The development of ultrafast gas electron diffraction with nonrelativistic electrons has enabled the determination of molecular structures with atomic spatial resolution. It has, however, been ...challenging to break the picosecond temporal resolution barrier and achieve the goal that has long been envisioned—making space- and-time resolved molecular movies of chemical reaction in the gas-phase. Recently, an ultrafast electron diffraction (UED) apparatus using mega-electron-volt (MeV) electrons was developed at the SLAC National Accelerator Laboratory for imaging ultrafast structural dynamics of molecules in the gas phase. The SLAC gas-phase MeV UED has achieved 65 fs root mean square temporal resolution, 0.63 Å spatial resolution, and 0.22 Å−1 reciprocal-space resolution. Such high spatial-temporal resolution has enabled the capturing of real-time molecular movies of fundamental photochemical mechanisms, such as chemical bond breaking, ring opening, and a nuclear wave packet crossing a conical intersection. In this paper, the design that enables the high spatial-temporal resolution of the SLAC gas phase MeV UED is presented. The compact design of the differential pump section of the SLAC gas phase MeV UED realized five orders-of-magnitude vacuum isolation between the electron source and gas sample chamber. The spatial resolution, temporal resolution, and long-term stability of the apparatus are systematically characterized.
The conversion of light into usable chemical and mechanical energy is pivotal to several biological and chemical processes, many of which occur in solution. To understand the structure–function ...relationships mediating these processes, a technique with high spatial and temporal resolutions is required. Here, we report on the design and commissioning of a liquid-phase mega-electron-volt (MeV) ultrafast electron diffraction instrument for the study of structural dynamics in solution. Limitations posed by the shallow penetration depth of electrons and the resulting information loss due to multiple scattering and the technical challenge of delivering liquids to vacuum were overcome through the use of MeV electrons and a gas-accelerated thin liquid sheet jet. To demonstrate the capabilities of this instrument, the structure of water and its network were resolved up to the
3
rd hydration shell with a spatial resolution of 0.6 Å; preliminary time-resolved experiments demonstrated a temporal resolution of 200 fs.
The Veterans Affairs mission to provide equitable, accessible, and patient-centered care necessitates that culturally appropriate interventions are available when cultural differences may jeopardize ...engagement in care. However, within the VA, wounded warriors residing in rural areas in the Pacific Islands have been offered interventions that were developed and tested using largely urban mainland populations. The objectives of this article were to (a) document the cultural adaptation of a cognitive-behavioral clinical intervention for use by rural Pacific Island veterans, and (b) report feasibility data for the intervention. The 5-stage Map of the Adaptation Process (assessment, selection, preparation, piloting, and refinement) was used to structure the work. The resultant intervention, called "Koa," is a multisession family psychoeducational program that integrates selected Pacific Islander values, beliefs, and healing traditions with an empirically based mainstream U.S. intervention. To pilot Koa, rural Pacific Island dyads (28 veterans and 28 family members) participated via video teleconference and completed pre- and post- intervention measures. Outcome data indicated that participants perceived the intervention to be highly acceptable, useful, and relevant. Relationship quality scores substantially improved postintervention as measured by the Dyadic Relationship Scale (95% CI −10.97, −1.84, t(22) = −2.9, p = .008, d = −0.53 for veterans; 95% CI −11.06, −2.47, t(21) = −3.28, p = .004, d = −0.68 for family members). Family caregiving burden also improved significantly. The positive results of this investigation support the development of culturally adapted mental health interventions for culturally distinct subgroups of veterans and their families.
Niobium (Nb) Superconducting RF (SRF) cavities have been used or will be used for a number of particle accelerators. The fundamental limit of the accelerating gradient has been thought to be around ...50 MV/m due to its RF critical magnetic field of around 200 mT. This limit will prevent new projects requiring higher gradient and compact accelerators from considering SRF structures. There is a theory, however, that promises to overcome this limitation by coating thin (less than the penetration depth) superconductors on Nb. We initiated measurements of critical magnetic fields of Nb coated with various thin film superconductors, starting with MgB2 films deposited using reactive evaporation technique, with the goal to apply this coating to SRF cavities. This paper will present first test results of the RF critical magnetic field of a system consisting of a 10 nm B and a 100 nm MgB2 films deposited on a chemically polished 2-inch single grain Nb substrate.
Physicochemical changes of Japanese cockle foot parts occurring during cooking and cold storage at 4°C for 10 days were examined. Raw samples decreased in weight by 27% during cooking at 85°C for 15 ...s. Both raw and cooked samples decreased in weight to the same extent of 22–23% during the 10‐day cold storage. The levels of ATP and related compounds, as well as those of free amino acids, were higher in raw than in cooked samples, although the former were found by sensory evaluation to have a stronger fishy odor. Raw samples started to decrease in ATP content after 5 days of cold storage, showing K′ values of 18 and 42% after 5 and 7 days, respectively. The L* value in the Hunter scale color evaluation increased during the cold storage of raw samples, revealing a gradual disappearance of its original purple–gray color. Meanwhile, the L* value of cooked samples remained constant during the cold storage. The tensile strength of cooked samples was significantly higher than those of both raw samples before and after the cold storage, indicating increased toughness by cooking.
The development of ultrafast gas electron diffraction with non-relativistic electrons has enabled determination of molecular structures with atomic spatial resolution. It has, however, been ...challenging to break the picosecond temporal resolution barrier and achieve the goal that has long been envisioned – making space- and-time resolved molecular movies of chemical reaction in the gas-phase. Recently, an ultrafast electron diffraction (UED) apparatus using mega-electron-volt (MeV) electrons was developed at SLAC National Accelerator Laboratory for imaging ultrafast structural dynamics of molecules in the gas phase. The SLAC gas-phase MeV UED has achieved 70 fs root-mean-square temporal resolution, 0.63 Å spatial resolution, and 0.22 Å–1 reciprocal-space resolution. Such high spatial-temporal resolution has enabled the capturing of real-time molecular movies of fundamental photochemical mechanisms, such as chemical bond breaking, ring opening, and a nuclear wave packet crossing a conical intersection. In this paper, the design that enables the high spatial-temporal resolution of the SLAC gas phase MeV UED is presented. The compact design of the differential pump section of the SLAC gas phase MeV UED realized five orders-of-magnitude vacuum isolation between the electron source and gas sample chamber. The spatial resolution, temporal resolution and long-term stability of the apparatus are systematically characterized.
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