直接拟设法解广义Burgers-Huxley方程

通过引进一个合适的拟设方程和直接拟设法得到广义Burgers-Huxley方程的显示精确孤波解,同时也可以通过这种方法得出广义Burgers-Huxley方程的一些特殊形式的方程。     

浅议开关电源的干扰源

开关电源由于其在体积、重量、功率密度、效率等方面的诸多优点,已经被广泛地应用于工业、国防、家用电器等各个领域。随着开关电源工作频率的不断提高,印制电路板的走线和元件的布局不当等原因。所产生的电磁干扰和低频噪声辐射将会对周围环境以及存在于周围空间中的设备、仪器带来危害。了解开关电源的干扰源,可以方便设计人员采取有效的措施来降低开关电源的干扰程度和提高其抗干扰的能力。     

钢管混凝土超声波检测试验

阐述了超声波检测钢管混凝土质量的基本原理，以及带有各种缺陷的钢混凝土试件的制作方法及试件的测试程序。给出了部分试件的实测声学参数和波形。并通过实测波形和声学参数的分析，总结出超声波在带有多种缺陷的钢混凝土中传播时波形和声学参的变化规律，可供采用超声波检测钢混凝土地质量时参考。     

Wireless Soil Scout prototype radio signal reception compared to the attenuation model

Wireless underground Soil Scout prototypes, introduced here for the first time, were used for remote soil monitoring during 5 months in real conditions. Every Soil Scout transmitted moisture and temperature data once every 10 min. The prototype system works well. A signal attenuation model is able to predict long periods of lost signals when soil moisture and on-soil vegetation conditions change. The model attenuation −98 dB is the threshold level for distinguishing probable failure from success, even if the system hardware design would suggest −110 dB. Individual transmission failures do not always correlate to changes of condition. Further work should focus on increasing transmission power and improving knowledge of the effect of vegetation.     

太平湖水库防浪墙裂缝成因及防治措施探讨

本文分析了太平湖水库防浪墙上的裂缝成因，如混凝土干缩、防浪墙基础对墙身的约束作用等，并提出了避免防浪墙开裂的工程措施。     

Green color protection of bamboo culms using one-step alkali pretreatment-free process

This study evaluated the protection effectiveness of alcohol-borne reagents for the green color of ma bamboo (Dendrocalamus latiflorus Munro) and moso bamboo (Phyllostachys pubescens Mazel). The results show that the types and concentrations of alcohol-borne reagents, the kinds of solvent, and the conditions of treatment greatly affected the green color of these two bamboo species. Without alkali pretreatment, an excellent green color protection (a* = −14.5) was obtained when the ma bamboo culms were treated with 0.5% methanol-borne copper chloride (CuCl₂) at 60°C for 30 min. Similar results were also obtained when ma bamboo culms were treated with 0.5% methanol-borne copper nitrate [Cu(NO₃)₂] at 60°C for 2 h (a* = −13.5). For moso bamboo, an attractive green color in the bamboo culms was achieved by treating the specimens with 1% methanol-borne copper acetate [Cu(CH₃COO)₂] at 60°C for 30 min. The a* value of treated specimens was −13.3. In addition, results demonstrated that ultrasonic treatment was more effective on green color protection than conventional water bath treatment. When moso bamboo was treated with 1% copper acetate at 60°C in an ultrasonic bath for only 15 min, a remarkable green color with an a* value of −13.6 was obtained on the bamboo epidermis.     

健康黑松幼苗中的电波传递

以健康黑松(Pinus thunbergii)幼苗为材料,用非伤害性刺激,如冷冻和伤害性刺激,如：烧伤、刺伤、化学伤害等引发了植物体内的波形的变化,研究表明,非伤害性刺激能在幼苗体内引起动作电波的传递,伤害性刺激除了能引起动作电波的传递外,还能引起较为复杂的变异电波的传递并对这种现象进行了讨论。图4参28。     

Decay Detection of Ancient Wood Rafters in Tibet by Stress Wave Testing Method

Visual classification and stress wave non-destructive testing technology were adopted to evaluate the decay status of ancient Populus wood members （rafters） replaced from the Potala Palace. The decay status of wood members was evaluated by stress wave testing and visual observation. For most of the ancient wood members, the evaluation results by two methods were consistent with each other. Also stress wave testing techniques can find the internal wood member decay to eliminate the hidden hazard for ancient wood members, and offer relatively accurate quantitative information for the safety status of ancient wood members. Thus during the maintaining for ancient architectures, visual observation combined with stress wave testing techniques is a good way to evaluate the degradation of ancient wood members.     

Accessory corpora lutea formation in pregnant Hokkaido sika deer (Cervus nippon yesoensis) investigated by examination of ovarian dynamics and steroid hormone concentrations

Generally, sika deer conceive a single fetus, but approximately 80% of pregnant females have two corpora lutea (CLs). The function of the accessory CL (ACL) is unknown; moreover, the process of ACL formation is unclear, and understanding this is necessary to know its role. To elucidate the process of ACL formation, the ovarian dynamics of six adult Hokkaido sika deer females were examined ultrasonographically together with peripheral estradiol-17β and progesterone concentrations. ACLs formed in three females that conceived at the first estrus of the breeding season, but not in those females that conceived at the second estrus. After copulation, postconception ovulation of the dominant follicle of the first wave is induced by an increase in estradiol-17β, which leads to formation of an ACL. A relatively low concentration of progesterone after the first estrus of the breeding season is considered to be responsible for the increase in estradiol-17β after copulation.     

Experimental study on the effect of horizontal waves on netting panels

The effect of horizontal waves on flexible netting panels is examined in this study, to evaluate the testing method of pretensioned mooring, radial systems, and flexible netting structures. The netting was suspended at a specific hanging ratio for six polyethylene panels with different characteristics. The aim was to evaluate the calculation method for horizontal wave forces on flexible netting panels. A regular wave was used in the experiment, with wave period 0.8–2.0 s and wave height 50–250 mm. The force on the netting structure was recorded by a tension transducer and digital signal recorder, and was simulated by a cubic spline in terms of the wave experiment under different wave conditions. The horizontal wave force on the netting panel changed periodically and asymmetrically, which was similar to the surface wave elevation. The horizontal wave force was related to the netting panel height and width (l), wave height (H) and wave length (L), twine diameter (d) and bar length (a) of the mesh. Using dual series relations, least-squares approximation, and multiple stepwise regression analysis, the following formula was obtained for the horizontal wave average apex value (F) on the netting panel: F=0.13ρgl(H/2)²(d/a)(H ^0.64 L ^0.77/0.9a ^0.44).