Tailoring the geometric and electronic structure is dynamically important for designing highly active catalyst materials, which remains a great challenge. Herein, our combined experimental and ...density functional theory (DFT) calculations demonstrate that the electrocatalytic and photoelectrochemical activity of WO
3
changes non-monotonically with the Mn or V doping concentration due to local changes in the reduced nature of WO
3
and the formation of oxygen vacancies. For the hydrogen evolution reaction, at optimal Mn and V doping concentrations, the overpotential to reach ∼10 mA cm
−2
is reduced by −97 mV and −38 mV
vs.
RHE; the Tafel slope is also reduced from 121 to 68 and 41 mV per decade (mV dec
−1
) compared to the undoped WO
3
, respectively. The improved activity arises from the fine tuning of the electronic structure and lessened free energy for atomic hydrogen adsorption. For photoelectrochemical water splitting, the photocurrent density is increased from 0.61 mA cm
−2
for the undoped WO
3
to ∼1.38 mA cm
−2
and 2.49 mA cm
−2
for optimal Mn and V doping, respectively. The photocurrent density at an optimal V doping is approximately 1.8 and 4.1 times higher than that at the optimal Mn doping and undoped WO
3
, respectively. Our work indicates a promising interface-engineering strategy for designing highly active non-precious electrocatalysts and photocatalysts for green energy conversion applications.
•This study performs a full-scale field test using shield machine to cut a diaphragm wall.•The cutterhead design and machine operation parameters are recommended.•The test shows that shield machine ...can effectively break steel reinforced concrete wall.•Cutter wear and wall vibration are relatively small when machine is properly operated.
Shield tunneling during metro construction frequently hits steel reinforced concrete diaphragm walls. A high risk is involved in using a shield machine to cut through a diaphragm wall owing to limited theoretical research and engineering experience. To evaluate the performance of the shield machine and obtain feasible operation parameters, this study conducts a full-scale field test using a shield machine to cut through a diaphragm wall in Suzhou, China. The machine has a diameter of 6.84 m, equipped with 38 disc cutters and 48 scrapers. The wall has a width of 8.8 m, height of 9.7 m, and thickness of 0.6 m, reinforced with 25 mm and 28 mm diameter main steel rebars. The study finds: 1) the shield machine has adequate capacity to cut the diaphragm wall with small wear (maximum amplitude of 0.7 mm) to disc cutters and light damage to scrapers; 2) the concrete is mainly damaged under compression shear and peel-off with 95 % of particle size smaller than 10 cm, whereas the steel rebars are broken under the combined effects of compression shear and pull-apart with five damage modes identified based on different damage mechanism; and 3) a low advance rate (1–2 mm/min) and medium rotational speed (0.6 rpm) are recommended such that the machine can cut the wall smoothly with wall acceleration below 0.15 g and maintains its thrust and toque close to 10 % and 15 % of rated thrust and torque, respectively. The findings prove the feasibility of using a shield machine to cut through a diaphragm wall, and provide guidance for project implementation.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Despite the increasing use of integrated tasks in English as a Foreign language (EFL) academic contexts, few attempts have been made to develop reliable and valid instruments to measure integrated ...writing self-efficacy. To address this research gap, this study developed and validated a scale of self-efficacy for L2 reading-to-write tasks in an EFL academic context. Three dimensions were posited to underlie the construct of L2 reading-to-write self-efficacy (L2RWSE), including self-regulation efficacy, discourse synthesis self-efficacy, and writing conventions self-efficacy. This theoretical underpinning informed the development of the L2RWSE scale. A series of three studies were conducted to interrogate the validity of the scale, involving a total of 1414 participants. Findings from the first two studies, based on exploratory and confirmatory factor analysis respectively, supported our hypothesis that the scale consisted of the three dimensions. Results of multigroup CFA indicated that the scale functioned equivalently on two groups of participants from key and non-key universities. Findings from Study 3 demonstrated that students’ L2RWSE had significant predictive effects on their performance on an integrated reading-to-write task. While shedding light on the construct of L2 integrated writing self-efficacy, the study has important implications for integrated writing assessment and pedagogy.
•L2 reading-to-write self-efficacy (L2RWSE) was conceptualized as a multidimensional construct.•A 19-item L2RWSE scale was developed and validated involving 1404 EFL student writers.•Students’ L2RWSE significantly predicted their performance on a reading-to-write task.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Antiferromagnetic spintronics
is a rapidly growing field in condensed-matter physics and information technology with potential applications for high-density and ultrafast information devices. ...However, the practical application of these devices has been largely limited by small electrical outputs at room temperature. Here we describe a room-temperature exchange-bias effect between a collinear antiferromagnet, MnPt, and a non-collinear antiferromagnet, Mn
Pt, which together are similar to a ferromagnet-antiferromagnet exchange-bias system. We use this exotic effect to build all-antiferromagnetic tunnel junctions with large nonvolatile room-temperature magnetoresistance values that reach a maximum of about 100%. Atomistic spin dynamics simulations reveal that uncompensated localized spins at the interface of MnPt produce the exchange bias. First-principles calculations indicate that the remarkable tunnelling magnetoresistance originates from the spin polarization of Mn
Pt in the momentum space. All-antiferromagnetic tunnel junction devices, with nearly vanishing stray fields and strongly enhanced spin dynamics up to the terahertz level, could be important for next-generation highly integrated and ultrafast memory devices
.
Full text
Available for:
GEOZS, IJS, IMTLJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK, ZAGLJ
The tumor suppressor gene p53 has been implicated in the regulation of epithelial-mesenchymal transition (EMT) and tumor metastasis by regulating microRNA (miRNA) expression. Here, we report that ...mutant p53 exerts oncogenic functions and promotes EMT in endometrial cancer (EC) by directly binding to the promoter of miR-130b (a negative regulator of ZEB1) and inhibiting its transcription. We transduced p53 mutants into p53-null EC cells, profiled the miRNA expression by miRNA microarray and identified miR-130b as a potential target of mutant p53. Ectopic expression of p53 mutants repressed the expression of miR-130b and triggered ZEB1-dependent EMT and cancer cell invasion. Loss of an endogenous p53 mutation increased the expression of miR-130b, which resulted in reduced ZEB1 expression and attenuation of the EMT phenotype. Furthermore, re-expression of miR-130b suppressed mutant p53-induced EMT and ZEB1 expression. Importantly, the expression of miR-130 was significantly reduced in EC tissues, and patients with higher expression levels of miR-130b survived longer. These data provide a novel understanding of the roles of p53 gain-of-function mutations in accelerating tumor progression and metastasis through modulation of the miR-130b-ZEB1 axis.
Full text
Available for:
DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Complete and high-quality deformation monitoring data are critical for shield tunnel construction safety and quality. In engineering practices, data missing frequently occurs during instrumentation, ...adversely impacting further analysis and decision making. Existing imputation methods either ignore the crucial interactions between different parameters during shield tunneling or focus on the global characteristics of deformation data while neglect their local difference. This paper proposes a novel hybrid model, MCCB, combining multi-view matrix completion algorithms, convolutional neural network (CNN), and bidirectional long short-term memory (BiLSTM) algorithms to impute missing deformation values in shield tunnel monitoring data. The performance of the proposed method is verified using bridge deformation data from a practical project in Beijing. Different missing patterns of the bridge deformation data are filled. The experiment results show that the proposed model can effectively learn the various characteristics of the deformation data and outperforms the four selected models and its two sub-models, and can be used to improve the accuracy of the deformation prediction through data imputation. The novelty of this study includes two aspects. First is that the complicated interaction between different parameters and local difference of the data are considered simultaneously. They have not been addressed before by existing studies. Second is that the innovative combination of matrix completion and deep learning algorithm for application in missing deformation values imputation. To our best knowledge, no research on engineering construction has implemented this technique before.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Silk sutures with antibacterial and anti-inflammatory functions were developed for sustained dual-drug delivery to prevent surgical site infections (SSIs). The silk sutures were prepared with ...core–shell structures braided from degummed silk filaments and then coated with a silk fibroin (SF) layer loaded with berberine (BB) and artemisinin (ART). Both the rapid release of drugs to prevent initial biofilm formation and the following sustained release to maintain effective concentrations for more than 42 days were demonstrated. In vitro assays using human fibroblasts (Hs 865.Sk) demonstrated cell proliferation on the materials, and hemolysis was 2.4 ± 0.8%, lower than that required by ISO 10993-4 standard. The sutures inhibited platelet adhesion and promoted collagen deposition and blood vessel formation. In vivo assessments using Sprague–Dawley (SD) rats indicated that the coating reduced the expression of pro-inflammatory cytokines interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α), shortening the inflammatory period and promoting angiogenesis. The results demonstrated that these new sutures exhibited stable structures, favorable biocompatibility, and sustainable antibacterial and anti-inflammatory functions with potential for surgical applications.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
A direct-drive wind-wave combined energy conversion (WWCEC) system that uses a linear-rotary generator (LRG) has aroused much interest recently. Thanks to the application of the LRG, this system has ...the advantages of high energy output, low non-working hours, and low development cost. This paper aims to investigate the suitable topology of LRG for the WWCEC system, and two types of permanent magnet (PM) LRGs (PMLRGs) are proposed and compared. One is a mover-PM machine (MPMLRG) which belongs to the PM synchronous generator, and the other one is a stator-PM machine (SPMLRG) which belongs to the flux-switching PM generator. The performance contrast between both PMLRGs is conducted, including no-load and on-load characteristics, in which the mutual effect and thermal analysis are involved. The assembly complexity and manufacturing cost are also analyzed. The comparison results indicate that the MPMLRG has superiority in output power, and the SPMLRG is easier to assemble. To validate our analysis, an MPMLRG prototype is processed and tested. Furthermore, the levelized cost of energy (LCOE) of the WWCEC system is estimated, underscoring its cost-effectiveness. Some suggestions for suitable LRG topologies for the WWCEC system are summarized in the outlook section.
Considering shortcomings of the current technology in controlling ground surface settlement and reducing the effect of excavation on the surrounding environment. This paper presents an experimental ...study on the flexural performance of composite structures of concrete-filled steel tubes, which are proposed as a new type of pipe-roof structure. It is also called as steel tube slab (STS) structure. The most important feature of this structure is that the adjacent steel tubes are connected using flange plates, bolts, and concrete in the transverse direction, forming the supporting system after pouring concrete. The main design parameters considered in this investigation are the connection type, spacing between the tubes, welding of the top flange, and thickness of the bottom flange. By conducting six flexural experiments, the failure process and crack development in the composite beams and their load–displacement curves are investigated. The results of laboratory tests show that the composite beams exhibit ductile failure. Increasing connections between the steel tubes has an obvious effect on the load-carrying capacity and flexural stiffness. The spacing between tubes can improve the flexural stiffness of STS beams, while having a limited effect on the longitudinal load-carrying capacity of the STS structure. Welding of the top flange and thickness of the bottom flange shows limited effect on the flexural performance of STS composite beams. Moreover, a series of numerical models is established to further identify the optimum tube thickness-to-flange-thickness ratio in terms of the flexural bearing capacity and stiffness. The numerical solutions suggest that the optimum ratio of the flange thickness to the tube thickness is between 1.0 and 1.25. Finally, a theoretical model for the flexural stiffness of the cross-section of this structure is also proposed, and the predicted results are found to be in excellent agreement with the test results. The research results can provide references for design and construction of STS method.
•Crack development and flexural behavior of STS structures are investigated.•The optimum ratio of the flange thickness to the tube thickness is obtained for STS structure.•A theoretical model for the longitudinal flexural stiffness of the cross-section of STS structure is proposed.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Common ankle sprains are often accompanied by injury to the subtalar joint, which eventually leads to subtalar joint instability. Because the clinical manifestations for subtalar joint instability ...are similar to ankle joint injuries, these are often overlooked. This study aimed to establish an animal model of subtalar joint instability to study post-traumatic osteoarthritis of the subtalar joint caused by long-term subtalar joint instability and to provide a reference for future clinical research on chronic subtalar joint instability.
In all, 24 C57BL/6 male mice were randomly divided into three groups: Sham, cervical ligament (CL) transection and CL + calcaneofibular ligament (CFL) transection groups. One week after surgical operation, all mice were trained to run in the mouse rotation fatigue machine every day. During this period, a balance beam test was used to evaluate the motor level and coordination ability of the mice before the operation and three days, one week, four weeks, eight weeks, and twelve weeks after operation. Further, post-traumatic osteoarthritis of the subtalar joint was quantified via micro-CT and histological staining.
The mice in the partial ligament transection group took significantly longer than those in the Sham group to pass through the balance beam and showed an increased number of hindfoot slips. Micro-CT analysis showed that the subtalar bone volume fraction in the CL + CFL transection group and CL transection group was 5.8% and 2.8% higher than that in the Sham group, respectively. Histological staining showed obvious signs of post-traumatic osteoarthritis (PTOA) in the subtalar joint of the ligament transection group.
The transection of CL and CL + CFL can cause instability of the subtalar joint in mice, resulting in a decrease in motor coordination, and long-term instability of the subtalar joint in mice can cause PTOA of the subtalar joint, which is manifested as destruction and loss of articular cartilage.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
PDF
