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Development of an H reduction and moderate oxidation method for 3,5-dimethylpyridine hydrogenation in trickle bed reactor

《化学科学与工程前沿(英文)》 2022年 第16卷 第12期   页码 1807-1817 doi: 10.1007/s11705-022-2243-2

摘要: The Ru/C catalyst prepared by impregnation method was used for hydrogenation of 3,5-dimethylpyridine in a trickle bed reactor. Under the same reduction conditions (300 °C in H2), the catalytic activity of the non-in-situ reduced Ru/C-n catalyst was higher than that of the in-situ reduced Ru/C-y catalyst. Therefore, an in-situ H2 reduction and moderate oxidation method was developed to increase the catalyst activity. Moreover, the influence of oxidation temperature on the developed method was investigated. The catalysts were characterized by Brunauer–Emmett–Teller method, hydrogen temperature programmed reduction H2-TPR, hydrogen temperature-programmed dispersion (H2-TPD), X-ray diffraction, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, O2 chemisorption and oxygen temperature-programmed dispersion (O2-TPD) analyses. The results showed that there existed an optimal Ru/RuOx ratio for the catalyst, and the highest 3,5-dimethylpyridine conversion was obtained for the Ru/C-i1 catalyst prepared by in-situ H2 reduction and moderate oxidation (oxidized at 100 °C). Excessive oxidation (200 °C) resulted in a significant decrease in the Ru/RuOx ratio of the in-situ H2 reduction and moderate oxidized Ru/C-i2 catalyst, the interaction between RuOx species and the support changed, and the hard-to-reduce RuOx species was formed, leading to a significant decrease in catalyst activity. The developed in-situ H2 reduction and moderate oxidation method eliminated the step of the non-in-situ reduction of catalyst outside the trickle bed reactor.

关键词: Ru/C catalyst     in-situ H2 reduction and moderate oxidation     in-situ reduction     non-in-situ reduction     hydrogenation of 3     5-dimethylpyridine    

A miniature triaxial apparatus for investigating the micromechanics of granular soils with

Zhuang CHENG, Jianfeng WANG, Matthew Richard COOP, Guanlin YE

《结构与土木工程前沿(英文)》 2020年 第14卷 第2期   页码 357-373 doi: 10.1007/s11709-019-0599-2

摘要: The development of a miniature triaxial apparatus is presented. In conjunction with an X-ray micro-tomography (termed as X-ray μCT hereafter) facility and advanced image processing techniques, this apparatus can be used for investigation of the micro-scale mechanical behavior of granular soils under shear. The apparatus allows for triaxial testing of a miniature dry sample with a size of (diameter height). triaxial testing of a 0.4–0.8 mm Leighton Buzzard sand (LBS) under a constant confining pressure of 500 kPa is presented. The evolutions of local porosities (i.e., the porosities of regions associated with individual particles), particle kinematics (i.e., particle translation and particle rotation) of the sample during the shear are quantitatively studied using image processing and analysis techniques. Meanwhile, a novel method is presented to quantify the volumetric strain distribution of the sample based on the results of local porosities and particle tracking. It is found that the sample, with nearly homogenous initial local porosities, starts to exhibit obvious inhomogeneity of local porosities and localization of particle kinematics and volumetric strain around the peak of deviatoric stress. In the post-peak shear stage, large local porosities and volumetric dilation mainly occur in a localized band. The developed triaxial apparatus, in its combined use of X-ray μCT imaging techniques, is a powerful tool to investigate the micro-scale mechanical behavior of granular soils.

关键词: triaxial apparatus     X-ray μCT     in situ test     micro-scale mechanical behavior     granular soils    

Multi-color space threshold segmentation and self-learning <i>ki>-NN algorithm for surge test EUT status

Jian HUANG,Gui-xiong LIU

《机械工程前沿(英文)》 2016年 第11卷 第3期   页码 311-315 doi: 10.1007/s11465-016-0376-z

摘要:

The identification of targets varies in different surge tests. A multi-color space threshold segmentation and self-learning k-nearest neighbor algorithm (k-NN) for equipment under test status identification was proposed after using feature matching to identify equipment status had to train new patterns every time before testing. First, color space (L*a*b*, hue saturation lightness (HSL), hue saturation value (HSV)) to segment was selected according to the high luminance points ratio and white luminance points ratio of the image. Second, the unknown class sample Sr was classified by the k-NN algorithm with training set Tz according to the feature vector, which was formed from number of pixels, eccentricity ratio, compactness ratio, and Euler’s numbers. Last, while the classification confidence coefficient equaled k, made Sr as one sample of pre-training set Tz′. The training set Tz increased to Tz+1 by Tz′ if Tz′ was saturated. In nine series of illuminant, indicator light, screen, and disturbances samples (a total of 21600 frames), the algorithm had a 98.65% identification accuracy, also selected five groups of samples to enlarge the training set from T0 to T5 by itself.

关键词: multi-color space     k-nearest neighbor algorithm (k-NN)     self-learning     surge test    

Potential unreliability of ALK variant allele frequency in the efficacy prediction of targeted therapy in NSCLC

《医学前沿(英文)》 2023年 第17卷 第3期   页码 493-502 doi: 10.1007/s11684-022-0946-x

摘要: Anaplastic lymphoma kinase (ALK) is the most common fusion gene involved in non-small cell lung cancer (NSCLC), and remarkable response has been achieved with the use of ALK tyrosine kinase inhibitors (ALK-TKIs). However, the clinical efficacy is highly variable. Pre-existing intratumoral heterogeneity (ITH) has been proven to contribute to the poor treatment response and the resistance to targeted therapies. In this work, we investigated whether the variant allele frequencies (VAFs) of ALK fusions can help assess ITH and predict targeted therapy efficacy. Through the application of next-generation sequencing (NGS), 7.2% (326/4548) of patients were detected to be ALK positive. On the basis of the adjusted VAF (adjVAF, VAF normalization for tumor purity) of four different threshold values (adjVAF < 50%, 40%, 30%, or 20%), the association of ALK subclonality with crizotinib efficacy was assessed. Nonetheless, no statistical association was observed between median progression-free survival (PFS) and ALK subclonality assessed by adjVAF, and a poor correlation of adjVAF with PFS was found among the 85 patients who received first-line crizotinib. Results suggest that the ALK VAF determined by hybrid capture-based NGS is probably unreliable for ITH assessment and targeted therapy efficacy prediction in NSCLC.

关键词: ALK fusion     next-generation sequencing     fluorescence in situ hybridization     immunohistochemistry     variant allele frequency     intratumoral heterogeneity     targeted therapy    

A review on

Shaolong WAN,Yong WANG

《化学科学与工程前沿(英文)》 2014年 第8卷 第3期   页码 280-294 doi: 10.1007/s11705-014-1436-8

摘要: Catalytic fast pyrolysis (CFP) is deemed as the most promising way to convert biomass to transportation fuels or value added chemicals. Most works in literature so far have focused on the CFP where the catalysts are packed or co-fed with the feedstock in the pyrolysis reactor. However, the CFP with catalysts separated from the pyrolyzer has attracted more and more attentions due to its unique advantages of individually optimizing the pyrolysis conditions and catalyst performances. This review compares the differences between the and CFP operation, and summarizes the development and progress of CFP applications, including the rationale and performances of different catalysts, and the choices of suitable reactor systems. Due to the complex composition of bio-oil, no single approach was believed to be able to solve the problems completely among all those existing technologies. With the increased understanding of catalyst performances and reaction process, the recent trend toward an integration of biomass or bio-oil fractionation with subsequent thermo/bio-chemical conversion routes is also discussed.

关键词: catalytic fast pyrolysis     ex situ     catalysts    

Development of lunar regolith-based composite for - 3D printing via high-pressure extrusion system

《机械工程前沿(英文)》 2023年 第18卷 第2期 doi: 10.1007/s11465-022-0745-8

摘要: To fully utilize the in-situ resources on the moon to facilitate the establishment of a lunar habitat is significant to realize the long-term residence of mankind on the moon and the deep space exploration in the future. Thus, intensive research works have been conducted to develop types of 3D printing approach to adapt to the extreme environment and utilize the lunar regolith for in-situ construction. However, the in-situ 3D printing using raw lunar regolith consumes extremely high energy and time. In this work, we proposed a cost-effective melting extrusion system for lunar regolith-based composite printing, and engineering thermoplastic powders are employed as a bonding agent for lunar regolith composite. The high-performance nylon and lunar regolith are uniformly pre-mixed in powder form with different weight fractions. The high-pressure extrusion system is helpful to enhance the interface affinity of polymer binders with lunar regolith as well as maximize the loading ratio of in-situ resources of lunar regolith. Mechanical properties such as tensile strength, elastic modulus, and Poisson’s ratio of the printed specimens were evaluated systematically. Especially, the impact performance was emphasized to improve the resistance of the meteorite impact on the moon. The maximum tensile strength and impact toughness reach 36.2 MPa and 5.15 kJ/m2, respectively. High-pressure melt extrusion for lunar regolith composite can increase the effective loading fraction up to 80 wt.% and relatively easily adapt to extreme conditions for in-situ manufacturing.

关键词: in-situ resource utilization     melt extrusion molding     lunar regolith-based composites     mechanical properties     additive manufacturing    

基于三维扫描振镜的原位激光加工方法研究 Article

李晓, 刘斌, 梅雪松, 王文君, 王晓东, 李珣

《工程(英文)》 2020年 第6卷 第1期   页码 68-76 doi: 10.1016/j.eng.2019.07.024

摘要:

本文通过研究三维扫描振镜及工业相机耦合构建的三维原位激光加工系统,提出了一种基于线结构光的工件三维扫描测量方式来获取工件三维模型信息的方法。该测量方法创新地将高度标定法用于三维测量精度的提高中,并成功地保证了后续加工时激光在三维工件上的精确聚焦。为了实现便捷高效的激光三维加工,研究人员开发了相关的原位加工软件,并通过实验案例验证了基于三维扫描振镜的原位激光加工方法与实验装置的可行性及实用性。与传统的线结构光测量方法相比,本研究的优点在于提出的方法不需要光平面标定和配置额外的运动轴来实现三维重建,并体现出了较高便捷性及较低成本优势:通过原位的激光加工方式可以实现测量加工一体化,进而降低时间和劳动成本。

关键词: 原位加工     三维扫描振镜     线结构光     激光加工     三维测量    

><i>In situi> growth of phosphorized ZIF-67-derived amorphous CoP/Cu2O@CF electrocatalyst

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1430-1439 doi: 10.1007/s11705-023-2320-1

摘要: Transition metal phosphides have been extensively studied for catalytic applications in water splitting. Herein, we report an in situ phosphorization of zeolitic imidazole frameworks (ZIF-67) to generate amorphous cobalt phosphide/ZIF-67 heterojunction on a self-supporting copper foam (CF) substrate with excellent performance for hydrogen evolution reaction (HER). The needle-leaf like copper hydroxide was anchored on CF surface, which acted as implantation to grow ZIF-67. The intermediate product was phosphorized to obtain final electrocatalyst (CoP/Cu2O@CF) with uniform particle size, exhibiting a rhombic dodecahedron structure with wrinkles on the surface. The electrochemical measurement proved that CoP/Cu2O@CF catalyst exhibited excellent HER activity and long-term stability in 1.0 mol·L–1 KOH solution. The overpotential was only 62 mV with the Tafel slope of 83 mV·dec–1 at a current density of 10 mA·cm–2, with a large electrochemical active surface area. It also showed competitive performance at large current which indicated the potential application to industrial water electrolysis to produce hydrogen. First-principle calculations illustrated that benefit from the construction of CoP/ZIF-67 heterojunction, the d-band center of CoP downshifted after bonding with ZIF-67 and the Gibbs free energy (ΔGH*) changed from –0.18 to –0.11 eV, confirming both decrease in overpotential and excellent HER activity. This work illustrates the efficient HER activity of CoP/Cu2O@CF catalyst, which will act as a potential candidate for precious metal electrocatalysts.

关键词: CoP/Cu2O@CF     electrocatalyst     phosphorization     HER     DFT    

基于荧光原位杂交技术的UASB颗粒污泥中苯酚降解微生物生态位分化研究 Article

Kengo Kubota, Kei Igarashi, Masayoshi Yamada, Yasuyuki Takemura, Yu-You Li, Hideki Harada

《工程(英文)》 2022年 第9卷 第2期   页码 61-66 doi: 10.1016/j.eng.2021.05.012

摘要:

利用荧光原位杂交(FISH)和克隆文库构建技术,研究了厌氧污泥床反应器处理含酚废水时所收获的颗粒的微生物群落结构。研究发现,互营杆菌(Syntrophorhabdaceae)和隐杆厌氧菌(Cryptanaerobacter)的克隆是苯酚降解的主要原因。为了准确地对隐杆厌氧菌的克隆进行分类归属,需要利用近全长的16S核糖体RNA(rRNA)基因序列进行进化分析。设计了三种寡核苷酸探针用于检测以下三个分类群:互营杆菌、隐杆厌氧菌和互养菌。对厌氧颗粒薄片的FISH 分析显示细菌和古菌呈随机分布。然而,互营杆菌、隐杆厌氧菌和互养菌分布明确。在颗粒细胞的外层发现了隐杆厌氧菌和互养菌,两者关系密切,而互营杆菌则位于颗粒细胞的深层。细菌之间的代谢联系和对底物的亲和力很可能是造成这种特殊分布的原因。研究人员观察到颗粒污泥中苯酚的降解主要通过以下方式进行:首先,隐杆厌氧菌将苯酚转化为苯甲酸盐,然后被互养菌降解为乙酸盐。苯酚的这种互饲降解发生在颗粒表面附近,此处苯酚浓度较高。在苯酚浓度较低的颗粒深部,互营杆菌将苯酚降解为乙酸盐。结果表明,互营杆菌不太可能产生苯甲酸盐,并将其作为中间产物来喂养邻近的生物,这一点与以往研究所提出的理论相矛盾。

关键词: 隐杆厌氧菌(<i>Cryptanaerobacteri>)     荧光原位杂交     苯酚厌氧降解     互营杆菌(Syntrophorhabdaceae)     互养菌(<i>Syntrophusi>)    

Development of lunar regolith composite and structure via laser-assisted sintering

《机械工程前沿(英文)》 doi: 10.1007/s11465-021-0662-2

摘要: Aiming at the exploration and resource utilization activities on the Moon, in situ resource utilization and in situ manufacturing are proposed to minimize the dependence on the ground transportation supplies. In this paper, a laser-assisted additive manufacturing process is developed to fabricate lunar regolith composites with PA12/SiO2 mixing powders. The process parameters and composite material compositions are optimized in an appropriate range through orthogonal experiments to establish the relationship of process–structure–property for lunar regolith composites. The optimal combination of composite material compositions and process parameters are mixing ratio of 50/50 in volume, laser power of 30 W, scanning speed of 3500 mm/s, and scanning hatch space of 0.2 mm. The maximum tensile strength of lunar regolith composites reaches 9.248 MPa, and the maximum depth of surface variation is 120.79 μm, which indicates poor powder fusion and sintering quality. Thereafter, the mechanical properties of laser-sintered lunar regolith composites are implemented to the topology optimization design of complex structures. The effectiveness and the feasibility of this laser-assisted process are potentially developed for future lightweight design and manufacturing of the solar panel installed on the lunar rover.

关键词: in situ manufacturing     laser-assisted powder fusion process     mechanical properties     topological structure design    

CeO doping boosted low-temperature NH-SCR activity of FeTiO catalyst: A microstructure analysis and reaction mechanistic study

《环境科学与工程前沿(英文)》 2022年 第16卷 第5期 doi: 10.1007/s11783-022-1539-2

摘要:

• CeO2 doping significantly improved low-temperature NH3-SCR activity on FeTiOx.

关键词: NH3-SCR     CeO2 doping     Low-temperature NOx removal     Improved redox property     In situ XAFS analysis    

density measurement for plastic injection molding via ultrasonic technology

《机械工程前沿(英文)》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0714-2

摘要: Density variation during the injection molding process directly reflects the state of plastic melt and contains valuable information for process monitoring and optimization. Therefore, in-situ density measurement is of great interest and has significant application value. The existing methods, such as pressure−volume−temperature (PVT) method, have the shortages of time-delay and high cost of sensors. This study is the first to propose an in-situ density measurement method using ultrasonic technology. The analyses of the time-domain and frequency-domain signals are combined in the proposed method. The ultrasonic velocity is obtained from the time-domain signals, and the acoustic impedance is computed through a full-spectral analysis of the frequency-domain signals. Experiments with different process conditions are conducted, including different melt temperature, injection speed, material, and mold structure. Results show that the proposed method has good agreement with the PVT method. The proposed method has the advantages of in-situ measurement, non-destructive, high accuracy, low cost, and is of great application value for the injection molding industry.

关键词: ultrasonic measurement     melt density     in-situ measurement     injection molding    

hydrophobic environment triggering reactive fluorescence probe to real-time monitor mitochondrial DNA damage

《化学科学与工程前沿(英文)》 2022年 第16卷 第1期   页码 92-102 doi: 10.1007/s11705-021-2063-9

摘要: Mitochondrial DNA has a special structure that is prone to damage resulting in many serious diseases, such as genetic diseases and cancers. Therefore, the rapid and specific monitoring of mitochondrial DNA damage is urgently needed for biological recognition. Herein, we constructed an in situ hydrophobic environment-triggering reactive fluorescence probe named MBI-CN. The fluorophore was 2-styrene-1H-benzo[d]imidazole, and malononitrile was introduced as a core into a molecule to initiate the hydrolysis reaction in the specific environment containing damaged mitochondrial DNA. In this design, MBI-CN conjugates to mitochondrial DNA without causing additional damages. Thus, MBI-CN can be hydrolyzed to generate MBI-CHO in an in situ hydrophobic environment with mitochondrial DNA damage. Meanwhile, MBI-CHO immediately emitted a significative fluorescence signal changes at 437 and 553 nm within 25 s for the damaged mitochondria DNA. Give that the specific and rapid response of MBI-CN does not cause additional damages to mitochondrial DNA, it is a potentially effective detection tool for the real-time monitoring of mitochondrial DNA damage during cell apoptosis and initial assessment of cell apoptosis.

关键词: hydrolysis reaction     mitochondrial DNA damage     in situ hydrophobic environment trigger     fluorescence probe     apoptosis    

Comprehensive kinetostatic modeling and morphology characterization of cable-driven continuum robots for aero-engine maintenance

《机械工程前沿(英文)》 2023年 第18卷 第3期 doi: 10.1007/s11465-023-0756-0

摘要: In-situ maintenance is of great significance for improving the efficiency and ensuring the safety of aero-engines. The cable-driven continuum robot (CDCR) with twin-pivot compliant mechanisms, which is enabled with flexible deformation capability and confined space accessibility, has emerged as a novel tool that aims to promote the development of intelligence and efficiency for in-situ aero-engine maintenance. The high-fidelity model that describes the kinematic and morphology of CDCR lays the foundation for the accurate operation and control for in-situ maintenance. However, this model was not well addressed in previous literature. In this study, a general kinetostatic modeling and morphology characterization methodology that comprehensively contains the effects of cable-hole friction, gravity, and payloads is proposed for the CDCR with twin-pivot compliant mechanisms. First, a novel cable-hole friction model with the variable friction coefficient and adaptive friction direction criterion is proposed through structure optimization and kinematic parameter analysis. Second, the cable-hole friction, all-component gravities, deflection-induced center-of-gravity shift of compliant joints, and payloads are all considered to deduce a comprehensive kinetostatic model enabled with the capacity of accurate morphology characterization for CDCR. Finally, a compact continuum robot system is integrated to experimentally validate the proposed kinetostatic model and the concept of in-situ aero-engine maintenance. Results indicate that the proposed model precisely predicts the morphology of CDCR and outperforms conventional models. The compact continuum robot system could be considered a novel solution to perform in-situ maintenance tasks of aero-engines in an invasive manner.

关键词: kinetostatic modeling     morphology characterization     variable friction     continuum robots     in-situ maintenance    

New perspectives in free nitrous acid (FNA) uses for sustainable wastewater management

《环境科学与工程前沿(英文)》 2023年 第18卷 第2期 doi: 10.1007/s11783-024-1786-5

摘要:

● The historical development of free nitrous acid (FNA) technologies is reviewed.

关键词: Free nitrous acid     Acid-tolerant ammonia oxidizer     In situ generation     Wastewater management    

标题 作者 时间 类型 操作

Development of an H reduction and moderate oxidation method for 3,5-dimethylpyridine hydrogenation in trickle bed reactor

期刊论文

A miniature triaxial apparatus for investigating the micromechanics of granular soils with

Zhuang CHENG, Jianfeng WANG, Matthew Richard COOP, Guanlin YE

期刊论文

Multi-color space threshold segmentation and self-learning <i>ki>-NN algorithm for surge test EUT status

Jian HUANG,Gui-xiong LIU

期刊论文

Potential unreliability of ALK variant allele frequency in the efficacy prediction of targeted therapy in NSCLC

期刊论文

A review on

Shaolong WAN,Yong WANG

期刊论文

Development of lunar regolith-based composite for - 3D printing via high-pressure extrusion system

期刊论文

基于三维扫描振镜的原位激光加工方法研究

李晓, 刘斌, 梅雪松, 王文君, 王晓东, 李珣

期刊论文

><i>In situi> growth of phosphorized ZIF-67-derived amorphous CoP/Cu2O@CF electrocatalyst

期刊论文

基于荧光原位杂交技术的UASB颗粒污泥中苯酚降解微生物生态位分化研究

Kengo Kubota, Kei Igarashi, Masayoshi Yamada, Yasuyuki Takemura, Yu-You Li, Hideki Harada

期刊论文

Development of lunar regolith composite and structure via laser-assisted sintering

期刊论文

CeO doping boosted low-temperature NH-SCR activity of FeTiO catalyst: A microstructure analysis and reaction mechanistic study

期刊论文

density measurement for plastic injection molding via ultrasonic technology

期刊论文

hydrophobic environment triggering reactive fluorescence probe to real-time monitor mitochondrial DNA damage

期刊论文

Comprehensive kinetostatic modeling and morphology characterization of cable-driven continuum robots for aero-engine maintenance

期刊论文

New perspectives in free nitrous acid (FNA) uses for sustainable wastewater management

期刊论文