摘要：Based on analysis of thermo-hydro-mechanical-chemical(THMC)coupling mechanism for brittle rock,THMC coupling indicator in terms of rock porosity was introduced to represent the influencing degree of THMC coupling field on stress field in order to establish THMC coupling fracture criterion.A novel real-time measurement method of permeability(related to porosity)was proposed to determine the THMC coupling indicator,and self-designed THMC coupling tests and scanning electron microscope tests were conducted on pre-cracked red sandstone specimens to study the macroscopic and microscopic fracture *** results show that the higher the hydraulic pressure is,the smaller the crack initiation load is and the easier the Mode I fracture *** results are in good agreement with prediction results(crack initiation load and angle,and fracture mode),which can verify the effectiveness of the newly established THMC coupling fracture *** new fracture criterion can be also further extended to predict THMC coupling fracture of multi-crack problem.

摘要：The dynamics anMysis of recurrent neural networks （RNNs） is a first and necessary step for any practical applications of them. In the present paper, the easily verified theorem is found to ascertain the asymptotical stability for generic RNN model with projection mapping under the critical condition that a discriminant matrix defined by the networks is semi-positive definite. The results given here not only improve deeply upon the existing relevant critical as well as non-critical dynamics conclusions in literature, but also can be used in the practical application of RNNs directly.

摘要：目的建立基于自研模体的磁共振加速器日检质控流程,验证该设备束流精度、MR图像引导精度和临床治疗工作流程,评估其提高日检效率的作用。方法设计并3D打印与Daily QA-MR探测器矩阵联合使用的自研模体,对其进行CT扫描、计划设计并传输至加速器端进行临床治疗工作流程质控,对图像引导精度及输出量、射线质等束流输出检测项目进行检测。采用配对样本t检验方法比较基于自研模体的日检流程和基于厂家推荐的标准模体日检流程的结果差异。结果共采集到24组测试结果,标准模体的MR图像引导精度在X、Y、Z方向上偏差分别为(0.1±0.4)、(-0.14±0.16)、(0.07±0.05)mm,自研模体分别为(0±0.02)、(-0.02±0.02)、(0.02±0.01)mm,差异有统计学意义(P<0.001、=0.001、<0.001);Daily QA-MR探测器矩阵对输出量、枪靶对称性、射线质变化、Y方向射野大小、Y方向射野中心偏移的检测结果分别为-0.11%±0.20%、-0.10%±0.19%、-0.01%±0.08%、(0.4±0.1)mm、(0.2±0.1)mm;采用新流程较标准流程能节省25%(约9 min)的时间。结论基于Daily QA-MR探测器矩阵联合自研模体,利用本文提出的方法进行磁共振加速器日检,其准确性和灵敏度满足检测要求并且能够提升日检效率。

摘要：为了更好地满足液化天然气(LNG)行业对高性能低温调节阀的需求,本文设计出一种新型低温球形调节阀。该阀门的公称通径为NPS 4、公称压力为ANSI Class 900,能够在-196℃的极端低温环境下稳定工作。本文深入探讨了阀门的关键技术,包括调节原理、低温材料的选择与处理、结构设计及性能仿真,并优化了阀芯、先导结构和压力平衡设计;介绍了产品的检验与性能测试流程,以确保其在投产后的安全性和可靠性。最后,总结出设计过程中面临的挑战及解决策略,包括高压差下的密封有效性、开启问题以及介质力引起的阀杆不平衡力问题。

摘要：目的 :获得适于大肠杆菌表达的人γ干扰素(hIFN -γ)基因。方法 :用大肠杆菌偏嗜性密码子替换已知hIFN -γ基因编码序列中相应的密码子,将重新设计后的编码序列分为六段进行人工化学合成,通过PCR拼接技术扩增出大肠杆菌偏嗜性hIFN -γ基因编码序列 ,并进行克隆及序列分析。结果 :经序列分析证实 ,重组pGEM-hIFN -γ质粒含有与预期结果一致的hIFN -γ基因编码序列。结论 :成功进行了大肠杆菌偏嗜性hIFN -γ基因的克隆,为hIFN

摘要：为建立可视化检测牛传染性鼻气管炎病毒(IBRV)的酶促恒温扩增-侧向流动试纸(ERA-LFD)方法,根据IBRV gB基因的保守区域设计并筛选最佳引物和探针,通过优化反应条件建立IBRV ERA-LFD方法,并对其特异性、敏感性、重复性和符合性进行评估。结果显示,采用建立的方法检测牛呼吸道合胞体病毒、牛病毒性腹泻病毒、牛冠状病毒、多杀性巴氏杆菌、弓形虫均无交叉反应,特异性强;建立方法最低检出IBRV阳性质粒的量为1.63×10^(1) copies/μL,比PCR方法高100倍,敏感性高;对相同样品进行批间和批内检测,结果均一致,重复性好;ERA-LFD与PCR方法检出的符合率为96%,且测序证实ERA-LFD检测结果无误。IBRV ERA-LFD的临床样本检测结果显示阳性率为2.08%,与PCR方法的结果相一致,说明IBRV ERA-LFD方法适于临床样品检测,为IBRV的临床快速检测和流行病学调查提供了工具。

摘要：采用拉索索端阻尼器是大跨度斜拉桥拉索减振的主要措施之一。现有拉索阻尼器设计理论均假定索的两端为固结;然而,随着斜拉桥跨度的增大,桥梁结构整体刚度下降,主梁振动对拉索附加阻尼器减振效果的影响成为大跨度斜拉桥拉索减振设计需要考虑的问题。该文建立了索、梁和阻尼器组合系统的简化理论模型,并对其进行了复模态分析。以跨径分别为400m、650m和1km的3座斜拉桥主跨最长索为算例,分析了主梁振动对拉索附加阻尼器减振效果的影响,指出了现有阻尼器设计理论的不足。分析结果表明:主梁振动降低了拉索附加阻尼器的减振效果;在大跨度斜拉桥拉索的减振设计中,必须考虑主梁参与振动的影响。

摘要：采用拉索索端阻尼器是大跨度斜拉桥拉索减振的主要措施之一。设计了索、梁和阻尼器组合系统的简化力学模型,研究了组合系统在具备不同力学特性时,主梁振动对拉索附加阻尼器减振效果的影响。分析结果表明,主梁振动降低了拉索附加阻尼器的减振效果;在大跨度斜拉桥拉索的减振设计中,尤其是对于有可能产生索、梁耦合大幅振动的拉索必须考虑主梁参与振动的影响。

摘要：The design and implementation of an online guide system were presented for *** system offers a website that makes it easier for patients,or any ordinary visitor to diagnose their disease by simply uploading their MRI image,the website also assists the patient in determining the doctor they need to see,and finding the nearest hospital or blood *** build the website,SQL Server,MAT-LAB,and Adobe Dreamweaver were *** rapid increase in digital images produced in hospitals us-ing medical imaging techniques such as X-Ray,CT scans,MRI,and ultrasound has increased the demand for efficient image retrieval *** description,and annotation of each image in a large database using text-based indexing(also known as the Metadata approach)is time-consuming,and impractical,making Content-based Image Retrieval(CBIR)a better *** system proposed returns results based on visual features of the image,such as color,texture,and shape.

摘要：针对声矢量传感器姿态变化难以准确测量导致目标测向精度低的现状,设计一种微型MEMS姿态传感器,并将其封装在声矢量传感器内部,实现基于MEMS姿态传感器的声矢量传感器设计。首先根据声矢量传感器姿态测量与校正原理,采用四元数姿态解算方法及扩展卡尔曼滤波器设计MEMS姿态传感器,并对其进行姿态精度测试;然后基于MEMS姿态传感器进行声矢量传感器样机设计、制作、参数测试;最后对样机进行了海上实验,结果表明,通过姿态校正后声矢量传感器目标方位估计精度与GPS推算方位精度一致,验证了利用MEMS姿态传感器设计声矢量传感器的可行性。