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现代农业双优工程试验原理与方法——以毛乌素沙地为例

王永生,李玉恒,刘彦随

《中国工程科学》 2019年 第21卷 第2期   页码 48-54 doi: 10.15302/J-SSCAE-2019.02.017

摘要:

土地是人类赖以生存与发展的重要资源和物质基础,现代农业的发展依赖于健康、生态、高效的土地。消除退化土地的利用障碍,改良作物生长环境,为不同作物生长需求提供最适宜的“土地配方”,是当前面临的主要问题。针对毛乌素沙地区(榆林)沙化土地整治与可持续利用问题,利用红黏土、黄土与沙土的物理互补性,对沙化土地进行结构性整治,构建沙化土地整治土体优配和现代农业良种优选的复合技术体系,实现“沙化土地的订单式整治”,为毛乌素沙地区(榆林)退化土地整治与现代农业的耦合发展提供科技支撑。未来应重点加强土地工程链研究,创建全链式土地工程管理机制,实现微观土地复配、中观土体营造和宏观土质改良工程的技术化和标准化。

关键词: 土地整治工程     现代农业     土体重构     作物优选     毛乌素沙地    

Shape/size controlling syntheses, properties and applications of two-dimensional noble metal nanocrystals

Baozhen An,Mingjie Li,Jialin Wang,Chaoxu Li

《化学科学与工程前沿(英文)》 2016年 第10卷 第3期   页码 360-382 doi: 10.1007/s11705-016-1576-0

摘要: Two dimensional (2D) nanocrystals of noble metals (e.g., Au, Ag, Pt) often have unique structural and environmental properties which make them useful for applications in electronics, optics, sensors and biomedicines. In recent years, there has been a focus on discovering the fundamental mechanisms which govern the synthesis of the diverse geometries of these 2D metal nanocrystals (e.g., shapes, thickness, and lateral sizes). This has resulted in being able to better control the properties of these 2D structures for specific applications. In this review, a brief historical survey of the intrinsic anisotropic properties and quantum size effects of 2D noble metal nanocrystals is given and then a summary of synthetic approaches to control their shapes and sizes is presented. The unique properties and fascinating applications of these nanocrystals are also discussed.

关键词: two-dimension     noble metal     nanocrystal     surface plasmon     controllable synthesis    

Optimal slot dimension for skirt support structure of coke drums

Edward WANG, Zihui XIA

《机械工程前沿(英文)》 2018年 第13卷 第4期   页码 554-562 doi: 10.1007/s11465-018-0513-y

摘要:

The skirt-to-shell junction weld on coke drums is susceptible to fatigue failure due to severe thermal cyclic stresses. One method to decrease junction stress is to add slots near the top of the skirt, thereby reducing the local stiffness close to the weld. The most common skirt slot design is thin relative to its circumferential spacing. A new slot design, which is significantly wider, is proposed. In this study, thermal-mechanical elastoplastic 3-D finite element models of coke drums are created to analyze the effect of different skirt designs on the stress/strain field near the shell-to-skirt junction weld, as well as any other critical stress locations in the overall skirt design. The results confirm that the inclusion of the conventional slot design effectively reduces stress in the junction weld. However, it has also been found that the critical stress location migrates from the shell-to-skirt junction weld to the slot ends. A method is used to estimate the fatigue life near the critical areas of each skirt slot design. It is found that wider skirt slots provide a significant improvement on fatigue life in the weld and slot area.

关键词: coke drum     stress analysis     cyclic stress     fatigue life     skirt slots    

Immunometabolism: a new dimension in immunotherapy resistance

《医学前沿(英文)》 2023年 第17卷 第4期   页码 585-616 doi: 10.1007/s11684-023-1012-z

摘要: Immune checkpoint inhibitors (ICIs) have demonstrated unparalleled clinical responses and revolutionized the paradigm of tumor treatment, while substantial patients remain unresponsive or develop resistance to ICIs as a single agent, which is traceable to cellular metabolic dysfunction. Although dysregulated metabolism has long been adjudged as a hallmark of tumor, it is now increasingly accepted that metabolic reprogramming is not exclusive to tumor cells but is also characteristic of immunocytes. Correspondingly, people used to pay more attention to the effect of tumor cell metabolism on immunocytes, but in practice immunocytes interact intimately with their own metabolic function in a way that has never been realized before during their activation and differentiation, which opens up a whole new frontier called immunometabolism. The metabolic intervention for tumor-infiltrating immunocytes could offer fresh opportunities to break the resistance and ameliorate existing ICI immunotherapy, whose crux might be to ascertain synergistic combinations of metabolic intervention with ICIs to reap synergic benefits and facilitate an adjusted anti-tumor immune response. Herein, we elaborate potential mechanisms underlying immunotherapy resistance from a novel dimension of metabolic reprogramming in diverse tumor-infiltrating immunocytes, and related metabolic intervention in the hope of offering a reference for targeting metabolic vulnerabilities to circumvent immunotherapeutic resistance.

关键词: immune cell     immunometabolism     metabolic reprogramming     immunotherapy     resistance     tumor microenvironment     immune checkpoint inhibitor    

Diagnosis method based on wavelet coefficient scale relativity correlation dimension for fault

GU Junjie, TIAN Jin, PENG Xuezhi

《能源前沿(英文)》 2008年 第2卷 第2期   页码 164-168 doi: 10.1007/s11708-008-0031-4

摘要: Correlation dimension as a tool to describe machinery condition is introduced. Vibration signals of the fan under different working conditions are analyzed using a threshold filtering algorithm based on the region relativity of the wavelet coefficients for reducing noise. The result shows that the characteristics of the signal could be preserved completely. The correlation dimension is able to identify conditions of the fan with faults compared with the normal condition, thereby providing an effective technology for condition monitoring and fault diagnosis of mechanical equipment.

关键词: effective technology     monitoring     mechanical equipment     relativity     Correlation    

Structural dimension optimization and mechanical response analysis of fabricated honeycomb plastic pavement

Zixuan CHEN; Tao LIU; Xiao MA; Hanyu TANG; Jianyou HUANG; Jianzhong PEI

《结构与土木工程前沿(英文)》 2022年 第16卷 第7期   页码 896-908 doi: 10.1007/s11709-022-0856-7

摘要: Because of favorable mechanical properties, deformation resistance and being conducive to environmental protection, honeycomb fabricated plastic pavement slabs are highly recommended these years. At present, most studies focus on the performance of plastic materials, however, the dimension optimization of fabricated plastic pavement slab is rarely mentioned. In this paper, an optimized geometry of the honeycomb pavement slab was determined through finite element analysis. Mechanical response of honeycomb slabs with different internal dimensions and external dimensions were explored. Several dimension factors were taken into consideration including the side length, rib thickness, the thickness of both top and bottom slabs of honeycomb structure and the length, the width and the thickness of the fabricated plastic slab. The results showed that honeycomb pavement slab with 6 cm bottom slab, 12 cm top slab,18 cm side length and 6 cm rib thickness is recommended, additionally, an external dimension of 4 m × 4 m × 0.45 m is suggested. Then, the mechanical responses of this optimized fabricated plastic slab were further investigated. Significance of different influencing factors, including wheel load, elastic modulus of plastic material, base layer thickness, soil foundation modulus and base layer modulus were ranked.

关键词: honeycomb structure     plastic pavement     dimension optimization     mechanical response     factor significance    

PD pattern recognition based on multi-fractal dimension in GIS

ZHANG Xiaoxing, YAO Yao, TANG Ju, ZHOU Qian, XU Zhongrong

《机械工程前沿(英文)》 2008年 第3卷 第3期   页码 270-275 doi: 10.1007/s11465-008-0042-1

摘要: This paper designs four types of gas insulated substation (GIS) defect models based on partial discharge (PD) characteristics and its defections. The GIS gray intensity images are constructed based on the mass specimens gathered by the ultra-high frequency and high-speed sampling systems. The multi-fractal dimension is founded on the box-counting dimension and multi-fractal theories. The GIS gray intensity images distillation methods, based on multi-fractal characteristics, is put forward. The box-counting dimension, multi-fractal dimension, and discharge centrobaric characteristics of the PD images are also extracted. The characteristic variables are then classified by the radial basis function (RBF) network. Identified results show that the methods can effectively elevate the discrimination of the four types of defects in GIS.

关键词: substation     high-speed     discharge centrobaric     network     ultra-high frequency    

基于RAMI 4.0解读新一代智能制造

赵敏

《中国工程科学》 2018年 第20卷 第4期   页码 90-96 doi: 10.15302/J-SSCAE-2018.04.015

摘要:

为了深入认识中国工程院“基于新一代人工智能的‘中国智能制造发展战略研究报告’”的重要意义,笔者采取了解构和重构的方法,对德国工业4.0参考架构模型(RAMI 4.0)进行了剖析,并与中国工程院报告中提出的智能制造总体架构做了对比,发现了彼此的相同和差异之处,认为中国版智能制造总体架构在智能程度上更胜一筹,这是中国人对智能制造发展的贡献。同时该分析过程亦加深了对二者的认识。

关键词: RAMI 4.0     信息物理系统(CPS)     基本范式     新一代人工智能     架构     技术维     组织维     价值维    

Temporal dimension and water quality control in an emission trading scheme based on water environmental

Zhaoxing HAN, Zhenyao SHEN, Yongwei GONG, Qian HONG

《环境科学与工程前沿(英文)》 2011年 第5卷 第1期   页码 119-129 doi: 10.1007/s11783-011-0272-z

摘要: Emission trading is one of the most effective alternatives to controlling water pollution. Water environmental functional zone (WEFZ) is used to determine the water quality standard and identify the zone boundary for each river or reach. In this study, a new emission trading scheme was addressed based on WEFZ, accounting for both the temporal dimension and water quality control. A temporal factor of emission trading was proposed based on variations in the environmental capacity within a year by dividing the year into three periods, including high, normal, and low periods of environmental capacity. During each period, emission trading was implemented exclusively. A water quality-control scheme was suggested based on the water quality requirement in the water functional zone, in which the water quality at the downstream boundary of the zone was required to meet the water standard following auto-purification in the stream. Two methods of calculating water quality control are addressed for point-source pollution and non-point-source pollution. The calculated temporal dimension and water quality control were located in Dongxi River of the Daning Watershed in the Three Gorges Watershed. The high period was during June, July, and August, the normal period was during April, May, September, and October, and the low period was during January, February, March, November, and December. The results from the water quality calculation demonstrated that the discharge of point-source and non-point-source pollutions led to an excess of common contaminants at the downstream boundary of WEFZ. The temporal and spatial factors above should be incorporated into the emission trading scheme based on WEFZ.

关键词: emission trading     water functional zone     water quality control    

Design and analysis of a class of redundant collaborative manipulators with 2-dimension large rotational

Xiaodong JIN, Yuefa FANG, Dan ZHANG, Xueling LUO

《机械工程前沿(英文)》 2020年 第15卷 第1期   页码 66-80 doi: 10.1007/s11465-019-0570-x

摘要: The parallel spindle heads with high rotational capability are demanded in the area of multi-axis machine tools and 3D printers. This paper focuses on designing a class of 2R1T (R: Rotation; T: Translation) parallel spindle heads and the corresponding collaborative 5-axis manipulators with 2-dimension (2D) large rotational angles. In order to construct 2D rotational degrees of freedom (DOF), a platform with 2-dimension revolute joints is proposed first. Based on the constraint screw theory, the feasible limbs that can be connected in the platform are synthesized. In order to provide constant rotational axis for the platform, a class of redundant limbs are designed. A class of redundant 2R1T parallel spindle heads is obtained by connecting the redundant limbs with the platform and the redundant characteristics are verified by the modified Grübler-Kutzbach criterion. The corresponding 5-axis collaborative manipulators are presented by constructing a 2-DOF series translational bottom moving platform. The inverse kinematics and the orientation workspace as well as the decoupling characteristics of this type of 2R1T parallel spindle heads are analyzed. The results show that these manipulators have large 2D rotational angles than the traditional A3/Z3 heads and can be potentially used in the application of multi-axis machine tools and the 3D printers.

关键词: parallel mechanism     redundant mechanism     large rotational angles     machine tools     2R1T spindle head     collaborative manipulator    

舰船修理文件编制六维度管理方法研究

陈志敏,阳斌

《中国工程科学》 2015年 第17卷 第5期   页码 83-89

摘要:

针对舰船基地级修理文件编制规律与技术特点,提出了成系统、科学的基地级修理文件编制六维度管理方法。在分析舰船装备基地级修理文件国外编制现状的基础上,针对修理文件编制难度大、内容多、涉及外协单位多、质量和进度管理难度大的特点,梳理出基地级修理文件体系,提出了从要求、样例、维修分析、知识库、质量管理、进度管理六个维度对修理文件编制的质量和进度进行管理的创新方法,从工程可操作性上对修理文件的编制管理方法进行了阐述,其研究成果对落实舰船装备基地级修理文件编制工作具有重要意义。

关键词: 舰船;修理文件;六维度管理方法;维修分析    

零件加工质量(尺寸和表面粗糙度)在线检测技术研究

陈爱弟,王信义

《中国工程科学》 2000年 第2卷 第12期   页码 73-77

摘要:

文章研究零件加工质量在线检测的方法和关键技术。在分析在线检测工件尺寸和表面粗糙度检测方法及特点的基础上,建立检测工件尺寸的神经网络和检测表面粗糙度的模糊神经网络,并且建立了零件加工质量在线检测系统。实验表明该方法能够正确地实时检测工件的尺寸变化和工件表面粗糙度。

关键词: 在线检测     神经网络     模糊神经网络     尺寸精度     表面粗糙度    

Carbon dots-based fluorescence sensor for two-photon imaging of pH in diabetic mice

《化学科学与工程前沿(英文)》 2023年 第17卷 第3期   页码 298-306 doi: 10.1007/s11705-022-2212-9

摘要: Herein, a reversible pH fluorescent sensor was developed using caffeic acid as the precursor by one-step solvothermal synthesis method. The carbon dots-based sensor (CA-CDs) exhibited pH-dependent increase in fluorescence intensity and showed linear relationship in the range of pH 6.60 and 8.00. Notably, the fluorescence sensor has a reversible response to pH change. Finally, the CA-CDs has been successfully applied for two-photon imaging of the pH in liver and kidney of diabetic mice. Imaging results showed that the pH value in kidney of diabetic mice was lower than that of the normal mice, while the pH value in liver of diabetic mice was almost the same as that of the normal mice. The present study provides a simple analytical method for pH detection suitable for in vivo.

关键词: carbon dots     two-photon imaging     pH     diabetic mice    

全维可定义的天地协同组网架构与切片技术研究

李丹,朱棣,申涓

《中国工程科学》 2021年 第23卷 第2期   页码 30-38 doi: 10.15302/J-SSCAE-2021.02.005

摘要:

面对未来网络对全维度空间泛在互联互通的信息服务需求,现有的卫星互联网基础架构及由此构建的技术体系在异构协同、资源高效、精准按需、稳定可靠等方面仍面临重大挑战。本文首先对我国卫星互联网技术发展需求进行分析研判,讨论了全球卫星互联网技术的发展现状和趋势;其次阐述了代表性的天地协同广域通信网络组网架构、全维可定义的网络节点;最后从网络智能切片、数据解析与转发、资源协调控制机制等方面,提出天地协同网络中面向业务特性的智能切片关键技术。研究建议:依托天地协同网络架构,以网络资源管理控制、网络智慧化、网络结构全维可定义等技术为支撑,突破业务所需的天地协同网络资源智能切片、全维可定义的数据报文灵活解析与转发、天地协同网络资源全局协调控制等关键技术;在国家层面加大对天地协同网络的政策支持力度,为天地协同网络资源全局动态优化技术创新和产业发展提供持续推动力。

关键词: 天地协同网络,智能网络切片,全维可定义,组网架构与机制    

New medical risks affecting obstetrics after implementation of the two-child policy in China

null

《医学前沿(英文)》 2017年 第11卷 第4期   页码 570-575 doi: 10.1007/s11684-017-0552-5

摘要:

China recently instituted a two-child policy in response to its aging population, declining workforce and demographic dividend, and the need to develop asocial economy. Additionally, women generally delay having a second child because of the overwhelming pressure in their lives. With the improvements in assisted fertility technologies in recent years, the number of elderly women attempting to bear children has increased. The quality of woman’s eggs and a man’s sperm declined dramatically with increasing age, leading to an increased risk of pregnancy-related complications among older women. Therefore, the types of fertility problems experienced by elderly females must be provided with considerable attention by obstetricians. This commentary article focuses on the medical problems faced by older second-child pregnant women. This work discusses their increased rates of infertility, spontaneous abortion, fetal malformation, gestational diabetes, cesarean section, placenta previa, postpartum hemorrhage, postpartum depression, and hypertensive disorders, which complicate pregnancy.

关键词: two-child policy     birth defects     cesarean delivery     placenta previa    

标题 作者 时间 类型 操作

现代农业双优工程试验原理与方法——以毛乌素沙地为例

王永生,李玉恒,刘彦随

期刊论文

Shape/size controlling syntheses, properties and applications of two-dimensional noble metal nanocrystals

Baozhen An,Mingjie Li,Jialin Wang,Chaoxu Li

期刊论文

Optimal slot dimension for skirt support structure of coke drums

Edward WANG, Zihui XIA

期刊论文

Immunometabolism: a new dimension in immunotherapy resistance

期刊论文

Diagnosis method based on wavelet coefficient scale relativity correlation dimension for fault

GU Junjie, TIAN Jin, PENG Xuezhi

期刊论文

Structural dimension optimization and mechanical response analysis of fabricated honeycomb plastic pavement

Zixuan CHEN; Tao LIU; Xiao MA; Hanyu TANG; Jianyou HUANG; Jianzhong PEI

期刊论文

PD pattern recognition based on multi-fractal dimension in GIS

ZHANG Xiaoxing, YAO Yao, TANG Ju, ZHOU Qian, XU Zhongrong

期刊论文

基于RAMI 4.0解读新一代智能制造

赵敏

期刊论文

Temporal dimension and water quality control in an emission trading scheme based on water environmental

Zhaoxing HAN, Zhenyao SHEN, Yongwei GONG, Qian HONG

期刊论文

Design and analysis of a class of redundant collaborative manipulators with 2-dimension large rotational

Xiaodong JIN, Yuefa FANG, Dan ZHANG, Xueling LUO

期刊论文

舰船修理文件编制六维度管理方法研究

陈志敏,阳斌

期刊论文

零件加工质量(尺寸和表面粗糙度)在线检测技术研究

陈爱弟,王信义

期刊论文

Carbon dots-based fluorescence sensor for two-photon imaging of pH in diabetic mice

期刊论文

全维可定义的天地协同组网架构与切片技术研究

李丹,朱棣,申涓

期刊论文

New medical risks affecting obstetrics after implementation of the two-child policy in China

null

期刊论文