Grinding Damage of BK7 using Copper-Resin Bond Coarse-Grained Diamond Wheel

Qingliang Zhao,Junyun Chen,Haitao Huang,Xiaoyan Fang 한국정밀공학회 2011 International Journal of Precision Engineering and Vol. No.

Coarse-grained wheels can realize high efficient grinding of optical glass. However, the serious surface and subsurface damage will be inevitably introduced by the coarse-grained wheels. In this paper, the grinding damage of a copper-resin bond coarse-grained diamond wheel with grain size of 150μm was investigated on optical glass BK7. The wheel was first properly trued with a metal bond diamond wheel, then pre-dressing for the wheel and grinding experiments are carried out on a precision grinder assisted with electrolytic in process dressing (ELID) method. The surface roughness (Ra) of ground surface was measured using an atomic force microscope (AFM) and the surface topography were imaged by a white light interferometer (WLI) and the AFM. The subsurface damage level of ground surface was evaluated by means of both MRF spot method and taper polishing-etching method, in term of the biggest depth of subsurface damage, distribution of micro defects beneath the ground surface, the cluster depth of subsurface damage, relationship between subsurface damage (SSD)and PV surface roughness (SR), propagating distance and pattern of cracks beneath the ground surface. Experimental results indicate that a well conditioned copper-resin bond coarse-grained diamond wheel on a precision grinder can generate good surface quality of Ra less than 50nm and good subsurface integrity with SSD depth less than 3.5μm for optical glass BK7.

Modification of activated carbon from agricultural waste lotus leaf and its adsorption mechanism of beryllium

Xu Zhao,Yucheng Su,Hongqiang Wang,Zhiwu Lei,Eming Hu,Fang Hu,Qingliang Wang,Lechang Xu,Shiyao Fan,Xinwei Liu,Xuanzhang Hao 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.1

With the wide application of beryllium globally, industrial wastewater has rapidly increased. Previously, adsorption was effective in treating this issue. However, most adsorbents have a poor removal rate, primarily in the low adsorption capacity. To remove Be from industrial wastewater and overcome the disadvantages of low adsorption capacity and poor removal rate of existing adsorbents, typical agricultural waste lotus leaf was used to prepare Al-activated carbon (Al-AC) by the impregnation-calcination modification of Al(NO3)3. The theoretical maximum adsorption capacity of Al-AC was 32.86 mg/g. Langmuir, Freundlich, and Temkin models were used to thermodynamically analyze Al-AC, and adsorption thermodynamics demonstrated that the adsorption reaction of Al-AC was endothermic. Through characterization analysis, the specific surface area of the modified AC increased from 4.3573 to 155.87 m2/g. This study provides a new approach to preparing and modifying AC and a new method for removing Be from industrial wastewater.

Molecular Mechanisms of Tight Binding through Fuzzy Interactions

Shen, Qingliang,Shi, Jie,Zeng, Danyun,Zhao, Baoyu,Li, Pingwei,Hwang, Wonmuk,Cho, Jae-Hyun Elsevier 2018 Biophysical journal Vol.114 No.6

<P><B>Abstract</B></P> <P>Many intrinsically disordered proteins (IDPs) form fuzzy complexes upon binding to their targets. Although many IDPs are weakly bound in fuzzy complexes, some IDPs form high-affinity complexes. One example is the nonstructural protein 1 (NS1) of the 1918 Spanish influenza A virus, which hijacks cellular CRKII through the strong binding affinity (K<SUB>d</SUB> ∼10 nM) of its proline-rich motif (PRM<SUP>NS1</SUP>) to the N-terminal Src-homology 3 domain of CRKII. However, its molecular mechanism remains elusive. Here, we examine the interplay between structural disorder of a bound PRM<SUP>NS1</SUP> and its long-range electrostatic interactions. Using x-ray crystallography and NMR spectroscopy, we found that PRM<SUP>NS1</SUP> retains substantial conformational flexibility in the bound state. Moreover, molecular dynamics simulations showed that structural disorder of the bound PRM<SUP>NS1</SUP> increases the number of electrostatic interactions and decreases the mean distances between the positively charged residues in PRM<SUP>NS1</SUP> and the acidic residues in the N-terminal Src-homology 3 domain. These results are analyzed using a polyelectrostatic model. Our results provide an insight into the molecular recognition mechanism for a high-affinity fuzzy complex.</P>

Ultra-precision Ductile Grinding of Off-Axis Biconical Free-Form Optics with a Controllable Scallop Height Based on Slow Tool Servo with Diamond Grinding Wheels

Sheng Wang,Qingliang Zhao,Bing Guo 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.5

Free-form optics made of hard and brittle materials possesses the reflection and imaging functions that are difficult to be achieved by traditional optics and are widely used in various high energy space optical systems. However, free-form optics made of hard and brittle materials poses great challenges to ultra-precision machining due to its extreme demands of complex surface shapes with nonrotational asymmetric, submicron profile accuracy, controllable scallop height, nanometer surface roughness and ductile grinding surfaces. The freeform generation technique of the slow tool servo with diamond grinding wheel (STS-DGW) previously proposed by us was used to manufacture free-form optics made of hard and brittle materials. First, a theoretical model of scallop height during grinding of biconical free-form surface was established, and the effects of curvature changes on scallop height were studied. Subsequently, the profile error caused by the centering error of diamond wheel was calculated theoretically, and an accurate adjustment method of the grinding wheel position was proposed. Then, an undeformed chip thickness model for achieving ductile grinding was established, and the simulation calculation of critical grinding parameters was carried out. Ultimately, a typical off-axis biconical free-form optics with submicron profile accuracy, a controllable scallop height, nanometer surface roughness, and ductile grinding surfaces was successfully fabricated on single-crystal silicon using the proposed STS-DGW. Compared with the previous research, the profile accuracy was further improved, a controllable scallop height and ductile grinding surface was achieved.

Surface Micro-Structuring of Coarse-Grained Diamond Wheels by Nanosecond Pulsed Laser for Improving Grinding Performance

Bing Guo,Qingliang Zhao,Xinyu Zhao 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

The conditioned coarse-grained diamond wheels are able to achieve the identical surface roughness, higher form accuracy and largergrinding rate when compared to the traditional fine-grained diamond wheels. However, deeper subsurface damage could be inevitablyintroduced due to the flat tops of the coarse diamond grains. This work presents a micro-structuring method for coarse-graineddiamond wheels by means of nanosecond pulsed laser, which allows the generation of micro grooves arrays on the coarse diamondgrains distributed on the whole grinding wheel cylindrical surface. The influence of laser parameters such as focal point shift, laserpower, scanning speed and scanning passes on micro-structured surface was investigated, and then the laser machining process wasoptimized in fabricating uniform and continuous micro-structures. The grinding experiments indicate that, when compared to the nonmicro-structured grinding wheels, the subsurface cracks depth of ground optical glass was reduced effectually by using the microstructuredcoarse-grained diamond wheels.

Arc Envelope Grinding of Sapphire Steep Aspheric Surface with SiC-Reinforced Resin-Bonded Diamond Wheel

Jinhu Wang,Qingliang Zhao,Chunyu Zhang,Bing Guo,Julong Yuan 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.4

In order to improve the grinding wheel wear during the sapphire steep aspheric surface grinding process, a SiC-reinforced resin-bonded hemispherical diamond wheel was used and the arc envelope grinding performance was investigated. Firstly, the mapping relationship between the contours of the grinding wheel and the aspheric surface was established based on the grinding conditions. The wear of the hemispherical diamond wheel was modelled, and the result indicates that the maximum wear occurred at the edge of the hemisphere, decreases along the generatrix and increases near the center. Then, the formtrued diamond wheel was used for grinding the sapphire steep aspheric surface. The concave and convex surface form error obtained at the central part of Φ 50 mm are 2.5 μm and 1.3 μm, respectively. The surface roughness R a is 230–450 nm, which is affected by the material removal rate and the sapphire crystal anisotropy. The SiC-reinforced resin-bonded diamond wheel possesses favorable self-sharpening ability and sufficient diamond grain retention capacity for sapphire grinding. The wear distribution shows that the most severe wear parts of the grinding wheel are at the edge and the center of the grinding zone, which is consistent with the model-predicted results.

A Macrophyte Sediment Microbial Fuel Cell for Polluted Urban River Sedimnet Remediation and in-situ Bioenergy Generation

Felix Tetteh KABUTEY,Qingliang ZHAO,Jing DING,Philip ANTWI 대한환경공학회 2019 대한환경공학회 학술발표논문집 Vol.2019 No.-

Electrochemical removal of nitrogenous species for high salinity contained industrial wastewater effluent

Jing Ding,Guanshu Zhao,Qingliang Zhao,Fanyu Meng 대한환경공학회 2019 대한환경공학회 학술발표논문집 Vol.2019 No.-

High efficiency precision grinding of micro-structured SiC surface using laser micro-structured coarse-grain diamond grinding wheel

Mingtao Wu,Bing Guo,Qingliang Zhao,Jun Zhang,Xiaoyan Fang,Ping He 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.6 No.3

Accompanying with the extensive applications of micro-structured surfaces on hard and brittle material in MEMS and NEMS sensors, optical elements, electronic devices and medical products, efficiently fabricating of these surface has gradually become the focus of manufacturing community. Basing on precision grinding with conditioned and laser micro-structured coarse-grained diamond grinding wheel, a novel high efficiency technique for micro-structured surfaces on hard and brittle material, such as silicon carbide, was developed in this paper. Firstly, the maximum undeformed chip thickness for conditioned coarse-grained wheel and the ductile grinding of silicon carbide was theoretically and experimentally studied. Silicon carbide surface formed mainly in ductile regime was successfully achieved. And then, the strategy for micro-structuring the conditioned wheel with designed micro-structure geometry, sharp edge and small inclination angle side-wall was investigated. Finally, the linear and square micro-structured surfaces with high form accuracy and ultra-precision surface roughness were successfully and efficiently fabricated on silicon carbide by the technique developed in this paper.

Bioelectrochemical performance of microbial fuel cell powered electro-Fenton system (MFCⓅEFs) with composite PANI-Mn/CF anode

Jiaqi Lv,Weiye Wang,Qingliang Zhao,Kun Wang 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.4

Microbial fuel cell powered electro-Fenton system (MFCⓅEFs) is a self-sustainable energy conversion process to degrade refractory pollutants utilizing green biomass energy. Most previous works usually employed innovative cathode to minimize electron transfer losses but neglected the development of high-efficiency anode to enhance electron generation. The synergy of polyaniline (PANI) and MnO2 on electrode could improve charge accessibility and facilitate rapid electron transfer due to its superior conductivity and capacitance, which had not been applied to MFCⓅEFs as anode so far. In this study, a PANI-Mn/CF (carbon fiber loaded with polyaniline and MnO2) composite anode was introduced into MFCⓅEFs to enhance interface activity and realize more efficient electricity generation and pollutant degradation. Experimental results showed that a higher power density (5.49 times that of the original CF) and lower ohmic resistance (7.17 Ω) occurred in the MFCⓅEFs with PANI-Mn/CF anode, which consumed more sewage sludge (37.14% of TCOD removal), leading to achieving more effective pollutant degradation (93.03% of tetracycline hydrochloride removal). Overall, this study provided an innovative way of thinking and approach to efficient utilization of biomass waste and degradation of refractory pollutants with the merits of environmental sustainability.