neural networks (DNNs). However, because DNNs are computation-intensive, it is difficult to apply them to resource-constrained devices. Here, we propose an on-device object detection method using domain-specific models. In the proposed method, we define object of interest (OOI) groups that contain objects with a high frequency of appearance in specific domains. Compared with the existing DNN model, the layers of the domain-specific models are shallower and narrower, reducing the number of trainable parameters; thus, speeding up the object detection. To ensure a lightweight network design, we combine various network structures to obtain the best-performing lightweight detection model. The experimental results reveal that the size of the proposed lightweight model is 21.7 MB, which is 91.35% and 36.98% smaller than those of YOLOv3-SPP and Tiny-YOLO, respectively. The f-measure achieved on the MS COCO 2017 dataset were 18.3%, 11.9% and 20.3% higher than those of YOLOv3-SPP, Tiny-YOLO and YOLO-Nano, respectively. The results demonstrated that the lightweight model achieved higher efficiency and better performance on non-GPU devices, such as mobile devices and embedded boards, than conventional models.  相似文献   
245.
An anthracycline drug, adriamycin, was chemically conjugated onto the backbone of glycol chitosan via an acid-labile cis-aconityl linkage. The physicochemical characteristics of the glycol chitosan–adriamycin (GC–ADR) conjugates were investigated by dynamic light scattering, atomic force microscopy, and fluorescence spectroscopy. The GC–ADR conjugates were capable of forming nano-sized self-aggregates in an aqueous medium, when the adriamycin content in the conjugate was in the range of 2.0–5.0 wt.%. The self-aggregates were spherical in shape, and had mean diameters of 238–304 nm, depending on the adriamycin content. The critical aggregation concentrations of the conjugates, estimated by the fluorescence quenching method, were as low as 1.0–2.5×10−2 mg/ml. The size of self-aggregates was not affected by the polymer concentration in the range from 50 to 2,000 μg/ml, and was maintained up to 8 days in phosphate-buffered saline (pH 7.4), indicating high colloidal stability. The release of adriamycin from self-aggregates was significantly dependent on the pH of the medium due to the cis-aconityl linkage; e.g., the amount of adriamycin released for 4 days was 7.3±0.3% at pH 7, whereas it was 29.3±1.9% at pH 4. The cell viability results demonstrated that free adriamycin shows more potent cytotoxicity than the conjugates, primarily attributed to the sustained release of adriamycin from self-aggregates. In conclusion, the self-aggregates, formed by GC–ADR conjugates, might be useful for the site-specific delivery of adriamycin in a sustained manner.  相似文献   
246.
Green means go : A polyelectrolyte diode on a microchip exhibits well‐defined nonlinear rectifying behavior. This system visualizes the dynamic distribution of ions in a charged polymer phase under an electric field on a real‐time basis using fluorescence images (see picture). Multiple polyelectrolyte diodes are integrated on a microchip to produce a variety of logic gates based on ionic circuits.

  相似文献   

247.
Aerobically grown Shewanella sp. bacterial suspension drop‐coated on a disposable screen‐printed carbon electrode was found to possess electroactivity without the aid of redox mediator. Cyclic voltammetric studies revealed the characteristics of a mixed diffusion adsorption‐controlled electrochemical process for direct electron transfer at the bacteria‐modified electrode. Both FE‐SEM and ATR FT‐IR experiments were carried out to investigate the surface characteristics. The electroanalytical applicability was further demonstrated for electrocatalytic reduction of arsenite, hydrogen peroxide and nitrite. Low cost and very simple manufacturing procedure allow for the proposed bacterial sensor to be applied as disposable devices.  相似文献   
248.
Organochlorine pesticide (OCP) residues in foods have been of concern for several decades. However, the analysis of some of the OCPs and their metabolites or derivatives, such as endrin aldehyde, endrin ketone, nonachlor, etc. in fatty foods (including foods of animal and plant origin), was not commonly included in routine monitoring programme. Recently, the Stockholm Convention introduced nine plus one new persistent organic pollutants (POPs) that included chlordecone and some other OCPs. Is there a method available that can analyze both traditional OCPs, together with their metabolites and derivatives in fatty foods? Furthermore, is there a suitable method that can monitor OCPs and the newly added POPs including chlordecone in fatty foods together in a pot? This review aims to provide some background information to answer these questions.  相似文献   
249.
Al2O3/WO3/ZrO2固体强酸催化剂对正丁烷异构化的催化性能   总被引:9,自引:2,他引:9  
 通过沉淀、回流、浸渍和焙烧等步骤制备了Al2O3/WO3/ZrO2固体强酸催化剂.采用XRD,N2吸附,UV-Vis光谱,NH3-TPD和H2-TPR等技术测定了Al2O3对WO3/ZrO2催化剂的结构、表面酸性、氧化还原性及正丁烷异构化反应性能的影响.结果表明,在WO3/ZrO2中引入适量的Al2O3对其表面酸强度及酸量无显著影响,但可使催化剂中的ZrO2组分以稳定的四方相形式存在,并能有效地抑制催化剂中WO3的聚集长大,从而提高催化剂的稳定性和正丁烷异构化的转化率和选择性.添加铂于Al2O3/WO3/ZrO2中可进一步提高其催化性能.还考察了催化剂的焙烧温度、Al含量、反应温度和反应气氛对正丁烷异构化反应的影响.  相似文献   
250.
Effects of vortex pairing on particle dispersion in turbulent shear flows   总被引:4,自引:0,他引:4  
Particle dispersion in large-scale dominated turbulent shear flow is investigated numerically with special emphasis on the effects of the vortex-pairing phenomenon. The particle dispersion is visualized numerically by following the particle trajectories in a flow consisting of large vortices which are undergoing pairing interaction. The flow field is generated by a discrete vortex method. Important global and local fiow quantities from the numerical simulation compare reasonably well with experimental measurements.

For both cases of point sources with continuous particle release and an initially distributed line source, the particle dispersion results demonstrate that the extent of particle dispersion depends strongly on the Stokes number, the ratio of the particle aerodynamic response time to the characteristic time of the vortex-pairing flow field. Particles with relatively small Stokes numbers disperse laterally at approximately the saine rate as that of the fluid particles and particles with large Stokes numbers disperse much less than the fluid particles. Particles with intermediate Stokes numbers (0.5-5) may be dispersed laterally farther than the fiuid particles and may actually be flung out of the vortex structures. Due to the strong particie entrainment power, the flow during the vortex-pairing process seems to produce higher particle lateral dispersion than the pre-pairing and post-pairing flows.  相似文献   

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