Preparation and properties of Al-Al2O3 metal ceramics via powder metallurgy methods

Jieguang Song,Xiuqin Wang,Lin Chen,Cailiang Pang,Jia Zhang,Weiguo Shi,Songlin Guo,Xianzhong Wang,Ruihua Wang 한양대학교 세라믹연구소 2018 Journal of Ceramic Processing Research Vol.19 No.1

Metal ceramics are outstanding new engineering materials that offer the advantages of both ceramics and metals. In this study,Al-Al2O3 metal ceramics were prepared through powder metallurgy methods, and the densification and properties of theprepared metal ceramics were investigated to gain insights into the preparation of high-performance cermet materials. Resultsrevealed that as the forming pressure was increased, the relative density of the ceramics increased, whereas their electricalresistivity decreased. The relative density increased with increasing sintering temperature up to 700 oC and decreased beyond700 oC, whereas the electrical resistivity exhibited an opposite trend. The relative density increased with increasing Al content,whereas the electrical resistivity displayed an opposite trend. Under optimal technological parameters of 700 oC sinteringtemperature, < 20MPa forming pressure, and 75 wt% Al content, Al-Al2O3 metal ceramics with a high relative density(97.52%) and a low electrical resistivity (101.34 Ω·m) were successfully prepared.

Effects of Root Pruning on Adventitious Root Formation, Enzyme Activities, and Hormone Levels in Paeonia suffruticosa ‘Fengdanbai’ Seedlings

Zheng Wang,Gege Su,Songlin He,Liyun Shi,Dan He,Wenqian Shang,Dajuan Yang 한국원예학회 2021 원예과학기술지 Vol.39 No.1

Root pruning during early root development can optimize the root structure of woody plants. To determine the effects of root pruning on tree peony (Paeonia suffruticosa), seedlings of the tree peony cultivar ‘Fengdanbai’ were subjected to varying degrees or different styles of root pruning. Various indexes were analyzed, including the anatomical structure of the root, root vitality, the activity levels of antioxidant enzymes, and the contents of endogenous hormones and their ratios. Comprehensive morphological observation showed that pruning freshly germinated roots that are 3 cm long by 1/3 (i.e., removing 1 cm) yielded the greatest rooting rate (90%), lateral root initiation (2.34 per seedling), and subsequent growth. Analysis of physiological and biochemical indicators during the critical rooting period (3-5 days after root pruning) showed that the levels of superoxide dismutase and abscisic acid (ABA) were decreased, while the oxidase activities of peroxidase, polyphenol oxidase, and indole acetate oxidase and the contents of the endogenous hormones indole acetic acid (IAA), gibberellin (GA3), and zeatin (ZT) were increased. IAA plays a key role in the process of adventitious root formation and the ratios of IAA/GA3, IAA/ABA, and IAA/ZT reflect endogenous hormone homeostasis during adventitious root formation. IAA/ABA and IAA/ZT showed higher values in the pruned roots compared to the control roots, which favor adventitious root induction and elongation. These results provide a basis for the study of adventitious root formation in tree peony.

Near-Duplication Document Detection Using Weight One Permutation Hashing

Xinpan Yuan,Songlin Wang,Xiaojun Deng 한국정보과학회 2019 Journal of Computing Science and Engineering Vol.13 No.2

As a standard algorithm for efficiently calculating set similarity, Minwise hashing is widely used to detect text similarity. The major drawback associated with Minwise hashing is expensive preprocessing. One permutation hashing (OPH) is proposed in order to reduce the number of random permutations. OPH divides the space Ω evenly into k bins, and selects the smallest nonzero value in each bin to re-index the selected elements. We propose a weight one permutation hashing (WOPH) by dividing the entire space Ω into k1 and k2 bins and sampling k1 and k2 in proportion to form a weighted kw. WOPH has a wider range of precision by expanding the proportion of w1 and w2 to different accuracy levels of the user. The variance of WOPH can be rapidly decreased first and then slowly decreased, although the final variance is the same as OPH with the same k. We combined the dynamic double filter with WOPH to reduce the calculation time by eliminating unnecessary comparison in advance. For example, for a large number of real data with low similarity accompanied by high threshold queries, the filter reduces the comparison of WOPH by 85%.

Reference Intervals for Thyroid-Associated Hormones and the Prevalence of Thyroid Diseases in the Chinese Population

Zou Yutong,Wang Danchen,Cheng Xinqi,Ma Chaochao,Lin Songbai,Hu Yingying,Yu Songlin,Xia Liangyu,Li Honglei,Yin Yicong,Liu Huaicheng,Zhang Dianxi,Zhang Kui,Lian Xiaolan,Xu Tengda,Qiu Ling 대한진단검사의학회 2021 Annals of Laboratory Medicine Vol.41 No.1

Background: Thyroid diseases are highly prevalent worldwide, but their diagnosis remains a challenge. We established reference intervals (RIs) for thyroid-associated hormones and evaluated the prevalence of thyroid diseases in China. Methods: After excluding outliers based on the results of ultrasound screening, thyroid antibody tests, and the Tukey method, the medical records of 20,303 euthyroid adults, who visited the Department of Health Care at Peking Union Medical College Hospital from January 2014 to December 2018, were analyzed. Thyroid-associated hormones were measured by the Siemens Advia Centaur XP analyzer. The RIs for thyroid-associated hormones were calculated according to the CLSI C28-A3 guidelines, and were compared with the RIs provided by Siemens. The prevalence of thyroid diseases over the five years was evaluated and compared using the chi-square test. Results: The RIs for thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), total thyroxine (TT4), and total triiodothyronine (TT3) were 0.71–4.92 mIU/L, 12.2–20.1 pmol/L, 3.9–6.0 pmol/L, 65.6–135.1 nmol/L, and 1.2–2.2 nmol/L, respectively. The RIs of all hormones except TT4 differed significantly between males and females. The RIs of TSH increased with increasing age. The prevalence of overt hypothyroidism, overt hyperthyroidism, subclinical hypothyroidism, and subclinical hyperthyroidism was 0.5% and 0.8%, 0.2% and 0.6%, 3.8% and 6.1%, and 3.3% and 4.7% in males and females, respectively, which differed from those provided by Siemens. Conclusions: Sex-specific RIs were established for thyroid-associated hormones, and the prevalence of thyroid diseases was determined in the Chinese population.

Experimental Research of Axial Compression Bearing Capacity on RC Columns Strengthened with Angle Steel and Self-Compacting Concrete

Qiang Hu,Songlin Jia,Huiqin Wu,Tongkuai Wang 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.1

An improved reinforced method used for concrete columns strengthened with angle steel and self-compacting concrete is proposed. Static loading experiments for sixteen specimens were carried out to study the infl uences of angle steels and batten plates spacing on axial compression bearing capacity of the concrete columns reinforced by the proposed method. The results show that axial compression bearing capacity increases signifi cantly; angle steels and concrete column can be eff ectively united to resist the loads from superstructure because of self-compacting concrete; the increase of area of angle steel and the decrease of batten plates spacing can eff ectively increase axial compression bearing capacity of the reinforced columns.

SSF: Sentence Similar Function Based on word2vector Similar Elements

Xinpan Yuan,Songlin Wang,Lanjun Wan,Chengyuan Zhang 한국정보처리학회 2019 Journal of information processing systems Vol.15 No.6

In this paper, to improve the accuracy of long sentence similarity calculation, we proposed a sentence similaritycalculation method based on a system similarity function. The algorithm uses word2vector as the systemelements to calculate the sentence similarity. The higher accuracy of our algorithm is derived from twocharacteristics: one is the negative effect of penalty item, and the other is that sentence similar function (SSF)based on word2vector similar elements doesn’t satisfy the exchange rule. In later studies, we found the timecomplexity of our algorithm depends on the process of calculating similar elements, so we build an index ofpotentially similar elements when training the word vector process. Finally, the experimental results show thatour algorithm has higher accuracy than the word mover’s distance (WMD), and has the least query time ofthree calculation methods of SSF.

SSF: Sentence Similar Function Based on word2vector Similar Elements

Yuan, Xinpan,Wang, Songlin,Wan, Lanjun,Zhang, Chengyuan Korea Information Processing Society 2019 Journal of information processing systems Vol.15 No.6

In this paper, to improve the accuracy of long sentence similarity calculation, we proposed a sentence similarity calculation method based on a system similarity function. The algorithm uses word2vector as the system elements to calculate the sentence similarity. The higher accuracy of our algorithm is derived from two characteristics: one is the negative effect of penalty item, and the other is that sentence similar function (SSF) based on word2vector similar elements doesn't satisfy the exchange rule. In later studies, we found the time complexity of our algorithm depends on the process of calculating similar elements, so we build an index of potentially similar elements when training the word vector process. Finally, the experimental results show that our algorithm has higher accuracy than the word mover's distance (WMD), and has the least query time of three calculation methods of SSF.

Influence of Nocturnal Supplemental Lighting and Different Irrigation Regimes on Vase Life and Vase Performance of the Hybrid Rose ‘Charming Black’

Liyun Shi,Songlin He,Zheng Wang,Wan Soon Kim 한국원예학회 2021 원예과학기술지 Vol.39 No.1

Preharvest conditions, including photoperiod and irrigation regime, affect the keeping quality of long stem roses (Rosa x hybrida). Rose plants of the cultivar ‘Charming Black’ were subjected to four different treatments to investigate how nocturnal supplemental lighting and different irrigation regimes influence post-harvest performance. Vase life, ornamental quality, water balance, petal color, vacuolar pH, soluble sugar content, and soluble protein content were investigated in this study. Treatment with nocturnal supplemental lighting extended the vase life and increased the daily ornamental value in cut roses. In addition, flowers grown under nocturnal supplemental lighting and without irrigation had significantly improved flower color and ornamental value and the highest values for soluble sugar content and soluble protein content. Withholding irrigation under supplemental lighting promoted maintenance of the water balance, which prolonged the vase life of the cut flowers. This study illustrates that supplemental lighting is helpful in extending the vase life of cut roses and that a non-irrigation regime under supplemental lighting results in the most promising physiological and biochemical responses.

Sintering densification and properties of Al2O3/Al cermet materials via powder metallurgy method

Jieguang Song,Yue Liu,Cailiang Pang,Jia Zhang,Lin Chen,Xiling Zhang,Songlin Guo,Xianzhong Wang,Ruihua Wang,Aixia Chen 한양대학교 세라믹연구소 2018 Journal of Ceramic Processing Research Vol.19 No.2

Cermet materials are important new engineering materials with combined advantages of ceramics and metals. In this study,Al2O3/Al cermet materials were prepared through powder metallurgy. The effect of sintering technology on the properties ofAl2O3/Al cermet materials was analyzed as basis for preparing high-performance cermet materials. Results showed that whenthe sintering temperature was increased from 700 oC to 1000 oC under holding time for 1 h, the densification degree and hardnessof Al2O3/Al cermet materials decreased and the electric resistivity increased. In the microstructure of Al2O3/Al cermet materials,Al particles were larger and continuously distributed, whereas the Al2O3 particles were smaller and discontinuously distributed. When the holding time was increased under sintering temperature of 700 oC, the densification degree and hardness of Al2O3/Alcermet materials also increased, and the electric resistivity decreased. When 25 wt% Al2O3/Al cermet materials were sintered at700 oC for 3 h, the densification degree was higher, with hardness of 2203 HV and electric resistivity of 0.0159 Ω • m.

The effect of the sintering temperature on the properties of porous YAG ceramics

Jieguang Song,Lin Chen,Cailiang Pang,Jia Zhang,Weiguo Shi,Songlin Guo,Xianzhong Wang,Minghan Xub 한양대학교 세라믹연구소 2018 Journal of Ceramic Processing Research Vol.19 No.1

Pure yttrium aluminum garnet (YAG) powders and the porous YAG ceramics were prepared via co-precipitation method andusing vacuum sintering technology, respectively. Through an analysis and discussion, porous YAG ceramics, with ahomogeneous and regular pore microstructure, a pore size of about 5 μm, regular crystalline particles, showing intergranularfracture, were sintered at 1500 oC. Porous YAG ceramics, with a homogeneous and regular pore microstructure, a pore sizefor about 2-5 μm, crystals with a rod-shape or acicular structure, showing intergranular fracture and intracrystalline fracture,were sintered at 1550 oC. Porous YAG ceramics, with an extension pore microstructure, a crystalline laminate structure,showing intracrystalline fracture, were sintered at 1600 oC. With an increase in the sintering temperature, the porosity isdecreased gradually and the energy consumption is increased. The best sintering temperature for porous YAG ceramics wasdecided to be 1550 oC through considering the performance price ratio among the porosity, the mechanical properties and theenergy consumption.