All-optical vector cesium magnetometer

Based on power modulation of a pump laser and precessional projection detection, we present an all-optical vector magnetometer of cesium, which has a demonstrated magnitude sensitivity of 80 fT/Hz 1/2 and an orientation sensitivity of 0.1°/Hz 1/2. In the device, four main factors are measured experimentally, which are the Larmor precession frequency of a polarized magnetic moment that depends on the modulus of the measured magnetic field only, two phase shifts and amplitude ratio of the precession projection in the two probe directions relative to the magnetic field orientation. This kind of magnetometer with high sensitivity in the range of the spatial angle is suitable for solving the inverse problem and geomagnetic navigation

Bis[μ-2-(2-naphth­oxy)acetato]bis­{aqua[2-(2-naphth­oxy)acetato]zinc(II)}

The title binuclear ZnII compound, [Zn2(C12H9O3)4(H2O)2], is centrosymmetric. Each Zn atom is coordinated by two bridging 2-naphthoxyacetate anions, one terminal 2-naphth­oxy­acetate anion and one water mol­ecule in a distorted ZnO4 tetra­hedral geometry. The naphthalene system of the bridging ligand is nearly perpendicular to the naphthalene of the terminal ligand, with a dihedral angle of 78.26 (6)°. Within the binuclear mol­ecule the Zn⋯Zn separation is 3.815 (5) Å. In the crystal structure, inter­molecular O—H⋯O hydrogen bonding between the water mol­ecule and carboxyl­ate groups helps to stabilize the crystal structure

Rear-Surface Collapse of Finite Thickness Concrete Targets under Internal Explosion

An experimental investigation on the buried internal explosion in finite thickness concrete targets was carried out, with the aim at developing an available criterion for the critical collapse of rear-surface to determine the critical collapse thickness and the critical amount of explosive charge under different depth of buried. It is found, under a certain density and diameter of explosive charge, the critical collapse thickness increases monotonically with the length-to-diameter ratio or the amount of the explosive charge, but the increasing becomes slower down after the length-to-diameter ratio of the explosive charge is larger than about 5, which implies that the geometry of the explosive charge can have much influence on the damage and failure of concrete targets due to different mechanism of energy dissipation. Moreover, by using the dimensional analysis approach, the function relation between the dimensionless critical collapse thickness and the length-to-diameter ratio was obtained, which shows that the dimensionless critical collapse thickness depends on both the amount and the length-to-diameter ratio of the charge.Defence Science Journal, 2012, 62(5), pp.295-299, DOI:http://dx.doi.org/10.14429/dsj.62.123

7-Benzyl-3-(4-fluoro­phen­yl)-2-propyl­amino-5,6,7,8-tetra­hydro­pyrido[4′,3′:4,5]thieno[2,3-d]pyrimidin-4(3H)-one

In the title compound, C25H25FN4OS, the thienopyrimidine fused-ring system is close to planar (r.m.s. deviation = 0.0089 Å), with a maximum deviation of 0.0261 (17) Å for the N atom adjacent to the benzene ring. This thienopyrimidine fused-ring system forms dihedral angles of 64.73 (3) and 81.56 (5)° with the adjacent benzyl and fluoro­phenyl rings, respectively. Inter­molecular N—H⋯F and C—H⋯F hydrogen bonding, as well as C—F⋯π inter­actions [F⋯centroid = 3.449 (3) Å; C—F⋯centroid = 91.87 (15)°], help to stabilize the crystal structure