Abstract: A hydrogel composition is provided. The hydrogel composition includes polyglutamic acid (PGA) containing maleimide groups, and polyethylene glycol (PEG) containing terminal thiol groups, wherein the hydrogel composition has a pH value ranging from 4.0 to 6.5. A drug delivery system is also provided. The drug delivery system includes the above-mentioned hydrogel composition, and a pharmaceutically active ingredient encapsulated in the hydrogel composition.

Abstract: A pH-responsive nanoparticle made of a pH-responsive polymer and a poly(lactic-co-glycolic acid) by self-assembly includes a polyethylene glycol derivative and a R-Histidine derivative that are subjected to a chemical reaction to form the pH-responsive polymer, wherein the surface electric potential of the pH-responsive nanoparticle is ?25 to 10 mV, such that when a pH value of the pH-responsive nanoparticle is changed from 7.4 to 5.0 depending upon an external environment, a surface zeta potential of the pH-responsive nanoparticle is converted from negative charge to positive charge.

Abstract: A hydrogel composition is provided. The hydrogel composition includes polyglutamic acid (PGA) containing maleimide groups, and polyethylene glycol (PEG) containing terminal thiol groups, wherein the hydrogel composition has a pH value ranging from 4.0 to 6.5. A drug delivery system is also provided. The drug delivery system includes the above-mentioned hydrogel composition, and a pharmaceutically active ingredient encapsulated in the hydrogel composition.

Abstract: A pH-responsive nanoparticle made of a pH-responsive polymer and a poly(lactic-co-glycolic acid) by self-assembly includes a polyethylene glycol derivative and a R-Histidine derivative that are subjected to a chemical reaction to form the pH-responsive polymer, wherein the surface electric potential of the pH-responsive nanoparticle is ?25 to 10 mV, such that when a pH value of the pH-responsive nanoparticle is changed from 7.4 to 5.0 depending upon an external environment, a surface zeta potential of the pH-responsive nanoparticle is converted from negative charge to positive charge.

Abstract: A multi-stage magnetic switch includes a base and a rotary member rotatably held in the base. The base holds a latch member elastically extended outwards. The rotary member includes a plurality of latch notches. Each latch notch has a latch plane and an arched convex surface which have respectively one side extended to the outer surface of the rotary member. The latch member latches on the latch plane and is adjacent to the arched convex surface. The latch member is pressed and retracted through the latch plane when the rotary member rotates against the base so that the latch member latches on the latch notches sequentially to form multi-stage positioning. Moreover, greater force can be applied to retract the latch member pressed by the arched convex surface to reverse the rotary member. The switch of the invention thus formed has simple structure and makes multi-stage positioning easier.

Abstract: A fast anchoring magnetic holder including multiple attractive surfaces comprises a first magnet, a second magnet, a first insertion rod and a second insertion rod. The first magnet has a magnetic workstation surface. The second magnet has a magnetic anchor surface. The first and second magnets are stacked together. The first insertion rod and second insertion rod are respectively inserted into the first magnet and second magnet, and are turned to change distribution of the magnetic field of the first magnet and second magnet to alter the magnetic workstation surface and magnetic anchor surface from a non-magnetic state to a magnetic state to attract a working piece to a workstation.

Abstract: A multi-stage positioning rotary disk includes an inner disk and an outer disk hinged on the inner disk and turnable thereon. The inner disk has at least one latch cavity to hold a latch member elastically extended outwards from the latch cavity. The outer disk has a plurality of positioning slots latched with the latch member. Each positioning slot is formed from a greater depth to a smaller depth according to turning direction of the outer disk. Hence the latch member is latched sequentially on the positioning slots during relative turning between the outer disk and inner disk to allow the outer disk to provide staged positioning function. The structure is simpler and staged positioning is easy to operate when in use, and durability is enhanced and production cost is lower.

Abstract: A fast anchoring magnetic holder including multiple attractive surfaces comprises a first magnet, a second magnet, a first insertion rod and a second insertion rod. The first magnet has a magnetic workstation surface. The second magnet has a magnetic anchor surface. The first and second magnets are stacked together. The first insertion rod and second insertion rod are respectively inserted into the first magnet and second magnet, and are turned to change distribution of the magnetic field of the first magnet and second magnet to alter the magnetic workstation surface and magnetic anchor surface from a non-magnetic state to a magnetic state to attract a working piece to a workstation.

Abstract: A magnetic vise comprises a holder, a movable portion, a rotary bar and a magnetic portion. The magnetic portion is located beneath the holder. The holder has a butting surface extended transversely and a boss opposing the butting surface. The rotary bar is a turnable screw bar running through the boss and has a distal end latched on the movable portion to push and pull the movable portion. The movable portion has a clamping surface facing the butting surface. A working piece can be positioned on the holder and attracted by the magnetic force of the magnetic portion to be tightly attached to the holder. The rotary bar can be turned to drive the movable portion against the holder so that the clamping surface is moved towards the butting surface to clamp the working piece without skewing during the clamping process.

Abstract: A switch type ON/OFF structure for hoisting magnetic disks has a handle turnable towards one side to demagnetize and towards another side to generate a magnetic force to attract and move a work piece. The handle is hinged on one end surface of a hoisting magnetic disk which also has a first detent member and a second detent member. The first and second detent members can stop the turning of the handle. The handle further has an extensible latch member at one side spaced from the handle at a selected interval. The latch member has a distal end slidable over the second detent member and extendable downwards to allow the second detent member to be wedged in the interval and anchored. Thereby the hoisting magnetic disk can provide the magnetic attracting force and hoist and move the work piece safer.

Abstract: A switch type ON/OFF structure for hoisting magnetic disks has a handle turnable towards one side to demagnetize and towards another side to generate a magnetic force to attract and move a work piece. The handle is hinged on one end surface of a hoisting magnetic disk which also has a first detent member and a second detent member. The first and second detent members can stop the turning of the handle. The handle further has an extensible latch member at one side spaced from the handle at a selected interval. The latch member has a distal end slidable over the second detent member and extendable downwards to allow the second detent member to be wedged in the interval and anchored. Thereby the hoisting magnetic disk can provide the magnetic attracting force and hoist and move the work piece safer.

Abstract: An improved electromagnetic chuck which does not require a continuous direct current supply while being magnetized, including a main body defining a plurality of recesses and forming a cover, which includes a plurality of magnetically conductive portions and non-magnetically conductive portions alternately arranged, a plurality of magnetic units arranged within said plurality of recesses, and a magnetizing/demagnetizing circuit for magnetizing/demagnetizing said plurality of magnetic units, is provided. The magnetizing/demagnetizing circuit includes a magnetizing circuit, a demagnetizing circuit and an output circuit, by which a direct current is generated to magnetize the electromagnetic chuck, or a pair of positive and negative phase pulses with a gradually increased frequency is generated to quickly demagnetize the electromagnetic chuck.