Context
Landscape composition and configuration determine the generation and exchange of water flows among different landscape patches and may affect catchment hydrological flows and variations. ...However, the poor understanding on the effects of landscape patterns on hydrological processes limits the implementation of landscape planning and management practices for regulating catchment water resources at the practical level.
Objectives
The aims are to determine the relationship between the landscape pattern and hydrological flows and variations, and to compare the contributions of landscape composition and configuration to the hydrological flows and variations.
Methods
Landscape patterns were quantified and hydrological flows and variations were observed in a Chinese subtropical catchment with ten sub-catchments during 2011–2017. The relationship among landscape composition, configuration, and hydrological flows and variations was analysed by Pearson correlation, and their relative contributions were determined by the variance partitioning analysis.
Results
Landscape composition and configuration were significantly correlated with catchment stream, direct, and base flows and variations, of which high fragmentation degree increased stream and base flows, great shape complexity aggravated the volatility of stream flow, high patch aggregation adversely impacted stream, direct, and base flows, and high patch evenness and lower richness increased stream and base flows. Landscape composition and configuration indices could be employed to effectively predict hydrological flows and variations.
Conclusions
Landscape configuration had greater contribution than landscape composition to subtropical catchment hydrological flows and variations, and optimizing landscape configuration could improve our regulatory capacity and ability of catchment water resources management and utilization in the subtropical catchments at the practical level.
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EMUNI, FZAB, GEOZS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Expansion of the wavelength range for an ultrafast laser is an important ingredient for extending its range of applications. Conventionally, optical parametric amplification (OPA) has been employed ...to expand the laser wavelength to the infrared (IR) region. However, the achievable pulse energy and peak power have been limited to the mJ and the GW level, respectively. A major difficulty in the further energy scaling of OPA results from a lack of suitable large nonlinear crystals. Here, we circumvent this difficulty by employing a dual-chirped optical parametric amplification (DC-OPA) scheme. We successfully generate a multi-TW IR femtosecond laser pulse with an energy of 100 mJ order, which is higher than that reported in previous works. We also obtain excellent energy scaling ability, ultrashort pulses, flexiable wavelength tunability, and high-energy stability, which prove that DC-OPA is a superior method for the energy scaling of IR pulses to the 10 J/PW level.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The Universal Process Yuxi Fu
Logical methods in computer science,
01/2017, Volume:
13, Issue 4
Journal Article
Peer reviewed
Open access
A universal process of a process calculus is one that, given the G\"{o}del index of a process of a certain type, produces a process equivalent to the encoded process. This paper demonstrates how ...universal processes can be formally defined and how a universal process of the value-passing calculus can be constructed. The existence of such a universal process in a process model can be explored to implement higher order communications, security protocols, and programming languages in the process model. A process version of the S-m-n theorem is stated to showcase how to embed the recursion theory in a process calculus.
Fully coherent, soft X-ray attosecond pulses are now available through high-order harmonic generation (HHG); however, the output energy is insufficient for various applications, such as ...attosecond-scale soft X-ray nonlinear experiments, the seeding of soft X-ray free-electron lasers, attosecond-pump-attosecond-probe spectroscopies, and single-shot imaging. In this paper, we combine a newly developed TW class mid-infrared femtosecond laser and a loose focusing geometry for HHG. A soft X-ray harmonic beam up to the water window region is demonstrated, which is more than 100 times intense compared to previous works. We achieve a high conversion efficiency, low beam divergence and a significantly reduced medium gas pressure. As the first application, we demonstrate near edge X-ray absorption fine structure experiments with clear fine absorption spectra near the K- and L-edges observed. The robust energy scaling method on HHG opens the door for demonstrating single-shot absorption spectrum and live-cell imaging with a femtosecond time resolution.While high harmonic x-ray sources are well established sources for ultrafast spectroscopy, the decrease in efficiency towards higher energies limits their application. Here, a loose-focused, TW mid-IR laser is used to generate high harmonic soft x-rays with pulse energies of a few nJ in the water window and easy energy scaling.
This note shows that several statements about fixpoints in order theory are equivalent to Knaster–Tarski Fixpoint Theorem for complete lattices. All proofs have been done in Zermelo–Fraenkel set ...theory without the Axiom of Choice.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This paper presents the optimization of a dual-chirped optical parametric amplification (DC-OPA) scheme for producing an ultrafast intense infrared (IR) pulse. By employing a total energy of 0.77 J ...Ti:sapphire pump laser and type-I BBO crystals, an IR pulse energy at the center wavelength of 1.7 µm exceeded 0.1 J using the optimized DC-OPA. By adjusting the injected seed spectrum and prism pair compressor with a gross throughput of over 70%, the 1.7-µm pulse was compressed to 31 fs, which resulted in a peak power of up to 2.3 TW. Based on the demonstration of the BBO type-I DC-OPA, we propose a novel OPA scheme called the "dual pump DC-OPA" for producing a high-energy IR pulse with a two-cycle duration.
High-energy infrared (IR) femtosecond laser sources are important for applications in ultrafast and strong-field laser science; thus, considerable effort has recently been made to develop such laser ...systems. In this paper, we review our recent work on developing TW-class mid-infrared (MIR) femtosecond laser pulses in the 1-4 <inline-formula><tex-math notation="LaTeX">\mu</tex-math></inline-formula>m region using a dual-chirped optical parametric amplification (DC-OPA) method. By employing a Ti:sapphire laser with sub-joule energy to pump the DC-OPA system, MIR femtosecond pulses with 100-mJ-class energy are demonstrated. Efficient energy scalability and flexible wavelength tunability in DC-OPA are confirmed experimentally. Different features of DC-OPA from those of conventional OPA and narrow-band pumped optical parametric chirped pulse amplification (OPCPA) are observed. By precisely optimizing the chirps of the seed and pump pulses in the DC-OPA system, bandwidth narrowing of amplified pulses can be minimized in an energy-scaling strategy. Moreover, DC-OPA can be universally employed for the energy scaling of near-IR, MIR, and far-IR pulses, regardless of the type of nonlinear crystal, and is helpful for efficiently generating few-cycle carrier-envelope phase stable IR pulses with TW-class peak power.
There is a lot of research on probabilistic transition systems. There are not many studies in probabilistic process models. The lack of investigation into the interactive aspect of probabilistic ...processes is mainly due to the difficulty caused by the discrepancy between probabilistic choices and nondeterministic actions. The paper proposes a uniform approach to probabilistic process models and a bisimulation theory for probabilistic concurrency.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In order to overcome the problem that the traditional linear energy harvesting (EH) model is not practical, this paper presents a practical nonlinear EH model, which considers the sensitivity and ...saturation characteristics of the circuit. Furthermore, for purpose of solving the problem of spectrum requirement and energy consumption of wireless relays, the proposed model in this paper is used for studying the full-duplex (FD) decode-and-forward relay system. The expression of the outage probability of the system is deduced and the outage throughput of the system is calculated. According to different system quality of service (QoS) requirements, this paper further discusses the optimal scheme of non-linear EH based on outage performance and gives the closed expression of the optimal solution to minimize the outage probability of the FD system. And the optimal solution to maximize the outage throughput of the system is obtained based on the golden section method. The simulation results verify the correctness of the theoretical work, and the simulation results also show that the performance of the FD system under the proposed model is quite different from that of the traditional linear model.
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