约束连接在球墨铸铁管施工中的应用

采用球墨铸铁管的约束连接形式,可不设支墩。介绍了其连接形式、安装方法、使用长度以及在工程中的应用情况。同时介绍了其在穿越渠道及在三通、弯头等特殊地段的使用,并与标准支墩工法作了技术经济比较。     

聚四亚甲基醚二醇羟值含量的测定

介绍使用乙酸酐-N-甲基咪唑-二甲基甲酰胺催化酰化法测定聚四亚甲基醚二醇(PTMEG)的羟值含量,讨论了样品用量、酰化温度、酰化时间和酰化剂含水量及稳定性对测定结果的影响.结果表明:使用乙酸酐-N-甲基咪唑-二甲基甲酰胺催化酰化体系,在50℃下酰化反应时间30 min,测得PTMEG1000和PTMEG2000羟值结果...     

纤维素结合域的引入对角质酶在纤维素类纤维上吸附性能的影响

为了研究纤维素结合域（Cellulose-binding Domain,CBD）的引入对角质酶在纤维素类纤维上吸附能力的影响,本文选用漂白棉织物、粘胶纤维、醋酯纤维以及纯棉针织坯布这四种材质,对角质酶与CBD-角质酶进行吸附对比试验。研究表明：CBD结构的引入,可提高角质酶在纤维素纤维上的吸附量。但是当纤维素葡萄糖残基上羟基被部分酯化后,CBD结构的引入对吸附量造成的影响开始减弱,而当纤维素纤维表面被疏水性杂质覆盖时,CBD-角质酶对纤维素纤维的吸附能力反而降低。     

晨光机床掌控国际炭素装备话语权

中国历来是高精密制造设备进口国,晨光公司高档数控炭素装备生产线的高调出口,堪称我国企业界创新发展的典范。近日,地处苏中大平原扬子江畔的泰兴市晨光高新技术开发有限公司门前披红挂绿,彩旗飘扬,鞭炮齐鸣,戒     

稀土元素上转换材料在钙钛矿太阳能电池中应用的研究进展

无机有机杂化钙钛矿太阳能电池被认为是最有发展前景的第三代光伏技术之一,经过短短几年时间的研究,钙钛矿太阳能电池现今的最高效率已经突破22%.随着钙钛矿太阳能电池的效率越来越接近理论效率,为了进一步提升电池效率,研究人员将目光投向了钙钛矿材料不能有效吸收的近红外波段.在本文中,我们回顾了近两年来将上转换材料与钙钛矿太阳能电池相结合的研究,将它们分成较为传统的方法和新型方法.传统的方法即是使用较为单一的NYF纳米颗粒对钙钛矿太阳能电池进行掺杂,利用稀土离子的上转换效应,吸收近红外光,扩宽钙钛矿的吸收范围,从而提升太阳能电池的性能;而新型的方法即是在传统的单一使用稀土离子的基础上,添加其他离子或者引入重掺杂半导体材料来进一步提升太阳能电池性能的方法,从实验结果看,这两种方法都取得了较好的结果.     

Research on image segmentation of Miao costume patterns based on the RSKP-UNet model北大核心CSCD

The Miao nationality is the sixth largest ethnic group in China which has a history of thousands of years. It has created a unique material culture and spiritual culture in its development process and the Miao costume is a highly condensed collection of the material and spiritual culture of the Miao nationality. As one of the unique symbols of Miao culture the Miao costume has profound cultural heritage and cultural connotations. The patterns of the Miao costume are particularly eye-catching as they not only symbolize the wisdom of the Miao people in thousands of years of production and life but also symbolize the pursuit of the good spirit of the Miao people. However under the impact of modern pop culture and foreign culture these cultural symbols are gradually disappearing. In order to protect and inherit them the Miao costume pattern segmentation has become the most important work. However the Miao costume pattern segmentation is quite difficult. At present there are few studies on the extraction classification identification and preservation of the features of Miao costume pattern segmentation. With the excellent segmentation performance of the U-Net model and the advantages of easy deployment the paper improves the basic structure of the U-Net model and proposes a Miao costume pattern segmentation algorithm based on the RSKP-UNet Residual Selective-Kernel Parallel U-Net model. The algorithm adds Residual modules in the encoder part of the U-Net model to improve the feature extraction capability of the model and embeds the SKNet modules and ParNet modules in the decoder part to enhance the feature expression capability of the model. The paper uses evaluation metrics to measure the segmentation performance of the model and compares it with four segmentation models based on deep learning. The paper not only combines the current research focus-deep learning and attention mechanism but also introduces the Lovász-hinge loss function to effectively solve the problem of class imbalance in the Miao costume patterns. The RSKP-UNet model is better than other models in various segmentation indicators. Compared with the benchmark model U-Net the Dice coefficient IoU precision recall and accuracy are improved by 6. 98% 11. 07% 2. 89% 6. 75% and 3. 92% . The segmentation algorithm proposed in this paper realizes the extraction of the element content of the Miao costume patterns through image segmentation of Miao costume patterns which can be used to build the Miao costume pattern database in this way thus helping designers relevant researchers and organizations to provide research foundation and completing the protection and inheritance of the Miao costume culture. The paper also provides some reference for the segmentation research of other minority costume patterns. © 2022 Authors. All rights reserved.     

孕甾烷X受体在药物代谢中的作用及研究进展

孕甾烷X受体(Pregnane X receptor, PXR)为核受体超家族中NR1I亚家族成员,于肝脏和肠道中广泛表达。该受体作为药物代谢的关键调控因子广泛参与药物的吸收、分布、代谢及排泄过程。本文从药物代谢角度分别对PXR参与调节的Ⅰ、Ⅱ相代谢酶及转运体进行介绍,为临床药物相互作用及针对PXR为靶点的药物研发提供参考。     

溶液中碳酸氢根在线分析仪的研制

针对CO_2+O_2原地浸出采铀方法中碳酸氢根质量浓度的测定需求,研制了一种溶液中碳酸氢根在线分析仪。介绍了在线分析仪的测定原理、硬件和试剂配制,并对测试流程进行了详细说明。研制的在线分析仪实现了对0~2 000mg/L碳酸氢根质量浓度的测定,对在线分析仪进行的连续测试表明,仪表运行稳定,重复性好,精密度高,与现场手工分析基本一致,加标回收率在97.3%~103%,可满足现场碳酸氢根质量浓度连续、实时监测的需求。在线分析仪不仅可用于地浸采铀中碳酸氢根质量浓度的测定,还可应用于其他领域的相关测定,具有良好的实用性。     

软管泵在浮选给矿系统上的应用与改进

铅锌公司在近几年生产实践中,浮选系统一直采用自制稳压给矿箱供矿,给矿系统不均匀、不稳定,存在断流现象,通过对给矿系统考察论证,软管泵工作原理,应用后的优点,改进的技术措施等的分析,充分说明了软管泵在给矿系统中应用给公司可带来可观的经济效益和环境效益。     

论舞蹈的情感表现

随着社会的进步,舞蹈也有了欧足的发展,舞蹈编创的各个环节都要为舞蹈形象服务,传达出情感!只有这样,作品才能具有艺术性,才能具有艺术的感染力。