Search

It is well known that cyan-emitting phosphors play a very important role in full-spectrum white LEDs. A large number of cyan-emitting phosphors have been reported in the past few years, however, most of them can only be effectively excited by near-ultraviolet light. There are very few cyan-emitting phosphors that can be intensively excited by blue light (440 and 470 nm). Here, a novel blue-light excitable cyan-emitting phosphor BaLu1.95Ce0.05Al2Ga2SiO12 with excellent performance is reported. The cyan phosphor has a cubic structure in space group I a 3 ¯ d with a = 1.205379(3) nm, which can be easily obtained through a solid-state reaction pathway. The emission peak of the cyan phosphor is located at 500 nm and its internal quantum efficiency is as high as 90.01% when excited at 455 nm at 25 °C. The cyan phosphor exhibits superior resistance against thermal quenching of luminescence, and its intensity at 125 °C is as strong as 92.14% of the intensity at room temperature. Meanwhile, it also shows an outstanding resistance against water, where its luminescence intensity is hardly changed after being immersed in pure water for 528 h. The white LED lamp prepared by employing the obtained BaLu1.95Ce0.05Al2Ga2SiO12 as cyan phosphor displays remarkable optical properties with CCT = 4441 K, Ra = 93.7, CRI = 90.4 and CIE 1931 (x, y) as (x = 0.3648, y = 0.3752). The experimental results demonstrate that BaLu1.95Ce0.05Al2Ga2SiO12 is a promising cyan-emitting phosphor with great application potential in full-spectrum white LEDs.

Fly ash cement is used to solidify marine clay to prepare marine-clay-based cemented paste backfill (MCCPB) to fill the underground goaf of mines, which not only utilizes solid waste such as fly ash and marine clay, but also controls surface subsidence and protects the environment. To simulate the complex underground mine water environment of the filling body, a dry-wet cycle aquatic environment test under different material ratios and curing ages was designed. The water absorption and unconfined compression strength (UCS) of MCCPB with curing ages of 7 and 28 days under the action of 0, 1, 3, and 7 dry-wet cycles were investigated. The results indicate as the number of dry-wet cycles increases, the surface of MCCPB becomes significantly rougher, and the water content and the solid mass decrease accordingly. Different ratios and curing ages of MCCPB in dry-wet cycles of the UCS tend first to increase, then decrease. Meanwhile, the stress-strain curve of the specimen shows that the trend in the elastic modulus is consistent with that of UCS (first increasing, then decreasing), and that, the minimum UCS value of the specimen still meets the early strength requirements of cemented paste backfill in coal mine geothermal utilization. On the one hand, it proves the feasibility of fly ash cement-solidified marine clay for use as cemented paste backfill in coal mines; on the other hand, it also expands the available range of cemented paste backfill materials in coal mines.

Background Proton pump inhibitors (PPI) and histamine 2 receptor antagonists (H2RA) have been widely used as stress ulcer prophylaxis (SUP) in critically ill patients, however, its efficacy and safety remain unclear. This study aimed to assess the effect of SUP on clinical outcomes in critically ill adults. Methods Literature search was conducted in PubMed, EMBASE, Web of Science, and the Cochrane database of clinical trials for randomized controlled trials (RCTs) that investigated SUP, with PPI or H2RA, versus placebo or no prophylaxis in critically ill patients from database inception through 1 June 2019. Study selection, data extraction and quality assessment were performed in duplicate. The primary outcomes were clinically important gastrointestinal (GI) bleeding and overt GI bleeding. Conventional meta-analysis with random-effects model and trial sequential analysis (TSA) were performed. Results Twenty-nine RCTs were identified, of which four RCTs were judged as low risk of bias. Overall, SUP could reduce the incident of clinically important GI bleeding [relative risk (RR) = 0.58; 95% confidence intervals (CI): 0.42–0.81] and overt GI bleeding (RR = 0.48; 95% CI: 0.36–0.63), these results were confirmed by the sub-analysis of trials with low risk of bias, TSA indicated a firm evidence on its beneficial effects on the overt GI bleeding (TSA-adjusted CI: 0.31–0.75), but lack of sufficient evidence on the clinically important GI bleeding (TSA-adjusted CI: 0.23–1.51). Among patients who received enteral nutrition (EN), SUP was associated with a decreased risk of clinically important GI bleeding (RR = 0.61; 95% CI: 0.44–0.85; TSA-adjusted CI: 0.16–2.38) and overt GI bleeding (RR = 0.64; 95% CI: 0.42–0.96; TSA-adjusted CI: 0.12–3.35), but these benefits disappeared after adjustment with TSA. Among patients who did not receive EN, SUP had only benefits in reducing the risk of overt GI bleeding (RR = 0.37; 95% CI: 0.25–0.55; TSA-adjusted CI: 0.22–0.63), but not the clinically important GI bleeding (RR = 0.27; 95% CI: 0.04–2.09). Conclusions SUP has benefits on the overt GI bleeding in critically ill patients who did not receive EN, however, its benefits on clinically important GI bleeding still needs more evidence to confirm.

Multilayered inorganic transparent materials have been widely used as laser materials, scintillators and phosphors due to their excellent combined properties or functions. However, owing to the limitation of the current preparation technology, only the ceramics with cubic crystal structure could be fabricated into multilayered transparent materials, which has greatly obstructed the diversity of multilayered transparent materials. Here we report a novel non-cubic multilayered transparent phosphor with a ceramic/glass/ceramic sandwich-like structure prepared by controlling crystallization from Eu2O3-SrO-Al2O3-SiO2 bulk glass. The ceramic thicknesses, total transmittances, emission colors and the fluorescence quantum yields of the samples can be adjusted continuously within a certain range. The multilayered transparent phosphor could be used as a potential candidate for the white LEDs with high color rendering index. It can be anticipated that the controlled crystallization from bulk glass method is a simple, fast, cost-effective and promising synthesis approach to prepare non-cubic transparent materials with ceramic/glass/ceramic structures.

China is a major coal producing country, and also one of the countries which has the most serious coal mine accidents around the world. As a result of geological conditions, underground mining is the main way that coal is exploited in China; serious underground disasters and the corresponding fatality rate are much higher than is the case for surface mining. Although safer modern underground mining methods have been introduced across China, accidents still lead to fatalities and the loss of revenue in some mines. It is important to establish a georeferenced coal mine disasters (CMD) database to aid researchers and decision makers in better understanding the spatio-temporal distribution of such accidents across in China. This study has proposed a method to develop a georeferenced spatio-temporal CMD database via a geographic information system (GIS) platform based on statistical data released by the State Administration of Coal Mine Safety (SACMS) for the period between 2000 and 2015. The different levels and spatio-temporal characteristics of coal mining accidents were analyzed, and the space-time scan statistic permutation (STSSP) model was carried out to detect the CMD clusters; and finally, a spatio-temporal cluster analysis of Chinese coal mining accidents in 2000 and 2015 was conducted.

BaLu1.94Al4SiO12:0.06Ce3+ (BLASO:0.06Ce3+) green-emitting phosphor could be easily obtained by a conventional solid-state reaction method at 1400 °C. BLASO:0.06Ce3+ possesses the garnet structure ( Ia 3 d space group) with the lattice parameter a = 11.9222(0) A. The emission peak of BLASO:0.06Ce3+ is located at 513 nm and its photoluminescent quantum yield is determined to be 92.4% at 25 °C when excited at 450 nm. BLASO:0.06Ce3+ presents excellent thermal properties, with the photoluminescence intensity at 200 °C only decreased to 91.5% of its room temperature value. A phosphor-converted white LED device fabricated by using BLASO:0.06Ce3+ as the green phosphor exhibits good optical performance with Ra = 88.5, CCT = 3562 K and CIE1931 chromaticity coordinates as (x = 0.4041, y = 0.3951). The results indicate that BLASO:0.06Ce3+ phosphor has strong potential applications in developing high color rendering, thermally stable, warm-white LEDs.

BACKGROUND Enhanced Recovery After Surgery (ERAS) programs can optimize clinical outcomes and have been widely used across multiple specialties, but a personalized prediction model involving ERAS for the prognosis of gastric cancer is lacking. MATERIAL AND METHODS We retrospectively collected clinical data on 725 gastric cancer patients within ERAS who underwent curative gastric resection in the Affiliated Hospital of Qingdao University from 2007 to 2014. Kaplan-Meier method, log-rank test, and Cox proportional risk model were used to determine the independent prognostic factors of patients. The accuracy of model was evaluated by C-index, calibration curve, and Decision Curve Analysis (DCA), and the receiver operator characteristic (ROC) curve was used to compare the nomogram model with the predictive value of TNM staging system. RESULTS The 5-year overall survival (OS) of 725 patients within ERAS was 72.5%. Age at diagnosis, T stage, N stage, and postoperative complications were determined to be independent factors affecting the prognosis of patients within ERAS, and nomogram model was constructed. The C-index of the training group was 0.809 and that of the verification group was 0.804; the calibration curves and DCA of the 2 groups showed good accuracy. Through verification, we found that, compared with the TNM staging assessment method, the nomogram model was more accurate in predicting the prognosis of gastric cancer. CONCLUSIONS This study identified factors affecting the prognosis of patients with gastric cancer, and we constructed the first prognostic nomogram model in ERAS mode to facilitate postoperative personalized prognostic evaluation.

A 24 GHz FMCW generator based on ADPLL was implemented in this work. Two-point modulation technology was used to achieve high sweep linearity. Meanwhile, a floating shield distributed metal capacitor bank was proposed to provide high frequency-sweep linearity DCO. By using these technologies, the FMCW generator’s frequency error can be controlled as small as 60 kHzrms when 180 MHz frequency was swept in 1.3 ms. High speed part of the FMCW generator was fabricated in 65 nm CMOS technology and the low speed digital part was implemented on FPGA. Power consumption of the chip excluding IO buffers is 29 mW.

This article proposes a tapped capacitor network for low-noise amplifier LNA input matching which can provide much broader bandwidth than traditional ones. According to the design, the implemented LNA can realize noise match and power match simultaneously, which will broaden LNA's bandwidth without introducing larger noise than traditional ones. In addition, input pad parasitic capacitance can be absorbed by the network. Then a k-band LNA with the matching network designed in 65 nm CMOS technology is shown to demonstrate the performance of the matching network. The tested results show that frequency band of S11 less than -10 dB is about 17 GHz and minimum NF is about 3.4 dB. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:146-153, 2015.

Farmland fragmentation is a land use pattern contrary to land formula management. It would lead to farmland's shrinking and decentralization, and reduce the output efficiency. Carrying out spatial evaluation of farmland fragmentation is the premise and foundation of improving the land use efficiency. The paper selected Chaohu Basin as the research object, regarded 3km size grid as research unit, constructed farmland fragmentation evaluation index system based on landscape indices, and calculated each grid's farmland fragmentation using entire-array-polygon indicator method. The results show that: The area of Chaohu Basin is 19785 km2, it is divided into 2326 grids by 3km size grid. Farmland accounting for about 57% of the total area distributes in 2238 grids, which is a wide range. The space difference of farmland fragmentation in Chaohu Basin is significant. The proportion of non-fragmentation region (603 grids) is 26.94%. They mainly concentrate in the northwestern and the eastern. Slight fragmentation region (662 grids) occupies 29.58%. They scattered in the whole basin; Moderate fragmentation region (663 grids) occupies 29.62%. They mainly distributes in four districts and the surrounding area of Hefei City; Severe fragmentation region (310 grids) which has the smallest percentage about 13.85%, mainly distributes in the southwestern mountainous area of the basin. Then, there were three policy recommendations being put forward, such as vigorously prompting the development of modern agriculture, promoting the development of characteristic agriculture and forestry, weighing the construction land and the farmland. By establishing the reasonable evaluation system, measuring farmland fragmentation of Chaohu Basin and analyzing the cause of this phenomenon, we can provide recommendations for Chaohu Basin's land use and land regulation. It's beneficial for improving farmland use efficiency.

Three-dimensional computer-aided design (3D-CAD) systems that integrate critical path method (CPM) algorithms, commonly referred to as four-dimensional computer-aided design (4D-CAD), have received a high level of interest over the past few years due to the insight they offer into constructability and feasibility analysis. This paper outlines an approach that facilitates this modeling method through integration between a commercial 3D-CAD software package and a discrete-event simulation tool. This approach employs a product-based modeling method that integrates simulation models with CAD drawings to provide real-time analysis and improved model accuracy in modeling construction operations. By integrating with 3D-CAD drawings, the models require much less data entry and provide a much higher degree of accuracy. Additionally, during the course of a project, resource and time consumption data can be collected and used to continually update the model, minimizing the use of assumptions and generalized data. This paper provides a short background and literature review to contextualize the problem statement, describes the product atomic component (PAC) used to integrate 3D-CAD and the simulation model, outlines some of the implementation issues in a simulation context, and presents a prototype system with an example application for an earthmoving project.Key words: 4D-CAD, CPM, product atomic component, simulation modeling, integration, earthmoving.

The land subsidence caused by underground coal mining can lead to topographic change and cause a series of environmental problems such as soil erosion and vegetation degradation, etc. Research on the effects of soil erosion is of great significance to the ecological restoration and environmental protection of mining areas. This paper selected the Bulianta coal mine in Inner Mongolia as a research area. Based on GIS/RS technology, the change in the spatial patterns of soil erosion in the study area were quantitatively evaluated using the rule of mining subsidence and the Universal Soil Loss Equation (USLE). The results show that underground coal mining has a significant effect on terrain by changing the slope length and slope steepness (LS), vegetation growth was also affected by a trend of overall reduction. In general, soil erosion in the Bulianta mining area generally showed an increasing trend from pre-mining topography to surface subsidence after mining, both from the perspective of soil erosion area and the perspective of soil erosion quantity.

Computer simulation has been successfully implemented in the area of construction management. However, this success has generally been limited to the academic arena with the industry lagging far behind. This failure is partly due to the inherent complexity of general simulators and their inability to abstract the underlying modeling fundamentals. Special purpose simulation (SPS) is a framework developed to address the stated drawbacks by focusing on the needs of the construction practitioner. The idea is to build modeling environments tailored to the specific requirements of a given industry domain. This paper presents the development and implementation of a construction dewatering analysis framework based on the ideas of SPS. Object-oriented design and graphical user interfaces are used in the development of an abstraction layer between a steady state hydrological model and the user. The integration capability of the framework are then presented by constructing an optimization module and linking it to the main modeling environment. A case study is provided to demonstrate the usefulness, intuitiveness, and validity of the framework.Key words: simulation, special purpose simulation, construction dewatering, optimization, computer applications.

A novel single-ended traveling wave fault location method applicable to the distribution network with multiple branches is presented in this paper. The method only depends on the arrival times of the initial aerial-mode and zero-mode travelling wave, and it is not affected by structure of a distribution system itself. Therefore, good results can be achieved for precise fault locating in multi-source and multisource distribution networks. Furthermore, the impacts of different factors on the fault location accuracy are investigated. The feasibility and effectiveness of the presented method is verified by PSCAD/EMTDC simulation results.

The selection of the faulty feeder in the case of single phase-to-earth fault in a Neutral Un-effectively Grounded System (NUGS) has been one of the conventional problems of distribution network. The compensation method is introduced to highlight the difference of the zero-sequence admittances between the faulted feeder and the sound feeder. In this way, the setting of the criterion becomes feasible. The on-site requirement to the protection is also involved in this paper. A variety of simulation tests were carried out by virtue of ATP software. The results demonstrate that this algorithm is immune to the variation of network structures and parameters, fault conditions, and fault resistance etc. The successful rate of feeder selection is proved to be improved to a great extent.

Although single phase to ground fault location in non-solid grounded networks has been studied for many years and a lot of research has been done, yet adequate solution for direct fault location of radial distribution network hasn't been made, especially for the distribution network with the neutral point grounded via arc suppression coil. Involvement of the arc suppression coil may decrease short-circuit current, but the difficulty of finding fault location is increased. The key problem of non-solid single-phase to ground fault location is to solve the fault location of distribution network with the neutral point grounding via arc suppression coil. This paper will analyse line capacitive current distribution of isolated neutral point and neutral point grounded via arc suppression coil and propose the concept of per-unit zero sequence current method. Equipartition principle of zero sequence current is utilized to locate fault section of the distribution system. Simulation tests to verify the effectiveness of this method have been made as well.

This paper presents a 20Gb/s Limiting Amplifier (LA) with the active interleaving feedback technique both to broaden the bandwidth and achieve flatness response. The LA includes an input match and DC offset cancellation (DCOC), a four-stage 3rd order amplifier core and an output buffer for test. Simulated in the 65nm CMOS technology, the LA exhibits a voltage gain of 38.5dB, a 3-dB bandwidth of 18GHz and an integrated input noise of 0.56mV with the area of only 0.45 × 0.25 mm2. The chip excluding buffer is supplied by 1.2V VDD and consumes DC power of 61mW.

A low-power, high linearity and wideband passive mixer for SDR is presented The passive mixer employs the improved current-reuse Gm stage, combines source degeneration with MGTR to extend the linearity region while enhance the IIP3 performance Measured results show the design achieves a good linearity even though the power of input RF signal is up to -14dBm (Vpp is about 160mV, consider the balun's voltage gain and insert loss). The passive mixer achieves 10.7-13.8 dBm IIP3, IIP2 > 44dB, and 13.7dB NF under 13dB Max conversion gain at 900MHz. Implemented in 65nm CMOS process, the mixer core die area is 0.2mm2, and consumes 6.7mA from a 1.2V supply.

A scheme for complex-valued acquisition of the diffraction imaging with quasimonochromatic incoherent light is theoretically proposed. The main idea is to project the real and the imaginary parts of a Fraunhofer diffraction field on intensity distributions, respectively, with the use of a {pi}/2 phase-changing plate. The whole procedure is iterative algorithm free and needs no a priori knowledge of an arbitrary object. A numerical experiment and a quantitative confirmation are also given. To our knowledge, it was the first physical proposal for the complex-valued acquisition of a diffraction imaging by two-dimensional coherent patterns with thermal illumination.

The strategies for controlling resulfurization in a converter steelmaking process were clarified to produce pipeline steel with the KR–LD–RH–CC route, and the influence factors of resulfurization were investigated based on the industrial data and theoretical analysis. The results show that KR slag and lime account for the largest proportion of the sulfur-bearing materials of the sulfur in the converter. The influence of sulfur fluctuation in lime on the resulfurization was also significant. The removal ability of KR slag was greater by using a crawler loader than by using a slag-dredger. The steel resulfurization can be more effectively restrained by a conventional converter process than by a duplex converter process. Moreover, the rate-limiting step of the resulfurization in the converter is considered to be the mass transfer of sulfur from the interface toward the bulk of the slag phase, and slag with doubly saturated MgO and 2CaO•SiO2 was proposed to restrain the rate of resulfurization without changing the dephosphorization rate. The industrial experimental results show that the sulfur content of the steel before tapping into the ladle can be controlled at 0.002% to 0.003% when employing the above controlling strategies.

When conducting the wind power (WP) planning, it is very important for electric power companies to evaluate the penetration limit of the grid-accommodable WP. This paper proposes a probabilistic method for determining grid-accommodable WP capacity based on the multiscenario analysis. Typical power system operation scenarios are generated from the combination of different WP scenarios and demand scenarios. A power system operation simulation model is proposed and implemented to the generated scenarios. The operation results are further used as the basis of the proposed probabilistic method. The validity and effectiveness of the new method are demonstrated in two cases, i.e., the IEEE 39-bus test system and a real large power system in China, respectively.