[en] In this article we present semianalytical methods for calculating the electromagnetic field in dipole and quadrupole stripline kickers with curved plates of infinitesimal thickness. Two different methods are used to solve Laplace’s equation by reducing it either to a single or to two coupled matrix equations; they are shown to yield equivalent results. Approximate analytic solutions for the lowest order fields (dipole or quadrupole) are presented and their useful range of validity are shown. The kickers plates define a set of coupled transmission lines and the characteristic impedances of modes relevant to each configuration are calculated. The solutions are compared with those obtained from a finite element solver and found to be in good agreement. Mode matching to an external impedance determines the kicker geometry and this is discussed for both kicker types. We show that a heuristic scaling law can be used to determine the dependence of the characteristic impedance on plate thickness. The solutions found by semianalytical methods can be used as a starting point for a more detailed kicker design.

[en] Many biological, ecological, and economic systems are best described by weighted networks, as the nodes interact with each other with varying strength. However, most evolving network models studied so far are binary, the link strength being either 0 or 1. In this paper we introduce and investigate the scaling properties of a class of models which assign weights to the links as the network evolves. The combined numerical and analytical approach indicates that asymptotically the total weight distribution converges to the scaling behavior of the connectivity distribution, but this convergence is hampered by strong logarithmic corrections

[en] Sputtering can be defined as the process whereby particles leave the surface as a direct consequence of the presence of incident radiation. When particles leave the surface as a result of receiving momentum from the collision cascade induced by the incident radiation, the process is called ''physical sputtering.'' If the incoming radiation (ions, electrons, or photons) induces a chemical reaction which leads to the subsequent desorption of particles, the process could be classified as ''chemical sputtering.'' There is a number of molecules such as CH₄, CF₄, CF₃H, CF₃Cl, etc., whose binding energy to a large variety of surfaces is believed to be only a few kcal/mole. Therefore, these molecules will not remain adsorbed at room temperature. Consequently, if they are generated from surface atoms by radiation-induced processes, they will almost immediately desorb into the gas phase. This process is one type of chemical sputtering. Recent data obtained in plasma environments suggest that this type of reaction is a widely occurring phenomenon; however, few systematic quantitative investigations of the subject have been completed. As a prototype system, the chemical sputtering of silicon and Si0₂ under argon-ion bombardment in the presence of a molecular beam of XeF₂ has been investigated. Under these conditions, 25 or more silicon atoms can leave the surface per incident argon ion. About 75% of the silicon is emitted as SiF₄(gas) and the rest leaves as silicon atoms or SiF/sub x/ radicals. The total yield (silicon plus fluorine) is greater than 100 atoms/ion. The measured yields are a strong function of XeF₂ flux and a much weaker function of ion energy in the range 500--5000 eV. The chemical-sputtering yield for Si0₂ is smaller than that of silicon by about an order of magnitude, but it is still larger than the physical-sputtering yield. Moreover, Si0₂ is also sputtered by electrons

[en] For the purpose of proof-testing a system intended to remotely monitor rockfall inside a potential radioactive waste repository at Yucca Mountain, a system of seismic sub-arrays will be deployed and tested on the surface of the mountain. The goal is to identify and locate rockfall events remotely using automated data collecting and processing techniques. We install seismometers on the ground surface, generate seismic energy to simulate rockfall in underground space beneath the array, and interpret the surface response to discriminate and locate the event. Data will be analyzed using matched-field processing, a generalized beam forming method for localizing discrete signals. Software is being developed to facilitate the processing. To date, a three-component sub-array has been installed and successfully tested

[en] Pollens are potential carriers for genetically modified crops to transfer genetic materials horizontally to other plants. For phanerogams, pollen viability and cross-compatibility are critical factors for successful outcross hybridization. To evaluate this possibility, this project investigated pollen viability and pod setting rate by comparing broccoli (Brassica oleracea L. var. italica Planck) and broccoli transformed with the isopentenyl transferase (ipt) gene. Both served as pollen donors and four other varieties as pollen receptors to determine outcross rates. For pollen viability, F1 progeny was higher (p?0.05) for the cross of transgenic ipt broccoli with Li Syue significantly by FDA (fluorescein diacetate) assay. Higher successful hybrids were observed for transgenic ipt broccoli with Fu Yue, Li Syue and Green King. As pollen properties, number and grain diameter were significantly larger (p?0.05) in hybrid combinations of transgenic ipt broccoli with Li Syue and Green King significantly (p?0.05). The pod setting rates were higher while transgenic ipt broccoli served as donor plant. These results analyzing pollen properties between transgenic crops with possible outcross candidates would serve as one of those critical strategies for evaluating environmental biosafety issues for transgenic crops. (author)

[en] Biological sensory systems respond to external signals in short time and adapt to permanent environmental changes over a longer timescale to maintain high sensitivity in widely varying environments. In this work we have shown how all adaptation dynamics are intrinsically non-equilibrium and free energy is dissipated. We show that the dissipated energy is utilized to maintain adaptation accuracy. A universal relation between the energy dissipation and the optimum adaptation accuracy is established by both a general continuum model and a discrete model i n the specific case of the well-known E. coli chemo-sensory adaptation. Our study suggests that cellular level adaptations are fueled by hydrolysis of high energy biomolecules, such as ATP. The relevance of this work lies on linking the functionality of a biological system (sensory adaptation) with a concept rooted in statistical physics (energy dissipation), by a mathematical law. This has been made possible by identifying a general sensory system with a non-equilibrium steady state (a stationary state in which the probability current is not zero, but its divergence is, see figure), and then numerically and analytically solving the Fokker-Planck and Master Equations which describe the sensory adaptive system. The application of our general results to the case of E. Coli has shed light on why this system uses the high energy SAM molecule to perform adaptation, since using the more common ATP would not suffice to obtain the required adaptation accuracy.

[en] The correlation method is used to determine the period of a torsion pendulum. Calculation shows that this method cannot only suppress the disturbance of white noise, but it is also insensitive to drift and damping of the torsion pendulum. An estimate of the frequency based on this method is an approximative minimum variance unbiased estimator

[en] Thermal tantalum oxide with a thickness of 620 A was studied. The dc leakage resistance and high-frequency (1-MHz) resistance of a metal--tantalum-oxide--silicon capacitor were found to be on the order of 10⁸ and 1 Ω cm², respectively. The C-V behavior of the capacitor, with its initial states being carefully treated, was reproduced and observed to be dependent on the return voltage and hold time (at return point) of the measurement conditions. And only negative charges were observed to be responsible for the conduction current through tantalum oxide. A model with the considerations of the ac equivalent circuit and low-frequency leakage characteristic of tantalum oxide was proposed for these observations. Theoretical examples, with their parameters being suitably given according to the measured data, were shown, and they explained the experimental observations quite well. It is found that the measurement conditions and effect of the ac resistance of tantalum oxide on the determination of flat-band capacitance are important and should be carefully considered when one is interpreting the interface charges from C-V curves

[en] Food security is affected by limited arable land, growing food demand and environmental degradation. Therefore, the selection of high-yield, stable-yield and climate-resistant varieties is essential to increase and maintain wheat yield. In this study, the contribution of wheat breeding was analyzed by the data of yield of wheat in production, yield and yield composition trait of wheat regional testing, annual average temperature and annual average precipitation in Sichuan Province over 40 years. The average yield per hectare (YH) of wheat lines of regional testing increased from 4.14 t ha-1 in 1981 to 5.81 t ha-1 in 2021. By 2020, the wheat yield and planting area in Sichuan, China were 59.70 104 ha and 246.70 104 t, and the yield per hectare increased from 0.82 t ha-1 in 1952 to 4.13 t ha-1 in 2020. The lower limits of yield determinants including spikes number per hectare (SNH), grain number per spike (GNS) and thousand grain weight (TGW) were significantly increased. And the obviously shortened growth period (GD) was more beneficial for wheat to cope with the complex climate in Sichuan. These results indicate that wheat breeding has significantly elevated the stability and sensitivity of wheat to climate change, which is helpful in maintaining stability and high yield under environmental anomalies. In addition, the formation of wheat varieties has been accelerated in part on the development of breeding technology. Diversifying wheat varieties is expected to mitigate some of the negative effects of climate change.

[en] The frequency of occurrence of identical bands in superdeformed and normal-deformed nuclei is studied by carrying out a statistical analysis of a large number of rotational bands, which are generated with the reflection asymmetric shell model. The frequency of occurrence and the behaviors of identical bands revealed in the statistical analysis of the experimental bands were generally reproduced by the present theoretical simulation. This would indicate that the nuclear mean-field approximation plus the beyond mean-field one, like angular-momentum and parity projections, can explain the phenomena of identical bands even though there is no available theory that can reach the accuracy of identity between the specific identical bands. Furthermore, the octupole effect on the identical bands is discussed. The present theoretical simulation shows that more correlations may lead to more identical bands