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The purpose of analyzing the subjective and objective factors affecting the timeliness of college English teaching is to develop corresponding strategies to enhance the timeliness of College English teaching. In this paper, an evaluation index system for the timeliness of college English teaching is constructed, and the basic process of fuzzy comprehensive evaluation method using fuzzy numerical analysis is designed. The optimal solution is found by comparing the corresponding objective function values after the bat position is updated, and the weights of the evaluation indexes are selected adaptively to ensure the objectivity of the index weights. In order to be able to more intuitively analyze the relevant factors affecting the timeliness of College English teaching, the questionnaire was used to obtain the evaluation index data, and numerical analysis was conducted for relevant and fuzzy comprehensive evaluation. The results show that the adaptive selection of indicator weights using the BA algorithm reaches the optimal convergence value of 0.504 after 10 iterations, and the weight of the evaluation indicators obtained at this point best reflects the distribution of English teaching effectiveness variables. The comprehensive evaluation score of the fuzzy numerical analysis carried out in College A is 2.1534, and the rating is in the middle, so its teaching content and methods need further improvement. The use of a fuzzy numerical combined evaluation index system can deeply excavate the relevant influencing factors of college English teaching timeliness, help college English teachers to innovate more effective teaching methods, and finally improve the timeliness of college English teaching.

The unstable nonlinear Schrödinger models illustrate the time evolution of disturbances in marginally stable or unstable media. In this article, an improved auxiliary equation method is proposed for conformable fractional-order nonlinear evolution equations to obtain the novel wave solutions of space–time fractional unstable and modified unstable nonlinear Schrödinger equations. Several types of novel wave solutions are constructed in forms of some special Jacobi elliptic functions, rational, exponential, trigonometric and hyperbolic functions in which various are unique and having key utilization in quantum physics. With the aid of appropriate values to parameters, different shapes of bright, dark, kink type soliton, multi-peak solitons, periodic solitary waves etc. are depicted. These distinct physical structures are helpful in the understanding the complex physical interpretation of unstable dynamical models. Furthermore, this article gives an idea, how can reduce the conformable fractional order unstable nonlinear Schrödinger equations into an ODE of one variable to obtain the exact solutions. The numerous obtained waves and other solutions reveal the usefulness of the proposed technique which can be utilized to other nonlinear fractional models arising in quantum physics and other fields of applied sciences.

As the switch for the start-up of the nozzle at the rear of the recoilless gun, the opening pressure of the blocking sheet directly affects the balance of the recoilless gun during the shooting process. The opening time of the blocking sheet is obtained through high-speed camera by capturing the tail flame. Using piezoelectric pressure sensors, the pressure at different positions along the barrel were measured. Furthermore, the pressure at the moment of opening the blocking sheet was determined based on its opening time. A significant force jump (Δ f = 146.9 kN) in the unbalanced recoil experienced by the recoilless gun during the initial firing stage was identified based on the theory of one-dimensional recoilless gun balanced interior ballistics. This jump arises from the opening pressure of the blocking sheet surpassing the projectile's starting pressure (P 0). This research can provide a reference for the design of recoilless weapons related to unbalanced force. [ABSTRACT FROM AUTHOR]

In response to the incident of tourists falling into the sea due to waves on the seawall berm at Macau Road, Qingdao, during the passage of Typhoon "Songda" in 2022, a combination of numerical simulations and physical model experiments was performed to investigate the mechanics of the event, with emphasis on the wave flow characteristics and the flow evolution process on the seawall berm as well as the force exerted on a human body-equivalent cylinder model. The study found that the thickness of the return flow was significantly greater than that of the overtopping flow on the landward part of the berm. The recoil forces applied to the model on the berm were larger than the impact forces, and the ratio tended towards 1 as the wave height increased. In addition, the stability of pedestrians on the seawall berm was analyzed. The instability conditions for pedestrians in cross-wave flows differed slightly from those in floods. [ABSTRACT FROM AUTHOR]

A novel axially chiral all-hydrocarbon cyclo[7] (1,3-(4,6-dimethyl)benzene (CDMB-7) was designed and synthesized using atroposelective[2 + 5] cyclization through Suzuki–Miyaura coupling. CDMB-7 adopts an irregular bowl-like shape with C2 symmetry and exhibits two diastereoisomers in its crystallographic structure. The conformational isomers of CDMB-7 racemates remain stable at high temperatures (393 K). High-performance liquid chromatography (HPLC) confirmed that a single chiral isomer will spontaneously undergo racemization within 30 min at room temperature. This finding opens up possibilities for achieving adaptive chirality in all-hydrocarbon cyclo[7] m-benzene macrocycles. [ABSTRACT FROM AUTHOR]

A noise attenuation performance test was conducted on earmuffs using a recoilless weapon launch platform in a confined space, along with two acoustic test fixtures (ATFs). The overpressure at the ATF's effective tympanic membrane comprised direct sound at 185 dB sound pressure level (SPL) and reflected sound at 179 dB SPL. Wearing earmuffs reduced these peaks to 162 dB SPL and 169 dB SPL, respectively. The reflected sound from walls was defined as delayed sound. An analytical model for earmuff noise attenuation simulated their effectiveness. The simulation revealed that when the earmuffs attenuated delayed sound, the acoustic impedance of acoustic leakage and the acoustic impedance of the earmuff material decreased by 96% and 50%, respectively. The negative overpressure zone between direct and delayed sound decreased the earmuffs' fit against the ATF. Additionally, the enclosed volume between the earmuff and the ear canal decreased by 12%. After the installation of bandages on the earmuffs, the overpressure peak of delayed sound was reduced by 5 dB. Furthermore, the acoustic impedance of the earmuff's sound leakage path and the acoustic impedance of the earmuff material deformation path increased by 100% and 809%, respectively. [ABSTRACT FROM AUTHOR]

BACKGROUND The application of high frequency infrared carbon-sulfur analyzer to determine the organic matter in agricultural soil samples avoids the traditional method of sample liquid conversion. The method has a high measurement efficiency, but has problems such as low electromagnetic induction of soil samples and greater influence of the matrix. OBJECTIVES To solve the problems of low electromagnetic induction and large matrix effect in the determination of organic matter in agricultural soil samples. METHODS The iron and tungsten flux was optimized for the sample size. An accurate and efficient method for the determination of soil organic matter content was established by high frequency infrared carbon-sulfur analyzer. RESULTS When the conditions set for a sample size of 0.05g, the flux iron content was 0.40g, and the tungsten content was 1.50g, optimum results of organic content were obtained. The method was verified by soil standard materials. The detection limit of this method was 0.003%, the relative standard deviation (RSD, n=7) was less than 4%, and the error between the analytical result and the standard value was less than 5%. There was no significant difference between the results of different analytical staff. The proposed method and potassium dichromate volumetric method were used to analyze soil samples in farm land of Gansu Province. The absolute error ranges of this method and potassium dichromate volumetric method were from -0.25% to 0.28%. The positively linear correlation between the determination results (R2=0.9736) indicated that the two methods were in good agreement. CONCLUSIONS The detection limit, precision and accuracy of the established method meet the requirements of the soil samples of farm land.

Accurately predicting the drift of spinning projectiles in the highland region has always been a challenging task. The study combines genetic algorithm, modified mass ballistic model, and data from ballistic tests to establish a computational model of projectile plateau drift, which is able to compute the value of projectile drift accurately. The reliability of the model was verified by the tests. The study also explains the reasons for the formation of projectile drift and the characteristics of plateau drift through theory. The results of the study proved that under the same range, the projectile's yaw of repose angle is larger in the plateau region, but its projectile plateau drift is smaller mainly because the flight time of the projectile on the highland is smaller than that on the plains. The results of the study are of great significance for the precision strike of projectiles in the highland area. [ABSTRACT FROM AUTHOR]