Anomalies of upper critical field in the spinel superconductor LiTi2_2O4−δ_{4-\delta}

High-field electrical transport and point-contact tunneling spectroscopy were used to investigate superconducting properties of the unique spinel oxide, LiTi$_2$O$_{4-\delta}$ films with various oxygen content. We find that the upper critical field $B_\mathrm{c2}$ gradually increases as more oxygen impurities are brought into the samples by carefully tuning the deposition atmosphere. It is striking that although the superconducting transition temperature and energy gap are almost unchanged, an astonishing isotropic $B_\mathrm{c2}$ up to $\sim$ 26 Tesla is observed in oxygen-rich sample, which is doubled compared to the anoxic sample and breaks the Pauli limit. Such anomalies of $B_\mathrm{c2}$ were rarely reported in other three dimensional superconductors. Combined with all the anomalies, three dimensional spin-orbit interaction induced by tiny oxygen impurities is naturally proposed to account for the remarkable enhancement of $B_\mathrm{c2}$ in oxygen-rich LiTi$_2$O$_{4-\delta}$ films. Such mechanism could be general and therefore provides ideas for optimizing practical superconductors with higher $B_\mathrm{c2}$

Anomalies of upper critical field in the spinel superconductor LiTi2 O4-δ

© 2019 American Physical Society. High-field electrical transport and point-contact tunneling spectroscopy are used to investigate superconducting properties of spinel oxide LiTi2O4-δ films with various oxygen contents. It is striking that although the superconducting transition temperature and energy gap are almost unchanged, an isotropic upper critical field Bc2 up to 26.0 T is observed in the oxygen-rich sample, which is more than twice the Bc2 of 11.3 T in the anoxic one. The change of the dominating pair-breaking mechanism from the orbital effect to the spin flip at Bc2 is achieved by tuning oxygen contents, which can be explained by the appearance of small Fermi pockets due to extra oxygen. Our paper provides deep understanding of the intrinsic relation between Bc2 and the complex Fermi surface, and contributes a promising way to enhance Bc2 for practical superconductors

Lessons learned practices in the UAE construction industry

The failure of learning from our mistakes or those of others, has generated unnecessary waste of time and costs, in the construction industry, due to its project based, fragmented and unstable nature. Lessons Learned, as an important way of improving projects performance, is analyzed in this study, with the aim to explore the current practice of Lessons Learned in the UAE construction industry. A literature review has revealed what “Lessons Learned” is under different contexts, and focused on various factors influencing a Lessons Learned Programme. The research method of a series of structured interviews, followed by an on line questionnaire, is adopted in this study. It was found that although the concept of Lessons Learned is quite familiar by most of professionals in the project management in the UAE construction industry, Lessons Learned practice is mainly performed in an informal way (individually or ad hoc). As for barriers for Lessons Learned practice, Culture factors, such as “Afraid to be blamed for mistakes” and “lack of learning culture” (1st and 2nd rank) influence significantly in Lessons Learned practice. It is also found that a formal lessons learned programme does exist in some organizations. However, with the lack of a dedicated Lessons Learned repository and Lessons Learnt system, Lessons Learned has yet a long way to reach its potential

Social risk factors of transportation PPP projects in China: A sustainable development perspective

Public-private partnerships (PPPs) have become increasingly important in improving the sustainability of society in China, with transportation being the largest investment area. However, the Social Risk Factors (SRFs) of transportation PPPs in China, which serve as a useful tool for distinguishing strengths and weaknesses for effective social risk management (SRM), have not been clearly identified. A conceptual model including 3 risk dimensions and 15 SRFs was proposed to mitigate social risks and improve the social sustainability of transportation PPP projects. A questionnaire survey conducted to investigate stakeholders’ opinions on the proposed SRFs demonstrated that all the SRFs were important. The SRFs can be used to evaluate social risks from economic, environmental, and social dimensions. Confirmatory factor analysis (CFA) verified the classification of the SRFs and indicated that all the risk dimensions contributed to social risks. The social and environmental impacts on social sustainability may contribute more to the generation of social risks. Furthermore, the concept of people-first PPPs was proposed to reduce social risks from the perspective of different stakeholders, with the interactions among different stakeholders being prioritized. The identified SRFs and their relationships can improve our understanding of SRM in the delivery of social sustainability and improve social resilience

Partnering research within the construction industry (1990-2018): A scientometric review

This paper performs a scientometric review of the intellectual structure and evolutionary patterns of partnering research within construction industry (CI). Based on 788 bibliographic records retrieved from Scopus published in 1990-2018, CiteSpace is used to facilitate the scientometric analysis and visualisation of construction partnering research. The results show that: 1) the UK, the USA, and China are the primary origins of construction partnering research, and this domain typically arises from inter-organisation collaboration in business management; 2) research topics covered in the field concentrate on partnering application and performance, trust, partnering mechanism to strengthen performance, development of partnering model, critical success factors, reviews of the development of partnering research, and construction innovation promoted by partnering; 3) strategic partnering should be emphasised through supply chain integration in the CI. This paper provides an in-depth understanding of construction partnering research and inspires further inter-organisation collaboration within the CI

454 sequencing data

454 sequencing data from ancestral(ANC) and evolved yeast populations - base sequences in fasta format along with corresponding base quality score

Entry mode taxonomy and choice of Chinese international construction companies

Along with China’s national strategy “One Belt, One Road,” an increasing number of Chinese construction companies has ventured or will venture into the global market. The choice of entry mode is crucial for companies when going abroad. The objectives of this study are to (1) establish a systematic classification of the entry modes used in the international engineering field, and (2) identify and analyze the factors that influence the entry-mode choices of Chinese international construction companies (ICCs). Based on a literature review and a survey of 264 cases, a two-dimensional (2D) taxonomy model of the entry modes was established, and six factors significantly impact the choice of entry mode for Chinese ICCs were identified. The findings may help Chinese ICCs learn more about the choices available to them, the factors that influence these choices, and the way these factors influence their choices when venturing abroad

Receive Quadrature Reflecting Modulation for RIS-Empowered Wireless Communications

In this paper, we propose a novel reconfigurable intelligent surface (RIS)-based modulation scheme, named RIS-aided receive quadrature reflecting modulation (RIS-RQRM), by resorting to the concept of spatial modulation. In RIS-RQRM, the whole RIS is virtually partitioned into two halves to create signals with only in-phase (I-) and quadrature (Q-) components, respectively, and each half forms a beam to a receive antenna whose index carries the bit information. Furthermore, we design a low-complexity and non-coherent detector for RIS-RQRM, which measures the maximum power and polarities of the I- and Q- components of the received signals. Approximate bit error rate (BER) expressions are derived for RIS-RQRM over Rician fading channels. Simulation results show that RIS-RQRM outperforms the existing counterpart without I/Q index modulation in terms of BER in the low signal-to-noise ratio region

A Kernel-based Real-time Adaptive Dynamic Programming Method for Economic Household Energy Systems

Modern home energy management systems (HEMS) have great flexibility of energy consumption for customers, but at the same time, bear a range of problems, such as the high system complexity, uncertainty and time-varying nature of load consumptions, and renewable sources generation. This has brought great challenges for the real-time control. To solve these problems, we propose a HEMS that integrates a kernel-based real-time adaptive dynamic programming (K-RT-ADP) with a new pre-processing short-term prediction technique. For the pre-processing short-term prediction, we propose a Gated Recurrent Unit-Bidirectional Encoder Representations from the Transformer (GRU-BERT) model to improve the forecasting accuracy of electrical loads and renewable energy generation. In particular, we classify household appliances into the temperature-sensitive loads, human activity sensitive loads and insensitive/constant loads. The GRU-BERT model can incorporate weather and human activity information to predict load consumption and solar generation. For real-time control, we propose and employ the K-RT-ADP HEMS based on the GRU-BERT prediction algorithm. The objective of the K-RT-ADP HEMS is to minimize the electricity cost and maximize the solar energy utilization. To enhance the nonlinear approximation ability and generalization ability of the ADP algorithm, the K-RT-ADP algorithm leverages kernel mapping instead of neural networks. Hardware-in-the-loop (HIL) experiments demonstrate the superiority of the proposed K-RT-ADP HEMS over the traditional ADP control through comparison

Spatio-temporal variation of evapotranspiration and its linkage with environmental factors in the largest freshwater lake wetland in China

Study region Poyang lake wetland Study focus Evapotranspiration (ET) is a critical parameter in the hydrologic and energy budget, and it is important for understanding spatio-temporal variations in ET in large lake wetlands. Monthly ET in the Poyang Lake wetland during 2008–2017 was estimated by the remote sensing ET retrieval model based on a Nonparametric approach (RS-NP). And the spatio-temporal variation of ET and the influencing factors were analyzed. New hydrological insights for the region The validation revealed the usefulness of the RS-NP model in a moist region and yielded a relative error of 6 % (12 %) in the wet (dry) season. Temporally, the average yearly ET was 884 mm with ET/P (precipitation) of 55 %− 65 %. The monthly ET/P ratio increased significantly from 40 %− 50 % from January to May to 90 %− 130 % from July to October. ET in June was lower by over 20 % than that in May and July with the lowest ET/P value (33 %). Spatially, relatively larger and lower ET occurred in the northern and southern parts, respectively. The main factors affecting ET variability were downwelling shortwave radiation (∼2/3 contribution) and water area (∼1/3 contribution) at the monthly scale. Precipitation and surface temperature dominantly controlled the hysteresis effects with a lag of one month and regulated LE monthly variations. This study improves our understanding of complicated water-atmosphere interactions and their linkages with environmental factors in large lake systems.</p