黄土不同湿度状态下动、静变形特性关系的探讨

从实用角度出发,对西安、兰州和太原3个典型黄土地区的原状黄土在不同湿度状态下所取得的动三轴振陷资料以及常规侧限压缩、湿陷试验的资料进行了统计分析,给出了黄土动、静力变形特性参数之间的相关关系,探讨了用常规的静力特性参数评估动力特性的可能性。     

COMPUTED TOMOGRAPHIC EVALUATION OF ANATOMIC AND PATHOLOGIC VARIATIONS IN THE FELINE NASAL SEPTUM AND PARANASAL SINUSES

The purpose of this study was to compare the prevalence of nasal septal deviation and variations of the paranasal sinuses in normal and diseased cats. Prevalence of nasal septal deviation was 86.7%, 68.4%, and 71.4% in cats with rhinitis, neoplasia, and normal cats, respectively, with no statistically significant difference (P = 0.244). There was a statistically significant difference (P = 0.01) in the magnitude of nasal septal deviation between cats with and cats without nasal disease, using a cutoff value of 1 mm for maximum distance of deviation from midline. There was a statistically significant difference (P = 0.019) between cats with rhinitis and neoplasia when comparing the presence of a mass (7.7% and 53.8%, respectively), but not when comparing for lysis of the septum. Deviation of the frontal sinus septum occurred in 27.7% of all cats, while the sphenoid septum was oblique and eccentric in 96.6% of all cats. The mean length of the frontal sinus was longer in male cats than female cats. The presence of nasal septal deviation alone cannot be used as a criterion to diagnose nasal disease, but cats with rhinitis or neoplasia have more marked deviation than normal cats. The presence of a mass and lysis of the septum were only seen in cats with nasal disease and a mass is more likely to be seen with neoplasia than rhinitis. Male cats have a longer frontal sinus than female cats. Almost all cats have an oblique, eccentric sphenoid septum.     

Numerical Simulation Research on Stabilityof Dissolving Cavityfor the Low-depth-thin-layer Rock Salt

In order to extend life of salt well, avoid sinking and use the formed cavity reasonably, the factors of effecton cavity stability must be researched during the process of water mining of rock salt, so that the effective prevention measures can be put. The stability of dissolving cavity for the low depth thin layer rock salt has been researched by the ADINA non linear finite element method.The results show that the stability of dissolving cavity obviously becomes strengthened with the decrease of its height, and has a decreasing trendas with the span increase of the cavity . The effect of incidence on stability of the cavity is very little. The stability of cylindroid cavity is higher than that of converse taper cavity. The assorted model is a kind of transition shape. The influencing order of cavity stability is the ffollows, height>geometrical shape>span>incidence.     

Theoretically Investigation of Dynamic Characteristics of Spherical Bubble Collapse in Pulsed Abrasive Water Jet

This paper theoretically investigates the characteristics of cavitating bubbles in the pulsed abrasive water jet(PAWJ) and establishes the dynamic equations of cavitating bubbles. The effects of abrasive diameter and density on the spherical bubble collapse are also analyzed. It is found that the change of abrasive diameter rarely affects the bubble collapse when the abrasive diameter and density are small whereas the smaller abrasive greatly blocks the bubble collapse when the abrasive diameter and density are comparably big. It is also shown that when the abrasive density is increased, the fluid viscosity rises, and the kinetic energy of the abrasives near the collapsed bubble is enhanced and meanwhile the intensity of cavitating erosion is weakened.     

Aerobic bacterial flora of the nasal cavity in Gulf of California sea lion (Zalophus californianus) pups

Nasal swab samples from clinically healthy California sea lions pups (Zalophus californianus) from six different reproductive rookeries in the Gulf of California were collected to determine the type and frequency of the representative aerobic bacterial microflora of their nasal mucosa. A total of 114 samples were examined and 100 bacterial isolates were identified and typified by microbiological and biochemical standard tests. Fifty four isolates corresponded to Gram positive bacteria (54%) and 46 isolates to Gram negative bacteria (46%). Fifteen bacterial genera were identified, including Micrococcus, Arcanobacterium, Corynebacterium, Moraxella, Neisseria, Escherichia, Kurthia, Acinetobacter, Staphylococcus, Brevibacillus, Bacillus, Klebsiella, Stenotrophomonas, Pseudomonas and Aeromonas. The most frequently isolated genera were Moraxella (24%), Micrococcus (18%), and Corynebacterium (15%). These results show the presence in the nasal cavity of sea lions of several microorganisms. Although considered part of the normal microflora, they may also be opportunistic pathogens for their hosts and may act as a potential natural sentinel of environmental changes.     

Structural Influencing Coefficient of Moment-Resisting Steel Frames Based on Equal Collapse Rule

In order to realize the performance target of “no collapse under rare earthquake” based on the seismic design according to structural influencing coefficient, three moment-resisting steel frames have been designed with similar probability of collapse in accordance with Chinese Seismic Code. The structural influencing coefficient of steel frames were determined through the incremental dynamic analysis method, and within equal collapse design rule. This paper proposed a method to define structural influencing coefficient can provide reference for determining the design seismic force of steel frame reasonably.     

Research on reliability evaluation model for frequency collapse of power grid

In order to comprehensively consider the possibility and the severity of frequency instability risk, this paper proposes the risk evaluation model and algorithm for frequency collapse of power grid. The uncertainties in generating dispatch, network topology and component outage are considered. The calculation method for system frequency variation is depicted while considering the active power deficiency arising from random failure of generating units, and then various probabilistic risk indices for frequency collapse are defined. The presented method can provide important reference information for evaluating the frequency collapse risk of power grid. The non-sequential Monte Carlo simulation-based results of IEEE-RTS79 show the correctness of the method.     

孤立原子和双模腔内原子之间的纠缠突然死亡研究

通过计算并发度和线性熵研究了初始处于纠缠态的两个两能级原子与双模场相互作用系统的纠缠动力学特性,讨论了原子初始纠缠度和腔场初始纠缠度对并发度的影响。结果表明,两原子之间的纠缠出现纠缠突然死亡(ESD)现象,纠缠死亡持续的时间长度和原子初始的纠缠度无关,然而依赖于腔场初始纠缠度;在整个时间演化过程中,两原子和腔场之间一直保持着纠缠状态。     

A novel treatment for dynamic laryngeal collapse associated with poll flexion: the modified checkrein

Reasons for performing the study: Dynamic laryngeal collapse (DLC) associated with poll flexion is a performance limiting dynamic upper airway disorder commonly diagnosed in Coldblooded trotters. An inspiratory obstruction occurs when affected horses are driven with tension on the reins, inducing poll flexion. To date, surgical treatment and conservative management have failed to improve racing performance in affected horses. Objectives: To test the efficacy of an external device, the modified checkrein, in limiting poll flexion, diminishing laryngeal collapse and improving airway mechanics when horses are driven on a treadmill with tension on the reins and test the hypothesis that the modified checkrein will limit poll flexion thereby improving endoscopic appearance of the larynx and reduce airway obstruction in harness racehorses affected with DLC. Methods: Fourteen Norwegian Coldblooded trotter (NCT) racehorses previously diagnosed with DLC associated with poll flexion exercised on a high‐speed treadmill at speeds that resulted in heart rate >200 beats/min. Upper airway videoendoscopy recordings, tracheal pressures and video recordings of the head and neck position were collected while horses exercised with the conventional checkrein on Day 1 and the modified checkrein on Day 2. Results: The modified checkrein successfully limited poll flexion as measured by no change in head position parameters between phases of no rein tension and phases of rein tension. Endoscopic scores were significantly improved (arytenoids cartilage collapse P<0.0001; vocal fold collapse P<0.0001) and tracheal peak inspiratory pressures were significantly less negative (P = 0.0162) when horses were fitted with the modified checkrein compared to the conventional checkrein. Conclusions and potential relevance: The modified checkrein successfully limited poll flexion and also prevented upper airway obstruction in NCT horses affected with DLC associated with poll flexion. The modified checkrein seems promising in offering a method of conservative management in harness racehorses affected with this disorder.     

枣裂果机制研究

采用浸水模拟降雨、石蜡制片和显微测量技术,以极易裂、中抗和极抗裂品种为材料,测量枣果表皮厚度、梗洼下空腔、果肉空腔和果肉细胞大小及其变化,探讨成熟期枣裂果机制。结果表明,不同裂果等级枣品种之间表皮厚度差异极显著,且极抗裂品种表皮最厚,极易裂品种最薄,中抗品种居中,表皮越厚越抗裂。不同裂果等级枣品种之间梗洼下空腔与枣果比率差异极显著,极抗裂品种比率最小(0.24%～0.26%),极易裂品种最大(0.62%),梗洼下空腔越小越抗裂。不同裂果等级枣品种之间果肉空腔大小差异极显著,极抗裂品种最小(3 380.82～3 879.12μm2),极易裂品种最大(9 300.49～10 809.86μm2),果肉空腔越小越抗裂。果肉细胞大小没有显著差异,但果肉细胞的吸水速显著不同,极易裂品种果肉细胞吸收最快,极抗裂品种最慢,中抗品种居中,果肉细胞吸水越慢越抗裂。这些研究表明枣果表皮厚度、梗洼下空腔、果肉空腔和果肉细胞的吸水速度共同决定了枣的裂果程度。