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Ceratovacuna lanigera Zehntner is a major leaf pest of sugarcane. Widely distributed, it affects both the yield and quality of sugarcane in China. This study aimed to assess real yield and sugar yield losses, and the effect of C. lanigera damage on emergence of newly planted and ratoon cane under current production levels. Field experiments were carried out from 2014 to 2016 in Yunnan Province China. At maturity, plants were harvested and weighed to determine yield, and the effect on sugarcane quality and sucrose content analyzed. Real yield decreased by average of 46,185 kg hm−2 (range: 37,545–61,845 kg hm−2) in damaged versus undamaged areas, with an average yield loss rate of 35.9% (28.5–45.7%). Juice yield decreased by an average of 3.01% (2.4–4.13%) and sucrose content by 6.38% (5.48–8.16%). Juice brix decreased by an average of 7.66°BX (6.95–9.05°BX) and juice gravity purity by 12.35% (8.43–19.97%). In contrast, the reducing sugar content increased by an average of 1.21% (1.01–1.3%). Emergence rates of newly planted cane decreased by an average of 26.0% (24.7–27.3%). The emergence number of ratoon cane decreased by 66,834 hm2 (57,429–76,238 hm−2) and relative emergence loss rates of ratoon cane decreased by an average of 57.8% (57.6–58.0%). These findings confirm that C. lanigera damage severely affects sugarcane yield and quality in Yunnan Province. The results will help the implementation of effective control measures, thereby supporting sustainable development of the Chinese sugar industry.
The endoparasitoid Microplitis prodeniae Rao and Chandry is an important potential augmentative biological control agent for lepidopteran pests of vegetables and tobacco. However, cold storage of pupae is required to ensure that sufficient parasitoids are available when they are needed in the field. In this study, pupae were maintained at 0, 4 or 10°C for 5–50 days after which the adults were evaluated for emergence, pre-emergence period, sex ratio, female longevity, oviposition period, and fecundity. Cold storage did not affect the pre-emergence period or proportion of females; however, there was a significant reduction in emergence, female longevity, oviposition period, and fecundity with increased exposure to cold. The pre-emergence period was approximately 5 days, and approximately 50% of the emergent parasitoids were females. A cold storage regime of 10 days at 10°C had no effect on the parasitoids and adult emergence was greater than 50% even after 20 days at 10°C. There was no carryover of the cold treatment from parental to F1 and F2 generations. Thus, M. prodeniae can be stockpiled for field release by exposing the pupae to a cold regime and subsequently holding them for adult emergence at 28°C.
A new approach is proposed to analyze Bremsstrahlung X-rays that are emitted from laser-produced plasmas (LPP) and are measured by a stack type spectrometer. This new method is based on a spectral tomographic reconstruction concept with the variational principle for optimization, without referring to the electron energy distribution of a plasma. This approach is applied to the analysis of some experimental data obtained at a few major laser facilities to demonstrate the applicability of the method. Slope temperatures of X-rays from LPP are determined with a two-temperature model, showing different spectral characteristics of X-rays depending on laser properties used in the experiments.
The self-constructed Super-Light telescope of the National Central University is now ready for open use. Systematic studies of RR Lyraes stars and other variables are outlined and some preliminary results are introduced.
Wurtzite GaN films irradiated at room temperature with 308 MeV 129Xe35+ or 230 MeV 208Pb27+ ions have been studied by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The three-dimensional AFM images showed that swellings of the GaN films were caused by the ion irradiations at very low fluences. In comparison with the Xe ions, the Pb ions led to a much more pronounced swelling. The XPS results indicated that after the Xe and Pb irradiations, the contents of Ga and N dangling bonds in the GaN increased, and the contents of Ga-O and N-O bonds in the surface layer also increased. In the case of the Pb irradiation, a peak associated with the defect of interstitial N was detected in the N 1s core-level spectrum, implying the formation of N2 bubbles close to the GaN surface. However, no homonuclear Ga-Ga bond was found according to the related Ga 3d spectrum. The dramatic experimental results are discussed and the distinct difference of irradiation damages in GaN induced individually by the Xe and Pb ions is analyzed.
CNx films with x around 1.0 have been made by inverted cylindrical DC magnetron sputtering. RBS, XPS, IR spectroscopy, ERD and SEM were used to characterize the composition and bonding properties of the films, while X-ray diffraction was used for crystal structure determination. XPS data indicated the existence of the tetrahedral C3N4 phase in the CNx films, which was consistent with the C-N single bond suggested by IR spectra. The annealing effect on CNx films will also be discussed.
In this paper, we will report fabrication and structure study of single crystal β-SiC film on Si substrate by hot-filament chemical vapor deposition (HFC VD). The reaction sources are hydrogen-diluted methane(CH4) and Silane(SiH4). The wafer surface temperature is about 650°C. The typical growth rate is 200nm/h. Raman scattering spectrum shows a peak centering at 960cm-1 with a full width at half magnitude (FWHM) of 75cm-1. At room temperature, the photoluminescence spectrum gives a wide band at 580nm (2.2eV) with a FWHM of 55nm. Fourier transmission infrared (FT-IR) spectrum exhibits an absorption peak at 12.6 μm XRD and XPS analysis indicate that the epilayer is a stoichiometrical single crystal cubic silicon carbide film.
This paper reports the results of a study to integrate a metal-parylene interconnection system. The advantages and issues are highlighted. Fabrication steps for packaging geometries as well as proposed fabrication steps for VLSI applications are discussed. The relevant material properties for interconnection system design have been compiled.
We report the recent progress in type-II interband cascade (IC) lasers, For the 4.2-pm devices, lasing was observed up to 210 K, and the threshold density was only 95 A/cm2at 90 K and 284 A/cm2at 200 K. For the 4.5-μm lasers, the internal loss was only 11.6 cm−1 and the internal quantum efficiency was 460% at 90 K. We have also demonstrated the first dual-wavelength type-II IC lasers at 4.482 and 4.568 μm.
The nucleus diameter/cell diameter (N/C) ratio and morphological characteristics of the haemocytes of the snail Babylonia areolata were studied using microscopy. Our results revealed two major types of haemocytes, namely granulocytes and hyalinocytes. In granulocytes, the cytoplasm was purplish red with Wright's staining, but it was blue in hyalinocytes. Hyalinocytes were smaller than granulocytes and had a higher N/C ratio. The granulocytes were sub-categorized into type I granulocytes and type II granulocytes based on the shape and the number of granules. Hyalinocytes were sub-categorized into large and small hyalinocytes based on the diameter and N/C ratio. Snails with a shell length from 2.7 to 3.3 cm showed no differences in the abundance of haemocytes.
Efficient generation regime with a high power output has been experimentally realized in a klystron-like relativistic backward wave oscillator, in which a modulation cavity is inserted between the slow wave structure to decrease the energy spread of modulated beam electrons, and an extraction cavity is employed at the end of the slow wave structure to further recover energy from the electron beam. At a guiding magnetic field of 2.2 T, a microwave pulse with power of 6.5 GW, frequency of 4.26 GHz, pulse duration of 38 ns, and efficiency of 36% was generated when the diode voltage was 1.1 MV, and diode current was 16.4 kA. When the diode voltage was 820 kV, efficiency up to 47% with microwave power 4.4 GW was also realized experimentally.
The field distribution and the restraint effect of multipactor and plasma discharge on the periodic triangular surface have been theoretically and experimentally analyzed. It has been found by computational and simulative analysis that the periodic profile can quickly restrain or weaken multipactor and plasma discharge in low pressure within several microwave periods. Considering the field enhancement, increasing the slope angle, advancing the electric field, and lowering the frequency can enhance the multipactor suppression. X-band giga-watt high power microwave experiment with 20 ns short pulse was conducted. It was demonstrated that the periodic profile can effectively improve the breakdown threshold and slower the speed of tail erosion.
The aim of this work is to study the effect of Nb element doping on the microstructure and electrical properties of lead zirconate stannum titanate (PZST) ceramic and to improve phase transition properties of PZST. Nb-doped Pb(Zr,Sn,Ti)O3 ceramic samples were prepared by the conventional mixed oxide method. Phase transitions induced by temperature, pressure, and electric field were measured with electric dielectric permittivity, hydrostatic pressure, and hysteresis. The microstructure of the samples was observed by electron scanning microscope to discuss the effect of Nb doping on PZST ceramics. The experiment results indicated that the remnant polarization (Pr), dielectric constant, phase transition, and microstructure were strongly dependent on Nb doping content.
A vircator with a coaxial cavity has the potential to increase the beam–microwave conversion efficiency. According to the E-field distribution pattern of the modes in the anode cavity of a coaxial vircator, the resonant frequency band of the injected electron beam and the lowest two operating modes are derived. The main frequency of the virtual cathode is also deduced. The optimal operating frequency and high-efficiency designing method of a coaxial cavity vircator is discussed. An experimental setup is designed and built to test the high-power microwave (HPM) generation mechanism described by theoretical analysis as well as increase the power efficiency. HPM frequency obtained in the experiment is in good agreement with the analysis. The power and energy efficiencies obtained in the experiment are, respectively, 8.7% and 6.8% with 50 ns pulse width. Frequency and phase stable HPM radiation is observed as well as pulse shortening is evidently depressed.
Copper- and yttrium-rich YBa2Cu3O7 bulk superconductors have been prepared by mixing copper oxide or yttrium oxide in nitric acid and adding the solution to premade stoichiometric YBa2Cu3O7 followed by annealing. In contrast to materials made by mixing oxide powders, both samples contain copper-rich defects spread homogeneously throughout the grains, either small platelet copper oxide precipitates or bundles of planar defects (Cu–O double planes). These materials also show large magnetic hysteresis at 77 K, comparable to the results obtained from decomposed YBa2Cu4O8. This implies that small copper oxide precipitates and bundles of planar defects are strong flux pinners, and indicates a processing route to producing large amounts of strongly intragranular pinned superconductors. However, the materials also show clean grain boundaries, so an equally valid interpretation is that there is a substantial component of intergranular superconductivity in field, enhancing the effective circuit size to a value far larger than the grain size.
A range of copper-rich bulk YBa2Cu3+xO7+y superconductors have been prepared by mixing excess copper oxide in the initial material and characterized for their magnetic properties and microstructure. The microstructure of the materials exhibits a high density of planar defects at the grain boundaries and a grain boundary amorphous phase. There is a small increase in the magnetic Jc at 4.5 K but a decrease compared to a conventional material at 77 K, and there is no correlation of the magnetic Jc with the twin boundary density. The change in Jc can be understood if the grain boundary pinning is strong at 4.5 K but weak at 77 K. Data obtained using a very wide range of different microstructure characterization techniques clearly indicate the dangers of relying on only one technique to obtain a full picture of the material.
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