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1.
Aluminum nitride （AlN） thin films with high c-axis orientation have been prepared on a glass substrate with an Al bottom electrode by radio frequency （RF） reactive magnetron sputtering. Based on the analysis of Berg＇s hysteresis model, the improved sputtering system is realized without a hysteresis effect. A new control method for rapidly depositing highly c-axis oriented AlN thin films is proposed. The N2 concentration could be controlled by observing the changes in cathode voltage, to realize the optimum processing condition where the target could be fixed stably in the transition region, and both stoichiometric film composition and a high deposition rate could be obtained. Under a 500 W RF power of a target with a 6 cm diameter, a substrate temperature of 450 ℃, a target-substrate distance of 60 mm and a N2 concentration of 25%, AlN thin film with preferential （002） orientation was deposited at 2.3 μm/h which is a much higher rate than previously achieved. Through X-ray diffraction （XRD） analysis, the full width at half maximum （FWHM） of AlN （002） was shown to be about 0.28°, which shows the good crystallinity and crystal orientation of AlN thin film. With other parameters held constant, any increase or decrease in N2 concentration results in an increase in the FWHM of AlN.  相似文献   

2.
N2 and N3 are known as the transition points of the three principal stages of fatigue： initial accommodation, accretion of damage and terminal fatigue. Many experiments show that the ratios of N2/Nf and N3/Nf tend to be stable even though the specific N2 and N3 values may fluctuate widely. The primary goal of this research is to study the piezomagnetic field surrounding AISI 1018 steel specimen under repeated loads and to find the ratio values of N2/Nf and N3/Nf by analyzing 11 sets of low-cycle fatigue data. An MTS-810 testing system with a peak capacity of 222 kN was used to obtain the data which consisted of stress, strain, and piezomagnetic field. A computer program was constructed to track the evolution of the piezomagnetic field and regression analysis was carried out to determine N2 and N3 values. It was observed that there exists a consistent relationship between N2 and Nf. The apparent invariance of the ratio N2/Nf implies that N2 may be identified as an index of performance in the early loading response of a specimen that forecasts its fatigue life, Nf. It has been demonstrated that measurements of the magnetic and mechanical hysteresis can yield significant insights into the various stages of the development of a fatigue critical microstructure which culminates in complete rupture of the material.  相似文献   

3.
A novel nano-TiO2-xNx composite was used as photocatalyst and added to the interior wall paint. The average diameter of nano-TiO2-xNx was about 20 nm. The majority crystal component of the sample was anatase and its optical absorption edge was shifted from 387 nm to 520 nm significantly. Nano-composite paint containing different dosage of nano- TiO2-xNx was investigated to study the properties of formaldehyde decomposition in the air. Testing results show that the formaldehyde decomposition ratio of that nano-paint can almost reach above 80%, especially for that of the paint containing 3% （w/w） nano-TiO2-xNx which exceeded 90%. The primary investigation on the reaction kinetics of photocatalytic formaldehyde decomposition indicated that the experiment data well fit the model of first-order reaction kinetics.  相似文献   

4.
This study explored characteristics of young adults’ solidarity during the Covid-19 pandemic by identifying three different profiles, characterized by low (23%), average (54%), and high solidarity (23%). Based on longitudinal Swiss panel data (NT1 = 797, Mage T1 = 12.15 years, 51% female; 28% migration background representing diverse ethnicities; NT2 = 707, Mage T2 = 15.33 years; NT3 = 596, Mage T3 = 18.31 years), the study combined person- and variable-centered approaches to examine whether sympathy, social trust, and peer exclusion at earlier phases in development predicted membership in pandemic-related solidarity profiles (NT4 = 300, Mage T4 = 20.33 years). All developmental predictors were significantly associated with the likelihood of expressing solidarity during the pandemic as young adults.  相似文献   

5.
This work investigated the microwave dielectric properties of A-site substitution by rare earth La3+in(Pb0.5Ca0.5)(Fe0.5Ta0.5)O3(PCFT) system.A single perovskite phase was obtained only when the doping content was 2%.Suitable La3+ doping improved microwave dielectric performances.Excessive La3+doping caused the formation of secondary phase,which resulted in the decreasing of permittivity εrand quality factor Qfvalues.Especially,when the doping content is 2%-5%,permittivity εrwas above 75 and Qfvalues were 6...  相似文献   

6.
1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　Ｉｎｔｈｅｐａｓｔｄｅｃａｄｅｏｒｓｏ ,ｔｈｅｅｘｉｓｔｅｎｃｅｏｆｇｌｏｂａｌａｔ ｔｒａｃｔｏｒｓａｎｄｔｈｅｅｓｔｉｍａｔｅｓｏｆｔｈｅｉｒＨａｕｓｄｏｒｆｆａｎｄｆｒａｃｔａｌｄｉｍｅｎｓｉｏｎｓｈａｖｅｂｅｅｎｉｎｖｅｓｔｉｇａｔｅｄｆｏｒｎｕｍｅｒｏｕｓｄｉｓｓｉｐａ ｔｉｖｅｎｏｎｌｉｎｅａｒｐａｒｔｉａｌｄｉｆｆｅｒｅｎｔｉａｌｅｑｕａｔｉｏｎｓｗｈｉｃｈａｒｅａｕ ｔｏｎｏｍｏｕｓ[1～ 4 ].Ｔｈｅｎｏｎ ａｕｔｏｎｏｍｏｕｓｉｎｆｉｎｉｔｅ ｄｙｎａｍｉ…  相似文献   

7.
Beliefs about emotion utility can influence context-sensitive emotion goals (i.e., desired emotional responses). Although key for emotion regulation, emotion goals have been overlooked in children and adolescents. In 2018–2019 results of Studies 1 and 2 showed that children (N = 192, Mage = 8.65, 47% girls, 96% White) were less motivated by and found anger less useful in confrontation than adolescents (N = 192, Mage = 12.96, 50% girls, 93% White) and adults (N = 195, Mage = 29.82, 51% women, 96% White). The link between emotion goals and beliefs about emotion utility was weaker in children. In 2021, Study 3 (N = 60, 8-year-olds, 47% girls, 90% White) ruled out expectations as a possible explanation for the previous findings. Context-sensitive utility of emotions may be acquired during development.  相似文献   

8.
Multiple-choice (MC) reading comprehension test items comprise three components: text passage, questions about the text, and MC answers. The construct validity of this format has been repeatedly criticized. In three between-subjects experiments, fourth graders (N 1 = 230, N 2 = 340, N 3 = 194) worked on three versions of MC items from the Progress in International Reading Literacy Study 2001 reading comprehension test with relevant components successively deleted: “original version” (text, questions, MC-answers), “version without text” (questions, MC-answers), “version without text and without questions” (only MC-answers). Answering correctly the MC items became more difficult as the relevant information was eliminated. In the two narrative fictional texts presented, the students' performance of the version without text was not better than chance. Conversely in the informational (fictional) text, the students' performance of the version without text was better than chance. In the third condition, students' performance was never better than chance.  相似文献   

9.
The effect of fly ash (FA) and ground granulated blast furnace slag (GGBFS) on chloride migration through concrete subjected to repeated loading was examined. Portland cement was replaced by three percentages (20%, 30%, and 40%) of mineral admixtures. Five repeated loadings were applied to concrete specimens using a WHY series fully automatic testing machine. The maximum loadings were 40% and 80% of the axial cylinder compressive strength (f′c). Chloride migration through concretes was evaluated using the rapid chloride migration test and the chloride concentration in the anode chamber was measured. The results showed that the replacement percentages of mineral admixtures, the curing time and repeated loading had a significant effect on chloride migration through concrete. The transport number of chloride through concrete cured for 28 d increased with increasing FA replacement and markedly decreased with extension of the curing time. 20% and 30% GGBFS replacement decreased the transport number of chloride through concrete, but 40% GGBFS replacement increased the transport number. Five repeated loadings at 40% or 80% f′c increased the transport number of chloride for all mixes.  相似文献   

10.
Acoustic wave propagation in piezoelectric crystals of classes?43m and 23 is studied. The crystals Tl3VS4 and Tl3TaSe4 (43m) of the Chalcogenide family and the crystal Bi12TiO20 (23) possess strong piezoelectric effect. Because the surface Bleustein-Gulyaev waves cannot exist in piezoelectric cubic crystals, it was concluded that new solutions for shear-horizontal surface acoustic waves (SH-SAWs) are found in the monocrystals using different electrical boundary conditions such as electri- cally “short” and “open” free-surfaces for the unique [101] direction of wave propagation. For the crystal Tl3TaSe4 with coefficient of electromechanical coupling (CEMC) Ke2=e2/(C×g)～1/3, the phase velocity Vph for the new SH-SAWs can be calculated with the following formula: Vph=(Va Vt)/2, where Vt is the speed of bulk SH-wave, Vt=Vt4(1 Ke2)1/2, Va=aKVt4, aK=2[Ke(1 Ke2)1/2-Ke2]1/2, and Vt4=(C44/ρ)1/2. It was found that the CEMC K2 evaluation for Tl3TaSe4 gave the value of K2=2(Vf–Vm)/Vf～0.047 (～4.7%), where Vf～848 m/s and Vm~828 m/s are the new-SAW velocities for the free and metallized surfaces, respectively. This high value of K2(Tl3TaSe4) is significantly greater than K2(Tl3VS4)～3% and about five times that of K2(Bi12TiO20).  相似文献   

11.
The adsorption characteristics of Pb on sediments of the Dianshan Lake in Shanghai was studied. The results show that (1)the relationship between the amount q of apparent equilibrium adsorption and the equilibrium concentration C conforms to the Freundlich isothermal adsorption equation; (2) the adsorption and desorption of Pb on sediments are not reversible, that is, adsorption/desorption of Pb exhibits hysteresis; (3) Pb adsorption behavior is initially fast, followed by a slow reaction, and the slow reaction conforms to a reversible first-order reaction; (4) by deducing the Pb adsorption kinetics, four kinetics parameters n, k1, k2, qmax independent of C could be worked out; (5) the equilibrium parameter (K) and the free energy change (ΔG) could also be determined,and the negative values of free energy change (ΔG) indicate the spontaneous nature of the adsorption.  相似文献   

12.
The properties of a two-dimensional vortex system with random columnar defects were studied by cooling the vortex system to zero temperature. The vortex lattice became more and more disordered with increasing pinning strengthf p. At smallf p, a triangular vortex, lattice away from the pins was observed. The peak of structure factorS(G0) of the vortex lattice decreased with pinning strengthf p, which accorded with the finding that the probability of vortex to be pinned increased withf p. Some of our results agreed with experimental findings. Project supported by the Ministry of Science and Technology of China (NKBRSF-G19990646) and Zhejiang Province Scientific Foundation (199031).  相似文献   

13.
研究目的：在＂干清粪＂系统猪粪堆肥过程中,不同添加剂（玉米秸秆、锯末和蘑菇渣）处理对甲烷、氧化亚氮和氨气排放的影响。创新要点：将不同的添加剂（玉米秸秆、锯末和蘑菇渣）应用到快速堆肥系统中进行堆肥,测定了猪粪堆肥过程中甲烷、氧化亚氮和氨气的排放规律,为国内猪粪堆肥的应用提供理论指导。重要结论：玉米秸秆作为添加剂能增加猪粪堆肥过程中氧化亚氮的排放;蘑菇渣添加剂增加了堆肥过程中甲烷的排放,然而减少了氧化亚氮及氨气的排放;锯末处理能增加堆肥过程中氨气的排放。添加剂能显著影响堆肥过程中氮素的损失。  相似文献   

14.
This study examined repeating and growing pattern knowledge and their associations with procedural and conceptual arithmetic knowledge in a sample of U.S. children (N = 185; Mage = 79.5 months; 55% female; 88% White) and adults (N = 93; Mage = 19.5 years; 62% female; 66% White) from 2019 to 2020. Three key findings emerged: (1) repeating pattern tasks were easier than growing pattern tasks, (2) repeating pattern knowledge robustly predicted procedural calculation skills over and above growing pattern knowledge and covariates, and (3) growing pattern knowledge modestly predicted procedural and conceptual math outcomes over and above repeating pattern knowledge and covariates. We expand existing theoretical models to incorporate these specific links and discuss implications for supporting math knowledge.  相似文献   

15.

Objective

To evaluate the potential adjuvant effect of Agrocybe aegerita lectin (AAL), which was isolated from mushroom, against a virulent H9N2 strain in vivo and in vitro.

Methods

In trial 1, 50 BALB/c male mice (8 weeks old) were divided into five groups (n=10 each group) which received a subcutaneous injection of inactivated H9N2 (control), inactivated H9N2+0.2% (w/w) alum, inactivated H9N2+0.5 mg recombinant AAL/kg body weight (BW), inactivated H9N2+1.0 mg AAL/kg BW, and inactivated H9N2+2.5 mg AAL/kg BW, respectively, four times at 7-d intervals. In trial 2, 30 BALB/c male mice (8 weeks old) were divided into three groups (n=10 each group) which received a subcutaneous injection of inactivated H9N2 (control), inactivated H9N2+2.5 mg recombinant wild-type AAL (AAL-wt)/kg BW, and inactivated H9N2+2.5 mg carbohydrate recognition domain (CRD) mutant AAL (AAL-mutR63H)/kg BW, respectively, four times at 7-d intervals. Seven days after the final immunization, serum samples were collected from each group for analysis. Hemagglutination assay, immunogold electron microscope, lectin blotting, and co-immunoprecipitation were used to study the interaction between AAL and H9N2 in vitro.

Results

IgG, IgG1, and IgG2a antibody levels were significantly increased in the sera of mice co-immunized with inactivated H9N2 and AAL when compared to mice immunized with inactivated H9N2 alone. No significant increase of the IgG antibody level was detected in the sera of the mice co-immunized with inactivated H9N2 and AAL-mutR63H. Moreover, AAL-wt, but not mutant AAL-mutR63H, adhered to the surface of H9N2 virus. The interaction between AAL and the H9N2 virus was further demonstrated to be associated with the CRD of AAL binding to the surface glycosylated proteins, hemagglutinin and neuraminidase.

Conclusions

Our findings indicated that AAL could be a safe and effective adjuvant capable of boosting humoral immunity against H9N2 viruses in mice through its interaction with the viral surface glycosylated proteins, hemagglutinin and neuraminidase.
  相似文献   

16.
The aim of this study was to investigate the clinical heterogeneity of Parkinson’s disease (PD) among a cohort of Chinese patients in early stages. Clinical data on demographics, motor variables, motor phenotypes, disease progression, global cognitive function, depression, apathy, sleep quality, constipation, fatigue, and L-dopa complications were collected from 138 Chinese PD subjects in early stages (Hoehn and Yahr stages 1–3). The PD subject subtypes were classified using k-means cluster analysis according to the clinical data from five- to three-cluster consecutively. Kappa statistical analysis was performed to evaluate the consistency among different subtype solutions. The cluster analysis indicated four main subtypes: the non-tremor dominant subtype (NTD, n=28, 20.3%), rapid disease progression subtype (RDP, n=7, 5.1%), young-onset subtype (YO, n=50, 36.2%), and tremor dominant subtype (TD, n=53, 38.4%). Overall, 78.3% (108/138) of subjects were always classified between the same three groups (52 always in TD, 7 in RDP, and 49 in NTD), and 98.6% (136/138) between five- and four-cluster solutions. However, subjects classified as NTD in the four-cluster analysis were dispersed into different subtypes in the three-cluster analysis, with low concordance between four- and three-cluster solutions (kappa value=−0.139, P=0.001). This study defines clinical heterogeneity of PD patients in early stages using a data-driven approach. The subtypes generated by the four-cluster solution appear to exhibit ideal internal cohesion and external isolation.  相似文献   

17.
The dysregulation of social fear has been widely studied in children's shyness, but we know little about how shy children regulate during unfair treatment. We first characterized developmental patterns of children's shyness (N = 304, ngirls = 153; 74% White, 26% Other) across 2 (Mage = 2.07), 3 (Mage = 3.08), 4 (Mage = 4.08), and 6 (Mage = 6.58) years of age. Data collection occurred from 2007 to 2014. At age 6, the high stable group had higher cardiac vagal withdrawal and lower expressed sadness and approach-related regulatory strategy than the low stable group when being treated unfairly. Although shy children may be more physiologically impacted by being treated unfairly, they may mask their sadness to signal appeasement.  相似文献   

18.
Most Piagetian formal operational reasoning tasks show horizontal decalage; that is, subjects pass certain tasks and fail others that have the same logical structure. The study reported here analyzes the importance of individual difference variables, as postulated by the neo-Piagetian theory of Pascual-Leone, in explaining subject performance in formal reasoning. A sample of 72 freshman students were administered a test of formal reasoning having 20 items of different types of reasoning, and the tests of the individual difference variables. Results obtained from multiple regression analyses show that Pascual-Leone's structural M-capacity (Ms) is the most consistent predictor of success in the different formal reasoning tasks, followed by Witkin's cognitive style, and to a much lesser degree Raven's progressive matrices, and Pascual-Leone's functional M-capacity (Mf). It was found that in the total score on the 20 items of formal reasoning, Ms accounted for 23.3% of the variance (R = 0.483, F = 6.39, p = 0.014) and Witkin's Group Embedded Figures Test, increased the multiple R significantly (F = 7.77, p = 0.007) and accounted for 7.6% of the variance. Mf and the Raven test did not make a significant contribution to the regression equation. Correlation coefficients among most of the items having the same reasoning pattern but different content are generally low but statistically significant (p < 0.01). Intercorrelations among items having the same formal reasoning pattern and content are fairly high (p < 0.001). These results emphasize the importance of individual difference variables: information-processing capacity (Pascual-Leone) and oversensitivity to potentially misleading information (Witkin). It is suggested that in order to understand student performance in formal reasoning tasks, we should expect horizontal decalages as a rule and not the exception, as Piaget had postulated. Educational implications are drawn.  相似文献   

19.
Emotion understanding develops rapidly in early childhood. Firstborn children (N = 231, 55% girls/45% boys, 86% White, 5% Black, 3% Asian, 4% Latinx, Mage = 29.92 months) were recruited into a longitudinal study from 2004 to 2008 in the United States and administered a series of tasks assessing eight components of young children's emotion understanding from ages 1 to 5. Cohort sequential analysis across three cohorts (1-, 2-, and 3-year-olds) demonstrated a progression of children's emotion understanding from basic emotion identification to an understanding of false-belief emotions, even after controlling for children's verbal ability. Emotion understanding scores were related to children's theory of mind and parent reports of empathy, but not emotional reactivity, providing evidence of both convergent and discriminant validity.  相似文献   

20.
The three exploratory studies reported here investigate the role of love styles in the early stages of romantic relationships. Study 1 (N = 108) had subjects rate and rank 14 characteristics of prospective romantic partners. As expected, individual's love style scores were related to the characteristics people report as desirable in a relational partner. Several of these effects, however, were moderated by sex. Study 2 (N = 173) revealed that scores on love styles were associated with ratings of opening lines and intensification strategies. None of these effects were moderated by sex. Study 3 (N = 137) investigated the association between love styles and ratings of secret tests among individuals currently involved in a romantic relationship. The results indicated that love styles were associated with ratings of secret tests. These data add to a growing body of literature suggesting that love styles are associated with individual differences in relational and communicative behavior across the life span of romantic relationships.  相似文献   

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