The amorphous to crystalline phase transformation process is typically known to take place at very high temperatures and facilitated by very high compressive stresses. In this study, we demonstrate crystallization of amorphous ultra-thin platinum films at room temperature under tensile stresses. Using a micro-electro-mechanical device, we applied up to 3% uniaxial tensile strain in 3-5 nm thick focused ion beam deposited platinum films supported by another 3-5 nm thick amorphous carbon film. The experiments were performed in situ inside a transmission electron microscope to acquire the bright field and selected area diffraction patterns. The platinum films were observed to crystallize irreversibly from an amorphous phase to face-centered cubic nanocrystals with average grain size of about 10 nm. Measurement of crystal spacing from electron diffraction patterns confirms large tensile residual stress in the platinum specimens. We propose that addition of the externally applied stress provides the activation energy needed to nucleate crystallization, while subsequent grain growth takes place through enhanced atomic and vacancy diffusion as an energetically favorable route towards stress relaxation at the nanoscale. 相似文献
A nano-mechanical model has been developed to calculate the tensile modulus and the tensile strength of randomly oriented short carbon nanotubes (CNTs) reinforced nanocomposites, considering the statistical variations of diameter and length of the CNTs. According to this model, the entire composite is divided into several composite segments which contain CNTs of almost the same diameter and length. The tensile modulus and tensile strength of the composite are then calculated by the weighted sum of the corresponding modulus and strength of each composite segment. The existing micro-mechanical approach for modeling the short fiber composites is modified to account for the structure of the CNTs, to calculate the modulus and the strength of each segmented CNT reinforced composites. Multi-walled CNTs with and without inter-tube bridging have been considered. Statistical variations of the diameter and length of the CNTs are modeled by a normal distribution. Simulation results show that CNTs inter-tube bridging, length and diameter affect the nanocomposites modulus and strength. Simulation results have been compared with the available experimental results and the comparison concludes that the developed model can be effectively used to predict tensile modulus and tensile strength of CNTs reinforced composites. 相似文献
In recent years, neural network-based machine translation (MT) approaches have steadily superseded the statistical MT (SMT) methods, and represents the current state-of-the-art in MT research. Neural MT (NMT) is a data-driven end-to-end learning protocol whose training routine usually requires a large amount of parallel data in order to build a reasonable-quality MT system. This is particularly problematic for those language pairs that do not have enough parallel text for training. In order to counter the data sparsity problem of the NMT training, MT researchers have proposed various strategies, e.g. augmenting training data, exploiting training data from other languages, alternative learning strategies that use only monolingual data. This paper presents a survey on recent advances of NMT research from the perspective of low-resource scenarios.
The effects of feeding rumen-inert fat sources on production responses of lactating dairy cows have been well reported but less thoroughly described in lactating dairy buffalo. The objective of this study was to investigate the effect of oil and 2 different rumen-inert fat sources on dry matter intake, milk yield, milk composition, and milk fatty acid (FA) profile in Nili Ravi buffalo. Twelve multiparous mid-lactating Nili Ravi buffaloes received 4 treatments in a 4 × 4 Latin square design with a period length of 21 d. The treatments were (1) the basal diet without supplementation of oil or fats (CTRL), (2) the basal diet supplemented with canola oil (CO), (3) the basal diet supplemented with calcium salts of palm FA (Ca-FA), and (4) the basal diet supplemented with high palmitic acid (PA). Dry matter intake was decreased by 4.4% in the CO compared with Ca-FA and PA. Milk yield and milk fat yield were increased by 7.8 and 14.3%, respectively, in CO, Ca-FA, and PA compared with the CTRL. Milk fat content increased by 7.5%, whereas milk fat yield tended to increase with the supplementation of Ca-FA and PA compared with CO. No effect on milk yield and milk composition was observed in Ca-FA versus PA treatments. The yield of medium-chain FA was increased by Ca-FA and PA versus CO. The CO treatment increased the yield of long-chain FA compared with Ca-FA and PA treatments. Plasma glucose level was higher in CO, Ca-FA, and PA compared with the CTRL. In conclusion, feeding rumen-inert fats in the lactating buffalo diet proved to be a useful strategy to increase the 3.5% fat-corrected milk yield due to the higher milk fat content in this study. 相似文献
All grades of carbon black contain large amounts of unpaired electrons and organic functional groups. Polymerization reaction is possibly initiated by the unpaired electrons on the surface; the functional groups have promotional effect on the initiation process. All the properties like texture, geometry, surface area, pH of the aqueous slurry, ash content, and elemental composition have effects on the polymerization reaction. These pertinent physicochemical and surface properties of unmodified and modified N 220 carbon black have been studied in relation to N-vinylcarbazole polymerization. 相似文献
The efficacy of combination therapy with cis-diammine-dichloroplatinum (II) (CDDP) and o-(chloroacetyl-carbamoyl) fumagillol (AGM-1470) was evaluated experimentally using a transplantable rat osteosarcoma line, previously established in our laboratory, with a high potential for metastasis. Tumor-bearing male Fischer 344 rats were administered CDDP (2.5 mg/kg) together with, or after discontinuation of, AGM-1470 treatment (10 mg/kg/body weight/week). When CDDP was administered three days after discontinuation of AGM-1470 the most pronounced antimetastatic effects were observed, although the antitumor effect was approximately the same. 相似文献
Lumbosacral defects on 20 patients were covered with a perforator-based flap. Cutaneous perforators derived from the 9th and 10th intercostal arteries, the 4th lumbar artery, and multiple gluteal perforators that penetrate the gluteus maximus muscle were used as vascular pedicles. Minor complications occurred in five cases. Using this method, minimal morbidity of the donor site is expected because the gluteus maximus need not be sacrificed. Accordingly, perforator-based flaps are especially indicated for ambulatory patients, but for paraplegic patients as well. Even in the event of recurrence, another perforator-based or musculocutaneous flap can be elevated from the ipsilateral side because of the presence of multiple perforators in the lumbosacral and gluteal regions. 相似文献
Multiple endocrine neoplasia type 1 (MEN 1) is inherited as an autosomal dominant disorder, characterized by hyperplasia and neoplasia in several endocrine organs. The MEN 1 gene, which is most probably a tumor suppressor gene, has been localized to a 900-kb region on chromosome 11q13. The human phosphatidylinositol-specific phospholipase C beta 3 (PLC beta 3) gene, which is located within this region, was considered to be a good candidate for the MEN 1 gene. In this study, the structure and expression of the PLC beta 3 gene in MEN 1 patients were investigated in more detail, to determine its potential role in MEN 1 tumorigenesis. Southern blot analysis, using blood and tumor DNA from affected persons from seven different MEN 1 families, did not reveal structural abnormalities in the PLC beta 3 gene. To detect possible point mutations, or other small structural aberrations, direct sequencing of PLC beta 3 cDNAs from two affected persons from two different MEN 1 families was performed, but no MEN 1-specific abnormalities were revealed. Several common nucleotide sequence polymorphisms were detected in these cDNAs, proving that both alleles of the PLC beta 3 gene were expressed and analyzed. In conclusion, these results exclude the PLC beta 3 gene as a candidate gene for MEN 1. 相似文献