试验设计课程教学思考

为提高高等教育教学的质量,需要高等教育课程在教学过程中不断进行改革,紧跟学科发展前沿,与时俱进。针对试验设计课程,本文探讨了如何从采用合适教材、激发学生兴趣手段、培养教师素质、改进教学方法和教学手段等方面提高学生的学习兴趣,加深对理论知识的理解,最终通过多种途径达到掌握这门课程的目标,为今后的学习和工作打下了坚实的基础。

数学建模竞赛对提升研究生创新能力的影响研究

针对研究生教育中的创新能力培养问题,本文分析了近年中国研究生数学建模竞赛的赛题和方法后,指出了数学建模在研究生学习成长中的重要作用,强调了数学建模竞赛能够激发研究生的创新意识,并提出了以数学建模竞赛提升研究生创新思维和实践能力的一些建议。

Optimization of Fermentation Medium for Producing α-Hydroxyphenylacetic Acid by Using Plackett-Burman Design and Response Surface Methodology

Plackett-Burman design and response surface methodology were applied in order to optimize the fermentation medium of (R)-α-hydroxyphenylacetic acid ((R)-HPA) producing Bacillus sp. HZG-19. The factors playing important roles in the production of (R)-HPA were selected based on Plackett-Burman design. The path of steepest ascent was undertaken to optimize said fermentation medium. Finally, the optimal levels of the factors with the greatest change in regard to product yield were further optimized using Box-Behnken and response surface analysis. The optimal conditions were found to be as follows: casein peptone 30.49 (g × L-1), glycerol 14.09 (g × L-1), KH2PO4 0.1345 (g × L-1), K2HPO4 0.01 (g × L-1), CaCl2 0.1 (g × L-1), MnSO4 0.01 (g × L-1). Under the optimal conditions described above, the yield of (R)-HPA reached 63.30%, which indicated an increase of 14.9%, as compared to the yield obtained before optimization.

Diffusion tensor imaging fiber tracking with reliable tracking orientation and flexible step size

We propose a method of reliable tracking orientation and flexible step size fiber tracking. A new directional strategy was defined to select one optimal tracking orientation from each directional set, which was based on the single-tensor model and the two-tensor model. The directional set of planar voxels contained three tracking directions： two from the two-tensor model and one from the single- tensor model. The directional set of linear voxels contained only one principal vector. In addition, a flexible step size, rather than fixable step sizes, was implemented to improve the accuracy of fiber tracking. We used two sets of human data to assess the performance of our method; one was from a healthy volunteer and the other from a patient with low-grade glioma. Results verified that our method was superior to the single-tensor Fiber Assignment by Continuous Tracking and the two-tensor eXtended Streamline Tractography for showing detailed images of fiber bundles.

A New X-band Weather Radar System with Distributed Phased-Array Front-ends: Development and Preliminary Observation Results

A novel weather radar system with distributed phased-array front-ends was developed. The specifications and preliminary data synthesis of this system are presented, which comprises one back-end and three or more front-ends. Each front-end, which utilizes a phased-array digital beamforming technology, sequentially transmits four 22.5°-width beams to cover the 0°–90° elevational scan within about 0.05 s. The azimuthal detection is completed by one mechanical scan of0°–360° azimuths within about 12 s volume-scan update time. In the case of three front-ends, they are deployed according to an acute triangle to form a fine detection area(FDA). Because of the triangular deployment of multiple phased-array front-ends and a unique synchronized azimuthal scanning(SAS) rule, this new radar system is named Array Weather Radar(AWR). The back-end controls the front-ends to scan strictly in accordance with the SAS rule that assures the data time differences(DTD) among the three front-ends are less than 2 s for the same detection point in the FDA. The SAS can maintain DTD < 2 s for an expanded seven-front-end AWR. With the smallest DTD, gridded wind fields are derived from AWR data, by sampling of the interpolated grid, onto a rectangular grid of 100 m ×100 m ×100 m at a 12 s temporal resolution in the FDA. The first X-band single-polarized three-front-end AWR was deployed in field experiments in 2018 at Huanghua International Airport, China. Having completed the data synthesis and processing, the preliminary observation results of the first AWR are described herein.

Fractional Differential Equations with Initial Conditions at Inner Points in Banach Spaces

This paper is concerned with nonlinear fractional differential equations with the Caputo fractional derivatives in Banach spaces. Local existence results are obtained for initial value problems with initial conditions at inner points for the cases that the nonlinear parts are Lipschitz and non-Lipschitz, respectively. Hausdorff measure of non-compactness and Darbo-Sadovskii fixed point theorem are employed to deal with the non-Lipschitz case. The results obtained in this paper extend the classical Peano’s existence theorem for first order differential equations partly to fractional cases.

Exploration of the Teaching of Experimental Design Course

In order to improve the quality of higher education and teaching, higher education courses requires the perpetual reform, which can make the higher education courses follow the frontier development of discipline and keep on the times. Based on using appropriate teaching material, stimulating students’ interest, training the quality of teachers, improving teaching methods, teaching methods and other aspects, this paper proposes some suggestions for experimental design course to improve teaching means and methods, which can enable students to improve the learning interest, deepen the understanding of theoretical knowledge, and through a variety of ways to eventually reach the goal of mastering the course, laid a solid foundation for the future study and work.

Discussion on the Teaching of Experimental Design

Experimental design is mainly about how to reduce the test error caused by interference factors,and how to use the least amount of test data to get comprehensive and reliable test information.It is an important tool course with strong theoretical and practical.Based on the combination of teaching and practice,a targeted selection of teaching content and the use of advanced teaching methods and teaching methods,this paper proposes teaching method to stimulate students interest in learning,deepen the understanding of curriculum content and master and cultivate students’application of the technology in practice activities.

Discussion on the Teaching Concept of Major Production Practice

College students’major production practice is an important part of practical teaching in colleges and universities,a key link of major teaching system,a necessary link of undergraduate teaching training program and teaching plan,and an important form of combining classroom education with social practice.In order to meet the actual needs of college students’major production practice,this paper proposes the key links of establishing strategic cooperation relationship with enterprises and institutions by industry university research channels,ensuring the construction of practice base,changing the ideas of teachers and students,stimulating students’internal motivation,maintaining the goal of professional characteristics,adhering to the exploration of professional characteristics,strengthening the cultivation of comprehensive ability and improving the assessment mechanism of production practice to ensure the high quality of college students’major production practice and achieve the purpose of practice.

Discussion on Cultivation of Collaborative Innovation Ability of Postgraduates Under Background of New Engineering

In view of the increasing number of postgraduates,the quality of postgraduates also presents the situation of multi-level differentiation.In this paper,combined with the requirements of new engineering construction for personnel training,the collaborative innovation training mode of postgraduates under the background of new engineering is explored.Those include:breaking through the single training of teacherpupil inheritance and establishing a team cooperative training mechanism;Breaking through the limit of a single discipline and realizing the cooperative training mechanism of engineering postgraduates across disciplines and schools;Breaking through the closed training in colleges and universities,realizing the cooperative training in the industry,and building a cooperative training mechanism for postgraduates that involves production,study and research;and building an international science and technology cooperation platform and cultivating the cooperative innovation ability of postgraduates.

应用ICP-AES法测定钢砂钢丸的硅、锰、磷含量

应用ICP-AES法测定钢砂、钢丸中的硅、锰、磷元素含量。样品采用稀王水(盐酸+硝酸+水=3+1+8)溶解,在合适的设备参数条件下引入ICP光谱仪,测得的结果与GB/T 223.3~223.5[5][4][3]系列标准测得的结果一致,而本方法更快速、简便。

Analysis of Undergraduate Major Practice Teaching under the Background of New Engineering

Undergraduate major production practice is the key practical teaching link connecting cognition practice and graduation practice,and it is also an important practical teaching process to cultivate college students'quality education and innovative spirit.In order to fully adapt to the training requirements of undergraduate graduates under the background of new engineering and meet the actual needs of current college students,this paper proposes to strengthen the construction of practice base,enhance the supervision construction of professional teachers,increase the diversified collection and strive for professional practice funds,realize the combination of centralized practice and decentralized practice,and standardize the practice management system,so as to ensure the reality of undergraduate specialty learning quality can promote the employment of college students.

船舶材料质量检测可靠性的探讨

船舶材料高新技术发展现状,阐述船舶材料质量检测必要性,例举船舶材料质量检测遇到的问题与解决方案,提出船舶材料质量检测可靠性要求,展望船舶新材料应用及检测技术发展需要。

LNG罐体镍基焊材快速分析技术研究

Ni-Cr-Mo(W合金)或Ni-Cr-Mo-Cu合金的镍基焊材,在硝酸、盐酸、硫酸及高氯酸等强酸介质中能保持较强的抗腐蚀性能。进行镍基焊材定量分析,针对样品消解不完全和多种合金元素试验结果偏差大的问题,通过试验分析,研究样品前处理合适的消解酸配比,设计质量控制方法,解决试验结果偏差大的难题。

Discussion on the Current Training Mode ofFull-time Postgraduate

As an important part of higher education,graduate education is not only an important way to cultivate new scientific research force,but also the only way to produce high-level innovative talents,so it should be highly valued.In order to meet the actual needs of the current full-time postgraduate students,this paper proposes to build a formative evaluation system for graduate students,strengthen interdisciplinary postgraduate training,introduce the concept of total quality management,attach importance to process management,dynamic supervision and tracking,and control the key links in graduate training,so as to ensure the high quality and high suitabilityof graduate training results response.

加权Hardy空间上加权移位算子的约化子空间

本文刻画加权Hardy空间上加权移位算子的约化子空间,讨论多个加权移位算子的公共约化子空间问题,并给出相应算子生成的von Neumann代数的换位代数的结构.作为应用,本文分别刻画双圆盘Bergman空间上一类以拟齐次函数为符号的Toeplitz算子的约化子空间、公共约化子空间及相应的换位代数结构.

^99Tc^m-HYNIC-TOC SPECT/CT显像在胰腺神经内分泌肿瘤患者诊断和随访中的临床应用

目的确定^99Tc^m-联肼尼克酰胺(HYNIC)-酪氨酸3-奥曲肽(TOC)SPECT/CT显像在疑似神经内分泌肿瘤的胰腺肿块评价及胰腺神经内分泌肿瘤患者随访中的价值。方法回顾性分析了184例行^99Tc^m-HYNIC-TOCSPECT/CT显像的患者。所有患者分为2组,组1评价该显像对胰腺可疑肿块的诊断效能(n=140),组2术后随访是否有复发及转移(n=44)。比较注射显像剂后2h的显像结果与最终病理诊断结果及临床随访结果,随后分析肿瘤与本底的比值(TBR)和肿瘤分级的关系。结果组1中,67.9%(95/140)的患者诊断为神经内分泌肿瘤,包括85例神经内分泌瘤和10例神经内分泌癌。^99Tc^m-HYNIC-TOCSPECT/CT显像诊断神经内分泌肿瘤的灵敏度、特异性和准确性分别为81.1%、84.4%和82.1%。

Development and validation of an individualized nomogram for early prediction of the duration of SARS-CoV-2 shedding in COVID-19 patients with non-severe disease

With the number of cases of coronavirus disease-2019(COVID-19)increasing rapidly,the World Health Organization(WHO)has recommended that patients with mild or moderate symptoms could be released from quarantine without nucleic acid retesting,and self-isolate in the community.This may pose a potential virus transmission risk.We aimed to develop a nomogram to predict the duration of viral shedding for individual COVID-19 patients.This retrospective multicentric study enrolled 135 patients as a training cohort and 102 patients as a validation cohort.Significant factors associated with the duration of viral shedding were identified by multivariate Cox modeling in the training cohort and combined to develop a nomogram to predict the probability of viral shedding at 9,13,17,and 21 d after admission.The nomogram was validated in the validation cohort and evaluated by concordance index(C-index),area under the curve(AUC),and calibration curve.A higher absolute lymphocyte count(P=0.001)and lymphocyte-to-monocyte ratio(P=0.013)were correlated with a shorter duration of viral shedding,while a longer activated partial thromboplastin time(P=0.007)prolonged the viral shedding duration.The C-indices of the nomogram were 0.732(95%confidence interval(CI):0.685-0.777)in the training cohort and 0.703(95%CI:0.642-0.764)in the validation cohort.The AUC showed a good discriminative ability(training cohort:0.879,0.762,0.738,and 0.715 for 9,13,17,and 21 d;validation cohort:0.855,0.758,0.728,and 0.706 for 9,13,17,and 21 d),and calibration curves were consistent between outcomes and predictions in both cohorts.A predictive nomogram for viral shedding duration based on three easily accessible factors was developed to help estimate appropriate self-isolation time for patients with mild or moderate symptoms,and to control virus transmission.

Aptamer-based self-assembled supramolecular vesicles for pH-responsive targeted drug delivery

Supramolecular vesicles have received great attention in biomedical application due to their inherent features, including simple synthesis and tunable amphiphilicity of the building blocks. Despite tremendous research efforts, developing supramolecular vesicles with targeted recognition and controlled release remains a major challenge. Herein, we constructed a novel aptamer-based self-assembled supramolecular vesicle by host-guest complexation of pyrene, viologen lipid, and cucurbit[8]urils for pH-responsive and targeted drug delivery. The proposed supramolecular vesicles are easy to be assembled and offer simple drug loading. Based on confocal fluorescence microscopy and cytotoxicity experiments, the drug-loaded supramolecular vesicles were shown to possess highly efficient internalization and apparent cytotoxic effect on target cancer cells, but not control cells.Furthermore, through simple aptamer or drug substitution, supramolecular vesicles can be applied to a variety of target cell lines and drugs, making it widely applicable. Taking advantage of the easy preparation, good stability, rapid pH response, and cell targeting ability, the aptamer-based self-assembled supramolecular vesicles hold great promise in controlled-release biomedical applications and targeted cancer therapy.

Base-controlled annulation of tryptamine-derived isocyanides with nitrile imines for access to polycyclic spiroindoline derivatives

An annulation reaction of tryptamine-derived isocyanides with hydrazonyl chlorides in the presence of bases was developed.Controlled by different bases,[1+2+3]annulation and[1+2+3]/[2+3]annulation cascade were realized.In the latter reaction,five new chemical bonds as well as three new heterocycles were formed in one step.It showed extremely high efficiency,relatively broad substrate scope,milder reaction conditions,good tolerance of functional groups and good chemoselectivity.