Electromechanical coupled nonlinearity and critical velocity for electromagnetic railgun

The nonlinear electromagnetic force can change the critical velocity of the projectile for a railgun. It corresponds to the resonance state in railgun. Here, the nonlinear electromechanical coupled dynamics equations for the railgun are proposed. Based on it, the equation of the nonlinear critical velocity of the projectile is given and the effects of the electromagnetic nonlinearity on the critical velocity of the projectile are investigated. Besides it, the effects of the fire velocity on the nonlinear critical velocity are studied as well. Results show that the critical velocity of the railgun system increases when the electromagnetic nonlinearity is considered, and the nonlinear critical velocity is influenced by the system parameters such as rail current, rail thickness, rail distance, etc. A FEM analysis package, ANSYS, is used to simulate dynamics performance of the railgun system and illustrate the analytical results about critical velocities of the railgun system. The results can be used to design dynamics performance of the railgun system

Mineralogical characterization of manganese oxide minerals of the Devonian Xialei manganese deposit

The Guangxi Zhuang Autonomous Region is an important manganese ore district in Southwest China, with manganese ore resource reserves accounting for 23% of the total manganese ore resource reserves in China. The Xialei manganese deposit (Daxin County, Guangxi) is the first super-large manganese deposit discovered in China. The Mn oxide in the supergene oxidation zone of the Xialei deposit was characterized using scanning electron microscopy (SEM), energy spectrometer (EDS), transmission electron microscopy (TEM, HRTEM), and X-ray diffraction analysis (XRD). The Mn oxides have a gray-black/steel-gray color, a semi-metallic-earthy luster, and appear as oolitic, pisolitic, banded, massive, and cellular textures. Scanning electron microscopy images show that the manganese oxide minerals are present as fine-spherical particles with an earthy surface. TEM and HRTEM indicate the presence of oriented bundled and staggered nanorods, and nanopores between the crystals. The Mn oxide ore can be classified into two textural types: (1) oolitic and pisolitic (often with annuli) Mn oxide, and (2) massive Mn oxide. Pyrolusite, cryptomelane, and hollandite are the main Mn oxide minerals. The potassium contents of cryptomelane and pyrolusite are discussed. The unit cell parameters of pyrolusite are refined

A Vertically-Aligned Lcos With Submillisecond Response Time

We demonstrated a TFT-grade fluorinated, UV-stable, high birefringence and low viscosity negative Δε LC mixture and characterized its physical properties. With this mixture in a thin-cell-gap LCOS, we can achieve submillisecond response time at an elevated temperature, which enables color sequential projection displays without noticeable color breakup. © 2013 Society for Information Display

Classification, grading criteria and quantitative expression of earth fissures: a case study in Daming Area, North China Plain

Observation, description and preliminary analysis are important means in studies on earth fissures. As a phenomenon of surface fractures, earth fissures are formed under the joint action of exogenetic and endogenetic forces and their development can be characterized by parameters of length, width, depth, fractal dimension and influential width. Based on their length, we deduced a ‘length-grade conversion equation’ and divided earth fissures into 10 grades. In addition, we also deduced a series functions to describe the contribution of fissure-inducing forces including active fault, earthquake, groundwater withdrawal and ancient river channels based on their roles in fissure formation and their affecting conditions. These functions provide the criteria for classification of earth fissures. In order to verify the effectiveness of these methods, we took Daming fracture zone on the North China Plain as an example to quantitatively calculate the control factors of the earth fissures in this area. Moreover, we proposed various plane expression methods for single and grouped earth fissures that could be used to improve the relevant studies on earth fissures

A Vertically-Aligned LCOS with Submillisecond Response Time

Abstract We demonstrated a TFT-grade fluorinated，UV-stable, high birefringence and low viscosity negative Δε LC mixture and characterized its physical properties. With this mixture in a thincell-gap LCOS, we can achieve submillisecond response time at an elevated temperature, which enables color sequential projection displays without noticeable color breakup

A novel polymer donor based on dithieno[2,3-d:2 ',3 '-d '']benzo[1,2-b:4,5-b ']dithiophene for highly efficient polymer solar cells

A novel polymer donor based on dithieno[2,3-d:2 ',3 '-d '']benzo[1,2-b:4,5-b ']dithiophene for highly efficient polymer solar cell

Efficient Enhancement of Electron Transport and Collection Capability in PTB7:PC71BM-based Solar Cells Enabled by Sulforhodamine Cathode Interlayers

Efficient Enhancement of Electron Transport and Collection Capability in PTB7:PC71BM-based Solar Cells Enabled by Sulforhodamine Cathode Interlayer

The Application of EPMA in the Textural Characterization of Cryptomelane in the Xialei Manganese Deposit, Southwest Guangxi

BACKGROUND: OMS-2 has shown great significance in ion exchange, catalyst, energy and environment, but the research of natural OMS-2 mineral material cryptomelane is still lacking in the detailed characterization of the composition, structure and genetic research. Annulus and core-rim structures are representative in the structure of manganese oxide minerals. It is of great significance to clarify the mineral species and explore its composition characteristics, its origin and develop the application of manganese oxides. The Mn ore resource of Guangxi account for 23% of the manganese ore resource reserves in China. The Xialei Mn deposit located in Southwest Guangxi is the earliest super-large Mn deposit discovered in China, with an average grade of about 30% for the manganese oxide ore. OBJECTIVES: To explore the annulus and core-rim texture and its composition of cryptomelane in the Xialei Mn deposit.METHODS: Quantitative analysis and element mapping of EPMA and microscopy were carried out.RESULTS: The element intensity of the cryptomelane with annulus texture was Mn, K, Mg, Al, Zn, Ba, P, Fe in order of average from strong to weak. The average element intensity of the cryptomelane with core-rim texture was Mn, K, Ca, Mg, Zn, Ba, P, Fe from strong to weak. The K content gradually increased (2.31%-4.17%, 0.38-0.62 atoms per formula unit) from the middle to the rim of the cryptomelane, indicating K enrichment during oxidization and the stable status of Mn oxides.CONCLUSIONS: The change in the trend of K and Mn ions is the direct cause of the formation of the annulus and core-rim texture, reflecting the changes of oxidation environment. Potassium content gradually increases from the inner to outer zone, which may indicate the enrichment of potassium during the oxidation process, and also reflects manganese oxide gradually tending to the most stable state

13.34 % Efficiency Non-fullerene All-Small-Molecule Organic Solar Cells Enabled by Modulating the Crystallinity of Donors via a Fluorination Strategy

Non-fullerene all-small-molecule organic solar cells (NFSM-OSCs) have shown potential as OSCs, owing to their high purity, easy synthesis and good reproducibility. However, challenges in the modulation of phase separation morphology have limited their development. Herein, two novel small molecular donors, BTEC-1F and BTEC-2F, derived from the small molecule DCAO3TBDTT, are synthesized. Using Y6 as the acceptor, devices based on non-fluorinated DCAO3TBDTT showed an open circuit voltage (V-oc) of 0.804 V and a power conversion efficiency (PCE) of 10.64 %. Mono-fluorinated BTEC-1F showed an increased V-oc of 0.870 V and a PCE of 11.33 %. The fill factor (FF) of di-fluorinated BTEC-2F-based NFSM-OSC was improved to 72.35 % resulting in a PCE of 13.34 %, which is higher than that of BTEC-1F (61.35 %) and DCAO3TBDTT (60.95 %). To our knowledge, this is the highest PCE for NFSM-OSCs. BTEC-2F had a more compact molecular stacking and a lower crystallinity which enhanced phase separation and carrier transport