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Application of thidiazuron (N-phenyl-N'-1,2,3-thiadiazol-5-ylurea, TDZ), a cytokinin analog, to inhibit the leaf yellowing that occurs after pinching potted rose plants, resulted in compact plants with shorter shoots and thicker internodes. Two weeks after treatment with 100 μM of TDZ, new shoots were half as long as those in control plants, and stem diameters were about 40% greater. This effect of TDZ is associated with changes in cell architecture. Although TDZ treatment stimulated ethylene production by the plants, inhibitors of ethylene biosynthesis (2-aminoethoxyvinyl glycine) or action (silver thiosulfate) did not affect the response of plants to TDZ. We found that TDZ treatment significantly suppressed the expression of bioactive gibberellic acid (GA) biosynthesis genes encoding GA3 and GA20 oxidases and slightly increased the expression of GA catabolism genes encoding GA2 oxidase. Application of GA3 and TDZ together resulted in normal elongation growth, although stem diameters were still somewhat thicker. Our results suggest that TDZ regulates shoot elongation and stem enlargement in potted rose plants through the modulation of bioactive GA biosynthesis.

As devices become more miniaturized and integrated, the heat flux density has increased, highlighting the issue of heat concentration, especially for low thermal conductivity gallium oxide (Ga2O3). This study utilizes diamond composite substrates with an AlN transition layer to assist Ga2O3 in rapid thermal dissipation. All samples were prepared using pulsed laser deposition (PLD) and annealed at 600–1000 °C. The microstructure, surface morphology, vacancy defects, and thermal characteristics of post-annealed Ga2O3 were then thoroughly investigated to determine the mechanism by which annealing temperature influences the heat transfer of heterostructures. The results demonstrate that increasing the annealing temperature can improve the crystallinity of Ga2O3 while also reducing oxygen vacancy defects from 20.6% to 9.9%. As the temperature rises to 1000 °C, the thermal conductivity of Ga2O3 reaches a maximum of 12.25 W/(m·K). However, the interface microstructure has no direct correlation with annealing temperature. At 700 °C, Ga2O3/diamond exhibits a maximum thermal boundary conductance of 127.06 MW/(m2·K). Higher temperatures (>800 °C) cause irregular mixtures to form near the heterointerface, intensifying phonon interface scattering and sharply deteriorating interfacial heat transfer. These findings contribute to a better understanding of the heterointerface thermal transfer influence mechanism and provide theoretical guidance for the thermal management design and physical analysis of Ga2O3-based power devices. [ABSTRACT FROM AUTHOR]

Humite-group minerals play a crucial role in transporting water and fluorine to the Earth's deep mantle through slab sinking. In this study, we have used Brillouin scattering to determine the single-crystal elastic constants of four natural humite-group minerals with varying H2O and fluorite contents under ambient conditions, including one chondrodite [Mg4.88Si1.94O8(OH0.78F1.22)] (F61-Chn), one humite [Mg7.03Si3.07O12(OH1.26F0.74)] (F37-Hu), and two clinohumite [Mg8.85Ti0.19Si3.93O16(OH1.11F0.89) and Mg8.63Fe0.10Ti0.24Si3.97O16(OH1.84F0.16)] (F45-Chu and F8-Chu) samples. The adiabatic bulk (KS0) and shear (G0) moduli calculated from the elastic constants using Voigt-Reuss-Hill averages are: KS0 = 120.4(3) GPa and G0 = 74.1(5) GPa for F61-Chn, KS0 = 122.4(3) GPa and G0 = 78.4(2) GPa for F37-Hu, KS0 = 126.2(3) GPa and G0 = 79.7(2) GPa for F45-Chu, and KS0 = 120.5(3) GPa and G0 = 76.8(2) GPa for F8-Chu. Our results indicate that the addition of F leads to a noticeable increase in the elasticity of clinohumite and chondrodite, which is in contrast to the effect of H2O. Although Fe has a negligible effect on the bulk modulus of clinohumite, it can produce a substantial decrease in the shear modulus. These results provide important insights into the influence of humite-group minerals on the mantle velocity structure. Furthermore, we have investigated the effects of composition on the elasticity and sound velocities of minerals along the forsterite-brucite join in the MgO-SiO2-H2O system, confirming previous observations. Increasing H2O content along the forsterite-brucite join leads to apparent reductions in the elasticity and sound velocities. The influence of Fe on the elasticity and sound velocities of these minerals has also been evaluated. [ABSTRACT FROM AUTHOR]

An ultra-wideband metal antenna with low radar cross section is proposed. The antenna adopts the metal Vivaldi as the radiation element, and utilizes a new-type frequency selective surface structure to reduce the radar cross section within the working frequency band. The frequency selective surface structure is composed of three layers of periodic planar structure and double layer medium, which has the characteristics of ultra wide bandwidth and controllable bandwidth. By changing the slot width and the width of the middle layer metal structure, can adjust the working frequency bandwidth and center frequency of the frequency selective surface structure, so as to realize the frequency bandwidth is adjustable, which can be used to reduce radar cross section of the antenna in different working frequencies.

Taking the involute spur gear pairs with profile shift as the research object, the mesh stiffness calculation models including nonlinear Hertzian contact stiffness, tooth profile curve, fillet foundation stiffness with structure coupling effect were established based on the potential energy method. Considering the influences of gear profile shifts, the calculation formulas for tooth profile curve, half tooth angle of base circle and half tooth angle of dedendum circle in mesh stiffness calculation were revised. The fillet foundation stiffness models were revised by considering tooth surface frictions. The pressure angle models of gear mesh point were derived by considering geometric eccentricity errors. The effects of profile shifted, tooth surface frictions and geometric eccentricity errors on mesh stiffness were studied. The results show that the center distance, stiffness amplitude and contact ratio of the profile shifted gear pairs have great changes. Owing to the profile shift, the moment when the direction of frictional force changes on a pair of meshing gears no longer occurs within the single tooth meshing interval, thereby affecting the characteristics of the mesh stiffness. Geometric eccentricity increases the peak-to-peak values of the mesh stiffness, and at the same time, sideband frequencies with intervals corresponding to the rotational frequencies appear in the frequency domain of the meshing stiffness. In the presence of eccentricity errors in both the driving and driven gears, a new sideband frequency arises with an interval equal to the difference in rotation frequency. Considering the combined effects of three factors, the mesh stiffness characteristics may be significantly influenced. The research results provide the references for further researches of the dynamics of profile shifted gears. [ABSTRACT FROM AUTHOR]

We present how the interaction between Al dopants and threading dislocations affects dislocation inclinations and then plays an important role in controlling residual strain in GaN-on-Si epitaxial films. When the Al concentration in the GaN epitaxial film is increased to 0.85%, the dislocations extend almost in the growth direction, contributing to a strain-free epitaxial film. We suggest that the Al atoms could substitute for Ga vacancies at the dislocation cores on the growth surface and then inhibit the dislocation inclinations. The suppressed dislocation inclinations lead to a reduced relaxation of compressive strain. The results pave a new way to control dislocation movements and strain in GaN epitaxial films on Si substrates. [ABSTRACT FROM AUTHOR]

Stratified regression models are commonly employed when study subjects may come from possibly different strata such as different medical centers, and for the situation, one common question of interest is to test the existence of the stratum effect. To address this, there exists some literature on the testing of the stratum effects under the framework of the proportional hazards model when one observes right-censored data or interval-censored data. In this paper, we consider the situation under the additive hazards model when one faces current status data, for which there does not seem to exist an established test procedure. The asymptotic distributions of the proposed test procedure are provided. Also a simulation study is performed to evaluate the performance of the proposed method and indicates that it works well for practical situations. The approach is applied to a set of real current status data from a tumorigenicity study. [ABSTRACT FROM AUTHOR]