How Did Reviewers Give Their Reviews? Characterizing Review Activity in Academic Conferences

Zhiwen Yu,Xinxin Zhang,Yunji Liang,Daqing Zhang 보안공학연구지원센터 2013 International Journal of Multimedia and Ubiquitous Vol.8 No.5

Effect of Ultrasonic Power on Grain Refinement and Purification Processing of AZ80 Alloy by Ultrasonic Treatment

Zhiwen Shao,Qichi Le,Zhiqiang Zhang,Jianzhong Cui 대한금속·재료학회 2012 METALS AND MATERIALS International Vol.18 No.2

Ultrasound with different powers was applied to treat AZ80 alloy melt to attain grain refinement or purifi-cation processing of the alloy. The influence of ultrasonic powers from 0 W to 1400 W on microstruc-tures of the AZ80 alloy with ultrasonic grain refinement treatment was investigated. The average grain size of the alloy could be decreased from 387 µm to 147 µm after the ultrasound with the optimal power 600 W was applied to treat the melt. The effect of ultrasonic powers from 0 W to 230 W on the inclusion distribution in the ingot that was treated by ultrasonic purification processing was also studied. The opti-mal ultrasonic power in the ultrasonic purification processing was 80 W. In order to gain insight into the mechanism by which ultrasonic power affected the microstructure of the alloy or inclusion distribution in the ingot, numerical simulations were carried out and the ultrasonic field propagation in the melt was characterized.

Impact of axial power distribution on thermal-hydraulic characteristics for thermionic reactor

Zhiwen Dai,Chenglong Wang,Dalin Zhang,Wenxi Tian,Suizheng Qiu,G.H. Su 한국원자력학회 2021 Nuclear Engineering and Technology Vol.53 No.12

Reactor fuel's power distribution plays a vital role in designing the new generation thermionic SpaceReactor Power Systems (SRPS). In this paper, the 1/12th SPACE-R's full reactor core was numericallyanalyzed with two kinds of different axial power distribution, to identify their impacts on thermalhydraulic and thermoelectric characteristics. In the benchmark study, the maximum error betweennumerical results and existing data or design values ranged from 0.2 to 2.2%. Four main conclusions wereobtained in the numerical analysis: a) The axial power distribution has less impact on coolant temperature. b) Axial power distribution influenced the emitter temperature distribution a lot, when the corepower was cosine distributed, the maximum temperature of the emitter was 194 K higher than that ofthe uniform power distribution. c) Comparing to the cosine axial power distribution, the uniform axialpower distribution would make the maximum temperature in each component of the reactor core muchlower, reducing the requirements for core fuel material. d) Voltage and current distribution were similarto the axial electrode temperature distribution, and the axial power distribution has little effect on theoutput power

Continuous Pad Dyeing of Cotton Fabric in a Non-Aqueous Medium for Realizing Ultra-High Fixation and Washing-Free

Zhiwen Wang,Liujun Pei,Hongjuan Zhang,Hao Li,Jiping Wang 한국섬유공학회 2022 Fibers and polymers Vol.23 No.5

In traditional water-based dyeing system, a low fixation of reactive dye requires six to ten times washing afterdyeing, which consumes a lot of water and results in huge dyeing effluent. To alleviate this issue, the development of asustainable dyeing technology of cotton textile is essential. In the present investigation, silicone non-aqueous medium wasemployed to improve the fixation of dye with a pad-dyeing process under the optimized dyeing parameters. The appropriatewashing-free dyeing conditions were recommended as follows: the padded fabric was placed at 105 oC for 15-30 s tocomplete pre-drying to decrease the water content rapidly, and then fixed in non-aqueous medium for 80-90 s at 95 oC. Afterdyeing, the dyed fabric was treated with 30 g/l fixing agent through pre-dried at 80 oC and baked at 160 oC. The resultsindicated that the final fixation of dye was above 95 %, and the dry rubbing fastness of dyed cotton fabric can reach grade 5. Moreover, the wet rubbing fastness and washing fastness of dyed cotton fabric can reach grade 3-4 and 4, respectively. Therefore, it can obtain the washing-free dyeing of cotton fabric with reactive dye. If the washing procedure was omitted inthe industrial application, the environmental cost of cotton dyeing would be greatly decreased. This method provides asubstantial reduction in wastewater effluent, which will be considerably potential for industrial application.

Design and heat transfer optimization of a 1 kW free-piston stirling engine for space reactor power system

Dai, Zhiwen,Wang, Chenglong,Zhang, Dalin,Tian, Wenxi,Qiu, Suizheng,Su, G.H. Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.7

The Free-Piston Stirling engine (FPSE) is of interest for many research in aerospace due to its advantages of long operating life, higher efficiency, and zero maintenance. In this study, a 1-kW FPSE was proposed by analyzing the requirements of Space Reactor Power Systems (SRPS), of which performance was evaluated by developing a code through the Simple Analysis Method. The results of SAM showed that the critical parameters of FPSE could satisfy the designed requirements. The heater of the FPSE was designed with the copper rectangular fins to enhance heat transfer, and the parametric study of the heater was performed with Computational Fluid Dynamics (CFD) software STAR-CCM⁺. The Performance Evaluation Criteria (PEC) was used to evaluate the heat transfer enhancement of the fins in the heater. The numerical results of the CFD program showed that pressure drop and Nusselt number ratio had a linear growth with the height of fins, and PEC number decreased as the height of fins increased, and the optimum height of the fin was set as 4 mm according to the minimum heat exchange surface area. This paper can provide theoretical supports for the design and numerical analysis of an FPSE for SRPSs.

glyA Gene Knock-out in Escherichia coli Enhances L-serine Production without Glycine Addition

Ya Zhang,Pei Kang,Shuang Liu,Yujiao Zhao,Zhiwen Wang,Tao Chen 한국생물공학회 2017 Biotechnology and Bioprocess Engineering Vol.22 No.4

In E. coli, glyA encodes for serine hydroxymethyltransferase (SHMT), which converts L-serine to glycine. When engineering L-serine-producing strains, it is therefore favorable to inactivate glyA to prevent L-serine degradation. However, most glyA knockout strains exhibit slow cell growth because of the resulting lack of glycine and C1 units. To overcome this problem, we overexpressed the gcvTHP genes of the glycine cleavage system (GCV), to increase the C1 supply before glyA was knocked out. Subsequently, the kbl and tdh genes were overexpressed to provide additional glycine via the L-threonine degradation pathway, thus restoring normal cell growth independent of glycine addition. Finally, the plasmid pPK10 was introduced to overexpress pgk, serAΔ197, serC and serB, and the resulting strain E4G2 (pPK10) accumulated 266.3 mg/L of L-serine in a semi-defined medium without adding glycine, which was 3.18-fold higher than the production achieved by the control strain E3 (pPK10). This strategy can accordingly be applied to disrupt the L-serine degradation pathway in industrial production strains without causing negative side-effects, ultimately making L-serine production more efficient.

Design and analysis of a free-piston stirling engine for space nuclear power reactor

Dai, Zhiwen,Wang, Chenglong,Zhang, Dalin,Tian, Wenxi,Qiu, Suizheng,Su, G.H. Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.2

The free-piston Stirling engine (FPSE) has been widely used in aerospace owing to its advantages of high efficiency, high reliability, and self-starting ability. In this paper, a 20-kW FPSE is proposed by analyzing the requirements of space nuclear power reactor. A code was developed based on an improved simple analysis method to evaluate the performance of the proposed FPSE. The code is benchmarked with experimental data, and the maximum relative error of the output power is 17.1%. Numerical results show that the output power is 21 kW, which satisfies the design requirements. The results show that: a) reducing the pressure shell's thickness can improve the output power significantly; b) the system efficiency increases with the wire porosity, while the growth of system efficiency decreases when the porosity is higher than 80%, and system efficiency exhibits a linear relationship with the temperatures of the cold and hot sides; c) the system efficiency increases with the compression ratio; the compression ratio increases by 16.7% while the system efficiency increases by 42%. This study can provide valuable theoretical support for the design and analysis of FPSEs for space nuclear power reactors.

Total Hip Arthroplasty Outcomes in Patients with Gout: A Retrospective Analysis of Matched Large Cohorts

Zhichang Zhang,Hanzhi Yang,Zhiwen Xu,Jialun Chi,Quanjun Cui 대한정형외과학회 2024 Clinics in Orthopedic Surgery Vol.16 No.4

Background: Gout is the most prevalent form of inflammatory arthritis in the world. Total hip arthroplasty (THA) has emerged as a widely sought-after and highly effective surgical procedure for advanced hip diseases. However, there is a lack of research on the impact of gout on primary THA outcomes in large cohorts. This study aimed to address this gap by primarily investigating complications following THA in patients with or without gout. Methods: Patients with records of gout in the 2 years leading up to their primary THA and who also have at least 2 years of follow- up were identified using a national insurance database and compared to a 5:1 matched control. A total of 32,466 patients with gout and 161,514 patients without gout undergoing THA were identified. Multivariable logistic regression analyses were done for medical complications up to 90 days and surgical complications up to 2 years. In addition, 90-day emergency department (ED) visits and inpatient readmission were also documented. Results: Patients with gout demonstrated higher rates of medical complications including deep vein thrombosis, transfusion, acute kidney injury, and urinary tract infection than non-gout patients (p < 0.001). Gout patients also showed higher rates of pulmonary embolism (p = 0.017). Increased incidences of surgical complications were identified in gout patients, specifically wound complications and periprosthetic joint infection (p < 0.001). There was an increased risk of revision for gout patients up to 90 days (p = 0.003), 1 year (p = 0.027), and 2 years (p = 0.039). There was also an increased risk of dislocation for gout patients up to 90 days (p = 0.022) and 1 year (p = 0.047), but not at 2 years. No significant difference was observed in aseptic loosening or periprosthetic fracture. Additionally, gout patients also demonstrated a higher likelihood of 90-day ED visits and readmission (p < 0.001). Conclusions: Primary THA in gout patients is associated with increased risks of multiple medical and surgical complications. Our findings provide insights into the planning and expectation of THA for patients with gout. These insights have the potential to benefit the decision-making process for gout patients considering THA.

Pathogen-Imprinted Polymer Film Integrated probe/Ti₃C₂T_x MXenes Electrochemical Sensor for Highly Sensitive Determination of Listeria Monocytogenes

Xiaohua, Jiang,Zhiwen, Lv,Wenjie, Ding,Ying, Zhang,Feng, Lin The Korean Electrochemical Society 2022 Journal of electrochemical science and technology Vol.13 No.4

As one of the most hazardous and deadliest pathogens, Listeria monocytogenes (LM) posed various serious diseases to the human being, thus designing effective strategy for its detection is of great significance. In this work, by preparing Ti₃C₂T_x MXenes nanoribbon (Ti₃C₂T_xR) as carrier and selecting thionine (Th) acted simultaneously as signal probe and functional monomer, a LM pathogen-imprinted polymers (PIP) integrated probe electrochemical sensor was design to monitor LM for the first time, that was carried out through the electropolymerization of Th on the Ti₃C₂T_xR/GCE surface in the existence of LM. Upon eluting the templates from the LM imprinted cavities, the fabricated PIP/Ti₃C₂T_xR/GCE sensor can rebound LM cells effectively. By recording the peak current of Th as the response signal, it can be weakened when LM cell was re-bound to the LM imprinted cavity on PIP/Ti₃C₂T_xR/GCE, and the absolute values of peak current change increase with the increasement of LM concentrations. After optimizing three key parameters, a considerable low analytical limit (2 CFU mL^-1) and wide linearity (10-10⁸ CFU mL^-1) for LM were achieved. In addition, the experiments demonstrated that the PIP/Ti₃C₂T_xR sensor offers satisfactory selectivity, reproducibility and stability.

Marine Geo-environmental Disaster: Field Survey and In-situ Long-term Observation

( Yonggang Jia ),( Cong Hu ),( Zhiwen Sun ),( Hong Zhang ),( Hongxian Shan ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

Ocean exploitation has entered full ocean depth era. However, frequent marine geological disasters seriously restrict its development. Due to the complex marine engineering geology environment, in-situ observation has become an important means of submarine engineering survey. Based on the common types of marine geological disasters in marine engineering activities, this paper introduces the marine engineering geological survey and in-situ monitoring technology and its application from the perspective of marine engineering geological environment and dynamic action, so as to provide new ideas for the study of marine geological disasters in China.