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Ordinary piezoelectric force sensors are only capable of measuring dynamic forces but not static forces because of the charge leakage due to the finite resistance of piezoelectric materials and charge amplifiers. This paper presents a new strategy for in-process compensation of charge leakage for force measurement with wide spectrum from static to dynamic realized by piezoelectric force sensors. The compensation is in-process operated based on the concept of dynamic accumulation. In order to improve the measurement accuracy and long-term stability by the compensation, the zero offset generated by normalization, bias current and temperature drift are all theoretically analyzed and experimentally validated. Measurement experiments of four different types of force signals, which contain static, triangle, sinusoidal and random force signals acting on the piezoelectric force sensor, are conducted to validate the proposed strategy. In addition, the effect of different time constant of the piezoelectric sensor under different applied forces on the compensated results is analyzed. Performance tests contain accuracy, resolution, span and bandwidth have been conducted. It is validated that the proposed method has high sensitivity of sub-millinewton, long-term stability and wide spectrum from static signal to dynamic measurement capabilities, which would provide an effective and precise method for micro force measurement and control in ultra-precision machining, semiconductor industry and biomechanics fields.

Microalloying of Ti–6Al–4V alloy by Fe addition has attracted interest as a promising way to improve castability and comprehensive mechanical performance. The mission of this work is twofold by employing the experimental examination and the phenomenological analysis, (1) to investigate the effect of Fe addition on the microstructure features and mechanical properties of the Fe-containing Ti–6Al–4V (TC4-xF) alloys subjected to casting and homogenization treatment, and (2) to unveil the critical microstructure features in homogenization, hot-worked and aging treated alloys, respectively, that benefit the yield strength and the fracture toughness. Experimental observations evidence that the addition of 0.5 wt.% Fe is most effective in enhancing the tensile ductility and the mode I fracture toughness. Further Fe addition up to 0.7–0.9 wt.% results in plateau values of yield and ultimate strengths with some fluctuations. Phenomenological analyses screen out the microstructural strengthening and toughening determinants which exhibit distinct sensitivities on Fe content under different processing conditions. The solid solution strengthening is confirmed as the primary effect that governs the yield strength of the homogenization treated TC4-xF alloys, followed by the refined size of colony and α lamella, so does it for the hot-worked and the aging-treated alloys. The strengthening effect of Fe could be further promoted by hot-working but impaired by a prolonged annealing time or a lowered cooling rate. The type of crack propagation path and the α morphology are discerned to play their own leading roles in different cases to influence the performance of fracture toughness. A long crack propagation distance that traverses broad α/β lamellae embraces a high crack propagation resistance and gives rise to enhanced fracture toughness. The experimental results enrich the dataset of microstructure features and mechanical properties of Ti–6Al–4V relevant alloys. While upon the phenomenological analysis, the discovered microstructural strengthening and toughening factors provide deeper mechanism insights into the mechanical behaviors of Fe-modified Ti-6Al-4 V alloys and are of the technical importance to future machine-learning of microstructure-property relationship.

To investigate the clinical outcome and factors affecting the prognosis of endovascular mechanical thrombectomy of acute vertebrobasilar artery occlusion.Eighty-three patients with acute vertebrobasilar artery occlusion were treated with endovascular mechanical thrombectomy, and the recanalization rate, clinical outcomes at three months, modified DWI-PC-ASPECTS, and MRA-BATMAN scores were analyzed.Following acute mechanical thrombectomy, the TICI 2B-3 score was achieved in all patients (100%). At three-month evaluation, 56 (67.5%) patients had good prognosis with the mRS score of 0-2, including 13 (23.2%) patients who had arterial occlusion caused by emboli and 43 (76.8%) who had atherosclerotic stenosis. In analyzing factors affecting the prognosis, a significant difference (P 0.05) existed between patients with good (mRS 0-2) and poor (mRS 3-6) prognosis in the NIHSS (17.3 vs. 31.2, P = 0.000001), modified DWI-PC-ASPECTS (10.4 vs. 7.8, P = 0.021), and MRA-BATMAN (6.3 vs. 4.6, P = 0.003) scores. Univariate Logistic regression analysis demonstrated NIHS score ≥ 21, modified DWI-PC-ASPECTS score ≤ 8.5, and MRA-BATMAN score ≤ 6.5 to be the risk factors for poor prognosis. Multivariate Logistic regression analysis revealed NIHSS score ≥ 21 as an independent risk factor for poor prognosis.Endovascular mechanical thrombectomy is safe and effective in recanalizing occluded vertebrobasilar artery occlusion, and NIHS score ≥ 21, modified DWI-PC-ASPECTS score ≤ 8.5, and MRA-BATMAN score ≤ 6.5 are the risk factors for poor prognosis.

Duplex aging is one of the common heat treatments in titanium alloys. The microstructure introduced in the first-step aging has an effect on the growth/dissolution of α in the second-step aging. In the present work, a β + αacicular microstructure is preset in Ti–55531 (Ti-5Al-5Mo-5V-3Cr-1Zr wt%) alloy. The isochronal and isothermal phase transformation kinetics in the second-step aging is studied by combining the dilatometer test with microstructure characterization and local composition mapping. The phase transformations and corresponding temperature ranges are determined as β → αacicular [643–845 K] and αacicular → β [845–1130 K] by isochronal annealing. A TTT diagram for isothermal transformation kinetics is plotted based on the transformed phase fraction and reproduced by Johnson–Mehl–Avrami theory. The calculated kinetic curves are in good agreement with experiment ones. The C-shaped TTT curves verify the classical nucleation and growth of α in the second-step aging. In comparison with Ti–55531 alloy with preset β + αlath microstructure (in authors’ previous work), the α precipitation exhibits prolonged incubation period and slowed average transformation rate, which is evidenced by a right shift of C-curves for the α precipitation portion along the time axis. However, the C-curves of α dissolution show a left shift on the TTT diagram. The precipitation kinetics of α aciculae from dilatometry is synchronous with that obtained from the diffusion of Al detected in STEM mapping, while the diffusion of slow-diffusion elements lags behind the structural transformation. The TTT diagram and the dataset of microstructure features obtained in the present work can be employed to optimize processing in duplex aging.

The microstructure and mechanical properties of a newly developed Fe-microalloyed Ti&ndash, 6Al&ndash, 4V titanium alloy were investigated after different heat treatments. The volume fraction and the morphological features of the lamellar &alpha, phase had significant effects on the alloy&rsquo, s mechanical performance. A dataset showing the relationship between microstructural features and tensile strength, elongation, and fracture toughness was developed. A high aging temperature resulted in high plasticity and fracture toughness, but relatively low strength. The high strength favored the fine &alpha, and the slender &beta, The high aspect ratio of lamellar &alpha, led to high strength but low fracture toughness. The alloy with ~84 vol % &alpha, exhibited the highest strength and lowest fracture toughness because the area of its &alpha, /&beta, phase interface was the highest. Optimal comprehensive mechanical performance and heat-treatment procedures were thus obtained from the dataset. Optimal tensile strength, yield strength, elongation, and fracture toughness were 999 and 919 MPa, 10.4%, and 94.4 MPa&middot, m1/2, respectively.

The widely used Ti–6Al–4V (TC4) titanium alloy has been modified through the micro-alloying of Fe. The microstructural features and mechanical properties of the designed alloy, TC4F, are compared with other alloys in Ti–6Al–4V class by combining experimental characterizations and thermodynamic calculations. TC4F alloy not only maintains strength, hardness, and elongation similar to baseline TC4 but also exhibits improved fracture toughness comparable to TC4_ELI and even superior to TC4_DT under the heat-treated condition. It opens up a new cost-reducing way to enhance fracture toughness in place of controlling interstitial contents, showing potential in engineering applications. The discerned mechanisms indicate that the trace addition of Fe gives rise to composition redistribution between V and Fe in the β phase, boosts the lattice distortion and vibration, thereafter enhances Young's modulus and fracture toughness. It has been validated and verified by experiments, thermodynamic calculations, and Hahn-Rosenfield empirical research. The enhanced fracture toughness also benefits from the kinked β+α lamellar microstructure at crack tip as well as the improved fracture surface due to the Fe addition. The enlarged plastic zone, redirected crack propagation, and more dimples with even-distributed size additionally contribute to the improvement of fracture toughness., This work was supported by National Natural Science Foundation of China [Grants Nos. 51801101, 51701094, and 51602148], China Postdoctoral Science Foundation [Grant No. 2019M651812]. YC is acknowledged to the financial support from National Defense Basic Scientific Research Program of China [Grant No.JCKY2018414C020]. GX is acknowledged to the financial support from Natural Science Foundation of Jiangsu Province, China [Grant No. BK20171014].

The different β↔α phase transformation behaviors in Ti-55531 alloys with three types of preset microstructure were studied at isothermal conditions in the temperature range of 450–750°C. The dilatometry was employed to record the length change of the specimen. TTT diagrams for alloys with different microstructure were plotted based on the phase fractions of transformed α at different temperatures. With the help of Johnson–Mehl–Avrami theory, the calculated kinetic curves were in good agreement with experimental results. The β→secondary α transformation in the alloy with preset ‘β-quenched’ microstructure took place at higher nose temperature with a shorter incubation time in comparison with others, but exhibited lower steady transformation rate than that with preset ‘β+αequiaxed’ microstructure. With local composition analyses, the high nose temperature was interpreted by the difference in β stability and supersaturation. The alloy with preset ‘β+αequiaxed’ microstructure showed higher transformation rate than that with preset ‘β+αlamellar’ microstructure, which might be associated with the richness of defects. Keywords: Ti-55531, Phase transformation, Microstructure, Isothermal kinetics, TTT diagram, JMA theory

The α ↔ β phase transformation in dual-phase Ti–55531 alloy during the continuous heating was investigated by combining dilatometer test with microstructure characterization and local composition mapping. It was found that the α ↔ β phase transformation in individual temperature regions mainly involved either of two types of α phases, i.e. the lamellar α phase which forms during the continuous heating or the slab α phase raised in preliminary isothermal reaction. The corresponding transformation sequence was verified as β → α lamellae , α lamellae → β, and α slab → β. The pile-ups of alloying elements at the α/β interface were understood by either local equilibrium condition or differences among net diffusion fluxes of alloying elements. More important was that the growth and dissolution kinetics of both α phases were modeled and compared with experiments. With the calculations, the dissolution of slab α phase was demonstrated to follow the kinetics of planar interface without the Gibbs-Thomson effect. In contrast, the Gibbs-Thomson effect was proven to do contribution to lamellar α phase. It not only decreased the stability of α tip, such that the re-dissolution of lamellar α tips took place at 838 K below the equilibrium temperature, but also introduced a competition between the shrink of tips and thickening of broad face in α lamellae at 838–911 K. Moreover, the lengthening of lamellar α tips was proven to follow a kinetics controlled by a mixture of bulk and boundary diffusion, in comparison with the pure bulk diffusion of fastest Al governed the re-dissolution of both tips and broad faces.

A sophisticated understanding of phase transformations and microstructure evolution is crucial in mechanical property optimization for the newly developed low-cost Ti-35421 (Ti-3Al-5Mo-4Cr-2Zr-1Fe wt.%) titanium alloy. The phase transformations in dual-phase Ti-35421 were studied by experiments and thermo-kinetic modeling. The phase transformation reactions and temperature ranges were determined as &beta, &rarr, &alpha, lamellar [410&ndash, 660 &deg, C], &alpha, lamellar&rarr, &beta, [660&ndash, 740 &deg, lath&rarr, [740&ndash, 825 &deg, C]. The Gibbs-Thomson effect and multicomponent diffusivities were proven to be responsible for the distinguishing behaviors of growth and dissolution between two &alpha, phases. The aging temperature of 540 &deg, C was optimized based on calculations. It introduced a bimodal microstructure containing stubby &alpha, lamellae and &beta, matrix. The mechanical properties of bimodal Ti-35421 were tested and compared with baseline alloy Ti-B19 and other near-&beta, titanium alloys. The 540 &deg, C aged alloy exhibits an optimal combination of mechanical properties with tensile strength of 1313 MPa, yield strength of 1240 MPa, elongation of 8.62%, and fracture toughness of 75.8 MPa&middot, m1/2. The bimodal Ti-35421 shows comparable performance to Ti-B19 but has lower cost in raw materials and processing. The results also demonstrate that thermo-kinetic modeling can effectively be utilized in tailoring microstructure and enhancing mechanical properties.

Bimodal microstructures where globular &alpha, and acicular &alpha, phases are embedded in the &beta, matrix are commonly used in industry-relevant Ti-55531. To optimize the performance of Ti-55531 through heat treatment, it is crucial to understand and control the phase transformation in the as-received bimodal Ti-55531 as well as its microstructure evolution. In this work, the isochronal phase transformations and microstructure evolution in the bimodal Ti-55531 during the continuous heating were systematically studied by combining dilatometry, XRD phase analyses, and SEM observation. The &beta, &rarr, &alpha, transformation occurred at 678 K only with the acicular &alpha, When the temperature was higher than 788 K, &alpha, &beta, transformation took place in two separate stages (i.e., &alpha, acicular &rarr, and &alpha, globular &rarr, transformation). The dissolution of &alpha, globular occurred after the dissolution of &alpha, acicular was completed. Due to the difference in the chemical composition and interface curvature between &alpha, acicular and &alpha, globular, the average activation energy for &alpha, transformation was lower than that for the &alpha, transformation. The isochronal phase transformation and microstructure evolution during continuous heating in the present work could be used to optimize heat treatment procedures for desired mechanical properties.

Phase transformations of the β-quenched Ti-55531 alloy during continuous heating were studied by combining dilatometric measurement with phase analysis, microstructure observation, and local composition mapping. The corresponding transformation sequence can be verified as β → ω, β + ω → β + α, β → α, and α → β. By revisiting the individual phase transformations in the aforementioned transformation sequence, the variations of macro volume discovered in dilatometer test were reinterpreted based on three mechanisms, i.e., modification of crystallographic symmetry, thermodynamically partitioning, and diffusion kinetics. The interplay of different mechanisms was discussed for individual transformations, especially for the combinative partitioning and diffusion kinetic mechanisms of governed α ↔ β transformation. The pileups of Al atoms behind the growing α/β interface during β → α and of Mo atoms in the β side of α/β interface during α → β were observed and explained by incorporating the diffusion kinetic mechanism. All of these discoveries and discussions provided a deeper understanding of the phase transformations in Ti-55531 alloy.

The development of CALPHAD-type thermodynamic database for Ti or Zr based biomedical alloys has been spurred by the increased interest in efficiently tailoring an alloy composition to obtain high stability of β_bcc, low Young's modulus, and free of detrimental phases. However, the thermodynamic prediction is not adequate to be performed without the information of key sub-ternary Ti–Zr–Sn system. In present work, the thermodynamic assessment of Ti–Zr–Sn system is performed via a critical evaluation of phase equilibria and microstructure development in this ternary system. The partial isothermal sections at 1323 K and 1473 K with Sn content below 40 at. % are obtained by analyzing chemical compositions and crystal structures of individual phases in the annealed alloys. The composition homogeneity range of most phases is validated to favor a ternary extension paralleling to the Ti–Zr axis. Particularly, β_bcc and η phases (with the chemical composition (Ti, Zr)5Sn3+x) show complete solubility of Ti and Zr from Ti–Sn edge to Zr–Sn edge. With the database, negligible ternary solubility of Zr4Sn phase, microstructure development in the as-cast samples, and the controversial conclusions in literature are discussed. Most of the experimental findings, including equilibrium phase constitution, solidification sequence, DSC signals, projections of liquidus, are reproduced in a self-consistent way. The work moves towards the completeness of multi-component Ti/Zr thermodynamic database. It can be used for composition design of novel metastable β-type biomedical alloys.

Mg–Ga–Hg alloy is a new material with special electrochemical corrosion properties that make it ideal for use in seawater-activated battery anodes. The effects of microstructure and phase transformation on the electrochemical properties of the Mg – 4.1% Ga – 2.2% Hg alloy were studied and compared with Mg–Al system alloys. The results show that the Mg – 4.1% Ga – 2.2% Hg alloy, when used as an anode, has an appropriate corrosion potential in a half-cell test and superior electrochemical properties in a single cell assembled with CuCl. The Mg3Hg and Mg21Hg5Ga3 phases of the alloy influence its corrosion behaviour and provide a steady corrosion potential during the discharge process.

Located between the Tarim platform and Junggar massif, the West Tianshan intracontinental rift abuts against the China-Kazakhstan boundary in the west part, borders on the Yilianha-bierga late Paleozoic relic ocean basin and the South Tianshan late Paleozoic ocean basin respectively in the northeast separated by the Aibi Lake fault and in the southeast by the fault along the southern margin of the Yili massif. During the development and after the close of the West Tianshan intracontinental rifting in the Carboniferous-Permian period, a series of nonferrous and precious metal mineralizations occurred with the Au-Cu deposits being the most important. Isotopic chronologic study of representative deposits of different types shows that gold-copper mineralization in the West Tianshan intracontinental rift zone mainly happened during the middle-late Her-cynian Period, among which the Axi volcanic hydrothermal type gold deposit was formed during the Carboniferous with a fluid inclusion Rb-Sr isochron age of (339 ± 28) Ma; the Qiabukanzhuota quartzolite type gold deposit has a Rb-Sr isochron age of (312 ± 46) Ma; the Tawuerbieke porphyry type gold deposit has a Rb-Sr isochron age of (295 ± 16) Ma; the Jingbulak magmatic liquation Cu-Ni deposit and the Musizaote porphyry type Cu deposit have the forming ages of 300 Ma± and 250 Ma±, respectively. Analyses of crustal evolution and metallogenetic geological backgrounds of Au-Cu mineralizations in the studied area shows a close correlation with the rifting.

VMS deposits in Xinjiang, NW China are widespread in the Altay, Tianshan and West Kunlun orogenic belt, mainly formed during the Proterozoic rifting and Phanerozoic post-orogenic extension and are related to the bimodal volcanism. The VMS deposits are middle and small in scale. According to assemblages of metallogenetic elements, they can be divided into four types (Cu-Zn, Cu-S, Pb-Zn-Cu and Pb-Zn types) with the Cu-Zn and Pb-Zn types being the most important ones. Research of isotopic chronology shows that the VMS deposits in Xinjiang were formed during the Proterozoic, Ordovician, Deovonian, Carboniferous and Permian periods and usually underwent multi-stage mineralization, especially the large-sized deposits usually have post-volcanic superimposed mineralization by tectonomagmatic or metamorphic hydrothermal metal-logenic fluids.

Granitoids and related pegmatitic rare-metal deposits are widespread in China’s Altay region, they used to be considered as Hercynian rocks and mineral deposits. Reported here are the40Ar-39Ar ages of potassium-rich minerals (muscovite and microcline) in the Koktokay pegmatitic rare-metal orefield and whole-rock as well as quartz fluid-inclusion Rb-Sr isochron ages of granite and ores in the Shangkelan pegmatite rare-metal orefield. The ages indicate that there are Yanshanian Diagenetic Mineralization events happening in China’s Altay orogenic belt and that formation of the famous Koktokay No.3 pegmatitic rare-metal deposit endured about 30 Ma of magmatic crystallization differentiation.

On behalf of my coauthors, I thank Singh et al. for their comments regarding our study [2]. We agree they have raised valid questions. We believe that traction or tethering effect on the nerve roots due to spinal cord shift occurring after spinal canal decompression is the cause of postoperative C5 palsy [4]. The rationale for choosing this technique is to preserve ligamentous attachments and bony posterior elements as much as possible to control posterior shift of spinal cord after suitable decompression, instead of excessive decompression. The mean improvement ratio of neurologic function (Japanese Orthopaedic Association score) was 59% at last followup in this study. Because we did not have a control group for this study, it is unclear whether the suitable decompression of hemilaminectomy decreases the degree of cord function compared to excessive decompression of laminectomy. It is true that the hemilaminectomy approach may provide a relatively narrow exposure of the spinal canal, but does more decompression lead to a better clinical result? The surgical results for multilevel continuous/mixed cervical ossification of posterior longitudinal ligament involves various aspects, including neurological function and complications (especially C5 palsy and kyphosis) at short- and long-term followup. Previous studies [1, 3] reported that unilateral fixation had comparable efficacy to bilateral fixation in lumbar spinal fusion. Unilateral fixation is one of the remarkable novel ideas of this technique. We performed contralateral fixation because it was convenient to perform bone grafting on this side, and there was sufficient bone graft bed to afford adequate stabilization of the cervical spine. Because the cervical spine was not unstable, we tried unilateral fixation after multilevel hemilaminectomy and found it was enough for stabilization of the cervical spine. Our last followup indicated a spinal fusion rate of 100%. There were no instances of pseudoarthrosis, rod breakage, or pullout of screws. Fixation on both sides may be more rigid, but unilateral fixation can be acceptable if the approach stabilizes the cervical spine. Future research studying the long-term biomechanical outcomes of unilateral fixation is necessary. Thank you for highlighting some interesting issues relevant to this surgical technique.

Serum lipid peroxide (LPO) levels, superoxide dismutase (SOD) activity in peripheral blood erythrocytes, serum ANA, anti-dsDNA, and C3 were measured in 83 patients with systemic lupus erythematosus (SLE) and in 29 healthy controls. Compared to the controls, LPO levels were significantly increased in active SLE patients while SOD activity was markedly decreased. From the active phase to the inactive phase, a gradual decline in LPO levels and an increase in SOD activity were observed. There was a close correlation between LPO levels and disease activity or the parameters including ANA titers, anti-DNA titers, and C3 levels; a significant negative correlation was found between SOD activity and LPO levels or these parameters. Further, a marked difference in SOD activity was found in untreated active cases with and without nephritis. As the SLE patients improved, LPO levels gradually declined and SOD activity increased. The present study indicates that free radicals and resultantly formed lipid peroxide levels are higher in patients with SLE than those in normal persons, probably contributing to the production of autoantibodies, nephritis, and vasculitis of other organs, and that excessively generated free radicals may play an important role in the pathogenesis of SLE, which is possibly due to diminished SOD activity.