低强度超声波强化低温SMBR脱氮的性能与机制研究

考察了低温条件下低强度超声波对SMBR脱氮的强化作用,并研究了对硝化细菌脱氢酶活性和细胞通透性的影响。结果表明,经超声波强化后,SMBR对NH3-N5的去除效果得到明显提高,总去除率由启动完成时的65.94%升至84.01%,且长期运行稳定,说明超声波解除了低温对硝化作用的抑制。0.28 W/L超声波辐照20 min,可使硝化细菌脱氢酶活性提高81.19%,0.14 W/L的超声波辐照10 min使脱氢酶活性提高43.18%。0.28 W/L的超声功率密度对脱氢酶的活性提高程度最大,因此是较合适的超声波参数。     

低强度超声波强化SMBR处理中的超声波参数优化研究

研究了利用低强度超声波强化低温一体式膜生物反应器（SMBR）污水生物处理中最优超声波参数的选择。结果表明,功率密度为0.27 W/L、辐照时间为20 min时,超声波对低温SMBR中COD去除的强化效果最佳。SMBR对NH3-N去除效果达到最佳时,超声波功率密度和辐照时间分别为0.27 W/L和15 min。综合考虑,选择更有利于低温时NH3-N去除的超声波参数：功率密度0.27 W/L、辐照时间15 min。经此超声波处理后COD、NH3-N的强化效果在24 h均能保持,故可设置超声波处理的时间间隔为24 h。     

含油污泥超声处理脱油研究

采用槽式超声清洗器辐照含油污泥,辅以气浮浮选,以脱除污油.用w(油)为0.130g/g的含油污泥,对比经28 kHz超声底部向上辐照和未经超声辐照的含油污泥气浮脱油效果.结果表明:在40 ℃水浴下,28 kHz超声辐照脱油后,污泥w(油)达到最小,为0.055 g/g,比未经超声辐照对照组的w(油)(为0.124 g/g)下降约55.6%;28 kHz超声底部辐照方式脱油效果优于40 kHz超声侧面辐照;当28和40 kHz超声辐照的声压辐值分别为0.085和0.120 MPa时,脱油后污泥w(油)最小;添加硅酸钠则降低含油污泥的超声脱油效果.      

Three- versus two-dimensional ultrasound for nuchal translucency thickness measurements: comparison of feasibility and levels of agreement

We have determined feasibility and levels of agreement for visualizing the nuchal translucency within a time limit with three-dimensional (3D) and two-dimensional (2D) transvaginal ultrasound. A total of 213 women of median gestational age 13 weeks (range 11–14 weeks) undergoing first-trimester nuchal translucency (NT) thickness measurements with 2D transabdominal ultrasound were included in the study. Additionally all women underwent 2D and 3D transvaginal NT examination within a time limit of 90 s. These two methods were compared with each other and with our standard method (2D transabdominal ultrasound) with respect to visualization of fetal nuchal fold and to the levels of agreement. The nuchal fold was visualized by 3D and 2D transvaginal ultrasound in 85.9% (95% CI: 80.5%, 90.3%) and 25.8% (95% CI: 20.1%, 32.2%), respectively (p<0.001). There was a statistically significant underestimation of the NT by 2D transabdominal as compared with 3D transvaginal ultrasound of 0.1 mm (p<0.001), and by 3D transvaginal as compared with 2D transvaginal ultrasound of even 0.1 mm (p<0.001). 3D transvaginal ultrasound of the nuchal fold has increased feasibility to 2D transvaginal ultrasound within a short examination time and with minimal, but significant, measurement differences. Copyright © 2001 John Wiley & Sons, Ltd.     

Application of power ultrasound in leather processing: an eco-friendly approach

The paper analyses and reviews in detail the use of ultrasound as a tool to improve the cleanliness of leather production for each stage of leather processing, showing that ultrasound has the added advantages of improving the process efficiency, reducing the process time and improving the quality of leather produced. The rate of diffusion of chemicals such as dyes through the pores of the leather matrix can be enhanced by the use of power ultrasound. Thus the optimum amount of chemicals required can be employed to improve the % exhaustion of chemicals, thereby minimising the significant amount of unspent chemicals in the effluent and reducing pollution load to a large extent. Dyeing experiments carried out in the presence of ultrasound (150 W and 33 kHz) give an increase of about 40% in dye exhaustion and a decrease in dyeing time by about 55% compared with the process in the absence of ultrasound under stationary conditions. Compared with conventional drumming conditions, ultrasound increases dye exhaustion by about 28% and reduces dyeing time by 25%. Ultrasound can also function as a physical activator and reduce the use of conventional chemicals in some of the processing stages, such as soaking for cleaning the raw skin/hide, liming for loosening hair and degreasing for removing natural fat. Therefore, ultrasound can be employed effectively in leather processing to enjoy multifaceted benefits.     

超滤膜的超声波助清洗研究

考察了不同功率的超声波对超滤膜性能的影响.结果表明:20W功率的超声波对超滤膜截留率的影响不大,大于30W以后,超滤膜的截留率下降明显.在此基础上,对实际工业现场印钞擦版废液污染超滤膜的化学清洗过程中,附以20W低功率超声波,可以发挥其超强振动和超搅拌作用,从而将化学清洗时间从20～30min缩短到5min左右,极大地提高了膜清洗效率.SEM的观察结果显示,在仅采用简单的超声波物理清洗时,膜表面的污染物并不能彻底有效地得以清除.     

Compromise ultrasound dating policy in maternal serum screening for Down syndrome

Routine ultrasound biometry is the method of choice for gestational dating when screening for Down syndrome. However, it is costly and an alternative policy is to restrict ultrasound to women most likely to have menstrual dating errors. This was evaluated by statistical modelling with parameters from 14 274 women screened between January 1997 and July 2001 using free beta-human chorionic gonadotrophin (free β-hCG), α-fetoprotein (AFP) and unconjugated estriol (uE₃). A total of 12 711 (89%) women had both ultrasound and menstrual gestations, but in 4101 (29%) women either the last menstrual period (LMP) was uncertain or a pill-withdrawal period, or there were irregular or abnormal length cycles. The LMP was not entered in the test request form for a further 1404 (9.8%) women. Routine ultrasound dating yielded a predicted detection rate higher than for menstrual dating by 3.9–7.1%, depending on the marker combination and cut-off. The false-positive rate was reduced by 0.2–1.1%. Selectively scanning the 39% with unreliable dates increased detection by 2.6–4.6%, and reduced the false-positive rate by 0.04–0.6%. Some centres only use the ultrasound estimate of gestation when it differs from the menstrual estimate by more than 7 days. Such a rule reduces the gain in detection rate to 2.5–4.6% for routine ultrasound and 1.7–3.1% with the compromise policy; the false-positive rate reductions are 0.06–0.6% and 0.0–0.3%, respectively. We conclude that if routine ultrasound is not financially and practically feasible, the compromise policy yields a clinically important improvement in screening performance compared to menstrual dating. Copyright © 2002 John Wiley & Sons, Ltd.     

Mid-trimester fetal ultrasound: Diagnostic dilemmas

Two cases are reported in which an unusual ultrasound finding preceded diagnostic amniocentesis and led to further work-up. In both cases a decision was made to terminate the pregnancy. One fetus in which a neck mass was detected by ultrasound was shown to be normal on post-mortem examination. The second fetus was aborted because of Rh sensitization and had the abnormality seen by ultrasound. However, this lesion, calcified intrahepatic plaques, had no presumed pathological significance. These cases suggest caution in the interpretation of results obtained with the new technologies used for prenatal diagnosis.     

水中染料酸性嫩黄的超声/H2O2降解动力学研究

采用超声/H2O2降解水中酸性嫩黄染料,探讨了超声波/H2O2降解酸性嫩黄的动力学规律并考察了超声波功率、染料初始浓度、H2O2用量以及初始pH对降解速率的影响。结果表明,超声波对酸性嫩黄的降解以及超声波/H2O2对酸性嫩黄的协同降解均符合一级反应动力学规律,降解速率常数随超声波功率的增大而增大,随染料初始浓度的增大而减小;投加适量的H2O2可提高降解速率,但H2O2用量过高反而会使降解速率减慢;溶液pH<5时,降解速率较快,且pH越小,降解速率越快;pH≥5时,降解速率较慢。     

Prenatal obstruction of the ileum diagnosed by ultrasound

A case of low atresia of the ileum, diagnosed prenatally by real-time ultrasound scanning, is presented. The ultrasound examination showed progressive distension of intestinal loops, with strong peristaltic movements. The stomach was also distended, presenting as a large cystic area in the upper left abdomen. Real-time ultrasound technique is most advantageous in the diagnosis of fetal ileus. Prenatal diagnosis of fetal intestinal obstruction is of great importance, making early and safe treatment of the newborn possible.     

超声激发碘自由基降解水中磺胺嘧啶

以H2O2和KI作为分子碘(I2)的来源,研究超声/H2O2/KI体系对磺胺嘧啶(SD)的降解效果.考察超声/H2O2/KI体系中溶液初始pH值、H2O2和KI添加浓度等因素的影响.采用碘自由基抑制剂甲硫咪唑对体系中的活性物质进行分析.结果表明,超声/H2O2/KI体系显著提高了磺胺嘧啶的降解效果,磺胺嘧啶的去除率随溶液初始pH值(2.6~5.2)的升高而降低; H2O2和KI的添加浓度对磺胺嘧啶的去除率影响较大,磺胺嘧啶的去除率随其初始浓度的增大而降低.碘自由基(I·和I2-·)是超声/H2O2/KI体系降解磺胺嘧啶的主要活性物质.HPLC图谱表明,磺胺嘧啶降解的同时生成4种产物,磺胺为降解产物之一.     

Prenatal diagnosis of lissencephaly

We report two cases of prenatal detection of lissencephaly by high-resolution ultrasound. The first case studied was referred for high-risk obstetrical management and serial antenatal ultrasounds because of a family history of lissencephaly in an unresolved chromosomal abnormality. Diagnosis of a smooth gyral pattern consistent with lissencephaly was made at 32 weeks' gestation. The second case was referred for prenatal ultrasound because of a size versus dates discrepancy. The ultrasound examination showed a smooth gyral pattern at 31.5 weeks. In light of this ultrasound finding, a fetal blood sample was obtained and a chromosomal abnormality reported, confirming the diagnosis. To our knowledge, these cases represent the first report of the sonographic prenatal diagnosis of cerebral agyria or lissencephaly.     

Prenatal diagnosis of congenital epulis by three-dimensional ultrasound and magnetic resonance imaging

Congenital epulis is a benign intraoral tumor that has rarely been diagnosed prenatally. We report a fetus with congenital epulis diagnosed by three-dimensional (3-D) ultrasound and fetal magnetic resonance imaging (MRI) at 35 weeks' gestation. We show an image of congenital epulis using a new ultrasound technique, the 3-D multislice view, which shows images similar to CT or MRI. This is a short case report of congenital epulis diagnosed prenatally by 3-D ultrasound using multislice view and MRI. Copyright © 2006 John Wiley & Sons, Ltd.     

Ultrasound-accelerated enzymatic hydrolysis of solid leather waste

The leather industry is a heavy pollution industry and looking for clean technology. The utilization of enzyme and ultrasound in the industry are potential eco-friendly technologies.Enzymes can degrade the untanned solid leather waste. According to our investigation, ultrasound (40 kHz, 0.64 W/cm²) has little effect on the activity of one alkaline protease from Bacillus licheniformis. It is the first time to use ultrasound to accelerate the enzymatic hydrolysis of the untanned solid leather waste. With the application of ultrasound, the value of k_A for the enzymatic hydrolysis of the untanned solid leather waste increases 18% and K_M is almost unchanged, compared with that obtained without ultrasound. Ultrasound improves the ultimate conversion ratio from 57.6% to 84.1%. The reason is that ultrasound can facilitate the protease through the pores of skin and impair the integrity of collagen. Amino acid analysis indicated that ultrasound can promote the breakdown of helical regions of collagen which are difficult to attack by proteases.In view of environment protection, the use of enzyme and ultrasound in combination is a promising clean technology for the disposal of the untanned solid leather waste.     

超声波辅助浸取分离污泥中的重金属

以实验室合成的含重金属离子的污泥为研究对象,通过实验分析对比了不同pH下超声波对污泥中重金属离子去除率的影响。研究表明,在超声波的辅助作用下,一步酸浸法能使Cu-Fe混合污泥中的Cu和Fe完全分离,Cu和Fe的离子浸出率分别是97.47%和1.81%;超声波辅助两步酸浸法分离Cu-Cr污泥中的Cu和Cr,96.52%的Cu溶解在浸出液中,96.64%的Cr保留在浸出渣中,Cu、Cr可完全分离;在Cr-Fe混合污泥中,超声的辅助作用使两步酸浸后Cr的浸出率达97.05%,浸出渣中则含98.48%的Fe,2种金属得到有效的分离。酸浸过程中加入超声波对重金属的分离回收有明显的强化效果。     

Prenatal diagnosis of trisomy 8 mosaicism in cvs after abnormal ultrasound findings at 12 weeks

We describe a case of trisomy 8 mosaicism in which fetal chromosome analysis was prompted by ultrasound abnormalities, i.e., hygroma colli and dilatation of the renal pelves. Chorionic villus sampling (CVS) was performed, with a false-negative result on direct karyotype analysis, although cultured trophoblasts revealed trisomy 8 mosaicism. Fetal autopsy confirmed the abnormalities found on ultrasound examinations and fetal tissue examination showed different levels of trisomy 8 mosaicism. To our knowledge, this is the first prenatal diagnosis of trisomy 8 made on ultrasound findings.     

A comparative study of prenatal ultrasound findings and post-mortem examination in a tertiary referral centre

This retrospective study compares the findings of prenatal ultrasound, performed in a tertiary fetal medicine centre, with the results of post-mortem examination in pregnancies complicated by suspected fetal abnormality that results in fetal loss. The study was carried out over a year at a teaching hospital, Fetal Medicine Centre and Regional Centre for Perinatal Pathology. Results were directly compared and the level of agreement between the ultrasound and post-mortem findings described. These were classified as having complete agreement; major agreement or major disagreement. The group of cases with major agreement between findings was further divided into those with significant, or minor, additional findings at post-mortem examination. Over the 12-month period, 153 ultrasound cases were identified, of which 47 were also examined by autopsy and were thus suitable for comparison in this study (30.7%). Complete agreement between ultrasound and post-mortem findings was found in 22 cases (46.8%). In 24 cases (51.1%), major agreement between ultrasound and post-mortem findings was seen. Of these, 11 had minor additional findings at post-mortem examination and 13 were found to have significant additional findings at post-mortem (27.7%), adding to the eventual diagnosis. In 12.8% of cases, post-mortem examination provided a definitive diagnosis. Only in one case was there complete discordance in the findings of the ultrasound examination and the autopsy (2.1%). No major disagreement between ultrasound and post-mortem findings was seen in 98% of cases. This study confirms the accuracy of prenatal ultrasound diagnosis in specialist centres, whilst emphasising the continuing importance of post-mortem examination in cases of fetal malformation to refine and, in some cases, define the diagnosis. Copyright © 2004 John Wiley & Sons, Ltd.     

Prenatal diagnosis of Mohr syndrome by ultrasonography

A case of prenatal diagnosis of Mohr syndrome is presented. The ultrasound examination was indicated by the previous birth of an affected brother. The need for genetic counselling is stressed, when polydactyly is observed accidentally at ultrasound examination during pregnancy.     

超声波促进污泥过程减量化的研究进展及展望

随着污泥处理处置问题的日益严峻,基于清洁生产理念的污泥过程减量化技术已成为业界的研究热点。超声波以其"绿色、高效"在污泥过程减量化工艺中引起了广泛关注。探讨了超声波促进污泥过程减量化的机理和主要影响因素,概述了单独利用超声波及超声波与其他技术联用促进污泥过程减量化的研究现状,展望了低强度超声波在污泥过程减量化中的应用前景和研究方向。     

超声对净水沉淀污泥絮体特性及对污泥回流效能的影响

为解决污泥回流强化混凝技术存在的有毒有害物质积累的问题,取净水沉淀污泥经超声预处理后进行回流试验,考察超声作用后净水沉淀污泥絮体特性的变化及其对回流效能的影响.结果表明:超声作用后污泥溶液的温度升高,絮体粒径减小,长时间作用后粒径可降至几个mm,且粒径与声能密度呈现相关性;1,5W/mL的超声处理后,絮体Zeta电位降低,比表面积增大,10,15W/mL的超声处理后絮体Zeta电位升高,比表面积有所下降;低声能密度(1W/mL)超声处理后污泥回流可强化混凝效果,30min超声作用后污泥回流的浊度、UV254和CODMn去除率分别提高了2.7%、23.12%和10.02%,长时间高声能密度(15W/mL)超声波处理污泥回流后混凝效果反而恶化.超声技术对污泥回流后污染物的去除率有一定的提高,但超声时间和声能密度必须很好控制.