Work of fracture of sodium chloride single crystals

A mathematical analysis of the stress field of dislocations in a slip plane was applied to explain the optical birefringence in sodium chloride during plastic deformation. This high birefringence of slip planes accompanying plastic deformation, without appreciable isoclinic or isochromatic birefringence, makes it possible to study the plastic zone at the crack tip and the mechanisms of fracture. Three-point bending at a slow test speed was used to calculate the work of fracture (W(,wof)), the crack driving force (G), the crack propagation resistance (R), and the plastic energy dissipation rate ((phi)(,p)). The work of fracture and first maximum load are suggested as parameters suitable to indicate the occurrence of brittle to ductile transition

N′-(2-Hydr­oxy-5-chloro­benzyl­idene)-4-nitro­benzohydrazide methanol solvate

The title compound, C14H10ClN3O4·CH4O, was synthesized from the reaction of 5-chloro­salicylaldehyde with 4-nitro­benzohydrazide in methanol. The Schiff base mol­ecule is nearly planar, with a dihedral angle of 9.1 (3)° between the two benzene rings. The methanol solvent mol­ecules are linked to the Schiff base mol­ecules by N—H⋯O, O—H⋯N and O—H⋯O hydrogen bonds, forming chains running parallel to the a axis

Differential vascular cell adhesion molecule-1 expression and superoxide production in simulated microgravity rat vasculature

Exposure to microgravity leads to orthostatic intolerance in astronauts and differential vascular structural and functional adaptations have been implicated in its occurrence. The present study tended to clarify the characteristics of vascular inflammation and oxidative stress in hindlimb unweighting (HU) rat vasculature. Male Sprague-Dawley rats were randomly divided into control (CON) and hindlimb unweighting (HU) groups. Three weeks later, immunohistochemistry was used to localize the expression of vascular cell adhesion molecule-1 (VCAM-1) and laser scanning confocal microscope were used to detect superoxide production. Immunohistochemical results revealed positive staining of VCAM-1 on endothelial cells in HU rat basilar and carotid arteries compared with CON, but not in abdominal aorta and femoral arteries. Meanwhile, HU increased O2·- levels in all the layers of basilar and carotid arteries from HU rat but not in abdominal aorta and femoral arteries from HU rat. These data suggested that differential expression of VCAM-1 and O2- production were concomitant with the vascular adaptations to simulated microgravity and whether they participate in vascular structure and function remodeling merits further investigation

The Ginger-shaped Asteroid 4179 Toutatis: New Observations from a Successful Flyby of Chang'e-2

On 13 December 2012, Chang'e-2 conducted a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 $\pm$ 120 meters from the asteroid's surface. The highest-resolution image, with a resolution of better than 3 meters, reveals new discoveries on the asteroid, e.g., a giant basin at the big end, a sharply perpendicular silhouette near the neck region, and direct evidence of boulders and regolith, which suggests that Toutatis may bear a rubble-pile structure. Toutatis' maximum physical length and width are (4.75 $\times$ 1.95 km) $\pm$10$\%$, respectively, and the direction of the +$z$ axis is estimated to be (250$\pm$5$^\circ$, 63$\pm$5$^\circ$) with respect to the J2000 ecliptic coordinate system. The bifurcated configuration is indicative of a contact binary origin for Toutatis, which is composed of two lobes (head and body). Chang'e-2 observations have significantly improved our understanding of the characteristics, formation, and evolution of asteroids in general.Comment: 21 pages, 3 figures, 1 tabl

Spatial Variability and Site-Specific Nutrient Management in a Vegetable Production Area

Soil nutrients showed similar spatial distribution patterns across the study site in Hebei Province and were correlated with vegetable production history and fertilizer application rates. Vegetable crop type and history of fertilizer use were important factors in the development of a regional nutrient management program. NorthceNtral chiNa Abbreviations and notes for this article: N = nitrogen; P = phosphorus; K = potassium; S = sulfur; Ca = calcium; Mg = magnesium; Zn = zinc; Cu = copper; Fe = iron; Mn = manganese; B = boron; NO 3 --N = nitrate-N; NH 4 + = ammonium; GPS = global positioning system; GIS = geographic information system; OM = organic matter; SSNM = site-specific nutrient management; CV = coefficient of variation; FP = farm practice