microwave

摘要： Preionization has been widely employed to create initial plasma and help the toroidal plasma current formation.This research focuses on implementing a simple,economical and practical electron cyclotron resonance(ECR)preionization technique on the newly constructed EXL-50 spherical tokamak,and evaluating the effectiveness on improving the plasma current startup.Two types ECR microwave preionization experiments for the plasma initialization without the central solenoid are reported:(1)2.45 GHz microwave preionization and current startup with2.45 GHz ECR source;(2)2.45 GHz microwave preionization and current startup with 28 GHz ECR source.Application of the 2.45 GHz ECR microwave preionization to the experiments has contributed to(1)getting rid of the plasma breakdown delay;(2)the significant improvement of the discharge quality:the discharge is much longer and more stable while the driven plasma current is larger,compared to the discharge without preionization.

摘要： The n-π^(*) electronic transition in polymeric carbon nitride(PCN)can remarkably harvest visible light,which thus potentially promotes the photocatalytic hydrogen H2 generation.However,awaking the n-π^(*) lectronic transition has proven to be a grand challenge.Herein,we reported on the awakening of n-π^(*) electronic transition by microwave thermolysis of urea pellet,which yielded the PCN with absorption edge of 600 nm,near 140 nm red-shift from 460 nm of pristine PCN.The n-π^(*) electronic transition endows PCN with an increased photocata lytic H_(2) generation,with a highest H_(2) rate of 61.7μmol h^(-1) under visible light exposure,which is near 6 times higher than that by using the PCN from the thermolysis of urea pellets in an electric furnace(10.6μmol h^(-1)).Furthermore,the n-π^(*) transition in PCN leads to the longest wavelength of 535 nm that can initiate H2 generation,remarkably longer than the absorption edge of pristine PCN(460 nm).This work manifests the advantages of microwave sintering route to awaken the n-π^(*) electronic transition in PCN for an increased photocata lytic performance.

摘要： Background: Traditional treatment of axillary odour is the surgical removal of skin and subcutaneous tissue along the edge of the axillary hair in a fusiform shape, which requires the restriction of upper limb activity, has large scars and a high recurrence rate. Minimally invasive methods have developed in recent years. The subcutaneous trimming method with small incision reduces the incision compared to traditional incision, but still requires skin incision, which does not achieve true, minimally invasive treatment. Simple negative pressure suction is difficult to destroy the sweat glands and sebaceous glands in the dermis layer. Thus, we hypothesized that combination of three minimally invasive methods might be more effective. Objective: To explore the clinical effect of combined treatment of axillary osmidrosis by three minimally invasive methods of microwave, scraping & suction and scratching. Methods: From October 2015 to October 2020, 80 patients with underarm odor were enrolled and lacal swelling anesthetic was applied. Microwave was used to treat sweat glands and sebaceous glands in the dermis following the pores. The curettage-aspiration was used to scrape and suck the apocrine sweat glands in the subcutaneous fat layer and the junction between the subcutaneous fat and dermis. To achieve the purpose of minimally invasive and thorough treatment of underarm odor, the spoon scraped the remaining sweat gland tissue. Results: Among 80 patients on 160 sides, all cases (100.00%) were cured on 160 sides at 1 month post-operative follow-up, 75 cases (93.75%) were cured on 150 sides, 5 cases (6.25%) on 5 sides were ineffective at 6-month post-operative follow-up, 74 cases (92.50%) were cured on 148 sides, 6 cases (7.50%) on 5 sides were ineffective at 1-year post-operative follow-up. Complications occurred in 5 cases (6.25%) after operation: 2 cases (2.50%) with skin necrosis on 3 sides, 1 case (1.25%) with uneven skin on 2 sides, 1 case (1.25%) with axillary abscess on 2 sides, and 1 case (1.25%) with keloids on 2 sides. Conclusion: The combination of three minimally invasive methods of microwave, scraping & suction and scratching to treat underarm odor is simple operation, has high cure rate, quick postoperative recovery, and few complications. It is an effective method for minimally invasive and thorough treatment of underarm odor in clinic.

摘要： We are interested in this work to electromagnetic leakage, for example the door of the microwave oven (or shielding of electronic functions working in the microwave band containing holes for ventilation circuit) which must be transparent (chain link) but the level of electromagnetic leakage issued by this device must not exceed certain standards. This work started with this article in which we are interested in a simple structure consisting of a multilayer structure incorporating a radiating aperture. We show in this paper mainly the interests of this study and the limitations of using these structures. Modeling of this device is provided by the wave concept iterative procedure (WCIP) which is simple to implement and is characterized by the fast execution method. The validation of our work is carried out by comparing our results with those calculated by the Ansoft HFSS software which shows a good agreement.

摘要： Journal of Electronic Science and Technology(JEST) is published quarterly. All original contributions are welcomed which relate advances or state-of-the-art achievements in electronic science and technology, including communications systems and networks, signal processing, information and image processing, circuits and systems, microelectronics,electronic devices and materials, computer science, microwave technology, physical electronics, optoelectronics,mechatronics, control and automation, electronics with life science, and new applications of electronics.

摘要： Phenolic compounds present in medicinal and edible plants such as flavonoids, chalcones, coumarins, quinones, and phenolic acids. The antioxidant potential of phenolic compounds shows potent activities for cancer prevention and its treatment. From a green chemistry point of view, cascade (tandem) reactions are ideal techniques in organic synthesis for building complex structures. Cascade techniques are sometimes observed in coupling reactions under mild conditions with a tolerance of multifunctional groups. It will be interesting to find a cascade type reaction to synthesize polyphenolic ethers. This research project achieves a new cross-coupling method for establishing polyphenolic ethers from mixed phenols and halides in the presence of palladium catalyst in moderate to good yields.

摘要： The effect of carbon black(CB),carbon nanotube(CNT),and graphene(G)on foaming,electrical conductivity(EC),and electromagnetic interference(EMI)shielding of polystyrene(PS)foam that has been produced via microwave heating operation and supercritical carbon dioxide(CO2)was studied.Foams containing 1 wt%,CNT,and G reached over 90%porosity after 30 s and 3 min radiation time,respectively;however,PS/CB foam did not expand properly even after 3.5 min.In addition,the expansion ratio of PS/CB and PS/G was one-sixth and one-half of PS/CNT,respectively-due to the great CNT’s ability to convert microwave radiation to heat.EC of solid and porous nanocomposites has been increased via raising filler content;however,PS/CNT displayed the highest value at the same volume fractions.This ascending trend could not endure during foaming,so a remarkable optimum-point has been observed for nanocomposite foams.Eventually,EMI-shielding properties of solid and foam nanocomposites were discussed.

摘要： Objective:Thermal ablation poses challenges in the surgical resection(SR)of small hepatocellular carcinoma(HCC),and its therapeutic outcomes for larger lesions remain debated.Methods:This retrospective study evaluated 729 patients with HCC meeting the Milan criteria,who were treated with curative SR or microwave ablation(MWA)between 2008 and 2014.Overall survival(OS),cancer-specific survival(CSS),disease-free survival(DFS),and local tumor progression(LTP)were compared after propensity score matching(PSM).Co-variates associated with OS,CSS,LTP,and DFS were identified.The risk of death and tumor progression were compared.Results:During the median follow-up of 78.6 months,253 patients were included in each group after PSM.For tumors≤3.0 cm and 3.1–4.0 cm,MWA achieved comparable results in terms of OS,CSS,DFS,and LTP.For tumors 4.1–5.0 cm,MWA had lower OS,CSS,and DFS rates(all P<0.05)than SR.Higher LTP rates were observed in the MWA group for tumors 4.1–5.0 cm,although the difference was not significant(P=0.18).Complication rates(P=0.41)were similar,but MWA led to less estimated blood loss(P<0.01)and shorter postoperative hospitalization times(P<0.01).Conclusions:MWA achieved comparable long-term oncologic outcomes with SR for≤4 cm HCC,with lower complication rates and faster recovery.

摘要： Rhodamine 6G-chromone-derived compounds RD1 - RD4 have been synthesized by condensation of rhodamine 6G hydrazide and substituted chromone aldehydes in ethanol using microwave-assisted reaction. The structures of these synthesized rhodamine 6G derivatives were confirmed by proton nuclear magnetic resonance (1H-NMR), carbon nuclear magnetic resonance (13C-NMR), and high-resolution mass spectra data (HRMS). Colorimetric and photophysical studies show the synthesized compounds selectively detect copper (II) ion in aqueous acetonitrile solution.

摘要： The exploration and development of oil and gas resources have shifted from shallow to deep and ultradeep.The difficulty of rock breaking has also increased,introducing new challenges to traditional rock-breaking technology.Hence,there is an urgent need to develop new rock-breaking technologies to improve the development efficiency of deep oil and gas resources.Therefore,this study focused on the new microwave rock-breaking technology and conducted experimental and numerical simulation research on typical deep,hard rock granite.The research results showed that granite in the microwave field exhibited high-temperature melting and fracture,and the highest temperature could reach 550°C.Under the irradiation of circulating microwaves,a minimum irradiation time threshold of 3 min was needed to cause irreversible damage to the rock.The numerical simulation results showed that the interaction of thermal stress and in situ stress would cause the inside of the rock stratum to separate into a disturbed deterioration area,disturbed unloading area and initial stress area.These results are expected to provide the necessary technical guidance and theoretical support for the research and development of high-efficiency rock-breaking drilling for deep hard rock.