This study presents an implantable microcontroller-based bi-directional transmission system with an inductive link designed for biological signal sensing. The system comprises an external module and an implantable module. The external module incorporates a high-efficiency class-E transceiver with amplitude modulation scheme and a data recovery reader. The transceiver sends both power and commands to the implanted module, while the reader recovers the recorded biological signal data and transmits the data to a personal computer (PC) for further data processing. To reduce the effects of interference induced by the 2 MHz carrier signal, the implanted module uses two separate coils to perform the necessary two-way data transmission. The outward backward telemetry circuitry of the implanted module was based on the loadshift keying (LSK) technique. The transmitted sensed signal had a 10-bit resolution and a read-out rate of 115 kbps. The implanted module, measuring 4.5 x 3 x 1.2 cm3, was successfully verified in animal experiment in which the electroneurogram (ENG) signal was recorded from the sciatic nerve of New Zealand rabbits in response to nociceptive stimulation of foot. The reliable operating distance of the system was within about 3.5 cm with an efficiency of around 25%. Our present study confirms that the proposed biological signal sensing device is suitable for various implanted applications following an appropriate biocompatible packaging procedure.

In this work, we established the relationship between the thermally induced microstructure development and the photoluminescence efficiency (E p ) of the poly(9,9-dioctylfluorene) (PF8) fibers prepared from the semidilute PF8/chloroform solutions by direct electrospinning. The as-spun (AS) fibers were found to be composed of an amorphous phase and a significant fraction of mesomorphic β-phase, which may promote the E p of PF8. The temperature-dependent wide-angle X-ray scattering (WAXS) measurement revealed that the PF8 fibers exhibited complex structural transformation on heating from the AS state, and there existed a strong correlation between E p and the microstructure developed. The AS fibers exhibited the highest E p value. The E p decreased progressively on heating at temperatures below the cold crystallization temperature (T cc ), where the microstructure remained unperturbed. The β-phase transformed to γor α′-phase (C γ -/C α′ -crystals) above T cc , and such a structural transformation led to a reduction of E p . With further heating, the C γ -/C α′ -crystals transformed into the more stable C α -crystals, presumably as the premelting−reorganization−remelting proceeded at the temperatures over the crystal transformation temperature (T ct ). The crystal transformation process reduced the E p markedly. Finally, above the melting temperature (T m ), the C α -crystals were disrupted into the disordered molten state, and the E p value remained largely unchanged up to 200 °C.

The effects of two different fluxes (A6 and B6) on the wetting performance of Sn-3.5Ag-0.5Cu lead-free solder balls were investigated during the reflow process. Solder ball wetting behavior in real time via an optical microscope coupled with a video recorder during the reflow process was studied. The leadfree solder balls started to melt and wet at 210°C by using A6, which is 8°C lower than the melting point (218°C) of the solder material used. The wetting performance of the lead-free solder ball was dramatically enhanced by using A6. The wettability test indicated that the height of the solder ball after the reflow process with flux A6 was significantly lower than that with B6. It was found that strong fluxing capability caused these phenomena.

ABSTACTIn this paper, a study on the relationship between W cured die-attach film (UVDAF) characterizes, process design, and the failure mechanism of reliability test were reported. The novelty films were a multifunctional tape, which consists of the function for dicing tape and die bonding tape. It focused on investigation of the behavior under the JEDEC level 3 precondition conditions, pressure cook test (PCT) and thermal cycle test (TCT). Besides, the paper discusses the thermal history effect on the chemical stability of UVDAF for the reliability issue. For instance, initial crosslinkage temperature of UVDAF affect on effectually contact area aller the die-mount process. The cure kinetic and thermal resistances of the UVDAF were analyzed by Differential Scanning Calorimetry (DSC) and Thermo gravimetric Analysis (TGA). The delamination surfaces were analysis by Scanning Acoustic Tomograph (SAT), Cross-section were scanned by electronic microscopy (SEM) and Optical Microscope (OM).The thermo-deformation and pressure-induced flow behaviors of UVDAF were evaluated by both penetration mode in Thermal Mechanical Analyzers (TMA) and dynamic mode in rheology test, respectively. Furthermore, OM and SEM results revealed that the chemical stability of UVDAF in process, from die-mount to molding, affect the final effectually adhesive area that obviously influenced the quality of stack CSP reliability.

The U.S. Food and Drug Administration allows a maximum of 72 mg of caffeine per 12 oz. serving (6 mg/oz). Consuming 400 mg of caffeine 3 times daily for 7 days may develop sleep disruption effects. However, it is still very hard for people to estimate how much caffeine is intake daily. Moreover, (-)epigallocatechin gallate (EGCG) is studied a potent antioxidant that may have therapeutic properties for anti-aging and cancer. Conventionally, both caffeine and EGCG could be measured by the protocols of high performance liquid chromatography; however, high precision instruments are required. In this work, the caffeine and EGCG are used as the template molecules and imprinted into poly(ethylene-co-vinyl alcohol), EVAL, via solvent evaporation. The EVAL membrane is then used as the sensing element for electrochemical analysis after templates removal. From the cyclic voltammetry measurement of the caffeine, the peak oxidation potential is shifted from 0.36 to 0.46 V when the final concentration of caffeine is from 0.01 to 1 mg/mL, and the highest current density is about 0.18 microA/cm2. The caffeine and EGCG concentrations measured in three real samples are about 0.10-0.13 mg/mL and 0.49-1.74 mg/mL, respectively. This molecularly imprinted polymeric coated electrode is potential employed as a home-care system.