Effect of Different Cooling Rates in High Rheological Rate Forming Process on Mechanical Properties of Zr57Cu20Al10Ni8Ag5 Bulk Metallic Glass

Xiao‑Bo Mei,Bao‑Chuan Liu,Wei Jiang,Quan Xu,Qi‑Dong Zhang,Yu‑Bai Ma,Fang‑Qiu Zu 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.9

The influence of cooling rates on the mechanical properties of a Zr-based bulk metallic glass prepared with high rheologicalrate forming (HRRF) was investigated and compared with traditional suction cast methods. Amorphous samples of Zr57Cu-20Ni8Al10Ag5 were prepared in copper molds with different sizes in order to obtain different cooling rates for both HRRFand traditional cast methods. These specimens were subjected to compression experiments, including microhardness testing,X-ray diffraction testing and differential scanning calorimetry analysis. The results indicate that the plasticity of the samplesformed by HRRF are higher than that of the as-cast ones at the same cooling rates, while the microhardness manifests theopposite principle. As the cooling rate increases further, the difference in plasticity further increases between two methods,indicating that the plasticity of metallic glasses is more sensitive to cooling rates during the HRRF process. At the core ofthis phenomenon is the fact that HRRF methods can introduce more free volume into glasses than traditional cast methodswith an elevated cooling rate are able to.

Optimization of helicon wave current drive in HL-2M tokamak

Liu Hong Bo,Liu Guan Nan,Sun Ai Ping,Xiao Zheng Yao,Li Xin Xia 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.81 No.5

Helicon waves have been proposed for efcient of-axis current drive in high-performance tokamaks. The HL-2M tokamak will be operated with high plasma beta approaching to 훽N ∼ 4.0%, which provides a good platform to apply helicon wave system in the machine. Based on the helicon wave dispersion relation, efects of electron Landau damping and transit time magnetic pumping on wave absorption are analyzed according to the HL-2M plasma, and then, an optimized scheme of helicon wave parameter is proposed. The evolution of helicon wave electric feld and produced current drive are calculated by the AORSA full-wave code. It shows that current drive efciency of 100 kA/MW can be generally received in the machine. Moreover, the AORSA results are actively benchmarked with the ray-tracing code, and the results show a good consistency. Finally, the numerical convergence and the consumption of computation resources on grid point numbers in AORSA code are discussed.

Apoptosis-inducing effect and structural basis of Polygonatum cyrtonema Lectin and chemical modification properties on its mannose-binding sites

( Bo Liu ),( Xiao Chao Xu ),( Yan Cheng ),( Jian Huang ),( Yan Hong Liu ),( Zhen Liu ),( Ming Wei Min ),( He Jiao Bian ),( Jing Chen ),( Jin Ku Bao ) 생화학분자생물학회 2008 BMB Reports Vol.41 No.5

Enhancement of Butanol Tolerance and Butanol Yield in Clostridium acetobutylicum Mutant NT642 Obtained by Nitrogen Ion Beam Implantation

Xiao-Bo Liu,Qiu-Ya Gu,Xiao-Bin Yu,Wei Luo 한국미생물학회 2012 The journal of microbiology Vol.50 No.6

As a promising alternative biofuel, biobutanol can be produced through acetone/butanol/ethanol (ABE) fermentation. Currently, ABE fermentation is still a small-scale industry due to its low production and high input cost. Moreover, butanol toxicity to the Clostridium fermentation host limits the accumulation of butanol in the fermentation broth. The wild-type Clostridium acetobutylicum D64 can only produce about 13 g butanol/L and tolerates less than 2% (v/v) butanol. To improve the tolerance of C. acetobutylicum D64 for enhancing the production of butanol, nitrogen ion beam implantation was employed and finally five mutants with enhanced butanol tolerance were obtained. Among these, the most butanol tolerant mutant C. acetobutylicum NT642 can tolerate above 3% (v/v) butanol while the wide-type strain can only withstand 2% (v/v). In batch fermentation, the production of butanol and ABE yield of C. acetobutylicum NT642 was 15.4 g/L and 22.3 g/L, respectively, which were both higher than those of its parental strain and the other mutants using corn or cassava as substrate. Enhancing butanol tolerance is a great precondition for obtaining a hyperyield producer. Nitrogen ion beam implantation could be a promising biotechnology to improve butanol tolerance and production of the host strain C. acetobutylicum.

Preparation of Homogeneous Microstructure Pure Lead Metaniobate by Two-Step Sintering

Xiao-gang Zhao,Peng Liu,Bo Chao,Su Juan Liu,Ming Pang,Xiao-Ming Chen,Jian-Ping Zhou 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.1

The purpose of the present work is to obtain the Lead metaniobate ceramics with the orthorhombic phase via a two-step sintering method. The samples were first sintered at 1320°C for 10 min, and then sintered separately at 1260°C, 1220°C, and 1180°C for 4 h. All the ceramics show orthorhombic phase and homogeneous microstructure. It was found that the abnormal grain growth was restrained obviously.

Numerical simulation of helicon waves current drive in the HL-2M tokamak for the steady-state scenario

Liu Hong Bo,Li Xin Xia,Xiao Zheng Yao,Zhang Ding Zong,Sun Ai Ping 한국물리학회 2021 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.79 No.12

The helicon wave heating and current drive in the HL-2M tokamak for the steady-state scenario is studied numerically. Based on the theory of fast wave current drive proposed by Chiu, we analyze the characteristics of helicon waves damping for the HL-2M tokamak. For wave frequencies larger than 420 MHz, strong wave damping occurs, and electron Landau damping is dominant. Moreover, a strong wave absorption region associated with the dimensionless parameters βe and ξe that depend on the wave frequency is obtained. The helicon wave propagation and current drive are simulated using the GENRAY/CQL3D code. The results show that an off-axis current drive with profiles peak at ρ ∼ 0.4 can be generally received at a wave frequency f ∼ 500 MHz and the launched parallel refractive index n∕∕ = 3.8 and that the current drive efficiency reaches up to ∼140 kA/MW. A scan of n∕∕ showed that both the current drive profile peak and the generated current could be adjusted by changing the launched n∕∕ . Finally, a feasible scheme for the helicon wave off-axis current drive in the HL-2M tokamak is proposed.

Prediction of Educational Investment in China Based on Artificial Neural Networks and Grey Model GM (1,1)

Xiao Qianyin,Liu Bo 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.12

Recent years, as China is experiencing a rapid development, the educational investments are undergoing a sharp increase compared to past decades. Educational investment has become a crucial aspect that deeply influencing the future development of a country. What's more importantly, knowing the future investments of education is a crucial affair that decides the future tendency of related projects such as government management, cooperation investment and personnel training. Decision makers cannot make any effective decisions without knowing the future investments of education under all these circumstances. However, it is fairly difficult for people to obtain the predicted data of educational investments without the aid of mathematical and computational modeling. Therefore, in this article, we aim at presenting a series of solutions for the prediction of educational investment for China based on multiple linear regression (MLR), artificial neural networks (ANNs) and grey model GM (1,1). Multiple comparisons are made for deciding whether model should be used under different external conditions. Our research successfully shows that all these models are available for practical applications and scientists and other related people can choose their suitable models alternatively for the sake of making a better prediction under different circumstances.

Multiple Evaluation Models for Education Based on Artificial Neural Networks

Xiao Qianyin,Liu Bo 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.9

Teachers and students' performances are of great importance in education. However, how to evaluate teachers' works and students' academic levels are extremely difficult and complex because it contains various effects of weights that should be used to assess the achievements. Also, education workers often find it difficult to manipulate the large-scale data while evaluating the education works and students' performances. To address this problem, we used machine learning techniques to develop two groups of models for evaluating teachers and students' performances respectively. Using artificial neural networks (ANNs) can ensure the accuracy and fairness of the evaluation works. Our results successfully proved that general regression neural network (GRNN) model can effectively generate the robust responses to analyze different independent variables and give out correct results to distinguish different achievements done by teachers and students.

Diagnostic Value of ¹⁸F-FDG PET/CT in Comparison to Bone Scintigraphy, CT and ¹⁸F-FDG PET for the Detection of Bone Metastasis

Liu, Ning-Bo,Zhu, Lei,Li, Ming-Huan,Sun, Xiao-Rong,Hu, Man,Huo, Zong-Wei,Xu, Wen-Gui,Yu, Jin-Ming Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.6

Purpose: To evaluate the diagnostic value of $^{18}F$-FDG PET/CT for detection of bone metastasis in comparison with the efficacies of $^{18}F$-FDG PET/CT, CT, $^{18}F$-FDG PET and conventional planar bone scintigraphy in a series of cancer patients. Methods: Five hundred and thirty patients who underwent both $^{18}F$-FDG PET/CT and bone scintigraphy within 1 month were retrospectively analyzed. The skeletal system was classified into 10 anatomic segments and interpreted blindly and separately. For each modality, the sensitivity, specificity, accuracy, PPV and NPV were calculated and the results were statistically analyzed. Results: Bone metastases were confirmed in 117 patients with 459 positive segments. On patient-based analysis, the sensitivity, specificity, accuracy, PPV and NPV of $^{18}F$-FDG PET/CT were significantly higher than bone scintigraphy, CT and $^{18}F$-FDG PET (P<0.05). On segment-based analysis, the sensitivity of CT, bone scintigraphy, $^{18}F$-FDG PET and $^{18}F$-FDG PET/CT were 70.4%, 89.5%, 89.1% and 97.8%, respectively (P<0.05, compared with $^{18}F$-FDG PET/CT). The overall specificity and accuracy of the four modalities were 89.1%, 91.8%, 90.3%, 98.2% and 90.3%, 90.9%, 89.8%, 98.0%, respectively (P<0.05, compared with $^{18}F$-FDG PET/CT). The PPV and NPV were 89.8%, 87.6%, 85.6%, 97.2% and 85.6%, 93.2%, 92.8%, 98.6%, respectively. Three hundred and twelve lesions or segments were presented as lytic or sclerotic changes on CT images at the corresponding sites of increased $^{18}F$-FDG uptake. In lytic or mixed lesions, the sensitivity of $^{18}F$-FDG PET/CT and $^{18}F$-FDG PET were better than bone scintigraphy, while in osteoblastic lesions bone scintigraphy had a similar performance with $^{18}F$-FDG PET/CT but better than $^{18}F$-FDG PET alone. Conclusion: Our data allow the conclusion that $^{18}F$-FDG PET/CT is superior to planar bone scintigraphy, CT or $^{18}F$-FDG PET in detecting bone metastasis. $^{18}F$-FDG PET/CT may enhance our diagnosis of tumor bone metastasis and provide more information for cancer treatment.

Follow-Up of 58 Traumatic Carotid-Cavernous Fistulas after Endovascular Detachable-Balloon Embolization at a Single Center

Xiao-Quan Xu,Sheng Liu,Qing-Quan Zu,Lin-Bo Zhao,Jin-Guo Xia,Chun-Gao Zhou,Wei-Zhong Zhou,Hai-Bin Shi 대한신경과학회 2013 Journal of Clinical Neurology Vol.9 No.2

Background and Purpose This study evaluated the clinical value of detachable-balloon embolization for traumatic carotid-cavernous fistula (TCCF), focusing on the frequency, risk factors, and retreatment of recurrence. Methods Fifty-eight patients with TCCF underwent transarterial detachable-balloon embolization between October 2004 and March 2011. The clinical follow-up was performed every 3months until up to 3 years postprocedure. Each patient was placed in either the recurrence group or the nonrecurrence group according to whether a recurrence developed after the first procedure. The relevant factors including gender, fistula location, interval between trauma and the interventional procedure, blood flow in the carotid-cavernous fistula, number of balloons, and whether the internal carotid artery (ICA) was sacrificed were evaluated. Results All 58 TCCFs were successfully treated with transarterial balloon embolization, including 7 patients with ICA sacrifice. Recurrent fistulas occurred in seven patients during the follow-up period. Univariate analysis indicated that the interval between trauma and the interventional procedure (p=0.006) might be the main factor related to the recurrence of TCCF. The second treatments involved ICA sacrifice in two patients, fistula embolization with balloons in four patients, and placement of a covered stent in one patient. Conclusions Detachable balloons can still serve as the first-line treatment for TCCFs and recurrent TCCFs despite having a nonnegligible recurrence rate. Shortening the interval between trauma and the interventional procedure may reduce the risk of recurrence.