Digitally Controlled Oscillator with High Timing Resolution and Low Complexity for Clock Generation.

This paper presents a digitally controlled oscillator (DCO) with a low-complexity circuit structure that combines multiple delay circuits to achieve a high timing resolution and wide output frequency range simultaneously while also significantly reducing the overall power consumption. A 0.18 µm complementary metal-oxide-semiconductor standard process was used for the design, and measurements showed that the chip had a minimum controllable timing resolution of 4.

Extracellular and intracellular intermittent magnetic-fluid hyperthermia treatment of SK-Hep1 hepatocellular carcinoma cells based on magnetic nanoparticles coated with polystyrene sulfonic acid.

The use of magnetic nanoparticles (MNPs) magnetized on applying an alternating magnetic field (AMF) to stimulate the thermal characteristics and to induce tumor apoptosis is a currently active area of research in cancer treatment. In previous work, we developed biocompatible and superparamagnetic polystyrene-sulfonic-acid-coated magnetic nanoparticles (PSS-MNPs) as applications for magnetically labeled cell trapping, but without assessment of treatment effects on tumor diseases. In the present work, we examined PSS-MNP-induced magnetic fluid hyperthermia (MFH) on SK-Hep1 hepatocellular carcinoma (HCC) cells for lethal thermal effects with a self-made AMF system; an adjustable AMF frequency generated a variable intensity of magnetic field and induced MNP relaxation.

Thermoelectric Effects of Nanogaps between Two Tips.

This study designs a microscaled thermoelectric component featuring a nanogap of varying size (133-900 nm) between the tips of the component. Electricity and heat are transmitted between the gap of the tips through the thermionic emission of electrons. Because the gaps exhibit a discontinuous structure, the phonon's contribution to thermal conductivity can be virtually neglected, thereby enhancing the thermoelectric figure of merit (ZT) of the designed thermoelectric component.

Influence of magnetic domain walls and magnetic field on the thermal conductivity of magnetic nanowires.

We investigated the influence of magnetic domain walls and magnetic fields on the thermal conductivity of suspended magnetic nanowires. The thermal conductivity of the nanowires was obtained using steady-state Joule heating to measure the change in resistance caused by spontaneous heating. The results showed that the thermal conductivity coefficients of straight and wavy magnetic nanowires decreased with an increase in the magnetic domain wall number, implying that the scattering between magnons and domain walls hindered the heat transport process.

Wheatstone bridge giant-magnetoresistance based cell counter.

A Wheatstone bridge giant magnetoresistance (GMR) biosensor was proposed here for the detection and counting of magnetic cells. The biosensor was made of a top-pinned spin-valve layer structure, and it was integrated with a microchannel possessing the function of hydrodynamic focusing that allowed the cells to flow in series one by one and ensured the accuracy of detection. Through measuring the magnetoresistance variation caused by the stray field of the magnetic cells that flowed through the microchannel above the GMR biosensor, we can not only detect and count the cells but we can also recognize cells with different magnetic moments.

Single cell detection using 3D magnetic rolled-up structures.

A 3D rolled-up structure made of a SiO2 layer and a fishbone-like magnetic thin film was proposed here as a biosensor. The magnetoresistance (MR) measurement results of the sensor suggest that the presence of the stray field, which is induced by the magnetic nanoparticles, significantly increased the switching field. Comparing the performance of the 2D sensor and 3D sensor designed in this study, the response in switching field variation was 12.

Single cell detection using a magnetic zigzag nanowire biosensor.

A magnetic zigzag nanowire device was designed for single cell biosensing. Nanowires with widths of 150, 300, 500, and 800 nm were fabricated on silicon trenches by electron beam lithography, electron beam evaporation, and lift-off processes. Magnetoresistance measurements were performed before and after the attachment of a single magnetic cell to the nanowires to characterize the magnetic signal change due to the influence of the magnetic cell.

Magnetically-controllable zigzag structures as cell microgripper.

We designed and fabricated a micro-scaled cell gripper based on two highly flexible magnetic zigzag structures that can be actuated by a magnetic field. Elongated single domain magnetic thin films with high magnetic shape anisotropy were deposited on the zigzag structures. By adjusting the external magnetic field we were able to control the torque applied on the magnetic films that was responsible for the actuation.