Adult Female Spruce Bedworm, \u3ci\u3eChoristoneura Fumiferana\u3c/i\u3e (Lepidoptera: Tortricidae), Dry Weight in Relationship to Pupal Fresh Weight and Case Diameter

(excerpt) The weights of adult insects are often measured in production and population studies in order to estimate such variables as growth rates, food conversion efficiencies, fecundity, and others. For the eastern spruce budworm, Choristoneura fumiferana (Clemens), both pupal fresh weights and pupal case diameters have been measured as indicators of adult fecundity and adult dry weights (Miller 1957). However, there are no reports explicitly showing the relationship between these metric pupal variables and adult dry weights. This is the goal of this note

The Influence of Tenure Status upon Rural Life in Eastern South Dakota

Introduction: The subject of land tenure has been of primary interest to South Dakota people for a number of years. Almost without exception, county agricultural planning committees have listed tenancy among the more important land-use problems in South Dakota. The State Agricultural Planning Committee at its February 1942, meeting requested that land tenure studies be continued by the South Dakota Agricultural Experiment Station. There has also been a considerable amount of interest in the problems of land tenure at the national level. An outstanding evidence of this concern is Farm Tendency, the report of the President’s Committee which was published in 1937. This report deals mainly with the problem of security for farmers, and in the preface it is made clear that “thousands of farmers commonly considered as owners are as insecure as tenants.” In the realm of governmental action the Farm Security Administration, acting under orders from the Congress, has helped some disadvantaged tenants to attain ownership. (See more in text)

Horace W. Slocum Journals - Accession 23

The Horace W. Slocum Journals include handwritten and typewritten accounts of Mr. Slocum’s journeys through South Carolina, North Carolina, Pennsylvania, Virginia, New York, Illinois, New Hampshire, and other states in search of rocks and minerals. Of special interest are photographs and maps of geological and mining sites in the typewritten, edited version of the journals. There is also a map index. The journals extend mainly from 1938 to 1956.https://digitalcommons.winthrop.edu/manuscriptcollection_findingaids/1037/thumbnail.jp

Quasi-infra-red fixed points and renormalisation group invariant trajectories for non-holomorphic soft supersymmetry breaking

In the MSSM the quasi-infra-red fixed point for the top-quark Yukawa coupling gives rise to specific predictions for the soft-breaking parameters. We discuss the extent to which these predictions are modified by the introduction of additional ``non-holomorphic'' soft-breaking terms. We also show that in a specific class of theories there exists an RG-invariant trajectory for the ``non-holomorphic'' terms, which can be understood using a holomorphic spurion term.Comment: 24 pages, TeX, two figures. Uses Harvmac (big) and epsf. Minor errors corrected, and the RG trajectory explained in terms of a holomorphic spurion ter

25nm Immersion Lithography at a 193nm Wavelength

The physical limitations of lithographic imaging are ultimately imposed by the refractive indices of the materials involved. At oblique collection angles, the numerical aperture of an optical system is determined by nsin(theta) , where n is the lowest material refractive index (in the absence of any refractive power through curvature). For 193nm water immersion lithography, the fluid is the limiting material, with a refractive index of near 1.44, followed by the lens material (if planar) with a refractive index near 1.56, and the photoresist, with a refractive index near 1.75. A critical goal for immersion imaging improvement is to first increase the refractive indices of the weakest link, namely the fluid or the lens material. This paper will present an approach to immersion lithography that will allow for the exploration into the extreme limits of immersion lithography by eliminating the fluid altogether. By using a solid immersion lithography (SIL) approach, we have developed a method to contact the last element of an imaging system directly to the photoresist. Furthermore, by fabricating this last element as an aluminum oxide (sapphire) prism, we can increase its refractive index to a value near 1.92. The photoresist becomes the material with the lowest refractive index and imaging becomes possible down to 28nm for a resist index of 1.75 (and 25nm for a photoresist with a refractive index of 1.93). Imaging is based on two-beam Talbot interference of a phase grating mask, illuminated with highly polarized 193nm ArF radiation. Additionally, a roadmap is presented to show the possible extension of 193nm lithography to the year 2020

Effects of Beam Pointing Instability on Two-Beam Interferometric Lithography

In a photolithographic system, the mask patterns are imaged through a set of lenses on a resist-coated wafer. The image of mask patterns physically can be viewed as the interference of the plane waves of the diffraction spectrum captured by the lens set incident on the wafer plane at a spectrum of angles. Two-beam interference fringe is the simplest format of the image. Consequently, two-beam interferometric lithography is often employed for photolithographic researches. For two-beam interferometric lithography, beam pointing instability of the illumination source can induce fringe displacement, which results in a loss of fringe contrast if it happens during the exposure. Since some extent of beam pointing instability is not avoidable, it is necessary to investigate its effects on the contrast of the interference fringe. In this paper, the effects of beam pointing instability associated with a two beam interferometric lithography setup are analyzed. Using geometrical ray tracing technique and basic interference theory, the relationship between the beam tilt angle and interference fringe displacement is established. For a beam pointing instability with random distribution, the resulted fringe contrast is directly proportional to the Fourier transform of the pointing distribution evaluated at 1/2(pi). The effect of a pointing instability with normal distribution on interference contrast is numerically investigated

A Measurement of Newton's Gravitational Constant

A precision measurement of the gravitational constant $G$ has been made using a beam balance. Special attention has been given to determining the calibration, the effect of a possible nonlinearity of the balance and the zero-point variation of the balance. The equipment, the measurements and the analysis are described in detail. The value obtained for G is 6.674252(109)(54) 10^{-11} m3 kg-1 s-2. The relative statistical and systematic uncertainties of this result are 16.3 10^{-6} and 8.1 10^{-6}, respectively.Comment: 26 pages, 20 figures, Accepted for publication by Phys. Rev.

Experimental Measurement of Photoresist Modulation Curves

An approach to measurement of resist CD response to image modulation and dose is presented. An empirical model with just three terms is used to describe this response, allowing for direct calculation of photoresist modulation curves. A thresholded latent image response model has been tested to describe CD response for both 90 nm and 45 nm geometry. An assumption of a linear optical image to photoresist latent image correlation is shown as adequate for the 90 nm case, while the 45 nm case demonstrates significant non-linear behavior. This failure indicates the inadequacy of a “resist blur” as a complete descriptive function and uncovers the need for an additional spread function in OPE-style resist models

Resist Process Window Characterization for the 45-nm Node Using an Interferometric Immersion microstepper

Projection and interference imaging modalities for application to IC microlithography were compared at the 90 nm imaging node. The basis for comparison included simulated two-dimensional image in resist, simulated resist linesize, as well as experimental resist linesize response through a wide range of dose and focus values. Using resist CD as the main response (both in simulation and experimental comparisons), the two imaging modes were found nearly equivalent, as long as a suitable Focus-Modulation conversion is used. A Focus-Modulation lookup table was generated for the 45 nm imaging node, and experimental resist response was measured using an interferometric tool. A process window was constructed to match a hypothetical projection tool, with an estimated error of prediction of 0.6 nm. A demodulated interferometric imaging technique was determined to be a viable method for experimental measurement of process window data. As long as accurate assumptions can be made about the optical performance of such projection tools, the response of photoresist to the delivered image can be studied experimentally using the demodulated interferometric imaging approach