We investigated the microstructural evolution of Sn96.4Ag2.8Cu0.8 solder through in situ heating transmission electron microscopy observations. As-soldered bump consisted of seven layers, containing the nanoeutectic lamella structure of AuSn and Au5Sn phases, and the polygonal grains of AuSn2 and AuSn4, on Au-plated Cu bond pads. Here, we found that there are two nanoeutectic lamellar layers with lamella spacing of 40 and 250 nm. By in situ heating above 140°C, the nanoeutectic lamella of AuSn and Au5Sn was decomposed with structural degradation by sphering and coarsening processes of the lamellar interface. At the third layer neighboring to the lamella layer, on the other hand, Au5Sn particles with a zig-zag shape in AuSn matrix became spherical and were finally dissipated in order to minimize the interface energy between two phases. In the other layers except both lamella layers, polycrystal grains of AuSn2 and AuSn4 grew by normal grain growth during in situ heating. The high interface energy of nanoeutectic lamella and polygonal nanograins, which are formed by rapid solidification, acted as a principal driving force on the microstructural change during the in situ heating.

The in vitro corrosion mechanism of the biodegradable cast Mg–10% Ca binary alloy in Hanks' solution was evaluated through transmission electron microscopy observations. The corrosion behavior depends strongly on the microstructural peculiarity of Mg2Ca phase surrounding the island-like primary Mg phase and the fast corrosion induced by the interdiffusion of O and Ca via the Mg2Ca phase of lamellar structure. At the corrosion front, we found that a nanosized crack-like pathway was formed along the interface between the Mg2Ca phase and the primary Mg phase. Through the crack-like pathway, O and Ca are atomically exchanged each other and then the corroded Mg2Ca phase was transformed to Mg oxides. The in vitro corrosion by the exchange of Ca and O at the nanosized pathway led to the rapid bulk corrosion in the Mg–Ca alloys.

Background: Agraphia in Korean patients may be different from agraphia in other patients who use alphabetical writing systems due to the “visuoconstructional script” characteristics of the Korean writing system, Hangul. Patients with early onset Alzheimer's disease (EOAD) have a severe degree of hypometabolism in the parietal area, which is known to be involved in processing visuospatial function. Thus, we explored the diverse error patterns manifested in writing single syllables in Korean patients with EOAD.

Methods: A study sample of 35 patients with EOAD and 18 healthy controls (HC) performed a Hangul writing task. We analyzed the erroneous responses of the subjects according to visuoconstructional and linguistic characteristics. In addition, we evaluated the relationship between Hangul writing and the neuropsychological variables as well as the severity of dementia.

Results: When comparing the total number of erroneous responses between EOAD and HC groups, the performances of EOAD patients were significantly worse than those of HC. EOAD patients demonstrated visuoconstructional errors even in the early stages of the disease. Severity of dementia and multiple cognitive domains such as attention, language, immediate memory, and frontal executive functions significantly correlated with the performance of Hangul writing.

Conclusion: Our findings suggest that patients with EOAD exhibit not only linguistic errors but also visuoconstructional manifestations of agraphia, which are associated with cognitive impairments in the multiple domains.

The triggered control of interfacial properties on the nanometer scale holds significant promise for actuation in bio-nanotechnology applications where polymeric actuators may manipulate the transport, separation, and detection of biomolecules. To fabricate patterned, stimulus-responsive polymer brushes we have developed several methods that combine surface initiated polymerization (SIP) with dip-pen nanolithography (DPN). Surface-confined, stimulus-responsive polymer brush nanopatterns were fabricated by amplification of DPN patterned, self-assembled monolayers of 16-mercaptohexadecanoic acid on gold surfaces by SIP of N-isopropylacrylamide (NIPAAm). While free radical polymerization yielded only short polymer brushes (DP<50), atom transfer free radical polymerization (ATRP) produced thick, uniform polymer brushes. For free radical polymerization the thickness of the polymer brush layer is a function of the lateral feature size and the initiator density and is maximal at pattern boundaries.

A plasma-enhanced chemical vapor deposition-based nitrogen-free dielectric anti-reflective coating was successfully developed for use in 90nm interconnects in conjunction with low κ materials. By choosing N-free precursors, it was possible to eliminate any adverse interactions between the NH2 amine group and the DUV 193nm photoresist that is directly in contact with the anti-reflective coating (ARC), thus eliminating major source of photoresist poisoning-induced footing. N-free dielectric ARC demonstrated a wide tunable range of its optical properties at 193nm in a single wafer PECVD reactor: 1.6<n<1.9 and 0< k<1.1. This range enables cost-effective and in-situ deposition of a dual-layer dielectric ARC on the low λ dielectric layers during the dual damascene process. The dual-layer coating, which consists of a phase-shift layer on an absorbing layer, can keep the substrate reflectivity below 1% across the wafer, minimizing CD swing. N-Free dielectric ARC can be easily integrated with low κ dielectrics. Its adhesion with low κ materials is excellent and it can be etched and chemically and mechanically polished together with low κ dielectrics.