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1.
对于具有大面积玻璃围护结构的建筑中庭,由于太阳辐射强、室内空间大等问题,导致热环境的控制非常复杂。对于这类建筑的空调系统设计,计算流体力学(CFD)等数值模拟方法的应用有着广阔的发展前景,但已有的数值计算方法复杂,通用性差,仅能被少数计算流体力学领域专业研究人员所掌握,这一因素大大制约了数值模拟方法的在实际工程中的广泛应用。本文对相关数值模拟方法进行了分析和总结,建立了一套简单快速的并具有合理准确性的通用联合模拟方法,并开发出相应的联合模拟计算程序。通过将模拟计算结果与实验结果进行比较,该方法的准确性得到了验证,同时将该方法应用于中庭空调系统的优化设计,表明了其在实际工程应用中的可行性。  相似文献   
2.
Engineering decisions concerning the performance of existing structures must be made in the presence of uncertainties. The remaining capacity of corroded steel structures provides a good example of different aspects of uncertainty. These include: an unknown or partially known extent of damage; a variability in loading and an uncertain reserve of structural capacity depending on the mode of failure. The theory of structural reliability has been developed to provide a method of analysis for structural safety. In this paper, methods are proposed to compute the component reliability of corrosion-damaged steel members. The application of a recently developed theory called interval probability theory for system reliability is illustrated using the data obtained from actual samples of corroded beams.  相似文献   
3.
本文阐述低温热水地面辐射供暖设计中应注意的几个问题,供设计与应用时参考。  相似文献   
4.
The replacement of any limit state function by an equivalent linear function is discussed in detail and it is shown that there are several methods by which such an equivalence may be established. In the case of multiple failure mode problems the definition of fully equivalent linear functions requires the additional consideration of mode correlations. The manner in which this may be carried out is discussed and it is shown that, for most practical cases, a relatively simple analysis is likely to be sufficient to define the set of equivalent linear limit states, with the advantage that the established theory of such linear limit states may then be employed in the majority of reliability analyses.  相似文献   
5.
在辐射热源法检测卷材地板的过程中,一些因素对检测结果的影响较大,会直接影响到符合性的判定。本文在笔者数年卷材地板燃烧性能的检测基础上,对几个影响卷材地板燃烧性能测定结果的因素进行了分析探讨,并对个别因素的影响程度进行了试验论证,为各位试验人员提供一个借鉴。  相似文献   
6.
A low-dose gamma radiation phytosanitary treatment against the oriental fruit fly, Bactrocera dorsalis Hendel, was developed for guava fruits. The measure for efficacy of the treatment is preventing adult emergence from late third instars that were reared in the fruit of guava, Psidium guajava L. The dose–response tests with 1-, 2-, 3-, 7-d-old larvae in guava were initiated to determine the most tolerant stages, the late-aged third instars. No adult emerged from a total of 100,684 late-aged third instars irradiated at the dose of 97–116 Gy, resulting in an efficacy of 99.9970% at the 95% confidence level. The minimum dose for 100% preventing adult emergence from 2-, 5-, 7-d-old pupae (1800 pupae in each dose) reared in artificial diets was 100, 500, and 1750 Gy, respectively. Quality determinations on ‘Taiwan’ guavas were conducted at 1, 3 and 7 days after gamma radiation at doses of 200, 400, 600, 800, 1,200, 2000 and 6000 Gy. The guavas could tolerate radiation dose up to 600–800 Gy as there were no significant changes in organoleptic characteristics (≤800 Gy), the chemical and nutritional contents (sugar, sucrose, total sugar, titratable acid, vitamin C, and soluble solid) (≤600 Gy). Therefore, a dose of 116 Gy, which give the disinfestations efficacy of 99.9968% for the late-aged larvae in guavas and 100% mortality of 2-d-old pupae, is suggested as the minimum absorbed dose for phytosanitary irradiation treatment of B. dorsalis in fruits.  相似文献   
7.
采用6种钴60辐照剂量(0、2、4、6、8、10 k Gy)处理鸡蛋卵清蛋白(OVA),并探明辐照技术对卵清蛋白结构和抗氧化性的影响。以新鲜鸡蛋为原料,经0、2、4、6、8、10 k Gy 6种钴60辐照剂量处理;硫酸铵沉淀法提取卵清蛋白;并测定不同辐照条件下卵清蛋白溶解度、自由巯基含量、内源性荧光、还原力、DPPH自由基清除率的变化。实验结果表明:辐照对于卵清蛋白的结构和理化性质影响较大,随着辐照剂量的增加,OVA的可溶性蛋白含量、自由巯基含量、DPPH清除能力和还原力,均有不同程度的提高;内源荧光呈现先上升后下降趋势,当辐照剂量为10 k Gy时,内源荧光值显著低于对照组(p<0.05)。此研究为辐照卵清蛋白产品的工业应用提供了理论依据。   相似文献   
8.
Protein arginine methyltransferase 5 (PRMT5) is an epigenetic regulator which has been proven to be a potential target for cancer therapy. We observed that PRMT5 underwent alternative splicing (AS) and generated a spliced isoform PRMT5-ISO5 in hepatocellular carcinoma (HCC) patients after radiotherapy. However, the regulatory mechanism and the clinical implications of IR-induced PRMT5 AS are unclear. This work revealed that serine and arginine rich splicing factor 3 (SRSF3) silencing increased PRMT5-ISO5 level, whereas heterogeneous nuclear ribonucleoprotein H 1 (HNRNPH1) silencing reduced it. Then, we found that SRSF3 and HNRNPH1 competitively combined with PRMT5 pre-mRNA located at the region around the 3′- splicing site on intron 2 and the alternative 3′- splicing site on exon 4. IR-induced SRSF3 downregulation led to an elevated level of PRMT5-ISO5, and exogenous expression of PRMT5-ISO5 enhanced cell radiosensitivity. Finally, we confirmed in vivo that IR induced the increased level of PRMT5-ISO5 which in turn enhanced tumor killing and regression, and liver-specific Prmt5 depletion reduced hepatic steatosis and delayed tumor progression of spontaneous HCC. In conclusion, our data uncover the competitive antagonistic interaction of SRSF3 and HNRNPH1 in regulating PRMT5 splicing induced by IR, providing potentially effective radiotherapy by modulating PRMT5 splicing against HCC.  相似文献   
9.
Plasmid DNA is useful for investigating the DNA damaging effects of ionizing radiation. In this study, we have explored the feasibility of plasmid DNA-based detectors to assess the DNA damaging effectiveness of two radiotherapy X-ray beam qualities after undergoing return shipment of ~8000 km between two institutions. The detectors consisted of 18 μL of pBR322 DNA enclosed with an aluminum seal in nine cylindrical cavities drilled into polycarbonate blocks. We shipped them to Toronto, Canada for irradiation with either 100 kVp or 6 MV  X-ray beams to doses of 10, 20, and 30 Gy in triplicate before being shipped back to San Diego, USA. The Toronto return shipment also included non-irradiated controls and we kept a separate set of controls in San Diego. In San Diego, we quantified DNA single strand breaks (SSBs), double strand breaks (DSBs), and applied Nth and Fpg enzymes to quantify oxidized base damage. The rate of DSBs/Gy/plasmid was 2.8±0.7 greater for the 100 kVp than the 6 MV irradiation. The 100 kVp irradiation also resulted in 5±2 times more DSBs/SSB than the 6 MV beam, demonstrating that the detector is sensitive enough to quantify relative DNA damage effectiveness, even after shipment over thousands of kilometers.  相似文献   
10.
The conformational heterogeneity of the p53 tumor suppressor, the wild-type (p53wt) and mutated forms, was investigated by a computational approach, including the modeling and all atoms of the molecular dynamics (MD) simulations. Four different punctual mutations (p53R175H, p53R248Q, p53R273H, and p53R282W) which are known to affect the DNA binding and belong to the most frequent hot-spot mutations in human cancers, were taken into consideration. The MD trajectories of the wild-type and mutated p53 forms were analyzed by essential dynamics to extract the relevant collective motions and by the frustration method to evaluate the degeneracy of the energy landscape. We found that p53 is characterized by wide collective motions and its energy landscape exhibits a rather high frustration level, especially in the regions involved in the binding to physiological ligands. Punctual mutations give rise to a modulation of both the collective motions and the frustration of p53, with different effects depending on the mutation. The regions of p53wt and of the mutated forms characterized by a high frustration level are also largely involved in the collective motions. Such a correlation is discussed also in connection with the intrinsic disordered character of p53 and with its central functional role.  相似文献   
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