Subjects: Nuclear Science and Technology >> Other Disciplines of Nuclear Science submitted time 2024-05-07
Abstract： Smart-Cut technology is a technique of exploiting both ion implantation and wafer bonding to transfer ultrathin single-crystal layers from a donor substrate to a receiving substrate. In advanced microelectronic systems, as one of the important technical means of heterogeneous integration for semiconductor materials, Smart-Cut technology has been widely concerned by academia and industry. Smart-Cut technology is the process of implanting H+, He+ ions or co-implantation them into the surface of semiconductor materials, and adjusting the implantation parameters (energy, temperature, dose, dose rate, ion implantation sequence, etc.). After the bonding of implanted semiconductor material and substrate at low temperatures, annealing (temperature, time, rate) that generates microcracks parallel to the surface is performed to achieve layer transfer. In this paper, the research progress of the Smart-Cut technology used in the first-, second-, third- and fourth-generation semiconductors in the past two decades is summarized. The microstructure and microcracks nucleation and growth mechanisms are analyzed. The reasons for the exfoliation thresholds of different semiconductors are discussed. The paper is helpful for understanding the application of Smart-Cut technology used in the fabricating of semiconductor devices.
Subjects: Medicine, Pharmacy >> Clinical Medicine submitted time 2024-04-24 Cooperative journals: 《中国全科医学》
Abstract： Background Rifampicin-resistant/multidrug-resistant tuberculosis（RR/MDR-TB）is featured by challenges in the treatment，low cure rate，and high infectivity. Fluoroquinolones（FQs），as the core drugs for the treatment of RR/MDR-TB，have a severe trend of resistance. Analyzing influencing factors for FQs can help to increase the cure rate of RR/MDR-TB and to control the occurrence of the pre-extensive drug resistance（pre-XDR）and extensive drug resistance（XDR）. Objective To analyze the drug resistance of FQs in hospitalized patients with pulmonary tuberculosis and the influencing factors，and to construct and validate a Nomogram prediction model for the risk factors of drug resistance of FQs. MethodsA total of 583 patients with pulmonary tuberculosis who were hospitalized in Guiyang Public Health Clinical Center from January 2021 to February 2022 and tested for drug sensitivity were retrospectively selected as study subjects. They were divided into the initial treatment group（296 patients）and the retreatment group（287 patients）according to the history of previous treatment. Moreover，they were divided into the FQs-resistant group（63 patients）and FQs-sensitive group（520 patients）according to their FQs-resistance status. The distribution of total resistance to 13 antituberculosis drugs in 583 patients was analyzed，and the baseline characteristics of patients in the FQs-resistant group and FQs-sensitive group were compared. After screening the characteristic variables using least absolute shrinkage and selection operator（LASSO）regression model，multivariate Logistic regression was performed to analyze the independent risk factors for the resistance of FQs. A Nomogram prediction model was constructed，and its performance was validated by calculating the area under the curve（AUC）of receiver operating characteristic（ROC），and plotting the calibration curve. Results Among 583 patients，520 cases were sensitive to FQs and 63 cases were resistant（resistance rate of 10.81%）. The resistance rate of FQs was secondary to the total resistance rate of first-line antituberculosis drugs，including the isoniazid（36.36%），rifampicin（32.76%），streptomycin（21.61%），and ethambutol（12.86%）. The resistance rates of rifampicin，isoniazid，ethambutol，streptomycin，levofloxacin，moxifloxacin and rifampicin resistance（RR），multidrug resistance（MDR），and pre-XDR were significantly higher in patients of the retreatment group than those of the initial treatment group（P<0.05）. The proportions of patients with ethnic minorities，retreatment，acquired immunodeficiency syndrome（AIDS），history of drug abuse，cavitation，hemoptysis，history of irregular anti-TB and MDR were significantly higher in the FQs-resistance group than those of the FQs-sensitive group（P<0.05）. Through LASSO regression，six variables of ethnicity，treatment history，AIDS，drug abuse history，hemoptysis，and MDR were screened out as influencing factors. Multivariate Logistic regression analysis showed that ethnicity（OR=2.313，95% CI=1.153-4.640，P=0.018），retreatment（OR=1.892，95%CI=1.005-3.560，P=0.048），hemoptysis（OR=1.941，95%CI=1.087-3.465，P=0.025），and MDR（OR=3.342，95% CI=2.398-7.862，P<0.001）were the independent risk factors for FQs resistance in patients with pulmonary tuberculosis. Logistic regression equation Logit（P）=-3.571+0.838×ethnicity+0.638×treatment history+0.663×hemoptysis+1.468×MDR. Based on which a risk Nomogram prediction model was constructed with an AUC of 0.796（95%CI=0.717-0.876）. The Bootstrap method validated the mean absolute error of 0.015，and the predictive model had good calibration ability by the Hosmer-Lemeshow goodness-of-fit test（χ2=3.426，P=0.489）. Conclusion Our findings suggest a high resistant rate of FQs in patients with pulmonary tuberculosis. Ethnic minorities，retreatment，hemoptysis，and MDR are independent risk factors for FQs resistance in patients. The constructed Nomogram prediction model has a good predictive value for FQs resistance in patients with pulmonary tuberculosis. Our study offers new insights into the clinical diagnosis of drug-resistant tuberculosis and the development of rational treatment regimens for RR/MDR-TB.
Subjects: Medicine, Pharmacy >> Clinical Medicine submitted time 2023-12-06 Cooperative journals: 《中国全科医学》
Abstract： Background Aldosterone-producing adenoma（APA） is a common type of primary aldosteronism. For those with unilateral adrenocortical adenoma，although expert consensus recommends plasma aldosterone-to-renin ratio（ARR） as a screening indicator for APA，the range of ARR cut-off values varies widely due to the lack of unified detection method and diagnostic process. Therefore，there is a clinical need for a reliable and rapid predictive model to assist in identifying APA. Objective To explore the correlation between glomerular filtration rate（GFR） and APA，construct and validate the nomogram prediction model of APA. Methods A total of 493 patients with with pathologic results of unilateral adrenal mass who underwent surgical treatment after evaluation of adrenal endocrine hormones in the first affiliated hospital of Shihezi University from 2012 to 2022 were collected，155 patients were ultimately included in the APA group and 113 patients in nonfunctioning adrenal adenoma combined with essential hypertension group according to the diagnostic criteria of APA and nonfunctioning adrenal adenoma. The patients' clinical data and biochemical data were collected. The patients were grouped according to GFR quartiles，and the correlation between GFR and APA was analyzed. The risk factors for APA were screened by multivariate Logistic regression analysis and a nomogram prediction model was constructed. Receiver operating characteristic（ROC） curve was used to analyze the discrimination of the prediction model，a consistency index（C-index） was used to evaluate the predictive accuracy of the model，Hosmer Lemeshow test was used to verify the fit of model，and the diagnostic efficacy of the model was evaluated using decision curve and clinical benefit curve. Results The patients were grouped according to GFR quartiles （Q1 to Q4 groups），Q1 group： ≥ 107.4 ml·min-1·（1.73 m2 ）-1（n=67），Q2 group：99.7-107.3 ml·min-1·（1.73 m2 ）-1 （n=67），Q3 group：88.6-99.6 ml·min-1·（1.73 m2 ）-1（n=67） and Q4 group： ≤ 88.5 ml·min-1·（1.73 m2 ）-1 （n=67），and the proportion of APA in each group was 47.8%（32/67），53.7%（36/67），58.2%（39/67） and 71.6% （48/67）. Logistic regression trend test suggested that the risk of APA tended to increase as GFR levels decreased（P<0.001）. Multivariate Logistic regression analysis showed that systolic blood pressure>160mmHg（OR=5.209，95%CI=2.531-10.720）， hypertension duration ≥ 59 months（OR=4.326，95%CI=1.950-9.595），blood potassium<3.25mmol/L（OR=4.714， 95%CI=2.046-10.860），GFR［Q4 gourp： ≤ 88.5 ml·min-1·（1.73 m2 ）-1］（OR=4.106，95%CI=1.492-11.300）， blood aldosterone>13.42 ng/dL（OR=8.756，95%CI=4.320-17.749） were independent risk factors for the occurrence of APA （P<0.050）. The Nomogram prediction model was constructed based on the above variables of multivariate regression with an AUC of 0.898（95%CI=0.859-0.936） and a C-index of 0.898，indicating a good prediction accuracy. The Hosmer-Lemeshow test showed that the model had a good fit（χ2 =14.059，P=0.080）. The model had a significant predictive efficacy at prediction probability thresholds of 0.10 to 0.90. Conclusion The risk of APA prevalence tends to increase with decreasing GFR levels. The APA prediction model constructed based on five factors，including systolic blood pressure，hypertension course，blood potassium，GFR quartile grouping and plasma aldosterone，has good predictability，consistency and clinical practicality，which can help identify APA and contribute to clinical decision making.
Subjects: Digital Publishing >> New Media submitted time 2023-10-08 Cooperative journals: 《中国传媒科技》
Abstract：随着信息网络技术的不断发展,新媒体得到了快速的发展,短视频逐渐成为人们分享生活的重要平台,促进了信息更加广泛、快速的传播。最开始短视频编辑是以微博平台中的vlog的形式出现的,随着信息技术的发展,专门制作短视频的App也逐渐在网络上兴起,如快手、抖音、火山等平台迅速发展。短视频制作编辑成为当前重要的传播方式之一,人们可以通过短视频分享自己的生活,宣传销售产品等,对社会生活产生了极大的影响。基于此,本文就短视频编辑制作在全媒体编发制作中的重要作用进行分析。
Subjects: Digital Publishing >> New Media submitted time 2023-10-08 Cooperative journals: 《中国传媒科技》
Abstract：近年来,媒体技术发展为我国广播电视行业带来了新的机遇与挑战。一方面,新媒体、新技术的出现为电视节目的制作提供了便利;另一方面,新兴媒体、自媒体的出现与发展使传统广播电视面临观众流失的问题,广播电视行业亟待创新与改革。基于此背景,本文结合实际,就我国广播电视行业的发展现状与未来趋势展开探析,以供参考。
Subjects: Library Science，Information Science >> Library Science submitted time 2023-07-26 Cooperative journals: 《图书情报工作》
Abstract： [Purpose/significance]This article aims to fully grasp the characteristics and development trends of the preservation strategies for university library publishing services in Europe and the United States, and give suggestions to Chinese university libraries on publishing services.[Method/process] Based on the data of Library Publishing Directory (2014-2018) released by the American Library Publishing Coalition, combined with network survey and literature research, the methods of comparative analysis and dialectical analysis are used to study the preservation strategies of publishing services of European and American university libraries in recent years.[Result/conclusion] The results show that, (1)there are a great variety of preservation strategies for publishing services of European and American university libraries, and nearly half of the libraries choose multiple preservation strategies; (2) mainstream preservation strategies have been formed; (3) the preservation strategies of in-house and alliance become important methods; (4) the characteristics of cloud-storage and third-party preservation are obvious. University libraries in China should take full account of the types of documents published, the publishing platforms adopted and the preservation alliances they participate in, when choosing preservation strategies.
Subjects: Geosciences >> Geography submitted time 2020-01-06 Cooperative journals: 《干旱区地理》
Abstract：为分析不同因素对泥石流灾害危险性的影响程度，基于对舟曲南屿沟泥石流灾害影响因素调查结果总结和分析，利用灰色理论分析了泥石流灾害危险性与影响因素间关联程度，并建立了其预判模型。结果表明：沟岸坡度、沟道堵塞程度及冲淤变幅，沟道平均纵坡降和长度，沟道内植被覆盖率、流域面积及人口密度，松散固体物源量和灾害点密度等因素的影响程度较接近；相同区域内不同沟道泥石流灾害危险性程度受沟岸坡度、沟道堵塞程度、冲淤变幅、沟道平均纵坡降及长度等因素影响显著；基于自然和人为因素建立了泥石流灾害易发程度预估模型，其能够为区域内泥流灾害防治工作部署提供依据。
Subjects: Medicine, Pharmacy >> Clinical Medicine submitted time 2019-11-15 Cooperative journals: 《协和医学杂志》
Abstract：患者男性，87岁，主诉“皮疹1月余，胸闷伴少尿11天”，于2019年4月29日收住北京协和医院老年医学科。
Subjects: Astronomy >> Astrophysical processes submitted time 2019-11-13 Cooperative journals: 《天文研究与技术》
Abstract：无线电监测表明，手机与基站通信产生的干扰信号会影响射电天文观测数据，为了抑制射频干扰，天文学家提出屏蔽站内电子设备、设置无线电宁静区等无线电管理办法，其中的手机信号因易移动、基数大而难于监测和管理。然而，开启手机的飞行模式或关机可以降低射频干扰。基于此，本文设计和开发了一款基于Android系统的手机干扰管理APP，采用定位技术来自动判别手机是否处于无线电宁静区，以提醒用户管理手机，并记录用户在宁静区内的操作。测试结果表明，当用户处于无线电宁静区时，APP能主动提醒用户开启飞行模式或关机，有效降低手机信号对天文观测数据的影响。
Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2019-03-05 Cooperative journals: 《电气工程学报》
Abstract：由于 GIS 母线用热补偿型波纹管设计存在的问题，导致变电站运维过程中 不能补偿由于温度变化引起的筒体变形，造成固定支撑产生裂纹或开裂。针对以上问 题，分析 GIS 母线用波纹管变形的主要因素和设计原则，通过电磁场与温度场的耦合 仿真计算，确定 GIS 筒体在额定电流下的温升，为波纹管伸缩量设计提供关键参数， 并通过试验进行验证。试验结果表明：仿真计算结果与温升试验结果一致，能够为波 纹管设计提供可靠的理论依据。
Subjects: Biology >> Bioengineering submitted time 2018-08-29 Cooperative journals: 《中国生物工程杂志》
Abstract：为制备Cancer testis 55（CT55）单克隆抗体，需构建带有人源CT55片段的原核表达质粒，把该质粒转化Rosetta感受态进行原核表达并得到目的蛋白，蛋白被纯化后免疫6w雌性BALB/c小鼠。按传统的单克隆抗体的制备方法，取小鼠脾细胞与骨髓瘤细胞（sp2/0）进行融合，经ELISA方法筛选及两次连续亚克隆，共获得多株能稳定分泌抗 CT55蛋白单克隆抗体的杂交瘤细胞，如3D8B7B12、4C8E1C9、3D8C10G9等。ELISA及Western Blot（WB）分析结果表明，筛选的细胞株均能产生单克隆抗体，且该抗体均分别能与原核表达及真核表达的CT55蛋白发生特异性结合。单克隆抗体可用于免疫荧光试验，且与P53发生互作的荧光主要位于细胞核边缘。结果表明，本研究成功制备了针对人源CT55 蛋白的单克隆抗体。CT55蛋白单克隆抗体的制备为今后肝癌、胃癌、结肠癌等癌症的快速的病原学诊断以及 CT55蛋白的结构和功能研究奠定了物质基础。
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-05-18 Cooperative journals: 《计算机应用研究》
Abstract： Based on the powerful nonlinear mapping ability of kernel learning, proposing a class of kernel learning method for the short-term traffic flow forecasting. Kernel recursive least squares (KRLS) method using Approximate Linear Dependence (ALD) technique can reduce the computational complexity and storage capacity, the KRLS method is an online kernel learning method and is suitable for training on large-scale data sets. Kernel partial least square (KPLS) method utilizes the covariance between input and output variables to extract latent features. Kernel extreme learning machine(KELM) method uses the kernel function to substitute for the unknown nonlinear feature mapping of the hidden layer, in addition, the output weights of the networks can also be analytically determined by using regularization least square algorithm, hence KELM method provides better generalization performance at a much faster learning speed. In order to verify the validity of the proposed kernel learning method, the employed ALD-KRLS, KPLS and KELM methods were respectively applied to different traffic flow forecasting instances in different area, compared to the other methods under the same conditions. Experimental results show that the proposed kernel-based learning methods have higher forecasting accuracy and have improved training speed in the short-term traffic flow forecasting.
Subjects: Materials Science >> Materials Science (General) submitted time 2017-11-21 Cooperative journals: 《金属学报》
Abstract：提出一种可降低铸锭宏观偏析的铸造工艺：层状铸造 (Layer Casting, LC)，将铸锭分为数个甚至数十个浇包逐次间隔浇注，使每包次浇入的金属液依次、逐层凝固，从而达到降低铸锭中宏观偏析的目的。采用实验与数值模拟相结合的手段验证该工艺的可行性和适用性。分别采用传统铸造工艺和层状铸造工艺制备Al-4.0%Cu(质量分数)小铸锭，采用直读光谱仪测量铸锭中心截面处Cu含量并绘制出对应的宏观偏析图。实验结果表明：采用传统铸造工艺制备的铸锭出现明显的宏观偏析，包括铸锭底部严重的负偏析和顶部正偏析；而采用层状铸造工艺制备的铸锭没有出现大范围严重的宏观偏析，铸锭中心线上最小负偏析和最大正偏析分别降低了24.6%和77.2%，说明层状铸造工艺可一定程度改善铸锭宏观偏析。同时，采用柱状晶-等轴晶混合三相凝固模型对100 t钢锭的传统铸造工艺以及层状铸造工艺的宏观偏析的形成进行数值模拟预测。模拟结果表明：采用层状铸造工艺可有效改善大型钢锭中的宏观偏析，并且随着钢锭尺寸的增大，该工艺对宏观偏析的改善效果愈加明显。并对层状铸造工艺在抑制宏观偏析的作用机理进行了分析。
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-10-17 Cooperative journals: 《工程热物理学报》
Abstract：本文数值研究了肋片和凹槽共同作用下矩形通道内的流动与换热特性,分析了肋片高度沿展向的分布情况对通道热力性能的影响。文中选取了五种肋片结构,它们具有不同的高度分布和相同的横截面积,从结构1到结构5,肋片中心高度逐渐增加,其中结构3的肋片具有均匀的高度分布。研究结果表明:高度沿展向分布不均匀的肋片会产生反向旋转的涡对,这些涡对能够卷吸主流中心冷却空气输送到高温壁面,同时吹扫凹槽内的低速热空气,增加凹槽近壁面处的气流速度,从而强化加热面的换热性能;并且,肋片高度沿展向变化越大,旋涡结构越强,强化换热效果越显著;肋片中心高度最高的结构5提供了最大的努塞尔数、摩擦因子以及热力性能因子。
Subjects: Biology >> Bioengineering submitted time 2017-07-24 Cooperative journals: 《中国生物工程杂志》
Abstract： Objective: An IRES-based vector was constructed to achieve co-expression of two target genes with the screening marker gene promoted by the single promoter, and to improve the screening efficiency of multiple genes co-stable expression cell lines. Methods: A bicistronic expression element BamHI-MCS1-IRES-MCS2-IRES-BsiWI which has two multiple cloning sites was designed and synthesized. The vector named pLV-2MCS-Puro was constructed by inserting the element into the skeleton vector pLV-MCS-Puro which was constructed previously in our lab. The DsRed2 and EGFP genes were inserted simultaneously into the vector to test the screening efficiency of multiple genes co-stable expression cell lines. Results: The vector pLV-2MCS-Puro and the recombinant plasmid pLV-DsRed2-EGFP-Puro were constructed successfully. Transient transfection experiment showed that the vector can mediate co-expression of multiple genes. MDCK and Hela cell pools resistant to puromycin were obtained through transfection of the recombinant plasmid. The fluorescent inverted microscope showed that DsRed2 gene at the upstream of the IRES sequence and EGFP gene at the downstream of IRES sequence were co-expressed in cells, and the double positive rate was close to 100%. It indicated that this vector has high screening efficiency. The results of genomic PCR, RT-PCR and Western Blot showed that DsRed2 and EGFP genes were stably integrated into cell genome and the two proteins were expressed consistently. Conclusion: The IRES-based vector pLV-2MCS-Puro was successfully constructed and proved to be efficiently in screening multiple genes co-stable expression cell lines. This vector will have certain application prospects in studying protein interactions and constructing engineering cell lines.
Subjects: Materials Science >> Materials Science (General) submitted time 2017-03-31 Cooperative journals: 《金属学报》
Abstract： 板坯低温加热工艺是国内外生产取向硅钢的先进工艺，而渗氮是通过低温工艺生产取向硅钢的关键工序。本文通过在实验室模拟取向硅钢的渗氮生产工序，实测了不同渗氮时间下的渗氮量，并通过电子探针、场发射扫描电镜等观察了渗氮后氧化层的变化、氮在硅钢带厚度方向的浓度梯度。根据实测的组织形貌和渗氮动力学特点，首次建立了针对取向硅钢的渗氮动力学模型，并成功地进行了数值模拟计算。研究结果表明： (1) 取向硅钢带的平均N含量在渗氮初期增加缓慢，之后逐渐加快，直至90 s时渗氮速率达到最大值之后保持恒定；在750 ℃渗氮2分钟时间内，在近表面0.04 mm范围内存在显著的氮浓度梯度；(2) 脱碳退火后，取向硅钢的氧化层主要为层状氧化物，渗氮时氧化层被氢气还原，层状氧化物转变为球状，氧化层的变化对渗氮动力学影响恒定； (3) 分析了N由气相穿过表面氧化层至铁基体的传质系数所遵循的可能模型，发现只有当传质系数遵循氧化层还原动力学模型时，即Avrami函数模型f=1-exp?(-kt^n)，计算结果才能与实测的渗氮动力学特征高度吻合。
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-03-22 Cooperative journals: 《工程热物理学报》
Abstract：本文采用非线性Darcian多孔介质模型，对三种不同后夹板结构刷式密封的泄漏流动特性进行了数值研究，分析了压比、转速以及后夹板结构形式对刷式密封泄漏量、流场以及压力分布的影响规律。研究结果表明：刷式密封的泄漏量随压比的增大呈线性增大，随转速升高则略微减小。刷式密封的压力下降主要发生在刷丝束内部区域，而在上下游流体域内气流压力则基本分布均匀。后夹板的非通环形槽结构对刷式密封泄漏量及压力分布的影响很小，而通槽结构则会引起泄漏量的大幅增长，同时使压力分布产生变化。
Subjects: Computer Science >> Information Security submitted time 2017-03-10
Abstract：随着信息技术的飞速发展，信息安全问题越来越得到全社会的重视。其中网络内容安全是最突出的问题之一，而作为网络内容安全处理核心技术的网络数据流过滤技术也面临着新的挑战。本文从网络数据流过滤问题出发，研究利用多通道信息进行网络数据流分类的技术，包括以下三方面的工作：（1）多通道 网络流分类模型研究，提出了可融合网络结构信息和网络内容信息的流分类模型；（2）分类模型索引技术 研究，提出一种基于 R-Tree 分类模型索引结构，极大地提高了网络数据流的判别速度；（3）多通道网络流 过滤系统 F9 实验平台建设，该系统支持多通道网络流判别过滤，可作为新模型与算法的实验平台。以上三 方面的工作从模型构造，模型索引，和模型实现三方面系统研究了面向信息过滤的多通道网络流分类系统。
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