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51.
Wei Yu Zishen Wang Xiaoxu Zhao Junyong Wang Tun Seng Herng Teng Ma Zhiyu Zhu Jun Ding Goki Eda Stephen J. Pennycook Yuan Ping Feng Kian Ping Loh 《Advanced functional materials》2020,30(31)
Chemical exfoliation has been used for the fast and large‐scale production of 2D nanosheets from graphene and transition metal dichalcogenides; however, it is rarely used for domain engineering of exfoliated nanosheets. Herein, it is found that the use of large sized molecular intercalants during electrochemical intercalation induce atomic row dislocation and parallel mirror twin boundaries (MTBs) on an otherwise pristine rhenium disulfide (ReS2) crystal, such that the exfoliated flakes possess a parallel, multi‐domain structure. These domains can be distinguished under a polarized microscope owing to the intrinsic in‐plane optical dichroic properties of ReS2, thereby affording a way to track the number of domains introduced versus the size of the molecular intercalant during electrochemical exfoliation. Ferromagnetism is detected on the intercalated sample using large sized molecular intercalants. Density function theory suggests that these may be due to the coupled effects of lattice strain and S vacancies in the MTBs. 相似文献
52.
Indoor inhalation intake fractions of fine particulate matter: review of influencing factors
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N. Hodas M. Loh H.‐M. Shin D. Li D. Bennett T. E. McKone O. Jolliet C. J. Weschler M. Jantunen P. Fantke 《Indoor air》2016,26(6):836-856
Exposure to fine particulate matter (PM2.5) is a major contributor to the global human disease burden. The indoor environment is of particular importance when considering the health effects associated with PM2.5 exposures because people spend the majority of their time indoors and PM2.5 exposures per unit mass emitted indoors are two to three orders of magnitude larger than exposures to outdoor emissions. Variability in indoor PM2.5 intake fraction (iFin,total), which is defined as the integrated cumulative intake of PM2.5 per unit of emission, is driven by a combination of building‐specific, human‐specific, and pollutant‐specific factors. Due to a limited availability of data characterizing these factors, however, indoor emissions and intake of PM2.5 are not commonly considered when evaluating the environmental performance of product life cycles. With the aim of addressing this barrier, a literature review was conducted and data characterizing factors influencing iFin,total were compiled. In addition to providing data for the calculation of iFin,total in various indoor environments and for a range of geographic regions, this paper discusses remaining limitations to the incorporation of PM2.5‐derived health impacts into life cycle assessments and makes recommendations regarding future research. 相似文献
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The exchanged hypercube 总被引:2,自引:0,他引:2
Loh P.K.K. Hsu W.J. Pan Y. 《Parallel and Distributed Systems, IEEE Transactions on》2005,16(9):866-874
This paper presents the exchanged hypercube, a new interconnection network obtained by systematically removing links from a binary hypercube. It maintains several desirable properties of the binary hypercube yet with reduced interconnection complexity. We also introduce the extended binomial tree, a spanning tree of the exchanged hypercube that preserves many desirable properties of the original binomial tree. A fault-tolerant routing strategy is also proposed for the exchanged hypercube. 相似文献
56.
Yong Yang Fuh J.Y.H. Han Tong Loh Yoke San Wong 《Automation Science and Engineering, IEEE Transactions on》2005,2(3):276-284
The factors that generally affect the slicing error in layered manufacturing (LM) processes are first analyzed, and issues pertaining to the current methods to deal with the slicing error are discussed in this paper. A method based on a recently developed and implemented orthogonal LM system to reduce the overall slicing error is presented. In this method, the flat region is separated from the stereolithography (STL) model and different processing methods are applied to the different areas in the part geometry. In addition, the mathematical model for calculating the slicing error is derived and an approach based on a genetic algorithm has been developed to optimize the build orientation in terms of minimizing the slicing error. Case studies are given to demonstrate the effectiveness and efficiency of the method. Note to Practitioner-The staircase effect has been the major concern for industry to widely adopt rapid prototyping technologies. It will not only worsen the surface quality but also create errors on the parts built. This paper introduces a novel approach to minimizing staircase errors based on a multidirectional deposition approach. A mathematical method combined with a generic algorithm is used to minimize the slicing errors. From the case study given, the approach has been proven to be effective in minimizing staircase errors and thus improving the rapid prototyping (RP) built part quality. 相似文献
57.
KP Papadopoulos JH Garvin M Fetell LT Vahdat TJ Garrett DG Savage C Balmaceda J Bruce M Sisti S Isaacson R De LaPaz R Hawks E Bagiella KH Antman CS Hesdorffer 《Canadian Metallurgical Quarterly》1998,22(7):661-667
The prognosis in patients with primary brain tumors treated with surgery, radiotherapy and conventional chemotherapy remains poor. To improve outcome, combination high-dose chemotherapy (HDC) has been explored in children, but rarely in adults. This study was performed to determine the tolerability of three-drug combination high-dose thiotepa (T) and etoposide (E)-based regimens in pediatric and adult patients with high-risk or recurrent primary brain tumors. Thirty-one patients (13 children and 18 adults) with brain tumors were treated with high-dose chemotherapy: 19 with BCNU (B) and TE (BTE regimen), and 12 with carboplatin (C) and TE (CTE regimen). Patients received growth factors and hematopoietic support with marrow (n = 15), peripheral blood progenitor cells (PBPC) (n = 11) or both (n = 5). The 100 day toxic mortality rate was 3% (1/31). Grade III/IV toxicities included mucositis (58%), hepatitis (39%) and diarrhea (42%). Five patients had seizures and two had transient encephalopathy (23%). All patients had neutropenic fever and all pediatric patients required hyperalimentation. Median time to engraftment with absolute neutrophil count (ANC) >0.5 x 10(9)/l was 11 days (range 8-37 days). Time to ANC engraftment was significantly longer (P = 0.0001) in patients receiving marrow (median 14 days, range 10-37) than for PBPC (median 9.5 days, range 8-10). Platelet engraftment >50 x 10(9)/l was 24 days (range 14-53 days) in children. In adults, platelet engraftment >20 x 10(9)/l was 12 days (range 9-65 days). In 11 patients supported with PBPC, there was a significant inverse correlation between CD34+ dose and days to ANC (rho = -0.87, P = 0.009) and platelet engraftment (rho = -0.85, P = 0.005), with CD34+ dose predicting time to engraftment following HDC. Overall, 30% of evaluable patients (7/24) had a complete response (CR) (n = 3) or partial response (PR) (n = 4). Median time to tumor progression (TTP) was 7 months, with an overall median survival of 12 months. These TE-based BCNU or carboplatin three-drug combination HDC regimens are safe and tolerable with promising response rates in both children and older adults. 相似文献
58.
ML Loh TW McLean JD Buckley W Howells DG Gilliland FO Smith 《Canadian Metallurgical Quarterly》1998,22(5):461-464
The percutaneous cardiopulmonary support system (PCPS) was used in a 64-year-old woman with cardiogenic shock due to sustained ventricular fibrillation (Vf) caused by severe aortic stenosis and regurgitation. The Vf attack was resistant to cardioversion and adrenaline for lack of left ventricular support by PCPS. She was transported to the operation theater with PCPS in situ and emergency aortic valve replacement was performed. Although preoperative cardiac resuscitation time was long (35 minutes), she was discharged from the hospital on foot without any neurological complications on 84th postoperative day. Because PCPS does not decrease left ventricular systolic stress in poorly contracting dilated heart, early surgical treatment is needed in patients with severely damaged heart. 相似文献
59.
Our objective was: (1) to determine the appropriate dose of new ultrasmall superparamagnetic iron oxide particles for magnetic resonance angiography (MRA). This agent comprised of a single iron oxide crystal stabilized with a carbohydrate-polyethylene glycol coat (PEG-Ferron/NC 100150 injection); (2) to determine the proper flip angle for PEG-Ferron-enhanced 3 D time-of-flight (TOF) MRA sequence; and (3) to compare the enhancement of peripheral vessels following PEG-Ferron and GdDTPA-BMA. MRA parameters were: TR/TE = 50/2.1 ms, NEX = 1, FOV = 30 x 30 x 1.8 cm, and matrix = 256 x 128 x 64. In anesthetized beagle dogs (n = 10), the effects of PEG-Ferron and GdDTPA-BMA on regional signal were monitored for 45 min and compared. The lowest dose of PEG-Ferron (0.05 mmol/kg) produced the best enhancement of primary, secondary and tertiary vessels. The flip angle 60 degrees provided better enhancement than 20 degrees on contrast enhanced images. Unlike GdDTPA-BMA, PEG-Ferron allowed prolonged delineation (> 45 min) of the pelvis and lower extremities circulation. PEG-Ferron provided greater Contrast-to-noise ratio CNR (80.2 +/- 6.2, P < 0.05) than GdDTPA-BMA (63.5 +/- 2.5). It may be possible for blood pool contrast-enhanced 3 D TOF MRA to provide valuable information for visualization of vascular tree including guiding interventions. 相似文献
60.
The rDNA minichromosomes of Tetrahymena thermophila and Tetrahymena pyriformis share a high degree of sequence similarity and structural organization. The T.thermophila 5' non-transcribed spacer (5' NTS) is sufficient for replication and contains three repeated sequence elements that are conserved in T.pyriformis , including type I elements, the only known determinant for replication control. To assess the role of conserved sequences in replication control, structural and functional studies were performed on T.pyriformis rDNA. Similar to T.thermophila , replication initiates exclusively in the 5' NTS, localizing to a 900 bp segment. Elongating replication forks arrest transiently at one site which bears strong similarity to a tripartite sequence element present at fork arrest sites in T.thermophila rDNA. An in vitro type I element binding activity indistinguishable from the T.thermophila protein, ssA-TIBF, was detected in T.pyriformis extracts. The respective TIBF proteins bind with comparable affinity to type I elements from both species, suggesting that in vivo recognition could cross species boundaries. Despite these similarities, the T.pyriformis 5' NTS failed to support replication in transformed T.thermophila cells, suggesting a more complex genetic organization than previously realized. 相似文献