Search

Silicon inverted pyramid (IP) structures, with lower reflectance and increased surface recombination, are one of the best choices for light-trapping structures of high-efficiency silicon solar cells. The solution process of IP generally goes through three main steps: porous silicon etched by metal-assisted chemical etching, acid etching, and alkali anisotropic etching. In this paper, the role that acid modification plays in IP preparation and the application of our optimized texture for passivated emitter and rear solar cells (PERC) were investigated. Experimental results show that acid plays a decisive role in optimizing and modifying the morphology of porous silicon; thus, the morphology of porous silicon has no direct influence on the morphology of IP. In addition, the opening size of IP is mainly determined by the size of silicon micron holes modified by the acid process. PC1D simulation results manifest that IPs can increase the short-circuit current density (Jsc) of devices by 1.04 mA/cm2 and power conversion efficiency by 0.55%; hence, our optimized IP-based PERC achieve the highest simulative conversion efficiency of 23.21%. This is an effective and important way to manipulate the structure of IP, which points out the direction of fabrication and application of high-efficiency IP textures.

A core issue of the rapid developing online lending is to establish a sound credit rating method for borrowers. When examining 14,558 recovery rates of defaulted assets corresponding to each borrower of Renrendai platform from 2011 to 2016, we find that the current credit rating system (seven levels from AA, A, B, C, D, E and HR) cannot distinguish the distribution of recovery rates. Accordingly, this study proposes a credit rating approach for online lending platform using a Chinese sample, given that online lending has developed far more in China than in other countries and regions. Firstly, by referencing to the Sesame Credit and US FICO Credit systems, 15 indices are selected. Secondly, the K-Means clustering credit rating method using recovery rate is used to reclassify borrowers, solving the problem that Renrendai’s credit rating system cannot distinguish borrowers with assets of different recovery rates. However, this simple reclassification lead to another issue that borrowers with high credit rating are more than borrowers with low credit rating (the so-called "inverted pyramid" problem). Therefore, finally, an augmented credit rating method is developed to reclassify borrowers, which integrates factor analysis and K-Means clustering using recovery rate. By using this finalized method, borrowers with different recovery rates are distinguished clearly to different credit levels.

Single side optical design of solar cells has limitations. In this paper, we studied the optical properties of inverted pyramid textured passivated emitter and rear cell (PERC) solar cells, conside...

The random inverted pyramid texture has been extensively studied experimentally in high-efficiency monocrystalline silicon solar cells due to its superior optical properties. In this paper, a random inverted pyramid structure model was established, and the optical performance was studied by the ray tracing method. It has five common light paths and can achieve lower reflectance than random upright pyramids. To further analyze the optical properties of random inverted pyramids, a simplified random inverted pyramid model, which consists of two overlapping inverted pyramids, was studied and analyzed in detail. The proportions of the light path related to different overlapping regions, and the reflectance ranging from 10.11% to 10.64%, can be obtained, which is lower than the reflectivity of random upright pyramids. We believe that the random inverted pyramid texture can have a wide range of applications in high-efficiency monocrystalline silicon solar cells.

Silicon (Si) has been investigated as a promising photoelectrode material for use in photoelectrochemical water splitting. However, development of Si photocathodes that can operate at a high photoc...

Inverted pyramid-texturing of silicon surface has been proven to have great application potential in silicon solar cells. In this paper, we utilized Ag-assisted chemical etching (Ag–ACE) technology combing with polyvinylpyrrolidone (PVP) to fabricate an inverted pyramid textured Si surface. We call it Ag@PVP–ACE. The effect of different experimental parameters on etching results was observed. We show that the microstructure of the Si surface exhibited two states as the concentration of NH4HF2 and PVP concentration changed: polishing and inverted pyramid texturing. Meanwhile, we found inverted pyramids easier to form at the high temperature and low H2O2 concentration of the etching system. Consequently, compared to inverted pyramid structures fabricated by nanostructure rebuilding (NSR) technology and Ag@PVP–ACE, we consider that Ag@PVP–ACE technology could become a viable strategy for fabricating inverted pyramid textured Si wafers in Si solar cells production.

On first glance, distribution strategy seems to be the staidest of all the marketing functions, yet it is fundamental to business success. This chapter shows how consumers have created new strategies for dealing with those goods and services that they no longer need or for reclaiming those goods that may to the untrained eye appear to be worthless (broken, disfigured, out of style, for example). It presents The Inverted Pyramid of Sustainability and discusses specific marketing strategies that relate to each section. The chapter looks at examples of these redistribution channels to see how consumers in these markets are using these channels to enact values of sustainability. It considers how corporations have been tackling these issues, oftentimes in response to grassroots consumer actions. The chapter presents exercises designed to open up student debate around sustainable distribution and the role consumers play therein.

This paper reports inverted pyramid microstructure-based single-crystalline silicon (sc-Si) solar cell with a conversion efficiency up to 20.19% in standard size of 156.75 × 156.75 mm2. The inverted pyramid microstructures were fabricated jointly by metal-assisted chemical etching process (MACE) with ultra-low concentration of silver ions and optimized alkaline anisotropic texturing process. And the inverted pyramid sizes were controlled by changing the parameters in both MACE and alkaline anisotropic texturing. Regarding passivation efficiency, the textured sc-Si with normal reflectivity of 9.2% and inverted pyramid size of 1 μm was used to fabricate solar cells. The best batch of solar cells showed a 0.19% higher of conversion efficiency and a 0.22 mA cm−2 improvement in short-circuit current density, and the excellent photoelectric property surpasses that of the same structure solar cell reported before. This technology shows great potential to be an alternative for large-scale production of high efficient sc-Si solar cells in the future. Electronic supplementary material The online version of this article (10.1186/s11671-018-2502-9) contains supplementary material, which is available to authorized users.

The recent demonstration of the effectiveness of low-dose aspirin administered from the first trimester in the prevention of preeclampsia will probably lead to establishing and radicating the “inverted pyramid” screening model for preeclampsia. Such a multiparametric approach for the screening of preeclampsia in the first trimester, albeit highly sensitive in identifying early-onset disease, is poor at screening the forms of preeclampsia occurring close to term. Late-onset preeclampsia is 3 to 6 times more common than early-onset preeclampsia and currently represents the major determinant of maternal morbidity related to hypertensive disorders of the pregnancy. On this ground, we discuss our idea to construct a second “screening checkpoint” in the third trimester with the aim of reassessing the risk of preeclampsia of those women who screened negative in the first trimester. If implemented, the sequential screening model we propose would convert the “inverted pyramid model” into an “arrow model” for the antenatal care of preeclampsia.

Information retrieval systems embed temporal information for retrieving the news documents related to temporal queries. One of the important aspects of a news document is the focus time , a time to which the content of document refers. The contemporary state-of-the-art does not exploit focus time to retrieve relevant news document. This paper investigates the inverted pyramid news paradigm to determine the focus time of news documents by extracting temporal expressions, normalizing their value and assigning them a score on the basis of their position in the text. In this method, the news documents are first divided into three sections following the inverted pyramid news paradigm. This paper presents a comprehensive analysis of four methods for splitting news document into sections: the paragraph-based method, the words-based method, the sentence-based method, and the semantic-based method (SeBM). Temporal expressions in each section are assigned weights using a linear regression model. Finally, a scoring function is used to calculate a temporal score for each time expression appearing in the document. These temporal expressions are then ranked on the basis of their temporal score, where the most suitable expression appears on top. The effectiveness of the proposed method is evaluated on a diverse dataset of news related to popular events; the results revealed that the proposed splitting methods achieved an average error of less than 5.6 years, whereas the SeBM achieved a high precision score of 0.35 and 0.77 at positions 1 and 2, respectively.

Transparent substrates with antifogging and antireflection ability are of extreme significance for optical devices, because they alleviate performance loss and maintenance costs. Here, we reported that a multifunctional film, with excellent mechanical properties, can be fabricated on the PMMA surface via the micro-transfer printing method. In particular, the synergistic effect of the inverted pyramid microstructure and SiO2 nanoparticles gives the film excellent antireflective, superhydrophilic and antifogging properties, and the silica sol firmly adheres to the PMMA substrate via the silane coupling agent, which exhibits an encouraging prospect of practical applications from lenses for personal and sports eyewear to transparent displays and sensors, etc.

In recent years, the idea of the inverted pyramid of prenatal care and monitoring has emerged, for the purpose of prediction and prevention, early detection and treatment of health disorders of the fetus. Is this enough? If we analyze the period behind us, progress has been made in the field of detection of multiple pregnancies, dating of pregnancy and prenatal detection of chromosomal and structural fetal disorders, as well as a small amount of progress in terms of prediction and prevention of preeclampsia. If these disorders are the consequence of the disturbed or dysfunctional placentation, they are rooted at the time of implantation. This means that the changes that lead to the dysfunctional implantation should be sought in the pre-implantation period, in relation between the embryo and the endometrium. An extended inverted pyramid is necessary to find better results in perinatal medicine. This means that the interventions should be focused on the preconception and peri-implantation periods. The therapy should be on the subcellular and genetic level by applying the latest biotechnological procedures. It is possible that the time is approaching when the listed disorders of a pregnancy will be the indications for the application of a non stimulated in-vitro fertilization (IVF) (without ovary stimulating medication) with the use of new biotechnological achievements.

Herman Daly's view of the economy as an “inverted pyramid” sitting on top of essential raw material inputs is compelling, but not readily visible in monetary data, as the contribution of primary sectors to value added is typically low. This article argues that “forward linkages”, a classical development theory concept capturing the relevance of a sector for downstream activities, is an informative and complementary measure to identify key sectors. Using Input-Output (IO) data from eighteen European countries, we identify mining as the sector with the highest average forward linkages, and confirm the consistency of this result across countries via cluster analysis. By treating IO tables as the adjacency matrix of a directed network, we then build and visualise national inverted pyramid networks, and analyse their structure. Our approach highlights the role of natural resources in providing the necessary inputs to modern European economies.

Many studies of structure in present-day Western news texts have shown that the dominant structure is the inverted pyramid, even if the use of a chronological narrative structure is acknowledged. However, the relevant literature has exclusively investigated Western news texts. In this study, we challenge the dominance of the inverted news structure by including a non-Western and less-investigated culture and ask whether textual structure of news texts can differ between cultural contexts. In total, 100 crime news texts from national Iranian and Dutch newspapers were analyzed for both the overall text and the journalists’ statements. Those texts that showed a hybrid structure (combining inverted pyramid and chronology) were subsequently studied qualitatively to understand how chronology is applied in them. News texts from the two cultures were significantly different in their structure. Qualitative analysis of the journalistic statements uncovered a quotation-based structure, a way of news writing in Iranian journalistic statements in which the journalist mainly narrates reporting eventualities that are new to Western eyes. The study offers implications for further ethnography of news and communication, suggesting that the role, pattern and effects of (journalistic) communication can be culture-specific.

The objective of this study is to identify various characteristics of accidents in Japan’s five major ports and to correlate the design and construction factors of these ports with accidents to better predict the occurrence of accidents based on port design and construction. The five major ports in Japan include the ports of Tokyo, Yokohama, Nagoya, Kobe, and Osaka as determined by their foreign container volumes. Data from the Japan-Marine Accident Risk and Safety Information System (J-MARISIS) is analyzed using the 4M Overturned Pyramid (MOP) model. The MOP model is a 3-dimensional model appearing as a three-sided inverted pyramid, consisting of 4 corners that represent the 4M factors (man, machine, media, and management) with the man factor always located at the bottom. The data analysis revealed that each port has its highest causative factor, but the highest causative factor for accidents in Japan’s five big ports is the man factor, followed by the management factor, media factor, and machine factor, in that order. The highest causative factor is also affected by the man-machine relationship. A correlation between port design or construction and marine accidents is not identified using the current MOP Model method, although design is accounted for in the machine factor.

The inverted pyramid microstructures (IPMS) were fabricated jointly by metal-assisted chemical etching (MACE) technology with extremely low concentration of silver ions to formed nanopores and nanostructure rebuilding (NSR) treatment of NH4HF2 solution. The results show nanopores were achieved with the aid of Ag-MACE technology, which diameter was mainly affected by the action of Ag ions, and depth was yet mainly influenced by HF concentration. Textured IPMS single-crystalline silicon (sc-Si) solar cells with the diameter of 1 μm and reflectivity of 8.62% were large-scale prepared. Benefiting from better light-trapping ability, the photoelectric conversion efficiency of IPMS sc-Si solar cells in standard size of 156.75 × 156.75 mm2 achieved 22.06%. Simultaneously, the short-circuit current was increased by 71 mA. This promising technology could become a viable solution for industrial production of highly efficient sc-Si solar cells in the foreseeable future.

As the development of PV industry, inverted pyramid has become an ideal structure to replace the upright pyramid to boost the cell efficiency. However, there is a serious gap in how surface structures with different-sized inverted pyramids influence the cell performance. In this paper, detailed comparison of optical properties and cell performances among different-sized inverted pyramids and upright pyramid are carried out to give a clear evaluation of how structure influences cell performance. The different-sized inverted pyramids were fabricated with the help of Ag manipulation, which can be attributed to the dramatic increase in the nucleation points prior to Cu deposition due to the existence of Ag during the etching process. Finally, the results indicate a strong connection with the structure size, where the largest size produces the best cell performance. The average cell efficiency of the inverted pyramids with the largest structure size is 19.955%, which is 0.15% higher than that of the upright pyramids, and the best cell efficiency obtained on the largest inverted pyramids can be as high as 20.094%, indicating that the large inverted pyramids have a great advantage in increasing the cell efficiency.

The imperative on speed in the news media, combined with the inverted pyramid form of news writing, have well-documented strengths, enabling important information to be communicated quickly and clearly. A preoccupation with this part of journalism practice, however, within the news media industry and among scholars, obscures what James Carey has called the “curriculum of journalism.” To be properly understood, Carey argued journalism needs to be examined as a corpus that includes a wide range of materials extending to book-length journalism. Longer articles and book-length works add substantially to the store of relevant and newsworthy information. They also significantly enlarge public understanding of people, events and issues of the day by exploring them in depth, usually by taking a narrative approach in the writing. This article brings to the fore the contribution of these slower forms of journalism by examining immediate and longer-term coverage of two historic news events: the dropping of the first...

With the increasing amount of data available in digital media, new professional practices emerged in journalism to gather, analyze and compute quantitative data that aims to yield potential pieces of information relevant to news reporting. The constant evolution of the field motivated us to perform a systematic review of the literature on data-driven journalism to investigate the state-of-art of the field, concerning the process, expressed by the “inverted pyramid of data journalism”. We aim to understand what are the techniques and tools that are currently being used to collect, clean, analyze, and visualize data. Also, we want to know what are the data sources that are presently being used in data journalism projects. We searched databases that include publications from both fields of computing and communication, and the results are presented and discussed through data visualizations. We identified the years with the highest number of publications, the publications’ authors and the fields of study. Then, we classified these works according to the changes in quantitative practices in journalism, and to the contributions in different categories. Finally, we address the challenges and potential research topics in the data journalism field. We believe the information gathered can be helpful to researchers, developers, and designers that are interested in data journalism.

The objective of the research reported in this article was to analyse and quantify the narrative techniques employed in videos embedded in the home pages of five Spanish online newspapers. For the purpose of tracing the evolution of the approaches taken by these digital dailies away from the traditional narrative models used in television production, two separate study samples representing video reporting published online in 2011 and 2014 were examined. Findings show that material outsourced from agencies largely comprised short videos with voiceovers that conformed to the narrative structures of traditional journalism whereas those produced in-house by the five online dailies studied offered an innovative model that borrowed freely from other genres, involved longer stories supported by sound bites rather than voiceovers and were structured along lines other than those of the classic inverted pyramid.

Flexible ultrathin c-Si (U-Si) solar cell is widely researched for its potential usage in places with various shapes and sizes. However, light incident angle (θ) varies with positions on the same cell accompanied with the easy crack of cell due to surface textures when the U-Si cell is under bending. Therefore, the fabrication of efficient antireflectance structures with both quasi-omnidirectional performance and superior mechanical performance is greatly required. Here, size control of inverted pyramid (IP) from nano to micro scale as antireflectance structures is realized by altering ρ ([HF]/[HF] + [H2O2]) values at room temperature. The IP is obtained through the nanostructure rebuilding (NSR) treatment of Ag assisted chemical etched nanostructures. In comprehensive consideration of optical and mechanical performances, IP-60 (ρ = 60%) textured 40 µm U-Si cell is successfully fabricated with a short-current density of 34.8 mA/cm2 and energy-conversion efficiency of 17.44%, showing an 0.2 mA/cm2 and 0.13% improvement respectively compared with that of the micro pyramids (MP) based one. Moreover, the quasi-omnidirectional characteristics of IP-60 based 40 μm cell over 0–60° is demonstrated by experiment and simulation. The above finding makes it possible to broaden the application scope of U-Si cells into some new areas like stratospheric airships and wearable electronics.

Display Omitted Inverted nanopyramids were fabricated by interference lithography and KOH etching.The reflectivity of inverted nanopyramids below 10% over visible region.A 67% increase in efficiency was achieved by nanopyramid texturing. We report on a maskless and scalable technique for fabricating nano-scale inverted pyramid structures suitable for light management in crystalline silicon solar cells. This technique utilizes interference lithography and subsequent combined dry and KOH wet pattern transfer etching techniques. The inverted nanopyramid structures suppress the total reflection at normal incidence to below 10% over the entire visible range. The overall efficiency of the solar cell has been increased by 67% with the inverted nanopyramid texturing. The standard dual MgF2/ZnS anti-reflection coating further enhanced the overall efficiency by 5.79%.

This work reports on the properties of cubic silicon carbide (3C-SiC) grown epitaxially on a patterned silicon substrate composed of squared inverted silicon pyramids (ISP). This compliant substrate prevents stacking faults, usually found at the SiC/Si interface, from reaching the surface. We investigated the effect of the size of the inverted pyramid on the epilayer quality. We noted that anti-phase boundaries (APBs) develop between adjacent faces of the pyramid and that the SiC/Si interfaces have the same polarity on both pyramid faces. The structure of the heterointerface was investigated. Moreover, due to the emergence of APB at the vertex of the pyramid, voids buried on the epilayer form. We demonstrated that careful control of the growth parameters allows modification of the height of the void and the density of APBs, improving SiC epitaxy quality.

The external quantum efficiency of organic light-emitting diodes (OLEDs) was suppressed by the wave guide mode in the glass substrate and organic layers. In this paper, a mechanism is developed to simulate the optical luminous field for OLEDs based on inverted pyramid substrate structure. Monte Carlo method was used to optimize the structural parameters to enhance the external quantum efficiency of device by changing the substrate structure. A considerable enhancement in the extraction efficiency of the OLED is expected theoretically, and near 42% out-coupling efficiency was achieved in experiment without affecting the electroluminescent spectrum.

18th International Conference on Metal Organic Vapor Phase Epitaxy (ICMOVPE)JUL 10-15, 2016San Diego, CA; International audience; We have examined 200 mm GaN on silicon wafers, while varying the AlN nucleation temperature, and have found that higher temperatures result in a more convex bow on the wafers. In addition, by performing full wafer defect mapping, we have found that a higher nucleation temperature results in a higher density of inverted pyramid defects, which have previously been found to reduce the breakdown voltage of GaN on silicon layers. We have performed electrical measurements on a wafer with the lowest temperature AlN layer, which is still within our bow specification, and which therefore has the lowest density of inverted pyramid defects. This wafer showed the same leakage current density for both very small and very large test structures (2x10(-3) and 18.7 mm(2) respectively), with all but one of our large structures mAlNtAlNing a breakdown voltage greater than 700 V. This is a very promising result for high yield of devices on 200 mm GaN on silicon wafers.

Inverted-pyramid silicon nanopore arrays are realized with a well-controlled, three-step, anisotropic wet etching process with different KOH bath temperatures. The influence of etchant concentration and temperature on the etching rate is investigated. Nanopore arrays with an average size of 100 nm and individual nanopores with feature sizes as small as 30 nm were successfully fabricated at low cost using this method. This study paves the way toward the controllable, large-scale production of arrays of inverted-pyramid nanopores with desired size.

This article aims to discuss the impact of the characteristics of the Twitter platform on the application of standard journalistic technique (TRAQUINA, 2008) during the creation and production of news releases as tweets and, at the same time, it seeks to identify their specifications regarding traditional journalistic utterances. Through the analysis of 134 tweets collected from newspaper profiles of Folha de S. Paulo, Zero Hora and Diário Popular, we have obtained indications that led us to confirm our central assumption. In other words, the hierarchical pattern and purpose that guide the creation of standard news, and therefore, the special language that characterizes traditional journalism, begin to give way to models that are more horizontal and interactive, that redesign the standard technique (based on the model of the Inverted Pyramid) and thus, modify journalistic writing - interfering in its discursive effects (GOMES, 2000).

This paper is to investigate the possibility to fabricate the inverted-pyramid structure on silicon wafer base solar cell by using laser scribing technology. The UV spectrometer and SEM had also been used to observe the reflectance and microstructure of the wafer surface. In this experiment, a Q-switched Nd:YAG laser operating at wavelength of 1064nm is used to scribe on the p-type wafer surface to produce inverted-pyramid structure. In order to remove the laser damage, we used acid etching and Alkaline etching solutions to smooth the damage region and inverted pyramid structure formed, simultaneously.

In the past, clinical phase I trials often suffered from low response rates and inadequate experimental drug doses. Over the past decade, however, phase I trials have evolved from simple dose-finding studies to trials that might provide clinically relevant therapeutic opportunities for patients with advanced-stage cancer for which no standard therapies are available. In the future, the routine use of modern technologies such as large-scale genome sequencing will help to unravel the specific biology of a patient's cancer. Such tools will expand our knowledge about genetic aberrations and might provide opportunities for the development of novel, molecular targeted therapies for patients with refractory cancer. Increasingly, the focus will likely turn from carrying out large randomized trials in unselected patients to conducting smaller biomarker-driven trials in selected patients with known molecular aberrations. We expect that these new strategies will enhance response rates as appropriate patients are targeted, therefore sparing those patients who are unlikely to benefit.

This article discusses the correlation between market structure and value GetCapabilities of major procedures of the PV industry, from the results we can find: As the number of enterprises involved in four procedures of the industrial chain increases, the degree of monopoly of market structure in all procedures are becoming more and more weaker, increasing the level of competition, which resulting in decreasing order of the corresponding distribution of profits, demonstrated as a "inverted pyramid" structure. Market structure of value chain in every procedure determines its ability to obtain the profits. That the industrial organization of PV industry can be explained by the SCP paradigm of Harvard School.

In this paper, we present a novel silicon (Si) subwavelength-scale surface structure (SWSS) fabrication process using the silica sphere (SS) lithography technique, which allows controllable geometries. The process involves a new cost-effective solvent-controlled spin-coating method that deposits SS on large Si surface areas with enhanced SS monolayer coverage and uniformity compared to conventional methods. The larger areas and rapid, low cost processing allow colloidal sphere lithography to be realistically used for solar cells. We successfully demonstrate 1.57 &mu, m diameter SS on a 2-inch round Si wafer with more than 95% SS monolayer coverage and great uniformity. Using these deposited SS, a SWSS fabrication process was designed and successfully demonstrated Si inverted pyramid structures with dimension on the order of 1.1 &mu, m, thus potentially providing a new technique for effective light-management of thin crystalline Si solar cells.

In this work we identified the nucleation sites of inverted pyramid defects in 4H-SiC epilayers using AFM and KOH etching and proposed a mechanism for its formation. Partial dislocations, bounding the stacking faults, mostly aligned along the directions, were found at the base of the inverted pyramid defects. It is shown that the basal plane dislocations, serve as nucleation centers for stacking faults, and eventually the formation of inverted pyramid defects. A geometrical model is formulated to explain the formation mechanism of inverted pyramid defects.

Lens-based optical concentrators are currently the most common in concentrator photovoltaic systems. This paper discusses experimental results to quantify the effects of temperature on the primary optical elements of three commercial Fresnel-based designs. The designs are: Silicon on Glass Primary with no secondary, PMMA Primary with a Truncated Inverted Pyramid secondary, and a PMMA 4 quadrant Fresnel – Kohler system. We quantify the effects of temperature on the irradiance profile with the variation in peak to average ratio of from 25 – 50 ° C. Furthermore, the effect of temperature on chromatic aberration is represented with the ratio of the top subcell current to middle subcell for a standard triple junction germanium-based cell. For the system with the lowest peak-to-average ratio, PMMA-based 4 Fresnel-Kohler design, we observed a change of 2% in the subcell ratio when the lens was heated to 50 °C.

Drawing on an analogy between discourse and syntactic trees, this paper chooses 359

Thick GaN films with high quality have been grown on (0001) sapphire substrate in a home-made vertical HVPE reactor. Micron-size hexagonal pits with inverted pyramid shape appear on the film surface, which have six triangular {10-11} facets. These I {10-11} facets show strong luminescence emission and are characteristic of doped n-type materials. Broad red emission is suppressed in {10-11} facets and is only found at the flat region out of the pit, which is related with the decreasing defects on {10-11} facets. Low CL emission intensity is observed at the apex of V-shape pits due to the enhanced nonradiative recombination. Raman spectra show that there are higher carrier concentration and low strain in the pit in comparison to the flat region out of the pit. The strain relaxation may be the main mechanism of the V-shape pits formation on the GaN film surface. (c) 2006 Elsevier B.V. All rights reserved.

A weird effect of lattice polarity on the morphology of InN nanocolumns (NCs) via position- and lattice-polarity-controlled selective area growth (SAG) is demonstrated. In-polar and N-polar InN NCs grown on pillar-patterned GaN template were investigated experimentally and theoretically. Growth behaviors and morphology of InN NCs are analyzed, which exhibit different behaviors for opposite polarities, with pyramid growth front and inverted pyramid growth front for the In- and N-polarities, respectively. Theoretical calculation shows that the diffusion barriers of In and N adatoms on (0001) plane are 0.25 eV and 1.20 eV, respectively, which is about 2-fold larger than that of (0001) plane, resulting in opposite growth behaviors. The polarity inversion phenomenon in In-polar InN NCs provides another strong evidence for the polarity driven growth mechanism.

We discovered a technical solution of such outstanding importance that it can trigger new approaches in silicon wet etching processing and, in particular, photovoltaic cell manufacturing. The so called inverted pyramid arrays, outperforming conventional pyramid textures and black silicon because of their superior light-trapping and structure characteristics, can currently only be achieved using more complex techniques involving lithography, laser processing, etc. Importantly, our data demonstrate a feasibility of inverted pyramidal texturization of silicon by maskless Cu-nanoparticles assisted etching in Cu(NO3)2 / HF / H2O2 / H2O solutions and as such may have significant impacts on communities of fellow researchers and industrialists.

In this paper an easy, reproducible and inexpensive technique for the production of solid state nanopores, using silicon wafer substrate is proposed. The technique is based on control of pore formation, by neutralization etchant (KOH) with a strong acid. Thus, a local neutralization is produced around the nanopore, which stops the silicon etching. The etching process was performed with 7M KOH at 80°C, where 1.23 µm/min etchings speed was obtained, similar to those published in literature. The control of the pore formation with the braking acid method was done using 12M HCl and different extreme conditions: i) at 25ºC, ii) at 80°C and iii) at 80°C applying a potential. In these studies, it was found that nanopores can be obtained automatically, addressable and at a low cost. Additionally, a way to obtain the nanopores leaving the silicon wafer completely clean after the etching process was found. This method offers the possibility of an efficient scale-up from the laboratory to production scale. Fil: Vega Moreno, Milena Amparo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina. Universidad Tecnológica Nacional; Argentina Fil: Lerner, Betiana. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Lasorsa, Carlos Alberto. Universidad Tecnológica Nacional; Argentina Fil: Pierpauli, Karina Alejandra. Comisión Nacional de Energía Atómica; Argentina Fil: Perez, Maximiliano Sebastian. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina

Parapharyngeal space is a potential space in the neck in the form of an inverted pyramid and can be divided into pre- and post-styloid compartment. Salivary gland tumors commonly arise from the pre-styloid compartment and neurogenic tumors and paragangliomas from the post-styloid compartment. These tumors can have a highly variable presentation due to their location which often also makes it difficult to get a confirmed pre-operative diagnosis due to their inaccessibility. In such cases, diagnosis is often radiological. We present two cases of parapharyngeal space masses, where, in spite of thorough pre-operative workup, final diagnosis turned out to be a surprise.

Here we propose a texturing method for crystal Silicon solar cells, which enables a low reflecting surface of random double inverted pyramids easily. The surfaces of the reported crystal Silicon solar cells that have world-record efficiency were inverted pyramids, whereas the widely-used conventional texturing surface is a random pyramid surface by alkaline solution. Our method can realize a random double inverted pyramid surface of nanometer-sized inverted pyramids on micrometer-sized inverted pyramids without photo-lithography. This random double inverted pyramid surface is obtained by a kind of fluorinating agent of N-fluoropyridinium salt, under optical illuminating and heating condition. Using reflectance measurement with integrating sphere, we realized a black surface of 6.3% reflectance, whereas the as-slice surface is 23% and random pyramid surface is 11.9%

Two novel texture schemes for the front of a c-Si silicon wafer solar cell are presented. The “bipyramid” texture is of two inverted pyramids of similar sizes laid out in alternating order. The “patch” texture uses a checkerboard layout of blocks of parallel grooves, with the grooves of alternating blocks perpendicularly oriented to each other. We estimate that these textures, which almost fully trap light for the first six passes through the substrate, can deliver better optical performance than the standard inverted pyramid texture, especially in narrow-band applications.

Funnel charts are used to show the progressive reduction of data as they go down one level to the next. The chart consists of an inverted pyramid, or funnel, divided into different levels. Each level has its own area, which is proportional to a given percentage value. A funnel chart is similar to a pie chart in that both express a whole divided into its constituent parts. But, the funnel chart specifies levels, which succeed one another in a very precise sequence. This sequence may express a hierarchical order, the steps of a process, and so on. A pie chart cannot do this.

This article describes a method that was used as a supervision and teaching tool to assist student counselors in developing client conceptualization skills.

A novel electrodeless-dielectrophoresis (EDEP) device incorporating three-dimensional (3D) inverted-pyramid arrays is proposed for the trapping and separation of nanoparticles. The electrokinetic phenomena in the proposed device are investigated both numerically and experimentally. The results reveal that the pyramid structures induce a 3D squeezed electric field, which allows particle trapping with a lower driving voltage than that required in traditional two-dimensional (2D) EDEP devices. Overall, the proposed EDEP device provides a mass-producible solution for nanoparticle-trapping applications and overcomes the Poisson statistical limit inherent in 2D nanogap-based EDEP devices with smaller (pL) sample volumes.