PMC

An alligator forceps was inserted into an ST-E tube alongside a gastroscope and, under the guidance of gastroscopy, the stent wire was gripped and pulled up into the ST-E tube. Biopsy forceps were inserted into the lower section of the Z-shaped stent through a biopsy hole in the gastroscope to fix the stent; in the meantime, the alligator forceps continued to be used to pull up the stent wire until the Z-shaped metal loops became elongated strips. All the stent wire was removed in stages through the ST-E tube.

Schematic of (a) Z-shaped path; (b) vertical path; and (c) contour filling path. (d–f) mean three kinds of layer-to-layer overlapping methods.

Macro images of samples 5, 6, and 7 with different tool paths: (a) Z-shaped path; (b) vertical path; and (c) contour-filling path.

(a) The current ratio between a central Z-shaped wire and two U-shaped control wires allows us to precisely tune the trap geometry. For a symmetric current flow, the trap minimum is positioned below the center of the Z-wire, with the long trap axis aligned to the horizontal direction. (b) 2d cut through the trapping potentials for and (c) at a constant external Bias field of , respectively. (d,e) Cuts through the radial trap minimum of the same potentials to show the axial trap deformation.