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LianSheng Tang,Jing Song,HaoKun Chen,Ya Wang,JinLong Yin,JinLong Ye 한국지질과학협의회 2017 Geosciences Journal Vol.21 No.5
The vacuum preloading method combining prefabricated vertical drains (PVDs) and surcharge preloading from vacuum pressure is widely used in the improvement of dredger fill foundation. However, a clogging effect arises within the soils around the PVDs during the vacuum preloading, which significantly affects the soil consolidation. Previous studies indicated that the organic matter and soil pH circumstance influence the soil-water interaction and soil microstructure. In order to investigate the influences of organic matter and soil pH on the consolidation of clayey dredger fill, a series of small scale vacuum preloading tests was conducted on soils with different organic contents and soil pH values. Subsequently, Scanning Electron Microscopy observation test and vane shear test were carried out to evaluate the effect of vacuum preloading consolidation. The results showed that a low organic content or a high soil pH is beneficial for soil consolidation by vacuum preloading method, resulting in a more compact microstructure and a greater vane strength. There are two actions on the organic matter during the vacuum preloading consolidation, namely, material migration and organic matter dissolution. The organic matter dissolution effect is predominate at soil pH > 9.1, so that the consolidation effect is improved. However, the material migration effect is predominate at pH = 8.1, clay particles and organic matter can be transported with the water flow and redeposit near the drain pipes, resulting in a clogging effect. Moreover, a higher pH can induce the change of microstructure from flocculated association to deflocculated and dispersed association of clay particles, which is positive to soil consolidation. The results in this paper may offer helpful references for engineering practice.
Liansheng Zhang,Shuang Hao,Pengcheng Zhang,Qiangxian Huang,Rongjun Cheng,Ruijun Li,Ping Wang 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.12
Piezoelectric actuators have been widely applied to precision positioning platforms. However, the positioning accuracy of piezoelectric ceramic has been significantly affected by its characteristics of hysteresis. Owing to the voltage-keeping feature of capacitive load for piezoelectric ceramic, this paper has proposed a switch-based driving in sequence method, which alternately drives each layer of PZT by using switches. Based on the driving in sequence method, the proposed method is capable of reducing the hysteresis to 1/N of the hysteresis under traditional voltage driving method, while significantly lowering the scale and cost of hardware, compared with the previous driving in sequence method. Thus, it allows for application to hundreds of layers of piezoelectric ceramic. According to experiment results, the hysteresis under different frequencies from 0.1 to 500 Hz for homemade seven-layer piezoelectric ceramic can be reduced from 12.5 to 2.1%. Furtherly, the residual hysteresis can be corrected by applying a simple quadratic-polynomial feedforward control, and the hysteresis is constrained within 0.8%, even with feedforward parameters that are not strictly calibrated. The dual-amplifier driving in sequence method proposed in this paper can significantly reduce the hysteresis in open-loop control of piezoelectric stack actuators, effectively improving the positioning and driving performance and saving cost.
Xihong Zhao,Li Wang,Jin Chu,Yanmei Li,Yanyan Li,Zhenbo Xu,Lin Li,Mark E. Shirtliff,Xiaowei He,Yao Liu,Jihua Wang,Liansheng Yang 한국식품과학회 2010 Food Science and Biotechnology Vol.19 No.6
A loop-mediated isothermal amplification (LAMP) method for rapid detection of the food-borne Salmonella strains had been developed and evaluated in this study. The optimal reaction condition was found to be 65℃ for 45 min, with the detection limit as 1 pg DNA/tube and 100 CFU/reaction. Application of LAMP assays was performed on 214 food-borne Salmonella strains using a rapid procedure and easy result confirmation, where the specificity of LAMP and polymerase chain reaction (PCR)assays was 97.7% (209/214) and 91.6% (196/214),respectively; with a 100% specificity for both assays.
Xihong Zhao,Li Wang,Jin Chu,Yanyan Li,Yanmei Li,Lin Li,Mark E. Shirtliff,Xiaowei He,Yao Liu,Jihua Wang,Liansheng Yang,Zhenbo Xu 한국식품과학회 2010 Food Science and Biotechnology Vol.19 No.5
A loop-mediated isothermal amplification (LAMP) method for rapid detection of the foodborne Vibrio parahaemolyticus strains and related virulent factors had been developed and evaluated in this study. Six primers, including outer primers, inner primers, and loop primers, were specially designed for recognizing 8 distinct sequences on 3 target genes, which were tlh, tdh, and trh. The detection limits were found to be 100, 100 fg, and 1 pg DNA/tube for tlh, tdh, and trh, respectively. Application of LAMP assays were performed on 368 foodborne V. parahaemolyticus strains, the sensitivities of LAMP assays for the tlh, tdh, and trh were 100, 95.6, and 96.4%, and the negative predictive values (NPV) were 100, 84.7, and 93.1%, respectively; with a 100% specificity and positive predictive value (PPV) for all 3 target genes.
High Precision and Low Force Resonant Probe Based on Quartz Tuning Fork
Qiangxian Huang,Wenqian Wang,Guangpu Wang,Rongjun Cheng,Liansheng Zhang,Hongli Li,Ruijun Li 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.11
To realize the high-precision three-dimensional (3D) measurement of micro-precision devices, a 3D resonant trigger probe based on quartz tuning fork for micro/nano coordinate measuring machine (CMM) is proposed. The probe is composed of a quartz tuning fork, a tapered optical fiber stylus and a microsphere. It vibrates in resonance state and makes contact with the measured surface in the Z direction in tapping mode, while in the X and Y directions, it operates in friction mode. The 3D nano-positioning of the probe is achieved by the changes in resonance parameter caused by the interatomic force between the microsphere and the surface of the measured sample. In this study, the diameter of the probe microsphere can be as low as 80 μm, and the length of the probe stylus is approximately 5 mm. The trigger resolution of the probe in the X, Y and Z directions are 0.44, 0.41 and 0.34 nm, respectively. The probing forces in the X, Y and Z directions are 2.25, 1.81 and 4.24 μN, respectively. Experimental results verify that the proposed probe has the advantages of small size, sub-nano resolution and very low probing force. This probe can be used as the trigger probe of micro/nano CMM, which can be triggered by interatomic force.
Jinlong Lu,Guoguang Cheng,Julong Che,Liansheng Wang,Guojian Xiong 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.2
In this paper, the characteristics of tensile fractures and the typical inclusions in as-cast blooms and as-rolled bars are carefullyinvestigated to figure out the causes of different transverse tensile properties in two commercial non-quenched andtempered steels. In low Ca bearing steel (3 ppm), MgO–Al2O3 (MA) + MnS are main inclusions and MA oxides expresshigh ability for MnS heterogeneous nucleation. Consequently, the MnS inclusions in as-rolled bars are larger in size andsmaller in number, the transverse ductility is satisfied due to the high space distance between the MnS inclusions. However,the transverse ductility of high Ca bearing steel (9 ppm) is much poor because MnS inclusions are agminated in distribution,causing severe stress concentration. The calculation results show that CaO in CaO–MgO–Al2O3 oxides (CMA) wouldreact with Al and S in molten steels, suppressing the formation of MnS inclusions on surface of CMA oxides. An integratedillumination including the evolution processes of typical oxides in molten steels, the generation behaviors of MnS duringthe solidification, the deformation behaviors of sulfides and the relationship between sulfides and crack initiation have beenconducted based on observation results and thermodynamic calculation.