Changes in anisometropia by age in children with hyperopia, myopia, and antimetropia.

Anisometropia is a unique condition of both eyes and it is associated with vision problems such as amblyopia and reduced stereoacuity. Previous studies have not reported its change pattern by age and its correlation with the refractive condition of both eyes. This study aims to compare the changes in anisometropia by age in children with hyperopia, myopia, and antimetropia. In total, 156 children were included. Children aged 3-11 years with anisometropia ≥ 1.00 D were followed up for ≥ 1 year with ≥ 2 visits at two medical centers in Taiwan. Refractive errors by cycloplegic autorefractometry, best-corrected visual acuity, eye position, and atropine use were recorded. The children were divided into hyperopic, myopic, and antimetropic groups. The results showed that anisometropia decreased in children aged < 6 years (3.34-2.96 D; P = 0.038) and increased in older children (2.16-2.55 D; P = 0.005). In children aged 3, 4, 5, and 6 years, the mean anisometropia was higher in children with myopia and antimetropia than in those with hyperopia (P = 0.005, 0.002, 0.001, and 0.011, respectively). The differences were not significant in children aged > 6 years (all P > 0.05). The factors associated with changes in anisometropia were age, refractive group, amblyopia, and strabismus. Anisometropia decreased with age in children younger than 6 years, and the changes in anisometropia was found in children with myopia and antimetropia.

Fabrication and characteristics of highly [Formula: see text]-oriented nanotwinned Au films.

Fine grained and nanotwinned Au has many excellent properties and is widely used in electronic devices. We have fabricated [Formula: see text] preferred-oriented Au thin films by DC plating at 5 mA/cm2. Microstructure analysis of the films show a unique fine grain structure with a twin formation. Hardness tests performed on electroplated [Formula: see text] Au films show a hardness 47% greater than random and untwinned Au. We then achieved direct bonding between two Au [Formula: see text] surfaces operating at 200 °C for an hour in a vacuum oven. The highly-oriented [Formula: see text] nanotwinned Au films could be an ideal material in many gold products.

Low-temperature direct copper-to-copper bonding enabled by creep on (111) surfaces of nanotwinned Cu.

Direct Cu-to-Cu bonding was achieved at temperatures of 150-250 °C using a compressive stress of 100 psi (0.69 MPa) held for 10-60 min at 10(-3) torr. The key controlling parameter for direct bonding is rapid surface diffusion on (111) surface of Cu. Instead of using (111) oriented single crystal of Cu, oriented (111) texture of extremely high degree, exceeding 90%, was fabricated using the oriented nano-twin Cu. The bonded interface between two (111) surfaces forms a twist-type grain boundary. If the grain boundary has a low angle, it has a hexagonal network of screw dislocations. Such network image was obtained by plan-view transmission electron microscopy. A simple kinetic model of surface creep is presented; and the calculated and measured time of bonding is in reasonable agreement.

Effect of grain orientations of Cu seed layers on the growth of <111>-oriented nanotwinned Cu.

We investigate the growth of Cu films on two different Cu seed layers: one with regular <111>-oriented grains and the other with very strong <111>-preferred orientation. It is found that densely-packed nanotwinned Cu (nt-Cu) can be grown by pulsed electroplating on the strong <111>-oriented Cu seed layer without a randomly-oriented transition layer between the nt-Cu and the Cu seed layer. The electroplated nt-Cu grow almost epitaxially on the seed layer and formed <111>-oriented columnar structures. However, with the regular <111>-oriented Cu seed, there is a randomly-oriented transition layer between the nt-Cu and the regular <111>-oriented Cu seed. The results indicate that the seed layer plays a crucial role on the regularity of <111>-oriented nanotwinned Cu.

Unidirectional growth of microbumps on (111)-oriented and nanotwinned copper.

Highly oriented [111] Cu grains with densely packed nanotwins have been fabricated by direct-current electroplating with a high stirring rate. The [111]-oriented and nanotwinned Cu (nt-Cu) allow for the unidirectional growth of Cu(6)Sn(5) intermetallics in the microbumps of three-dimensional integrated-circuit packaging; a uniform microstructure in a large number of microbumps of controlled orientation can be obtained. The high-density twin boundaries in the nt-Cu serve as vacancy sinks during the solid-state reaction between Pb-free solder and Cu and greatly reduce the formation of Kirkendall (or Frenkel) voids.