Abstract: The present disclosure provides methods, systems and apparatus for efficient data management in distributed database system. According to an aspect, a method is provided. The method includes relocating a first table and a second table of a database to a first node of the database, wherein the first table and a second table (or one or more tables which have a colocation relationship with the first table) are associated with one or more distribution keys corresponding to one or more columns of the first table and the second table. The method further includes defining a colocation relationship between the first table and the second table based on a distribution key of the one or more distribution keys. The colocation relationship may indicate that data of the first table and the second table that correspond according to the distribution key are to reside on a same node of the database.

Abstract: Systems and methods for assessing and predicting corporate performance based on social media content are disclosed. For each individual, processor(s) are configured to chronologically sort a respective employment history. For each period-of-time within a period-of-interest, the processor(s) are configured to generate a respective company index score for each company based on a percentile rank of a respective metric value for a metric-of-interest relative to a respective set of benchmark companies; identify which individual(s) are associated with the reference company based on respective employment histories; for each individual associated with the reference company, calculate a respective individual index score based on the respective company index scores of the reference company and preceding company index scores of preceding companies-of-employment; and for the reference company, calculate a collective index score based on the individual index scores of the individuals associated with the reference company.

Abstract: One aspect of the present invention is concerned with a method of preparing a catalyst for use in synthesizing ammonia from nitrate. The method has the steps of i) providing a nickel foam material, ii) removing an oxide layer on the nickel foam material, iii) subjecting the nickel foam material to cooper sulphate (Cu2SO4) solution for a predetermined period of time for forming a copper (Cu) dopped nickel foam electrode, and iv) subjecting the Cu dopped nickel foam electrode to an annealing treatment at a predetermined temperature for a predetermined period of annealing time in atmospheric air thus forming a catalyst of copper oxide-nickel oxide nickel foam (CuO/NiO@NF) with a heterostructure. Other aspects of the invention are concerned with a method of preparing an electrolytic cell for use in synthesizing of ammonia, and a method of synthesis of ammonia from nitrate.

Abstract: The surface of low-dimensional perovskites plays a crucial role in determining their intrinsic properties. Thus, specific surfaces may be designed to obtain a desired characteristic and/or a functional structure. Further, surface passivation could also be applied to stabilize and optimize the state-of-the-art perovskite-based optoelectronics. CsPbBr3 microwires parallel arrays with specific (100)-terminated crystal planes were designed and fabricated to have excellent photodetection performance with long-term environment stability over 3000 hours. Further, environmental oxygen may be used to passivate the Br-vacancy-related trap states on the (100) surface and to create charge carrier nanochannels to enhance the (opto)electronic properties. The coupling effects between oxygen species and the specific terminated crystal planes of perovskites highlight the importance of surface engineering for designing and optimizing perovskite-based devices.

Abstract: In this invention, a high-performance photodetector based on 2D bilayered hybrid lead halide perovskite single crystal with ACI phase, with a chemical formula of GAMA2Pb2I7 where GA is C(NH2)3 and MA is CH3NH3,) was fabricated, using a facile and cost-effective method based on cooling crystallization. The single-crystal photodetector exhibits high photoresponsivity, together with correspondingly high detectivity values. Meanwhile, a high-resolution imaging sensor is built based on the GAMA2Pb2I7 single-crystal photodetector, confirming the high stability and photosensitivity of the imaging system.

Abstract: Systems and methods for identifying corporate targets based on social media content are disclosed. Users of a social media platform include individuals and companies. Each user has a user profile. For each individual, processor(s) generate individual data terms from the user profile and identify a current employer. For each company, the processor(s) generate company data terms from the user profile and add the individual data terms of the individuals for which the company is identified as the current employer to the company data terms. For each combination of company and company data term, the processor(s) generate a frequency score. The processor(s) identify seed companies, candidate companies, and data-type(s)-of-interest. For each data-type-of-interest, the processor(s) calculate a respective similarity score for each combination of seed company and candidate company. The processor(s) determine the target companies based on similarity scores of each candidate company.

Abstract: Ternary heterostructure comprising Ni2P, MoNiP2, and MoP, wherein the ternary heterostructure comprises crystalline regions and amorphous regions useful as an electrocatalyst for alkaline hydrogen evolution reaction; a cathode and an electrochemical cell including the same; and methods of preparation and use thereof.

Abstract: Visible and infrared radiation photothermoelectric effect photodetectors are provided. The photodetectors are formed on substrates having a low thermal diffusivity of less than 0.05 mm2/sec. A thermoelectric metal chalcogenide film is formed on the low thermal diffusivity substrate. At least two symmetric electrodes are formed on the thermoelectric metal chalcogenide film such that the thermoelectric metal chalcogenide film forms a channel between the electrodes. The photodetector has a responsivity of at least approximately 65 V W?1 for 1550 nm illumination and a response time less than approximately ˜60 ms. The photodetector photoresponse is tunable via manipulation of local illumination. Examples of photodetectors use Bi2Se3, Bi2Te3, and SnSe2 on flexible polymeric substrates. By using large-area thermoelectric films with a photothermal detection mechanism, and modulating responsivity via thermal coupling, photodetector arrays for wearable electronics and integrated optoelectronic circuits may be created.

Abstract: A power converter includes a plurality of power switches connected in series between a system ground and an input voltage bus, wherein an upper power switch located between the input voltage bus and an output terminal of the power converter, and immediately adjacent to the output terminal of the power converter is configured as an isolation switch including two back-to-back connected diodes and a bulk terminal, and wherein a connection of the bulk terminal is reconfigurable, and a driver configured to drive the upper power switch immediately adjacent to the output terminal of the power converter.

Abstract: A catalyst in ammonia synthesis includes a first layer of metal monochalcogenide-based material; a second layer of metal monochalcogenide-based material stacked with and is spaced from the first layer of metal monochalcogenide-based material by a first distance; wherein the metal monochalcogenide-based material includes SnS. A method of preparing the catalyst and an electrochemical ammonia synthesizing device making use of the catalyst thereof are also addressed.

Abstract: A three-dimensional non-noble-metal-based electrocatalysis electrode structure is provided. The electrode structure includes one or more layers of fused and approximately aligned elongated electrocatalyst nanoparticles that include a non-noble metal alloy or non-noble metal compound. Anisotropic nanochannels are positioned between the fused and approximately aligned elongated electrocatalyst nanoparticles that are configured to transfer generated gas bubbles therethrough. The elongated electrocatalyst nanoparticles may be nanorods that may have a diameter of approximately 20 to 50 nanometers and a length of approximately 80 to 300 nanometers. The anisotropic nanochannels may have a channel width of approximately 50-150 nanometers. The non-noble metal may be one or more of iron, cobalt, nickel, copper, molybdenum, or tungsten.

Abstract: Electrocatalytic overall water splitting to generate hydrogen and oxygen is a green and sustainable approach with zero carbon emission, which is important for the future renewable energy landscape. The practical application of this approach is challenging due to the sluggish reaction kinetics of water activation at high current densities, which are hard to overcome. Although high-performance alkaline bifunctional electrocatalysts may be useful, current catalysts lack both activity and durability. One approach is to rationally design bifunctional two-dimensional (2D) heterostructures but obtaining an efficient and durable catalyst has proved difficult. The present disclosure relates generally to an electrocatalyst including a 2D heterostructure (Ru-CMOP), methods of making and using the same. The catalyst of the present disclosure is designed for high activity and good durability at industrial-level high current densities.

Abstract: Continuous miniaturization of semiconductor devices is the key to boosting modern electronics development. However, such downscaling strategy has been rarely utilized in photoelectronics and photovoltaics. Here, in this work, a full-vdWs 1D p-Te/2D n-Bi2O2Se heterodiode with a rationally-designed nanoscale ultra-photosensitive channel is reported. Enabled by the dangling bond-free mixed-dimensional vdWs integration, the Te/Bi2O2Se type-II diodes show a high rectification ratio of 3.6×104. Operating with 100 mV reverse bias or in a self-power mode, the photodiodes demonstrated excellent photodetection performances, including high responsivities of 130 A W?1 (100 mV bias) and 768.8 mA W?1 (self-power mode), surpassing most of the reports of other heterostructures. More importantly, a superlinear photoelectric conversion phenomenon is uncovered in these nanoscale full-vdWs photodiodes, in which a model based on the in-gap trap-assisted recombination is proposed for this superlinearity.

Abstract: A design of efficient and robust electrocatalysts for hydrogen evolution reaction (HER) under all pH conditions is provided. Especially, the present invention provides a yolk-shell nanostructure with Rh nanoparticles embedded in S, N co-doped carbon nanostructures prepared by a facile self-template method. The obtained nanostructures can achieve an extremely small overpotential of 10-20 mV at 10 mA cm?2, a Tafel slope of 20-30 mV dec?1, a TOF of 0.1-0.3 s?1 (at ?75 mV/RHE) and long-term durability more than 10 hours.

Abstract: Mixed-dimensional heterostructure nano-devices with multi-functionality for use in semiconductors. Specifically, a gate-tunable and anti-ambipolar phototransistor is devised based on 1D p-type GaAsSb nanowire/2D n-type MoS2 nanoflake mixed-dimensional van der Waals (vdW) heterojunctions. Methods of making the mixed-dimensional heterostructure nano-devices with multi-functionality, gate-tunability and anti-ambipolar phototransistor.

Abstract: Electrochemical conversion of nitrate to ammonia is an approach to alleviate nitrate pollution in water and simultaneously generate green NH3 fuels. The practical application of this approach is challenging due to the lack of efficient electrocatalysts. The present disclosure relates generally to an electrocatalyst including a plurality of CuWO4 hollow nanospheres, which include asymmetric oxygen vacancies and adjacent Mo clusters, and methods of making and using the same. The electrocatalyst of the present disclosure is designed for efficient ammonia electrosynthesis.

Abstract: A method of fabricating a halide perovskite having a general formula of ABX3, wherein A, B, and X are inorganic elements and X is a halide, the method including a vapor-liquid-solid process triggered by a catalyst formed from a halide precursor of inorganic element B. A ABX3 nanowire formed by the method and a photoelectronic device with the ABX3 nanowire.

Abstract: A light-emitting device includes a semiconductor laminate, a first electrode and a second electrode. The semiconductor laminate has a mesa surface, an upper surface, a connecting surface that connects the upper surface and the mesa surface, and a lower surface opposite to the mesa surface and the upper surface. The semiconductor laminate includes a first semiconductor layer, an active layer, and a second semiconductor layer disposed in such order in a direction from the lower surface to the upper surface. The semiconductor laminate has at least one trench that extends from the mesa surface into the first semiconductor layer. The first electrode is electrically connected to the first semiconductor layer and formed on the mesa surface, and has an extending portion that extends into the trench. The second electrode is electrically connected to the second semiconductor layer and formed on the upper surface.

Abstract: A method of fabricating a halide perovskite having a general formula of ABX3, wherein A, B, and X are inorganic elements and X is a halide, the method including a vapor-liquid-solid process triggered by a catalyst formed from a noble metal; A nanowire of the halide perovskite and a photoelectronic device thereof

Abstract: The large-scale artificial synaptic device arrays based on the organic molecule-nanowire heterojunctions with tunable photoconductivity are proposed and demonstrated. The organic thin films of p-type 2,7-dioctyl[1]benzothieno[3,2-b][1] benzothiophene (C8-BTBT) or n-type phenyl-C61-butyric acid methyl ester (PC61BM) are used to wrap the InGaAs nanowire parallel arrays to configure two different type-I heterojunctions, respectively. Due to the difference in carrier injection, persistent negative photoconductivity (NPC) or positive photoconductivity (PPC) are achieved in these heterojunctions. The irradiation with different wavelengths (solar-blind to visible ranges) can stimulate the heterojunction devices, effectively mimicking the synaptic behaviors with two different photoconductivities. Evidently, these photosynaptic devices are illustrated with retina-like behaviors and capabilities for large-area integration, which reveals their promising potential for artificial visual systems.