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Mentoring aims to improve careers and create benefits for the participants' personal and professional lives. Mentoring can be an individual or a shared experience for a group, while the mentor’s role remains the same in both models. Mentors should increase confidence, teach, inspire, and set examples, helping the mentees to mould their path, contributing to the pursuit of their personal and professional goals. This study aims to report on the experience of early-career medical physics professionals and postgraduate students participating in a global mentoring program and to assess the impact of this activity on their professional development. The objectives of this mentoring program are to develop leadership roles among young medical physicists and to provide guidance and support. An online questionnaire was administered to the mentee participants. The analysis of their responses is reported in this work and the current status of the programme was examined using a SWOT analysis.In general, the mentoring experience had a positive impact on the mentees. The mentors were found especially helpful in the decision-making situations and in other conflicts that may arise with career development.Additionally, the mentees felt that mentoring contributed to the development of leadership skills required for the job market and assist in personal development. This paper concludes that participation of young medical physicists in a mentoring group program is beneficial to their career and therefore should be encouraged. Refereed/Peer-reviewed

The EXO-200 experiment searched for neutrinoless double-beta decay of $^{136}$Xe with a single-phase liquid xenon detector. It used an active mass of 110 kg of 80.6%-enriched liquid xenon in an ultra-low background time projection chamber with ionization and scintillation detection and readout. This paper describes the design and performance of the various support systems necessary for detector operation, including cryogenics, xenon handling, and controls. Novel features of the system were driven by the need to protect the thin-walled detector chamber containing the liquid xenon, to achieve high chemical purity of the Xe, and to maintain thermal uniformity across the detector., Manuscript updated in response to JINST reviewer comments

A promising Mg-Zn-Y alloy with the long-period stacking ordered (LPSO) second phase has been developed for about twenty years. Because the LPSO phase has the unique 18R crystal structure, particularly for its packing sequence along [0001], as well as it plays an important role in strengthening mechanisms, it is interesting to clarify in terms of mechanical properties and deformation mechanisms. In this study, uniaxial micro-pillar compression tests are conducted on LPSO along the [0001] direction. At the same time, nanoindentation system equipped with the Berkovich tip is used to extract the basic mechanical properties of (0001) plane. The basal dislocations are found to be activated first, causing the bending of the sample. The bending would lead to the shear stress field downward and thus would cause the nucleation and movement of prism dislocations with [0001] Burgers vector. Prism dislocations can form the fatal 45° slip trace inside the micro-pillar and finally go through the whole sample causing fracture. The basal dislocations are found at the Zn6Y8-Mg interface which might be originated from the local strain field between them.

The open-cell porous Ti-6Al-4V structure with high porosity, intended to be applied as replacement for human cancellous bone, were fabricated by electron beam melting (EBM). Computer aided design (CAD) was applied to design porous structures using the same unit cell with different unit cell sizes from 2.5 to 4 mm, different ligament widths from 600 to 900 μm, and different pore sizes from 1200 to 1800 μm, in order to achieve high porosity of 80% in avoiding the stress shielding effect. In comparison with the CAD designs and the EBM samples, there were minor discrepancies in terms of pore size and ligament width, mainly a result of melting pool. The measured data on the Young's modulus and yield strength of the EBM porous samples can be predicted by the Gibson and Ashby model. All samples with high porosity were found to match well with cancellous bone, with Young's modulus of 2 GPa and yield stress of 31 MPa, effective to diminish the risk of stress shielding effect. For porous EBM sample with high 80% porosity, the work of fracture can increase from 15.9 to 47.6 kJ/m2 with increasing ligament width from 600 to 900 μm.

Electrical and thermal transport properties of the Heusler-type alloys, Ru2VAl1−xGax (x = 0.0–1.0) were studied by means of the electrical resistivity, Seebeck coefficient, and thermal conductivity measurements. All studied compounds show weak metallic characteristics with a low residual resistivity ratio. In addition, the Ru2VAl1−xGax alloys with x ≤ 0.75 show an n-type thermoelectric conduction from 10 to 300 K, while Ru2VGa displays p-type conduction. The estimated Fermi energy of these materials is higher than 0.5 eV, endorsing their metallic character. From the thermal conductivity study, we noticed that low-temperature thermal conductivity decreases with increasing Ga content for x ≤ 0.5 and then increases with further Ga substitution. This observation is essentially due to the change in the phonon scattering processes as a result of the substitution of heavier Ga atoms into the Al sites of Ru2VAl. It is important that an enhanced thermoelectric figure of merit ZT was found in Ru2VAl0.25Ga0.75, about seven times higher than that in Ru2VAl.

In ultra-precision machining, diamond turning is widely applied for optical components and die cores. When operating diamond turning, the tool wear is among the most significant concerns, which causes the deterioration of machining quality and the waste of material and time. The tool wear is unable to be assessed by naked eyes, a tedious off line measurement is employed for evaluating the tool wear. In this paper, an optical method using laser-light scattering to evaluate the tool wear is proposed for maintaining the machining quality and determining the appropriate timing for tool change while manufacturing light guide plate. In this optical method, the progress of the tool wear of nose radius is monitored by the scattered light beams from the machined surface. The incident angle between 20 and 30 degrees is found to provide the best results for monitoring the tool wear.

PURPOSE/OBJECTIVE(S) To report on rectal dosimetry and toxicity outcomes in men with prostate cancer (PCa) treated with I125 low-dose rate brachytherapy (LDR-BT) with or without hydrogel (HS) or hyaluronic acid (HA) rectal spacer (RS) insertion. The working hypothesis is the increased retroprostatic distance achieved from RS insertion results in reduced rectal dosimetry and subsequent reduction in rectal toxicity outcomes. MATERIALS/METHODS Seventy consecutive men treated with LDR-BT between December 2017 and July 2019 were included in this study, twenty-eight (40%) men had RS insertion according to the preference of the referring urologist, compared to a group of forty-two men (60%) without RS. Descriptive statistics were used to compare the RS safety, dosimetric effects on organs at risk (rectum and urethra), as well as gastrointestinal (GI) and genitourinary (GU) toxicities (assessed using the CTCAEv4) between the two groups. RESULTS The mean prostate-rectal separation with RS at mid prostate was 9.9mm (SD 2.8mm). There were no post-operative complications for RS insertion. There was significantly reduced rectal dosimetry in RS group vs non-RS group, the median RV100 was 0cc (IQR = 0-0.0cc) vs 0.4cc (IQR = 0.1-1.1cc) (P < 0.001) respectively. Mean rectal D1cc and D2cc were 52.4% vs 84.2% (P < 0.001) and 45.7% vs. 70.0% (P < 0.001) for RS and non-RS group respectively. There were no discernible differences in the mean urethral D20, D5, and D1. There were significantly less ≥ grade 1 acute and late GI toxicities in the RS group when compared to the non-RS group (0% vs 24% P = 0.004 for acute GI toxicity: 4% vs 33%, P = 0.003 for late GI toxicity). Strong association remained for RS with late GI toxicity (odds ratios < 0.2) even after accounting for the confounding effects of post-implant RV100, D1cc and D2cc. CONCLUSION Insertion of RS in men treated with LDR-BT is safe and results in significantly lower values in rectal dosimetry. The reduction in rectal dosimetry with RS insertion translates into significantly reduced rates of acute and late GI toxicities.

During recent years, diamond wire sawn (DWS) multicrystalline silicon (mc-Si) wafers have been widely used to reduce the production costs; however, these wafers need additional process treatments such as reactive ion etching (RIE) or metal-catalysed chemical etching (MCCE) to form a surface with relatively low reflectivity. Although the absolute power conversion efficiency of the solar cell could be improved by 0.3-0.5% through the introduction of such surface treatments, the production costs would also be increased. In this study, an improved production-scale acidic texturization with additives is used to texture the surfaces of DWS mc-Si wafers, giving a similar weighted averaged reflectance (WAR) of 19.69% as slurry-cut wafers. The effect of the texturization process on the surface morphology, WAR and performance of the DWS mc-Si cells is discussed.

Y2O3 and Al2O3 were in-situ atomic layer deposited (ALD) on pristine GaAs(001)-46 reconstructed surfaces without surface pretreatments. We have studied the border and interfacial traps in both hetero-structures using the measured electrical responses. On the basis of frequency dispersion analysis of the capacitance-voltage (CV) characteristics, we conclude that Y2O3 has effectively passivated GaAs surface with a much lower interfacial trap density (Dit) than Al2O3 as the gate dielectric. The quasi-static CV and conductance measurements are in agreement with the above conclusion. We have demonstrated an excellent ALD-Y2O3/GaAs interface with low Dit's of (0.52)1012eV1cm2 through the whole GaAs band gap without a mid-gap peak feature. Display Omitted

Molecular beam epitaxy (MBE) HfO2 films ~ 1.5 nm thick were directly deposited on freshly grown GaAs(001)-4 × 6 reconstructed surfaces. The hetero-structure exhibits outstanding thermal stability up to 900 °C with excellent capacitance-voltage (C-V) and leakage current density-electric field (J-E) characteristics. We have extracted low interfacial trap densities (Dit's) with minimum value of 1.3 × 1011 eV− 1 cm− 2 from the measured quasi-static C-V (QSCV) characteristics. The smallest frequency dispersion of the C-Vs for the MBE-HfO2/p-GaAs(001) is ~ 5.2% at frequency range of 500 to 1 MHz and no trap-induced humps were observed in the C-Vs, as measured at 100 °C and 150 °C. Also, the leakage current density remains low of 10− 8(A/cm2) at E

In-situ atomic layer deposition (ALD) Y2O3/Al2O3 in bi-layered and sub-nano-laminated structures were stacked on pristine GaAs(001) substrates for fabricating metal-oxide-semiconductor capacitors. The bi-layered Y2O3/Al2O3 showed an enhanced effective dielectric constant from 11.1 to 15.6 in capacitance-voltage characteristics with post deposition annealing to 900C. No new oxide phase formed as carefully examined using synchrotron radiation X-ray diffraction and cross-sectional high-resolution scanning tunneling electron microscopy. We designed and grew sub-nano-laminated Y2O3/Al2O3 multi-layers to simulate the mixing of gate oxides, and observed an enhanced dielectric constant of 14.8 for the as-deposited sample. Both high-temperature mixed and sub-nano-laminated ALD Y2O3/Al2O3 exhibit high dielectric constant, low leakage current ~108A/cm2 and low interfacial trap density with GaAs(001), promising for high applications in future GaAs metal-oxide-semiconductor devices. Display Omitted High dielectric constant () in 900C annealed ALD Y2O3/Al2O3 bi-layerHigh in ALD sub-nano-laminated (super-cycled) Y2O3/Al2O3 multi-layersEnhancement of dielectric constant without new structure formationExcellent CVs with low leakage current for Y2O3/Al2O3 on GaAs(001)

The fan-out packaging technology has recently been adopted in mobile application processors due to its advantages in form factor, fine pitch traces, and efficient thermal dissipation. This paper demonstrates heterogeneous integration on a fan-out redistribution layer (RDL) interposer. The package has a full-reticle size Si die and two HBMs. Si die and memory modules are attached to a fanout RDL and are then attached to a multilayer substrate. This advanced package meets both electrical and mechanical requirements. The fanout RDL interposer is comprised of polymer and copper traces, and it is relatively mechanically flexible. Such flexibility enhances C4 joint integrity, and allows the new package to scale up its size to meet more complex functional demands.

Aiming to study the primary cosmic-ray mass composition up to the knee energy region with the Tibet underground water-Cherenkov muon-detector array (MD), we propose to extend the dynamic range of each MD detector with an 8-inch PMT (Beijing Hamamatsu CR365) and a 3-inch PMT (HZC XP72B22). We carried out a series of tests on the candidate 3-inch XP72B22 PMT to examine whether it can meet our requirements. The measurement results showed that the XP72B22 has a wide dynamic range of 3 orders of magnitude and a linear response up to ∼105 photoelectrons (PEs) at the supply voltage of 700 V. Combined with previous test results of the CR365, these two types of PMT can achieve an equivalent dynamic range from 30 to 106 PEs. As a result, an MD cell is able to detect cosmic rays around the knee energies by adding the CR365 and the XP72B22.

Magnetic properties of melt spun Co 86.5 Hf 10.5 MB 2 ribbons with refractory elements substitution (M=Cr, Nb, Ti, Zr) have been studied. For ternary Co 86.5 Hf 11.5 B 2 ribbon, permanent magnetic properties of B r =0.71 T, i H c =192 kA/m, and (BH) max =34.4 kJ/m 3 are obtained, and they are significantly improved to B r =0.73–0.76 T, i H c =136–216 kA/m and (BH) max =38.4–52.8 kJ/m 3 with M substitution. Summarized with the results of x-ray diffraction refinement, thermal magnetic analysis, and transmission electron microscopy, the Co 86.5 Hf 10.5 MB 2 nanocomposites following the optimal crystallization treatment mainly consist of orthorhombic 7:1 and face-center-cubic Co phases. Fine microstructure with average grain size in the range of 12.5−19.6 nm promotes exchange coupling effect between magnetic grains, thus improving permanent magnetic properties. The magnetic field dependence of coercivity reveals that coercivity of the studied Co 86.5 Hf 10.5 MB 2 nonocomposites is mainly governed by the reverse domain nucleation mechanism.

Display Omitted First demonstration of single-crystal atomic layer deposited oxide on GaAs(001).Attainment of very thin single crystal ALD-Y2O3 1nm thick on GaAs(001).Thin ALD-Y2O3 film with excellent crystallinity having FWHM of ~0.033?.Lowest frequency dispersion ever achieved in the ALD-oxides on n-type GaAs(001).Thermodynamic stability at high temperatures of 900?C. In situ atomic layer deposited (ALD) Y2O3 films 1-5nm thick on GaAs(001)-4i?6 reconstructed substrates were found to be single crystalline. The epitaxial growth between the oxide films and GaAs was first observed using reflective high energy electron diffraction (RHEED) and later studied using high-resolution synchrotron radiation X-ray diffraction. The Y2O3 films are of cubic phase and have (110) as the film normal; the orientation relationship between the Y2O3 films and the GaAs substrates was determined to be Y2O3(110)001] 1 ? 1 0 ]//GaAs(001)110] 1 1 ? 0 ] . The frequency dispersion of the measured capacitance-voltage (C-V) curves of the single crystal ALD-Y2O3/GaAs(001)-4i?6 is ~7% for p-GaAs and ~14% for n-GaAs (1MHz to 100Hz), lowest ever achieved in the ALD-oxides on GaAs(001).

Display Omitted Demonstration of using Al2O3/Y2O3 as common gate stacks on InGaAs, GaSb and Ge.Record high device performance of Al2O3/Y2O3 on GaSb for p-MOSFETs.Drain current of 1.5mA/µm and transconductance of 770µS/µm on InGaAs for 1µm gate length n-MOSFETs.CMOS compatible process. Y2O3, as a common high ? gate dielectric, has been directly deposited on (In)GaAs, GaSb, and Ge using electron beam evaporation in ultra-high vacuum. These semiconductors have distinctly different chemical bonding and surface electronic characteristics. No interfacial passivation layer was employed. High-quality Y2O3/semiconductor interfaces have been achieved, resulting in low interfacial trap densities and high-temperature thermal stability, essential for the CMOS compatible process. Self-aligned inversion channel n-InGaAs, p-GaSb, and p-Ge MOSFETs have been fabricated with excellent device performances.

Poly-methyl-methacrylate thin films were deposited by plasma polymerization under different radio-frequency discharge powers, monomer partial pressures, and deposition times. Surface profiler was used to evaluate the thickness and deposition rates of deposited films; Fourier transform infrared spectroscopy for the microstructures; X-ray photoelectron spectroscopy for the surface chemical compositions and atomic force microscope for the surface morphology. In addition to the as-deposited PMMA films, some selected films were further treated by oxygen to modify their surfaces. After thorough material characterizations, the films were used as substrates to culture human hepatocytes for testing their biocompatibility. Results of the cell culture were assessed by trypsin cell count, ELISA and MTT assay. It is found that the human hepatocytes can proliferate and perform urea synthesis well on the deposited poly-methyl-methacrylate thin films with or without oxygen treatment.

We report here the fabrication of periodic arrays of size- shape-, and spacing-controllable Si nanopores on single-crystalline (110)Si and (111)Si substrates by using our proposed approach, which is based on the self-assembled polystyrene nanosphere lithography in conjunction with the use of oxygen plasma treatments and KOH anisotropic etching processes. Compared with other works, the facile approach proposed here offers a much simpler and low-cost scheme which does not require the use of additional metal-film hard masks deposition and stripping processes. By adjusting the KOH etching duration, the Si nanopore size can be effectively tuned and controlled. The Si nanopores formed on (110)Si and (111)Si were found to be heavily faceted, and their faceted morphologies were mainly determined by the crystal orientations of the Si substrates used. Furthermore, the results of the ultraviolet-visible spectroscopic measurements revealed that the (110)Si substrate with nanopore arrays exhibited significant antireflection properties, and its optical reflectance was found to decrease with increasing the etched nanopore size. The obtained results present the exciting prospects that the combined approach presented here could have significant potential for use in Si-based optoelectronic devices.

In a manufacture system, the inventory control is one of important issues. This paper proposes a fuzzy economic order quantity (EOQ) inventory model for solving the inventory control problem in the manufacture system. Firstly, this paper discusses the square roots of a trapezoidal fuzzy number. Secondly, the square root of fuzzy number is applied to the EOQ inventory model in the manufacture system.

After the processing of a clock dial, the precision dimension and uniform distribution of the tool-trace pattern on the dial surface have a connection with luster image and attractiveness, which in turn would have an impact on the additional values and prices for a clock. Through a systematic investigation among the lathe structure, process parameter and cutting-tool geometry in advance, the total results indicated that the rigidity of the lathe structure and the precision of the slider movements are excellent and they had only a little effect on the surface-related quality for a dial face turning. Hence, the combination of process parameter and cutting-tool angle becomes more essential. End face turning simulation and experiment of a copper alloy were thus conducted in this paper, and the chip formation process and machined surface-related quality are investigated, respectively. The effects of cutting tool geometry and process parameter on the results of chip formation, surface rough, tool-trace pattern and luster uniformity are investigated, and these results are also compared with each other. The results show that when larger clearance and rake angles used in conjunction with a lower feed rate, no matter how much cutting speed was enhanced, the surface-related quality of a dial surface is not good. However, when these two larger angles used combined with a larger feed rate, the quality of a dial surface would slightly be improved. By using smaller clearance and rake angles along with the higher feed rate and cutting speed would obtain a better surface-related quality with uniform luster and attractiveness.

Al-doped ZnO powders were synthesized via solid reaction between Zn(OH)2 and Al(OH)3 and consolidated by spark plasma sintering (SPS) to fabricate fine-grained Zn1−xAlxO ceramics as a thermoelectric material. X-ray diffraction and spectrophotometer experiments revealed that Al doping into ZnO is enhanced by the present process, and consequently the SPS-processed Zn1−xAlxO samples show significantly improved electrical conductivity as compared with those prepared via mixing ZnO and Al2O3 oxide powders. Because of the combined effect of Al doping and grain refinement, the present Zn1−xAlxO ceramics show much lower thermal conductivity, which also results in an enhanced dimensionless figure of merit (ZT), than un-doped ZnO oxides prepared also by SPS.

Last decades, rare-earth (RE) containing nanocomposites with improved remanence, B r , and maximum energy product, (BH) max , have been investigated extensively for bonded magnet applications. However, the demand for rare-earth permanent magnets is rapidly increased, leading to the shortage and price rising of rare earth elements. Therefore, it is significant to explore the RE-free permanent magnetic materials which are possible for industrial applications. Recently, RE-free Co-Hf-B system has been reported to exhibit attractive permanent magnetic properties [1-3]. Especially, Br=0.75T, i H c = 248 kA/m, and (BH) max = 61.6 kJ/m3 have been achieved in Co 85 Hf 12 B 3 recently [3]. However, limited study related to the elemental substitution effect on the magnetic and structural characterizations of Co-Hf-B alloys is available. In the paper, Co-rich Co 86.5 Hf 11.5 B 2 is selected as an initial composition, and the effect of refractory elements substitution, including Ti, Cr, Nb, Zr, on the structural and magnetic properties of Co 86.5 Hf 10.5 MB 2 alloys are investigated. The melt spinning method is adopted to prepare the isotropic nanocomposite samples at a high wheel speed of 40 m/s in this work.

Calla lily chlorotic spot virus (CCSV), a tospovirus infecting Calla lily (Zantedeschia spp.) in Taiwan, with symptoms of chlorotic spots on leaves and stems, was previously reported serologically but distantly related to Watermelon silver mottle virus (WSMoV). To further characterize the virus, DNA fragments corresponding to the S RNA of the virus were amplified from total RNA extracted from CCSV-infected plants of Nicotiana benthamiana, cloned and sequenced. The full-length viral strand of the S RNA was determined as 3,172 nucleotides in length, with an inverted repeat at the 5' and 3' ends and two open reading frames in an ambisense arrangement. The 3'-terminal sequence (5'-AUUGCUCU-3') of the viral S RNA was found identical to those of other tospoviruses, confirming that CCSV belongs to the genus Tospovirus. The N and the NSs proteins of CCSV share low amino acid identities, 20.9 to 65.1% and 19.9 to 66.1%, respectively, with those of reported tospoviruses. The phylogenetic dendrogram of the N protein of CCSV compared with those of other tospoviruses in WSMoV serogroup indicates that CCSV is a distinct tospovirus. Thus, based on the results of molecular characterization of S RNA, we conclude that CCSV is a new tospovirus species belonging to WSMoV serogroup.

The fatigue and fracture behaviors of the (Zr58Ni13.6Cu18Al10.4)99Nb1 bulk amorphous alloy are investigated by four-point-bend fatigue tests. The material shows a fatigue–endurance limit and fatigue ratio of 559 MPa and ∼ 0.328, respectively. The fracture toughness is estimated to be about 26–43 MPa m . Shear bands were found to be oriented greater than 45° on the tension surface and smaller than 45° on the compression surface, with respect to the outer fiber-stress direction of the sample. The density of the shear bands on the tension side is greater than that on the compression side. Many wavy shear bands perpendicular to the outer fiber-stress direction also formed on the tension and compression surfaces during the fatigue process. The fracture surface can be divided into four regions: crack initiation, crack propagation, fast fracture, and melting regions. The fracture mechanism is discussed.

In vitro morphogenesis including somatic embryogenesis was studied in five orchids, Cymbidium, Epidendrum, Oncidium, Paphiopedilum and Phalaenopsis. 1) Sections of pseudobulbs, rhizomes and roots of Cymbidium ensifolium var. misericors were induced to formed totipotent calli on a modified MS medium supplemented with 2,4-D and thidiazuron (TDZ). Subculturable calli formed embryoids on a modified MS medium supplemented with BA or TDZ. The embroids developed into rhizomes and, eventually, rhizomes produced normal plantlets. 2) Small transparent tissues formed from surface and cut ends of root, stem, leaf and flower-stalk intenodes of Epidendrum radicans on a modified 1/2-MS basal medium with or without thidiazuron (TDZ) after 1-2 weeks of culture. In light, the transparent tissues enlarged and turned into green organized masses on most of the explants. The organized masses with young protocorm-like bodies (PLBs) proliferated on a hormone-free basal medium, and TDZ promoted the proliferation rate. Normal plantlets converted from PLBs on the same TDZ-containing medium after 1 months of culture. 3) In Oncidium, embryogenic calli were induced in vitro by using root, stem, leaf and flower stalk internode as explants, and healthy plantlets were successfully obtained from the callus cultures. In addition, direct somatic embryogenesis was established by using leaf segments as explants on a modified 1/2strength MS medium. 4) In Paphiopedilum, totipotent callus was induced from seedderived protocorms. The calli were induced to form “globular granules”, and then these granules transformed into PLBs. Eventually, well-developed plantlets were obtained from these callus-derived PLBs. 5) For Phalaenopsis propagation, seedderived protocorms were induced to formed callus. The “proembryo-like structures” were found on the surface of the callus before formation of PLBs, and these PLBs also could convert into well-developed plantlets. INTRODUCTION In vitro morphogenesis and efficient micropagation protocols of several orchids have been studied. These orchids are usually derived from dividing potted plants or seeds. Propagation of this genus, either by seed or by in vitro culture, is still considered difficult. We obtained three kinds of morphogenesis from callus cultures of Cymbidium ensifolium var misericors: rhizomes, shoot buds and granular embryoids. Healthy plantlets were obtained following regeneration via callus-derived rhizomes and granular embryoid-like structures. Similar morphogenesis was also found in Paphiopedilum, Oncidium, and Phalaenopsis. Practical protocols for mass propagation of these orchids have been developed. Mass suspension cultures of these orchids and plant regeneration from these cells are currently being attempted. Plant Regeneration from Callus Culture of Cymbidium ensifolium var. misericors Explants from rhizomes, pseudobulbs and roots formed callus on 1/2 MS medium supplemented with 10 mg/l 2,4-D and 0.1 mg/l TDZ after 2-3 passages of subculture with a 6-months interval. Callus was maintained well in the presence of 3.3 mg/l 2,4-D combined with 0.1 mg/l TDZ. Three distinct morphogenetic events, including rhizome formation, shoot bud formation and production of globular granules were observed on basal medium either without growth regulator supplements, with 1 mg/l TDZ, or with 5 mg/l BA after 1-2 months of culture. About 40.2 % of callus-derived granules developed 115 Proc. IInd IS on Biotech. of Trop & Subtrop. Species Eds: W.-C. Chang and R. Drew Acta Hort 692, ISHS 2005 into rhizomes when transferred onto a modified 1/10 MS medium for 50 days. Eventually, plantlets were obtained from the shoot buds of the callus-derived rhizomes (Chang and Chang, 1998). Effect of TDZ on Bud Development of Cymbidium sinense Wild Seed-derived rhizomes were able to initiate shoot buds in the presence of 0.01-1 mg/l TDZ. However, the further proliferation of rhizomes was retarded by TDZ. Plantlets (about 10 cm in height) were obtained from rhizome-derived shoot buds on medium supplemented with 0.5 mg/l NAA and 1 g/l after 4 months of culture. About 9.1 % and 73% of regenerated plants flowered normally in the 2 year and the 3 year, respectively. This result indicated that the treatment of TDZ during bud development may shorten the juvenile phase of this orchid species (Chang and Chang, 2000a). In Vitro Flowering of Cymbidium ensifolium var. misericors Callus-derived rhizomes produced flowers precociously on a modified 1/2 MS medium containing NAA with 2iP, BA and TDZ after 100 days of culture. TDZ at 3.3-10 μM or 2iP at 10-33 μM combined with 1.5 μM NAA gave the best response on flower induction. Although the in vitro flowers were smaller in size, their morphology is normal. These flowers bloomed for about two weeks in vitro. The pollens of these in vitro flowers are viable, and germinated on an agar medium after 12 hours of culture (Chang and Chang, 2000b). Efficient Production of Protocorm-like Bodies of Epidendrum Flower stalk internodes formed a large number of PLBs on 1/2 MS medium supplemented of TDZ. These PLBs grew well and proliferated more on the same medium. The best response on PLB production was found at a modified 1/2 MS medium containing 825 mg/l NH4NO3, 950 mg/l KNO3 and 40 g/l sucrose. BA, kinetin and zeatinriboside promoted PLB proliferation and subsequent shoot formation. The optimized procedure required about 12-13 weeks from the initiation of PLBs to plantlet formation. Somatic Embryogenesis and Plant Regeneration of Oncidium Protocols for in vitro plant regeneration via direct or indirect somatic embryogenesis of Oncidium spp. have been established. 1) Leaf segments of the cultivar ‘Gower Ramsey’ were induced to directly form somatic embryos on 1/2-MS medium supplemented with TDZ. Plantlet formation from these somatic embryos was achieved on the same basal medium devoid of plant growth regulators (Chen et al., 1999). 2) Yellowish embryogenic calluses derived from leaf, root and stem explants of the cultivar ‘Gower Ramsey’ were induced and maintained well on 1/2-MS medium supplemented with 2,4-D and TDZ. Somatic embryos formed from these calluses on the same basal medium supplemented with NAA and TDZ. Plantlet conversion was made on the same basal medium devoid of plant growth regulators (Chen and Chang, 2000b; Wu et al., 2004). 3) Flower stalk explants of the cultivar ‘Sweet Sugar’ formed somatic embryos on TDZ-containing medium, and plantlets derived form these embryos were obtained on the same medium (Chen and Chang, 2000a). Leaf segments taken from regenerated plantlets of cv. Sweet Sugar were induced to obtain repetitive somatic embryogenesis (Su et al., in press). The leaf culture system has been further used to study the effects of tissue culture conditions (Chen and Chang, 2002), explant characteristics (Chen and Chang, 2002), plant growth regulators (auxins, auxin inhibitors, cytokinins, GA3, growth retardants, ACC and ethylene inhibitors) (Chen and Chang, 2001; Chang and Chang, 2003) on direct somatic embryogenesis. Plant Regeneration from Protocorm-derived Callus of Paphiopedilum Explants from seed-derived protocorms were induced to form yellowish callus on a 1/2 MS medium supplemented with 1-10 mg/l 2,4-D and 0.1-1 mg/l TDZ. The callus

The failure of flip chip solder joints through the dissolution of the Cu metallization was studied. From the location and geometry of the dissolved Cu, it can be concluded that current crowding played a critical role in the dissolution. It can also be concluded that temperature, as an experimental variable, is not less import than the current density in electromigration study. Experimentally, no evidence of mass transport due to thermomigration was observed.

The temperature dependence of the photoluminescence (PL) emission spectra of self-organized InAs/GaAs quantum dots (QDs) grown under different growth conditions in the range 20-300K has been investigated. Three InAs QD samples were grown on (100) 2º-tilted toward (111)A Si-doped GaAs substrates by metal-organic chemical vapour epitaxy (MOVPE), with various size uniformities and dot densities. Observing the measured PL spectra at 20K, the differences caused by size uniformities among the three samples were obvious. The PL spectra were simulated with rate equations, taking into account the carrier relaxation between the first excited state and the ground state. Interestingly, the calculated relaxation lifetimes at 20K were 198ps, 139ps and 54ps for the samples. The temperature dependent PL spectra were also simulated using the same model. Based on the calculated values of temperature dependent relaxation lifetimes, the differences in changes with temperature among the three samples are discussed. The results are consistent with the thermal redistribution effect.

Influence of material strain hardening on the mechanics of steady continuous roll- and edge-bending mode in the four-roll plate bending process was investigated. An analytical method to solve the governing differential equations for large deflection of elastoplastic thin plate with any general strain hardening law of material was developed. Numerical results for the physical quantities of (i) the shift of plate contact angle with rolls, (ii) the forces applied on rolls and (iii) the position setup of side roll, etc. were obtained and shown graphically as a function of the desired finish curvature of plate made of linear strain hardening material. Comparison of the results with perfectly plastic material is also made.

TT virus (TTV) is transfusion-transmissible but its involvement in post-transfusion hepatitis is uncertain. To investigate the potential association of TTV with liver diseases, the prevalence of TTV DNA was tested by semi-nested PCR in 113 carriers of hepatitis C virus (HCV), 10 patients with acute liver failure, 11 patients with cryptogenic cirrhosis and 200 control blood donors. Thirty-seven of these patients underwent liver transplantation and were tested pre- and post-transplantation. TTV DNA was semi-quantified in serial samples from seven patients with unexplained post-transplant hepatitis. TTV genotyping was performed on samples from 28 patients by sequence analysis. The prevalence of TTV DNA in blood donors was 1.5% and 17% in HCV infected haemophiliacs. In patients with acute or chronic liver disease or hepatitis, 6 to 27% prevalence was observed. After liver transplantation, the prevalence of TTV DNA increased from 16 to 46% (P < 0.01). In patients who developed unexplained hepatitis post-transplantation, TTV viraemia did not parallel ALT levels. TTV DNA either increased in titre or became detectable shortly after transplantation, suggesting that either TTV was transfusion-transmitted, or, more likely, that immunosuppression caused a recurrence of low level or undetectable TTV viraemia. TTV had considerable genomic diversity in the N22 region, corresponding to at least 4 genotypes. Genotype 2 was found in 14/28 patients.

This paper presents a mathematical model to simulate the mechanics in a steady continuous bending mode for four-roll thin plate bending process. The differential equations governing the large deflection bending of elastic-perfectly plastic thin plate are derived by modelling the loading and unloading deformation of the operational process. Through a semi-analytical solution of the system equations, the physical quantities of (i) the deformation and stress resultants of bend plate, (ii) the springback, (iii) the shift of contact-angle of bend plate with rolls, (iv) the applied forces on rolls, (v) the bending torque and power, and (vi) the position of the operative side roll, etc., associated with bending of a plate to an anticipated curvature, for single-pass bending operation, are predicted and discussed.

An analytical approach has been developed to study the mechanics of the continuous plate edge bending mode of the four-roll bending process, solving the governing differential equation for the large deflection of an elastoplastic thin plate with an arbitrary strain-hardening law for the material. Numerical results for the physical quantities of: (i) the shift of the plate contact angle with rolls; (ii) the forces applied on the rolls; and (iii) the positional set-up of the side roll; are obtained and shown graphically as a function of the anticipated curvature of plate made of linear strain hardening material. The effect of material strain hardening on the mechanics is studied and compared with those for a perfectly plastic material.

Load and speed are the most important sliding-wear parameters for coated tools used against counter materials but have been rarely discussed, particularly the popular CAP-TiN-coated tool. This study presents a wear test to profile the tribobehavior of a CAP-TiN-coated steel tool contacting with chromium steel as a function of load and speed. Wear-loss and friction-coefficient measurements were assessed to evaluate the sliding-wear resistance, and scanning electron microscopy and optical microscopy were used to identify wear modes. Experimental results show that the wear modes observed were polishing wear and mass transfer in low wear-load conditions of less than 39.2 N, while low stress-abrasion wear, macroparticle drop-off, Brinelling and mass transfer were found in high wear-load conditions ranging from 39.2 to 88.2 N. Only mass-transfer and macroparticle drop-off wear modes were found at high sliding speeds. If a low wear-load was employed independent of the sliding speed (up to 37 m min−1 in this case) it had a minor effect on wear loss because the detrimental wear modes such as low stress abrasion and Brinelling do not occur. This study reveals the wear-immune region of the CAP-TiN-coated tool. Macroparticles, which are usually thought to reduce wear life, do not affect the wear performance at all in this dry sliding contact wear test.

The objective of this study was to develop a controlled-oxidant-release technology combining in situ chemical oxidation (ISCO) and permeable reactive barrier (PRB) concepts to remediate trichloroethene (TCE)-contaminated groundwater. In this study, a potassium permanganate (KMnO 4 )-releasing composite (PRC) was designed for KMnO 4 release. The components of this PRC included polycaprolactone (PCL), KMnO 4 , and starch with a weight ratio of 1.14:2:0.96. Approximately 64% (w/w) of the KMnO 4 was released from the PRC after 76 days of operation in a batch system. The results indicate that the released KMnO 4 could oxidize TCE effectively. The results from a column study show that the KMnO 4 released from 200 g of PRC could effectively remediate 101 pore volumes (PV) of TCE-contaminated groundwater (initial TCE concentration = 0.5 mg/L) and achieve up to 95% TCE removal. The effectiveness of the PRC system was verified by the following characteristics of the effluents collected after the PRC columns (barrier): (1) decreased TCE concentrations, (2) increased ORP and pH values, and (3) increased MnO 2 and KMnO 4 concentrations. The results of environmental scanning electron microscope (ESEM) analysis show that the PCL and starch completely filled up the pore spaces of the PRC, creating a composite with low porosity. Secondary micro-scale capillary permeability causes the KMnO 4 release, mainly through a reaction–diffusion mechanism. The PRC developed could be used as an ISCO-based passive barrier system for plume control, and it has the potential to become a cost-effective alternative for the remediation of chlorinated solvent-contaminated groundwater.