Lignin,lignosulfonate,and synthesized phosphorylated lignosulfonate were introduced as greenfillers in citric acid-sucrose adhesives for bonding particleboard fabricated from areca leaf sheath(ALS).The characteristics ...Lignin,lignosulfonate,and synthesized phosphorylated lignosulfonate were introduced as greenfillers in citric acid-sucrose adhesives for bonding particleboard fabricated from areca leaf sheath(ALS).The characteristics of particleboards were compared to that of ultralow emitting formaldehyde(ULEF-UF).Thefillers derived from Eucalyptus spp.kraft-lignin were added forflame retardancy enhancement.10%of each lignin and modified lig-nin was added into the ULEF-UF and citric acid-sucrose bonded particleboards.Analyses applied to particle-boards included thermal characteristics,X-ray diffraction analysis(XRD),morphological properties,Fourier transform infrared spectroscopy(FTIR),as well as physical,mechanical,andfire resistance characteristics of the laboratory-fabricated particleboards.Lignin and modified lignin resulted in improved thermal stability of the composites bonded with ULEF-UF while the improvement in the particleboard bonded with citric acid-sucrose was not significant.The introduction offiller exerted a higher influence on the UF-bonded particleboards compared to composites fabricated with citric acid-sucrose.Generally,the presence of lignin,lignosulfonate,and phosphorylated lignosulfonate enhanced the mechanical strength of the ULEF-bonded particleboards,although their dimensional stability has deteriorated.Markedly,the use of lignin and lignosulfonate enhanced thefire resis-tance of the particleboards produced with lower observed weight loss.All laboratory particleboards exhibited satisfactoryfire resistance,attaining a V-0 rating in according to the UL-94 standard.展开更多
为了解决车辆行驶中面对各种复杂环境车道线检测算法精度不高的问题,提出一种基于改进的UFS网络检测算法(Ultra Fast Structure-aware Deep Lane Detection,UFS).首先,采用改进的Gamma校正对待检路面图像进行校正,降低光照、阴影等的影...为了解决车辆行驶中面对各种复杂环境车道线检测算法精度不高的问题,提出一种基于改进的UFS网络检测算法(Ultra Fast Structure-aware Deep Lane Detection,UFS).首先,采用改进的Gamma校正对待检路面图像进行校正,降低光照、阴影等的影响,以提升夜间图像纹理特征。然后引入非局部神经网络模块(Non-Local Block),充分提取图像全局特征,以提高检测可靠性。最后对改进后的算法使用Tusimple、CULane数据集进行测试。结果表明:改进后的模型在物体遮挡、光照变化、阴影干扰等复杂场景下,提升了对复杂噪声与多元场景的处理能力,车道分割的准确率有所改善,具有较好的鲁棒性。展开更多
A new composite two component grout comprised of modified urea-formaldehyde resin and cement was formulated to take account of the advantages and disadvantages of both the cement grout and the chem- ical grout. The ne...A new composite two component grout comprised of modified urea-formaldehyde resin and cement was formulated to take account of the advantages and disadvantages of both the cement grout and the chem- ical grout. The new grout is designed for water blocking by reinforcing as well as seepage control by bore grouting. The A component consists of a modified urea-formaldehyde resin A component, some cement, and some water. The B component is an alkaline coagulant. An orthogonal test of four factors at three lev- els showed that gel time increased with increased water content and with urea-formaldehyde resin con- tent. Gel time decreased at increased levels of alkaline coagulant. The A component of this new composite grout is stable over time. A mixed cross-over test showed that as the volume ratio of A to B increases the gel time falls at first but then increases. The solid strength decreases with increasing levels of the B com- ponent. The solid strength increases over time and becomes stable by the 28th day after mixing. The vis- cosity increases with increasing levels of resin A component. The increase is exponential and may be fit to： μ = 8.162e0.0286x.展开更多
Urea-formaldehyde (UF) resin is widely used as an adhesive for the manufacture of a range of wood and fiber based products. Although the microstructure of this resin has been examined at high resolution by field-emiss...Urea-formaldehyde (UF) resin is widely used as an adhesive for the manufacture of a range of wood and fiber based products. Although the microstructure of this resin has been examined at high resolution by field-emission scanning electron microscopy and atomic force microscopy, transmission electron microscopy (TEM) has thus far not been used, perhaps because of difficulties in ultrathin sectioning this resin in cured (polymerized) state. In the technical note presented here, a novel sample preparation method is described which enabled us to examine the microstructural morphology of UF resin by transmission electron microscopy in ultrathin sections, revealing the presence of spherical particles within the resin. Our initial attempt to ultrathin section the resin directly was not successful as it was too brittle to trim blocks for sectioning. Then, we developed a sample preparation technique that involved impregnation ofPinus radiatawood tissues with the UF resin, and then embedding of resin impregnated wood tissues with Spurr’s low viscosity embedding medium, which has been widely employed in plant and wood ultrastructure work. The TEM images illustrated and the information on the microstructural morphology of the UF resin presented are based on this novel sample preparation approach.展开更多
Spherical macroporous adsorbents with active sites capable of hydrogen bonding adsorption based on urea-formaldehyde condensed polymer were synthesized via reversed suspension polymerization. The properties of the obt...Spherical macroporous adsorbents with active sites capable of hydrogen bonding adsorption based on urea-formaldehyde condensed polymer were synthesized via reversed suspension polymerization. The properties of the obtained adsorbent were also investigated in detail. The results showed that the water permeability could be improved by adding hydroxyl-containing organic compound moiety into the adsorbent. The specific surface area and average pore diameter of these adsorbents increased while the porosity first increased then decreased with the increase of the amount of the added hydroxyl-containing compound.展开更多
The selective water plugging agent was prepared by heating the blends of the polyacry-lamide inverse latex, modified urea formaldehyde resin, crosslinking agent and catalysts.The results show that using different type...The selective water plugging agent was prepared by heating the blends of the polyacry-lamide inverse latex, modified urea formaldehyde resin, crosslinking agent and catalysts.The results show that using different types of polymers and additives or changing in theirproportion of the blends, the gelling viscosity, starting point of gelling and other propertiesof the IPN can be controlled.展开更多
基金funded by the Equity Project Universitas Sumatera Utara(Number:10/UN5.2.3.1/PPM/KPEP/2023),which is entitled Pengembangan Papan Partikel Tahan Api Rendah Emisi Berbahan Limbah Tanaman Mangrove dan Limbah Tanaman Pertanian Melalui Penambahan Lignin Terfosforilasi Sebagai Filler.PT Greenei Alam Indonesia(PT GAI)contributed to providing the areca leaf sheath through the implementation of a collaboration agreement with the Research Center for Biomass and Bioproducts BRIN FY 2023-2025.
文摘Lignin,lignosulfonate,and synthesized phosphorylated lignosulfonate were introduced as greenfillers in citric acid-sucrose adhesives for bonding particleboard fabricated from areca leaf sheath(ALS).The characteristics of particleboards were compared to that of ultralow emitting formaldehyde(ULEF-UF).Thefillers derived from Eucalyptus spp.kraft-lignin were added forflame retardancy enhancement.10%of each lignin and modified lig-nin was added into the ULEF-UF and citric acid-sucrose bonded particleboards.Analyses applied to particle-boards included thermal characteristics,X-ray diffraction analysis(XRD),morphological properties,Fourier transform infrared spectroscopy(FTIR),as well as physical,mechanical,andfire resistance characteristics of the laboratory-fabricated particleboards.Lignin and modified lignin resulted in improved thermal stability of the composites bonded with ULEF-UF while the improvement in the particleboard bonded with citric acid-sucrose was not significant.The introduction offiller exerted a higher influence on the UF-bonded particleboards compared to composites fabricated with citric acid-sucrose.Generally,the presence of lignin,lignosulfonate,and phosphorylated lignosulfonate enhanced the mechanical strength of the ULEF-bonded particleboards,although their dimensional stability has deteriorated.Markedly,the use of lignin and lignosulfonate enhanced thefire resis-tance of the particleboards produced with lower observed weight loss.All laboratory particleboards exhibited satisfactoryfire resistance,attaining a V-0 rating in according to the UL-94 standard.
文摘为了解决车辆行驶中面对各种复杂环境车道线检测算法精度不高的问题,提出一种基于改进的UFS网络检测算法(Ultra Fast Structure-aware Deep Lane Detection,UFS).首先,采用改进的Gamma校正对待检路面图像进行校正,降低光照、阴影等的影响,以提升夜间图像纹理特征。然后引入非局部神经网络模块(Non-Local Block),充分提取图像全局特征,以提高检测可靠性。最后对改进后的算法使用Tusimple、CULane数据集进行测试。结果表明:改进后的模型在物体遮挡、光照变化、阴影干扰等复杂场景下,提升了对复杂噪声与多元场景的处理能力,车道分割的准确率有所改善,具有较好的鲁棒性。
基金the Graduate Developing Innovation Project of Jiangsu Province of China (No. CXZZ11-0306)the Major State Basic Research and Development Program of China (No.2007CB209400)
文摘A new composite two component grout comprised of modified urea-formaldehyde resin and cement was formulated to take account of the advantages and disadvantages of both the cement grout and the chem- ical grout. The new grout is designed for water blocking by reinforcing as well as seepage control by bore grouting. The A component consists of a modified urea-formaldehyde resin A component, some cement, and some water. The B component is an alkaline coagulant. An orthogonal test of four factors at three lev- els showed that gel time increased with increased water content and with urea-formaldehyde resin con- tent. Gel time decreased at increased levels of alkaline coagulant. The A component of this new composite grout is stable over time. A mixed cross-over test showed that as the volume ratio of A to B increases the gel time falls at first but then increases. The solid strength decreases with increasing levels of the B com- ponent. The solid strength increases over time and becomes stable by the 28th day after mixing. The vis- cosity increases with increasing levels of resin A component. The increase is exponential and may be fit to： μ = 8.162e0.0286x.
文摘Urea-formaldehyde (UF) resin is widely used as an adhesive for the manufacture of a range of wood and fiber based products. Although the microstructure of this resin has been examined at high resolution by field-emission scanning electron microscopy and atomic force microscopy, transmission electron microscopy (TEM) has thus far not been used, perhaps because of difficulties in ultrathin sectioning this resin in cured (polymerized) state. In the technical note presented here, a novel sample preparation method is described which enabled us to examine the microstructural morphology of UF resin by transmission electron microscopy in ultrathin sections, revealing the presence of spherical particles within the resin. Our initial attempt to ultrathin section the resin directly was not successful as it was too brittle to trim blocks for sectioning. Then, we developed a sample preparation technique that involved impregnation ofPinus radiatawood tissues with the UF resin, and then embedding of resin impregnated wood tissues with Spurr’s low viscosity embedding medium, which has been widely employed in plant and wood ultrastructure work. The TEM images illustrated and the information on the microstructural morphology of the UF resin presented are based on this novel sample preparation approach.
基金uported by the National Natural Science Foundation of China !(Grant No. 29574164)
文摘Spherical macroporous adsorbents with active sites capable of hydrogen bonding adsorption based on urea-formaldehyde condensed polymer were synthesized via reversed suspension polymerization. The properties of the obtained adsorbent were also investigated in detail. The results showed that the water permeability could be improved by adding hydroxyl-containing organic compound moiety into the adsorbent. The specific surface area and average pore diameter of these adsorbents increased while the porosity first increased then decreased with the increase of the amount of the added hydroxyl-containing compound.
文摘The selective water plugging agent was prepared by heating the blends of the polyacry-lamide inverse latex, modified urea formaldehyde resin, crosslinking agent and catalysts.The results show that using different types of polymers and additives or changing in theirproportion of the blends, the gelling viscosity, starting point of gelling and other propertiesof the IPN can be controlled.
文摘目的:评估UF5000检测尿液中酵母样真菌(yeast-like cells,YLC)结果的准确性,并研究该参数能否用于筛查真菌性尿路感染。方法:选取318例疑似尿路感染患者的尿液标本,分别进行UF5000检测和细菌、真菌培养,显微镜镜检记录尿液中是否存在酵母菌。分别以镜下见到酵母菌和培养出真菌作为金标准,ROC曲线分析进行准确性评估。根据是否培养出真菌,以及真菌菌落生长的数量对尿液标本进行分组,非参数检验用于比较不同组间YLC水平的差异。结果:UF5000检测YLC真阳性的曲线下面积(Area under curve,AUC)为0.863,最佳cut off值2.80/μL。UF5000检测YLC预测真菌性尿路感染的AUC为0.913,最佳cutoff值8.95/μL。均有良好的敏感性(95.45%~97.37%)和阴性预测值(98.62%~98.73%)。组间比较显示真菌组YLC水平明显高于阴性组和细菌组(P值均为0.000),而真菌组内亚组仅≥105CFU/mL组YLC水平与105CFU/mL组差异有统计学意义(P=0.027)。结论:选取2.8/μL作为YLC的阳性标准,比厂家提供的6.0/μL更适用于本实验室的临床工作。选取8.95/μL作为最佳cutoff值时,UF5000检测的YLC结果可有效地筛查真菌性尿路感染。
