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稳定性 11

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乳化炸药结构与稳定性关系的研究

汪旭光,申英锋

《中国工程科学》 2000年 第2卷 第2期   页码 24-29

摘要:

文章从结构角度出发,系统分析了乳化炸药乳胶体稳定性的各个因素,并得出了零渗透压体系在结构上最为稳定的结论。实验测定表明,几种较稳定的乳胶配方均接近为零渗透压体系。

关键词: 乳化炸药     结构     稳定性    

Performance and emission characteristics of a diesel engine operating on different water in diesel emulsion

Seyed Saeed HOSEINI, Mohammad Amin SOBATI

《能源前沿(英文)》 2019年 第13卷 第4期   页码 636-657 doi: 10.1007/s11708-019-0646-7

摘要: The nitrogen oxide (NO ) release of diesel engines can be reduced using water in diesel emulsion fuel without any engine modification. In the present paper, different formulations of water in diesel emulsion fuels were prepared by ultrasonic irradiation. The water droplet size in the emulsion, polydisperisty index, and the stability of prepared fuel was examined, experimentally. Afterwards, the performance characteristics and exhaust emission of a single cylinder air-cooled diesel engine were investigated using different water in diesel emulsion fuels. The effect of water content (in the range of 5%–10% by volume), surfactant content (in the range of 0.5%–2% by volume), and hydrophilic-lipophilic balance (HLB) (in the range of 5–8) was examined using Box-Behnken design (BBD) as a subset of response surface methodology (RSM). Considering multi-objective optimization, the best formulation for the emulsion fuel was found to be 5% water, 2% surfactant, and HLB of 6.8. A comparison was made between the best emulsion fuel and the neat diesel fuel for engine performance and emission characteristics. A considerable decrease in the nitrogen oxide emission (–18.24%) was observed for the best emulsion fuel compared to neat diesel fuel.

关键词: water in diesel emulsion fuel     hydrophilic-lipophilic balance (HLB)     response surface methodology (RSM)     emulsion stability     engine performance     exhaust emission    

Optimising the oil phases of aluminium hydrogel-stabilised emulsions for stable, safe and efficient vaccine adjuvant

《化学科学与工程前沿(英文)》 2022年 第16卷 第6期   页码 973-984 doi: 10.1007/s11705-021-2123-1

摘要: To increase antibody secretion and dose sparing, squalene-in-water aluminium hydrogel (alum)-stabilised emulsions (ASEs) have been developed, which offer increased surface areas and cellular interactions for higher antigen loading and enhanced immune responses. Nevertheless, the squalene (oil) in previous attempts suffered from limited oxidation resistance, thus, safety and stability were compromised. From a clinical translational perspective, it is imperative to screen the optimal oils for enhanced emulsion adjuvants. Here, because of the varying oleic to linoleic acid ratio, soybean oil, peanut oil, and olive oil were utilised as oil phases in the preparation of aluminium hydrogel-stabilised squalene-in-water emulsions, which were then screened for their stability and immunogenicity. Additionally, the underlying mechanisms of oil phases and emulsion stability were unravelled, which showed that a higher oleic to linoleic acid ratio increased anti-oxidative capabilities but reduced the long-term storage stability owing to the relatively low zeta potential of the prepared droplets. As a result, compared with squalene-in-water ASEs, soybean-in-water ASEs exhibited comparable immune responses and enhanced stability. By optimising the oil phase of the emulsion adjuvants, this work may offer an alternative strategy for safe, stable, and effective emulsion adjuvants.

关键词: pickering emulsion     vaccine adjuvant     alum-stabilised emulsion     oleic to linoleic acid ratio     stability    

Importance of emulsions in crystallization—applications for fat crystallization

Sandra PETERSEN, K. CHALEEPA, Joachim ULRICH

《化学科学与工程前沿(英文)》 2013年 第7卷 第1期   页码 43-48 doi: 10.1007/s11705-013-1309-6

摘要: Emulsions and crystallization are two independent research topics which normally do not overlap although a combination of the two could be applicable to many areas. Here, the importance of emulsions in the field of fat crystallization is described. Three applications with industrial relevance were chosen for investigation: fat fractionation, the solidification of phase change materials and solid lipid nanoparticles. For fat fractionation and phase change materials, emulsification can be applied as a tool to improve the fat crystallization process, and thus the product quality of the crystallized fat. Furthermore, the use of emulsification creates new application fields such as solid lipid nanoparticles in the area of fat crystallization.

关键词: emulsion     fat crystallization     phase change material     emulsion fractionation     emulsion solidification    

Solvates and polymorphs of clindamycin phosphate: Structural, thermal stability and moisture stability

Junbo Gong, Dejiang Zhang, Yuanyuan Ran, Keke Zhang, Shichao Du

《化学科学与工程前沿(英文)》 2017年 第11卷 第2期   页码 220-230 doi: 10.1007/s11705-017-1624-4

摘要: Clindamycin phosphate (CP), an antibacterial agent, has been reported to form several solid-state forms. The crystal structures of two CP solvates, a dimethyl sulfoxide (DMSO) solvate and a methanol/water solvate (solvate V), have been determined by single crystal X-ray diffraction. The properties and transformations of these forms were characterized by powder X-ray diffraction, Single-crystal X-ray diffraction, differential scanning calorimetry, thermo gravimetric analysis, hot-stage microscopy, and dynamic vapor sorption. Very different hydrogen bonding networks exist among the host-host and host-solvent molecules in the two crystal structures, resulting in different moisture stabilities. The thermal stabilities of the two solvates upon heating and desolvation were also studied. When the temperature was above the boiling point of methanol, solvate V converted to a polymorphic phase after a one step desolvation process, whereas the desolvation temperature of the DMSO solvate was below the boiling point of DMSO. At the relative humidity above 43%, the DMSO solvate transformed to a hydrate at 25 °C. In contrast, solvate V did not transform at any of the humidities studied.

关键词: clindamycin phosphate     solvate     crystal structure     thermal stability     moisture stability    

Evaluation and prediction of slope stability using machine learning approaches

《结构与土木工程前沿(英文)》 2021年 第15卷 第4期   页码 821-833 doi: 10.1007/s11709-021-0742-8

摘要: In this paper, the machine learning (ML) model is built for slope stability evaluation and meets the high precision and rapidity requirements in slope engineering. Different ML methods for the factor of safety (FOS) prediction are studied and compared hoping to make the best use of the large variety of existing statistical and ML regression methods collected. The data set of this study includes six characteristics, namely unit weight, cohesion, internal friction angle, slope angle, slope height, and pore water pressure ratio. The whole ML model is primarily divided into data preprocessing, outlier processing, and model evaluation. In the data preprocessing, the duplicated data are first removed, then the outliers are filtered by the LocalOutlierFactor method and finally, the data are standardized. 11 ML methods are evaluated for their ability to learn the FOS based on different input parameter combinations. By analyzing the evaluation indicators R 2, MAE, and MSE of these methods, SVM, GBR, and Bagging are considered to be the best regression methods. The performance and reliability of the nonlinear regression method are slightly better than that of the linear regression method. Also, the SVM-poly method is used to analyze the susceptibility of slope parameters.

关键词: slope stability     factor of safety     regression     machine learning     repeated cross-validation    

Porous ultrathin-shell microcapsules designed by microfluidics for selective permeation and stimuli-triggered release

《化学科学与工程前沿(英文)》   页码 1643-1650 doi: 10.1007/s11705-022-2201-z

摘要: Microcapsules are versatile delivery vehicles and widely used in various areas. Generally, microcapsules with solid shells lack selective permeation and only exhibit a simple release mode. Here, we use ultrathin-shell water-in-oil-in-water double emulsions as templates and design porous ultrathin-shell microcapsules for selective permeation and multiple stimuli-triggered release. After preparation of double emulsions by microfluidic devices, negatively charged shellac nanoparticles dispersed in the inner water core electrostatically complex with positively charged telechelic α,ω-diamino functionalized polydimethylsiloxane polymers dissolved in the middle oil shell at the water/oil interface, thus forming a porous shell of shellac nanoparticles cross-linked by telechelic polymers. Subsequently, the double emulsions become porous microcapsules upon evaporation of the middle oil phase. The porous ultrathin-shell microcapsules exhibit excellent properties, including tunable size, selective permeation and stimuli-triggered release. Small molecules or particles can diffuse across the shell, while large molecules or particles are encapsulated in the core, and release of the encapsulated cargos can be triggered by osmotic shock or a pH change. Due to their unique performance, porous ultrathin-shell microcapsules present promising platforms for various applications, such as drug delivery.

关键词: microcapsule     emulsion     microfluidics     selective permeation     stimuli-triggered release    

Modified Bishop method for stability analysis of weakly sloped subgrade under centrifuge model test

《结构与土木工程前沿(英文)》 2021年 第15卷 第3期   页码 727-741 doi: 10.1007/s11709-021-0730-z

摘要: The sliding forms of weak sloped and horizontal subgrades during the sliding process differ. In addition, the sliding form of weakly sloped subgrades exhibits considerable slippage and asymmetry. The accuracy of traditional slice methods for computing the stability safety factor of weakly sloped subgrades is insufficient for a subgrade design. In this study, a novel modified Bishop method was developed to improve the accuracy of the stability safety factor for different inclination angles. The instability mechanism of the weakly sloped subgrade was considered in the proposed method using the “influential force” and “additional force” concepts. The “additional force” reflected the weight effect of the embankment fill, whereas the “influential force” reflected the effect of the potential energy difference. Numerical simulations and experimental tests were conducted to evaluate the advantages of the proposed modified Bishop method. Compared with the traditional slice method, the error between the proposed method and the exact value is less than 32.3% in calculating the safety factor.

关键词: weakly sloped subgrade     stability analysis     additional force     influential force     modified Bishop method    

Effect of cutterhead configuration on tunnel face stability during shield machine maintenance outages

《结构与土木工程前沿(英文)》 2023年 第17卷 第4期   页码 522-532 doi: 10.1007/s11709-023-0930-9

摘要: Owing to long-distance advancement or obstacles, shield tunneling machines are typically shut down for maintenance. Engineering safety during maintenance outages is determined by the stability of the tunnel face. Pressure maintenance openings are typically used under complicated hydrogeological conditions. The tunnel face is supported by a medium at the bottom of the excavation chamber and compressed air at the top. Owing to the high risk of face failure, the necessity of support pressure when cutterhead support is implemented and a method for determining the value of compressed air pressure using different support ratios must to be determined. In this study, a non-fully chamber supported rotational failure model considering cutterhead support is developed based on the upper-bound theorem of limit analysis. Numerical simulation is conducted to verify the accuracy of the proposed model. The results indicate that appropriately increasing the specific gravity of the supporting medium can reduce the risk of collapse. The required compressed air pressure increases significantly as the support ratio decreases. Disregarding the supporting effect of the cutterhead will result in a tunnel face with underestimated stability. To satisfy the requirement of chamber openings at atmospheric pressure, the stratum reinforcement strength and range at the shield end are provided based on different cutterhead aperture ratios.

关键词: tunnel face stability     cutterhead configuration     aperture ratio     pressure gradient     support ratio    

Effect of undercut on the lower bound stability of vertical rock escarpment using finite element and

Shuvankar DAS; Debarghya CHAKRABORTY

《结构与土木工程前沿(英文)》 2022年 第16卷 第8期   页码 1040-1055 doi: 10.1007/s11709-022-0841-1

摘要: In the present study, the stability of a vertical rock escarpment is determined by considering the influence of undercut. Lower bound finite element limit analysis in association with Power Cone Programming (PCP) is applied to incorporate the failure of rock mass with the help of the Generalized Hoek-Brown yield criterion. The change in stability due to the presence of undercut is expressed in terms of a non-dimensional stability number (σci/γH). The variations of the magnitude of σci/γH are presented as design charts by considering the different magnitudes of undercut offset (H/vu and wu/vu) from the vertical edge and different magnitudes of Hoek-Brown rock mass strength parameters (Geological Strength Index (GSI), rock parameter (mi,), Disturbance factor (D)). The obtained results indicate that undercut can cause a severe stability problem in rock mass having poor strength. With the help of regression analysis of the computed results, a simplified design equation is proposed for obtaining σci/γH. By performing sensitivity analysis for an undisturbed vertical rock escarpment, we have found that the undercut height ratio (H/vu) is the most sensitive parameter followed by GSI, undercut shape ratio (wu/vu), and mi. The developed design equation as well as design charts can be useful for practicing engineers to determine the stability of the vertical rock escarpment in the presence of undercut. Failure patterns are also presented to understand type of failure and extent of plastic state during collapse.

关键词: undercut     vertical escarpment     stability     Hoek-Brown yield criterion     PCP    

Correction to: Effect of undercut on the lower bound stability of vertical rock escarpment using finite

《结构与土木工程前沿(英文)》 doi: 10.1007/s11709-023-0035-5

摘要: Correction to: Effect of undercut on the lower bound stability of vertical rock escarpment using finite element and power cone programming

关键词: finite element power     stability rock escarpment    

TiO@palygorskite composite for the efficient remediation of oil spills via a dispersion-photodegradation synergy

《环境科学与工程前沿(英文)》 2021年 第15卷 第4期 doi: 10.1007/s11783-020-1365-3

摘要:

• A novel and multi-functional clay-based oil spill remediation system was constructed.

关键词: Palygorskite     TiO2     Pickering emulsion     Oil spill     Dispersion     Photodegradation    

Influence of boundary conditions and turntable speeds on the stability of hydrostatic oil cavity

Zhaomiao LIU, Chengyin ZHANG, Feng SHEN

《机械工程前沿(英文)》 2011年 第6卷 第3期   页码 359-368 doi: 10.1007/s11465-011-0222-2

摘要:

The flow, bearing, and carrying capacity of the cycloidal hydrostatic oil cavity in hydrostatic turntable systems are numerically simulated, considering the rotation speeds of a turntable from 0 to 5 m/s and different boundary conditions. The vortex effect is weakened, and the stability of the oil cavity is enhanced with the increase in lubricant viscosity. However, the increase in inlet speed, depth, and inlet radius of the oil cavity causes the vortex effect to increase and the stability of oil cavity to reduce. With the increase in the oil film thickness, the carrying capacity of the oil cavity diminishes. The oil cavity pressure increases along the direction of the motion of the turntable; it is distributed unevenly because of the rotation of the turntable. With the increase in turntable speed, the location and size of the vortex scope in the oil cavity flow field and the strength of the vortex near the entrance gradually weaken and move away from the entry. The distribution of pressure is determined by the locations of the vortex. When the vortex is close to the wall, the wall pressure increases at its location. Otherwise, the wall pressure decreases first and then increases after the center of the vortex.

关键词: hydrostatic oil cavity     flow state     oil cavity pressure     stability     vortex    

Three-dimensional stability analysis of the dam foundation at Baise

XU Qianjun, LI Xu, CHEN Zuyu

《结构与土木工程前沿(英文)》 2007年 第1卷 第2期   页码 217-221 doi: 10.1007/s11709-007-0026-y

摘要: It is usually difficult to determine the actual safety factors of rock masses in an ordinary two-dimensional stability analysis if the safety factors of the different cross sections in the rock mass vary significantly. In addition to the actual slope, arch dam abutment, and the actual foundation of a high building, another example is that the different cross sections of the foundation in the monolith of a gravity dam vary significantly, just like the condition at the overflow dam in the Baise project. A three-dimensional stability analysis method based on the upper-bound theorem was employed to solve this problem. The parameters used in the analysis were obtained from geomechanics tests, as well as continuity simulations of the randomly distributed joints. Two failure patterns against sliding are analyzed. One pattern is the foundation slide along deep-seated planes which were determined by calculations. The other pattern is the foundation slide along the planes across the bottom of the high steps in the foundation pit. The results indicate that a special overflow dam monolith can be considered to be safe in case of considering the three dimensional effect. However, a key wall with a depth of 5m must be constructed at the upper side of this monolith in order to ensure the safety of the foundation.

关键词: ordinary two-dimensional     randomly     monolith     three-dimensional stability     different    

Design and stability analysis of continuous skew tied-arch bridge over Bin Jiang River

YU Jiancheng, TONG Hao, HUANG Wei

《结构与土木工程前沿(英文)》 2008年 第2卷 第1期   页码 37-42 doi: 10.1007/s11709-008-0004-z

摘要: A tied arch bridge without wind bracing was built over the Bin Jiang River, with oblique angle of 20°. Its main design details are described and mechanical performances are analyzed. The stability analytical types are also introduced and the first elastic stability theory is used. A space finite element model has been built to analyze the stability performances in both construction and operation stages for single span or continuous, orthogonal or oblique bridge. The influence of stiffness of the end crossbeam is also analyzed. The result shows that out-plane buckling occur for a rigid tie and similar no matter whether it is single span or continuous and orthogonal or oblique. When there are more and stronger inner crossbeams, the influence of the end crossbeams on arch stability becomes unremarkable.

关键词: out-plane buckling     unremarkable     crossbeam     stability analytical     orthogonal    

标题 作者 时间 类型 操作

乳化炸药结构与稳定性关系的研究

汪旭光,申英锋

期刊论文

Performance and emission characteristics of a diesel engine operating on different water in diesel emulsion

Seyed Saeed HOSEINI, Mohammad Amin SOBATI

期刊论文

Optimising the oil phases of aluminium hydrogel-stabilised emulsions for stable, safe and efficient vaccine adjuvant

期刊论文

Importance of emulsions in crystallization—applications for fat crystallization

Sandra PETERSEN, K. CHALEEPA, Joachim ULRICH

期刊论文

Solvates and polymorphs of clindamycin phosphate: Structural, thermal stability and moisture stability

Junbo Gong, Dejiang Zhang, Yuanyuan Ran, Keke Zhang, Shichao Du

期刊论文

Evaluation and prediction of slope stability using machine learning approaches

期刊论文

Porous ultrathin-shell microcapsules designed by microfluidics for selective permeation and stimuli-triggered release

期刊论文

Modified Bishop method for stability analysis of weakly sloped subgrade under centrifuge model test

期刊论文

Effect of cutterhead configuration on tunnel face stability during shield machine maintenance outages

期刊论文

Effect of undercut on the lower bound stability of vertical rock escarpment using finite element and

Shuvankar DAS; Debarghya CHAKRABORTY

期刊论文

Correction to: Effect of undercut on the lower bound stability of vertical rock escarpment using finite

期刊论文

TiO@palygorskite composite for the efficient remediation of oil spills via a dispersion-photodegradation synergy

期刊论文

Influence of boundary conditions and turntable speeds on the stability of hydrostatic oil cavity

Zhaomiao LIU, Chengyin ZHANG, Feng SHEN

期刊论文

Three-dimensional stability analysis of the dam foundation at Baise

XU Qianjun, LI Xu, CHEN Zuyu

期刊论文

Design and stability analysis of continuous skew tied-arch bridge over Bin Jiang River

YU Jiancheng, TONG Hao, HUANG Wei

期刊论文