There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

An introduction to heat transfer

A critical synthesis of thermophysical characteristics of nanofluids

In this work, we design and construct a novel 2D/2D g-C 3 N 4 nanosheet@ZnIn 2 S 4 nanoleaf via a simple one-step surfactant-assisted solvothermal method for photocatalytic H 2 generation. Its unusual 2D/2D heterojunction structure provides far more contact areas and much faster charge transport rate than the 2D/0D heterojunction structure of g-C 3 N 4 nanosheet@ZnIn 2 S 4 microsphere. More importantly, this unique 2D/2D heterojunction leads the g-C 3 N 4 nanosheet@ZnIn 2 S 4 nanoleaf composite to generate numerous intimate high-speed charge transfer nanochannels in the interfacial junctions, and which could considerably enhance the photogenerated charge separation and migration efficiency, thus yielding a remarkable visible-light-driven H 2 evolution rate without the additive Pt cocatalyst (HER = 2.78 mmol h −1  g −1 ), nearly 69.5, 15.4, 8.2 and 1.9 times higher than that of pure g-C 3 N 4 nanosheet, pure ZnIn 2 S 4 microsphere, 2D/0D g-C 3 N 4 nanosheet@ZnIn 2 S 4 microsphere and pure ZnIn 2 S 4 nanoleaf, respectively. Additionally, the 2D/2D g-C 3 N 4 nanosheet@ZnIn 2 S 4 nanoleaf exhibits an outstanding stability and recyclability, manifesting a promising potential application in sustainable energy conversion. This work would provide a platform for the design and synthesis of binary heterojunction composite system with highly-efficient charge separation and transfer.

Preparation of 2D/2D g-C3N4 nanosheet@ZnIn2S4 nanoleaf heterojunctions with well-designed high-speed charge transfer nanochannels towards high-efficiency photocatalytic hydrogen evolution

Preparation of highly dispersed nanofluid and CFD study of its utilization in a concentrating PV/T system

Grafing the structures in nature onto g-C 3 N 4 is an interesting and fascinating protocol to highly optimize its performances. Herein, a novel opened-up fish-scale structured g-C 3 N 4 nanosheet has been synthesized via a simple one-step solvothermal method for photocatalytic hydrogen evolution. The unique fish-scale structure endows g-C 3 N 4 with unusual spatial electron transfer property, which means that the photogenerated electrons selectively migrate along the flat direction to the edges of fish-scale flakes. This property well reveals the transfer path of photogenerated charges and the origin of high charge separation efficiency in photocatalytic reaction, thus yielding a remarkable catalytic activity (a hydrogen-evolution rate of 1316.35 μ mol h −1  g −1 ), nearly 20 and 2.93 times higher than that of bulk g-C 3 N 4 and exfoliated g-C 3 N 4 nanosheet. Besides, the fish-scale structured g-C 3 N 4 also owns a superior durability and stability, indicating an outstanding potential application in solar fuel production. The research results would provide a platform for the design and construction of high-performance photocatalysts with highly-efficient charge separation.

Fish-scale structured g-C3N4 nanosheet with unusual spatial electron transfer property for high-efficiency photocatalytic hydrogen evolution

Minimizing the charge transfer barrier to realize fast spatial separation of photoexcited electron–hole pairs is of crucial importance for strongly enhancing the photocatalytic H2 generation activity of photocatalysts. Herein, we propose an electron transfer strategy by reasonable design and fabrication of high-density NiSx quantum dots (QDs) as a highly efficient cocatalyst on the surface of Cd0.8Zn0.2S/rGO nanosheet composites. Under visible-light irradiation, the formation of a two-dimensional (2D) Cd0.8Zn0.2S/rGO nanohybrid system with 2 wt % NiSx loading gave a prominent apparent quantum efficiency (QE) of 20.88% (435 nm) and H2 evolution rate of 7.84 mmol g–1 h–1, which is 1.4 times higher than that of Pt/Cd0.8Zn0.2S/rGO. It is believe that the introduced rGO nanosheets and NiSx QDs obviously improved the interfacial conductivity and altered the spatial distribution of electrons in this nanoarchitecture. Thus, the synergistic effects of interfacial junctions result in a regulated electron transporta...

NiSx Quantum Dots Accelerate Electron Transfer in Cd0.8Zn0.2S Photocatalytic System via an rGO Nanosheet “Bridge” toward Visible-Light-Driven Hydrogen Evolution

Two-dimensional (2D) layered Perovskite-type La2Ti2O7 has emerged as the most exciting photovoltaic material in the next generation clean energy technologies. This study presents a facile strategy to improve the photocatalytic performance of La2Ti2O7 by energy level engineering via phosphor doping and well-controlled layer-by-layer assembly of stacked P-La2Ti2O7/Bi2WO6 heterojunctions. The non-metal P-type element doping optimizes the electronic configuration and modulates valence states of ions, resulting in enhanced activities of perovskite photocatalyst. Additionally, the integration of 2D Bi2WO6 generates abundant intimate heterogeneous interfacial contacts, which is beneficial for expediting charge separation and effectively suppressing electron–hole pair recombination across the heterojunction, eventually contributing to enhanced photocatalytic efficiency of the system. As a result of synergies, the 2D/2D layered P-La2Ti2O7/Bi2WO6 contact heterojunctions exhibited excellent visible-light-driven photocatalytic activities and sustained cycling performance. An RhB degradation efficiency of up to 99.02% was achieved under visible-light irradiation within 80 min.

Jinjia Wei

Papers

Preparation of 2D/2D g-C3N4 nanosheet@ZnIn2S4 nanoleaf heterojunctions with well-designed high-speed charge transfer nanochannels towards high-efficiency photocatalytic hydrogen evolution

Preparation of highly dispersed nanofluid and CFD study of its utilization in a concentrating PV/T system

Fish-scale structured g-C3N4 nanosheet with unusual spatial electron transfer property for high-efficiency photocatalytic hydrogen evolution

NiSx Quantum Dots Accelerate Electron Transfer in Cd0.8Zn0.2S Photocatalytic System via an rGO Nanosheet “Bridge” toward Visible-Light-Driven Hydrogen Evolution

Highly efficient charge transfer at 2D/2D layered P-La2Ti2O7/Bi2WO6 contact heterojunctions for upgraded visible-light-driven photocatalysis