The Scale for Existential Thinking

This study introduced the construct of existential thinking, which we defined as the tendency to explore the fundamental concerns of human existence and the capacity to engage in a meaning-making process that locates oneself in respect to these issues. We also assessed the psychometric properties of the 11-item “Scale for Existential Thinking” (SET). In two studies, we found the SET to have unidimensional factor structure and good reliability diagnostics in both student and adult samples. Moreover, the SET showed construct validity by correlating with meaning in life, curiosity, and other existential variables. Furthermore, we found meaning in life to mediate the relation of existential thinking and existential wellbeing, which supports our conceptualization of existential thinking as a meaning-making process

G-133: A soft x ray solar telescope

The GOLDHELOX Project, NASA payload number G-133, is a robotic soft x ray solar telescope designed and built by an organization of undergraduate students. The telescope is designed to observe the sun at a wavelength of 171 to 181 A. Since we require observations free from atmospheric interference, the telescope will be launched in a NASA Get-Away-Special (GAS) canister with a Motorized Door Assembly (MDA). In this paper we primarily discuss the most important elements of the telescope itself. We also elaborate on some of the technical difficulties associated with doing good science in space on a small budget (about $100,000) and mention ways in which controlling the instrument environment has reduced the complexity of the system and thus saved us money

Base Dependent DNA-carbon Nanotube Interactions: Activation Enthalpies and Assembly-disassembly Control

We quantify the base dependent interactions between single stranded DNA and single walled carbon nanotubes (SWNTs) in solution. DNA/SWNT hybrids hold the promise of applications ranging from nanoscale electronics and assembly of nanotube based materials, to drug delivery and DNA sequencing. These applications require control over the hybrid assembly and disassembly. Our analytical assay reveals the order of nucleobase binding strengths with SWNTs as G>C>A>T. Furthermore, time dependent fixed temperature experiments that probe the kinetics of the dissociation process provide values for the equilibrium constants and dissociation enthalpies that underlie the microscopic interactions. Quantifying the base dependency of hybrid stability shows how insight into the energetics of the component interactions facilitates control over hybrid assembly and disassembly.Engineering and Applied SciencesMolecular and Cellular BiologyPhysic

Nanopatterning on Nonplanar and Fragile Substrates with Ice Resists

Electron beam (e-beam) lithography using polymer resists is an important technology that provides the spatial resolution needed for nanodevice fabrication. But it is often desirable to pattern nonplanar structures on which polymeric resists cannot be reliably applied. Furthermore, fragile substrates, such as free-standing nanotubes or thin films, cannot tolerate the vigorous mechanical scrubbing procedures required to remove all residual traces of the polymer resist. Here we demonstrate several examples where e-beam lithography using an amorphous ice resist eliminates both of these difficulties and enables the fabrication of unique nanoscale device structures in a process we call ice lithography. We demonstrate the fabrication of micro- and nanostructures on the tip of atomic force microscope probes, microcantilevers, transmission electron microscopy grids, and suspended single-walled carbon nanotubes. Our results show that by using amorphous water ice as an e-beam resist, a new generation of nanodevice structures can be fabricated on nonplanar or fragile substrates.Engineering and Applied SciencesMolecular and Cellular BiologyPhysic

Giant spontaneous magnetostriction in MnTe driven by a novel magnetostructural coupling mechanism

We present a comprehensive x-ray scattering study of spontaneous magnetostriction in hexagonal MnTe, an antiferromagnetic semiconductor with a Neel temperature of $T_{\mathrm{N}} = 307$ K. We observe the largest spontaneous magnetovolume effect known for an antiferromagnet, reaching a volume contraction of $|\Delta V/V| > 7 \times 10^{-3}$. This can be justified semiquantitatively by considering bulk material properties, the spatial dependence of the superexchange interaction, and the geometrical arrangement of magnetic moments in MnTe. The highly unusual linear scaling of the magnetovolume effect with the short-range magnetic correlations, beginning in the paramagnetic state well above $T_{\mathrm{N}}$, points to a novel physical mechanism, which we explain in terms of a trilinear coupling of the elastic strain with superposed distinct domains of the antiferromagnetic order parameter. This novel mechanism for coupling lattice strain to robust short-range magnetic order casts new light on magnetostrictive phenomena and also provides a template by which the exceptional magnetostrictive properties of MnTe might be realized in a wide range of other functional materials.Comment: Submitted May 11, 202

Ice Lithography for Nano-Devices

We report the successful application of a new approach, ice lithography (IL), to fabricate nanoscale devices. The entire IL process takes place inside a modified scanning electron microscope (SEM), where a vapor-deposited film of water ice serves as a resist for e-beam lithography, greatly simplifying and streamlining device fabrication. We show that labile nanostructures such as carbon nanotubes can be safely imaged in an SEM when coated in ice. The ice film is patterned at high e-beam intensity and serves as a mask for lift-off without the device degradation and contamination associated with e-beam imaging and polymer resist residues. We demonstrate the IL preparation of carbon nanotubes field effect transistors (FETs) with high quality trans-conductance properties.Engineering and Applied SciencesMolecular and Cellular BiologyPhysic

Ion Beam Nanosculpting and Materials Science with Single Nanopores

Work is reported in these areas: Nanopore studies; Ion sculpting of metals; High energy ion sculpting; Metrology of nanopores with single wall carbon nanotube probes; Capturing molecules in a nanopore; Strand separation in a nanopore; and DNA molecules and configurations in solid-state nanopores

Embedding a Carbon Nanotube across the Diameter of a Solid State Nanopore

A fabrication method for positioning and embedding a single-walled carbon nanotube (SWNT) across the diameter of a solid state nanopore is presented. Chemical vapor deposition (CVD) is used to grow SWNTs over arrays of focused ion beam (FIB) milled pores in a thin silicon nitride membrane. This typically yields at least one pore whose diameter is centrally crossed by a SWNT. The final diameter of the FIB pore is adjusted to create a nanopore of any desired diameter by atomic layer deposition, simultaneously embedding and insulating the SWNT everywhere but in the region that crosses the diameter of the final nanopore, where it remains pristine and bare. This nanotube-articulated nanopore is an important step towards the realization of a new type of detector for biomolecule sensing and electronic characterization, including DNA sequencing.Engineering and Applied SciencesMolecular and Cellular BiologyPhysic