Peculiar Structural Phase of a Single-Atom-Thick Layer of Antimony.

Using molecular beam epitaxy, a new structural phase of a single atom thick antimony layer has been synthesized on the W(110) surface. Scanning tunneling microscopy measurements reveal an atomically resolved structure with a perfectly flat surface and unusually large unit cell. The structure forms a well-ordered continuous film with a lateral size in the range of several millimeters, as revealed by low energy electron microscopy and diffraction experiments. The results of density functional theory calculations confirm the formation of a new phase of single-atom-thick antimony film without the buckling characteristic for the known phases of antimonene. The presented results demonstrate a substrate-tuned approach in the preparation of new structural phases of 2D materials.

Bromine Adsorption and Thermal Stability on Rh(111): A Combined XPS, LEED and DFT Study.

This study addresses a fundamental question in surface science: the adsorption of halogens on metal surfaces. Using synchrotron radiation-based high-resolution X-ray photoelectron spectroscopy (XPS), temperature-programmed XPS, low-energy electron diffraction (LEED) and density functional theory (DFT) calculations, we investigated the adsorption and thermal stability of bromine on Rh(111) in detail. The adsorption of elemental bromine on Rh(111) at 170 K was followed in situ by XPS in the Br 3d region, revealing two individual, coverage-dependent species, which we assign to fcc hollow- and bridge-bound atomic bromine. In addition, we find a significant shift in binding energy upon increasing coverage due to adsorbate-adsorbate interactions. Subsequent heating shows a high thermal stability of bromine on Rh(111) up to above 1000 K, indicating strong covalent bonding. To complement the XPS data, LEED was used to study the long-range order of bromine on Rh(111): we observe a (√3×√3)R30° structure for low coverages (≤0.33 ML) and a star-shaped compression structure for higher coverages (0.33-0.43 ML). Combining LEED and DFT calculations, we were able to visualize bromine adsorption on Rh(111) in real space for varying coverages.

Stability of Graphene/Intercalated Oxygen/Ru(0001) as Studied by Thermal Desorption of CO and CO2 Molecules.

Formation of graphene on Ru(0001) by exposure to ethylene and subsequent annealing has been studied by low-energy electron diffraction, X-ray photoelectron spectroscopy, and ultraviolet photoelectron spectroscopy. The stability of graphene/intercalated oxygen/Ru(0001) has been investigated by temperature programmed desorption spectroscopy. Desorption of CO and CO2 was observed upon heating the samples to temperatures above 700 K. It was found that the graphene layer was partly intact after the desorption run and that the intercalated oxygen was removed. It was concluded that the oxygen-intercalated graphene layer was stable up to temperatures of about 700 K.

Broad background in electron diffraction of 2D materials as a signature of their superior quality.

An unusually broad bell-shaped component (BSC) has been previously observed in surface electron diffraction on different types of 2D systems. It was suggested to be an indicator of uniformity of epitaxial graphene (Gr) and hexagonal boron nitride (hBN). In the current study we use low-energy electron microscopy and micro-diffraction to directly relate the BSC to the crystal quality of the diffracting 2D material. Specially designed lateral heterostructures were used to map the spatial evolution of the diffraction profile across different 2D materials, namely pure hBN, BCN alloy and pure Gr, where the alloy region exhibits deteriorated structural coherency. The presented results show that the BSC intensity has a minimum in the alloyed region, consequently showing that BSC is sensitive to the lateral domain size and homogeneity of the material under examination. This is further confirmed by the presence of a larger number of sharp moiré spots when the BSC is most pronounced in the pure hBN and Gr regions. Consequently, it is proposed that the BSC can be used as a diagnostic tool for determining the quality of the 2D materials.

Oxygen intercalation in PVD graphene grown on copper substrates: A decoupling approach.

We investigate the intercalation process of oxygen in-between a PVD-grown graphene layer and different copper substrates as a methodology for reducing the substrate-layer interaction. This growth method leads to an extended defect-free graphene layer that strongly couples with the substrate. We have found, by means of X-ray photoelectron spectroscopy, that after oxygen exposure at different temperatures, ranging from 280 °C to 550 °C, oxygen intercalates at the interface of graphene grown on Cu foil at an optimal temperature of 500 °C. The low energy electron diffraction technique confirms the adsorption of an atomic oxygen adlayer on top of the Cu surface and below graphene after oxygen exposure at elevated temperature, but no oxidation of the substrate is induced. The emergence of the 2D Raman peak, quenched by the large interaction with the substrate, reveals that the intercalation process induces a structural undoing. As suggested by atomic force microscopy, the oxygen intercalation does not change significantly the surface morphology. Moreover, theoretical simulations provide further insights into the electronic and structural undoing process. This protocol opens the door to an efficient methodology to weaken the graphene-substrate interaction for a more efficient transfer to arbitrary surfaces.

A new interpretation of the √7×√7 R19.1° structure for P adsorbed on a Ni(111) surface.

We have studied P adsorption on Ni(111), a system which shows complex adsorbate structures. We determined the phase diagram of the surface P adsorbed on Ni(111). At low coverage, amorphous P was observed. At temperatures between 373 and 673 K and coverages above 0.1 monolayer, we found a 7 × 7   R 19.1 ∘ structure, but above 673 K, other complex structures were created. These structures seemed to correlate with each other and we reinterpret a 7 × 7   R 19.1 ∘ structure of P adsorbed on Ni(111) based on the similarities of these surface structures. The new rectangular structure for the 7 × 7   19.1 ∘ is discussed in relation to the Ni2P local structure.

Magnetic Iron Oxide Nanowires Formed by Reactive Dewetting.

The growth and reactive dewetting of ultrathin films of iron oxides supported on Re(0001) surfaces have been imaged in situ in real time. Initial growth forms a nonmagnetic stable FeO (wüstite like) layer in a commensurate network upon which high aspect ratio nanowires of several microns in length but less than 40 nm in width can be fabricated. The nanowires are closely aligned with the substrate crystallography and imaging by X-ray magnetic circular dichroism shows that each contain a single magnetic domain. The driving force for dewetting appears to be the minimization of strain energy of the Fe3O4 crystallites and follows the Tersoff and Tromp model in which strain is minimized at constant height by extending in one epitaxially matched direction. Such wires are promising in spintronic applications and we predict that the growth will also occur on other hexagonal substrates.

Barriers and incentives for sustainable urban development: An analysis of the adoption of LEED-ND projects.

The adoption rate for Leadership in Energy and Environmental Design - Neighborhood Development (LEED-ND) projects has varied considerably across the United States. Local governments and developers face variation in the incentives and barriers while implementing LEED-ND projects across four key dimensions - economic, policy, public awareness, and organizational. This paper investigated the drivers of variation using a mixed-methods approach including a two-stage Heckman model, a survey of Texas subdivision developers and interviews with local planning officials. Results indicate that initial public funding may lead to more LEED-ND projects being completed, but with a diminishing return as these projects become established within the region. Support for local programs including tax abatement, public-private partnerships, and other incentives were also demonstrated to help facilitate LEED-ND project adoption. Overall this paper underscored the important role, especially early on, the public sector and local governments play in initiating local LEED-ND projects to inform and motivate the land development industry.

Lisbon Emoji and Emoticon Database (LEED): Norms for emoji and emoticons in seven evaluative dimensions.

The use of emoticons and emoji is increasingly popular across a variety of new platforms of online communication. They have also become popular as stimulus materials in scientific research. However, the assumption that emoji/emoticon users' interpretations always correspond to the developers'/researchers' intended meanings might be misleading. This article presents subjective norms of emoji and emoticons provided by everyday users. The Lisbon Emoji and Emoticon Database (LEED) comprises 238 stimuli: 85 emoticons and 153 emoji (collected from iOS, Android, Facebook, and Emojipedia). The sample included 505 Portuguese participants recruited online. Each participant evaluated a random subset of 20 stimuli for seven dimensions: aesthetic appeal, familiarity, visual complexity, concreteness, valence, arousal, and meaningfulness. Participants were additionally asked to attribute a meaning to each stimulus. The norms obtained include quantitative descriptive results (means, standard deviations, and confidence intervals) and a meaning analysis for each stimulus. We also examined the correlations between the dimensions and tested for differences between emoticons and emoji, as well as between the two major operating systems-Android and iOS. The LEED constitutes a readily available normative database (available at www.osf.io/nua4x ) with potential applications to different research domains.

Strategic Behavior in Certifying Green Buildings: An Inquiry of the Non-building Performance Value.

This study determines the magnitude of the market signaling effect arising from Leadership in Energy and Environmental Design certification for green buildings and explores the mechanisms behind the signaling effect. Previous studies have shown that signaling or marketability plays an important role in the pursuit for Leadership in Energy and Environmental Design and equivalent green-building certification. By analyzing all new construction projects receiving Leadership in Energy and Environmental Design certification from 2000 to 2012 in the US, this study estimates the relative importance of 'green' signaling. This broad perspective using project-level data enables an analysis of some drivers of signaling and the pursuit of marketing benefits. The roles of local competition and market conditions, as well as municipal regulations are examined, especially as they differ between types of building owners (e.g., for-profit firms, governments, nonprofits). The results indicate that the non-building performance value-value captured by Leadership in Energy and Environmental Design signals above and beyond the specific building attributes that Leadership in Energy and Environmental Design certifies-dominates the attainment of Leadership in Energy and Environmental Design scores around certification tier thresholds. Further, strong evidence of spatial clustering of this non-building performance value for some owner types indicates that for-profit owners may be more responsive to local competition than non-profit owners. Local legislative mandates predict greater signaling intensity by government-owned buildings, as expected, but for-profit-owned projects tend to signal less, even after controls for local conditions. The results highlight the importance of local conditions, including peer effects and regulations, in driving non-building performance values across a wide range of green buildings.

Clinical results of endovenous LASER ablation (EVLA) using low linear endovenous energy density (LEED) combined with high ligation for great saphenous varicose veins.

PURPOSE: This study was designed to analyze the efficacy and complications in endovenous LASER ablation (EVLA) with 1470 nm diode lasers using low linear endovenous energy density (LEED) combined with high ligation for varicose veins of the great saphenous vein (GSV). METHODS: One hundred and sixteen limbs of 102 patients were analyzed using 6 W with 2 mm/s constant pullback speed delivered by 30 J/cm LEED. The SFJ was ligated with a small inguinal incision. The complications and status of the GSV were checked at 1 and 6 months postoperatively. RESULTS: The occlusion rates for the GSV were 98 (84.5 %) at 1 month and 116 (100 %) at 6 months, postoperatively. The rate of partial occlusion was higher in males than in females (p = 0.004). There were 2 DVT, 27 feelings of the cord (23.3 %), and 36 numbness at the knee area (31.0 %) at 1 month, and 3 feelings of the cord (3.4 %) and 6 numbness of the knee (8.6 %) at 6 months postoperatively. The diameter and depth of the GSV did not affect the rates of feeling of the cord or numbness (p = 0.728, 0.208, 0.247, 0.884, respectively). CONCLUSION: EVLA with a 1470-nm diode laser using low LEED combined with high ligation for the GSV has lower complication rates and higher occlusion rates of GSV.

Formaldehyde and acetaldehyde exposure mitigation in US residences: in-home measurements of ventilation control and source control.

Measurements were taken in new US residences to assess the extent to which ventilation and source control can mitigate formaldehyde exposure. Increasing ventilation consistently lowered indoor formaldehyde concentrations. However, at a reference air exchange rate of 0.35 h(-1), increasing ventilation was up to 60% less effective than would be predicted if the emission rate were constant. This is consistent with formaldehyde emission rates decreasing as air concentrations increase, as observed in chamber studies. In contrast, measurements suggest acetaldehyde emission was independent of ventilation rate. To evaluate the effectiveness of source control, formaldehyde concentrations were measured in Leadership in Energy and Environmental Design (LEED)-certified/Indoor airPLUS homes constructed with materials certified to have low emission rates of volatile organic compounds (VOC). At a reference air exchange rate of 0.35 h(-1), and adjusting for home age, temperature and relative humidity, formaldehyde concentrations in homes built with low-VOC materials were 42% lower on average than in reference new homes with conventional building materials. Without adjustment, concentrations were 27% lower in the low-VOC homes. The mean and standard deviation of formaldehyde concentration was 33 µg/m(3) and 22 µg/m(3) for low-VOC homes and 45 µg/m(3) and 30 µg/m(3) for conventional.

Atomically thin heterostructures based on single-layer tungsten diselenide and graphene.

Heterogeneous engineering of two-dimensional layered materials, including metallic graphene and semiconducting transition metal dichalcogenides, presents an exciting opportunity to produce highly tunable electronic and optoelectronic systems. In order to engineer pristine layers and their interfaces, epitaxial growth of such heterostructures is required. We report the direct growth of crystalline, monolayer tungsten diselenide (WSe2) on epitaxial graphene (EG) grown from silicon carbide. Raman spectroscopy, photoluminescence, and scanning tunneling microscopy confirm high-quality WSe2 monolayers, whereas transmission electron microscopy shows an atomically sharp interface, and low energy electron diffraction confirms near perfect orientation between WSe2 and EG. Vertical transport measurements across the WSe2/EG heterostructure provides evidence that an additional barrier to carrier transport beyond the expected WSe2/EG band offset exists due to the interlayer gap, which is supported by theoretical local density of states (LDOS) calculations using self-consistent density functional theory (DFT) and nonequilibrium Green's function (NEGF).

A comparative review of environmental concern prioritization: LEED vs other major certification systems.

The matter of environmental concern prioritization integrated into globally used green building rating systems is a fundamental issue since it determines how the performance of a structure or development is reflected. Certain nationally-developed certification systems are used globally without being subjected to adjustments with respect to local geographical, cultural, economic and social parameters. This may lead to a situation where the results of an evaluation may not reflect the reality of the region and/or the site of construction. The main objective of this paper is to examine and underline the problems regarding the issue of weighting environmental concerns in the Leadership in Energy and Environmental Design (LEED) certification system, which is a US-originated but globally used assessment tool. The methodology of this study consists of; (i) an analysis of the approach of LEED in the New Construction and Major Renovations scheme in version 3 (LEED NC, v.3) and the Building Design and Construction scheme in version 4 (LEED BD + C, v.4), (ii) case studies in which regional priority credits (RPCs) set by LEED for four countries (Canada, Turkey, China and Egypt) are criticized with respect to countries' own local conditions, and, (iii) an analysis of the approaches of major environmental assessment tools, namely; BREEAM, SBTool, CASBEE and Green Star, in comparison to the approach in LEED, regarding the main issue of this paper. This work shows that, even in its latest version (v.4) LEED still displays some inadequacies and inconsistencies from the aspect of environmental concern prioritization and has not yet managed to incorporate a system which is more sensitive to this issue. This paper further outlines the differences and similarities between the approaches of the aforementioned major environmental assessment tools with respect to the issue of concern and the factors that should be integrated into future versions of LEED.

Indoor air quality in green buildings: A case-study in a residential high-rise building in the northeastern United States.

Improved indoor air quality (IAQ) is one of the critical components of green building design. Green building tax credit (e.g., New York State Green Building Tax Credit (GBTC)) and certification programs (e.g., Leadership in Energy & Environmental Design (LEED)) require indoor air quality measures and compliance with allowable maximum concentrations of common indoor air pollutants. It is not yet entirely clear whether compliance with these programs results in improved IAQ and ultimately human health. As a case in point, annual indoor air quality measurements were conducted in a residential green high-rise building for five consecutive years by an industrial hygiene contractor to comply with the building's GBTC requirements. The implementation of green design measures resulted in better IAQ compared to data in references of conventional homes for some parameters, but could not be confirmed for others. Relative humidity and carbon dioxide were satisfactory according to existing standards. Formaldehyde levels during four out of five years were below the most recent proposed exposure limits found in the literature. To some degree, particulate matter (PM) levels were lower than that in studies from conventional residential buildings. Concentrations of Volatile Organic Compounds (VOCs) with known permissible exposure limits were below levels known to cause chronic health effects, but their concentrations were inconclusive regarding cancer health effects due to relatively high detection limits. Although measured indoor air parameters met all IAQ maximum allowable concentrations in GBTC and applicable LEED requirements at the time of sampling, we argue that these measurements were not sufficient to assess IAQ comprehensively because more sensitive sampling/analytical methods for PM and VOCs are needed; in addition, there is a need for a formal process to ensure rigor and adequacy of sampling and analysis methods. Also, we suggest that a comprehensive IAQ assessment should include mixed mode thermal comfort models, semi-volatile organic compounds, assessment of new chemicals, and permissible exposure levels of many known indoor VOCs and bioaerosols. Plus, the relationship between energy consumption and IAQ, and tenant education on health effects of indoor pollutants and their sources may need more attention in IAQ investigations in green buildings.

Contextualizing green building rating systems: Case study of Hong Kong.

The paper reports on a research study undertaken on the differentiation of green building certification systems at an international, national and local level. Through a cross comparison, authors are able to explain the differences by the contextualism theory which could be traced back to the fundamental divergence on lifestyles, preferences, urban morphology besides climatic variations. The discussion is derived from a study of three green rating systems representing international, national and local systems with reference to intentions, mechanisms and benchmarks to facilitate objective assessments. For the case of Hong Kong, local challenges are identified and compared with counterparts at a national level. Two residential projects having certified by the 'modified, localized' national system is selected for a case study for synopsis with a view to explain the cause and effect of transferability versus non-transferability of assessment credits and protocols. Introducing and applying national and international systems to a local context can detect flaws in local design practices that may be ignored in the local rating system.

Lateral ordering of PTCDA on the clean and the oxygen pre-covered Cu(100) surface investigated by scanning tunneling microscopy and low energy electron diffraction.

We have investigated the adsorption of perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA) on the clean and on the oxygen pre-covered Cu(100) surface [referred to as (√2 × 2√2)R45° - 2O/Cu(100)] by scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). Our results confirm the (4√2 × 5√2)R45° superstructure of PTCDA/Cu(100) reported by A. Schmidt et al. [J. Phys. Chem. 1995, 99,11770-11779]. However, contrary to Schmidt et al., we have no indication for a dissociation of the PTCDA upon adsorption, and we propose a detailed structure model with two intact PTCDA molecules within the unit cell. Domains of high lateral order are obtained, if the deposition is performed at 400 K. For deposition at room temperature, a significant density of nucleation defects is found pointing to a strong interaction of PTCDA with Cu(100). Quite differently, after preadsorption of oxygen and formation of the (√2 × 2√2)R45° - 2O/Cu(100) superstructure on Cu(100), PTCDA forms an incommensurate monolayer with a structure that corresponds well to that of PTCDA bulk lattice planes.

Impact of Green Hospital Design on Patients' Well-Being and Operating Cost of the Hospital: A Systematic Review.

Hospitals play a crucial role in providing medical care to patients, but they also have a significant environmental impact due to their high energy consumption and resource use. In recent years, there has been growing interest in the concept of green hospital design, which aims to reduce the environmental footprint of hospitals while simultaneously improving patient outcomes.10 articles were finalized for review and were coded in QDA Miner qualitative analysis software for descriptive and link analysis. Results indicated a strong correlation between green design aspects of hospital and patient well-being, it failed to provide any evidence of concrete relation between relation between green hospital design and lower operation cost."

ProLEED Studio: software for modeling low-energy electron diffraction patterns.

Low-energy electron diffraction patterns contain precise information about the structure of the surface studied. However, retrieving the real space lattice periodicity from complex diffraction patterns is challenging, especially when the modeled patterns originate from superlattices with large unit cells composed of several symmetry-equivalent domains without a simple relation to the substrate. This work presents ProLEED Studio software, built to provide simple, intuitive and precise modeling of low-energy electron diffraction patterns. The interactive graphical user interface allows real-time modeling of experimental diffraction patterns, change of depicted diffraction spot intensities, visualization of different diffraction domains, and manipulation of any lattice points or diffraction spots. The visualization of unit cells, lattice vectors, grids and scale bars as well as the possibility of exporting ready-to-publish models in bitmap and vector formats significantly simplifies the modeling process and publishing of results.

Unraveling van der Waals epitaxy: A real-time in-situ study of MoSe2 growth on graphene/Ru(0001).

In the present work we investigate the growth of monolayer MoSe2 on selenium-intercalated graphene on Ru(0001), a model layered heterostructure combining a transition metal dichalcogenide with graphene, using low energy electron microscopy and micro-diffraction. Real-time observation of MoSe2 on graphene growth reveals the island nucleation dynamics at the nanoscale. Upon annealing, larger islands are formed by sliding and attachment of multiple nanometer-sized MoSe2 flakes. Local micro-spot angle-resolved photoemission spectroscopy reveals the electronic structure of the heterostructure, indicating that no charge transfer occurs within adjacent layers. The observed behavior is attributed to intercalation of Se at the graphene/Ru(0001) interface. The unperturbed nature of the proposed heterostructure therefore renders it as a model system for investigations of graphene supported TMD nanostructures.