Experimental investigation on segregation and remelting behaviors of boron-containing steel with low carbon

Boron in low carbon steel can improve hardenability and hot ductility remarkably. However, defects including cracks, internal half way cracks, and even breakouts commonly appear during the continuous casting process, due to the segregation and remelting behaviors of boron-containing steel. In the present investigation, morphology characteristics around the crack were observed by optical microscope (OM). The segregation and distribution of boron around grain boundary were observed by secondary ion mass spectroscopy (SIMS), and the remelting phenomenon around the crack was observed by the high temperature confocal laser scanning microscope (CLSM). Results show that BN particles are detected in the crack region, Boron is concentrated at grain boundaries. Due to the boron segregation, liquid phase is observed at 1420–1400 °C and 1340–1330 °C in cooling process with boron content even of 0.0013 wt%. The low and high temperature brittle zones are revealed based on boron segregation and remelting behavior. Keywords: Boron-containing steel, Boron segregation, Remelting behavior, Low carbon steel, Crack generatio

Environmental Drivers of Landscape Fragmentation Influence Intraspecific Leaf Traits in Forest Ecosystem

Habitat fragmentation threatens the sustainability of ecological restoration. Understanding the variation in intraspecific traits helped to reveal the functional resource-use strategies of plants in response to environmental changes. We sampled different landscape types of forest configurations, where the most widespread species was Robinia pseudoacacia. From each plot, from two to five R. pseudoacacia individuals were selected for further examinations. Plant development and leaf traits—leaf area (LA), specific leaf area (SLA), leaf dry matter content (LDMC), and leaf thickness (Lth)—were measured in 135 individuals in total. The effects of plant development and landscape fragmentation on R. pseudoacacia leaf traits were assessed using linear mixed-effects models. The environmental factors explained the changes in leaf traits of R. pseudoacacia individuals, and the effect of stand type was the most significant. Compared with continuous forests, R. pseudoacacia individuals in fragmented forests adopted a more conservative resource-use strategy, with smaller LA and SLA and larger Lth and LDMC values. With an increase in landscape heterogeneity, SLA increased and LDMC decreased. In conclusion, the occurrence of landscape fragmentation plays a substantial role in inducing changes in leaf characteristics. The restoration of fragmented forests to continuous forests requires the appropriate addition of land-use types and systematic adjustment of landscape configurations

Oriented intergrowth of the catalyst layer in membrane electrode assembly for alkaline water electrolysis

While membrane electrode assembly water electrolyzers are a promising renewable energy technology, further optimizations are needed before wide-spread implementation can occur. Here, authors examine a device with a porous membrane that enables oriented catalyst intergrowth to improve performances

The effects of plant secondary metabolites from coniferous needle leaf litter on the leaf litter decomposition of Betula albo-sinensis burk

In this study, leaf litters of Betula albo-sinensis and 5 coniferous species were used as samples. The B. albo-sinensis leaf litter was buried in soil and termly treated with the water extracts of five types of coniferous leaf litter for a 6-month simulation decomposition experiment. The dynamics of mass loss and nutrients (C, N, P, and K) content of leaf litter and the soil enzymatic activities were measured to investigate the effects of plant secondary metabolites (PSM) from coniferous leaf litters on the decomposition processes of B. albo-sinensis leaf litter. The results indicated that the extracts of Pinus tabuliformis, Platycladus orientalis, P. armandii and Larix principis-rupprechtii leaf litters significantly inhibited the whole decomposition process and overall nutrients release of B. albo-sinensis leaf litter, while the extracts of Picea asperata leaf litter exhibited no significant influence. The general suppression of PSM on the soil sucrase, carboxymethyl cellulase and β-glucosidase activities might be the main reason leading to the inhibitory effects of the extracts of P. tabuliformis, P. orientalis, P. armandii and L. principis-rupprechtii leaf litter. The species causing inhibitory effects, especially L. principis-rupprechtii, was not recommended to be planted mixed with B. albo-sinensis, or their planting density should be lower in the mixed forests

Numerical simulation of ultrasonic impact treatment (UIT) assisted laser directed energy deposition (DED) CrCoNi medium entropy alloy process

In order to enhance the microstructure and mechanical properties of additively manufactured metal parts, the application of ultrasonic impact treatment (UIT) after the additive manufacturing process is introduced as a means to modulate and optimize the material's microstructure and properties. This study systematically investigates the effect of UIT on the distribution of residual stresses in CrCoNi medium entropy alloy (CrCoNi-MEA) through numerical simulation. A suitable finite element model and boundary conditions are established to simulate the UIT assisted laser DED process. The reliability of the finite element model is verified by XRD residual test results and EBSD observation results. The numerical simulation results shows that the specimen's surface exhibited predominantly compressive stress within a specific depth range, with the maximum compressive stress in the vertical direction. Furthermore, it is observed that UIT amplitude, frequency, and impact needle diameter also significantly influenced the residual stresses. By appropriately adjusting the UIT parameters, the magnitude and distribution of residual stresses could be further controlled and regulated. In addition, it is found that multiple UITs at different surface locations exhibited no significant mutual influence between each other

Do Silvi-Medicinal Plantations Affect Tree Litter Decomposition and Nutrient Mineralization?

In a silvi-medicinal system, the plant secondary metabolites (PSMs) released from medicinal herbs could affect tree litter decomposition and nutrient release. However, the specific effects of PSMs on arboreous litter decomposition are still not well understood. In this study, the extracts of nine types of medicinal herbs were used to treat Pinus armandii Franch. and Larix gmelinii (Rupr.) Kuzen. litter during a simulated half-year decomposition. The effects of the extracts on the decomposition and the N and P release of the conifer litter were investigated. The results indicated that most of the medicinal herb extracts significantly inhibited the late decomposition of P. armandii litter, whereas only two of them accelerated the entire decomposition process. Only a few significantly affected the decomposition of the L. gmelinii litter. Four of the nine types of extract significantly inhibited the N and P release of the P. armandii litter, while 3/9 and 6/9 inhibited the N and P release of the L. gmelinii litter, respectively. The accelerating effects of the extracts on the cellulase activity and the inhibitory effects on the polyphenol oxidase activity might be responsible for the early acceleration and late inhibition of litter decomposition, while the effects of the extracts on the activities of protease and phosphatase might not be the main reason for the inhibitory or accelerating effects on the N and P release. In general, the inhibitory effects of medicinal herbs on the nutrient cycling of ecosystems should be taken into consideration when building silvi-medicinal systems, especially in P. armandii forests

Clinical application of 3D-Slicer + 3D printing guide combined with transcranial neuroendoscopic in minimally invasive neurosurgery

Abstract To explore the clinical advantages of 3D-Slicer + 3D printing guide combined with transcranial neuroendoscopic in minimally invasive neurosurgery. By collecting the datum of patients who underwent craniotomy under 3D-Slicer + 3D printing guide plate positioning combined with transcranial neuroendoscopic in our hospital from October 2021 to February 2022, this paper introduces the accurate planning and positioning lesions of patients before operation and the minimally invasive operation of intraoperative neuroendoscopic and analyses clinical data such as lesion size and surgical bone window size. We collected the case datum of 16 patients who underwent craniocerebral surgery with 3D-Slicer + 3D printing guide combined with transcranial neuroendoscopic, including 5 males and 11 females, aged 46–76 years, including 6 brain tumors (3 meningiomas, 1 glioblastoma, 2 lung cancer brain metastases), 2 cavernous hemangioma, 7 hydrocephalus and 1 chronic subdural hematoma. The lesions of the 16 patients were located accurately before operation and the target areas were reached quickly during operation. Postoperative imaging datum confirmed that the lesions was removed fully, and the ventricular end of shunt tube was in good position. The technology of 3D-Slicer + 3D printing guide plate combined with transcranial neuroendoscopic is not difficult, which has many advantages such as inexpensive equipment, simple operation, easy learning, accurate positioning, and minimally invasive surgery. It is considered to be a practical technology that is feasible, reliable, convenient for diagnosis, preoperative planning and minimally invasive surgery. It is suitable for promotion in neurosurgery and other surgical departments of all medical institutions

Treatment of brainstem and fourth ventricle lesions by the full neuroendoscopic telovelar approach

Abstract Objective To explore the surgical techniques, advantages, and disadvantages of neuroendoscopic telovelar approach in the treatment of brainstem and fourth ventricle lesions. Methods The clinical data of 5 patients treated by neuroendoscopic telovelar approach from March 2020 to March 2022 were analyzed retrospectively. Results Among the 5 patients, there were 3 cavernous hemangiomas in pontine arm and 2 tumors in brainstem and fourth ventricle. All patients could successfully complete the operation, and 4 patients recovered well, other 1 patient discharged automatically for serious complications of other systems after the operation. Conclusion The telovelar approach has gained popularity as a safe and effective strategy for lesions in fourth ventricular and brainstem. However, without removing the posterior arch of the atlas, it is difficult to enter the upper part of the fourth ventricle under a microscope. Transcranial neuroendoscopy can effectively compensate for the shortcomings of microscopy, whether used as an auxiliary measure for microsurgery or alone with proficient endoscopic techniques, it will provide greater application in minimally invasive surgery for fourth ventricle and brainstem lesions. By utilizing the excellent degree of freedom of transcranial neuroendoscopy, there is no need to open the posterior arch of the atlas, making the surgery more minimally invasive. However, the sample size of this study is small, and it was completed under the very mature neuroendoscopic technology of our team. Its general safety and practicality still require extensive clinical research validation

Additional file 1: of Autophagy promotes metastasis and glycolysis by upregulating MCT1 expression and Wnt/β-catenin signaling pathway activation in hepatocellular carcinoma cells

Primers used for Quantitative real-time PCR. (DOCX 67 kb