Microstructure and Mechanical Properties of Cold Drawn Ti–Nb–Ta–Zr–O Wires for Orthodontic Applications

Wei‑dong Zhang,Junye Ren,Bin Liu,Yong Liu,Zhenggang Wu,Jingwen Qiu 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.7

Ti–36Nb–2Ta–3Zr–0.35O (TNTZO) alloy is an excellent candidate for biomedical applications. In this study, a new methodcombining cold-swaging and cold-drawing was used to fabricate the TNTZO alloy wires with 0.3 mm diameter for orthodonticapplications. The microstructure and mechanical properties of cold-drawn and annealed TNTZO wires (referred toas TNTZO0.3and TNTZO0.3(HT), respectively) were investigated. The results show that the microstructure of cold drawnTNTZO0.3consists of main-sized elongated grains with 70 nm width. After annealing at 700 °C for 5 min, the microstructureof TNTZO0.3(HT) wires becomes equiaxial with a grain size of ~ 5 μm. The cold drawn TNTZO0.3wires exhibit improvedmechanical properties, higher tensile strength (about 1000 MPa) and similar elastic modulus (69 GPa), compared to annealedTNTZO0.3(HT) wires. Besides, TNTZO0.3has higher creep resistance and lower stress exponent (around 2), compared to Tiwires and TC4 wires with the same diameter. These results prove that TNTZO0.3wires have most of the ideal characteristicsof orthodontic wires.

Expression in Escherichia coli and Purification of Folded rDer p 20, the Arginine Kinase From Dermatophagoides pteronyssinus: A Possible Biomarker for Allergic Asthma

Sarzsinszky Eszter,Lupinek Christian,Vrtala Susanne,Huang Huey-Jy,Hofer Gerhard,Keller Walter,Chen Kuan-Wei,Panaitescu Carmen Bunu,Resch-Marat Yvonne,Zieglmayer Petra,Zieglmayer René,Lemell Patrick,Ho 대한천식알레르기학회 2021 Allergy, Asthma & Immunology Research Vol.13 No.1

Arginine kinase (AK) was first identified as an allergen in the Indian-meal moth and subsequently shown to occur as allergen in various invertebrates and shellfish. The cDNA coding for AK from the house dust mite (HDM) species Dermatophagoides pteronyssinus, Der p 20, has been isolated, but no recombinant Der p 20 (rDer p 20) allergen has been produced and characterized so far. We report the expression of Der p 20 as recombinant protein in Escherichia coli. rDer p 20 was purified and shown to be a monomeric, folded protein by size exclusion chromatography and circular dichroism spectroscopy, respectively. Using AK-specific antibodies, Der p 20 was found to occur mainly in HDM bodies, but not in fecal particles. Thirty percent of clinically well-characterized HDM allergic patients (n = 98) whose immunoglobulin E (IgE) reactivity profiles had been determined with an extensive panel of purified HDM allergens (Der f 1, 2; Der p 1, 2, 4, 5, 7, 10, 11, 14, 15, 18, 21, 23 and 37) showed IgE reactivity to Der p 20. IgE reactivity to Der p 20 was more frequently associated with lung symptoms. AKs were detected in several invertebrates with specific antibodies and Der p 20 showed IgE cross-reactivity with AK from shrimp (Litopenaeus vannamei). Thus, Der p 20 is a cross-reactive HDM allergen and may serve as a diagnostic marker for HDM-induced lung symptoms such as asthma.

Taxonomy of the genus Laena from Yunnan in China, with description of eight new species (Coleoptera: Tenebrionidae: Lagriinae)

Wei Zhonghua,Zhao Xiaolin,Ren Guodong 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.3

Eight new species of the genus Laena Dejean, 1821 (subfamily Lagriinae, tribe Laenini) from Yunnan Province of China were described and illustrated: L. acutidentata Wei & Ren, sp. nov., L. brevicarina Wei & Ren, sp. nov., L. dongchuana Zhao & Ren, sp. nov., L. glabridentipa Wei & Ren, sp. nov., L. nuda Zhao & Ren, sp. nov., L. raropuncta Wei & Ren, sp. nov., L. rugulosa Wei & Ren, sp. nov. and L. spinicla Wei & Ren, sp. nov.. Illus trations and a key to the known Laena species from Yunnan Province are provided.

Taxonomic study of the genus Laena from Sichuan in China, with description of four new species (Coleoptera: Tenebrionidae)

Wei Zhonghua,Zhao Xiaolin,Ren Guodong 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.2

The genus Laena Dejean, 1821 belongs to the subfamily Lagriinae, tribe Laenini. Four new species of this genus are described and illustrated from Sichuan under the following name: Laena ceratina Wei & Ren, sp. nov., Laena edentata Zhao & Ren, sp. nov. (from Sichuan and Qinghai), Laena latitarsia Wei & Ren, sp. nov. (from Sichuan and Yunnan) and Laena sufflofemora Wei & Ren, sp. nov.. A key to the known Laena species from Sichuan is provided.

Empirical formulas to estimate cable tension by cable fundamental frequency

Ren, Wei-Xin,Chen, Gang,Hu, Wei-Hua Techno-Press 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.20 No.3

The cable tension plays an important role in the construction, assessment and long-term health monitoring of cable structures. The cable vibration equation is nonlinear if cable sag and bending stiffness are included. The engineering implementation of a vibration-based cable tension evaluation is mostly carried out by the simple taut string theory. However, the simple theory may cause unacceptable errors in many applications since the cable sag and bending stiffness are ignored. From the practical point of view, it is necessary to have empirical formulas if they are simple and yet accurate. Based on the solutions by means of energy method and fitting the exact solutions of cable vibration equations where the cable sag and bending stiffness are respectively taken into account, the empirical formulas are proposed in the paper to estimate cable tension based on the cable fundamental frequency only. The applicability of the proposed formulas is verified by comparing the results with those reported in the literatures and with the experimental results carried out on the stay cables in the laboratory. The proposed formulas are straightforward and they are convenient for practical engineers to fast estimate the cable tension by the cable fundamental frequency.

Test Results and Nonlinear Analysis of RC T-beams Strengthened by Bonded Steel Plates

Wei Ren,Lesley H. Sneed,Yiting Gai,Xin Kang 한국콘크리트학회 2015 International Journal of Concrete Structures and M Vol.9 No.2

This paper describes the test results and nonlinear analysis of reinforced concrete T-beams strengthened by bonded steel plates under increasing static loading conditions. The first part of this paper discusses the flexural tests on five T-beams, including the test model design (based on similarity principles), test programs, and test procedure. The second part discusses the nonlinear numerical analysis of the strengthened beams, in which a concrete damage plasticity model and a cohesive behavior were adopted. The numerical analysis results are compared with experimental data and show good agreement. The area of bonded steel plate and the anchor bolt spacing were found to have an impact on the cracking load, yield load, and ultimate load. An increase in the area of steel plate and a reduction of the anchor spacing could significantly improve the cracking and ultimate loads and decrease the damage of the beam.

Output-only modal parameter identification of civil engineering structures

Ren, Wei-Xin,Zong, Zhou-Hong Techno-Press 2004 Structural Engineering and Mechanics, An Int'l Jou Vol.17 No.3

The ambient vibration measurement is a kind of output data-only dynamic testing where the traffics and winds are used as agents responsible for natural or environmental excitation. Therefore an experimental modal analysis procedure for ambient vibration testing will need to base itself on output-only data. The modal analysis involving output-only measurements presents a challenge that requires the use of special modal identification technique, which can deal with very small magnitude of ambient vibration contaminated by noise. Two complementary modal analysis methods are implemented. They are rather simple peak picking (PP) method in frequency domain and more advanced stochastic subspace identification (SSI) method in time domain. This paper presents the application of ambient vibration testing and experimental modal analysis on large civil engineering structures. A 15 storey reinforced concrete shear core building and a concrete filled steel tubular arch bridge have been chosen as two case studies. The results have shown that both techniques can identify the frequencies effectively. The stochastic subspace identification technique can detect frequencies that may possibly be missed by the peak picking method and gives a more reasonable mode shapes in most cases.

Output-only modal parameter identification of civil engineering structures

Wei-Xin Ren,Zhou-Hong Zong 국제구조공학회 2004 Structural Engineering and Mechanics, An Int'l Jou Vol.17 No.3-4

The ambient vibration measurement is a kind of output data-only dynamic testing where the traffics and winds are used as agents responsible for natural or environmental excitation. Therefore an experimental modal analysis procedure for ambient vibration testing will need to base itself on output-only data. The modal analysis involving output-only measurements presents a challenge that requires the use of special modal identification technique, which can deal with very small magnitude of ambient vibration contaminated by noise. Two complementary modal analysis methods are implemented. They are rather simple peak picking (PP) method in frequency domain and more advanced stochastic subspace identification (SSI) method in time domain. This paper presents the application of ambient vibration testing and experimental modal analysis on large civil engineering structures. A 15 storey reinforced concrete shear core building and a concrete filled steel tubular arch bridge have been chosen as two case studies. The results have shown that both techniques can identify the frequencies effectively. The stochastic subspace identification technique can detect frequencies that may possibly be missed by the peak picking method and gives a more reasonable mode shapes in most cases.

Statistical Optimization of Medium Components for Milk-Clotting Enzyme Production by Bacillus amyloliquefaciens D4 Using Wheat Bran-an Agro-Industry Waste

( Wei Bing Zhang ),( Xiao Ling He ),( Hong Na Liu ),( Hui Yuan Guo ),( Fa Zheng Ren ),( Wei Dong Gao ),( Peng Cheng Wen ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.8

In this paper, two statistical methods were applied to optimize medium components to improve the production of the milk-clotting enzyme by Bacillus amyloliquefaciens D4. First, wheat bran juice, skim milk powder, and Na2HPO4 were shown to have significant effects on D4 enzyme production using the Plackett?Burman experimental design. Subsequently, an optimal medium was obtained using the Box?Behnken method, which consisted of 3.31 g/l of skim milk powder, 5.0 g/l of sucrose, 0.1 g/l of FeSO4?7H2O, 0.1 g/l of MgSO4?7H2O, 0.1 g/l of MnSO4?2H2O, 0.1 g/l of ZnSO4?7H2O, 1.52 g/l of Na2HPO4, and 172.45 g/l of wheat bran juice. With this optimal medium, the milk-clotting enzyme production was remarkably enhanced. The milk-clotting enzyme activity reached 3,326.7 SU/ml after incubation of 48 h, which was 1.76-fold higher than that of the basic medium, showing that the Plackett?Burman design and Box?Behnken response surface method are effective to optimize medium components, and B. amyloliquefaciens D4 possessed a high rennet-producing capacity in the optimal medium.

Nonlinear vibration of hybrid composite plates on elastic foundations

Wei-Ren Chen,Chun-Sheng Chen,Szu-Ying Yu 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.37 No.4

In this paper, nonlinear partial differential equations of motion for a hybrid composite plate subjected to initial stresses on elastic foundations are established to investigate its nonlinear vibration behavior. Pasternak foundation and Winkler foundations are used to represent the plate-foundation interaction. The initial stress is taken to be a combination of pure bending stress plus an extensional stress in the example problems. The governing equations of motion are reduced to the time-dependent ordinary differential equations by the Galerkin's method. Then, the Runge-Kutta method is used to evaluate the nonlinear vibration frequency and frequency ratio of hybrid composite plates. The nonlinear vibration behavior is affected by foundation stiffness, initial stress, vibration amplitude and the thickness ratio of layer. The effects of various parameters on the nonlinear vibration of hybrid laminated plate are investigated and discussed.