On the Controllable Soft-Templating Approach to Mesoporous Silicates

Ordered mesoporous materials in catalysis

/pdf/chemical-strategies-to-design-textured-materials-from-cb2un3cizv.pdf

Chemical strategies to design textured materials: from microporous and mesoporous oxides to nanonetworks and hierarchical structures.

This review is focused on describing state-of-the-art synthetic routes for the preparation of magnetic nanoparticles useful for biomedical applications. In addition to this topic, we have also described in some detail some of the possible applications of magnetic nanoparticles in the field of biomedicine with special emphasis on showing the benefits of using nanoparticles. Finally, we have addressed some relevant findings on the importance of having well-defined synthetic routes to produce materials not only with similar physical features but also with similar crystallochemical characteristics.

https://iopscience.iop.org/article/10.1088/0022-3727/36/13/202/pdf

The preparation of magnetic nanoparticles for applications in biomedicine

The preparation of magnetic nanoparticles for applications in biomedicine : Biomedical applications of magnetic nanoparticles

High resolution X-ray scattering studies of thin smectic C* (SC) samples prepared between solid plates coated with obliquely evaporated silicon monoxide to favor surface director orientation tilted out of the surface plane, reveal a local layer structure which is dependent on the evaporation directions on the plates. Samples with the evaporation directions antiparallel exhibit uniformly tilted layers. Those with parallel evaporation directions exhibit a zig-zag defect free chevron structure of tilted layers.

Layer and director structure in surface stabilized ferroelectric liquid crystal cells with non-planar boundary conditions

X-ray scattering studies on a homologous series of thermotropic liquid crystals with one tail perfluorinated reveal that the smectic layer thickness depends only on the length of the fluorocarbon tail. Density measurements in combination with the x-ray results show that the average cross-sectional area per molecule, parallel to the smectic layers, depends only on the length of the hydrocarbon tail. These experimental results lead to a model in which steric interactions drive antiparallel alignment of nearest neighbors in the smectic-{ital A} and -{ital C} phases. These unique dimerlike phases have a layer spacing comparable to the length of the molecules, demonstrate registration of nearest neighbors along their lengths, and exhibit ferroelectric switching in the chiral smectic-{ital C} phase.

Dimerlike smectic-A and -C phases in highly fluorinated thermotropic liquid crystals.

The University of New Mexico/Sandia National Laboratories small-angle scattering laboratory provides a wide q-range, 3×10−4 A−1<q<0.7 A−1, for the structural analysis of materials on length scales from a few angstrom to ∼0.1 μm. The wide q-range is accomplished by combining data from a Bonse-Hart spectrometer (3×10−4 A−1<q<3×10−2 A−1) and a 5 m pinhole (3×10−3 A−1<q<0.7 A−1) instrument. Automation of the data acquisition systems along with a variety of sample environments and sample changers yields flexible, high throughput instruments.

The University of New Mexico/Sandia National Laboratories small-angle scattering laboratory

Heat transfer and combustion properties of a high explosive (HE) are influenced by the HE microstructure. The development of voids and cracks in an HE system under the conditions of thermal loading can have a strong impact on the safety and reliability of a weapon system. The optical microscopy and small‐angle x‐ray scattering (SAXS) techniques are useful tools for microstructural characterization. A combination of the tools allows lengthscales from hundreds of microns to tenths of nanometers to be probed, allowing a thorough description of a system’s microstructure to be made. We present an optical microscopy and SAXS study of the effects of thermal loading on the microstructure of PBX 9501. Pressed pellets of PBX 9501, an HMX‐based system, were heated in an oven at 180 °C for periods of 0, 15 and 30 minutes. Optical micrographs reveal the development of large pores in the microstructure with increasing thermal treatment as well as increased cracking and morphological changes of crystal grains, associate...

/pdf/an-optical-microscopy-and-small-angle-scattering-study-of-301cxv5p6w.pdf

An Optical Microscopy and Small‐Angle Scattering Study of Porosity in Thermally Treated PBX 9501

Heat transfer and comlmstion properties of a high explosive (HE) are influenced by the HE microstructure. The development of voids and cracks in an HE system under the conditions of thermal loading can have a strong impact on the safety and reliability of a weapon system. The optical microscopy and small angle x-ray scattering (SAXS) techniques are useful tools for microstructural characterization. A combination of the tools allows lengthscales from hundreds of microns to tenths of nanometers to be probed, allowing a thorough description of a system's microstructure to be made. We present an optical microscopy and SAXS study of the effects of thermal loading on the microstructure of PBX 9501. Pressed pellets of PBX 9501, an HMX-based system, were heated in an oven at 180 'C for periods of 0, 15 and 30 minutes. Optical micrographs reveal the developmenit of large pores in the microstructure with increasing thermal treatment as well as increased cracking and morphological changes of crystal grains, associated with the beta to delta phase transition in HMX. SAXS measurements were performed in order to quantify the observed porosity,

T. P. Rieker

Papers

Layer and director structure in surface stabilized ferroelectric liquid crystal cells with non-planar boundary conditions

Dimerlike smectic-A and -C phases in highly fluorinated thermotropic liquid crystals.

The University of New Mexico/Sandia National Laboratories small-angle scattering laboratory

An Optical Microscopy and Small‐Angle Scattering Study of Porosity in Thermally Treated PBX 9501

An Optical Microscopy and Small-Angle Scattering Study of Porosity in Thermally Treated PBX 9501