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101.
中压型大功率电子束焊机电控系统的研制 总被引:5,自引:3,他引:5
本文介绍了70kV、30kW电子束焊机电子枪电源──加速电源、灯丝电源、轰击电源和偏压电源的特点及其控制原理。 相似文献
102.
为研究包覆方式对片状发射药燃烧性能的影响,建立了不同包覆方式下多层片状发射药的物理模型,并推导了形状函数和燃气生成猛度表达式,利用Matlab软件对不同的宽厚比、长厚比及多层结构的片状发射药进行了数值计算;制备了不同长厚比的片状变燃速发射药,并进行了密闭爆发器实验。结果表明,四面包覆和全包覆可以很好地消除临界宽厚比对片状发射药燃烧性能的影响;与两面包覆的片状发射药相比,四面包覆和全包覆的片状发射药能够延缓内层药减面燃烧的时间,其燃气生成猛度的阶跃程度分别提高了1.17%和1.23%,呈现出良好的燃烧渐增性。 相似文献
103.
采用等离子熔覆法在Mn13高锰钢上制备了低碳Fe-Ni合金层。以熔覆电流、喷头移动速率、离子气流量和热处理温度作为输入参数,以冲击韧性作为输出参数,建立了BP(误差反向传播)神经网络模型和粒子群算法优化(PSO)BP神经网络模型,并跟冲击韧性与热处理温度之间的线性回归模型进行对比。结果表明,线性回归模型、BP神经网络模型和PSO-BP模型的平均相对误差分别为7.06%、6.12%和3.03%。PSO-BP模型的预测结果与实测值的误差较小。 相似文献
104.
Xiuhong Li Bin Zhang Pengda Ma Ruizhi Cao Xiaobing Yang Juane Dong 《International journal of molecular sciences》2021,22(7)
Salvia miltiorrhiza Bunge has been widely used in the treatment of cardiovascular and cerebrovascular diseases, due to the pharmacological action of its active components such as the tanshinones. Plasma membrane (PM) H+-ATPase plays key roles in numerous physiological processes in plants. However, little is known about the PM H+-ATPase gene family in S. miltiorrhiza (Sm). Here, nine PM H+-ATPase isoforms were identified and named SmPHA1–SmPHA9. Phylogenetic tree analysis showed that the genetic distance of SmPHAs was relatively far in the S. miltiorrhiza PM H+-ATPase family. Moreover, the transmembrane structures were rich in SmPHA protein. In addition, SmPHA4 was found to be highly expressed in roots and flowers. HPLC revealed that accumulation of dihydrotanshinone (DT), cryptotanshinone (CT), and tanshinone I (TI) was significantly reduced in the SmPHA4-OE lines but was increased in the SmPHA4-RNAi lines, ranging from 2.54 to 3.52, 3.77 to 6.33, and 0.35 to 0.74 mg/g, respectively, suggesting that SmPHA4 is a candidate regulator of tanshinone metabolites. Moreover, qRT-PCR confirmed that the expression of tanshinone biosynthetic-related key enzymes was also upregulated in the SmPHA4-RNAi lines. In summary, this study highlighted PM H+-ATPase function and provided new insights into regulatory candidate genes for modulating secondary metabolism biosynthesis in S. miltiorrhiza. 相似文献
105.
María A. Vasco-Mogorrn Jos A. Campillo Adela Periago Valentin Cabaas Mercedes Berenguer María C. García-Garay Lourdes Gimeno María F. Soto-Ramírez María D. Martínez-Hernndez Manuel Muro Alfredo Minguela 《International journal of molecular sciences》2021,22(8)
Proliferation and apoptosis of neoplastic cells are prognostic biomarkers in plasma cell neoplasms (PCNs). The prognostic capacity of proliferation to apoptosis ratio (Ratio-PA) in the era of immunomodulatory treatments is re-evaluated in 316 gammopathy of undetermined significance (MGUS), 57 smoldering multiple myeloma (SMM), and 266 multiple myeloma (MM) patients. Ratio-PA of 0.77 ± 0.12, 1.94 ± 0.52, and 11.2 ± 0.7 (p < 0.0001) were observed in MGUS, SMM, and MM patients. Ten-year overall survival (10y-OS) rates for patients with low/high Ratio-PA were 93.5%/77.3% p < 0.0001) for MGUS, 82.5%/64.7% (p < 0.05) for SMM, and 62.3%/47.0% (p < 0.05) for MM. For patients with low, intermediate, and high risk, 10y-OS for low/high Ratio-PA were 95.5%/72.9% (p < 0.0001), 74.2%/50.4% (p < 0.0001), and 35.3%/20.0% (p = 0.836), respectively. Ratio-PA was an independent prognostic factor for OS (HR = 2.119, p < 0.0001, Harrell-C-statistic = 0.7440 ± 0.0194) when co-analyzed with sex, age, and standard risk. In patients with Ratio-PAhigh, only first-line therapy with VRd/VTd, but not PAD/VCD, coupled with ASCT was associated with high 10y-OS (82.7%). Tumor cell Ratio-PA estimated at diagnosis offers a prognostic biomarker that complements standard risk stratification and helps to guide the clinical management of pre-malignant and symptomatic PCNs. Every effort should be made to provide first-line therapies including VTd or VRd associated with ASCT to patients with Ratio-PAhigh at higher risk of progression and death. 相似文献
106.
Nuchanart Suealek Thipaporn Tharavanij Robert M. Hackman Carl L. Keen Roberta R. Holt Benjapun Burawat Ammara Chaikan Rattana Tiengtip Panadda Rojpibulstit 《European Journal of Lipid Science and Technology》2021,123(2):2000126
The potential cardiovascular benefit of virgin olive oil (VOO) is widely recognized. However, the use of VOO at very high cooking temperatures makes these oils poorly suited for many Asian dishes. The use of tea seed oil (TSO) is increasing in Thailand, with TSO having a higher smoke point than VOO. The current study examines the effects of daily TSO intake in healthy adults. In a randomized, single-blind crossover design, 12 men consumed for 3 weeks 40 g day−1 of food prepared with either TSO or VOO as a cooking oil. Plasma lipids, thiobarbituric acid reactive substances (TBARS), and oxidant defense enzyme activities are measured before and after each 3-week intervention period. Gas chromatography analysis of TSO and VOO demonstrates that both oils are equally high in monounsaturated fatty acid. The dietary incorporation of TSO and VOO for three weeks reduces low-density lipoprotein cholesterol (LDL-C) concentrations by 15% and 13%, respectively; with total cholesterol (TC) levels lowered by 10% in both groups. No significant changes in TBARS or antioxidant enzyme activity is observed. These results support the concept that Thai TSO can be utilized as a suitable and healthy alternative oil for high-temperature cooking in many Thai and Asian diets. Practical Applications: Tea seed oil from Camellia oleifera grown in Thailand has been recently reported to favorably lower lipid profiles in hamsters fed a high-fat diet in a manner similar to feeding refined olive oil or grapeseed oil. A pilot crossover trial is conducted to compare the effects of three weeks of daily intake of either TSO or VOO in healthy human adults. Consumption of both oils produced significant reductions in TC and LDL-C. Thai TSO leads to favorable lipid profiles and is a reasonable choice for many Thai and Asian food recipes. 相似文献
107.
Zewen Chen Zhenhua Wang Boxiang Wang Juntang Yuan Lei Huang Zengbin Yin 《International Journal of Applied Ceramic Technology》2021,18(6):2010-2019
In this study, WC-8Co cemented carbides were prepared by spark plasma sintering. When the samples sintered at 1300℃ were cooled to room temperature, the samples were sintered multiple times at 1250℃. The changes in microstructure and mechanical properties of WC-8Co cemented carbides prepared by multiple spark plasma sintering were studied. The hardness of cemented carbides increased in the first two sintering, reaching 16.5 GPa. However, the hardness decreased seriously in the last two sintering. The attenuation rates of hardness were 6.2% and 2.5% due to the abnormal coarse grains. Furthermore, the crack path along the grain boundary was almost straight, causing a decrease in the indentation fracture toughness of cemented carbides. Additionally, the grains of cemented carbides were abnormally coarsened, and the morphologies of grains became unstable due to multiple sintering. 相似文献
108.
G. Antou F. Hlawka A. Cornet G. Montavon C. Coddet F. Machi 《Journal of Thermal Spray Technology》2004,13(3):381-389
Several studies have been undertaken recently to adapt yttria partially stabilized zirconia (YPSZ) thermal barrier coating
(TBC) characteristics during their manufacturing process. Thermal spraying implementing laser irradiation appears to be a
possibility for modifying the coating morphology. This study aims to present the results of in situ (i.e., simultaneous treatment)
and a posteriori (i.e., post-treatment) laser treatments implementing a high-power laser diode. In both cases, the coatings
underwent atmospheric plasma spraying (APS). Laser irradiation was achieved using a 3 kW, average-power laser diode exhibiting
an 848 nm wavelength. Experiments were performed to reach two goals. First, laser post-treatments aimed at building a map
of the laser-processing parameter effects on the coating microstructure to estimate the laser-processing parameters, which
seem to be suited to the change into in situ coating remelting. Second, in situ coating remelting aimed at quantifying the
involved phenomena. In that case, the coating was treated layer by layer as it was manufactured. The input energy effect was
studied by varying the scanning velocity (i.e., between 35 and 60 m/min), and consequently the irradiation time (i.e., between
1.8 and 3.1 ms, respectively). Experiments showed that coating thermal conductivity was lowered by more than 20% and that
coating resistance to isothermal shocks was increased very significantly. 相似文献
109.
Ti3SiC2 materials have been fabricated by spark plasma sintering of the elemental powders with the addition of Al.At the heating rate of 80℃/min and under the pressure of 30MPa,the ideal synthesis temperature of Ti3SiC2 is in the range of 1150-1250℃.The addition of Al is in favor of the formation of Ti3SiC2.The synthesized compound has the molecular of Ti3Si0.8Al0.2C2 and lattice parameters of α=0.3069nm,c=1.7670nm.Its grain is plane-shape with a size of about 50μm in the elongated dimension.The prepared material has Vickers hardness of 3.5-5.5GPa(at 1N and 15s) and is as readily machinable as graphite‘s. 相似文献
110.
准确、快速地测定含铁尘泥中有害元素,对含铁尘泥节能降废项目研究及综合利用有着重要的指导意义。实验针对含铁尘泥试样因含碳量高,导致常规酸溶解方法如果不增加除碳步骤则很难完全分解试样的问题,采用高温熔融法将试样制成熔融液后倾倒于稀酸中溶解的方法,解决了碳含量高难溶解的问题。采用四硼酸锂-碳酸锂混合熔剂在高温下将试样熔融,熔融液高温倾倒于稀酸中制成澄清溶液,由于骤冷,试样炸裂成微小玻璃珠,无迸溅,操作简单,使得后续溶解过程快速完成,从而建立了电感耦合等离子体原子发射光谱(ICP-AES)测定P、Pb、K、Na、Zn共5种有害元素的方法。按照实验方法测定含铁尘泥中P、Pb、K、Na、Zn,测定值的相对标准偏差(RSD,n=9)在1.4%~5.7%之间,加标回收率在96%~110%之间。研究结果表明方法能够满足含铁尘泥样品中5种元素的定量分析要求。 相似文献