Measurement of in situ Phosphorus Availability in Acidified Soils using Iron-Infused Resin

A hybrid anion resin was tested for in situ phosphorus (P) availability measurement in soils of two stands recovering from acidification and having different P-sorption characteristics. The phosphate (P-PO₄) sorption capacity of the resin (before saturation) was 48 µmol g^?1. Sorption and elution were tested under P-PO₄ concentrations common in acidic soils (0–0.42 mmol l^?1) either with or without the presence of sulfate (0.2 mmol l^?1). The efficiency of P-PO₄ sorption was independent of the sulfate and was 100 ± 0.2% (n = 56, ± SD). The P-PO₄ recovery stabilized after six elution steps (each: 50 ml of 0.5 M sodium hydroxide, resin/solution 5:1). The efficiency of P-PO₄ recovery was 80 ± 7% and was used to evaluate field measurements. We determined the amount of P-PO₄ in the field using resin bags in three consecutive years. The results indicate that bioavailable P is negatively related to the soil ability to retain P.     

高支化聚脲对脲醛树脂胶黏剂耐水性能和甲醛释放量的影响

引入高分子量、高支化度以及端基为尿素的高支化聚脲(HBPU)用于低摩尔比脲醛树脂(UF)改性,利用HBPU与游离甲醛的反应以及与UF组分的共缩聚反应实现树脂耐水性能的提升和人造板甲醛释放量的降低,有效平衡胶合性能和甲醛释放量之间的矛盾。在无溶剂、无催化剂条件下,通过尿素(U)与三(2-氨基乙基)胺(TAEA)的脱氨缩合反应,一步合成了具有尿素端基的HBPU,并对HBPU的分子量分布和结构进行了表征。使用HBPU水溶液,采用UF合成反应后期加入和共混2种方法对UF进行改性,通过胶合板性能测试以及甲醛释放量测定,考察了HBPU添加量和添加方式的影响。凝胶渗透色谱和碳-13核磁共振分析表明,通过本研究的合成方法可以获得具有高分子量、高支化度、尿素为端基且水溶性良好的HBPU,并且随着U与TAEA摩尔比的提高,更多尿素封端产物形成。电喷雾电离质谱对改性树脂的分析结果表明,HBPU不仅与UF中的一部分游离甲醛发生羟甲基化反应,同时与UF组分反应生成了部分共缩聚产物。胶合板性能测试结果表明,共混以及反应后期加入HBPU两种方式得到的改性树脂耐水性能均显著提升。同时,使用添加5%HBPU改性树脂制备...     

Water reuse in closed hydroponic systems: Comparison of GAC adsorption,ion exchange and ozonation processes to treat recycled nutrient solution

In this study, the removal of root exudates from recycled nutrient solution (RNS) in hydroponic systems was investigated by using alternative advanced treatment processes. In particular, the performance of adsorption on granular activated carbon (GAC adsorption), ion exchange (using Amberlite IRA96) and ozonation was evaluated. The characterization of a RNS from a lettuce hydroponic company showed the occurrence of several organic acids including benzoic, maleic, palmitic, stearic, phthalic, succinic, acrylic, adipic, myristic, mannonic, oleic, arachidic and acetic acid. Furthermore, benzoic, acrylic, myristic and palmitic acid were detected even after the RNS treatment by GAC adsorption, ion exchange or ozonation. Further experiments were performed to evaluate the removal efficiency of root exudates from RNS by the selected treatment processes. For this purpose benzoic acid (BA), which is a potent growth inhibitor, was selected as target compound. Benzoic acid occurring at 23 μg/L in the RNS was completely removed by GAC adsorption, ion exchange or ozonation process. In addition, GAC adsorption was the most efficient technique for organic matter removal. Indeed, the COD removal efficiency was 74%, 67% and 22% for GAC adsorption, ozonation and ion exchange treatments, respectively. The results from UV–vis absorbance measurements corroborated the best performance of activated carbon in organic compounds removal from RNS. For instance, the absorbance removal at 280 nm reached 82%, 51% and 27% after GAC adsorption, ozonation and ion exchange treatments, respectively.     

Improvement of dimensional stability and weatherability of composite board made from water-vapor-exploded wood elements by liquefied wood resin impregnation

High-density and high-resin-content boards were produced by phenolic resin impregnation into board materials prepared by the water-vapor-explosion process (WVE) to develop high-durability wood composite boards for exterior use. Wet-dry cyclic tests and accelerated weathering tests were conducted, and the fundamental properties were determined to examine the effect of resin impregnation on board qualities. Bending and internal bond strength of resin-impregnated boards (I-board) satisfied the criterion for 18-type particleboard described in JIS A 5908. Thickness swelling (TS) after 24-h water immersion was approximately 2%. Resin impregnation improved the dimensional stability of the boards. In wet—dry cyclic testing, TS of I-board was the same as that of plywood. The retention ratio of modulus of rupture of I-board was large; thus, I-board had high bond durability. Color change of I-board was less than that of ordinary particleboard after a 500-h accelerated weathering test. I-Board had lower surface roughness than boards produced by a spray application method (S-board) and higher water repellency, although the difference in resin contents of the face layer was small. Thus, it is suggested that the surface properties and weatherability of I-board were improved by impregnation of phenolic resin. High-density and resin-impregnated boards made from the WVE elements are expected to withstand actual exterior use. Part of this report was presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, August 2004     

苹果汁中溴氰菊酯残留的大孔树脂吸附分

为去除苹果汁中残留的溴氰菊酯,利用大孔吸附树脂对苹果汁中溴氰菊酯的吸附性能及参数进行了研究.通过树脂吸附溴氰菊酯的静态吸附试验, 对大孔吸附树脂进行了筛选,同时,在动态吸附试验的基础上,对最佳吸附动态条件进行了优化,结果表明:LS-803型树脂对溴氰菊酯的吸附能力最强, 其静态吸附时间为100 min;通过正交试验确定了LS-803型树脂较佳的动态吸附条件为: 温度20℃、苹果汁质量浓度110 g/L、流速4 mL/min.     

味连须肠溶微丸包衣处方的筛选

以挤出滚圆法制备味连须微丸为载药丸芯,以丙烯酸树脂Ⅱ和Ⅲ为包衣材料,利用多功能造粒包衣机对丸芯进行包衣。以味连须微丸体外释放度为指标,通过单因素试验考察丙烯酸树脂Ⅱ和Ⅲ的比例、增塑剂用量、抗静电剂用量和包衣增重,探讨不同包衣处方对药物释放度的影响。结果表明,Ⅱ、Ⅲ号丙烯酸树脂比例为2∶1,增塑剂用量为聚合物用量的20%,滑石粉为聚合物用量的0.3%,包衣增重10%为优化处方。     

3D打印光敏树脂假喙治疗鹦鹉断喙

对3例上喙不同程度缺损导致采食困难的鹦鹉进行治疗,通过整体方案的制定,采用对标本3D扫描、实际断端测量和软陶翻模的方法采集数据,再经Geomagic Design X修整和编辑后,获得鹦鹉上喙建模数据,进行3D打印光敏树脂假喙。3例病例均采用对接法拼接进行手术安装,术后1周内均恢复采食饮水行为,无副作用,假喙牢固。对接法安装的3D打印的鹦鹉假喙,为鹦鹉断喙病例提供了一种新型、有效的治疗方案。     

Review on Resin-treated Wood

Adding low molecular weight resins into wood can overcome wood intrinsic defects, which is a new approach for the high efficient utilization of plantation. This paper reviews the researches on low molecular weight resins modifying wood, including different impregnating resins, impregnation technologies, properties of treated wood and mechanism of modifying wood. In the end, some suggestions and prospects are put forward.     

新型浸渍酚醛树脂的研制

本文介绍了一种新型浸渍酚醛树脂，通过调整合成工艺及更换添加剂等措施，使该树脂具有良好的水溶性及低量的了酚，用该树脂浸渍的胶膜纸生产的浸渍纸贴面混凝土板板，其耐磨、耐酸碱，耐干裂，耐水蒸气等各项指标都能满足使用要求。