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The physical and geochemical character of the post‐depositional changes present in the Early‐Middle Jurassic carbonate‐dominated units (Samana Suk, Shinawari, Chiltan and Loralai formations) of the Indus Basin, Pakistan have been addressed. The study is based on 11 sections along a N‐S transect on the western margin of the Indian Plate to provide an insight into the nature of cementation and dolomitization behavior by using an integrated petrographic and geochemical analysis. The carbonates located in the northern proximity are dominated by the eogenetic signatures of hardgrounds, biogenic micritization, and iron‐containing burrows. The pattern and yellowish‐brown coloration of the burrows is distinct, and shows a positive relationship with the Fe, Si, Al, K, Mn concentrations, and meteoric phase. The transition from the Early to Middle Jurassic is marked by a correspondent increase in the dolomitization and bioturbation but its intensity decreases from north to the south. The packing index and marine phreatic environments generally increase towards the south. The planar‐s to planar‐e protodolomite and dolomite proper have particularly targeted the micritic facies and allochems, courtesy of retaining high‐magnesian calcite waters, and the geochemical analysis also reveals some dedolomitization, associated with sequence boundaries. The pore occluding cements of the Samana Suk and Chiltan formations are Fe deficient and have low Sr and Mn levels, as compared to the Shinawari Formation. The latter has an elevated concentration of Fe, Mg, Si, Al, Sr, Mn, and the Fe + Mn versus Sr relationship and Mn* values suggest that cementation dominantly occurred in the oxic‐dysoxic zones of sub‐tropical climate. [ABSTRACT FROM AUTHOR]

Flowing and stagnant zones coexist in central discharging flat-bottomed packed beds. Continuum based approach has been widely used to predict the flow characteristics. In particular, potential flow (PF) model was often used due to its simplicity but has a difficulty in predicting the stagnant zone. In our previous work, a novel PF model was proposed to overcome the difficulty. However, due to the assumption of constant flow resistance coefficient, the local velocity effect and typical non-linear flow mechanism have not been addressed. In this work, the concepts of linear resistance (LR) and constant resistance (CR) flows were proposed first based on the effects of discharging velocity. Then, the local velocity effect on the flow resistance was obtained by connecting the resistances of LR and CR flows in parallel. Further, the effects of LR and CR flows were discussed and validated by recorded data in 2D central discharging packed beds. The improved PF model enables to capture the funnel flow variations under different conditions and develop further understanding of granular flow in the flowing and stagnant zones. [ABSTRACT FROM AUTHOR]

Current barriers hindering data-driven discoveries in deep-time Earth (DE) include: substantial volumes of DE data are not digitized; many DE databases do not adhere to FAIR (findable, accessible, interoperable and reusable) principles; we lack a systematic knowledge graph for DE; existing DE databases are geographically heterogeneous; a significant fraction of DE data is not in open-access formats; tailored tools are needed. These challenges motivate the Deep-Time Digital Earth (DDE) program initiated by the International Union of Geological Sciences and developed in cooperation with national geological surveys, professional associations, academic institutions and scientists around the world. DDE's mission is to build on previous research to develop a systematic DE knowledge graph, a FAIR data infrastructure that links existing databases and makes dark data visible, and tailored tools for DE data, which are universally accessible. DDE aims to harmonize DE data, share global geoscience knowledge and facilitate data-driven discovery in the understanding of Earth's evolution. [ABSTRACT FROM AUTHOR]

An optimal planning model of the sectional switch and tie line for the distribution network is proposed considering the tradeoff between the system reliability and economy. First, the fault incidence matrices are established for the distribution network, and the explicit analytical expression of the system reliability index is realized by the algebraic operation of the fault incidence matrices and fault parameter vectors. Then, the 0–1 integer quadratically constrained optimization model is established for the sectional switch configuration considering the capacity constraint of the tie line. Finally, the sectional switches and tie lines are optimized jointly to ensure the economic investment and maximize the system reliability. The distribution network in Taiwan Power Company is used to verify the applicability of the proposed optimization method. Compared with the intelligent optimization algorithm, the mathematical programming method in this paper can always find the global optimal switch configuration quickly. In addition, the influence of the tie line capacity constraints on the sectional switch configuration is also considered, which can provide practical reference for the power network planners in the optimization design of the distribution network. [ABSTRACT FROM AUTHOR]

• A generalized integer linear programming model of the PMU placement is proposed. • Topology changes are considered to guarantee the observability with multiple topologies. • The effects of existing measurements and their relevance are covered. Distribution networks usually have a meshed structure but are operated radially to improve the operating efficiency and ensure the power supply under an emergency situation. It is of great significance to guarantee the observability of the entire system under the topology changes in operation. This paper proposes an optimal placement method of phasor measurement unit (PMU) for distribution networks. A generalized binary integer linear programming (ILP) model for PMU placement is proposed. The changes in topology are considered to guarantee the observability under any possible operation mode. The existence of zero injection nodes (ZINs), the existing measurements, and their relevance are also covered in the proposed method to reduce the installed PMU number. The objective of the ILP problem is weighted by the degree of the corresponding node to obtain a scheme with higher measurement redundancy. The correctness and effectiveness of the proposed method are verified via case studies on the IEEE 33-node test feeder, PG&E 69-node test feeder, and a medium voltage distribution network in Southern China. [ABSTRACT FROM AUTHOR]

• A novel PMU-based equivalent model for voltage sensitivity estimation is proposed. • The simplified observable network is obtained with PMUs configured arbitrarily. • Multitime slots of PMU measurements are used to estimate equivalent parameters. • A robust method is exploited to handle the noise and bad data in measurements. The access and application of phasor measurement units (PMUs) in distribution networks highly improve the system observability and further enhance the performance of operation control and energy management. A novel PMU-based estimation method of voltage-to-power sensitivity via network equivalent is proposed for distribution systems. An equivalent model is introduced to simplify the PMU-unobservable parts of the distribution network. The equivalent parameters are estimated with the PMU measurements on both sides. The original PMU-unobservable distribution network is simplified into a completely observable network with an arbitrary configuration of PMUs. The maximum correntropy Kalman filter (MCKF) is exploited in parameter estimation to handle the noise and bad data within the PMU measurements. The voltage-to-power sensitivity of the simplified system is then calculated according to the estimation of the equivalent network parameters. Case studies on the IEEE 33-node and the PG&E 69-node test feeders verify the correctness and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Highlights • An analytical framework for quantifying the flexibility of ADNs was proposed. • Flexibility of network transmission was analysed with the limits of physical network. • The benefits of controllable resources for flexibility improvement were explored. Abstract With the integration of high shares of distributed generators (DGs), it is increasingly difficult to cope with the various uncertainties and puts forward higher requirements for the operational flexibility in active distribution networks (ADNs). Controllability of ADNs has been significantly improved by the application of energy storage and power electronic devices. However, due to the difficulties in effective coordination of various controllable resources, the controllability cannot be fully translated into the system flexibility. In this paper, an analytical framework for quantifying the flexibility of ADNs is proposed, including the quantification of node flexibility, the matching of system flexibility, and the flexibility of network transmission. The proposed framework provides a novel perspective of flexibility to reinterpret operation issues of distribution networks. As the power imbalance and voltage deviation are even more severe caused by the high shares of DG integration, the indexes of flexibility from magnitude, frequency and intensity dimensions are deteriorated in ADNs operation. Through the spatial and temporal regulation of power flow, various controllable devices, such as soft open points (SOPs) and energy storage system (ESS), can effectively mitigate the power imbalance and voltage deviation to improve the indexes of system flexibility. Thus, under the unified analytical framework, the potential benefits of system controllability are fully utilized to provide effective countermeasures for the flexible operation of ADNs. Finally, case studies are performed on the modified IEEE 33-node system to quantify the operational flexibility of ADNs and verify the flexibility enhancement brought by controllable resources. [ABSTRACT FROM AUTHOR]

Abstract Potential flow (PF) model exhibits some advantages to simulate granular flow in industrial packed beds such as an iron-making blast furnace. To change the status of solving PF equations in the flowing zone, based on the difference analysis between PF and actual flow, the components of granular flow resistance were confirmed, and a novel potential flow (NPF) model for the flow of packed particles was established. The obvious difference from the PF model is that the NPF model can simultaneously predict the stagnant zone and the distribution of velocities in the flowing zone. The stagnant zone or the flowing zone calculated with NPF model under certain boundary conditions is only determined by a dimensionless parameter group R ⁎ . R ⁎ has a clear physical meaning, so it's easy to decide the effect on the distribution of stagnant zone and granular flow velocities. Furthermore, NPF model was validated by experimental data obtained with a two-dimensional flat-bottomed packed bed with centric discharge. Predicted results respectively by PF and NPF models were also compared. Graphical abstract Unlabelled Image Highlights • Novel potential flow model for granular flow in packed bed was put forward. • The model results are only decided by a dimensionless group at certain conditions. • The stagnant zone and the flowing zone could be simultaneously predicted. • Predicted results accord quite well with the experimental results. [ABSTRACT FROM AUTHOR]

Highlights • A day-ahead scheduling strategy is proposed with detailed device modeling. • The effects of multiple thermal storage devices on flexibility are fully utilized. • The unit commitment constraints in practical operation are well considered. • The optimal scheduling model is transformed into a MILP formulation by linearization. Abstract The operation of community integrated energy systems (CIESs) is challenging because it is necessary to couple energy production, conversion and consumption on the end-user side. Multiple energy demands need to be fed simultaneously with the goal of economy and reliability. This paper formulates the optimal scheduling problem based on a real community integrated energy system in China. The system has multiple chillers (i.e. three ground source heat pumps, two conventional water-cooled chillers and two double-duty chillers) and two types of thermal storage devices (i.e. two cold water tanks and an ice-storage tank). Based on detailed device modeling, a community integrated energy system operation strategy considering unit commitment is proposed, and then is transformed into a mixed-integer linear programming model by linearization of nonlinear items. Case studies are conducted based on the data for a typical day in summer. The results show that the proposed strategy can utilize the flexibility of the energy storage devices and realize an economic and reliable operation of the community integrated energy system by coordinating various energy devices. The strategy can also reduce the startup/shutdown frequency of chillers significantly. [ABSTRACT FROM AUTHOR]

Highlights • A distributed network loss optimization approach is present to increase energy utilization. • A fully distributed voltage control method is proposed. • A topology simplification method with DPMU data at controllable DGs/loads is proposed. • The coordinated control system is based on incomplete measurements. Abstract This paper explores a distributed coordinated control algorithm for active distribution networks (ADNs) based on measurements of distribution phasor measurement units (DPMUs) that are only installed at a portion of network nodes. First of all, a network topology simplification method is proposed to deal with the lack of impedance and power information in ADNs. Specifically, sub-networks with unknown impedance and power information are transformed to simplified networks with known equivalent parameters that are derived from the measurements of DPMUs at the sub-network boundaries. After that, a fully distributed control strategy utilizing a multiple agent system (MAS) is employed to control voltage during voltage excursions in ADNs, and to optimize network losses if no voltage excursions occur. MAS achieves global voltage control through distributed decision-making according to the voltage-power sensitivities that are calculated by each agent based on local and neighbourhood measurements. MAS balances reactive power locally to reduce network active power losses. The convergence of the proposed distributed voltage control method is proved. Finally, the feasibility and effectiveness of the proposed method has been demonstrated on a modified IEEE 33-bus system. [ABSTRACT FROM AUTHOR]

A fast reliability calculation method based on the fault incidence matrix (FIM) for the complex distribution system is proposed in this paper. First, the M-segment-N-tie-switch (MSNT) reliability calculation unit for the complex distribution network is established and the power supply path matrix is obtained by inversing the node branch incidence matrix of the MSNT unit. Then, three types of FIMs are constructed considering the influence type of each fault event on the load points. Finally, the system reliability indexes are calculated through the algebraic operation between the FIMs and the fault event parameter vectors. The accuracy and the efficiency of this method are verified using the IEEE RBTS bus-6 system. The reliability evaluation method proposed in this paper avoids complicated fault event enumeration and repetitive fault influence range searching, thus, saves the computation time greatly. And more importantly, the analytical expression of the reliability indexes in the matrix form can clearly show the influence of each fault event on each load interruption. So, it is convenient for the reliability sensitivity analysis and helpful for the operator with the reliability improvement planning. [ABSTRACT FROM AUTHOR]

We present new geochemistry, geochronology, whole-rock Sr-Nd-Pb, and zircon Hf isotopic data from the Zhongba pluton in the western part of the Gangdese magmatic belt (GMB) and discuss its melt evolution within the collisional tectonic framework of southern Tibet. Our U-Pb zircon dating of the Zhongba plutonic rocks has constrained the timing of their emplacement at 38 Ma. The Zhongba granitoids are enriched in light rare earth elements, large-ion lithophile elements, and Pb and are depleted in high-field-strength elements. They show enriched Sr isotopes, low εNd(t) values, and fairly radiogenic Pb isotopic signatures. They have negative zircon εHf(t) values and ancient crustal model ages of 1483–1180 Ma. These geochemical and isotopic characteristics, combined with the literature data, suggest mixing of different magma types, derived from partial melting of juvenile southern Lhasa crust and ancient Indian continental crust, to produce hybrid magmas of the Zhongba granitoids. We propose that asthenospheric upwelling caused by the breakoff of the northward-subducting Neotethyan oceanic lithosphere provided the heat and material flux to trigger partial melting of the overlying Lhasa arc lithosphere and subducted sediments of the ancient Indian crust. Similar geochemical and isotopic signatures of the coeval Kailas and Zedong granitoids within the GMB indicate that this slab breakoff–induced mid- to late Eocene magmatism was a syncollisional and orogen-parallel magmatic event. The Zhongba pluton and its contemporaneous equivalents thus provide the geochronological and isotopic evidence for the earliest melt flux derived from the subducted continental crust and sediments of India into the melt regime of Cenozoic magmatism in southern Tibet. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The real-time simulation framework for active distribution networks was built. • A multirate simulation method was proposed with high-accuracy and stability. • The detailed hardware design of the real-time simulator was presented. Abstract Real-time simulation of large-scale active distribution networks exhibiting a wide range of time-scales puts forward higher requirements for simulation accuracy and efficiency. This paper presents an extendable method and design for the real-time simulation of active distribution networks utilising high-performance hardware field programmable gate arrays. In the aspect of numerical algorithm, a high-accuracy and stable multirate simulation algorithm is proposed. The entire active distribution network is decoupled into different subsystems by their inherent time-scales and distinct time steps are used to solve the subsystems. Then root-matching method is adopted to form the exponential difference equations that represent the behaviours of the electric distribution network being modelled, which eliminates the truncation errors and thus provides a highly accurate time-domain solution. To handle the interface between the subsystems, a multirate interfacing method is proposed. The hardware design of the multirate interfaces is presented as well. With the multirate algorithm, a fully functional extendable real-time simulator based on field programmable gate arrays is designed and implemented. Two modified IEEE 33-node systems with photovoltaics and energy storage are simulated on the 4-field-programmable-gate-arrays-based real-time simulator. Simulation results are compared with the commercial simulation tool PSCAD/EMTDC to validate the correctness and effectiveness of the proposed method and design. [ABSTRACT FROM AUTHOR]

Highlights • A centralized parameter tuning model of local control curves was proposed for DGs. • The potential benefits of DG inverters were explored to realize voltage control. • A mixed-integer second-order cone programming (MISOCP) model was formulated. Abstract The increasing penetration of distributed generators (DGs) exacerbates the risk of voltage violations in active distribution networks (ADNs). The var capacity provided by DG inverters is a potential solution for voltage regulation. The conventional centralized control strategies limited by computation and communication burdens are difficult to meet the requirement of rapid voltage control. However, the local control strategies based on real-time measurements have a fast response to the frequent fluctuations of DG outputs. The performance of these local controllers depends on the tuning of the control parameters. This paper proposes a centralized-based method to determine the local voltage control strategies for DGs. A centralized parameter tuning model of control curves is built, in which Q - V and P curt - V curves of DG inverters are mathematically formulated based on piecewise linearization. The original mixed-integer nonlinear programming (MINLP) model is converted into an effectively solved mixed-integer second-order cone programming (MISOCP) model using convex relaxation. The potential benefits of DG inverters are explored to regulate both reactive and curtailed active power, based on local voltage measurements. Case studies on a modified PG&E 69-node distribution system are carried out to verify the effectiveness of the proposed method. Results show that power losses of ADNs are significantly reduced and voltage profiles are also improved. [ABSTRACT FROM AUTHOR]

There is an increasing awareness of resilience for active distribution networks (ADNs) as extreme fault conditions pose threats to the reliable operation of power supply. Islanding operation of ADNs with distributed generators (DGs) and energy storage system (ESS) can significantly serve the critical electricity demands and improve the power supply reliability. Considering the characteristics of DG, ESS and load, a time-series islanding partition model of ADNs is established based on soft open point (SOP). The proposed model exploits the benefits of operational flexibility provided by SOP to improve the level of load recovery. It further takes into account the coordination of the control strategies among regulation devices as well as the failure duration in island partition, while satisfying a variety of operational constraints. Specifically, a mixed-integer nonlinear programming (MINLP) is employed to solve the proposed model effectively. Finally, case studies on IEEE 33-node and IEEE 123-node test feeders verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

The lacustrine shale of deep Shahezi Formation in the Songliao basin has great gas potential, but its pore evolution, heterogeneity, and connectivity characteristics remain unclear. In this work, total organic carbon analysis, rock pyrolysis, X‐ray diffraction, field emission scanning electron microscopy, the particle and crack analysis system software, low‐temperature nitrogen adsorption experiment, fractal theory, high‐pressure mercury injection experiment and nuclear magnetic resonance experiment were used to study the Shahezi shale from Well SK‐2. The result indicated that the organic pores in Shahezi shale are not developed, and the intergranular and intragranular pores are mainly formed by illite‐dominated clay. As the burial depth increases, the pore size and slit‐shaped pores formed by clay decrease, and dissolved pores in the feldspar and carbonate minerals and dissolved fractures in the quartz increase. The pore evolution is affected by clay, compaction, and high‐temperature corrosion. Based on the pore structure characteristics reflected by the pore size distribution and pore structure parameters obtained by multiple experimental methods, the pore development and evolution are divided into three stages. During stage I and II, the pore heterogeneity of the shale reservoirs increases with the depth, the physical properties and pore connectivity deteriorate, but the gas‐bearing property is good. In stage III, the pore heterogeneity is the highest, its gas generation and storage capacity are low, but the increase of micro‐fractures makes pore connectivity and gas‐bearing better. [ABSTRACT FROM AUTHOR]

The early Aptian Selli Oceanic Anoxic Event 1a (ca 120 Ma) is a major Mesozoic episode of biotic, climatic, environmental and geochemical perturbations associated with the extensive burial of organic matter. Based on the new sedimentological, biostratigraphic and carbon‐isotope data from the Kazhdumi Intrashelf Basin, this study tracks the Oceanic Anoxic Event 1a‐associated perturbations along the north‐eastern margin of the Arabian Plate. The studied succession has five complete third‐order sequences with three facies associations: (i) deep open‐marine and intrashelf basin; (ii) shallow open‐marine mid‐ramp; and (iii) inner ramp. The Oceanic Anoxic Event 1a‐equivalent deposits include the former two facies associations – (i) and (ii) – and are 25 to 31 m thick, which corresponds to the accumulation rates of ca 1.9 to 3.1 cm kyr−1 (uncorrected for compaction) based on the 1.0 to 1.3 Myr duration of the event. The interval retained a high‐resolution record of carbon‐isotope and sea‐level fluctuations, which enables correlation across the Arabian Plate and Tethys. The Oceanic Anoxic Event 1a onset is marked by a biotic change from ostreid‐dominated shallow‐marine limestone with abundant foraminifera (Palorbitolina lenticularis and Choffatella decipiens) to dark grey deep‐water planktonic foraminifera‐rich and radiolaria‐rich limestone with chert and organic‐rich shale (Radiolarian Flood Zone). The upper oceanic anoxic event part of 1a is characterized by the shallowing‐upward, backstepping facies marking the return to a shallow open‐marine setting, albeit without recovery of the Palorbitolina–Choffatella association. Deep open‐marine deposition (Kazhdumi Tongue) was restored early during the Oceanic Anoxic Event 1a recovery in the latest early Aptian. A return to shallow open‐marine environments with Mesorbitolina‐rich limestone marks the beginning of the late Aptian, followed by a major sea‐level fall and karstification. This study resolves some of the uncertainties related to the order and timing of the events influencing the environmental disturbances across the eastern Arabian Plate during Oceanic Anoxic Event 1a and stresses the importance of shallow carbonate‐dominated intrashelf basins as faithful recorders of carbon‐isotope and sea‐level oscillations and palaeoenvironmental changes during global oceanic perturbations. [ABSTRACT FROM AUTHOR]

With the integration of high shares of distributed generators (DGs), both volatile DGs and demand-side resources make it increasingly difficult to cope with the various uncertainties and put forward a higher requirement for the operational flexibility in active distribution networks (ADNs). The highly integrated distribution-level power electronic devices represented by soft open point (SOP) significantly benefit the operation of ADNs. Due to the accurate and rapid power flow control provided by SOP, various flexible resources can be coordinated in the spatial and temporal aspects, which effectively increases the DG penetration of ADNs. In this paper, the multi-dimensional characteristics of distribution system flexibility are analysed and the maximum DG hosting capacity is adopted as the index to evaluate the flexibility brought by SOP. The flexibility evaluation model is further proposed to quantify the benefits of SOP-based flexible resources, such as conventional SOP, multi-terminal SOP and SOP with energy storage. Then, the original non-convex nonlinear model is converted into an effectively solved second-order cone programming (SOCP) model using convex relaxation. To tighten the deviation of convex relaxation to the predefined accuracy, a difference-of-convex programming (DCP)-based approach is developed to solve the proposed model. Finally, case studies are performed on the modified IEEE 33-node system to verify the effectiveness and efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

A CLTCL resonant dc-dc converter is proposed in this paper. Through the dual-transformer architecture, the resonant characteristic of the converter alters and contributes to a wide input voltage range and a greatly broadened output voltage range from zero to the nominal. The transformer leakage inductors also participate in the resonating process, which eliminates their side effects on the conversion performance. Moreover, a simple and effective design method for converters with multiple resonant components is used to guide the resonant parameter design with the assistance of the MATLAB program. Soft switching for both turn-on and turn-off processes of all the inverter and rectifier switches is acquired, and the proposed converter, therefore, achieves lower switching losses among a wide load scope. In the end, a 1-kW prototype with a peak efficiency of 97.3% is fabricated in the laboratory to verify the working principle and design effect of the CLTCL converter. [ABSTRACT FROM PUBLISHER]

In the face of unprecedented challenges in environmental sustainability and grid resiliency, there is an increasingly held consensus regarding the adoption of distributed and renewable energy resources such as microgrids (MGs).This study explores a decentralised voltage control method based on a multi‐agent system (MAS) with built‐in incentives for various participants in distribution networks (DNs). Without an arbitration agent in MAS, peer agents calculate voltage sensitivities via agents' local and neighbourhood measurements in a fully decentralised approach. An incentive mechanism is designed to motivate the MGs in DNs to participate in voltage control with guaranteed subsidies to ensure individual rationality. On the basis of the voltage sensitivities, each MG decides its strategy by managing energy suppliers and consumers to maximise its own profit while providing the ancillary service of voltage control. The strategy converges through an iterative process to a Nash equilibrium which maximises each MG's profit. In addition, an incomplete information game is applied to ensure the privacy of MGs. Furthermore, the feasibility and effectiveness of the proposed voltage control method is demonstrated on a modified IEEE 33‐bus system, and finally the existence of a Nash equilibrium in the game model is proved in the Appendix. [ABSTRACT FROM AUTHOR]

With the increasing penetration of renewables, microgrid integration has been considered as one of the most promising approaches to enhance the utilizations of various types of energy resources in smart distribution systems. In the near future, with the higher levels of intermittent renewables are envisaged, the distribution network operators will face significant challenges to the control and operation of distribution networks dispersedly. Consequently, the development of effective and motivating ancillary service schemes in a decentralized way for executing real-time control and reducing calculation and communication burden is still in its infancy and needs to be researched. To address this issue, this paper explores an optimal voltage regulation method with the participants of multi-microgrids based on multiple agent systems. Without an arbitration agent, peer agents in the multiple agent system calculate voltage sensitivities by local and neighbourhood measurements only. In this paper, a bi-level game model is proposed for voltage control process. In the upper-level, the distribution network operator searches the reasonable incentive mechanism based on the Stackelberg game. In the lower-level, microgrids make voltage control strategies autonomously based on a static game among microgrids. In the proposed method, microgrids participate in voltage control in distribution networks as ancillary service providers while maximizing their own profits. Meanwhile, the distribution network operator reduces the infrastructure reinforcement and avoids unnecessary renewable energy curtailment. Finally, the feasibility and effectiveness of the proposed method has been demonstrated on a modified IEEE 33-bus system. [ABSTRACT FROM AUTHOR]

The integration of distributed generators (DGs) exacerbates the feeder power flow fluctuation and load unbalanced condition in active distribution networks (ADNs). The unbalanced feeder load causes inefficient use of network assets and network congestion during system operation. The flexible interconnection based on the multi-terminal soft open point (SOP) significantly benefits the operation of ADNs. The multi-terminal SOP, which is a controllable power electronic device installed to replace the normally open point, provides accurate active and reactive power flow control to enable the flexible connection of feeders. An enhanced SOCP-based method for feeder load balancing using the multi-terminal SOP is proposed in this paper. By regulating the operation of the multi-terminal SOP, the proposed method can mitigate the unbalanced condition of feeder load and simultaneously reduce the power losses of ADNs. Then, the original non-convex model is converted into a second-order cone programming (SOCP) model using convex relaxation. To tighten the SOCP relaxation and improve the computation efficiency, an enhanced SOCP-based approach is developed to solve the proposed model. Finally, case studies are performed on the modified IEEE 33-node system to verify the effectiveness and efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

In this paper, a grid-tie small-scale wind generation system is proposed with innovations in both of the topology and the controller. A novel high step-up zero-current turning-on soft-switching rectifier and a storage branch are employed to improve the low-wind-speed (LWS) and high-wind-speed (HWS) performances. The optimized LWS operation is guaranteed by the rectifier, the battery pack, and film capacitors. The enhanced HWS performance is fulfilled by parallel operation of the inverter and the battery charge converter. Furthermore, the control strategy aiming at improving overall system efficiency and extending battery lifespan and exploitable wind speed range is adopted. A state-of-charge (SOC) control method is used and ensures SOC is most frequently within a range of 20–80%. The proposed method not only slows down the battery capacity fading by SOC scope limitation and by charge/discharge current restriction, but also provides safety capacity margin in case of extreme HWS condition. Also, a simple but reliable dead-zone controller is applied on the battery charge/discharge converter to control the dc-link voltage. Finally, the theoretical analysis and the control method are verified by simulations, experiments, and are tested in the real wind field. [ABSTRACT FROM AUTHOR]

Power system electro-magnetic transient programs (EMTP) have been popular among researchers and practitioners due to their detailed component modeling and high simulation accuracy for complex system operations. Despite broad applications in simulations with wide range of timescales, the small discretization step of these programs makes their use very time-consuming for system studies with long time span. Facing the increasingly complex power system transient characteristics and simulation demands, a multiscale algorithm that integrates the simulations of the electromagnetic and slower electromechanical transients is desirable. The multiscale simulation algorithm preserves the high fidelity of the EMTP and attains higher efficiency for the overall transient simulation. In this paper, we achieve this goal by exploiting the unique properties of the matrix exponential function. The proposed algorithm is capable of utilizing large step sizes to speed up the simulation of slow dynamics, whereas the fast transients are accurately reconstructed through efficient dense output mechanism, which is built upon the matrix exponential function computation. Numerical studies including a large-scale wind farm simulation are conducted to demonstrate the effectiveness of the proposed multiscale algorithm. [ABSTRACT FROM AUTHOR]

Soft open points (SOPs) are power electronic devices installed to replace normally open points in active electrical distribution systems. SOPs can provide active/reactive power flow control and voltage regulation under normal operating conditions as well as fast fault isolation and supply restoration under abnormal conditions. The application of SOPs can improve the controllability of distribution systems, thus further enhances the economy, flexibility and reliability of the grid. In this paper, considering the long-term operation characteristics of distributed generation, a mixed integer non-linear optimization problem is formulated to optimally determine the siting and sizing of SOPs based on the typical operation scenarios generated by Wasserstein distance. It is then transformed to and solved as a mixed integer second-order programming model. Finally, case studies on the IEEE 33-node system and Taiwan Power Company distribution system are used to verify the effectiveness and efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

A novel two-level scheduling method was proposed in this paper, which helps an aggregator optimally schedule its flexible thermostatically controlled loads with renewable energy to arbitrage in the intraday electricity market. The proposed method maximizes the economic benefits of all the prosumers in the aggregation, and naturally helps balance intra-hour differences between supply and demand of the bulk power systems because the prices of the intraday electricity market reflects the need of the bulk power systems. In the proposed two-level scheduling, the upper level is a model predictive control optimization, of which the objective function is to minimize the sum of energy and capacity cost of imbalances and the constraints are thermal constraints based on a proposed energy-balanced model, while the lower level adopts the typical temperature priority list (TPL) control. Simulation results verified the validity of the proposed method and evaluated the effects of important influencing factors. In the base case, 41.64% imbalance cost was saved compared to the reference TPL-based control. Moreover, three further conclusions were drawn: (a) the proposed method mainly saves the imbalance cost by reducing imbalance peak, thus being suitable for places with high capacity price for imbalances; (b) parameter heterogeneity affects the performance of the proposed method, and average value method performs well only with low heterogeneity; (c) the performance of the proposed method worsens with the increase of forecast uncertainty, but keeps better than that of typical TPL-based control unless the forecast uncertainty gets very strong. [ABSTRACT FROM AUTHOR]

A large body of evidence suggests that there were extensive coastal mountains along the East Asian margin during the Late Cretaceous. However, current knowledge of the paleo-mountains — the period, range, and elevation — is limited. Therefore, direct paleoaltimetry is needed to validate and evaluate the paleo-mountains in East Asia. Our study area is Jiaolai Basin, which is located at the East Asian continental margin. We estimate the paleoelevation of Jiaolai Basin during the Late Cretaceous using carbonate clumped isotope paleothermometry. After correcting for seasonal preference, latitudinal difference, and secular climate change, we conclude that the paleoelevation of Jiaolai Basin was almost certainly ≥2.0 km at ∼80 Ma. Combined with the evidence from stratigraphy, paleogeography, and paleoclimatology, our results suggest that the existence of coastal mountains along East Asia during the Late Cretaceous is likely and the model of Okhotomorsk–East Asia collision is preferred. [ABSTRACT FROM AUTHOR]

Several flow zones exist in an ironmaking blast furnace, including the plug flow zone at the upper part, a stagnant zone in the central bottom and a funnel flow zone near the outlet. The prediction of the stagnant zone has remained a difficulty for years, and various approaches have been attempted in the past. In this article, a new approach based on novel potential flow model was employed to predict the profile of the stagnant zone and the plug flow and funnel flow zones. The results were verified by the experimental observations in literature. The effect of the material flow resistance in the model on the stagnant and flowing zones was investigated, and the results were also compared with the traditional potential flow model. It is demonstrated that the novel potential flow model has the advantage in predicting the stagnant and flowing zones simultaneously without a need to implement extra complicated correlations. [Display omitted] • An approach to numerically predict deadman in blast furnace is proposed. • Deadman changes with ratio of potential flow and piping flow resistances. • Predicted results accord fairly well with reality. • Material resistance surely exists within deadman in blast furnace. [ABSTRACT FROM AUTHOR]

This paper proposes a robust scheduling strategy to manage a building energy system with solar power generation system, multi-chiller system and ice thermal energy storage under prediction uncertainty. The strategy employs a two-stage adjustable robust formulation to minimize the system operation cost, wherein a parameter is introduced to adjust the level of conservatism of the robust solution against the modeled uncertainty. Then a column and constraint generation algorithm with modified initialization strategy is adopted to solve this optimization model along with mixed-integer linear programming. Further, we evaluate the performance of the proposed strategy by hourly simulating the system operation of a practical project with Monte Carlo simulation. Numerical results show that the robust scheduling with a proper parameter can be superior to the deterministic strategy in all the studied cases. Additionally, the proposed strategy has similar results with the model-based predictive control strategy while the former only needs to be implemented once. Even in the highest load case, the relative deviation between the two strategies is less than 2%. [ABSTRACT FROM AUTHOR]

An energy management system for stand-alone microgrid composed of diesel generators, wind turbine generator, biomass generator and an ESS (energy storage system) is proposed in this paper. Different operation objectives are achieved by a hierarchical control structure with different time scales. Firstly, the optimal schedules of the diesel generators, wind turbine generator, biomass generator and ESS are determined fifteen minutes ahead according to the super short-term forecast of load and wind speed in the optimal scheduling layer. Comprehensive analysis which takes the uncertainty of load and wind speed into account is conducted in this layer to minimize the operation cost of the system and ensure a desirable range of the state of charge of the ESS. Secondly, the operation points of each unit are regulated dynamically to guarantee real-time power balance and safety range of diesel generation in the real-time control layer, based on which the response capability when suffering significant forecast deviation and other emergency issues, e.g. sudden load-up can be improved. Finally, the effectiveness of the proposed energy management strategy is verified on an RT_Lab based real-time simulation platform, and the economic performances with different types of ESS are analyzed as well. [ABSTRACT FROM AUTHOR]

In deep time, climates are mainly classified by climatically sensitive deposits, paleontological evidences, and modeling. However, they only have limited applicability in deep time studies. Here, we propose a new paleoclimate classification based on the widely used Köppen climate classification. The proposed new classification is simple and quantitative, but bridges the gap between modern and deep time climate studies. The new classification is closely related to but differs from that of Köppen by changing some limits. A world map using the new classification shows the same patterns as the world map of the Köppen climate classification. Using the new classification, we are able to solve a long-standing problem about the climates of East Asia during the Eocene. We found that East Asia shared the same climate type (Ca: Subtropical) at all studied locations, supporting the hypothesis of monsoon or monsoon-like climate that prevailed there during the Eocene. [ABSTRACT FROM AUTHOR]

In this paper, a robust approach is developed to tackle the uncertainty of PV power output for load scheduling of smart homes integrated with household PV system. Specifically, a robust formulation is proposed and further transformed to an equivalent quadratic programming problem. Day-ahead load schedules with different robustness can be generated by solving the proposed robust formulation with different predefined parameters. The validity and advantage of the proposed approach has been verified by simulation results. Also, the effects of feed-in tariff and PV output have been evaluated. [ABSTRACT FROM AUTHOR]

The Tertiary lacustrine Niubao Formation is well exposed in the middle-western part of the Lunpola Basin, central Tibetan Plateau, where crude oil was once discovered during drilling campaigns. Sedimentological, organic petrographic and geochemical work was performed on the upper and middle members of this formation in order to investigate its hydrocarbon source rock potential. Sedimentological analyses indicate that both members were deposited in relatively deep lake conditions away from the influence of big stream system, with the upper Niubao Formation (UNF) having higher sand content. The two members contain abundant high-quality Type I kerogen derived mainly from plankton, algae, and bacteria. Compared with samples of the middle Niubao Formation (MNF), UNF samples also contain more Type II and Type III kerogens of terrestrial origin. Biomarkers of source rock extracts suggest that a long-standing anoxic, stratified, and saline ancient lake occupid the basin during deposition of the two members, which was conducive to the preservation of organic matter. However, higher gammacerane content and the presence of β-carotane in MNF samples imply a more saline lake condition. Rock-Eval T max and biomarker parameters reveal marginal maturity and immaturity for samples from MNF and UNF, respectively. Therefore, MNF has better source rocks of higher maturity might be the main hydrocarbon generating member of the basin; similar diagnostic biomarkers and biomarker parameters reported in the crude oil also imply its affiliation with the source rocks of MNF. [ABSTRACT FROM AUTHOR]

The Namling–Oiyug basin is the only Cenozoic lake basin that has hydrocarbon potential in southern Tibet, China. Coal was once exploited in the basin from the early Miocene Mangxiang Formation, which also hosts oil-prone source rock layers. Herein, a combined investigation of sedimentological features and organic geochemistry is performed on a measured outcrop section of the Mangxiang Formation to study the lake-basin types as well as the depositional history of aquatic and terrestrial organic matter (OM). There are two periods in the lake basin evolution history: the balanced-fill and overfilled stages. In the balanced-fill basin stage, oil-prone laminated shale was deposited in a relatively deep lake environment, with total organic carbon (TOC) contents around 5 wt.%, and HI values up to 316 mg HC/g TOC, indicating hydrogen-poor Type II kerogen with transition to Type III kerogen. Comparison between maceral composition and geochemical properties suggests that the relative low HI values are results of thermal maturity. The high value of the gammacerane index indicates water stratification of the lake. In this stage, water and sediment input approximately equaled potential accommodation, the lake was relatively stable and hosted large amounts of lacustrine algae, and accumulated OM with low terrestrial input in an anoxic environment. After the onset of the thrusting, the potential accommodation was decreased, large volumes of clastic sediments also drained into the lake from the surrounding area, resulting in an overfilled lake basin. During this stage, peat was deposited in freshwater environment, with > 30 wt.% TOC, low HI, and Type III OM. The high Pr/Ph (> 3) implies oxic conditions. [ABSTRACT FROM AUTHOR]

This paper proposes an accurate dense output formula for exponential integrators. The computation of matrix exponential function is a vital step in implementing exponential integrators. By scrutinizing the computational process of matrix exponentials using the scaling and squaring method, valuable intermediate results in this process are identified and then used to establish a dense output formula. Efficient computation of dense outputs by the proposed formula enables time integration methods to set their simulation step sizes more flexibly. The efficacy of the proposed formula is verified through numerical examples from the power engineering field. [ABSTRACT FROM AUTHOR]

Long-standing problems in the geological evolution of the Tibetan–Himalayan orogen include where the India–Asia convergence was accommodated and how the plateau grew. To clarify these problems, we review the deformations and their role in the plateau's growth. Our results show that ~ 1630 km of shortening occurred across the Tibetan–Himalayan orogen since ~ 55 Ma, with more than ~ 1400 km accommodated by large-scale thrust belts. These thrust belts display an outward expansion from central Tibet and couple with the surficial uplift. The development of the Tibetan plateau involved three significant steps: Primitive plateau (~ 90–55 Ma), Proto-plateau (~ 55–40 Ma), and Neoteric plateau (~ 40–0 Ma). Several processes have collaborated to produce the Proto-plateau, including the pre-existing Primitive plateau, the India–Asia collision, and subductions of Greater India and Songpan–Ganzi beneath the Lhasa–Qiangtang terrane. Since ~ 40 Ma, the Proto-plateau, which was dominated by a topographic gradient, lower crustal flow and continuous India–Asia convergence, experienced three periods of rapid outward growth (~ 40–23, ~ 23–10, and ~ 10–0 Ma) in general. The N–S trending rifts were caused by the eastward growth of the plateau dominated by thrusting and crust flow in central Tibet, while they were the results of intense N–S shortening in Himalaya. [ABSTRACT FROM AUTHOR]

With the increasing penetration of distributed generation, distribution networks are evolving from passive to active. New transient simulation methods are required to study the detailed dynamic characteristics of large‐scale active distribution networks. A model order reduction method based on Krylov subspace theory is introduced in this study to reduce the overall model scale of active distribution networks for transient simulations. A modified state‐space model of linear distribution networks is developed to replace the conventional models for improvement in model reduction efficiency, while guaranteeing the passivity and stability of the reduced models. The proposed model order reduction method is validated with the IEEE 123‐node test network. The results prove that the proposed method is effective for different applications to improve the simulation efficiency of large‐scale active distribution networks. [ABSTRACT FROM AUTHOR]

The history of volcanic activity of the Gangdese arc in southern Tibet during the Cretaceous remains poorly known due to the intense erosion of the arc. Here we present zircon U–Pb ages, trace element and Hf isotopic data of tuffs and volcanic conglomerates from the Chongdoi and the Ngamring Formation in the Xigaze forearc basin. Three tuff samples from the Chongdoi Formation yield zircon U–Pb ages around 112 Ma. Such ages could be taken as their depositional ages, indicating that detrital clasts of the Chongdoi Formation were deposited at that time. One andesitic conglomerate sample from the Ngamring Formation was dated at ca. 105 Ma, the other rhyolitic conglomerate sample and one tuff sample were dated to be ca. 95 Ma and 91 Ma, respectively, suggesting that this formation was formed during the late Albian–late Turonian. All zircons illustrate I-type granitoid characteristics and possess low Ti-in-zircon temperatures (< 800 °C). Zircon ε Hf (t) values of tuffs from the Chongdoi Formation define two groups: (1) the first group of 117–110 Ma displays large positive ε Hf (t) values (+ 12.1 to + 17.1), larger than those of the tuff from the Ngamring Formation (+ 6.0 to + 10.2); (2) the second group of 119–111 Ma yields negative to small positive ε Hf (t) values (− 4.5 to + 1.1). All above observations indicate that their host rocks were derived from the juvenile materials with significant input of fluids. Combined with extant data, the first group and the tuff, volcanic conglomerates from the Ngamring Formation are mostly likely derived from the eroded Cretaceous volcanic rocks in the Gangdese arc, while the second group is likely sourced from the late Early Cretaceous volcanic rocks in the central Lhasa terrane. Our data confirm the presence of Cretaceous volcanism in the Gangdese arc, suggesting that the Neo-Tethyan Ocean lithosphere was most likely subducted northerly in a normal angle rather than in a manner of low-angle subduction. [ABSTRACT FROM AUTHOR]

Abstract: The surface uplift history of the Tibetan Plateau (TP) offers a key testing ground for evaluating models of collisional tectonics and holds important implications for processes ranging from global cooling to the onset of the Asian monsoon. Various models have been proposed to reveal the surface uplift history of the TP, but controversies remain. We evaluate these models using data from sedimentology and stratigraphy, structural geology, magmatism, exhumation, and paleoaltimetry studies. Structural analyses indicate that thrust belts, which spread from the central TP outward toward its surrounding margins, accommodated most of the India–Asia convergence, and facilitated crustal shortening and thickening in the central TP. Eocene adakitic rocks located in the Qiangtang and the Lhasa blocks likely were generated by partial melting of an eclogitic source. Paleogene (50–30Ma) potassic rocks only occur in the Qiangtang block, whereas Late Oligocene–Late Miocene (26–8Ma) potassic rocks occur both in the Qiangtang and Lhasa blocks. Low-temperature thermochronologic ages in the central TP are older than 40–35Ma, whereas those in the margins are younger than 20Ma (mostly Late Miocene, and Pliocene/Pleistocene in age). Independent paleoaltimetry estimates suggest that the Lhasa and Qiangtang terranes attained their current elevations during the Eocene, most likely due to the initial collision between India and Lhasa, whereas the Hoh Xil basin area to the north and Himalayas to the south were still low, even below sea level in the latter case. We argue for an inside-out growth pattern for the Tibetan Plateau. The TP grew southward and northward from a nucleus of high topography and is likely to continue expanding along the Mazar Tagh fault to the northwest, the Kuantai Shan-Hei Shan-Longshou Shan to the northeast, the Longquan Shan to the east and the Shillong plateau to the south if the northward force of India would not diminished. [Copyright &y& Elsevier]

Abstract: Cretaceous climate data of the long-lived Cretaceous Songliao Basin (SB) in eastern Asia is correlated and compared with the Western Interior Seaway (WIS) on the northern American plate, in order to understand better the dynamics of the Earth's past ‘greenhouse’ climates. Nearly continuous Late Cretaceous terrestrial deposition in the Songliao Basin is represented by two cores totaling 2431m in length. The Turonian–Maastrichtian age of the section is based on integrated stratigraphy, and is comparable in age with Upper Cretaceous strata in the WIS. Being consistent with global trends, the dynamic Late Cretaceous climates of both the SB and WIS gradually cooled from the warmest Albian–Cenomanian time to the end of the Maastrichtian with several intervening warm periods as did the global climate. However regional differences existed, the Songliao Basin climate was humid to semi-humid, warm temperate–subtropical and the Western Interior Seaway was in the humid, warm temperate zone and experienced only moderate climatic changes. The shifts of oxygen isotope data in the Songliao Basin were frequent and abrupt, whereas WIS records more gradual change affected mainly by fresh-water runoff mixing with southern Tethyan and northern Arctic waters. Sedimentary cycles of eccentricity, obliquity and precession bands are recorded in both the SB and WIS basins. The sedimentary cycles in the WIS and SB are interpreted to be related to variations of the wet/dry runoff cycles, which indicate that orbital forcing played an important role in global climate change in Late Cretaceous. The most favorable condition for organic carbon burial in both the SB and WIS basin was bottom water anoxia regardless of the cause of the anoxia. But the organic carbon burial rate was usually much higher in the Songliao Lake than in the WI epeiric sea suggesting that giant lakes may serve as important sinks of atmospheric CO2. In both basins organic-rich deposits formed during a rise in water level and incursion of saline waters. The integration of paleoclimate data from Cretaceous marine deposits and terrestrial sedimentary record will promote our understanding of the Cretaceous ‘greenhouse’ climate change and may provide insights for a future greenhouse world. [Copyright &y& Elsevier]

Abstract: In order to define the provenance change across the nonconformable boundary between the second and the third members of the Upper Cretaceous Nenjiang Formation (Campanian) in the north-central area of the Songliao Basin, two sandstone samples above (sample a-1 from the fourth member of the Nenjiang) and below (sample z-1 from the first member of the Yaojia Formation) the nonconformity were collected from core holes. U–Pb dating was performed on detrital zircons separated from the three sandstone samples. Detrital zircons from sample a-1 have dominant age populations of 100–110Ma, 190–220Ma, and ~1800Ma, and sample z-1 has dominant ages of 130–150Ma and ~350Ma. This paper demonstrates that the provenance of the fourth member of the Nenjiang Formation is significantly different from the first member of the Coniacian Yaojia Formation. The provenance above the nonconformity became much more complex and the eastern source increased significantly, while the western source sharply declined. The main source areas of the fourth member of the Nenjiang Formation are mainly the Zhangguangcai Range, the eastern Lesser Xiang'an Range and the southeast of Songliao Basin. The dominant provenance of the first member of the Yaojia Formation is the northern, the central and the southern Great Xing'an Range. According to the depositional ages and combining the latest seismic stratigraphic profiles in the Songliao Basin, the tectonic inversion of the eastern Songliao Basin began between 73Ma and 87Ma, which differs from the previous age of 73Ma. [Copyright &y& Elsevier]

Abstract: Clay mineralogy of a 60m thick section of the middle Mingshui Formation (upper Campanian to lower Maastrichtian) from the SKIn borehole (Songliao Basin in NE China) has been studied to assess the palaeoclimate and provenance. The sedimentary succession is composed of shore to shallow lacustrine mudstones and siltstones in the lower part, and meandering fluvial sandstone–mudstone sequences in the upper part. The clay mineral assemblage is characterized by the predominance of smectitic minerals, with some exceptions of illite-rich layers, and trace amounts of kaolinite and chlorite. The high smectite content (>90% on average) in lacustrine sediments could source from erosion of smetitic soils and volcanic materials in source areas. The Lesser Xing'an–Zhangguangcai Range was the potential provenance area for the sediments, with volcanic activity occurring at ~70Ma, when the temperate semi-humid palaeoclimate was favorable for the clay formation. Smectite presented in meandering fluvial sandstones is of early diagenetic origin, formed by hydrolysis and alteration of primary minerals after deposition. Illite in overbank deposits is interpreted as a result of erosion of granitic rocks and sorting in sedimentation processes. The clay mineralogy of the studied strata contains information on palaeoclimate and provenance, although early diagenetic processes may have influenced the mineralogical composition in some intervals of sandstones. [Copyright &y& Elsevier]

Abstract: The Continental Scientific Drilling Project at the Cretaceous-age Songliao Basin is a drilling initiative under the framework of the International Continental Scientific Drilling Program, to recover a nearly complete Cretaceous terrestrial sedimentary record in the Songliao Basin, northeastern China. The recovered cores will provide unique opportunities for the geosciences community to advance the understanding of climate change in the Cretaceous greenhouse world, and provide a documentation of geological events relevant to the carbon cycle during this time period. This drilling project will address significant geological questions, such as the identification of important stratigraphic boundaries and the marine-terrestrial correlations of stratigraphy, the reasons for the biotic response to the terrestrial environmental changes, the terrestrial response to the Cretaceous oceanic anoxic events, the formation of terrestrial petroleum source rocks, and the mechanisms for the Cretaceous magnetic Normal Superchron (CNS). In the first stage of this drilling project, the SKI drilling, rock cores of 2485.89m in total length were recovered and the recovery ratio reached 96.46%. A series of drilling and coring technologies including regular, confined, directional, and sealed coring, were utilized to ensure a higher recovery ratio for the core, and will be described at the end of this paper. Well loggings were conducted right after coring. Core handling and storage were arranged in such a way that the scientific research was conducted on half of each core, whereas the other half of each core was preserved for long-term storage. The upcoming second stage, the SKII drilling, will combine with data from the existing SKI to provide complete high-resolution climate records of the terrestrial environment for the whole Cretaceous time period. [Copyright &y& Elsevier]

Abstract: As a paradigm of greenhouse climate in Earth's history, the Cretaceous provides significant rock records of global climate changes under conditions of greenhouse climate. The Songliao Basin, among the longest duration (85–90m.y.) of continental sedimentary basins, provides an excellent opportunity to recover a nearly complete Cretaceous terrestrial sedimentary record. Extensive lake deposits, ten-kilometers deep and covering an area of 260,000km2 of the Songliao Basin, provide unique, detailed records that can be tied to the global stratigraphic time scale, thereby improving our understanding of the continental paleoclimate and ecological system. The two coreholes at SKIs and SKIn sites were drilled into this basin and completed with a total length of 2485.89m of recovered core that spanned the complete middle-to-Upper Cretaceous strata in the basin. The unique geological setting of long-term continuous subsidence within the largest Cretaceous landmass in the world — makes the Cretaceous Songliao Basin of northeastern China an ideal place to study Cretaceous climate change on the continent. This paper reviews the literature on the paleogeography and paleoclimate of the northern East Asia and the Songliao Basin during the Cretaceous. Based on the climatologically sensitive deposits, oxygen isotope studies, and paleontology, the climate during the Cretaceous in the Songliao Basin was temperate and humid with relatively abundant rainfall. During the period, significant changes – four cooling, three warming, and three semiarid events – are generally consistent with the oxygen isotope data from East Asia, and the four cooling events, in Berriasian–Valanginian, Aptian–Albian, early Santonian, and Campanian–Maastrichtian, may be related to potential glaciations in Cretaceous. [Copyright &y& Elsevier]

For a droop-controlled micro-grid, it is essential to design the droop coefficients for the inverter controllers in a rational way since they have great influences on the operation characteristics of the system. In this paper, a novel approach based on matrix perturbation theory is proposed for the coordinated optimization of the droop coefficients in inverter controllers. Rigorous perturbation analysis is applied to the droop coefficients to identify their influence on the system state matrix. Furthermore, the increments of the eigensolutions are obtained based on the matrix perturbation theory and are then utilized in the iterative parameter-optimization process. An eigenvalue-based objective function is proposed, aimed at ensuring the stability of the system, enhancing the damping characteristics, and maintaining the stability margin for a wide range of operating conditions. Finally, the effectiveness and robustness of the proposed approach are tested via a low-voltage micro-grid prototype. [ABSTRACT FROM PUBLISHER]

Abstract: The Cretaceous Xigaze ophiolite is best exposed at the central Yarlung Zangbo Suture Zone (YZSZ, Tibet) which also includes the Gangdese arc and the Xigaze forearc basin. This study reports new geochronological and geochemical data for this ophiolite to revisit its geodynamic and petrogenetic evolution. The Xigaze peridotites have low CaO and Al2O3 contents and U-shaped Rare Earth Element (REE) patterns, suggesting that they are residues after moderate to high degrees of partial melting and were modified by infiltration of Light Rare Earth Element (LREE)-enriched boninitic melts. The Xigaze crustal rocks belong to two groups: Mid-Ocean Ridge Basalt (MORB)-like rocks and boninitic rocks showing a uniform LREE depletion and flat to LREE enrichment on chondrite-normalized patterns, respectively. Geochemically, both groups show the influence of subducting oceanic slab-derived fluids. LA-ICPMS zircon U–Pb and Lu–Hf analyses from dolerite and quartz diorite dikes, which intruded into the mantle peridotite, and dolerite sheeted sills show that they were generated between 127 and 124Ma. The zircons possess positive εHf(t) values ranging from +7.5 to +17.3. Taking into account the geological and geochronological characteristics of the central-western YZSZ, we propose that ophiolites in this region formed in a forearc spreading setting through rapid slab rollback during subduction initiation between 130 and 120Ma. Following this stage of spreading, the forearc was stabilized and the zone of melting migrated beneath the Gangdese arc producing the voluminous Late Cretaceous granitoids displaying depleted mantle-type Hf isotopic compositions. Our model provides a new explanation for the generation and evolution of forearc-type ophiolites. [Copyright &y& Elsevier]

Abstract: To understand the magmatic and tectonic events in the Eastern Kunlun Range, we conducted systematic zircon U–Pb geochronology, and paired zircon (ZHe) and apatite (AHe) (U–Th)/He themchronology investigations in the central and eastern segments of this range. Zircon U–Pb ages show two-stage magmatic events of Late Silurian and latest Permian–Early Jurassic. ZHe and AHe ages and multi-system thermochronometers reveal multi-stage rapid cooling events. From a combination of these data with previously published geochronological and thermochronological ages, and regional geological setting, we confirm several important Phanerozoic tectono-magmatic events in this region. Whereas the Silurian granites might be related to a small paleo-ocean subduction and subsequent collision, the latest Permian–Early Triassic granitoids were produced by northward subduction of the Songpan–Ganzi Paleo-Tethyan ocean. The Late Triassic–earliest Jurassic granitoids and Late Triassic–Early Jurassic exhumation are interpreted as response to the collision between Kunlun–Qaidam and Qiangtang. Samples close to the Kunlun Fault show rapid Late Oligocene–Early Miocene exhumation (1.3–1.6km/Ma), whereas those from the northern part of central segment display extremely low exhumation rates (0.02–0.05km/Ma). This heterogeneous denudation during 30–20Ma between northern and southern part of the central segment requires that crustal thickening was completed by lower-crustal underthrusting with little exhumation or crustal thickening in pre-Cenozoic times. The activity of the Kunlun Fault and associated normal faulting component were probably responsible for this stage of rapid exhumation in the southern part. The complex tectono-magmatic evolution of the Eastern Kunlun Range is controlled by pre-Cenozoic paleo-ocean subductions and subsequent continent collisions and Paleogene India–Asia collision. [Copyright &y& Elsevier]

Abstract: The interparticle distance of CdSe(ZnS) quantum dots was accurately controlled by polymerization at the air–water interface which provided an increased homogeneity of the Langmuir–Blodgett film leading to a surface smoothness comparable to mica. The choice of a silane derivative is based on the fact that silicon is semiconductor, and the compound CdSe being the core of the quantum dot is also semiconductor. The combination of the two semiconductors could bring some unusual conduction properties as a polymeric silanized network. But first, it is most important to characterize the smoothness of the surface, which might be correlated to the formation of “trap” states, i.e. the photo-excited electron can fall, or the photo-excited hole can “float”. One will focus our research strategy, as a pilot study, to characterize the surface of the new polymeric material. [Copyright &y& Elsevier]