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Copyright of Journal of Harbin University of Science & Technology is the property of Journal of Harbin University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Accurate determination of platinum content in nickel-platinum alloy. It is an important index in material balance inspection and trade. In the past, diluted Inductively coupled plasma atomic emission spectroscopy were used, but the dilution process of this method is easy to introduce error. Yttrium internal standard measurement control. The sample was dissolved by hydrochloric acid and nitric acid, in 15% hydrochloric acid medium. The method of Accurate determination of platinum content in Ni-Pt alloy target by ICP-AES is established. the influencing factors, including the line selection, effect of matrix nickel, instrument determination conditions, were been experimented. The detection limits (µg/mL) of the method were 0.029 for (Pt 204.937), 0.046 for (Pt 299.797), 0.035 for (Pt 265.945). The determination levels of the platinum in the range from 1.00% to 15.00%. The standard recoveries are from 99.1% to 101.6%, RSD<1%. The method is accurate, fast and simple. The results were in good agreement with those obtained by Titrimetric determination. [ABSTRACT FROM AUTHOR]

The nickel content of nickel-based high-temperature alloy is between 50% and 70%, and the alloy contents of chromium, iron, cobalt, molybdenum, aluminum, titanium and tungsten are within 20%. A method of high resolution plasma mass spectrometry was established to determine the trace elements in nickel-based high-temperature alloy. According to the principle of large isotope abundance, small interference and high sensitivity, the isotopes and resolution of the elements to be measured were optimized, the interferences of most of the multi-atom and double-charged ions were effectively eliminated. The mass spectral interferences of matrix, compositions of alloy and dissolving acid on the trace elements were investigated. The appropriate internal standard of caesium was selected to overcome the matrix effect and reduce the signal drift. Chromium was extracted by methylisobutylone, the extraction efficiency reached up to 99.7%, which eliminated the mass spectral interference of principal component molybdenum in the nickel-based high-temperature alloy. The linear correlation coefficient of the calibration curve was greater than 0.999, and the method detection limit was between 0.002 1 and 0.074 μg/g. The trace elements in the reference material was analyzed, the relative standard deviation (RSD, n=6) was between 2.9% and 7.8%, and the measured value was very consistent with the standard value. This method is simple, fast, accurate and reliable, which can meet the requirement of trace elements determination in nickel-based high-temperature alloy. [ABSTRACT FROM AUTHOR]

BACKGROUND: During orthodontic treatment, the arch wire is an important part of the fixed appliance. The choice of arch wire largely determines the efficiency of tooth alignment. Among them, nickel-titanium alloys are widely used in fixed orthodontics due to their superelasticity and shape memory effect, and have become a research hotspot. OBJECTIVE: To review the development history and research progress of nickel titanium arch wires. METHODS: The literature search was performed in PubMed, Web of Science and CNKI databases. The Chinese and English keywords were “orthodontics, NiTi”. The articles were screened according to the inclusion and exclusion criteria. Finally, 77 articles were included for review. RESULTS AND CONCLUSION: Many scholars did researches to overcome the drawbacks of the NiTi arch wire, such as improving the composition, manufacturing process and surface modification. However, the current finished nickel-titanium arch wires still have various drawbacks, such as poor aesthetic properties of the arch wires; the release of nickel ions may cause allergic reactions, and the aesthetic coating is easy to fall off. Although there are commercial products of NiTi arch wire and are widely used in clinical orthodontic treatment, due to the complexity of orthodontic process, and many researchers are still in the laboratory stage; there is no ideal NiTi arch wire to meet the needs of all aspects of orthodontic clinical treatment. The improvement of various types of NiTi arch wire is an important supplement and development to the existing NiTi arch wire, and is expected to play a huge role in clinical applications in the future. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

According to the nonmagnetic requirement of smartphone components, electroplating and electroless plating of high-phosphorus Ni--P alloy successively on the surface of Ti--Cu alloy were studied. The process parameters for pretreatments (i.e. anodic electrodegreasing, cathodic electroetching, and nickel strike plating), electroplating and electroless plating of high-phosphorus Ni--P alloy, and sealing as post-treatment were optimized by orthogonal tests. The effect of mass fractions of phosphorus in the coating on its permeability was discussed. It was concluded that the mass fraction of phosphorus in coating should be at least 11% to meet the requirement of static permeability 1.003 H/m below. The continuous high-phosphorus Ni--P alloy electroplating and electroless plating process has been applied to practical production, and more than 99.8% of the products meet the quality requirements. [ABSTRACT FROM AUTHOR]

Copyright of Acta Scientiarum Naturalium Universitatis Sunyatseni / Zhongshan Daxue Xuebao is the property of Sun-Yat-Sen University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The variation law of potential and the formation process of zinc layer during the first and secondary zinc dipping were analyzed by electrochemical measurement and scanning electron microscopy. The effect of secondary zinc dipping on initial deposition behavior during alkaline electroless nickel plating was studied. The basic mechanism for secondary zinc dipping in improving the adhesion of nickel coating obtained subsequently was discussed. The results showed that titanium alloy underwent three stages during the first zinc dipping i.e. the dissolution of oxide film, the growth of thin zinc layer, and the dynamic balancing between the growth and dissolution of zinc layer, and a loose whisker-like zinc layer was formed. The general rule for film formation during the secondary zinc dipping was similar to that of the first zinc dipping, but it took less time to reach the dynamic growth--dissolution balance, and the zinc layer formed thereafter was more uniform and compact with a higher coverage. Secondary zinc dipping not only facilitates the quick formation of a complete and uniform nickel coating for the subsequent electroless nickel plating, but also improves the adhesion between titanium alloy and nickel coating. [ABSTRACT FROM AUTHOR]

Copyright of Bearing is the property of Bearing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective. To evaluate the clinical application effect of two nickel-titanium engine driven systems on moderate curved root canals. Methods. Ninety mesial root canals with moderate curvature of extracted human first mandibular permanent molar were randomly divided into three groups: M3 PRO Group, MTwo group and K group. The glide path was firstly preparedusing 10/04 file in M3 PRO group and MTwo group and 10 file in K group respectively. Then the preparation of root canals up to 25 was performed according to the instruction manual in each different group using standardized technique. All data including time required in glide path preparation, shaping preparation, total root canals preparation and changes of working length in root canal were recorded and analyzed statisticallyusing Analysis of Variance (ANOVA) and LSD-t tests (PResults. Root canal glide path preparation time: MTwo group showed significantly less preparation time while M3 PRO group exhibited significantly the longest preparation time. There was significant difference between MTwo group and M3 PRO group (P0.001). Root canal shaping preparation time: M3 PRO group showed significantly less preparation time while K group exhibited significantly the longest preparation time. Both MTwo group and M3 PRO group showed significantly less preparation time than K group (P0.004, P0.001), but there was no significant difference between MTwo group and M3 PRO group (P0.573). Total root canal preparation time: MTwo group showed the shortest time while K group exhibited the longest time. There were significant differences between MTwo group, M3 PRO group and K group (P0.004, P0.033), but no significant difference between MTwo group and M3 PRO group (P0.451). Changes of root canal working length: There were significant differences among the three groups (P0.037, P0.037, P0.000). M3 PRO group showed a minimal change while K group exhibited significant changes. Conclusion. MTwo nickel-titanium engine driven system with 10/04 file preform a high efficiency in glide path preparation, whilst M3 PRO nickel-titanium engine driven system show less changes in working length. Under the circumstancesthe total time required for root canal preparation is not significant, M3 PRO nickel-titanium engine driven system is more suifor root canal preparation in moderate curved root canals. [ABSTRACT FROM AUTHOR]

The microstructure， martensitic transformation and magnetic properties of Ni53Mn23.5Ga23.5-○xTi○x○(x=0， 2， 5 and 8)ferromagnetic shape memory alloys were studied to investigate the effects of different preparation methods and different Ti contents on the martensitic transformation and magnetic properties. The results show that when the Ti content increases， the grain size becomes finer， the martensitic transformation temperatures and martensitic transformation decrease， and the precipitate density increases where the appropriate amount of second-phase precipitations can facilitate to improve the high brittleness of the alloy. The EDS analysis indicates that in Ti doping alloys， the second-phase precipitation is rich in Ni and Ti constituents. The Ti addition decreases the saturation magnetization dramatically. The saturation magnetizations of Ti0 and Ti2 melt spun ribbons at the rotation speed of 900r/min are almost the same as those of the as-cast samples. However， the saturation magnetizations of the Ti5 and Ti8 melt spun samples are obviously higher than those of the as-cast ones， because the non-magnetic second-phase precipitations are suppressed in the melt spun process. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: A nickel titanium root canal file is the major instrument in root canal therapy, and its corrosion resistance is an important factor influencing its normal use. Therefore, it is of great clinicals ignificance to study the corrosion resistance of nickel titanium root canal files. OBJECTIVE: To assess the corrosion resistance and anti-fatigue breaking ability of M3 nickel titanium root canal files after rotating in NaOCl and autoclave sterilization. METHODS: Seventy-five M3 nickel titanium files were randomized into five groups (n=15 per group): A group, without any treatment, as a blank control; B group, rotating in 5.25% NaOCl for 10 minutes, repeated five times; C group, autoclave sterilization, repeated five times; D group, rotating in 5.25% NaOCl for 10 minutes, followed by autoclave sterilization, repeated five times; E group, rotating in 5.25% NaOCl 10 minutes, followed by autoclave sterilization, repeated 10 times. The anti-fatigue breaking ability and corrosion resistance (polarization resistance, electrochemical impedance and polarization curve) of M3 nickel titanium files after rotating in 5.25% NaOCl or/and autoclave sterilization were observed. RESULTS AND CONCLUSION: (1) Anti-fatigue fracture ability: there was no difference among groups in rotation number before the breakage. (2) Polarization resistance value: group E had the highest polarization resistance value which showed two orders of magnitude higher than that of group A; compared with group A, groups B and D showed a little increase in the polarization resistance value; and the polarization resistance values in groups A and C were of the same order of magnitude. (3) Electrochemical impedance: group E had the highest electrochemical impedance; compared with group A, the electrochemical impedance of groups B and D was improved; and the electrochemical impedance of groups C and A was of the same order of magnitude. (4) The polarization curve: all groups showed certain passivation characteristics. The passivation zone was unapparent in group A, became obvious in group E. There were similar polarization curves in the groups C and D. Group B showed relatively positive corrosion potential. In summary, both 5.25% sodium hypochlorite solution and autoclave sterilization have no influence on the anti-fatigue breaking ability of M3 nickel titanium files, but the combined use can enhance the corrosion resistance ability of M3 nickel titanium files. [ABSTRACT FROM AUTHOR]

According to the main experimental constitutive characteristics of the NiTi shape memory alloys ( SMAs) subjected to cyclic tensile loading, and in line with the constitutive relationship for the SMAs, an analytical approach and the corresponding numerical algorithm as well as the computational program were developed. The constitutive description is based on the mixture theory, employs the Voigt hypothesis, and takes into account the effects of forward and inverse martensitic transformation, reorientation deformation and plastic deformation. The pseudoelastic behavior of a NiTi SMA subjected to cyclic tensile loading and unloading was simulated. The comparison between the computed and experimental results shows that the main characteristics of the material under cyclic loading can be satisfactorily described, which demonstrates the validity of the constitutive model and the developed numerical program. [ABSTRACT FROM AUTHOR]

PURPOSE: To explore the mechanism of failure of ProTaper NiTi handfiles during root canal preparation. METHODS: A total of 2061 discarded ProTaper handfiles were collected after clinical use. The files were studied under stero-microscope to determine the type of defect. The fractured files were photographed digitally and the pictures were analyzed by software Image-Pro Plus to measure the distance from the break point to the tip. The data were statistically analyzed by using SPSS 11.0 software package. RESULTS: Plastic deformation was observed in 166 files (8.2%), and the types of defects included unwinding, winding flutes, and plastic bending. Instrument separation occurred in 581 files (28.2%), and the fracture rate was the highest in the F2 file group (41.7%). The Sx file group had the highest facture level, and the mean distance from the breakpoint to the file tip was (4.4±1.1) mm. CONCLUSIONS: For shaping files, especially at the apical level, the main cause of menial failure is overload of torque, whereas for finishing files, especially at the higher level, is cycle fatigue. Understanding the defect types of ProTaper handfiles is useful for avoiding file breakage during root canal therapy. [ABSTRACT FROM AUTHOR]

PURPOSE: To investigate the different incidence of postoperative pain and long-term follow--up curative effects in patients with chronic periapical periodontitis undergoing single visit root canal treatment by two kinds of canal preparation instruments system. METHODS: Ninety-eight permanent teeth with chronic periapical periodontitis were divided into two groups randomly. One group was prepared with nickel-titanium instruments, the other group was prepared with K files. After canal preparation, all the teeth underwent canal filling immediately. The different incidence of postoperative pain and long -term follow --up curative effects were recorded. Statistical analysis was carried out using SPSS13.0 software package. RESULTS: One week after treatment, the rate of serious symptom of periapical periodontitis in the Ni-Ti group was less than that in the K file group (P<0.05) . 18 months after treatment, the curative effect of two groups had no significant difference (P>0.05). CONCLUSIONS: Nickel-titanium instrument used in treatment of chronic periapical periodontitis lead to less serious postoperative reaction than K file instruments, but the same long-term follow-up curative effects as K file instruments. Nickel-titanium instruments system is worthy of wide application in patients with chronic periapical periodontitis undergoing single visit root canal treatment. [ABSTRACT FROM AUTHOR]

PURPOSE: To assess clinical application of Nickel-titanium (NiTi) rotary instruments Protaper in preparation of curved root canals. METHODS: 281 curved canals from 169 extracted molars were instrumented by Protaper rotary instruments using crown-down technique. An analysis was carried out regarding the relationship between the broken files and canal distribution, degree of curvature of canals, and the relationship between amount of the broken files and the duration was also included. SPSS18.0 software package was used for statistical analysis. RESULTS: A total of 43 kits files were used in the preparation of 281 curved root canals, and broken files often happened in canals with curvature of >30° and very complex canals. CONCLUSIONS: The fracture of NiTi instruments is closely related to the anatomy of the root canal. With the use of NiTi rotary instruments Protaper, curved root canals can be prepared effectively. Meanwhile, the problem of instrument separation should be prevented. [ABSTRACT FROM AUTHOR]

PURPOSE: To investigate the relationship of vertical root fracture (VRF) after root canal treatment with two different technique of root canal shaping and provide clinical reference. METHODS: 1702 teeth treated with root canal treatment during recent 2 years. All teeth were divided into two groups according to different techniques of root canal shaping: 643 teeth were prepared with NiTi rotary preparation technique (NRPT) and 1059 teeth were prepared with stainless steel hand K-files preparation technique (SSI:VF). The clinical symptoms and signs, radiological findings were estimated. The data was analyzed by SPSS 11.5 software package. RESULTS: There were 32 teeth with vertical root fracture, the VRF rate was 1.88%. The VRF rate in NRPT group was significantly higher than in SSPT group (P<0.01). The VRF rate with retreatment history in NRPT group was significantly higher than in SSPT group (P<0.01), but The VRF rate with post and core restoration in both NRPT and SSPT groups was not significantly different (P >0.05). CONCLUSIONS: NiTi rotary preparation technique (NRPT) was closely related with vertical root fracture (VRF). And the VRF risk would be even higher if the tooth underwent root canal retreatment case or a post-core was placed in the root canal. [ABSTRACT FROM AUTHOR]

PURPOSE: To analyze the shaping ability of three different rotary nickel-titanium instruments in curved molar canals. METHODS: Three groups of extracted molars that were balanced in terms of curvature were instrumented by Mtwo rotary ProTaper and Hero642 nickel-titanium systems, respectively. The standard digital radiographs were taken to record the profiles of root canals and the positions of the tips of the instruments. At last, the curvature degrees and the apical transportation indexes (ATI) pre- and post instrumentation were compared. All the data were analyzed with SAS6.12 software package. RESULTS: Two Hero642 instruments fractured during preparation and none of the Mtwo or rotary ProTaper instruments separated. The mean working time with Hero642 files was significantly longer than that with Mtwo or ProTaper instruments (P<0.0l). The change of curvature degree before and after instrumentation for three systems was statistically significant (P<0.05). And the difference of ATI for three systems was not significant (P>0.05). CONCLUSION: Mtwo and ProTaper systems tested in this study are effective in shaping curved molar canals in extracted teeth. [ABSTRACT FROM AUTHOR]

PURPOSE: To study the interappointment flare-ups after root canal preparation with Mtwo NiTi rotary system and explore the influence factors. METHODS: Ninty-seven pulp cases caused by caries or invisible cracks which consisted of 37 males and 60 females ,16 to 62 years old were selected and divided into 2 groups randomly. One group was treated with Mtwo NiTi rotary system while the other was treated with K file, the interappointment flare-ups after root canal preparation was compared between the 2 groups. The data were subjected to Mann-Whitney U test and X² test with SPSS13.0 software package. RESULTS: Less flare-ups occurred in the group of root canal preparation with NiTi rotary system, the difference was statistically significant (P=0.027). CONCLUSIONS: Root canal preparation with Mtwo NiTi rotary system could decrease the flare-ups after root canal therapy. Supported by Research Fund of Science and Technology Commission of Shanghai Municipality(08DZ2271100,08JC1414500) and Key Science and Technology Creative Project of Shanghai Municipality Education Commission(09ZZ116). [ABSTRACT FROM AUTHOR]