Molecular dynamics (MD) was used to build a simulation model for skiving single crystal silicon (SCS) with different tool radius. Through the analysis of phase change, instantaneous atomic position, ...temperature, Wigner-Seitz defects, stress and other variables, and the mechanical state distribution of SCS during processing is studied. The results show that the amorphous phase transition process occurs in the process of skiving SCS with different tool radii, the difference is that amorphous atoms use chips during sharp corner cutting. The form is removed, and the amorphous atoms in the rounded tool are further compressed directly under the tool, causing subsurface damage. The removal mechanism of sharp corner cutter chips is shear, and the removal mechanism of round corner cutter chips is shear and extrusion. And as the radius of the tool increases, the number of compressed atoms below the tool increases directly, resulting in a decrease in the quality of the processed surface.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The scale of English language education in China is astounding, but recent research has shown that the latest national English education policy for Chinese schools has not been implemented ...successfully due to various reasons. One reason given for the lack of success is the impracticability of the top-down policy itself excluding teachers' involvement and neglecting the contextual constraints. Building on the theoretical framework of multi-levelled actors in language planning and language policy, and drawing on some key concepts in relation to power in Critical Language Policy research, this paper explores how a national English language curriculum that emphasizes the international standards and norms in curriculum design has been enacted, ineffectively, by the key stakeholders through analysing the specific roles of three groups of key stakeholders involved in the English as a foreign language curriculum policy implementation.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Summary Background Plasmodium falciparum sporozite (PfSPZ) Vaccine is a metabolically active, non-replicating, whole malaria sporozoite vaccine that has been reported to be safe and protective ...against P falciparum controlled human malaria infection in malaria-naive individuals. We aimed to assess the safety and protective efficacy of PfSPZ Vaccine against naturally acquired P falciparum in malaria-experienced adults in Mali. Methods After an open-label dose-escalation study in a pilot safety cohort, we did a double-blind, randomised, placebo-controlled trial based in Donéguébougou and surrounding villages in Mali. We recruited 18–35-year-old healthy adults who were randomly assigned (1:1) in a double-blind manner, with stratification by village and block randomisation, to receive either five doses of 2·7 × 105 PfSPZ or normal saline at days 0, 28, 56, 84, and 140 during the dry season (January to July inclusive). Participants and investigators were masked to group assignments, which were unmasked at the final study visit, 6 months after receipt of the last vaccination. Participants received combined artemether and lumefantrine (four tablets, each containing 20 mg artemether and 120 mg lumefantrine, given twice per day over 3 days for a total of six doses) to eliminate P falciparum before the first and last vaccinations. We collected blood smears every 2 weeks and during any illness for 24 weeks after the fifth vaccination. The primary outcome was the safety and tolerability of the vaccine, assessed as local and systemic reactogenicity and adverse events. The sample size was calculated for the exploratory efficacy endpoint of time to first P falciparum infection beginning 28 days after the fifth vaccination. The safety analysis included all participants who received at least one dose of investigational product, whereas the efficacy analyses included only participants who received all five vaccinations. This trial is registered at ClinicalTrials.gov , number NCT01988636. Findings Between Jan 18 and Feb 24, 2014, we enrolled 93 participants into the main study cohort with 46 participants assigned PfSPZ Vaccine and 47 assigned placebo, all of whom were evaluable for safety. We detected no significant differences in local or systemic adverse events or laboratory abnormalities between the PfSPZ Vaccine and placebo groups, and only grade 1 (mild) local or systemic adverse events occurred in both groups. The most common solicited systemic adverse event in the vaccine and placebo groups was headache (three 7% people in the vaccine group vs four 9% in the placebo group) followed by fatigue (one 2% person in the placebo group), fever (one 2% person in the placebo group), and myalgia (one 2% person in each group). The exploratory efficacy analysis included 41 participants from the vaccine group and 40 from the placebo group. Of these participants, 37 (93%) from the placebo group and 27 (66%) from the vaccine group developed P falciparum infection. The hazard ratio for vaccine efficacy was 0·517 (95% CI 0·313–0·856) by time-to-infection analysis (log-rank p=0·01), and 0·712 (0·528–0·918) by proportional analysis (p=0·006). Interpretation PfSPZ Vaccine was well tolerated and safe. PfSPZ Vaccine showed significant protection in African adults against P falciparum infection throughout an entire malaria season. Funding US National Institutes of Health Intramural Research Program, Sanaria.
The overall purpose of this study was to explore the identified language challenges and supports for writing in Standard Australian English for secondary English as an Additional Language or Dialect ...(EAL/D) students. An initial review of the academic literature revealed that this research topic has not been extensively researched in the Australian context. For this reason, this research project involved a systematic scoping study of the academic literature, based on the framework of Arksey and O'Malley (2005) to determine findings to date. The 35 articles examined revealed a range of themes that either challenged or supported the writing process for Australian EAL/D secondary students. Key challenges that EALD learners in secondary contexts face when developing Standard Australian English (SAE) writing skills revolve around policy mandates from curriculum and assessment authorities, de-facto policy as realised through EAL and mainstream curriculum, teachers' attitudes, knowledge and beliefs, including notions of deficit, and pre-service teacher preparation. What was found to support EAL/D students were different pedagogical approaches which are cognizant of students' cultural knowledge, experiences and linguistic resources, as well as genre-based approaches incorporating Systemic Functional Linguistics and a teaching and learning cycle and technology. Given that some of the studies were relatively small which impacts generalizability, further research in relation to the topics under study would be encouraged, particularly as to what supports a wider range of EAL/D students.
The gas diffusion layer (GDL), as the main mass transfer carrier in a hydrogen fuel cell, transports fuel and discharges water, the only by-product of the electrochemical reaction. The dispersion ...process of water in the pore will hinder the diffusion of gas, thus reducing the concentration of fuel gas at the catalytic site, resulting in the decrease of the electrochemical reaction rate. In this paper, the effect of wettability in the GDL hole on the water transport process is studied. When the pore wall is hydrophilic, the liquid phase is affected by the gas phase eddy current velocity field, and the particles at the center advance to the edge, forming a liquid phase interface with a thin center and thick edge. With the increase of the wall contact angle, the curvature of the three-phase interface increases, the wall adhesion decreases, and the liquid phase is more likely to be discharged. When the contact angle is 130°, the liquid phase almost does not shift in the hole with a radius of 5 μm. With the increase of the radius or inlet pressure difference, the liquid phase is discharged gradually, and the discharge rate of the liquid phase is only related to the wettability of the wall.
This article draws on data collected during case studies involving six undergraduate international students. It uses the academic literacies framework to examine how international students ...(re)negotiate their student identities. Based on the concept that Australian university classrooms are global educational contact zones, the study reinforces the urgent need to shift from existing narratives which focus on international students' perceived language and literacy deficits. Participants demonstrated positive student identities by successfully mediating disciplinary requirements. However, their transition was hindered due to insufficient opportunities for meaningful classroom interactions and lack of academic instruction and feedback. The findings suggest teachers are in the best position to address this gap through classroom pedagogies which accommodate learners from diverse backgrounds and facilitate inclusive learning environments. Author abstract
Based on the density functional theory (DFT), the electronic properties of O-doped pure and sulfur vacancy-defect monolayer WS₂ are investigated by using the first-principles method. For the O-doped ...pure monolayer WS₂, four sizes (2 × 2 × 1, 3 × 3 × 1, 4 × 4 × 1 and 5 × 5 × 1) of supercell are discussed to probe the effects of O doping concentration on the electronic structure. For the 2 × 2 × 1 supercell with 12.5% O doping concentration, the band gap of O-doped pure WS₂ is reduced by 8.9% displaying an indirect band gap. The band gaps in 3 × 3 × 1 and 4 × 4 × 1 supercells are both opened to some extent, respectively, for 5.55% and 3.13% O doping concentrations, while the band gap in 5 × 5 × 1 supercell with 2.0% O doping concentration is quite close to that of the pure monolayer WS₂. Then, two typical point defects, including sulfur single-vacancy (V
) and sulfur divacancy (V
), are introduced to probe the influences of O doping on the electronic properties of WS₂ monolayers. The observations from DFT calculations show that O doping can broaden the band gap of monolayer WS₂ with V
defect to a certain degree, but weaken the band gap of monolayer WS₂ with V
defect. Doping O element into either pure or sulfur vacancy-defect monolayer WS₂ cannot change their band gaps significantly, however, it still can be regarded as a potential method to slightly tune the electronic properties of monolayer WS₂.
Surface landscapes have vague impact on the mechanical properties of graphene. In this paper, single-layered graphene sheets (SLGS) with regular wrinkles were first constructed by applying shear ...deformation using molecular dynamics (MD) simulations and then indented to extract their mechanical properties. The influence of the boundary condition of SLGS were considered. The wrinkle features and wrinkle formation processes of SLGS were found to be significantly related to the boundary conditions as well as the applied shear displacement and velocity. The wrinkling amplitude and degree of wrinkling increased with the increase in the applied shear displacements, and the trends of wrinkling wavelengths changed with the different boundary conditions. With the fixed boundary condition, the degree of graphene wrinkling was only affected when the velocity was greater than a certain value. The effect of wrinkles on the mechanical characterization of SLGS by atomic force microscopy (AFM) nanoindentation was finally investigated. The regular surface wrinkling of SLGS was found to weaken the Young's modulus of graphene. The Young's modulus of graphene deteriorates with the increase in the degree of regular wrinkling.
Purpose - The purpose of this scoping review was to examine research studies relating to autistic students in learning English as an Additional Language (EAL) to outline potential research agendas ...and to inform EAL educators of current related issues. Methodology - PRISMA-ScR protocol outlined by Tricco et al. (2018) was followed when selecting the relevant studies published before July 2020 from six prominent databases: Education database, ERIC; Linguistics database, PsycINFO; SAGE, and Scopus. In addition, a hand search of Google Scholars was conducted. Inclusion and exclusion criteria were applied to screen the identified data. Findings - From the evidence provided in the eighteen studies identified, the researcher found that current autism research in EAL focused more on teaching strategies and much less on autistic individuals’ EAL learning processes. The 118 autistic participants in the identified studies displayed highly diverse characteristics, which may explain why the case study was the dominant research approach. They were reported by the identified studies to have strong microlinguistic skills (phonology, morphology, syntax-related) but were weak in macro-linguistic skills (e.g., reading comprehension). The researcher noted that some learning behaviours of autistic students have been reported in addition to some teaching strategies perceived effective for teaching autistic EAL learners such as utilisation of technology and a visual approach. Significance - While there is an increasing number of autistic individuals learning EAL, research on autistic students learning EAL and on teaching autistic students EAL has been limited to date. This present study is the first scoping review to investigate existing relevant studies. Despite calling for further investigation into the teaching and learning of autistic students in EAL that involve the perspectives of parents of non-autistic peers, and of the autistic students themselves, interactive patterns of teaching and learning of autistic individuals in EAL classrooms remains an area for further research in the future.
: A radiation-attenuated
(Pf) sporozoite (SPZ) malaria vaccine, PfSPZ Vaccine, protected 6 of 6 subjects (100%) against homologous Pf (same strain as in the vaccine) controlled human malaria ...infection (CHMI) 3 weeks after 5 doses administered intravenously. The next step was to assess protective efficacy against heterologous Pf (different from Pf in the vaccine), after fewer doses, and at 24 weeks.
: The trial assessed tolerability, safety, immunogenicity, and protective efficacy of direct venous inoculation (DVI) of 3 or 5 doses of PfSPZ Vaccine in non-immune subjects.
: Three weeks after final immunization, 5 doses of 2.7 × 10
PfSPZ protected 12 of 13 recipients (92.3% 95% CI: 48.0, 99.8) against homologous CHMI and 4 of 5 (80.0% 10.4, 99.5) against heterologous CHMI; 3 doses of 4.5 × 10
PfSPZ protected 13 of 15 (86.7% 35.9, 98.3) against homologous CHMI. Twenty-four weeks after final immunization, the 5-dose regimen protected 7 of 10 (70.0% 17.3, 93.3) against homologous and 1 of 10 (10.0% -35.8, 45.6) against heterologous CHMI; the 3-dose regimen protected 8 of 14 (57.1% 21.5, 76.6) against homologous CHMI. All 22 controls developed Pf parasitemia. PfSPZ Vaccine was well tolerated, safe, and easy to administer. No antibody or T cell responses correlated with protection.
: We have demonstrated for the first time to our knowledge that PfSPZ Vaccine can protect against a 3-week heterologous CHMI in a limited group of malaria-naive adult subjects. A 3-dose regimen protected against both 3-week and 24-week homologous CHMI (87% and 57%, respectively) in this population. These results provide a foundation for developing an optimized immunization regimen for preventing malaria.
: ClinicalTrials.gov NCT02215707.
: Support was provided through the US Army Medical Research and Development Command, Military Infectious Diseases Research Program, and the Naval Medical Research Center's Advanced Medical Development Program.
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