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Cells are naturally surrounded by an electroactive extracellular matrix in vivo, which is composed of a diverse array of charged molecules such as glycosaminoglycans and proteoglycans, together with piezoelectric collagen fibers capable of generating electrical signals in response to mechanical stimuli. In recent years, electroactive scaffold materials have attracted much attention in tissue engineering and regenerative medicine applications, as a biomimetic strategy to recapitulate the natural physiological electrical microenvironment in vivo, which could enhance the differentiation of stem/progenitor cells into specific lineages, thus facilitating tissue repair and regeneration. The key to improving the functional design of electroactive scaffold biomaterials would be to understand the various intracellular signaling pathways that are activated by electrical stimuli. Therefore, this review critically examines the effects of electrical stimuli and/or scaffolds with electroactive properties on directing stem/progenitor cells towards the osteogenic, neurogenic and other lineages, with particular focus on the molecular signaling pathways involved.

Bone degeneration associated with various diseases is increasing due to rapid aging, sedentary lifestyles, and unhealthy diets. Living bone tissue has bioelectric properties critical to bone remodeling, and bone degeneration under various pathological conditions results in significant changes to these bioelectric properties. There is growing interest in utilizing biomimetic electroactive biomaterials that recapitulate the natural electrophysiological microenvironment of healthy bone tissue to promote bone repair. This review first summarizes the etiology of degenerative bone conditions associated with various diseases such as type II diabetes, osteoporosis, periodontitis, osteoarthritis, rheumatoid arthritis, osteomyelitis, and metastatic osteolysis. Next, the diverse array of natural and synthetic electroactive biomaterials with therapeutic potential are discussed. Putative mechanistic pathways by which electroactive biomaterials can mitigate bone degeneration are critically examined, including the enhancement of osteogenesis and angiogenesis, suppression of inflammation and osteoclastogenesis, as well as their anti-bacterial effects. Finally, the limited research on utilization of electroactive biomaterials in the treatment of bone degeneration associated with the aforementioned diseases are examined. Previous studies have mostly focused on using electroactive biomaterials to treat bone traumatic injuries. It is hoped that this review will encourage more research efforts on the use of electroactive biomaterials for treating degenerative bone conditions.

YAP and TAZ are ubiquitously expressed homologous proteins originally identified as penultimate effectors of the Hippo signaling pathway, which plays a key role in maintaining mammalian tissue/organ size. Presently, it is known that YAP/TAZ also interact with various non-Hippo signaling pathways, and have diverse roles in multiple biological processes, including cell proliferation, tissue regeneration, cell lineage fate determination, tumorigenesis, and mechanosensing. In this review, we first examine the various microenvironmental cues and signaling pathways that regulate YAP/TAZ activation, through the Hippo and non-Hippo signaling pathways. This is followed by a brief summary of the interactions of YAP/TAZ with TEAD1-4 and a diverse array of other non-TEAD transcription factors. Finally, we offer a critical perspective on how increasing knowledge of the regulatory mechanisms of YAP/TAZ signaling might open the door to novel therapeutic applications in the interrelated fields of biomaterials, tissue engineering, regenerative medicine and synthetic biology.

Background In recent years, china has paid more and more attention to the status and role of parenting style in the whole education system, and clearly proposed to “Give full play to the important role of family education in the growth of teenagers” In the national long-term education reform and development plan (2010-2020). The junior middle school stage is more important in the whole development process of middle school students, and junior middle school students are in puberty. At this stage, their rapid physical development and intense emotional fluctuations are the “Storm” of emotional development. After all, the education of emotional regulation ability infiltrated by school education and teaching in students' mental health education is limited, there is also a lack of corresponding guidance on whether students can master effective methods of emotional regulation, or some schools have not attracted attention. As the first caregiver of children, the influence of parents on students directly determines their relationship with others and their own management. In this special stage of junior middle school, students want to try their best to get rid of the control of their parents and let their parents treat themselves as “Adults”. Parents still treat them as “Children” As always. This huge contradiction determines that the parenting methods and methods of parents in their children's study and life will also have an impact on their children, thus affecting their emotional regulation. Because of these, this study aims to explore the relationship between parenting style, interpersonal skills and emotional regulation of junior middle school students with hearing impairment in southern minority areas. Subjects and Methods 123valid questionnaires were collected from several representative special schools. Taking the hearing impaired junior middle school students in special education schools in southern minority areas such as nanning, guilin, liuzhou and qinzhou as the main research object, the investigation was conducted through online electronic questionnaire. This study draws on the research results of scholars at home and abroad, and based on the existing relevant theories. The chinese version of the emotional regulation scale (revised by ji junmei (2009) and the chinese version of the chinese version of the chinese version of the chinese version of the chinese version of the chinese version of the emotional regulation scale (pbi) (revised by ji junmei (2010) and yang jiamei) 0 for descriptive analysis, analysis of variance and linear regression analysis. Results The rearing style of hearing-impaired junior middle school students tended to be negative. There were significant differences between men and women in father overprotection. The father overprotection of boys was significantly higher than that of girls; there are significant gender differences in interpersonal communication ability in conflict resolution ability, and boys are significantly better than girls in conflict resolution ability; there are significant differences in self disclosure ability in grades, showing an upward phenomenon in grades; the non only child is significantly better than the only child in moderate rejection ability. The emotional support ability of junior middle school students with hearing impairment in interpersonal communication is significantly stronger than that of single parent families. Conclusion There is a significant positive correlation between the rearing style and interpersonal communication ability of hearing impaired students in junior middle school, in which the emotional warmth of the mother is positively correlated with the ability of interpersonal relationship establishment and conflict resolution, and the refusal and overprotection of the mother are positively correlated with the ability of self disclosure. In terms of emotional ability, there is no difference between men and women, but there is a grade difference, and the third grade is significantly higher than the second grade; there is a significant negative correlation between the emotion regulation ability of junior middle school students and parental care. The more parents care for their children, the less their children's bad emotions will be; there is a significant positive correlation between junior middle school students' bad emotions and parental control. The more parents control their children, the higher the children's bad emotions will be. Parental care, parental encouragement and parental control can significantly predict children's emotional regulation ability; parental care and encouraging autonomy were significantly positive predictors, and parental control had a negative predictive effect on emotional regulation. Acknowledgements The authors acknowledge the project of Guangxi department of education: Research on the construction of early intervention support system for special children aged 3-6 in Guangxi (No.: 2020KY09008); study on the construction of psychological support system for sibling relationship of special children (No.: 2019KY0420) and general research project of humanities and social sciences of the ministry of education in 2021: Research on the strategy of improving the professional quality of county special education teachers in the western region in the new development stage(No.: 21YJA880046); the project of Guangxi department of education in 2022: Research and practice on the “compound” excellent special education teachers training based on the OBE concept.

During spark plasma sintering (SPS), the gas atomized powders experience a sequence of densification mechanisms of particle arrangement, viscous flow, and high temperature creep concurrent with grain growth. However, after short time ball-milling of the original powders, the dramatic change of powder shape affects the thermodynamics (densification mechanisms) and kinetics (mass transfer) of powder densification based on the evolution of characteristic microstructure and densification data. In addition, we establish a theoretical framework to determine an atomic diffusivity DT, by incorporating the contribution of the applied pressure to the densification kinetics. Furthermore, the DT can be utilized to govern powder densification during SPS. Accordingly, a larger DT associated with the irregular metallic glass powder gives rise to faster powder densification, as compared with the original spherical powder without mechanical milling.

In this study, the correlations between the shrinkage behavior, densification mechanism, and atomic diffusivity of the atomized and milled Ti-based crystalline alloy powders are investigated. The densification mechanism of each stage was identified by determining the evolution of the characteristic microstructures at different sintering temperatures in combination with the shrinkage behavior. Importantly, a theoretical framework is established here and elaborate how it can be used to determine the value of the atomic diffusivity DT and a factor g by integrating the interior (related to material properties) and exterior (related to the sintering parameters) variables. This approach can be utilized to provide insights into the active densification mechanisms during spark plasma sintering (SPS). Furthermore, the densification behavior and microstructure evolution of the two types of heat-treated Ti-based alloy powders fabricated by gas atomization and ball milling are compared to validate the framework for different pressures (15, 30, 45, and 60 MPa) and heating rates (30, 60, 90, and 120 K/min). The results indicate that the comprehensive factor g and the atomic diffusivity DT can be used to describe the densification mechanism and thus the shrinkage behavior during each densification stage. Our results provide quantitative proof that the applied pressure and heating rate promote diffusivity to accelerate powder densification during SPS.

GaN-based light-emitting diodes (LEDs) on Si substrates are promising to replace conventional lamps due to the advantages of energy-saving and low-cost of LEDs grown on large-size Si substrates. However, high-density dislocations and cracks of GaN epitaxial films are usually formed that limit the further development and application of GaN-based LEDs. To circumvent the issues, the step-graded AlGaN buffer layers are carefully designed to grow GaN epitaxial films on Si substrates. The mechanisms of dislocations and stresses for GaN epitaxial films controlled by step-graded AlGaN buffer layers are also investigated by analyzing dislocations evolution and stresses relaxation at the hetero-interfaces. Afterwards, 3.0 μm-thick high-quality GaN epitaxial films grown on Si substrates have been obtained, and high-quality GaN-based LED wafers are obtained accordingly with small full-width at half-maximums (FWHMs) for GaN(0002) and GaN(10–12) X-ray rocking curves of 272 and 297 arcsec, respectively. The corresponding vertical-structure LED chips reveal high-performance with a high light output power of 592 mW and a small working voltage of 2.77 V @ 456 nm, at a current of 350 mA. This work provides an effective approach for the growth of high-quality crack-free GaN epitaxial films on Si substrates for the fabrication of high-performance GaN-based devices.

The overall P-PAD-L teaching system of "1 body, 2 wings, 3 steps and 4D feedback" has been innovated: 1 body means PBL and PAD integration, 2 wings are online and offline classrooms, 3 teaching steps include teacher’ presentation, students assimilation, discussion and dialogue, 4D feedback comes from learning process and results, self-evaluation and peer evaluation. In the past three years,the teaching team has followed the educational action research of "problem-plan- implementation-reflection" steps to refine the teaching system.The effectiveness of teaching innovation system has been successively reflected and confirmed in student development and curriculum construction deepening.

Polarity-controlled GaN epitaxial films with Ga- and N-polarity are intentionally obtained by controlling annealing processes of ScAlMgO4 substrates. It is proved by high-angle annular dark-field scanning transmission electron microscopy, in situ reflection high-energy electron diffraction, and scanning electron microscopy that the GaN epitaxial films grown on ScAlMgO4 substrates annealed in an hydrogen atmosphere reveal Ga-polarity, whereas those grown on ScAlMgO4 substrates annealed in an ambient atmosphere show N-polarity. The thermodynamic mechanism of determining the crystal polarity is systematically investigated by first-principles calculations. It is concluded that N atoms prefer to deposit on the top of Ga atoms adsorbed onto Al(Mg)-face ScAlMgO4 substrates, leading to Ga-polarity, whereas Ga atoms preferentially stay on the central of three N atoms stacked onto the O-face ScAlMgO4 substrates, resulting in N-polarity. This work demonstrates a promising approach for the fabrication of GaN-based de...

High-quality AlN epitaxial films have been grown on Si substrates by optimizing the hydrofluoric acid (HF) solution for cleaning of Si substrates. Effect of the Si substrate surface on the surface morphology and structural property of AlN epitaxial films is investigated in detail. It is revealed that as the concentration of HF solution increases from 0 to 2.0%, the surface morphology and the crystalline quality are initially improved and then get worse, and show an optimized value at 1.5%. The as-grown ∼200 nm-thick AlN epitaxial films on Si substrates grown with HF solution of 1.5% reveal the root-mean-square (RMS) surface roughness of 0.49 nm and the full-width at half-maximum for AlN(0002) X-ray rocking curve of 0.35°, indicating the smooth surface morphology and the high crystalline quality. The corresponding mechanism is proposed to interpret the effect of Si substrate surface on surface morphology and structural property of AlN epitaxial films, and provides an effective approach for the perspective fabrication of AlN-based devices.

High-quality GaN-based light-emitting diode (LED) wafers have been grown on Si substrates by metal–organic chemical vapor deposition by designing epitaxial structures with AlN/Al0.24Ga0.76N buffer layers and a three-dimensional (3D) GaN layer. The AlN/Al0.24Ga0.76N buffer layers are directly grown on Si substrates to provide the large compressive stress to balance the tensile stress introduced during the cooling process, and the 3D GaN layer is grown on the Al0.24Ga0.76N buffer layer to reduce the dislocation density of GaN epitaxial films. The as-grown GaN-based LED wafers exhibit very high crystalline quality with full-width at half-maximums for GaN(0002) and GaN(10−12) of 300 and 345 arcsec, respectively, and an internal quantum efficiency of ∼80.1%. Afterwards, the LED wafers are fabricated into vertical-structure LED chips with a size of 1 × 1 mm2 by the standard process. The as-prepared vertical-structure LED chips exhibited a light output power of 569 mW with a working voltage and a wall-plug efficiency of 2.82 V and 57.6%, respectively, at a current of 350 mA. These high-efficiency vertical-structure LED chips are expected to find a wide range of applications in solid-state lighting fields.

High-performance vertical GaN-based near-ultraviolet (UV) light-emitting diodes (LEDs) on Si substrates with an electroluminescence emission wavelength of 395 nm have been fabricated by designing epitaxial structures to reduce the dislocation density and enhance the electron confinement and hole injection. By designing the epitaxial structures with a continuously Al-composition-graded AlGaN interlayer between an Al0.30Ga0.70N layer and an Al0.15Ga0.85N layer, the dislocation density in epitaxial films has been greatly reduced, and high-quality GaN epitaxial films grown on Si substrates with full-widths at half-maximum for GaN(0002) and GaN(10−12) X-ray rocking curves of 260 and 280 arcsec, respectively, have been obtained. Furthermore, by applying an electron blocking layer with 8 periods of AlInGaN/GaN superlattices, both electron confinement and hole injection have been enhanced accordingly. High-performance vertical GaN-based 395 nm UV LED chips show a high light output power of 535 mW and a low forward voltage of 3.10 V at a current of 350 mA, corresponding to a high wall-plug efficiency of 49.3%, which are the best values for GaN-based 395 nm UV LEDs ever reported. These high-performance near-UV LED chips find application in medical curing, lighting, etc.

High-performance nonpolar a-plane GaN-based metal–semiconductor–metal (MSM) ultraviolet (UV) photo-detectors are fabricated based on high-quality nonpolar a-plane GaN epitaxial films grown on LaAlO3(100) substrates. By effectively controlling the interfacial reactions between GaN and LaAlO3(100) through low temperature growth by pulsed laser deposition, together with systematically studying the formation mechanism of GaN/LaAlO3 hetero-interfaces by first-principles calculations, high-quality nonpolar a-plane GaN epitaxial films with no interfacial layer are obtained. The as-grown ∼300 nm-thick nonpolar a-plane GaN epitaxial films grown at a low temperature of 450 °C show high crystalline quality with the full-width at half-maximum values of 0.21° and 0.41° for GaN(11−20) and GaN(10−11) X-ray rocking curves, respectively; and a very smooth surface with a root-mean-square surface roughness of 1.2 nm. These high-quality nonpolar a-plane GaN epitaxial films are then fabricated into MSM UV photo-detectors, which reveal a high responsivity of 1.35 A W−1 with a low dark current of 8.2 nA @ 5 V. These are the best values for nonpolar GaN-based MSM UV photo-detectors ever reported. These high-performance nonpolar a-plane GaN-based MSM UV photo-detectors have immense potential for application in UV warning and curing systems and light therapy devices.

A high-quality AlN epitaxial film has been grown on a Si(111) substrate by metal–organic chemical vapor deposition through designing the AlN nucleation layer. The structure of a low temperature nucleation layer hinders the formation of amorphous SiNx in the AlN/Si heterointerface, reduces the dislocation density, and thereby improves the crystalline quality of the AlN epitaxial film. The influence of nucleation layer temperature on the surface morphology and the crystalline quality of the AlN epitaxial film is also revealed in detail. The AlN epitaxial film with the optimized nucleation layer grown at a temperature of 800 °C shows a sharp AlN/Si heterointerface, with an XRD full-width at half-maximum for AlN(0002) of 0.30°, and a very smooth surface with a root-mean-square surface roughness of 1.9 nm. Meanwhile, the 200 nm-thick AlN epitaxial film is almost fully relaxed with an in-plane tensile strain of only 0.42%. This work provides an effective approach for the growth of high-quality AlN epitaxial films in the application of AlN-based ultraviolet photonic devices and GaN-based optoelectronic devices.

The anisotropic surface etching behavior of nonpolar a-plane GaN (110) epitaxial films, grown by pulsed laser deposition, was investigated experimentally by wet chemical etching. Crystal-orientation dependent face state, induced by anisotropic growth kinetics, is the origination of the anisotropic properties of the a-plane GaN epitaxial films. Defects that propagate into the surface offer initial positions for the etching process. A joint effect of two factors determines the etching-exposed surface morphology, primarily including triangular prisms and pits, thus making wet chemical etching a promising tool for the investigation of defect distribution. Type I1 basal stacking faults and partial dislocations are proven to have a direct connection with etching-exposed triangular prisms and pits, respectively. This study presents a mechanism research from the standpoint of the evolution process of the surface morphology during the etching process and brings insight for further understanding of the anisotropic properties of the nonpolar GaN epitaxial films for the realization of a high polarization light-emission device, which has a broad application in display and backlighting.

AlN/nitrided sapphire and AlN/non-nitrided sapphire hetero-structures epitaxially grown by pulsed laser deposition (PLD) have been carried out. The characterizations find that when the nitridation process is implemented on sapphire substrates, the properties of AlN/sapphire hetero-structures are improved significantly. It is also identified that very smooth AlN surface with the root-mean-square surface roughness of 1.5 nm, full-width at half-maximums for AlN(0002) and AlN(10–12) X-ray rocking curves of 0.59°and 0.91°. Abrupt AlN/sapphire hetero-interfaces are obtained in AlN/nitrided sapphire hetero-structures. These high-quality AlN/nitrided sapphire hetero-structures shed light for the fabrication of highly-efficient AlN/nitrided sapphire-based devices.

We report a novel microstructure evolution and corresponding mechanical behavior of bimodal eutectic (Ti 63.5 Fe 26.5 Co 10 ) 82 Nb 12.2 Al 5.8 alloys processed by semi-solid sintering (SSS) of the as-milled alloy powders with various glass contents resulted from various milling times. Results show that the as-milled alloy powders have more homogeneous element distribution and higher content of glassy phase with increased milling time. Correspondingly, although the SSSed bulk alloys possess the same constituted phases of the bcc β-Ti, bcc B2 Ti(Fe, Co) and fcc Ti 2 (Co, Fe), their eutectic structures containing bcc β-Ti and bcc B2 Ti(Fe, Co) evolve from irregular eutectic, to partial coarse eutectic, to fine cellular eutectic matrix, and finally to typical nano and ultrafine lamellar eutectic matrix. Interestingly, it is the first time to report that the lamellar eutectic matrix has an bimodal structure consisting of interleaving nano- and ultrafine-grained B2 Ti(Fe, Co) and bcc β-Ti lamellae. Corresponding to the evolution of eutectic structure, the SSSed bulk alloys exhibit a gradual increase in yield strength and plastic strain. Especially, the SSSed bimodal eutectic alloy has ultra-high yield strength of 2050 MPa and large plasticity of 19.7%, superior to those of equivalent counterparts. Theoretically, strengthening mechanism of the SSSed bimodal eutectic alloy can be mainly rationalized as ordering strengthening of B2 superstructured Ti(Fe, Co) and coherency strengthening between bcc β-Ti and bcc B2 Ti(Fe, Co) lamellae inside the lamellar eutectic matrix.

We report on a novel approach to design typical ultrafine lamellar eutectic structure in bimodal alloys fabricated by semi-solid sintering (SSS) of a eutectic mixture. In our work, ultrafine lamellar eutectic structure was implemented by controlling the phase composition of eutectic reaction, and consequently by regulating the structure of eutectic reaction-induced liquid phase through varying component number. Microstructure analysis indicate that although all SSSed alloys have the same three phase constitutions of bcc β-Ti, bcc Ti(Fe, Co), and fcc Ti 2 (Co, Fe), the morphology and distribution of the eutectic structure transforms from limited length and minor quantity, to partial fine alternating bcc β-Ti and bcc Ti(Fe, Co) lamellae, and further to typical complete ultrafine alternating continuous lamellae in the SSSed ternary Ti-Fe-Co, quaternary Ti-Fe-Co-Nb, and quinary Ti-Fe-Co-Nb-Al alloys. Interestingly, the SSSed Ti-Fe-Co-Nb-Al alloy presents a novel bimodal microstructure of coarse fcc Ti 2 (Co, Fe) surrounded by an ultrafine lamellar eutectic matrix containing ultrafine bcc β-Ti and bcc Ti(Fe, Co) lamellae. This bimodal microstructure exhibits ultra-high yield strength of 2050 MPa with plasticity in compression of 19.7%, which exceed published values of equivalent materials. Our results provide a novel pathway for fabricating new-structure metallic alloys for high-performance structural applications.

High-quality AlN epitaxial films have been epitaxially grown on Cu(111) substrates by pulsed laser deposition (PLD) through effectively controlling the interfacial reactions between AlN epitaxial films and Cu substrates. The interfacial properties of the as-grown AlN/Cu hetero-interfaces and their formation mechanisms have been systemically studied. A 2.1 nm-thick CuxAl1−xN interfacial layer is formed in AlN/Cu hetero-structures at a high growth temperature of 600 °C, while abrupt and sharp AlN/Cu hetero-interfaces with no interfacial layer are achieved by effectively controlling the interfacial reactions at a low growth temperature of 450 °C. The as-grown ∼300 nm-thick AlN epitaxial films grown at 450 °C show very smooth surfaces with a root-mean-square surface roughness of 1.2 nm and high crystalline quality with full-width at half-maximum values of X-ray rocking curves for AlN(0002) and AlN(10−12) of 0.7° and 0.8°, respectively. Meanwhile, the residual stress in the as-grown AlN epitaxial films is also well controlled through low temperature growth with a residual compressive stress of 0.30 GPa. These high-quality AlN epitaxial films are of paramount importance for the commercial development of high-performance AlN-based optoelectronic devices.

The polarity of GaN epitaxial films grown on LiGaO2(001) substrates by pulsed laser deposition has been well controlled. It is experimentally proved that the GaN epitaxial films grown on nitrided LiGaO2(001) substrates reveal Ga-polarity, while the GaN epitaxial films grown on non-nitrided LiGaO2(001) substrates show N-polarity. The growth mechanisms for these two cases are systematically studied by first-principles calculations based on density functional theory. Theoretical calculation presents that the adsorption of a Ga atom preferentially occurs at the center of three N atoms stacked on the nitrided LiGaO2(001) substrates, which leads to the formation of Ga-polarity GaN. Whereas the adsorption of a Ga atom preferentially deposits at the top of a N atom stacked on the non-nitrided LiGaO2(001) substrates, which results in the formation of N-polarity GaN. This work of controlling the polarity of GaN epitaxial films is of paramount importance for the fabrication of group-III nitride devices for various applications.

High-quality GaN epitaxial films have been grown on magnesium aluminate scandium oxide (ScMgAlO 4 ) substrates at low temperature of 450 °C with an in-plane epitaxial relationship of GaN[1-100]//ScMgAlO 4 [1-100]. It is found that the ~300 nm-thick GaN epitaxial films grown at 450 °C show the full-width at half-maximums (FWHMs) for GaN(0002) and GaN (10-12) of 0.18° and 0.40°, respectively, and very smooth surface with a root-mean-square (RMS) surface roughness of 1.5 nm. There is no interfacial layer existing between GaN and ScMgAlO 4 . However, as the growth temperature increases, the crystalline quality, surface morphology, and interfacial properties of as-grown GaN epitaxial films are deteriorated gradually. These GaN epitaxial films are of great importance for the fabrication of highly-efficient GaN-based devices.

This study presents the effects of Zr addition on microstructure, phase composition, and superelasticity of Ti-24Nb-xZr (at.%, x = 0, 2, 6) alloys fabricated by spark plasma sintering (SPS). The obtained microstructures were studied using X-ray diffraction and electron microscopy, and the mechanical properties and shape memory properties were evaluated through both compressive testing and cyclic compression experiments. The results show the addition of Zr is beneficial to the formation of the α’’ phase and β-Ti grain refinement. The sintered Ti-24Nb-6Zr shows better compressive yield strength (1457 MPa), ultimate strength (2458 MPa), and strain (45.31%). Cycle compression tests reveals that the Ti-24Nb-6Zr alloy demonstrates stable recoverable strain of 4.11% and remarkable recovery strain rate of 98.1% in the second cycle, and a maximum 7.8% recovery strain and good recovery strain rate of 82.4% in the fifth cycle. In contrast, the sintered Ti-24Nb alloy exhibits recoverable strain of 4.58%, a recovery strain rate of 96.6% in the third cycle, and only 48.8% recovery strain rate in the fifth cycle. The transmission electron microscopy results indicate that the formation of microcracks and dislocations during the cycle compression results in significant recovery strain reduction for the Ti-24Nb alloy. The results provide guidelines to design high-performance Ti-24Nb-based alloys with excellent shape memory properties for structural applications.

2D group-III nitride materials have shown a great promise for applications in optoelectronic devices thanks to their thickness-dependent properties. However, the epitaxial growth of 2D group-III nitrides remains a challenge. In this work, epitaxial growth of 2D GaN with well-controlled lattice structures and bandgaps is achieved by plasma-enhanced metal organic chemical vapor deposition via effective regulation of plasma energy and growth temperature. The structure of graphene/2D GaN/Si heterostructures is carefully investigated by high-resolution transmission electron microscopy. The formation mechanism of the 2D GaN layer is clearly clarified by theoretical calculations. Furthermore, a bandgap for 2D GaN ranging from ≈4.18 to ≈4.65 eV varying with the numbers of layers is theoretically calculated and experimentally confirmed. 2D GaN with well-controlled lattice structure and bandgap holds great potential for the development of deep ultraviolet light-emitting diodes, energy conversion devices, etc.

The polarity of GaN epitaxial films grown on LiGaO

In order to promote the light output powers of GaN-based light emitting diodes (LEDs), two kinds of novel corrosive liquids have been developed in this paper to roughen the surface of the indium tin oxide (ITO) current spreading layer of LEDs. As a result, the textured transparent ITO layer greatly enhanced the external quantum efficiency of the LEDs. Provided that a wafer sample was dipped in a kind of corrosive liquid developed by us for only about 60 s, the light output powers of the LEDs can be promoted by 24.7%, compared with conventional GaN-based LEDs. It is obvious that the presented method is simple, rapid and cost-effective. GaN-based light emitting diodes (LEDs), corrosive liquid, light output power, textured ITO

Due to the superior thickness-dependent properties, 2D materials have exhibited great potential for applications in next-generation optoelectronic devices. Despite the significant progress that has been achieved, the synthesis of 2D AlN remains challenging. This work reports on the epitaxial growth of 2D AlN layers via utilizing physically transferred graphene on Si substrates by metal-organic chemical vapor deposition. The 2D AlN layers sandwiched between graphene and Si substrates are confirmed by annular bright-field scanning transmission electron microscopy and the effect of hydrogenation on the formation of 2D AlN layers is clarified by theoretical calculations with first-principles calculations based on density functional theory. Moreover, the bandgap of as-grown 2D AlN layers is theoretically predicted to be ≈9.63 eV and is experimentally determined to be 9.20-9.60 eV. This ultrawide bandgap semiconductor shows great promise in deep-ultraviolet optoelectronic applications. These results are expected to support innovative and front-end development of optoelectronic devices.

Voltage-controlled oscillator (VCO) with large tuning range and low phase noise is implemented by using 0.18 µm CMOS process. Active inductor and LC filter at tail currents were used to enlarge the tuning range and to improve phase noise of CMOS VCO. Accumulation varactors are used to widen frequency tuning. The tuning range and phase noise were measured as 29% and −120 dBc/Hz at 1 MHz offset, respectively. In addition, the output frequency is between 2.61 GHz and 3.14 GHz for 1.8 V power supplies.