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101.
采煤工艺作为煤矿正常生产的核心,直接关系到综采作业的效率、煤炭回采率和综采作业的安全性,随着对综采作业要求的不断提高,旋转式采煤工艺在煤矿井下的应用范围也不断扩大。以黄家沟煤业1205综采作业面为分析对象,对旋转式采煤工艺在井下的应用情况进行了研究,为优化综采方法、提升综采作业效率和煤炭回采率奠定基础。 相似文献
102.
103.
In this work, we report the development of MnO2/F-MWCNT/Ta hybrid nanocomposite sensor with different MnO2 overlayer thickness for the detection of H2O2 in real samples. A novel two-step process using e-beam evaporation and spray pyrolysis deposition was adopted for the synthesis of hybrid MnO2/F-MWCNT/Ta electrodes. SE morphology revealed smaller-sized, compact grains of MnO2 infiltrated on the outermost walls of MWCNTs. Raman analysis confirmed the existence of carbon nanotubes with abundant structural defects of MnO2 in the composite. The cyclic voltammetry results displayed a high peak current and narrowed over potential towards the reduction of H2O2. The sensor displayed a fast response (<5?s), wide linear range (2–1510?μM) and a low limit of detection (0.04?μM) with significant anti-interfering properties, promising for the development of highly sensitive and reproducible biosensors. The three dimensional nanocomposite sensor also exhibited good recovery (> 98%), thus providing a favourable tool for analysis of H2O2 in milk samples. 相似文献
104.
Kamran Zaheer 《Drug development and industrial pharmacy》2018,44(3):444-451
Food induced viscosity can delay disintegration and subsequent release of API from solid dosage form which may lead to severe reduction in the bioavailability of BCS type III compounds. Formulations of such tablets need to be optimized in view of this postprandial viscosity factor. In this study, three super disintegrants, croscarmellose sodium (CCS), cross-linked polyvinylpolypyrrolidone (CPD), and sodium starch glycolate (SSG) were assessed for their efficiency under simulated fed state. Tablets containing these disintegrants were compressed at 10 and 30?KN, while taking lactose as a soluble filler. In addition to other compendial tests, disintegration force of these formulations was measured by texture analysis. Comparison of parameters derived from force – time curves revealed a direct relation of maximum disintegration force (Fmax) and disintegration force development rate (DFDR) with compressional force in fasted state, whereas an inverse relationship of Fmax and DFDR with compressional force was observed in fed state. The gelling tendency of disintegrants influenced the rate of release of API in simulated fed and fasted states when compressional force was changed. These observations recommend the evaluation of formulations in simulated fed state, in the development stage, with an objective of minimizing the negative impact of food induced viscosity on disintegration. Use of disintegrants that act without gelling or can counteract the effect of gelling is recommended for tablet formulations with reduced disintegration time (DT) and mean dissolution time (MDT) in fed state, respectively. 相似文献
105.
《Advanced Powder Technology》2020,31(1):287-299
The parameters governing the crystallisation of paracetamol using various conventional techniques has been extensively studied, however the factors influencing the drug crystallisation using spray drying is not as well understood. The aim of this work was to investigate the crystallisation of an active pharmaceutical ingredient through evaporative crystallisation using a spray dryer to study the physicochemical properties of the drug and to use semi-empirical equations to gain insight into the morphology and particle size of the dried powder. Paracetamol solutions were spray dried at various inlet temperatures ranging from 60 °C to 120 °C and also from a series of inlet feed solvent compositions ranging from 50/50% v/v ethanol/water to 100% ethanol and solid-state characterisation was done. The size and morphology of the dried materials were altered with a change in spray drying parameters, with an increase in inlet temperature leading to an increase in particle Sauter mean diameter (from 3.0 to 4.4 µm) and a decrease in the particle size with an increase in ethanol concentration in the feed (from 4.6 to 4.4 µm) as a result of changes in particle density and atomised droplet size. The morphology of the dried particles consisted of agglomerates of individual crystallites bound together into larger semi-spherical agglomerates with a higher tendency for particles having crystalline ridges to form at higher ethanol concentrations of the feed. 相似文献
106.
《中国稀土学报(英文版)》2020,38(11):1190-1200
Herein, a new mechanism involving Lewis acid-oxygen vacancy interfacial synergistic catalysis for aniline N,N-diethylation with ethanol was proposed, and the SO42−/Ce0.84Zr0.16O2–WO3–ZrO2 catalyst (SCWZ) with both Lewis acid sites and oxygen vacancies was synthesized by the hydrothermal method, which shows better catalytic activity than the reported solid acidic catalysts. Besides, the SO42−/ZrO2 (SZ) and SO42−/WO3–ZrO2 (SWZ) catalysts were also prepared and compared with SCWZ to investigate the synergistic effect of each component. The SO42− and WO3 mainly generate Lewis acid by bonding with ZrO2, which is beneficial for the fracture of the N–H bond in aniline. The Ce0.84Zr0.16O2 solid solution mainly plays a vital role in generating the oxygen vacancies as the interface active species, which can participate in stripping –OH from ethanol, then the carbocation will also be released, which only needs 1.3805 kcal/mol energy, calculated by density functional theory (DFT), to be input. In comparison, the traditional reaction mechanism needs the Brønsted acidic sites to promote the protonation of ethanol, then dehydration and subsequent formation of carbocation followed, and 108.6846 kcal/mol energy needs to be input, which is far higher than that of the new mechanism. The apparent activation energy (Ea) over SCWZ was measured by experiment to be 34.09 kJ/mol, which is much lower than that of SWZ (47.10 kJ/mol) and SZ (54.37 kJ/mol), illustrating comparatively preferable kinetics for SCWZ than that of SWZ and SZ. Besides, the conversion of aniline and selectivity to N,N-diethylaniline over SCWZ reach almost 100% and 73%, respectively. The SCWZ can be renewed for 4 times without rapid deactivation, and the longevity of SCWZ is longer than that of SWZ and SZ, as the loaded SO42− and tetragonal ZrO2 are stabilized by Ce0.84Zr0.16O2 and WO3, respectively. 相似文献
107.
As a novel virtual reality (VR) format, panorama maps are attracting increasing attention, while the compression of panorama images is still a concern. In this paper, a densely connected convolutional network block (dense block) based autoencoder is proposed to compress panorama maps. In the proposed autoencoder, dense blocks are specially designed to reuse feature maps and reduce redundancy of features. Meanwhile, a loss function, which imports a position-dependent weight item for each pixel, is proposed to train and adjust network parameters, in order to make the autoencoder fit to properties of panorama maps. Based on the proposed autoencoder and the weighted loss function, a greedy block-wise training scheme is also designed to avoid gradient vanishing problem and speed up training. During training process, the autoencoder is divided into several sub-nets. After each sub-net is trained separately, the whole network is fine-tuned to achieve the best performance. Experimental results demonstrate that the proposed autoencoder, compared with JPEG, saves up to 79.69 % bit rates, and obtains 7.27dB gain in BD-WS-PSNR or 0.0789 gain in BD-WS-SSIM. The proposed autoencoder also outperforms JPEG 2000, HEVC and VVC in both BD-WS-PSNR and BD-WS-SSIM. Meanwhile, subjective results show that the proposed autoencoder can recover details of panorama images, and reconstruct maps with high visual quality. 相似文献
108.
摘要:对腿部运动意图识别算法的实时性能进行综合可靠的评价是实现下肢假肢灵活稳定控制的前提。提出一种逐层分级的基于下肢运动意图识别算法的实时测评方法,对算法的可靠性、稳定性以及运动意图识别速度进行综合评价。利用开发的运动意图识别算法评测系统,对基于肌电信号源和机械信号源的两种运动意图识别算法进行了实时性能测试,发现肌电信号源的算法识别时间大于机械信号源算法,但是其算法稳定性优于机械信号源算法。进一步地,还利用该评测系统有效地区分出正常识别策略与异常识别策略,发现正常策略的动作识别稳定系数比异常策略高25%左右。因此,所提的基于下肢运动意图识别算法的实时测评方法,能够对不同信号源算法以及不同识别策略的实时性能进行有效评价,为智能下肢假肢控制系统开发提供可供参考的测试平台。 .txt 相似文献
109.
通过对紫金山东南矿段铜钼(金)矿床地质矿化特征分析,指出铜钼矿化带主要赋存于花岗闪长斑岩的内外接触带,处于似斑状花岗闪长斑岩的上部,金矿化带赋存在表生氧化带的英安玢岩、隐爆角砾岩中。经过对矿石的组构特征、矿物生成顺序等特征分析,将矿床的成矿演化过程分为斑岩热液期、高硫化浅成低温热液期、表生氧化期三个主要矿化期次,进一步将斑岩热液期分为黑云母-钾长石化阶段、石英-绢云母化阶段、碳酸盐化阶段三个阶段;高硫化浅成低温热液期分为地开石化阶段、明矾石化阶段、硅化阶段三个阶段。研究结果为进一步研究矿床成因提供了依据。 相似文献
110.