制动防抱死系统在汽车上的应用

在文中通过研究汽车制动时的受力情况、路面附着特性、制动防抱死系统的控制方式、组成和工作情况，得出了使车轮滑动率保持在20％的最佳状态可提高汽车的制动效能，缩短制动距离。并使汽车具有较好的转向和抵抗侧向力的作用，提高汽车制动时的方向稳定性的结论。     

手动比例复合阀在中高压液压绞纲机中的应用

中高压液压技术在海洋捕捞机械—绞纲机中的使用推动了我国渔业机械的发展,手动比例复合阀在中高压液压技术上的应用则大大加快了液压绞纲机在国内渔业生产中的普及。目前,我国浙江、江苏、福建、广东和山东等省沿海渔民使用的绞纲机普遍采用带手动比例复合阀的液压系统。为此,对手动比例复合阀换向、溢流、调速集成等功能进行了分析。     

Scale of heterogeneity of forage production and winter foraging by elk and bison

The relationship between fine-scale spatial patterns of forage abundance and the feeding patterns of large ungulates is not well known. We compared these patterns for areas grazed in winter by elk and bison in a sagebrush-grassland landscape in northern Yellowstone National Park. At a fine scale, the spatial distribution of mapped feeding stations in 30 m × 30 m sites was found to be random where there were no large patches devoid of vegetation. In areas similar to the mapped sites, the underlying spatial distribution pattern of biomass was also determined to be random. At a broad scale, forage biomass differed among communities across the northern range but forage quality did not. These results suggest that ungulates are feeding randomly within forage patches (fine scale) but may select feeding sites based upon forage abundance at broader, landscape scales. Contrary to what has been suggested in other systems, ungulates were not overmatching at finer scales.     

Suppression of wheat-seedling diseases caused by Fusarium culmorum and Microdochium nivale using bacterial seed treatment

Snow mould, caused by Microdochium nivale , and seedling blight caused by members of the Fusarium complex, are cereal diseases of great economic importance in many temperate zones. In a glasshouse bioassay designed to enhance disease, about 600 plant-associated bacterial isolates obtained by different methods were screened for suppressive effects in wheat against infection caused by Fusarium culmorum . Although most of the isolates tested had a neutral effect on test plants and disease development, a few were synergistic to the pathogen and about one-fifth showed > 80% disease suppression. During five consecutive growing seasons, 164 bacterial isolates were tested in field experiments against both F. culmorum and M. nivale as causal agents of seedling blight. Tests for effects on yield in experiments with spring and winter wheat, performed in different climatic regions of Sweden, showed that disease-suppressive effects were repeatable. The most efficient isolates, three fluorescent pseudomonads and a species of Pantoea , suppressed disease equal to that of the fungicide guazatine, both with respect to crop stand and yield. Seed treatment with Pantoea sp. (isolate MF 626) increased yield by an average of more than 500 kg ha⁻¹ in six field experiments.     

Osmolarity,cell volume and proliferation in nasopharyngeal carcinoma cells

AIM: To investigate the relationship between osmolarity, cell volume and cell proliferation in nasopharyngeal carcinoma cells. METHODS: MTT method was applied to detect the proliferation ability of the poorly-differentiated nasopharyngeal carcinoma cell (CNE-2Z) under various osmolarity conditions. The flow cytometry was used to analyse cell cycle distribution. Cell volume was obtained by the image analysis of living cells and cell viability was determined by the trypan blue assay. RESULTS: Cultivation of cells under the hypertonic conditions of 370 and 440 mOsmol/L increased cell volume by 8.7% and 27.8% and facilitated cell proliferation by 22.2% and 33.9%, respectively. However, hypotonic incubation of cells with osmolarity of 160 and 230 mOsmol/L decreased cell volume by 12.8% and 4.1% and inhibited cell proliferation by 34.0% and 15.6%, respectively. Cell volume was positively correlated with cell proliferation rate. Long-term cultivation of cells under anisotonic conditions did not significantly alter cell cycle distribution, but hypotonic cultivation decreased cell viability. CONCLUSION: Proliferation of nasopharyngeal carcinoma cells was closely correlated with the osmolarity of culture medium and cell volume. Hypotonic cultivation may inhibit cell proliferation by decreasing cell volume to facilitate cell death mechanisms.     

Efficacy of a mephentermine‐based product as a vasopressor and a cardiac performance enhancer when given intramuscularly to cattle

The goal of this study was to confirm the vasopressor and cardiac effects of POTENAY^® INJETÁVEL (POT), a mephentermine‐based product, given to cattle with induced vascular/cardiac depression. Ten healthy Holstein cattle (206 ± 13 kg) followed a randomized‐complete‐block design (RCBD) utilizing crossover study design. Each animal randomly received (1 ml/25 kg, IM) of either POT (n = 10) or volume‐matched placebo control (0.9%NaCl, CP, n = 10). A subset of animals (n = 5) received POT first (day 0) while the remaining (n = 5) received CP; after a six‐day washout period, cattle received the opposite compound. Animals were anesthetized and catheterized for systemic/left ventricular hemodynamic monitoring. Myocardial dysfunction/hypotension was induced by increasing the end‐tidal isoflurane concentration until arterial blood pressure was 20% lower than at baseline and remained stable. Once the animal was determined to be hypotensive and hemodynamically stable, steady‐state hypotensive baseline data (BL2) were acquired, and treatment with either POT or CP was given. Data were acquired post‐treatment at every 15 min for 90 min. POT improved cardiac output (+68 L/min, ±14%, p < 0.05), MAP (+14 mmHg, ±4%, p < 0.05), HR (+22 bpm, ±8%, p < 0.05), and peak rates of ventricular pressure change during both systole (dP/dt_max: +37 mmHg/s ±13%, p < 0.05) and diastole (dP/dt_min: +31 mmHg/s, ±7%, p < 0.05). No improvements were noted following placebo‐control administration. Results indicate that POT improves cardiac performance and systemic hemodynamics in cattle with induced cardiovascular depression when given as single intramuscular injection.     

高层建筑分层供暖系统

如何解决高层建筑供暖系统分区问题是建筑供暖函待解决的问题,本文针对此问题介绍了四种适合不同系统情况下的具体方式,并且阐述了四种方式的工作原理及所适合的系统.     

试论安装管道阀门的重要性

本文论述了如何了解阀门特性,选择管道系统最适合安装的阀门产品,掌握选择阀门步骤和依据.     

淡干海参泡发工艺研究

为探究淡干海参泡发工艺,以烟台淡干海参为原料,通过正交试验得到最优工艺条件为：121 ℃、0.12 MPa高温高压处理20 min,全程使用蒸馏水,泡发温度4 ℃,泡发时间48 h,采用该工艺泡发的海参质量和长度分别为泡发前干海参的14.5倍和2.7倍,复水比为9.2,其硬度、弹性、适口性、持水力及营养价值均高于市面上常压煮制常温泡发的海参。该研究结果为科学、方便地食用和推广淡干海参提供了理论依据。     

Inducible nitric oxide synthase and arterial pressure regulation

AIM and METHODS:To clarify the role of inducible nitric oxide synthase (iNOS) in the regulation of blood pressure,in the present study, we examined the effect of aminoguanidine (AG), a selective inhibitor of iNOS on the hemodinamical response of Dahl salt-sensitive (DS) and Dahl salt-resistant (DR) rats to low (0.3%) or high (8%) sodium chloride (NaCl) infusion by chronical in vivo hemodynamic experiment, and the effect of NaCl or NaCl plus AG infusion on urinary nitrate (NO₃)/nitrite (NO₂), the end product of nitric oxide (NO), excretion by Greiss Reaction. Furthermore, NOS activity assay was also carried out to probe the effect of NaCl and AG on calcium-dependent or independent NOS activity in renal tissue. RESULTS:1. High or low NaCl-infused DR rats and low NaCl-infused DS rats have no hemodinamical response to AG, however, the hypertensive effect of high NaCl (8%) infusion on DS rats were greatly amplified by co-infusion of AG. 2. Administration of high NaCl significantly elevated the iNOS activity of renal tissue, and greatly increased urinary NO₃/NO₂ excretion. CONCLUSION:Inducible NOS is an important modulator of arterial pressure, especially in case of higher blood pressure.