Objective The purpose of this study was to explore the situations and factors influencing casual sexual behavior among male college students, in order to provide scientific evidences and measures of the prevention and control for HIV/AIDS. Method Using the stratified cluster sampling method, male college students who self-reported sexual behavior were selected as survey subjects in 13 colleges and universities in 11 cities of Zhejiang Province from October to November 2018. We used a custom online questionnaire to collect information on the demographic characteristics, sexual attitudes, sexual behaviors, and HIV interventions of the respondents. The χ2 test was performed on the composition ratios between different groups. With the occurrence of casual sexual behavior as the dependent variable, logistic regression was used to analyze the factors influencing casual male sexual behavior. Results A total of 2734 male college students were surveyed, aged 20.20±1.41 years, of which 595 had casual sex, accounting for 21.7%. The rate of HIV prevention awareness among the participants was 85.1%. Multivariate analysis showed that receiving a self-assessment of HIV risk conducted by the school (Ajusted OR = 1.45, 95% CI = 1.14–1.84), knowing that HIV self-test kits were available at school (Ajusted OR = 2.02, 95% CI = 1.56–2.62), accepting one-night stands (Ajusted OR = 2.82, 95% CI = 2.18–3.66), accepting commercial sex (Ajusted OR = 1.95, 95% CI = 1.53–2.48), being a man who has sex with men (Ajusted OR = 1.81, 95% CI = 1.37–2.39), being a senior (Ajusted OR = 0.46, 95% CI = 0.30–0.71), having knowledge of HIV/AIDS prevention and treatment (Ajusted OR = 0.66, 95% CI = 0.51–0.86), and knowing that the CDC provides HIV testing services (Ajusted OR = 0.56, 95% CI = 0.41–0.77) were factors influencing male college students’ casual sexual behavior. Conclusion Male college students who have causal sexual behaviors have a high degree of openness in sexual attitudes, insufficient knowledge of AIDS prevention, and knowledge of HIV testing-related information but low testing rates. For male college students’ HIV prevention education intervention, it is necessary to emphasize the establishment of correct sexual attitudes and concepts and promote safe sexual behaviors to prevent the spread of HIV.

The purpose of this study was to understand the homosexual behavior characteristics and influencing factors of male college students and to provide scientific evidence for the prevention of HIV infection in college students.A self-made online questionnaire was used to collect information on demographic characteristics, sexual attitudes, sexual behaviors, and interventions of the respondents. The χ2 test was performed on the constituent ratios of different groups, and whether homosexual behavior occurred was the dependent variable. Logistic regression was subsequently used to analyze the influencing factors of male homosexual behavior.A total of 2665 students were surveyed, including 219 men who have sex with men, accounting for 8.22% of the sample population. Multivariate analysis revealed the following independent influencing factors of homosexual behavior among male college students: the student's household registration was Zhejiang Province, the hometown was in the city, accepted male homosexual sex, had temporary sex in the last year, and awareness that the correct use of condoms can reduce the spread and risk of acquired immunodeficiency syndrome.Various measures should be enacted to promote human immunodeficiency virus/acquired immunodeficiency syndrome education and intervention among college students, especially emphasizing making friends and advocating safe sex to prevent the spread of the disease.

A numerical investigation of the influence of pitch angle on vertical axis wind turbine (V A WT) aerodynamic performance is carried out using the finite volume method. The attack angle of the wind turbine is studied under a speed ratio A = 4, and the pitch angle of the wind turbine is adjusted to optimize the working attack angle and hence the aerodynamic performance of the turbine. The flow is assumed to be 2D fully turbulent and the fluid is incompressible, and turbulence is modeled by the k-w SST. The sliding mesh technique is adopted.The present study shows that an appropriate pitch angle can apparently improve the wind turbine power-coefficient.

Objective. The objective of this study was to understand multiple sexual partners and related factors among male college students who exhibited sexual behaviour to provide a scientific basis for formulating HIV/AIDS prevention measures among college students. Methods. A stratified cluster random sampling method was conducted among 2665 male students who had sexual behaviour and were informed of the number of sexual partners from 13 colleges/universities in 11 cities in Zhejiang Province in 2018. Demographic characteristics, sexual attitudes, sexual behaviour, interventions, and related information were collected using a homemade online questionnaire. The chi-square test or univariate logistic regression in different groups was conducted for multiple sexual partners, and a logistic regression model was used in the related factor analysis. Results. A total of 2665 college students who engaged in sexual behaviour were involved in the research; among them, 485 students (18.20%) had multiple sexual partners. The results of multivariate analysis showed that the participants whose sexual orientation was homosexual ( adjusted   OR = 4.10 , 95 % CI = 2.89 − 5.80 ), those who had received school education about HIV testing in the previous year ( adjusted   OR = 1.55 , 95 % CI = 1.20 − 1.99 ), those who had accepted one-night stands ( adjusted   OR = 3.29 , 95 % CI = 2.43 − 4.47 ), those who had accepted commercial sex ( adjusted   OR = 1.89 , 95 % CI = 1.44 − 2.48 ), and those who were very confident in a condom use measure of self-efficacy ( adjusted   OR = 1.78 , 95 % CI = 1.31 − 2.41 ) were more likely to have multiple sexual partners. The participants who were senior students ( adjusted   OR = 0.51 , 95 % CI = 0.31 − 0.84 ), those whose monthly living expenses were 1001-1500 renminbi ( adjusted   OR = 0.69 , 95 % CI = 0.51 − 0.93 ), those who had known that “daily life and study contact cannot spread HIV” ( adjusted   OR = 0.59 , 95 % CI = 0.43 − 0.80 ), and those who knew that the CDC provides HIV testing ( adjusted   OR = 0.66 , 95 % CI = 0.46 − 0.95 ) were less likely to have multiple sexual partners. Conclusion. Multiple sexual partners were quite common among male college students who engaged in sexual behaviour. They had a separation of HIV/AIDS knowledge and action and a low rate of HIV testing. Further health education and intervention, including informing friends of strategies, are needed to guide students in correct sexual attitudes, safe sexual behaviour, and prevention of the spread of disease.