normal 0 false false false en-us x-none fa introduction: in radiation therapy centers across iran, protection of normal tissues is usually accomplished by either cerrobend or lead block shielding. in this study, the influence of these two shielding methods on central axis dose distribution of photon beam a cobalt unit was investigated in clinical conditions. materials and methods: all measureme...

The shield tunnel of the Kunming subway crosses beneath the Kun-Shi Railway. Due to the high requirements of railway track for settlement control, this article proposes the following technical measures for controlling the settlement based on the analysis of risks arising from the shield crossing railway: (1) Reinforcing the stratum of the region crossed by the shield in advance to achieve high ...

 Introduction: Nowadays, applications of free-lead radiation shields are increased specially for weighting factor and toxicity of lead elements. Although touching the lead may be results in the nervousand blood system of body, it is not exactly proven yet. Protective measures are the fundamental parts of radiation protection. On the other hand, high weighting factor of lead sh...

The Dalkon Shield was an intrauterine contraceptive device (IUD) that women used in the early 1970s and 1980s. Produced by the A.H. Robins Company in the US, the Dalkon Shield was a contraceptive device placed directly into a woman?s uterus [3] that was supposed to prevent pregnancy [4]. In the 1980s, researchers discovered that the Dalkon Shield caused an array of severe injuries, including pe...

Shield tunneling construction of metro infrastructure will continuously disturb the soils. The ground surface will be subjected to uplift or subsidence due to the deep excavation and the extrusion and consolidation of the soils. Implementation of the simultaneous monitoring with the shield tunnel construction will provide an effective reference in controlling the shield driving, while how to de...

Abstract Solid-state batteries (SSBs) are considered to be the next-generation lithium-ion battery technology due their enhanced energy density and safety. However, high electronic conductivity of solid-state electrolytes (SSEs) leads Li dendrite nucleation proliferation. Uneven electric-field distribution resulting from poor interfacial contact can further promote dendritic deposition lead rap...

The appearance of the embryonic shield, a slight thickening at the leading edge of the blastoderm during the formation of the germ ring, is one of the first signs of dorsoventral polarity in the zebrafish embryo. It has been proposed that the shield plays a role in fish embryo patterning similar to that attributed to the amphibian dorsal lip. In a recent study, we fate mapped many of the cells ...

Background: Prompt gamma neutron activation analysis (PGNAA) is known as a non-invasive technique capable of measuring elemental concentration in voluminous samples in a short period of time. Also it is a valuable diagnostic tool for total body elemental measurements. 252Cf and 241Am-Be sources which are usually used in this method, generate not only neutrons, but also emit high-energy and unwa...

We study the robustness of quantum information stored in the degenerate ground space of a local, frustration-free Hamiltonian with commuting terms on a 2D spin lattice. On one hand, a macroscopic energy barrier separating the distinct ground states under local transformations would protect the information from thermal fluctuations. On the other hand, local topological order would shield the gro...