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Preparing high‐quality 2D semiconductors represented by transition metal dichalcogenides (TMDCs) is of great importance for the next‐generation devices. However, currently available 2D TMDCs contain many atomic defects, which greatly affect their electronic and optical properties. This review starts with the formation of atomic defects and their effects on the properties of 2D TMDCs. Then, techniques for characterizing atomic defects are systematically summarized, including atomic‐resolution imaging and spectroscopy measurements. Further, recent progress on defect suppression during growth and defect repair after growth is reviewed. Finally, challenges and opportunities in this important field are discussed. [ABSTRACT FROM AUTHOR]

Repairing defects in titanium alloy components is economically justified due to their high cost. In this work, Ti–6Al–4V samples with large area hole defects are repaired by transient liquid-phase sintering. The microstructure and tensile properties after repair have been investigated. The factors of different base powder morphology and the ratio of braze metal are also studied. The results show that by using spherical Ti64 alloy powder with 40 wt% TiZrCuNi braze alloy powder, an overall repair effect with high-density repair zone and good interface combination can be obtained at 960 °C for 3 h. The tensile strength of the as-repaired exceeds that of the matrix, but the elongation is lower than that of the matrix. Finally, the repair experiment conducted at various angles demonstrates this technique's strong practical feasibility.

Many cases of light absorption modification exceeding 700 nm or near‐infrared (NIR) light are reported for capturing more than half of the solar energy, however, very few modifications can produce NIR photoactivity due to the inevitably introduced defects‐induced non‐radiative recombination. Here, taking four kinds of C/O co‐doped red polymeric carbon nitride as examples, defect‐repairing is carried out using alkali metal molten‐salts (LiCl/NaCl and LiCl/KCl) or solid‐salt (KCl) to activate their NIR photoactivity. The defect repair results from the passivation of alkali metal valence electron pairing and the formation of crystalline polyheptazine imide structure with more complete polymerization. More importantly, it sharply eliminates bulk defects (such as carbon vacancy and nitrogen vacancy) introduced by C/O co‐doping. Since structural defects are inevitably introduced in most photocatalysts during expanding light absorption, this proposed strategy is bound to be universal in suppressing defects‐induced non‐radiative recombination to activate NIR photoactivity. [ABSTRACT FROM AUTHOR]

The R programming language that provides a variety of statistical calculation functions is considered to be one of the programming languages most suitable for artificial intelligence.The correctness of the language implementation is a prerequisite for the correctness of the programs developed with such a language.However,there are inevitably many defects in the R programming language.This paper conducts an empirical study on defects in the R programming language and its core packages.By analyzing 7020 issues,we find that:1) Among all the 35 versions involved in these defects,there are the most defects in R 3.1.2,R 3.0.2 and R 3.5.0,and these defects are primarily distributed in a few components such as Documentation,Graphics,Language.2) The components with higher overall defect priority include Startup,Installation and Analyses,and the components with higher overall defect severity include I/O,Installation and Accuracy.There is a significant intermediate correlation between the priority and severity of the defects.3) About 78% of defects could be repaired within one year.4) Semantic faults are the most frequent root cause of defects,in which the “missing feature” and “processing” are more than others.These findings reveal some laws of defects in the R programming language and its core packages.It can assist developers of the R programming language in improving their development quality,assist maintainers of the R programming language in detecting and repairing defects more effectively,and suggest users of the R programming language evade potential risks.

Disputes due to defects in newly built houses are increasing worldwide. A house builder is responsible for repairing any defects in a newly built house. However, since house builders' risk of closure and bankruptcy are increasing due to aggravated disputes and economic crises, builders may become insolvent and fail to perform defect repairs. In preparation for this, many countries have established defect repair deposit or guaranty insurance systems; however, the standards for these systems are not based an objective evidence since the current standards were arbitrarily established during industrialization. It has been pointed out that Korea's housing defect repair deposit has been set excessively high and is being abused in disputes. Based on dispute cases in Korea, this study analyzed housing construction costs, deposits, and defect repair costs, resulting from lawsuits due to defects. The results confirmed that the defect repair deposit has been set too high compared to incurred defect repair costs. In addition, it was found that the guaranty insurance premium in lieu of the housing defect repair deposit was excessive compared to the damage caused by builder insolvency. In order to improve this, in this study, we proposed two alternative plans in which the housing defect repair deposit was set at a certain percentage of the construction cost based on the current Korean standard. In addition, based on the concept of different deposit levels using the scale of housing construction, such as in Australia and Canada, two additional alternative plans with different deposit ratios for each scale of housing construction were presented. The comparison results for housing defect repair deposits and guaranty insurance premiums based on the four presented alternative plans accompanied by actual cases showed that all the alternative plan deposits were higher than the actual defect repair costs. Even in the case of a guaranty insurance premium, the level was at least twice as high as the damage caused by builder insolvency. Therefore, all the alternative plans can fulfill their original role of protecting homeowners in the case of builder insolvency. At the same time, reducing the guaranty insurance premium to reflect the cost of housing construction is possible, and would benefit both house builders and home buyers. The results of this study are valuable as a reference for other countries considering establishing or revising a housing defect repair deposit system. Specifically, these findings, which analyzed the case of Korea's socioeconomic changes as it transitioned from a developing country to a developed country, can provide important information for many developing countries operating housing defect repair deposit policies and systems. [ABSTRACT FROM AUTHOR]

Background: Endoscopic tumor resection and intestinal defect repair are technically challenging leading to invasive surgery and colectomy performed for resection of benign polyps. In this study, we evaluated the use of an endoscopic overtube with bilateral tool channels for these procedures. Methods: Using a fresh porcine colorectum in a 3D ex vivo model, 3 cm lesions at the posterior wall of the transverse colon were removed by two different techniques: standard endoscopic submucosal dissection (ESD) technique (STD, n = 12) and ESD using the overtube with an endoscopic snare and grasper through the bilateral channels (OT, n = 12). Procedure times and the number of muscular injuries were evaluated. Using the same model, 5–10 mm full-thickness perforations within a 3 cm mucosal defect at the posterior wall of the transverse colon were closed by two different techniques: standard endoscopic closure technique (STD, n = 12) and endoscopic closure using the overtube with two graspers (OT, n = 12). The outcomes measured included bursting pressure and the number of endoscopic clips used for closure. Results: Endoscopic resection of lesions was performed by the OT group in a significantly shorter total procedure time (STD vs. OT = median 38.9 min vs. 17.3, p < 0.001) and with fewer muscular injuries (median 0 vs. 2, p = 0.002), compared with the STD group. After repair of intestinal defects, the OT group showed higher median bursting pressures (STD vs. OT = 11.2 mmHg vs. 57.1, p = 0.008) despite using fewer clips (median 13 vs. 10, p < 0.001). Conclusion: This study demonstrates a novel traction technique with an endoscopic overtube using multiple instruments to remove lesions and repair intestinal defects in the colon more effectively. This endoscopic platform could provide a safe alternative to invasive surgical treatment. [ABSTRACT FROM AUTHOR]

Pd membranes can play an important role in H2 separation and purification for the development of sustainable and renewable energies. By supporting on porous substrates, Pd layer thickness can be reduced to several micrometers, thus improving the H2 permeance by several orders of magnitude. However, the supported thin Pd membranes are concomitant with pinhole formation due to either fabrication (e.g., electroless-plating) or thermal treatment, which exist as a remarkable challenge for its widespread applications. This study presents a novel and facile approach for self-repair of Pd membrane defects by immersing the stainless-steel supported Pd membranes in PdCl2 solution. Three membranes were deliberately selected with a low selectivity of 152–1687 (400 ​°C, 0.1Mpa), for which disproportionation reactions between Pd2+ and Fe/Cr/Ni at the defect sites spontaneously occur leading to the formation of Pd particles at the exact point of defects. This self-repair process can be enhanced when applying a high pressure of 30–50 ​bar in the PdCl2 solution for 30 ​min, by overcoming the capillary resistance and penetrating through the pinholes. Interestingly, densely distributed hillocks were observed on the membrane surface probably due to reduction of PdCl2 under following H2 treatment, thus increasing the H2 permeance with a higher effective surface area. The H2/N2 selectivity can be improved by more than one order of magnitude (in the best case from 1687 to 8768) and a long-term stability test of 300 ​h was achieved for the repaired membranes, corroborating the application potential of this approach. [ABSTRACT FROM AUTHOR]

Abstract Objective To describe the clinical outcome and physical condition of patients with locally advanced breast cancer (LABC) who received neoadjuvant chemotherapy followed by mastectomy and latissimus dorsi myocutaneous flap repair. Methods A retrospective review of 142 patients with locally advanced breast cancer was selected from 1156 breast cancer patients in the South and North areas of The Affiliated Calmette Hospital of Kunming Medical University between May 2008 and December 2018. Results All participants (n = 142) were women aged 40–55 years (average age 47.35 ± 0.43 years) who received neoadjuvant chemotherapy followed by mastectomy and latissimus dorsi flap repair. The median follow-up period was 16 months (range 12–24 months). For stage of disease, there were 19 cases (13%) in stage IIB, 31 cases (22%) in stage IIIA, 39 cases (28%) in stage IIIB, and 53 cases (37%) in stage IIIC, which were statistically significant with the physical condition of patients (≤ 0.001). Neoadjuvant chemotherapy was administered to shrink the tumors, and an average tumor size decrease from 10.05 ± 1.59 cm × (8.07 ± 1.54) cm to 6.11 ± 1.72 cm × (3.91 ± 1.52) cm (P < 0.001) was considered statistically significant. A t test was used for the ECOG score statistics, and the results showed that the scores were statistically significant (≤ 0.001) before and after neoadjuvant chemotherapy and after surgery. Conclusions Neoadjuvant chemotherapy is an accepted treatment option for patients with locally advanced breast cancer, and the use of a latissimus dorsi musculocutaneous flap for post-mastectomy reconstruction may improve the patients’ physical condition. Our results indicated that this strategy was safe and feasible.

Chronic tendon ruptures are common disorders in orthopedics. The conventional surgical methods used to treat them often require the support of implants. Due to the non-availability of suitable materials, 3D-printed polycaprolactone (PCL) scaffolds were designed from two different starting materials as suitable candidates for tendon-implant applications. For the characterization, mechanical testing was performed. To increase their biocompatibility, the PCL-scaffolds were plasma-treated and coated with fibronectin and collagen I. Cytocompatibility testing was performed using L929 mouse fibroblasts and human-bone-marrow-derived mesenchymal stem cells. The mechanical testing showed that the design adaptions enhanced the mechanical stability. Cell attachment was increased in the plasma-treated specimens compared to the control specimens, although not significantly, in the viability tests. Coating with fibronectin significantly increased the cellular viability compared to the untreated controls. Collagen I treatment showed an increasing trend. The desired cell alignment and spread between the pores of the construct was most prominent on the collagen-I-coated specimens. In conclusion, 3D-printed scaffolds are possible candidates for the development of tendon implants. Enhanced cytocompatibility was achieved through surface modifications. Although adaptions in mechanical strength still require alterations in order to be applied to human-tendon ruptures, we are optimistic that a suitable implant can be designed. [ABSTRACT FROM AUTHOR]

• Method of Defect Compensation was proposed to reduce the content of ODC, E' center and NBOHC. • The glass has high transmittance with internal transmittance of 99.9%@ 193nm, low stress birefringence with 0.9nm/cm @632.8nm and good optical homogeneity with 0.78ppm @ 632.8nm. Synthetic quartz materials with high ultraviolet transmittance are widely used in lenses and other optical devices. However, the relatively insufficient transmittance limits the application. In this paper, method of Defect Compensation is proposed to reduce the content of ODC, E'center and NBOHC and synthetic quartz glass with UV high transmittance was prepared successfully. The glass has high transmittance with internal transmittance of 99.9%@193nm, low stress birefringence with 0.9nm/cm @632.8nm and good optical homogeneity with 0.78ppm @ 632.8nm. [ABSTRACT FROM AUTHOR]

ObjectiveTo investigate the feasibility and effect of a pedicled submental flap in postoperative defect repair of nasopharyngeal malignant tumors.MethodsEight cases (six women, two men; age, 29–63 years) of postoperative defects after resection of malignant nasopharyngeal tumors with a lesion stage of (r) T1–3N0–2M0 were retrospectively analyzed. Preoperative enhanced thin-slice computed tomography of the neck was performed to predict the submental flap reflux vein. The submental flap was prefabricated during the operation, and the nasopharyngeal mass was removed through the parapharyngeal space approach combined with nasal endoscopy/mandibular external rotation/maxillary overturning. The submental flap was elevated to the nasopharyngeal defect area through the parapharyngeal space for repair.ResultsIntraoperative examination confirmed that among the eight submental flaps, three had venous drainage into the internal jugular vein and five had venous drainage into the external jugular vein; these findings were consistent with the preoperative computed tomography findings. The size of the submental flap was 8–10 cm × 5–6 cm. The repair range reached the eustachian orifice on the healthy side and extended to the posterior wall of the maxillary sinus on the affected side. The flap extended to the posterior upper part of the nasal septum at the top, to the oropharynx at the bottom, and to the bony surface of the skull base at the deep side. Primary healing after surgery was achieved, and no flap necrosis occurred. After 3–77 months of follow-up, one patient with recurrent nasopharyngeal carcinoma after radiotherapy developed cervical lymph node recurrence again, one patient with adenoid cystic carcinoma had lung metastasis, and the remaining six patients had no recurrence.ConclusionsThe pedicled submental flap is used to repair postoperative defects in the nasopharyngeal region through the cervical parapharyngeal space. It is a simple and fast procedure with adequate tissue volumes. The flap can effectively protect important structures such as the internal carotid artery and reduce the risk of infection and bleeding from postoperative wound exposure.

With the aim of understanding the effect of defect types on the mechanical performance of carbon/carbon (C/C) composites, three kinds of defects such as circle arc, square, and triangle shapes were prefabricated on their surfaces. The results show that the prefabricated defects damage the flexural strength of C/C composites compared to the pristine sample (101 ± 6 MPa). The flexural strength of C/C decreased by 30.84%, 45.84%, and 42.58% corresponding to the circle arc, square, and triangle type defects respectively. The defect-repair method with Ni-based solder as the additive was employed to repair the damaged C/C composites. After repair, the stress concentration of C/C composites decreases, and there is a good connection between carbon fiber and the repaired solder so that the load can be transferred continuously, therefore the flexural strength of C/C composites can be improved by 20–28%. [ABSTRACT FROM AUTHOR]

Background and Aim: Cold snare polypectomy (CSP) has received increasing attention in recent years, but few studies have assessed defect repair after polypectomy. Therefore, we compared the repair of mucosal defect after CSP and hot snare polypectomy (HSP) in a rabbit model. Methods: Resection of normal colonic mucosa using both HSP and CSP were performed in 40 male New Zealand white rabbits by an experienced endoscopist. Follow‐up colonoscopy was performed after 7 and 15 days by another endoscopist. We assessed mucosal defect repair, status of healing, scar formation, and intraoperative or delayed complications (including perforation and bleeding). Results: Eight animals died of intraoperative or delayed perforation; follow‐up colonoscopy was performed in 32 animals. On follow‐up colonoscopy at 7 days after operation, 78.1% cases in the CSP group showed healing of mucosal defect compared with none in the HSP group (P < 0.001); mucosal repair score in the CSP group was significantly higher than HSP group (P < 0.001). On follow‐up colonoscopy at 15 days, mucosal defect after CSP had completely healed in all cases (100%) versus 96.9% after HSP (P = 0.313). Among these healed defects, scar formation was observed in 2 of 32 cases in the CSP group compared with 19 of 31 in the HSP group (P < 0.001). Intraoperative perforation rate was significantly higher in the HSP group (15% vs 2.5%; P = 0.048). Conclusions: Mucosal defect repair after CSP is quicker compared with HSP and is more likely to result in scarless healing. HSP is more likely to cause perforation in the thin colon walls. [ABSTRACT FROM AUTHOR]

Objective: To describe the clinical outcome and physical condition of patients with locally advanced breast cancer (LABC) who received neoadjuvant chemotherapy followed by mastectomy and latissimus dorsi myocutaneous flap repair. Methods: A retrospective review of 142 patients with locally advanced breast cancer was selected from 1156 breast cancer patients in the South and North areas of The Affiliated Calmette Hospital of Kunming Medical University between May 2008 and December 2018. Results: All participants (n = 142) were women aged 40–55 years (average age 47.35 ± 0.43 years) who received neoadjuvant chemotherapy followed by mastectomy and latissimus dorsi flap repair. The median follow-up period was 16 months (range 12–24 months). For stage of disease, there were 19 cases (13%) in stage IIB, 31 cases (22%) in stage IIIA, 39 cases (28%) in stage IIIB, and 53 cases (37%) in stage IIIC, which were statistically significant with the physical condition of patients (≤ 0.001). Neoadjuvant chemotherapy was administered to shrink the tumors, and an average tumor size decrease from 10.05 ± 1.59 cm × (8.07 ± 1.54) cm to 6.11 ± 1.72 cm × (3.91 ± 1.52) cm (P < 0.001) was considered statistically significant. A t test was used for the ECOG score statistics, and the results showed that the scores were statistically significant (≤ 0.001) before and after neoadjuvant chemotherapy and after surgery. Conclusions: Neoadjuvant chemotherapy is an accepted treatment option for patients with locally advanced breast cancer, and the use of a latissimus dorsi musculocutaneous flap for post-mastectomy reconstruction may improve the patients' physical condition. Our results indicated that this strategy was safe and feasible. [ABSTRACT FROM AUTHOR]

Deep neural network (DNN) models have been widely used in e-commerce, games, automobiles, manufacturing, and so on. Improper structure, parameters, activation function, or incorrect loss function of the DNN models may cause defects in performance or security. As a result, there are some researches that focus on repairing DNN such as MODE and Apricot. However, the cost of repairing is high or the repair may lead to overfitting. In order to solve this problem, we propose GenMuNN, which is a Mutation-Based Approach to Repair Deep Neural Network Models. First, it analyzes the importance of the weights of the neurons in each layer of the DNN model to the correctness of the final prediction results, and ranks the weights according to the influence on the prediction results of the DNN model. Second, mutation is performed to generate mutants based on the rank of weights, and genetic algorithms are used to select mutants for the next round of mutation until the stop condition is touched. Experiments are carried on a set of DNN models which are trained with the MNIST dataset. The experimental results show that GenMuNN can improve the accuracy of the DNN models. [ABSTRACT FROM AUTHOR]

Controllable repairing the vacancy-defects of BC3 monolayers is significantly important for their fundamental investigations and various applications. We performed first-principles calculations to present a promising strategy of controllable repairing of monovacancies in BC3 monolayer using CO and BF molecules. Two-step repairing process of C monovacancy was performed, the first of which is exposure to CO molecule that provides a C atom to fill the C vacancy, and the second step is removing the extra O atom on the BC3 monolayer via interacting with another CO molecule. In this case, a physisorbed CO2 molecule is formed and leaves the pure BC3 monolayer. However, a three-step repairing procedure for B monovacancy using BF molecule was explored, the first two steps of which are very akin to the case of C monovacancy, but the difference is the chemisorption of the BF2 molecule on the pure BC3 monolayer. We thus explored the third step to remove the BF2 molecule using heating method. At 600 K, BF2 molecule can desorb rapidly from the BC3 monolayer, while whose structural integrity remains. Our study reveals useful insight into the synthesis of perfect BC3 monolayers and presents a proposed strategy for repairing the single vacancies in BC3 monolayers.

Thermal conductivity and thermal dissipation are of great importance for modern electronics due to the increased transistor density and operation frequency of contemporary integrated circuits. Due to its exceptionally high thermal conductivity, graphene has drawn considerable interests worldwide for heat spreading and dissipation. However, maintaining high thermal conductivity in graphene laminates (the basic technological unit) is a significant technological challenge. Aiming at highly thermal conductive graphene films (GFs), this prospective review outlines the most recent progress in the production of GFs originated from graphene oxide due to its great convenience in film processing. Additionally, we also consider such issues as film assembly, defect repair and mechanical compression during the post-treatment. We also discuss the thermal conductivity in in-plane and through-plane direction and mechanical properties of GFs. Further, the current typical applications of GFs are presented in thermal management. Finally, perspectives are given for future work on GFs for thermal management.

A simple and efficient powder metallurgy method to repair the large area hole defect of titanium alloys was addressed in this work. The titanium-based powder mixture was pressed in the defect area by cold isostatic pressing and then sintered at elevated temperature. Three powder systems Ti–Ni/Ti–Sn/Ti–Ni–Sn were chosen according to liquid phase sintering theory. Ti–7Ni–5Sn powder system led to better densification and interface bonding by sintering at 1200 °C. After repair, the strength reached more than 95 % that of the Ti–6Al–4V matrix. • A powder metallurgy method is established to repair defects of Ti alloy parts. • Ti–7Ni–5Sn powder system led to better densification and interface bonding. • After repair, the strength reached more than 95 % that of the Ti–6Al–4V matrix. [ABSTRACT FROM AUTHOR]

Disputes due to defects in newly built houses are increasing worldwide. A house builder is responsible for repairing any defects in a newly built house. However, since house builders’ risk of closure and bankruptcy are increasing due to aggravated disputes and economic crises, builders may become insolvent and fail to perform defect repairs. In preparation for this, many countries have established defect repair deposit or guaranty insurance systems; however, the standards for these systems are not based an objective evidence since the current standards were arbitrarily established during industrialization. It has been pointed out that Korea’s housing defect repair deposit has been set excessively high and is being abused in disputes. Based on dispute cases in Korea, this study analyzed housing construction costs, deposits, and defect repair costs, resulting from lawsuits due to defects. The results confirmed that the defect repair deposit has been set too high compared to incurred defect repair costs. In addition, it was found that the guaranty insurance premium in lieu of the housing defect repair deposit was excessive compared to the damage caused by builder insolvency. In order to improve this, in this study, we proposed two alternative plans in which the housing defect repair deposit was set at a certain percentage of the construction cost based on the current Korean standard. In addition, based on the concept of different deposit levels using the scale of housing construction, such as in Australia and Canada, two additional alternative plans with different deposit ratios for each scale of housing construction were presented. The comparison results for housing defect repair deposits and guaranty insurance premiums based on the four presented alternative plans accompanied by actual cases showed that all the alternative plan deposits were higher than the actual defect repair costs. Even in the case of a guaranty insurance premium, the level was at least twice as high as the damage caused by builder insolvency. Therefore, all the alternative plans can fulfill their original role of protecting homeowners in the case of builder insolvency. At the same time, reducing the guaranty insurance premium to reflect the cost of housing construction is possible, and would benefit both house builders and home buyers. The results of this study are valuable as a reference for other countries considering establishing or revising a housing defect repair deposit system. Specifically, these findings, which analyzed the case of Korea’s socioeconomic changes as it transitioned from a developing country to a developed country, can provide important information for many developing countries operating housing defect repair deposit policies and systems.

Reduced graphene oxide (rGO) is among only a few p-type transparent conductors. This article describes the use of pre-decoration of gold nanoparticles (AuNPs) to tune the optoelectronic properties of rGO film. High-purity Au is sputtered on GO film before the thermal reduction process at 825°C in a H2/CH4 environment. For the optimum 30 s Au sputtering, a high-temperature process transformed the Au nanoballs into nanowires. These conditions resulted in the maximum hole mobility of 158.99 cm2 V−1 s−1 and the minimum sheet resistance of 325.82 Ω□−1. The degree of reduction for the rGO-Au(30s) sample was the highest, since it had the lowest optical transmittance of 0.871 and the lowest bandgap of 3.75 eV. It thus represents the best p-type transparent conductor, with a figure of merit σdc/σop of approximately 8.11. The deconvoluted Raman fit elaborates more on the elimination of defect components on the rGO samples. The integrated area ratio for several defect peaks over a pristine peak was the lowest for the rGO-Au(30s), at 3.98. The AuNPs intervened in the reduction process by repairing the lattice defects for the in-plane carbon sp2, edge, amorphous phase, and out-of-plane sp2–sp3. This was responsible for the great improvement in the carrier transport mechanism and the value of σdc/σop. [ABSTRACT FROM AUTHOR]

In recent years, as for the frequent occurrence of failure accidents of high-grade steel pipelines caused by girth weld cracking, great attention has been drawn to the quality of girth weld and defect repair of high-grade steel pipelines. In terms of the types of girth weld defects of high-grade steel pipelines, the recommended treatment methods for girth weld defects in domestic and foreign repair standards for high-grade steel pipes were introduced, and the research results of the existing welding and non-welding repair technologies were systematically combed. As for welding repair technology, Type B sleeve is the preferred repair technology for repairing high-grade steel pipe girth weld defects. At present, the full-automatic welding technology for horizontal straight welds and circumferential fillet welds for open tee, guard plate and Type B sleeve has basically met the conditions for popularization and application, and is expected to greatly improve the welding efficiency and welding quality. Non-welding repair technology divides into three types: composite material, epoxy sleeve and steel lining composite material repair technology. A series of verification tests were conducted abroad to repair the defects (50% incomplete fusion) of X42 pipeline girth welds with composite materials and steel lining composite materials. Compared with composite materials, steel-lined composite materials perform better in axial tensile load test. In China, steel epoxy sleeve was used to reinforce the girth weld, which was inspected and evaluated to be unnecessary to repair but has defects, and the composite steel lining repair technology was designed based on the composite material and epoxy sleeve repair technology. Finally, the solution and key research directions were put forward to solve the problem of girth weld defect repair of high-grade pipelines, and supposed to provide technical reserves for the safe operation of China–Russia Eastern Gas Pipeline Project and similar high-grade pipelines.

Chronic tendon ruptures are common disorders in orthopedics. The conventional surgical methods used to treat them often require the support of implants. Due to the non-availability of suitable materials, 3D-printed polycaprolactone (PCL) scaffolds were designed from two different starting materials as suitable candidates for tendon-implant applications. For the characterization, mechanical testing was performed. To increase their biocompatibility, the PCL-scaffolds were plasma-treated and coated with fibronectin and collagen I. Cytocompatibility testing was performed using L929 mouse fibroblasts and human-bone-marrow-derived mesenchymal stem cells. The mechanical testing showed that the design adaptions enhanced the mechanical stability. Cell attachment was increased in the plasma-treated specimens compared to the control specimens, although not significantly, in the viability tests. Coating with fibronectin significantly increased the cellular viability compared to the untreated controls. Collagen I treatment showed an increasing trend. The desired cell alignment and spread between the pores of the construct was most prominent on the collagen-I-coated specimens. In conclusion, 3D-printed scaffolds are possible candidates for the development of tendon implants. Enhanced cytocompatibility was achieved through surface modifications. Although adaptions in mechanical strength still require alterations in order to be applied to human-tendon ruptures, we are optimistic that a suitable implant can be designed.

High initial coulombic efficiency is highly desired because it implies effective interface construction and few electrolyte consumption, indicating enhanced batteries' life and power output. In this work, a high‐capacity sodium storage material with FeS2 nanoclusters (≈1–2 nm) embedded in N, S‐doped carbon matrix (FeS2/N,S‐C) was synthesized, the surface of which displays defects‐repaired characteristic and detectable dot‐matrix distributed Fe‐N‐C/Fe‐S‐C bonds. After the initial discharging process, the uniform ultra‐thin NaF‐rich (≈6.0 nm) solid electrolyte interphase was obtained, thereby achieving verifiable ultra‐high initial coulombic efficiency (≈92 %). The defects‐repaired surface provides perfect platform, and the catalysis of dot‐matrix distributed Fe‐N‐C/Fe‐S‐C bonds to the rapid decomposing of NaSO3CF3 and diethylene glycol dimethyl ether successfully accelerate the building of two‐dimensional ultra‐thin solid electrolyte interphase. DFT calculations further confirmed the catalysis mechanism. As a result, the constructed FeS2/N,S‐C provides high reversible capacity (749.6 mAh g−1 at 0.1 A g−1) and outstanding cycle stability (92.7 %, 10 000 cycles, 10.0 A g−1). Especially, at −15 °C, it also obtains a reversible capacity of 211.7 mAh g−1 at 10.0 A g−1. Assembled pouch‐type cell performs potential application. The insight in this work provides a bright way to interface design for performance improvement in batteries. [ABSTRACT FROM AUTHOR]

BACKGROUND: Periosteum, as the storage site and recruitment scaffold of progenitor cells and growth factors, plays an important role in the blood supply of bone tissue and the formation and regeneration of bone. Thus, it has become a research hotspot in recent years to develop an artificial periosteum material which can simulate natural periosteum both in structure and function. OBJECTIVE: To review the research progress of artificial periosteum material and its application in clinical treatment. METHODS: The relevant documents published by PubMed database up to February 2020 were searched by computer with the search term of “periodium, tissue engineering, artificial, regeneration, repair”. RESULTS AND CONCLUSION: The artificial periosteum simulates the structure and function of natural periosteum through three elements: scaffolds, cells and factors, which provide a new possibility for the clinical treatment of periosteal tissue repair and bone regeneration. At present, the artificial periosteum can be divided into cell-sheet periosteum material, acellular-scaffold periosteum material and artificially synthetic scaffold periosteum material. Cell-sheet artificial periosteum is relatively simple to prepare and is a kind of tissue engineering periosteum material which has been put into clinical use earlier. Acellular-scaffold artificial periosteum can keep its natural structure or element to the greatest extent. The material of artificially synthetic scaffold is rich and convenient, and has a low incidence of anti-rejection. These materials all showed good osteogenic effect. However, at present, the bionic research on the structure and function of artificial periosteum is still in its infancy, and further improvement is still needed in material selection, theoretical design and other aspects, so as to make it more mature in biological bionic function. [ABSTRACT FROM AUTHOR]

The rapid repair of graphene oxide (GO) was demonstrated using a microwave cavity resonator that separates pure electric and magnetic fields from microwaves. Reduced graphene oxide (rGO), a high-quality graphene-like material, was obtained using our method. Raman spectroscopy of rGO after microwave treatment revealed that the D band intensity decreased as the temperature increased, while the G and G′ band intensities increased with increasing temperature. Furthermore, the cavity resonator provided better defect repair and oxygen removal from GO than conventional heating, and the microwave magnetic field yielded better quality rGO than the microwave electric field. Microwave heating removed surface impurities and repaired defects in GO more effectively than conventional heating, while suppressing graphitisation. These findings provide guidelines for the microwave-assisted reduction of GO for the fast and large-scale production of graphene. Image 1 • Microwave (MW) heating assessed for fast, large-scale reduction of graphene oxide • MW electric and magnetic fields are separated for pure electric/magnetic heating • MW heating gives better defect repair and oxygen removal than conventional heating • MW magnetic field yields better results than MW electric field [ABSTRACT FROM AUTHOR]

Graphene has excellent theoretical properties and a wide range of applications in metal-based composites. However, because of defects on the graphene surface, the actual performance of the material is far below theoretical expectations. In addition, graphene containing defects could easily react with a matrix alloy, such as Al, to generate brittle and hydrolyzed phases that could further reduce the performance of the resulting composite. Therefore, defect repair is an important area of graphene research. The repair methods reported in the present paper include chemical vapor deposition, doping, liquid-phase repair, external energy graphitization, and alloying. Detailed analyses and comparisons of these methods are carried out, and the characterization methods of graphene are introduced. The mechanism, research value, and future out-look of graphene repair are also discussed at length. Graphene defect repair mainly relies on the spontaneous movement of C atoms or heteroatoms to the pore defects under the condition of applied energy. The repair degree and mechanism of graphene repair are also different according to different preparations. The current research on graphene defect repair is still in its infancy, and it is believed that the problem of defect evolution will be explained in more depth in the future. [ABSTRACT FROM AUTHOR]

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Carbon nanotubes (CNTs) are usually very expensive, but inexpensive CNTs have been mass-produced by a super-growth (SG) method. The SG-CNTs, however, have many defects resulting in a low conductivity, which is a disadvantage of the SG-CNTs. We discovered that even the defective SG-CNTs can provide a good thermoelectric performance by forming ternary hybrid films made of the SG-CNTs, nanoparticles (NPs) of a conducting polymer complex, poly(nickel 1,1,2,2-ethenetetrathiolate) (PETT) and poly(vinyl chloride) (PVC). The good thermoelectric performance of the ternary film (PETT-NP/SG-CNT/PVC) was possibly attributed to the defect repair effect in addition to the bridging effect of the PETT-NPs among the CNTs. In order to confirm this new concept, we attempted the deposition of metal NPs at the defects of the SG-CNTs. We initially made a physical mixture of palladium (Pd) NPs and the SG-CNTs in dispersions to cover the SG-CNT defects with the Pd-NPs. The obtained films showed only a slight improvement in electrical conductivity. Chemical reduction of the Pd ions in the dispersion of the SG-CNTs, on the other hand, provided hybrids with an enhanced electrical conductivity, thus, use as thermoelectric materials. The thermoelectric figure-of-merit was estimated to be ∼0.3, which is a relatively high value for organic hybrid materials. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Liquid Crystal & Displays is the property of Chinese Journal of Liquid Crystal & Displays and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Pt, as a common cocatalyst, has been widely used in photocatalytic H2 evolution. However, the specific role of Pt in photocatalytic H2 evolution has not been thoroughly studied. In this paper, by employing three Pt sources with different charges (positive, negative and neutral), we systematically studied the charge effect of Pt sources on photocatalytic H2 evolution via TiO2 catalyst. According to the results of Raman, X-ray photoelectron spectroscopy (XPS), recycle experiments and photocurrent characterizations, it was found that TiO2 would produce electropositive defects during photocatalytic H2 evolution, inevitably leading to the decline of H2 production activity. Thanks to the electrostatic interaction, the electronegative Pt source not only promoted charge separation, but preferential deposited on electropositive defects, which acted as the defect repair agent, and thus resulted in the increased photocatalytic stability. This work may provide a new perspective for enhancing photocatalytic stability of hydrogen production.

Defects were created on the surface of highly oriented pyrolytic graphite (HOPG) by sputtering with an Ar+ ion beam, then characterized using X‐ray photoelectron spectroscopy (XPS) and time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) at 500°C. In the XPS C1s spectrum of the sputtered HOPG, a sp3 carbon peak appeared at 285.3 eV, representing surface defects. In addition, 2 sets of peaks, the Cx− and CxH− ion series (where x = 1, 2, 3...), were identified in the ToF‐SIMS negative ion spectrum. In the positive ion spectrum, a series of CxH2+• ions indicating defects was observed. Annealing of the sputtered samples under Ar was conducted at different temperatures. The XPS and ToF‐SIMS spectra of the sputtered HOPG after 800°C annealing were observed to be similar to the spectra of the fresh HOPG. The sp3 carbon peak had disappeared from the C1s spectrum, and the normalized intensities of the CxH− and CxH2+• ions had decreased. These results indicate that defects created by sputtering on the surface of HOPG can be repaired by high‐temperature annealing. [ABSTRACT FROM AUTHOR]