Abstract: An inkjet pen including an ink reservoir for storing ink and providing ink for jetting. A port, located on top of the ink reservoir, fluid-communicated with the ambient air, is used for adjusting the air pressure inside the reservoir. A valve, operated by a spring or a resilient element, normally seals the port, while occasionally opening the port to introduce air into the reservoir when the ink level is low and the underpressure rises. In other embodiments, an elastic bag is included in the reservoir that has an opening communicated with the ambient air through a second port formed on top of the reservoir. The elastic bag expands in response to the increasing underpressure generated in the reservoir when ink is being used. The bag expansion actuates the opening of the valve so as to regulate the underpressure.

Abstract: A gene gun is described wherein the contour design of the spray nozzle of the gene gun modifies the operation of the gene gun. A low pressure gas is used to accelerate the micro-particles that are coated with nucleic acid of a foreign gene into cytoplasma or nuclei of an animal or plant cell to express the special protein and to generate the new biological function.

Abstract: An improved nursing bottle has two opened ends, equipped with an air-penetrating board, a discharge regulating element in funnel shape, and a pair of lower and upper caps. The air-penetrating board, secured to the bottom of the bottle by a removably attached cap, is fabricated with a number of air-inlet apertures thereon, which permit air to flow in therethrough as long as the nipple is sucked by the infant using the bottle, producing an unbalanced air pressure therein so as to get the closed aperture open for allowing air to flow in so to make the fluid discharge in a more steady manner. Also, air bubbles, which often cause infants using nursing bottles to cough, can not form therein, and the problem of swallowing a lot of air in feeding by the infant can also be prevented. Furthermore, this kind of bottle can be cleaned with much ease.