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NO oxidation over Co-La catalysts and NO

Tiejun Zhang,Jian Li,Hong He,Qianqian Song,Quanming Liang

《环境科学与工程前沿(英文)》 2017年 第11卷 第2期 doi: 10.1007/s11783-017-0906-x

摘要: The Co-La catalyst (pH= 1) exhibited maximum NO conversion of 43% at 180°C. Acid modified catalyst enhanced the resistance to SO . The formed sulfates may block the pore structure of the catalyst. The NO conversion of compact SCR was 91% at 180°C at the highest space velocity. A series of Co-La catalysts were prepared using the wet impregnation method and the synthesis of catalysts were modified by controlling pH with the addition of ammonium hydroxide or oxalic solution. All the catalysts were systematically investigated for NO oxidation and SO resistance in a fixed bed reactor and were characterized by Brunanuer–Emmett–Teller (BET) method, Fourier Transform infrared spectroscopy (FTIR), X–ray diffraction (XRD), Thermogravimetric (TG) and Ion Chromatography (IC). Among the catalysts, the one synthesized at pH= 1 exhibited the maximum NO conversion of 43% at 180°C. The activity of the catalyst was significantly suppressed by the existence of SO (300 ppm) at 220°C. Deactivation may have been associated with the generation of cobalt sulfate, and the SO adsorption quantity of the catalyst might also have effected sulfur resistance. In the case of the compact selective catalytic reduction (SCR), the activity increased from 74% to 91% at the highest gas hourly space velocity (GHSV) of 300000 h when the NO catalyst maintained the highest activity, in excess of 50% more than that of the standard SCR.

关键词: NO catalytic oxidation     pH effect     Low temperature     Sulfur dioxide     High space velocity     SCR    

High velocity impact of metal sphere on thin metallic plate using smooth particle hydrodynamics (SPH)

Hossein ASADI KALAMEH, Arash KARAMALI, Cosmin ANITESCU, Timon RABCZUK

《结构与土木工程前沿(英文)》 2012年 第6卷 第2期   页码 101-110 doi: 10.1007/s11709-012-0160-z

摘要: The modeling of high velocity impact is an important topic in impact engineering. Due to various constraints, experimental data are extremely limited. Therefore, detailed numerical simulation can be considered as a desirable alternative. However, the physical processes involved in the impact are very sophisticated; hence a practical and complete reproduction of the phenomena involves complicated numerical models. In this paper, we present a smoothed particle hydrodynamics (SPH) method to model two-dimensional impact of metal sphere on thin metallic plate. The simulations are applied to different materials (Aluminum, Lead and Steel); however the target and projectile are formed of similar metals. A wide range of velocities (300, 1000, 2000, and 3100 m/s) are considered in this study. The goal is to study the most sensitive input parameters (impact velocity and plate thickness) on the longitudinal extension of the projectile, penetration depth and damage crater.

关键词: smoothed particle hydrodynamics     high velocity impact     sensitivity analysis    

Fabrication of bimetallic Cu–Zn adsorbents with high dispersion by using confined space for gas adsorptive

《化学科学与工程前沿(英文)》   页码 1623-1631 doi: 10.1007/s11705-022-2202-y

摘要: The number of active components and their dispersion degree are two key factors affecting the performance of adsorbents. Here, we report a simple but efficient strategy for dispersing active components by using a confined space, which is formed by mesoporous silica walls and templates in the as-prepared SBA-15 (AS). Such a confined space does not exist in the conventional support, calcined SBA-15, which does not contain a template. The Cu and Zn precursors were introduced to the confined space in the AS and were converted to CuO and ZnO during calcination, during which the template was also removed. The results show that up to 5 mmol·g–1 of CuO and ZnO can be well dispersed; however, severe aggregation of both oxides takes place in the sample derived from the calcined SBA-15 with the same loading. Confined space in the AS and the strong interactions caused by the abundant hydroxyl groups are responsible for the dispersion of CuO and ZnO. The bimetallic materials were employed for the adsorptive separation of propene and propane. The samples prepared from the as-prepared SBA-15 showed superior performance to their counterparts from the calcined SBA-15 in terms of both adsorption capacity of propene and selectivity for propene/propane.

关键词: bimetallic adsorbents     confined space     mesoporous silica     propene/propane separation    

Ballistic behavior of plain and reinforced concrete slabs under high velocity impact

Chahmi OUCIF, Luthfi Muhammad MAULUDIN, Farid Abed

《结构与土木工程前沿(英文)》 2020年 第14卷 第2期   页码 299-310 doi: 10.1007/s11709-019-0588-5

摘要: This work presents a numerical simulation of ballistic penetration and high velocity impact behavior of plain and reinforced concrete slabs. In this paper, we focus on the comparison of the performance of the plain and reinforced concrete slabs of unconfined compressive strength 41 MPa under ballistic impact. The concrete slab has dimensions of 675 mm × 675 mm × 200 mm, and is meshed with 8-node hexahedron solid elements in the impact and outer zones. The ogive-nosed projectile is considered as rigid element that has a mass of 0.386 kg and a length of 152 mm. The applied velocities vary between 540 and 731 m/s. 6 mm of steel reinforcement bars were used in the reinforced concrete slabs. The constitutive material modeling of the concrete and steel reinforcement bars was performed using the Johnson-Holmquist-2 damage and the Johnson-Cook plasticity material models, respectively. The analysis was conducted using the commercial finite element package Abaqus/Explicit. Damage diameters and residual velocities obtained by the numerical model were compared with the experimental results and effect of steel reinforcement and projectile diameter were studies. The validation showed good agreement between the numerical and experimental results. The added steel reinforcements to the concrete samples were found efficient in terms of ballistic resistance comparing to the plain concrete sample.

关键词: Johnson-Holmquist-2     Johnson-Cook     reinforced concrete     damage     impact loads    

载人航天技术及其发展

戚发轫

《中国工程科学》 2000年 第2卷 第1期   页码 1-6

摘要:

太空是人类继陆地、海洋、大气层之后的第四活动领域。第四活动领域具有高真空、微重力、强辐射、改变昼夜节律等特点,为人类的发展带来了巨大的潜力和开发前景。以发展载人航天器为重点的、由航天员参与的载人航天技术是以对太空进行探索以及利用太空环境进行科学研究、资源开发与应用的综合工程技术,它是新技术群中的一个重要领域,是高技术密集的尖端科学技术。

文章从载人航天技术的概念、内容和发展载人航天技术的意义三个方面对载人航天技术进行阐述,说明载人航天技术对人类社会发展的重要性。文章还对世界载人航天技术发展的概况与未来的发展做了介绍,最后提出了中国发展载人航天技术的设想。

关键词: 载人航天     高技术     概念     发展    

Safety and serviceability assessment for high-rise tower crane to turbulent winds

Zhi SUN, Nin HOU, Haifan XIANG

《结构与土木工程前沿(英文)》 2009年 第3卷 第1期   页码 18-24 doi: 10.1007/s11709-009-0009-2

摘要: Tower cranes are commonly used facilities for the construction of high-rise structures. To ensure their workability, it is very important to analyze their response and evaluate their condition under extreme conditions. This paper proposes a general scheme for safety and serviceability assessment of high-rise tower crane to turbulent winds based on time domain buffeting response analysis. Spatially correlated wind velocity field at the location of the tower crane was first simulated using an algorithm for generating the time domain samples of a stationary, multivariate stochastic process according to some prescribed spectral density matrix. The buffeting forces applied to the structure were computed according to the above-simulated wind velocity fluctuations and the lift, drag, and moment coefficients obtained from a CFD computation. Those spatially correlated loads were then fed into a well calibrated finite element model and the nonlinear time history analysis was conducted to compute structural buffeting response. Compared with structural on-site response measurement, the computed response using the proposed method has good precision. The proposed method is then adopted for analyzing the buffeting response of an in-use tower crane under the design wind speed and the maximum operational wind speed for safety and serviceability assessment.

关键词: tower crane     buffeting response     wind velocity     modeling    

Prediction of the shear wave velocity

Amoroso SARA

《结构与土木工程前沿(英文)》 2014年 第8卷 第1期   页码 83-92 doi: 10.1007/s11709-013-0234-6

摘要: The paper examines the correlations to obtain rough estimates of the shear wave velocity from non-seismic dilatometer tests (DMT) and cone penetration tests (CPT). While the direct measurement of is obviously preferable, these correlations may turn out useful in various circumstances. The experimental results at six international research sites suggest that the DMT predictions of from the parameters (material index), (horizontal stress index), (constrained modulus) are more reliable and consistent than the CPT predictions from (cone resistance), presumably because of the availability, by DMT, of the stress history index .

关键词: horizontal stress index     shear wave velocity     flat dilatometer test     cone penetration test    

高速线材吐丝机吐丝管空间曲线研究和改进

刘宏民,姚双吉,杨利坡,庞志峰,李双来,刘武斌,闫胜友,褚建东

《中国工程科学》 2006年 第8卷 第11期   页码 80-85

摘要:

针对唐钢高线吐丝机存在的吐丝质量问题,采用三次样条拟合现场实测数据得到吐丝管曲线方程;根据吐丝管中线材的速度和受力模型,分析线材在吐丝管中的运动状态,研究吐丝管空间曲线对吐丝质量的影响,得到吐丝管空间曲率波动过大和出口速度变化过快是导致吐丝质量不好的主要原因;通过改善吐丝管空间曲线和规范煨管工艺制度,显著改善了甩尾、吐圈摆动等吐丝质量,吐丝管寿命提高了1倍。

关键词: 高速吐丝机     吐丝管     空间曲线    

Experimental study on velocity characteristics of recirculation zone in humid air non-premixed flame

GU Xin, ZANG Shusheng, GE Bing

《能源前沿(英文)》 2008年 第2卷 第2期   页码 140-144 doi: 10.1007/s11708-008-0037-y

摘要: To examine the effect of the flow field within the recirculation zone on flame structure, the characteristic velocity fields of methane/humid air flame in non-premixed combustion behind a disc bluff-body burner were experimentally studied by particle image velocimeter (PIV).The results show that two stagnation points exist on the centerline in the recirculation zone flame. However, the distance of the two stagnation points in humid air combustion shortens, and the minimal dimensionless velocity increases compared with the conventional non-humid air combustion. In addition, the positional curves of the minimal velocities can be partitioned into three phases representing three different flame patterns. The analysis of axial minimal velocities on the centerline and their positions under different co-flow air velocity conditions reveals that fuel-to-air velocity ratio is the crucial parameter that governs humid air combustion flame characteristics.

关键词: distance     bluff-body     fuel-to-air velocity     stagnation     parameter    

Imaging studies of in-cylinder HCCI combustion

Pawel LUSZCZ, Hongming XU, Mirek WYZSNSKI, Xiao MA, Rob STEVENS, Athanasios TSOLAKIS

《能源前沿(英文)》 2011年 第5卷 第3期   页码 313-321 doi: 10.1007/s11708-011-0154-x

摘要: An optically accessed, single cylinder engine operated in homogenous charge compression ignition (HCCI) mode with negative valve overlap (NVO) strategy was used to perform combustion processes diagnostics under premixed conditions corresponding to the low load regime of the HCCI operational envelope. The aforementioned processes analysis was conducted utilizing synchronized simultaneous combustion event crank-angle resolved images, acquired through piston crown window with in-cylinder pressure recording. This investigation was carried out for one-step ignition fuel—standard gasoline, fuel proceeding single-stage ignition process under conditions studied. The initial combustion stage is characterized by a maximum local reaction spreading velocity in the range of 40–55 m/s. The later combustion stage reveals values as high as 140 m/s in case of stoichiometric combustion. The mixture as well as combustion stages effects are pronounced in these observed analytical results.

关键词: high speed imaging     combustion     homogenous charge compression ignition (HCCI)     reaction spreading velocity    

Design and characteristics of electric supercharger for diesel engine acceleration by additional rapid air injection

YAO Chun-de, ZHOU Hong-xiu

《机械工程前沿(英文)》 2006年 第1卷 第4期   页码 409-412 doi: 10.1007/s11465-006-0048-5

摘要: The ES (electric supercharger) driven by a high-speed brushless motor was developed to solve the problem of smoke caused by the turbocharger s sluggish response during acceleration. Its rotation speed was from 6 000 r/min to 24 000 r/min, and the maximum flux was 0.1 kg/s. The structural design of the electric supercharger is novel, which makes it easier to set the lubricating installation and to assemble. The velocity distribution at the outlet of the electric supercharger is determined by hot-wire anemometry under various rotation speeds in steady state. Furthermore, the trends of the flux and charge rate with various speeds were analyzed. In addition, the transient response was detected from the motor setup to smooth running within 10 s, 15 s, 20 s and 25 s respectively, and the characteristic of the transient flux is under pilot study. Research results indicate that the electric supercharger can respond rapidly with the great flux, and it is independent of the operating conditions of a diesel engine. Therefore, it is a feasible way to reduce smoke emission and improve the acceleration performance.

关键词: acceleration     velocity distribution     high-speed brushless     turbocharger     electric supercharger    

Technology improvements and management innovations in construction of Xiluodu hydropower station on Jinsha River

Qixiang FAN

《工程管理前沿(英文)》 2017年 第4卷 第2期   页码 231-237 doi: 10.15302/J-FEM-2017103

摘要: Hongtao ZHOU, Hongwei WANG, Wei ZENG. [J]. Front. Eng, 2018, 5(1): 78-87.Peter REDFERN, Hua ZHONG. [J]. Front. Eng, 2017, 4(2): 193-200.Ming-zhou Liu,Cong-hu Liu,Mao-gen Ge,Yuan Zhang,Qing-hua Zhu. [J]. Front. Eng, 2016, 3(2): 144-146.Chong-guang Feng,Hao Hu,Feng Xu,Jian Yang. [J]. Front. Eng, 2015, 2(2): 178-181.Yu Zhao,Sheng-quan Wang,Ke-chao Zhu. [J]. Front. Eng, 2015, 2(1): 35-38.Ru-gui Chen,Jia-meng Chen. [J]. Front. Eng, 2014, 1(1): 52-61.An Wang. [J]. Front. Eng, 2014, 1(1): 13-17.

关键词: super-high arch dam     intelligent construction     mass concrete temperature control     structure behavior control     anti-erosion concrete     low-heat portland cement     large-discharge and high-velocity spillway tunnels     large scale underground powerhouse     green hydropower station     sustainable development     Xiluodu hydropower station    

definition of metabolic dysfunction-associated fatty liver disease with elevated brachial-ankle pulse wave velocity

《医学前沿(英文)》 2022年 第16卷 第5期   页码 714-722 doi: 10.1007/s11684-021-0888-8

摘要: A new definition of metabolic dysfunction-associated fatty liver disease (MAFLD) has recently been proposed. We aim to examine the associations of MAFLD, particularly its discordance from non-alcoholic fatty liver disease (NAFLD), with the progression of elevated brachial-ankle pulse wave velocity (baPWV) and albuminuria in a community-based study sample in Shanghai, China. After 4.3 years of follow-up, 778 participants developed elevated baPWV and 499 developed albuminuria. In comparison with the non-MAFLD group, the multivariable adjusted odds ratio (OR) of MAFLD group for new-onset elevated baPWV was 1.25 (95% confidence interval (CI) 1.01–1.55) and 1.35 (95% CI 1.07–1.70) for albuminuria. Participants without NAFLD but diagnosed according to MAFLD definition were associated with higher risk of incident albuminuria (OR 1.77; 95% CI 1.07–2.94). Patients with MAFLD with high value of hepamet fibrosis score or poor-controlled diabetes had higher risk of elevated baPWV or albuminuria. In conclusion, MAFLD was associated with new-onset elevated baPWV and albuminuria independently of body mass index, waist circumference, and hip circumference. Individuals without NAFLD but diagnosed as MAFLD had high risk of albuminuria, supporting that MAFLD criteria would be practical for the evaluation of long-term risk of subclinical atherosclerosis among fatty liver patients.

关键词: metabolic dysfunction-associated fatty liver disease     non-alcoholic fatty liver disease     fibrosis score     brachial-ankle pulse wave velocity     albuminuria    

The “Tiangong” Chinese Space Station project

Yang HONG

《工程管理前沿(英文)》 2018年 第5卷 第2期   页码 278-283 doi: 10.15302/J-FEM-2018202

关键词: manned space station     space station project     basic design    

空间激光通信技术发展现状及展望

王天枢,林鹏,董芳,刘显著,马万卓,付强

《中国工程科学》 2020年 第22卷 第3期   页码 92-99 doi: 10.15302/J-SSCAE-2020.03.014

摘要:

空间激光通信技术是未来空间宽带信息传输的主要通信技术,具有带宽高、传输快速便捷及成本低的优势,是解决信息传输“最后一千米”的最佳选择。本文旨在系统把握空间激光通信技术的发展脉络,系统梳理了国内外空间激光通信技术在星地、星间、空地、空空等链路的研究与试验验证的发展情况,总结了激光通信技术在捕获跟踪、通信收发、大气补偿和光机设计等方向的关键技术研究热点。在此基础上,面向未来需求,归纳了空间激光通信技术在高速率、网络化、多用途、一体化、多谱段5 个方面的发展趋势。为进一步推动空间激光通信技术研究和产业化的发展,本文从实施基础研究计划、重视核心元器件研发、积极参与国际技术标准的制定以及引导相关产业发展4 个方面提出了发展建议,以期更好地促进我国空间激光通信技术的成果转化和应用。

关键词: 空间激光通信,天地一体化信息网络,高速率,激光组网,一对多激光通信    

标题 作者 时间 类型 操作

NO oxidation over Co-La catalysts and NO

Tiejun Zhang,Jian Li,Hong He,Qianqian Song,Quanming Liang

期刊论文

High velocity impact of metal sphere on thin metallic plate using smooth particle hydrodynamics (SPH)

Hossein ASADI KALAMEH, Arash KARAMALI, Cosmin ANITESCU, Timon RABCZUK

期刊论文

Fabrication of bimetallic Cu–Zn adsorbents with high dispersion by using confined space for gas adsorptive

期刊论文

Ballistic behavior of plain and reinforced concrete slabs under high velocity impact

Chahmi OUCIF, Luthfi Muhammad MAULUDIN, Farid Abed

期刊论文

载人航天技术及其发展

戚发轫

期刊论文

Safety and serviceability assessment for high-rise tower crane to turbulent winds

Zhi SUN, Nin HOU, Haifan XIANG

期刊论文

Prediction of the shear wave velocity

Amoroso SARA

期刊论文

高速线材吐丝机吐丝管空间曲线研究和改进

刘宏民,姚双吉,杨利坡,庞志峰,李双来,刘武斌,闫胜友,褚建东

期刊论文

Experimental study on velocity characteristics of recirculation zone in humid air non-premixed flame

GU Xin, ZANG Shusheng, GE Bing

期刊论文

Imaging studies of in-cylinder HCCI combustion

Pawel LUSZCZ, Hongming XU, Mirek WYZSNSKI, Xiao MA, Rob STEVENS, Athanasios TSOLAKIS

期刊论文

Design and characteristics of electric supercharger for diesel engine acceleration by additional rapid air injection

YAO Chun-de, ZHOU Hong-xiu

期刊论文

Technology improvements and management innovations in construction of Xiluodu hydropower station on Jinsha River

Qixiang FAN

期刊论文

definition of metabolic dysfunction-associated fatty liver disease with elevated brachial-ankle pulse wave velocity

期刊论文

The “Tiangong” Chinese Space Station project

Yang HONG

期刊论文

空间激光通信技术发展现状及展望

王天枢,林鹏,董芳,刘显著,马万卓,付强

期刊论文