Effect of heat treatment on microstructure,mechanical and tribological properties of in-situ (TiC+TiB)/TC4 composites by casting

To enhance the performance of in-situ synthesized 6vol.%(Ti C+Ti B)/TC4 titanium matrix composites fabricated by casting,a variety of heat treatment processes were carried out.Upon conducting microstructure observations following various heat treatments,it was found that the composites exhibit a basketweave microstructure,consisting of an α phase and a transformed β phase.The sizes of(α+β) phases were found to be refined to varying degrees after the heat treatment processes,while the morphology of Ti B remains largely unchanged and Ti C becomes granulated.Compressive testing revealed that all composites subjected to different heat treatments demonstrate a notable increase in ultimate compressive strength as well as a slight improvement in plasticity compared to the as-cast state.The results of the tribological performance test indicated that the heat-treated composites exhibit lower average friction coefficient,specific wear rate,and worn surface roughness compared to the as-cast composite.Among the heat treatment processes studied,the composite solution heated at 1,150 °C/1 h followed by air cooling,then 950 °C/1 h followed by air cooling,and finally 500 °C/4 h followed by air cooling,demonstrates the highest levels of hardness,compressive strength,and wear resistance.These improvements are attributed to the combined effects of solid solution strengthening,grain refinement,and the pinning of dislocation slip.

Application of contrast-enhanced ultrasound after livertransplantation:Current status and perspectives

Liver transplantation is an effective treatment for patients with end-stage liver disease. Accurate imaging evaluation of the transplanted patient is critical for ensuring that the limited donor liver is functioning appropriately. Ultrasound contrast agents(UCAs), in combination with contrastspecific imaging techniques, are increasingly accepted in clinical use for the assessment of the hepatic vasculature, bile ducts and liver parenchyma in pre-, intra- and posttransplant patients. We describe UCAs, their technical requirements, the recommended clinical indications, image interpretation and the limitations for contrastenhanced ultrasound applications in liver transplantation.

Perithyroidal hemorrhage caused by hydrodissection during radiofrequency ablation for benign thyroid nodules:Two case reports

BACKGROUND Hydrodissection is a widely used technique during radiofrequency ablation(RFA)for benign thyroid nodules.Although it could effectively avoid thermal injury to the surrounding critical structures and achieve complete treatment,routine operation of the remaining needle could cause perithyroidal hemorrhage.In this report,we present 2 cases of perithyroidal hemorrhage during RFA caused by a hydrodissection needle,which have not been reported before.CASE SUMMARY A 21-year-old female and a 45-year-old male were admitted for RFA for benign thyroid nodules.Considering that their nodules were adjacent to the recurrent laryngeal nerve,the needle used for hydrodissection was placed and remained between the dorsal capsule of the lateral lobe and the recurrent laryngeal nerve.During the procedure,active bleeding near the needle appeared on ultrasonography(US).Although moderate pressure was quickly applied to the neck for several minutes,contrast-enhanced US(CEUS)still showed an active hemorrhage.A radiofrequency electrode was placed at the bleeding point under the guidance of CEUS to stop the bleeding,and the procedure was finally confirmed to be successful by CEUS,without other complications.CONCLUSION Hydrodissection during RFA of benign thyroid nodules was associated with a risk of perithyroidal hemorrhage.The timely recognition of this acute hemorrhage could help in the timely control of the bleeding,and CEUS-guided ablation of the bleeding point could be useful.

Correction and verification of HL-2A Tokamak Bonner sphere spectrometer in monoenergetic neutron fields from 100 keV to 5 MeV

A real-time Bonner sphere spectrometer(BSS)has been developed for spectral neutron measurements with the HL-2A Tokamak.To correct and verify the accuracy of the neutron spectrum from the BSS,the BSS system was calibrated using monoenergetic neutron beams in the energy range of 100 keV–5 MeV.The response function of the BSS was corrected based on the calibration results,and the corrected BSS system was verified by unfolding monoenergetic neutron spectra.Fusion neutron spectra on the HL-2A have been obtained from the calibrated BSS system for the first time.

Development of the real-time double-ring fusion neutron time-of-flight spectrometer system at HL-2M

A real-time double-ring neutron time-of-flight(TOFII) spectrometer system has been proposed to achieve plasma diagnosis on HL-2M tokamak with a relatively high count rate and sufficient energy resolution.The TOFII system is in its development stage,and this work describes its characteristics in terms of design principle,system structure,electronic system design,preliminary tests,and neutron transport simulation.The preliminary test results illustrate that the TOFII system can demonstrate the realtime dynamic spectrum every 10 ms.The results also show that based on the support vector machine method,the n-γ discrimination algorithm achieves the discrimination accuracy of 99.1%with a figure of merit of 1.30,and the intrinsic timing resolution of the system is within 0.3%.The simulated flight time spectrums from 1 to 5 MeV are obtained through the Monte Carlo tool Geant4,which also provide the reasonable results.The TOFII system will then be calibrated on mono-energetic neutron sources for further verification.

Sacral chondroblastoma — a rare location, a rare pathology: A case report and review of literature

BACKGROUND Chondroblastoma(CB)is an intermediate tumor of cartilage origin.CB involving the sacrum is a very rare pathology.CASE SUMMARY A 17-year-old male with sacral CB was diagnosed as CB during the first surgery,and 18 mo later,the tumor recurred and a second surgery was performed with the same pathology result of CB.CONCLUSION We recommend complete removal of the tumor in a timely manner,provided that surgical conditions are met.At the same time,other diseases should be carefully differentiated in terms of imaging or pathological features so as to avoid erroneous diagnostic conclusions.

High-temperature oxidation behavior of a cast Ti-47.5Al-2.5V-1.0Cr-0.2Zr alloy

The oxidation behavior of the Ti-47.5Al-2.5V-1.0Cr-0.2Zr alloy at 900℃ was investigated at different oxidation times(5,20,60 and 100 h).The results show that the total weight gain of the alloy after 100 h at 900℃ oxidation is 9.1 g·m^(-2),and the oxidation rate decreases with oxidation time.The oxides on the alloy surface are mainly TiO_(2) and Al_(2)O_(3).At the beginning of oxidation(5 h),the oxide film is relatively complete,thin,and the interface between the oxide layer and the matrix is virtually flat.At the end of oxidation(100 h),the thickness of the oxide film is expanded,cracking and spalling occur,and the spalling form is intra-film spalling.At the same time,oxygen is mainly distributed in the oxide film and the oxygen content in the alloy substrate is reduced,confirming that the TiAl alloy has a certain oxidation stability at 900℃.From the outer surface of the oxide layer to the matrix,the TiO_(2) content increases and the Al_(2)O_(3) content decreases.Oxidation proceeds to completion in this system via the dissolution and diffusion of O atom.

Complications Following Radiofrequency Ablation of Benign Thyroid Nodules： A Systematic Review

Objective： This systematic review examined whether radiofrequency ablation （RFA） is a sate treatment modality for benign thyroid nodules （BTNs）. Data Sources： PubMed, Embase, and the Cochrane Library database were searched for articles that （a） targeted human beings and （b） had a study population with BTNs that were confirmed by fine-needle aspiration cytology and/or core needle biopsy. Study Selection： Thirty-two studies relating to 3409 patients were included in this systematic review. Results： Based on literatures, no deaths were associated with the procedure, serious complications were rare, and RFA appears to be a sale and well-tolerated treatment modality. However, a broad spectrum of complications offers insights into some undesirable complications, such as track needle seeding and Hornet syndrome. Conclusions： RFA appears to be a safe and well-tolerated treatment modality for BTNs. More research is needed to characterize the complications of RFA for thyroid nodules.

A report on Kaposiform hemangioendothelioma in the cervical spine

To the Editor:Kaposiform hemangioendothelioma (KHE) is a rare, locally invasive, vascular tumor of infants and adolescents. It has an annual incidence of approximately 0.071 per 100,000 childre ,KHE has a roughly equal gender ratio.It generally affects the soft tissues presenting as mass lesions with associated cutaneous abnormities and Kasabach-Merritt phenomenon (KMP). KHE locating in non-cutaneous sites (such as viscera and retroperitoneum) and those with KMP are reported to be associated with poor prognosis due to a more aggressive disease phenotype.