The Influence of the Corrosion Product Layer Generated on the High Strength Low-Alloy Steels Welded by Underwater Wet Welding with Stainless Steel Electrodes in Seawater

The high strength low-alloy steels are welded by underwater wet welding with stainless steel electrodes. The microstructural and electrochemical corrosion study of base metal(BM), weld zone(WZ) and heat affected zone(HAZ) are carried out to understand the influence of the corrosion product layer generated on the high strength low-alloy steels welded by underwater wet welding with stainless steel electrodes, methods used including, potentiodynamic polarization, electrochemical impedance spectroscopy(EIS) and scanning electron microscope(SEM). The results indicate that the WZ acts as a cathode and there is no corrosion product on it throughout the immersion period in seawater. The HAZ and BM acts as anodes. The corrosion rates of the HAZ and BM change with the immersion time increasing. In the initial immersion period, the HAZ has the highest corrosion rate because it has a coarse tempered martensite structure and the BM exhibites a microstructure with very fine grains of ferrite and pearlite. After a period of immersion, the BM has the highest corrosion rate. The reason is that the corrosion product layer on the HAZ is dense and has a better protective property while that on the BM is loose and can not inhibit the diffusion of oxygen.

Effects of Magnesium and Ferric Ions on Crystallization of Calcium Sulfate Dihydrate Under the Simulated Conditions of Wet Flue-gas Desulfurization

The influences of magnesium and ferric ions in their different ratios on the rate of gypsum crystallization were studied under the conditions similar to those of wet flue-gas desulfurization（WFGD）. The results show that addition of both Mg^2＋ and Fe^3＋ increased induction time and decreased the growth efficiency up to 50% compared with the baseline（without impurities） depending on the concentration and the type of impurity. The effects of Mg^2＋ and Fe^3＋ on the surface energy and the rate of nucleation were estimated by employing the classical nucleation theory. The surface energy decreased by 8% and 14% with the addition of 0.02 mol/L magnesium or ferric ions, respectively, compared to the baseline. Mg^2＋ and Fe^3＋ made the growth rate of the （020）, （021） and （040） faces of gypsum crystal a much greater reduction, which leads to the formation of needle crystals compared to the baseline which favors the formation of plate or flakes. Furthermore, an edge detection program was developed to quantify the effects of impurities on the filtration rate of gypsum product. The results show that the inhibition efficiency of the presence of 0.02 mol/L Mg^2＋ and Fe^3＋ on the filtration rate of gypsum crystal ranges from 22% to 39%.

Hydrodynamics of the Pilot Scale Wet Scrubber with Restricted Outlet Absorbent Flow Rate

This paper presents the hydrodynamics of the wet scrubber coupled to a pilot CFB incineration facility. The scrubber was operated using tap water as a scrubbing liquid. The outlet liquid flow rate, Qo, and accumulation rate, Qa, strongly depend on the inlet liquid flow rate, Qin, with different profiles. At higher Qin values, Qo stabilizes, leading to higher Qa and finally flooding. The values of Qa were higher than Qo except for Qin ranging between 0.53 and 0.72 L/s (safe operating range) in which Qa ≌ Qo and Qa = Qin/2. The outlet-to-inlet liquid flow rate ratio, Qo/Qin decreased for Qin > 0.53 L/s. The increase in the accumulation-to-inlet liquid flow rate ratio, Qa/Qin, at higher Qin indicates a change in flow regime towards flooding, accompanied by an abrupt increase in the height of accumulating liquid, Ha. The difference between Qa/Qin and Qo/Qin (denoted as, ΔQao/Qin), shows a minimum close to zero in the safe operating range. The gas flow rate towards the wet scrubber had slight effect on Qo and Qa when Qin was maintained constant. The ratio Qo/Qin decreased slightly with Ha/Ht irrespective of gas velocity. Changing the liquid-to-gas ratio, L/G and Qin strongly affects the maximum and minimum values of Qo/Qin and Qa/Qin.

Wet Air Oxidation of Organic Wastewater Catalyzed by Doped Ceria

The catalytic wet air oxidation (CWAO) of H acid and phenol was investigated in the presence of Cu or Fe doped CeOsolid solutions, which were obtained by sol-gel method. The experiment results showed that the incorporation of Cu or Fe into the fluorite lattice of CeOstrongly enhanced the oxidation activity of the catalyst. At 90 ℃ and 0.1 MPa, H acid conversion was 70% for the Ce0.9Fe0.1O2-δ and 60% for the Ce0.9Cu0.1O2-δ catalyst. For phenol removal, the conversion was 70% for the Ce0.9Cu0.1O2-δ catalyst, while for the Ce0.9Fe0.1O2-δ the conversion was 30%. The results indicated that Ce0.9Cu0.1O2-δ was suitable for the treatment of organic wastewaters while Ce0.9Fe0.1O2-δ was suitable for the removal of H acid. The 70% phenol removal rate with Ce0.9Cu0.1O2-δ catalyst was markedly increased to 90% with Ce0.8Cu0.2O2-δ catalyst. However, the phenol removal reduced from 30% to 15% with Fe content increasing from 10% to 20%. For the H acid, the increase of the content of Cu or Fe tended to obviously increase the original reaction rate while the COD removal changed little.

Experimental Study on Treatment of Ammonia Nitrogen in Landfill Leachate Flowing from MBR Using Catalytic Wet Peroxide Oxidation

Active iron catalysts with 5A molecular sieve as the carrier were prepared firstly, and then were used in the treatment of ammonia nitrogen in landfill leachate pretreated by MBR by using CWPO, finally the effects of preparation process of catalysts, assistants and reaction conditions on the removal rate of ammonia nitrogen were analyzed. The results show that the preparation process of catalysts and assistants had great effects on catalytic activity; when steeping fluid concentration was 2 mol/L and 0.01 mol/L cerium nitrate was used as an assistant, Fe-Ce/5A catalyst roasted for 3 h at 400 ~C had a good catalytic effect. As 10 g of Fe-Ce/5A catalyst was added to water sample, and landfill leachate pretreated by MBR reacted with 15 ml of H2 02 for 30 min at 60 ~C, the removal rate of ammonia nitrogen was up to 90.8%, that is, ammonia nitrogen concentra- tion decreased from 253 to 23 mg/L, reaching the national emission standard. Besides, the kinetic analysis of ammonia nitrogen removal reveals that the removal reaction of ammonia nitrogen conformed with pseudo first order kinetic equation. Thus, it is feasible to use this method to deeply treat landfill leachate pretreated by MBR.

干湿交替灌溉和施氮量对粳稻光合特性和氮素吸收利用的影响

水分和氮素对水稻叶片光合特性和氮素吸收利用有重要影响,但在干湿交替灌溉条件下,水、氮是如何影响水稻叶片和根系氮代谢酶活性、产量和氮素吸收利用的仍不清楚。探明这一问题对于协同提高产量和氮肥利用效率有重要意义。本研究以超级稻品种南粳9108为材料,大田种植,设置全生育期常规灌溉(conventional irrigation,CI)和干湿交替灌溉(alternate wetting and drying irrigation,AWD)2种灌溉方式及5个施氮水平,不施氮(N0)、施氮90 kg hm^(-2)(N1)、施氮180 kg hm^(-2)(N2)、施氮270 kg hm^(-2)(N3)和施氮360 kg hm^(-2)(N4)。结果表明,与CI相比,AWD增加了水稻主要生育时期叶片的叶绿素a、叶绿素b、总叶绿素和类胡萝卜素含量,提高了叶片净光合速率,并显著增加了叶片中超氧化物歧化酶、过氧化氢酶、硝酸还原酶、谷氨酰胺合成酶和谷氨酸合成酶活性,显著降低了过氧化物酶、内肽酶活性和丙二醛含量,显著提高了根系中氮代谢酶硝酸还原酶、谷氨酰胺合成酶、谷氨酸合成酶和谷氨酸脱氢酶活性;AWD的产量较CI平均增加了10.4%。AWD显著提高了氮素转运量、氮素转运率、氮肥吸收利用率和氮肥偏生产力,产量和氮肥利用率均以AWD+N3处理组合的最高。因此,轻度干湿交替灌溉配合一定的施氮量,可以充分发挥水、肥效应,促进根系和叶片的氮代谢水平,提高叶片光合特性,协调地下地上部生长,有利于水稻产量和氮肥利用率的协同提高。

三种灭菌包装材料在骨科手术器械包中的应用效果探究

目的:探讨三种灭菌包装材料在骨科手术器械包中的应用效果。方法:将广西中医药大学第一附属医院2022年8月—2023年4月骨科手术器械包分别用普通棉布、一次性无纺布和新型纺织品三种包装材料进行包装灭菌,每种包装材料各300包。比较三种灭菌包装材料湿包发生率、总综合成本。结果:新型纺织品湿包率低于普通棉布及一次性无纺布(P<0.05);普通棉布与一次性无纺布湿包率比较,差异无统计学意义(P>0.05)。普通棉布综合成本为(2615.25±5.18)元,一次性无纺布综合成本为(5530.00±10.26)元,新型纺织品综合成本为(2711.68±6.45)元;其中总综合成本最低的为普通棉布,新型纺织品次之。结论:三种灭菌包装材料中使用普通棉布的湿包率最高,但总综合成本最低(过期后再处理未计成本);一次性无纺布易湿包,且总综合成本最高;新型纺织品湿包率最低,总综合成本相对较低,性价比更高。

Influence of Seed Priming on Performance and Water Productivity of Direct Seeded Rice in Alternating Wetting and Drying

Direct seeded rice is promising alternative to traditional transplanting, but requires appropriate crop and water management to maintain yield performance and achieve high water productivity. Present study evaluated the effect of seed priming and irrigation on crop establishment, tillering, agronomic traits, paddy yield, grain quality and water productivity of direct seeded rice in alternate wetting and drying （DSR-AWD） in comparison with direct seeded rice at field capacity （DSR- FC）. Seed priming treatments were osmo-priming with KCI （2.2%）, CaCI2 （2.2%） and moringa leaf extracts （MLE, 3.3%） including hydro-priming as control. Among the treatments, seed osmo-primed with MLE emerged earlier and had higher final emergence, followed by osmo-priming with CaCI2. Tillering emergence rate and number of tillers per plant were the highest for seed priming with CaCI2 in DSR- AWD. Total productive and non-productive tillers, panicle length, biological and grain yields, harvest index were highest for seed priming with MLE or CaCI2 in DSR-AWD. Similarly, grain quality, estimated in terms of normal grains, abortive and chalky grains, was also the highest in DSR-AWD with MLE osmo-priming. Benefit cost ratio and water productivity was also the highest in DSR-AWD for seed priming with MLE. In conclusion, seed priming with MLE or CaCI2 can be successfully employed to improve the direct seeded rice performance when practiced with alternate wetting and drying irrigation.

铁尾矿混凝土力学性质及耐久性

这是一篇陶瓷及复合材料领域的论文。为了研究铁尾矿混凝土在受硫酸钠溶液干湿循环作用后的力学特性和耐久性,开展了受硫酸钠溶液侵蚀混凝土的抗压实验、抗氯离子侵蚀实验、抗冻实验和水化特性实验,分析不同铁尾矿掺量、干湿循环次数、溶液浓度对混凝土力学性质和耐久性的影响。结果表明:在铁尾矿掺量为30%、干湿循环次数为60次和硫酸钠浓度为5%时,混凝土的质量损失率较小而抗压强度耐腐蚀系数较大。随着铁尾矿掺量的不断增大,混凝土的抗氯离子侵蚀性能、抗冻性能越好,水化反应放热量不断减小。

LaFeO_(3)钙钛矿催化剂的制备及其对苯酚的降解处理

采用球磨、溶胶凝胶和共沉淀3种方法制备了LaFeO_(3)钙钛矿催化剂前驱体,通过改变焙烧温度获得了一系列LaFeO_(3)钙钛矿催化剂。利用XRD、FT-IR、N2物理吸脱附、H2-TPR和XPS等手段对催化剂的结构和性质进行了表征,并考察了其催化湿式空气氧化苯酚性能。结果表明,制备方法对催化性能有较大影响。同时低温还原能力强、氧空位多的催化剂催化活性较高。采用溶胶凝胶法,800℃焙烧制备的催化剂的催化活性较好,在反应温度为200℃,空气压力为5 MPa,苯酚初始浓度为4000 mg·L^(-1)的条件下,最终(240 min)的COD去除率为95.4%。

冻融干湿循环条件下粒径及盐分对土壤粗颗粒风化速率的影响

【目的】探究冻融干湿循环条件下,土壤粒径及盐分对土壤粗颗粒风化速率的影响。【方法】以土壤粗颗粒(灰绿板岩)为研究对象,设置粒径(10、20、30mm)、盐分浓度(3、6、10g/L及蒸馏水作对照)两因素,开展冻融干湿循环随机试验,分析不同循环次数下土壤粗颗粒风化速率的变化规律。【结果】(1)在水盐溶液处理下土壤粗颗粒风化速率均比单纯水处理大,10g/L盐分处理下的土壤粗颗粒风化速率大于其他处理。在20~60次冻融干湿循环之间,10 mm土壤粗颗粒的风化速率随盐分浓度的增加而增大。(2)土壤粗颗粒风化速率随粒径的增大呈减小趋势,且10 mm的土壤粗颗粒风化速率大约是30 mm的2倍。(3)土壤粗颗粒风化速率随冻融干湿循环次数的增大而增大,A1B4(10 mm 10 g/L)组合下的土壤粗颗粒风化速率最大。【结论】在冻融干湿循环影响下,小粒径的土壤粗颗粒风化速率大于大粒径,且水盐作用对土壤粗颗粒风化速率的影响大于单纯水作用。

依鲁替尼纳米晶的制备工艺研究

为改善依鲁替尼(IBR)的水溶性和溶出度,采用湿法介质研磨法制备了依鲁替尼纳米晶(IBR-NC),采用单因素实验优化了IBR-NC的制备工艺,并通过粒径分析、扫描电镜(SEM)、X-射线粉末衍射(XRPD)分析、差示扫描量热(DSC)分析及溶出度实验对IBR-NC的质量进行了评价。结果表明,以PVP-K30-SDS为稳定剂,在物料比(IBR、PVP-K30、SDS的质量比)为10∶4∶1、IBR用量为120 mg、氧化锆珠规格为0.3 mm、氧化锆珠用量为40 g、研磨转速为150 r·min^(-1)、研磨时间为2.0 h的最优条件下,制备的IBR-NC的粒径为(224.7±5.7)nm、PDI为0.151±0.017,累积溶出率在10 min能达到99.49%,溶出效果良好,且放置90 d后依然具有良好的溶出性质。

干湿循环下重塑粉质黏土湿陷变形及其影响因素研究

为研究粉质黏土在干湿循环作用下的湿陷变形规律,以银川粉质黏土为研究对象,制备不同饱和度和压实度的试样,进行干湿循环作用下的湿陷变形试验。结合多因素交互作用的显著性分析法,对不同影响因素下湿陷变形率进行分析。结果表明:压实度及饱和度对湿陷变形率产生了不同程度的影响;对于中低饱和、高饱和土体,在干湿循环作用下,压实度对减缓湿陷变形作用显著性不同,且减缓效果与干湿循环过程相关。干湿循环次数、压实度、饱和度的三因素显著性分析结果表明,三因素显著性均为强,交互作用对湿陷变形率显著性程度不同。为减小压实度和饱和度对地基变形的影响,建议初始压实度不低于95%,且不宜超过最优含水率所对应的饱和度。

不同水质对石膏豆腐加工品质影响的研究

本研究旨在探讨不同水质对石膏豆腐加工品质的影响,包括蛋白质溶出率、湿豆腐得率、豆腐的保水性和持水性、质构特性以及感官评分等方面。通过对5种不同水质条件下的豆腐制作进行实验分析,我们发现碱性软水有利于提高蛋白质的溶出率,从而获得更优质的豆腐产品。相比之下,硬度较高的喀斯特地貌水不利于蛋白质的溶出,导致豆腐凝胶网络结构不够紧密,影响豆腐的整体品质。此外,自来水中的氯气、铁质和微生物等也对豆腐的口感和稳定性产生负面影响。研究结果表明,通过合理选择和调控水质,可以有效提高豆腐的加工品质,为大豆加工业提供了重要的技术参考。本研究为传统豆制品的大规模工业化生产提供了技术指导和理论依据,有助于提升豆制品的产量和质量,同时为低品质豆子的综合利用提供了新的思路。

横坡垄作措施下层状棕壤的积水入渗特征及其模拟

横坡垄作系统中雨水/灌溉水易在垄沟低洼处积聚,诱发积水入渗,使入渗特性有别于传统耕作系统。基于横坡垄作垄沟内积水特征,采用室内土柱供水实验,以层状棕壤为研究对象,分析5个积水深度(2、4、6、8和12 cm)下入渗率、湿润锋运移动态变化,并利用修正的Gree n-Ampt模型对积水入渗过程进行模拟。结果表明:1)耕层阶段,入渗率呈急剧下降后趋于稳定趋势;过渡阶段,入渗率稳定一定时段后逐渐降低;犁底层阶段,入渗率趋于稳定;2)积水深度的增加均促进湿润锋的运移,但未改变湿润锋运移过程;3)初始入渗率、稳定入渗率、平均入渗率、累积入渗量等入渗参数均随积水深度增加呈幂函数增大,其中积水深度12、8、6和4 cm下的平均入渗率较积水深度2 cm分别增加120.5%、65.4%、39.4%和29.9%;4)在解析积水深度(h)与饱和导水率(K_(s)(h))间呈线性正相关关系基础上(K_(s)(h)=0.092h+0.76),结合湿润锋处土壤吸力(25.61 cm),构建模拟积水入渗过程的修正Green-Ampt模型。积水深度的增加加快土壤水分入渗,可利用修正Green-Ampt模型对积水入渗过程进行模拟。研究结果可为横坡垄作措施下水分高效利用、水资源调控提供科学依据。

废弃轮胎胶粉改良膨胀土裂隙机理研究

为探究干湿循环作用下废弃轮胎胶粉改良膨胀土裂隙演化机理,根据无侧限抗压强度试验结果从20目(833μm)、60目(246μm)、100目(147μm)粒径中筛选出最优粒径,通过干湿循环试验和扫描电镜研究最优粒径下不同掺量(0、4%、8%、12%、16%)土体裂隙演化机理及微观结构。结果表明,改良土裂隙面积率均低于素土裂隙面积率,且裂隙面积率随干湿循环次数的递增呈先增后趋于平稳趋势,第5次干湿循环后,改良土裂隙面积率较素土依次降低40.03%、46.78%、56.75%、66.55%;同一干湿循环次数下,裂隙面积率随掺量增加而降低;裂隙面积愈合率随掺量增加而增大,粒径为20目且掺量为4%、8%、12%、16%的胶粉改良土较素土分别提升10.56%、14.57%、19.42%、44.85%。这是因为加入胶粉将松散单元汇聚一团,填充了土体孔隙,使得微观结构更致密,提高了土体持水性,使得土体结构更稳定,对土体的裂隙发育起到较好的抑制作用。

基于降雨—库水作用下的某库岸堆积体滑带土力学性能及损伤模型研究

库水及降雨往复作用下滑带土的力学性能演化是库岸滑坡形成发展及破坏的内在控制因素。基于宏微观室内试验和理论分析手段,研究了干湿循环作用下滑带土性能的劣化机理及力学损伤特性,并建立了基于宏观强度的微观损伤演化模型。结果表明,随干湿循环次数的增加,滑带土内摩擦角和粘聚力均出现降低趋势,剪切强度劣化率随干湿循环扰动程度的增加而显著提高;亲水矿物及干湿循环下的水动力影响效应,使得土样微观结构由致密向疏松多孔转变,颗粒间微裂纹及原生孔隙迅速增加。基于损伤力学和室内试验提出的宏微观损伤模型可有效表征干湿循环作用下滑带土的劣化规律。

新型旋流布液器成膜性能实验研究

布液器是降膜蒸发器的关键部件。文章针对现有布液器存在的不足,开发了一种新型旋流布液器。该布液器为切向开槽结构,槽一侧与管内壁相切,另一侧延伸一定长度与管内壁形成导流结构,下端与换热管通过螺纹连接。在有机玻璃实验装置内对新型旋流布液器和切向槽型布液器形成液膜等性能进行了系统的对比研究。实验结果表明:只要合理控制流量,两种布液器均能连续稳定成膜,不会出现“干管”现象;新型旋流布液器的最小成膜流量更小,成膜的流量范围更广,说明其操作弹性更大;在相同流量下,新型旋流布液器比切向槽型布液器形成的液膜厚且流速小,因此液膜稳定性更好,同时液膜在换热管内的停留时间更长,换热效果更好。

半导体碳化硅衬底的湿法氧化

半导体碳化硅(4H-SiC)材料具有硬度高、脆性大、化学性质稳定等特点,一般使用化学机械抛光工艺来加工4H-SiC以获得超光滑平坦表面。湿法氧化作为单晶4H-SiC化学机械抛光的重要过程,直接影响着化学机械抛光的速率和表面质量。本文综述了目前单晶4H-SiC湿法氧化的研究现状,讨论了4H-SiC湿法氧化工艺所选用的氧化剂,如KMnO_(4)、H_(2)O_(2)、K_(2)S_(2)O_(8)等。在此基础上,进一步总结了常用的氧化增效方法,如光催化辅助氧化、电化学氧化、芬顿反应等,并从理论计算的角度分析了单晶4H-SiC湿法氧化的机理,最后展望了4H-SiC湿法氧化未来的研究方向。

干湿循环下煤矸石混凝土氯离子分布规律研究

为研究在干湿循环下煤矸石混凝土中氯离子的分布规律,利用质量分数为3.5%的NaCl溶液对煤矸石混凝土进行干湿循环试验,探究了煤矸石替代率(0、25%、50%)、连续干湿循环和非连续干湿循环、干湿比(23∶1、22∶2、20∶4)对混凝土中氯离子浓度与对流区深度等的影响。结果表明,随着混凝土深度增加,氯离子浓度先在距表面0~4 mm上升,随后在4~15 mm急剧下降,之后趋于平稳。随着煤矸石替代率的增加,氯离子浓度整体呈上升趋势,对流区深度随之减小,替代率50%的混凝土对流区深度最小,约为2 mm。煤矸石混凝土的侵蚀深度大于未掺组。干湿比的增大和非连续干湿循环均会导致氯离子峰值浓度和氯离子浓度减小,干湿比为23∶1时,对应的氯离子峰值浓度最大。对流区深度与干湿比的变化无关。