Nanocrystalline diamond microstructures from Ar/H2/CH4-plasma chemical vapour deposition

[[abstract]]The incorporation of H2 into Ar plasma was observed to markedly alter the microstructure of diamond films. The addition of a small percentage of H2 (<1.5%) into the Ar plasma leads to the presence of stacking faults in plate-like diamond grains, the incorporation of 75% H2 induces the formation of the diamond polymorph (8H). Optical emission spectroscopy indicated that addition of H2 into the Ar/CH4 plasma decreased the CH/C2 ratio and increased the proportion of atomic hydrogen. The small proportion of atomic hydrogen in 1.5%H2–Ar plasma can only induce the formation of (111) stacking faults, resulting in scarcely distributed plate-like diamond grains. The large proportion of atomic hydrogen in 75%H2–Ar plasma causes the rapid growth of diamond grains, leading to the formation of polymorphs of diamond lattices. The tuning on the microstructure of the UNCD films by incorporating either small or large amounts of H2 in Ar-plasma can be attributed to the interaction of H-species with the grain boundary hydrocarbons. Such a capability opens up the potential for applications of UNCD films. Despite the complication in granular structure resulted from the CH4/(Ar–H2) plasma chemical vapour deposition, the formation of microstructures can be explained by the same pathway, the competition of the processes (i) formation of a hydrocarbon passivation layer and the re-activation of the hydrocarbon layer and (ii) secondary nucleation and the enlargement of diamond grains.[[incitationindex]]SCI[[booktype]]電子

Review Classification Using Semantic Features and Run-Time Weighting

PACLIC 23 / City University of Hong Kong / 3-5 December 200

The potential application of ultra-nanocrystalline diamond films for heavy ion irradiation detection

[[abstract]]The potential of utilizing the ultra-nanocrystalline (UNCD) films for detecting the Au-ion irradiation was investigated. When the fluence for Au-ion irradiation is lower than the critical value (fc = 5.0 × 1012 ions/cm2) the turn-on field for electron field emission (EFE) process of the UNCD films decreased systematically with the increase in fluence that is correlated with the increase in sp2-bonded phase (π*-band in EELS) due to the Au-ion irradiation. The EFE properties changed irregularly, when the fluence for Au-ion irradiation exceeds this critical value. The transmission electron microscopic microstructural examinations, in conjunction with EELS spectroscopic studies, reveal that the structural change preferentially occurred in the diamond-to-Si interface for the samples experienced over critical fluence of Au-ion irradiation, viz. the crystalline SiC phase was induced in the interfacial region and the thickness of the interface decreased. These observations implied that the UNCD films could be used as irradiation detectors when the fluence for Au-ion irradiation does not exceed such a critical value.[[incitationindex]]SCI[[booktype]]電子

A rare, highly aggressive primitive neuroectodermal tumor of the kidney: Case report and literature review

AbstractWe report a case of a 14-year-old boy who initially suffered from a sudden onset of abdominal pain for 2 weeks with a protrusive soft mass over the left upper abdomen. No obvious symptomatic symptoms or body weight loss were observed. However, early lung metastasis was detected after an initial computed tomographic examination. Even after we performed salvage en bloc resection of the huge retroperitoneal tumor after primary neoadjuvant chemotherapy, the final outcome was still poor. A diagnosis according to radiologic findings was uncharacteristic. Finally, a pathologic diagnosis based on histologic and immunohistochemical results revealed a rare renal peripheral primitive neuroectodermal tumor

Impact of Large Language Models on Generating Software Specifications

Software specifications are essential for ensuring the reliability of software systems. Existing specification extraction approaches, however, suffer from limited generalizability and require manual efforts. We study the effectiveness of Large Language Models (LLMs) in generating software specifications from software documentation, utilizing Few-Shot Learning (FSL) to enable LLMs to generalize from a small number of examples. We compare the performance of LLMs with FSL to that of state-of-the-art specification extraction techniques and study the impact of prompt construction strategies on LLM performance. In addition, we conduct a comprehensive analysis of their symptoms and root causes of the failures to understand the pros and cons of LLMs and existing approaches. We also compare 11 LLMs' performance, cost, and response time for generating software specifications. Our findings include that (1) the best performing LLM outperforms existing approaches by 9.1--13.7% with a few similar examples, (2) the two dominant root causes combined (ineffective prompts and missing domain knowledge) result in 57--60% of LLM failures, and (3) most of the 11 LLMs achieve better or comparable performance compared to traditional techniques. Our study offers valuable insights for future research to improve specification generation

The 3D-tomography of the nano-clusters formed by Fe-coating and annealing of diamond films for enhancing their surface electron field emitters

[[abstract]]The Fe-coating and H2-annealed processes markedly increased the conductivity and enhanced the surface electron field emission (s-EFE) properties for the diamondfilms. The enhancement on the s-EFE properties for the diamondfilms is presumably owing to the formation of nano-graphite clusters on the surface of the films via the Fe-to-diamond interaction. However, the extent of enhancement varied with the granular structure of the diamondfilms. For the microcrystalline (MCD)films, the s-EFE process can be turned on at (E0)MCD = 1.9 V/μm, achieving a large s-EFE current density of (Je)MCD = 315 μA/cm2 at an applied field of 8.8 V/μm. These s-EFE properties are markedly better than those for Fe-coated/annealed ultrananocrystalline diamond(UNCD)films with (E0)UNCD = 2.0 V/μm and (Je)UNCD = 120 μA/cm2. The transmission electron microscopy showed that the nano-graphite clusters formed an interconnected network for MCDfilms that facilitated the electron transport more markedly, as compared with the isolated nano-graphitic clusters formed at the surface of the UNCDfilms. Therefore, the Fe-coating/annealing processes improved the s-EFE properties for the MCDfilms more markedly than that for the UNCDfilms. The understanding on the distribution of the nano-clusters is of critical importance in elucidating the authentic factor that influences the s-EFE properties of the diamondfilms. Such an understanding is possible only through the 3D-tomographic investigations.[[journaltype]]國外[[ispeerreviewed]]Y[[booktype]]電子版[[countrycodes]]US

Second-trimester Maternal Serum Quadruple Test for Down Syndrome Screening: A Taiwanese Population-based Study

SummaryObjectiveTo assess the usefulness of quadruple test screening for Down syndrome in Taiwan.Materials and MethodsMaternal serum concentrations of a-fetoprotein, human chorionic gonadotropin, unconjugated estriol, and inhibin A were measured in 21,481 pregnant women from 15 to 20 weeks of gestation.ResultsOf the 21,481 women, 977 returned values greater than the high-risk cut-off value (1 in 270). Most of these women (86.2%) decided to have an invasive procedure for genetic diagnosis. Nine cases of Down syndrome and 19 cases of other chromosomal anomalies were detected prenatally. Two children with Down syndrome were diagnosed after delivery even though a low estimated risk was determined following the quadruple test. The detection rate was 81.8% (nine out of 11 cases), with a 4.4% false-positive rate. The median multiple of the median value for a-fetoprotein, human chorionic gonadotropin, unconjugated estriol and inhibin A were 0.87, 2.34, 0.77 and 2.16, respectively, in affected cases.ConclusionThis is the first study of the quadruple test for Down syndrome in a Chinese population. Our findings suggested that the second-trimester quadruple test provides an effective screening tool for Down syndrome in Taiwan