Black phosphorus (BP) is incorporated in the electrochemical detection of uric acid (UA) to form few layers of BP nanosheets (BPNS)-modified glassy carbon electrodes (BPNS/GCE), investigated by means of ultrasound-assisted liquid-phase exfoliation. We find a significant increase in the peak current magnitude and positive potential shift in the electrochemical response of BPNS/GCE, which may be attributed to the larger specific surface area and good charge transfer ability of BPNS. Further, the electrochemical response of BPNS/GCE is evaluated under different conditions to achieve the optimal conditions. UA detection using differential pulse voltammetry (DPV) shows linear response within the range of 1–1000 μM with a detection limit of 0.33 μM. This work reveals new applications of BP nanomaterials in the electrochemical sensing, thereby promoting further advancement in terms of practical applications of two-dimensional nanomaterials.

In order to solve the problem of improper thrust distribution of each thruster of underwater vehicle, the PSO optimization algorithm is used to solve the problem of thrust distribution. According to the spatial layout of the thruster, the algorithm model of the underwater vehicle propulsion system is established. The thrust input is carried out under the broken line search trajectory, and the simulation verifies the thrust allocation results of the PSO algorithm and the traditional pseudo-inverse method. The simulation results show that compared with the traditional algorithm. First of all, the PSO algorithm can set the physical threshold for each thruster to prevent the thruster from having too much thrust. Secondly, it can ensure that the thruster can turn with a reasonable torque to prevent the robot from drifting due to the large thrust gap. This paper provides a theoretical reference for thrust distribution of underwater salvage robot, and has practical engineering significance.

본 연구는 진로결정자기효능감, 진로동기, 진로성숙도와 각 변인 간의 영향 관계를 알아보는 목적이 있다. 이 연구는 연구 대상자가 중국 동북지역의 랴오닝성 심양시에 소재한 대학생 239명을 연구대상으로 설문조사를 실시하였다. 연구 도구는 진 로결정자기효능감 척도, 진로동기 검사, 진로성숙도 척도를 사 용하였다. 분 연구에서 설정한 연구문제의 분석을 위해 수집된 자료는 데이터 코딩을 거쳐 통계프로그램인 SPSS 21.0을 사용 하여 통계분석을 실행하였다. 연구의 결과는 다음과 같다. 첫 째, 진로결정자기효능감이 진로성숙도에 긍정적인 영향을 미치 는 것으로 나타났다. 둘째, 진로결정자기효능감이 진로동기에 긍정적인 영향을 미치는 것으로 나타났다. 셋째, 진로동기가 진 로성숙도에 긍정적인 영향을 미치는 것으로 나타났다. 이와 같 은 연구결과는 직업교육 과정에서 진로에 대한 인식의 역할이 중요하며, 진로결정자기효능감 및 진로동기를 증진하는 것이 필요함을 느꼈다. 끝으로 본 연구의 후속 및 제한문제에 대하 여 논의하였다.

We report the discovery of four quasars with M1450 ≳ −25.0 mag at z ∼ 5 and supermassive black hole mass measurement for one of the quasars. They were selected as promising high-redshift quasar candidates via deep learning and Bayesian information criterion, which are expected to be effective in discriminating quasars from the late-type stars and high-redshift galaxies. The candidates were observed by the Double Spectrograph on the Palomar 200-inch Hale Telescope. They show clear Lyα breaks at about 7000–8000 ˚A, indicating they are quasars at 4.7 < z < 5.6. For HSC J233107-001014, we measure the mass of its supermassive black hole (SMBH) using its Civ λ1549 emission line. The SMBH mass and Eddington ratio of the quasar are found to be ∼108 M⊙ and ∼0.6, respectively. This suggests that this quasar possibly harbors a fast growing SMBH near the Eddington limit despite its faintness (LBol < 1046 erg s−1). Our 100% quasar identification rate supports high efficiency of our deep learning and Bayesian information criterion selection method, which can be applied to future surveys to increase high-redshift quasar sample.

지리적 위치를 차지한 싱가포르는 외교 정책을 바꾸어 대국 간 의 균형 을 유지 해 왔 고 무역 친중 정치 친미의 '대독 전략'을 채택해왔다. 2016년은 싱가포르 대중 국 정책을 조정 한해였고 중미 무역 충돌과 전염병 상황의 영향을 받아 싱가포르 대중국 정책도 새로운 도전에 직면 했다. 현재의 국제 환경에 빨리 적응하기 위해 싱가포르는 대중국 정책을 점차적으로 조정하고 대중국의 우호를 계속 증진 시킨다. 본고는 싱가포르가 향후 유행기에 중국 외교정책에 대한 변화 추세를 분석하는데 중심을 두고 있다.

For applications in cement-based materials, studies on carbon-based nanomaterials have been almost exclusively on carbon nanotubes, carbon nanofibers, and graphite oxide. Graphene sheets (GPs), as a kind of carbon-based nanomaterials, show unusual mechanical, electrical, optical, and other properties. In this paper, the main focus is to enhance the effect of GPs by improving dispersion through ultrasonication and use of surfactant. Then, dispersion and stability are quantitatively measured by comparing absorbance spectra through spectrophotometry and qualitatively observed through digital imaging and SEM imaging. Therefore, the dispersing protocol is optimized and the most effective and stable dispersion is achieved. At last, the piezoresistivities under compressive load of GPs/cement composites pastes at different additions of GPs are studied by comparing with plain cement paste.

Nostalgia refers to the sentimental longing for the valued past (Sedikides, Wildschut, & Baden, 2004). It is considered a bittersweet emotion, involving both wistful joy and sadness (Sedikides et al., 2004). Nostalgia is also a social emotion. Nostalgic memories typically center on social activities involving the self and close others (Wildschut et al., 2010). Prior research has mainly focused on the social and emotional nature of nostalgic narratives, and researchers have only recently started to investigate the motivations triggered by the process of recalling nostalgic narratives. For example, recalling a nostalgic event can heighten people’s motivation to savor such an experience and prolong it (Huang, Huang, & Wyer, 2016). In the current research, we posit that thinking about nostalgic events can trigger another motivation, namely, a desire to revive the past. Whenever people experience nostalgic feelings, they are likely to perceive differences between the present and their memorable past and desire to go back in time (Hepper et al., 2012; Sedikides et al., 2004). This motivation, once activated, can lead people to take actions to change their current state in the hope of reviving the past (Koole & Jostmann, 2004; Kuhl, 1985). This tendency of taking actions to make changes may generalize to subsequent unrelated situations (Kruglanski et al., 2002), and consequently increase consumer switching behavior (Jiang, Zhan, & Rucker, 2014). These predictions were tested across five studies in various consumption contexts. Our findings contribute to consumer research in two important ways, (a) by demonstrating a novel motivational impact of nostalgia on consumer behavior, and (b) by delineating a systematic influence of an unexplored but pervasive emotional factor— nostalgia—on consumer switching behavior. This research also offers practical implications. Conventional wisdom suggests that nostalgia can make consumers prefer products reminiscent of the “old days”. Our findings show that nostalgia can have broader implications for consumer choices and marketers may use it to manage consumer switching behavior.

Bong Joon-ho’s films have a unique narrative style and profound philosophy, and have repeatedly broken box office records with high commercial value, and are deeply recognized by the world film industry and loved by audiences. This article analyzes and summarizes Bong Joon-ho’s films, discusses the creative style and thematic connotation of Bong Joon-ho films, experiences the aesthetic style of “genre narrative strategy” and “problem awareness” of Bong Joon-ho films, and thinks about the trade-off techniques behind Bong Joon-ho’s high box office and high reputation, as well as the film development model.

Purpose- This paper aims to examines the various factors Influencing Sales of Infant Formula Milk in China under the Covid-19 Pandemic, and base on this analysis, to present some measures for the sellers and consumers. Design/methodology- The 846 number of comments for 84 bands form e-commerce platform was taken as the index reflecting consumers’ purchasing behavior, and the properties of various types of infant formula milk (commodity name, gross weight and milk source) were taken as the independent variables to analyze the influencing factors of purchasing behavior of infant formula milk by multiple regression method. Findings- The important factors influencing the purchase behavior of infant formula milk are that product name, source of milk, domestic or imported products, applicable age, and packing unit. And then Consumers tend to buy 200-500yuan barrels of imported infant formula milk. Originality/value – The originality of this study can be found in its context, that is, under the Covid-19 Pandemic. At present, China has achieved the best epidemic control effects, which creates a great opportunity for Chinese brand infant formula milk to go abroad and realize internationalization in the future.

Purpose - It is important to figure out the relationship between tourism carbon emissions and tourism economics for a healthy tourism development. Research design, data, and methodology - Data of this study are collected from 27 provinces (cities) of China. Tourist consumption stripping coefficient is used to calculate tourism carbon emissions. SBM-Undesirable model is used to measure the efficiency of tourism economics under the constraint of tourism carbon emissions. Results - The results show that: during the year of 2005-2015, there are obvious differences in totals and intensities of tourism carbon emissions among 27 provinces and cities which can be divided into three areas. There is a high possibility of underestimating the actual efficiency of tourism economics by leaving tourism carbon emissions out of account, and a high inefficiency caused by tourism carbon emissions will lead a low efficiency of tourism economics. Conclusions - The development of tourism should give consideration to both economic and environmental benefits, and reduce the inefficiency caused by tourism carbon emissions to improve efficiency of tourism economics by improving the level of technical efficiency and promoting technological progress.

Purpose - Performance appraisal has a significant influence on the development of low-carbon tourism distribution. Research design, data, and methodology - Data of this study are collected from 27 provinces (cities) of China. SBM-Malmquist model is used to measure the TFP and its dynamic changes of low-carbon tourism distribution; TOBIT model is used to discuss the factors of TFP of low-carbon tourism distribution. Results - The results show that, there are obvious differences among regional TFP of low-carbon tourism distribution, the average change tends to grow positively in general, and the western region grows fastest on average due to the improvement of technical efficiency and technical progress, while there are technical efficiency improvement but technical regresses in eastern and central regions. The economic scale, economic strength, structure of energy consumption, location quotient and government regulation have a significant positive effect on the TFP of low-carbon tourism; energy intensity, industrial structure and opening degree have a negative effect; investments in fixed assets, intensity of R&D fund and urbanization rate have no significant influence on the TFP of low-carbon tourism. Conclusions - Improving the productivity of low-carbon tourism and reducing regional differences are effective ways to develop low-carbon tourism and enhance tourism competitiveness.