Comparative investigation of InP/InGaAs heterostructure-emitter tunneling and superlattice bipolar transistors

In this article, the characteristics of InP/InGaAs heterostructure-emitter bipolar transistors with 30 n-InP layer tunneling layers and a five-period InP/InGaAs superlattice are demonstrated and comparatively investigated by experimentally results and analysis. In the three devices, a 200 Å n-In_0.53Ga_0.47As layer together with an n-InP tunneling emitter layer (or n-InP/n-InGaAs superlattice) forms heterostructure emitter to decrease collector-emitter offset voltage. The results exhibits that the largest collector current and current gain are obtained for the tunneling transistor with a 30 Å n-InP tunneling emitter layer. On the other hand, some of holes injecting from base to emitter will be blocked at n-InP/n-InGaAs heterojunction due to the relatively small hole transmission coefficient in superlattice device, which will result in a considerable base recombination current in the n-InGaAs layer. Therefore, the collector current and current gain of the superlattice device are the smallest values among of the devices.     

Indium-mediated allenylation of arylacyl bromides in a route for the synthesis of substituted furans

A three-step, single purification procedure has been developed for the concise synthesis of substituted furans from arylacyl bromides.     

Age determination of a 75Se gamma radiography source for nuclear forensics

Journal of Radioanalytical and Nuclear Chemistry - Two methods were used to evaluate the age of 75Se sealed source material. Both methods utilized gamma spectroscopy to determine the quantity of...     

HMM-based ball hitting event exploration system for broadcast baseball video

With the dramatic growth of fandom population, a considerable amount of research efforts have been devoted to baseball video processing. However, little work focuses on the detailed follow-ups of ball hitting events. This paper proposes a HMM-based ball hitting event exploration system for broadcast baseball video. Utilizing the strictly-defined layout of the baseball field, the proposed system first detects the game-specific spatial patterns in the field, such as the field lines, the bases, the pitch mound, etc. Then, the play region—the currently camera-focused region of the baseball field is identified for frame type classification. Since the temporal patterns of presenting the game progress follow a prototypical order, we consider the classified frame types as observation symbols and recognize ball hitting events using HMM. Experiments conducted on broadcast baseball video show encouraging results in frame type classification and ball hitting event recognition. Three practical applications, including highlight clip extraction by user-designated query, storyboard construction, and similar event retrieval, are introduced to address the applicability of our system.     

Engineered Bifunctional Luminescent Pillared-Layer Frameworks for Adsorption of CO2 and Sensitive Detection of Nitrobenzene in Aqueous Media

Through a dual-ligand synthetic approach, five isoreticular primitive cubic (pcu)-type pillared-layer metal–organic frameworks (MOFs), [Zn₂(dicarboxylate)₂(NI-bpy-44)] ⋅ x DMF ⋅ y H₂O, in which dicarboxylate=1,4-bdc ( 1 ), Br-1,4-bdc ( 2 ), NH₂-1,4-bdc ( 3 ), 2,6-ndc ( 4 ), and bpdc ( 5 ), have been engineered. MOFs 1 – 5 feature twofold degrees of interpenetration and have open pores of 27.0, 33.6, 36.8, 52.5, and 62.1 %, respectively. Nitrogen adsorption isotherms of activated MOFs 1′ – 5′ at 77 K all displayed type I adsorption behavior, suggesting their microporous nature. Although 1′ and 3′ – 5′ exhibited type I adsorption isotherms of CO₂ at 195 K, MOF 2′ showed a two-step gate-opening sorption isotherm of CO₂. Furthermore, MOF 3′ also had a significant influence of amine functions on CO₂ uptake at high temperature due to the CO₂–framework interactions. MOFs 1 – 5 revealed solvent-dependent fluorescence properties; their strong blue-light emissions in aqueous suspensions were efficiently quenched by trace amounts of nitrobenzene (NB), with limits of detection of 4.54, 5.73, 1.88, 2.30, and 2.26 μm , respectively, and Stern–Volmer quenching constants (K_sv) of 2.93×10³, 1.79×10³, 3.78×10³, 4.04×10³, and 3.21×10³ m ⁻¹, respectively. Of particular note, the NB-included framework, NB@ 3 , provided direct evidence of the binding sites, which showed strong host–guest π–π and hydrogen-bonding interactions beneficial for donor–acceptor electron transfer and resulting in fluorescence quenching.