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1. Contrasting Local and Long-Range Transported Warm Ice-Nucleating Particles During an Atmospheric River in Coastal California, USA

   https://doi.org/10.5194/acp-2018-702  

   Martin, Andrew C.; Cornwell, Gavin; Beall, Charlotte Marie; Cannon, Forest; Reilly, Sean; Schaap, Bas; Lucero, Dolan; Creamean, Jessie; Ralph, F. Martin; Mix, Hari T.; et al (July 2018, Atmospheric Chemistry and Physics Discussions)

   Abstract. Ice nucleating particles (INP) have been found to influence the amount, phase, and efficiency of precipitation from winter storms, including atmospheric rivers. Warm INP, those that initiate freezing at temperatures warmer than −10°C, are thought to be particularly impactful because they can create primary ice in mixed-phase clouds, enhancing precipitation efficiency. The dominant sources of warm INP during atmospheric rivers, the role of meteorology in modulating transport and injection of warm INP into atmospheric river clouds and the impact of warm INP on mixed-phase cloud properties are not well-understood. Time-resolved precipitation samples were collected during an atmospheric river in Northern California, USA during winter 2016. Precipitation was collected at two sites, one coastal and one inland, that are separated by less than 35km. The sites are sufficiently close that airmass sources during this storm were almost identical, but the inland site was exposed to terrestrial sources of warm INP while the coastal site was not. Warm INP were more numerous in precipitation at the inland site by an order of magnitude. Using FLEXPART dispersion modelling and radar-derived cloud vertical structure, we detected influence from terrestrial INP sources at the inland site, but did not find clear evidence of marine warm INP at either site. We episodically detected warm INP from long-range transported sources at both sites. By extending the FLEXPART modelling using a meteorological reanalysis, we demonstrate that long-range transported warm INP are observed only when the upper tropospheric jet provided transport to cloud tops. Using radar-derived hydrometeor classifications, we demonstrate that hydrometeors over the terrestrially-influenced inland site were more likely to be in the ice phase for cloud temperatures between 0°C and −10°C. We thus conclude that terrestrial and long-range transported aerosol were important sources of warm INP during this atmospheric river. Meteorological details such as transport mechanism and cloud structure were important in determining warm INP source strength and injection temperature, and ultimately the impact of warm INP on mixed phase cloud properties. 

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2. ABAQUS Code for the Simulation of Scutoid Interlocked Material Systems

   https://doi.org/10.4231/95MY-8V89  

   Ballance, Tanner; Siegmund, Thomas; Siegmund, Thomas (January 2024, Purdue University Research Repository)

   A series of files for the execution of finite element simulations of topologically interlocked assemblies are provided and can be executed with the finite element code ABAQUS (or similar). In all files the following structure is present: -- For each part of the assembly (frame, indenter, building block), a definition of nodes (*node) and sets of nodes (*nset), elements (*element) and set of elements (*elset) is provided. -- Instances of parts are defined an placed in the assembly at position according to the assembly plan. -- Parts frame and indenter are defined as rigid bodies (*rigid body) . Building blocks as linear elastic (*elastic). -- Boundary conditions and constraints are defined (*boundary) -- Surfaces (*surface), surface behavior (*surface behavior) and contact interactions (*contact) are given. -- A mass scaled explicit solution is used (*dynamic, explicit) -- Computed values are recorded (*node output, *energy output, *element output) ABAQUS inp file for a 6 by 6 assembly of hexagonal scutoids, coefficient of friction 0.4: HexScutoid6x6mu4.inp ABAQUS inp file for a 6 by 6 assembly of hexagonal scutoids, all building blocks fused to a monolithic system: HexScutoid6x6mu4_fused.inp ABAQUS inp file for a 7 by 7 assembly of hexagonal scutoids, coefficient of friction 0.4: HexScutoid6x6mu4.inp ABAQUS inp file for a 6 by 6 assembly of pentagonal scutoids, coefficient of friction 0.4: PentagonScutoid6x6mu4.inp ABAQUS inp file for a 7 by 7 assembly of pentagonal scutoids, coefficient of friction 0.4: PentagonScutoid6x6mu4.inp ABAQUS inp file for a 6 by 6 assembly of tetrahedra, coefficient of friction 0.4: Tetrahedra6x6mu4.inp ABAQUS inp file for a 7 by 7 assembly of tetrahedra, coefficient of friction 0.4: Tetrahedra7x7mu4.inp This work was supported by NSF Award 16622177. 

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3. Surface passivation extends single and biexciton lifetimes of InP quantum dots

   https://doi.org/10.1039/D0SC01039A  

   Yang, Wenxing; Yang, Yawei; Kaledin, Alexey L.; He, Sheng; Jin, Tao; McBride, James R.; Lian, Tianquan (June 2020, Chemical Science)

   Indium phosphide quantum dots (InP QDs) are nontoxic nanomaterials with potential applications in photocatalytic and optoelectronic fields. Post-synthetic treatments of InP QDs are known to be essential for improving their photoluminescence quantum efficiencies (PLQEs) and device performances, but the mechanisms remain poorly understood. Herein, by applying ultrafast transient absorption and photoluminescence spectroscopies, we systematically investigate the dynamics of photogenerated carriers in InP QDs and how they are affected by two common passivation methods: HF treatment and the growth of a heterostructure shell (ZnS in this study). The HF treatment is found to improve the PLQE up to 16–20% by removing an intrinsic fast hole trapping channel ( τ h,non = 3.4 ± 1 ns) in the untreated InP QDs while having little effect on the band-edge electron decay dynamics ( τ e = 26–32 ns). The growth of the ZnS shell, on the other hand, is shown to improve the PLQE up to 35–40% by passivating both electron and hole traps in InP QDs, resulting in both a long-lived band-edge electron ( τ e > 120 ns) and slower hole trapping lifetime ( τ h,non > 45 ns). Furthermore, both the untreated and the HF-treated InP QDs have short biexciton lifetimes ( τ xx ∼ 1.2 ± 0.2 ps). The growth of an ultra-thin ZnS shell (∼0.2 nm), on the other hand, can significantly extend the biexciton lifetime of InP QDs to 20 ± 2 ps, making it a passivation scheme that can improve both the single and multiple exciton lifetimes. Based on these results, we discuss the possible trap-assisted Auger processes in InP QDs, highlighting the particular importance of trap passivation for reducing the Auger recombination loss in InP QDs. 

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4. ABAQUS Code for the Simulation of Topologically Interlocked Material Systems with Skewed Building Blocks

   https://doi.org/10.4231/DPG0-QT07  

   Kim, Dong; Siegmund, Thomas; Siegmund, Thomas (January 2024, Purdue University Research Repository)

   This publication provides files for the finite element simulation of the mechanical behavior of a set of topologically interlocked material (TIM) systems. Files are to be executed with the FE code ABAQUS (TM), Simulia Inc., or need a file translator to be used by other codes if needed. Files are provided for even (i=10) and odd (i=11) numbered square assemblies of (i x i) blocks confined by a rigid frame and subjected to a transverse displacement load at the assembly center. The following files are provided: The simulations are executed as explicit dynamic simulations with a mass-scale approach to extract the quasi-static response. Building blocks are linear elastic and interact with neighbors by contact and friction. The following files are provided BR_tet_i6.inp: File for a TIM system constructed from regular, truncated tetrahedra shaped building blocks. An assembly of 6 x 6 blocks. This is the reference model 1. BR_tet_i8.inp: File for a TIM system constructed from regular, truncated tetrahedra shaped building blocks. An assembly of 8 x 8 blocks. This is the reference model 1. BR_tet_i10.inp: File for a TIM system constructed from regular, truncated tetrahedra shaped building blocks. An assembly of 10 x 10 blocks. This is the reference model 1. BR_tet_i12.inp: File for a TIM system constructed from regular, truncated tetrahedra shaped building blocks. An assembly of 12 x 12 blocks. This is the reference model 1. BR_tet_i5.inp: File for a TIM system constructed from regular, truncated tetrahedra shaped building blocks. An assembly of 5 x 5 blocks. This is the reference model 2. BR_tet_i7.inp: File for a TIM system constructed from regular, truncated tetrahedra shaped building blocks. An assembly of 7 x 7 blocks. This is the reference model 2. BR_tet_i9.inp: File for a TIM system constructed from regular, truncated tetrahedra shaped building blocks. An assembly of 9 x 9 blocks. This is the reference model 2. BR_tet_i11.inp: File for a TIM system constructed from regular, truncated tetrahedra shaped building blocks. An assembly of 11 x 11 blocks. This is the reference model 2. BT1_tet_i6.inp: File for a TIM system constructed from single-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 6 x 6 blocks. BT1_tet_i8.inp: File for a TIM system constructed from single-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 8 x 8 blocks. BT1_tet_i10.inp: File for a TIM system constructed from single-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 10 x 10 blocks. BT1_tet_i12.inp: File for a TIM system constructed from single-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 12 x 12 blocks. BT1_tet_i5.inp: File for a TIM system constructed from single-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 5 x 5 blocks. BT1_tet_i7.inp: File for a TIM system constructed from single-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 7 x 7 blocks. BT1_tet_i9.inp: File for a TIM system constructed from single-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 9 x 9 blocks. BT1_tet_i11.inp: File for a TIM system constructed from single-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 11 x 11 blocks. BT2_tet_i6.inp: File for a TIM system constructed from double-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 6 x 6 blocks. BT2_tet_i8.inp: File for a TIM system constructed from double-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 8 x 8 blocks. BT2_tet_i10.inp: File for a TIM system constructed from double-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 10 x 10 blocks. BT2_tet_i12.inp: File for a TIM system constructed from double-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 12 x 12 blocks. BT2_tet_i5.inp: File for a TIM system constructed from double-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 5 x 5 blocks. BT2_tet_i7.inp: File for a TIM system constructed from double-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 7 x 7 blocks. BT2_tet_i9.inp: File for a TIM system constructed from double-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 9 x 9 blocks. BT2_tet_i11.inp: File for a TIM system constructed from double-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 11 x 11 blocks. BT1_tet_i6_0_34.inp: File for a TIM system constructed from single-skewed, truncated tetrahedra shaped building blocks. Skew angle is 17 degree. An assembly of 6 x 6 blocks. BT1_tet_i8_0_34.inp: File for a TIM system constructed from single-skewed, truncated tetrahedra shaped building blocks. Skew angle is 17 degree. An assembly of 8 x 8 blocks. BT1_tet_i10_0_34.inp: File for a TIM system constructed from single-skewed, truncated tetrahedra shaped building blocks. Skew angle is 17 degree. An assembly of 10 x 10 blocks. BT1_tet_i12_0_34.inp: File for a TIM system constructed from single-skewed, truncated tetrahedra shaped building blocks. Skew angle is 17 degree. An assembly of 12 x 12 blocks. BT1_tet_i5_0_34.inp: File for a TIM system constructed from single-skewed, truncated tetrahedra shaped building blocks. Skew angle is 17 degree. An assembly of 5 x 5 blocks. BT1_tet_i7_0_34.inp: File for a TIM system constructed from single-skewed, truncated tetrahedra shaped building blocks. Skew angle is 17 degree. An assembly of 7 x 7 blocks. BT1_tet_i9_0_34.inp: File for a TIM system constructed from single-skewed, truncated tetrahedra shaped building blocks. Skew angle is 17 degree. An assembly of 9 x 9 blocks. BT1_tet_i11_0_34.inp: File for a TIM system constructed from single-skewed, truncated tetrahedra shaped building blocks. Skew angle is 17 degree. An assembly of 11 x 11 blocks. BT2_tet_i6_0_34.inp: File for a TIM system constructed from double-skewed, truncated tetrahedra shaped building blocks. Skew angle is 17 degree. An assembly of 6 x 6 blocks. BT2_tet_i8_0_34.inp: File for a TIM system constructed from double-skewed, truncated tetrahedra shaped building blocks. Skew angle is 17 degree. An assembly of 8 x 8 blocks. BT2_tet_i10_0_34.inp: File for a TIM system constructed from double-skewed, truncated tetrahedra shaped building blocks. Skew angle is 17 degree. An assembly of 10 x 10 blocks. BT2_tet_i12_0_34.inp: File for a TIM system constructed from double-skewed, truncated tetrahedra shaped building blocks. Skew angle is 17 degree. An assembly of 12 x 12 blocks. BT2_tet_i5_0_34.inp: File for a TIM system constructed from double-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 5 x 5 blocks. BT2_tet_i7_0_34.inp: File for a TIM system constructed from double-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 7 x 7 blocks. BT2_tet_i9_0_34.inp: File for a TIM system constructed from double-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 9 x 9 blocks. BT2_tet_i11_0_34.inp: File for a TIM system constructed from double-skewed, truncated tetrahedra shaped building blocks. Skew angle is 12 degree. An assembly of 11 x 11 blocks. 

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5. InP MOSFETs Exhibiting Record 70 mV/dec Subthreshold Swing

   Tseng, Hsin-Ying; Fang, Yihao; Zhong, Shibo; Rodwell, Mark (June 2019, 2019 IEEE Device Research Conference)

   Low InP/dielectric interface trap density Dit will enable low subthreshold swings (SS) in mm-wave MOSFETs [1] using InGaAs/InP composite channels [2] for increased breakdown and in tunnel FETs (TFETs) [3] using InAs/InP heterojunctions [4] for increased tunneling probability. Reducing Dit at the etched InP mesa edges of DHBTs and avalanche photodiodes will reduce leakage currents and increase breakdown voltages. While it can be difficult [5] to extract Dit of III-V interfaces from MOSCAP characteristics, Dit can be readily determined from the SS of long gate length Lg MOSFETs. Here we report InP-channel MOSFETs with record low SS indicating record low Dit at the semiconductor-dielectric interface. The devices use a AlOxNy/ZrO2 gate dielectric and a 14nm channel thickness Tch. A sample of 13 MOSFETs at 2 m Lg shows SS=70mV/dec. (mean) ±3 mV/dec. (standard deviation), corresponding to a minimum Dit ~3×1012 cm-2eV-1. The lowest SS observed at 2 m Lg is 66 mV/dec. The results suggest that wide-bandgap InP layers can be incorporated into MOS device designs without large degradations in DC characteristics arising from interface defects 

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