The effect of magnetic field on the impurity binding energy of shallow donor impurities in a Ga1?xInxNyAs1?y/GaAs quantum well

Using a variational approach, we have investigated the effects of the magnetic field, the impurity position, and the nitrogen and indium concentrations on impurity binding energy in a Ga_1−xIn_xN_yAs_1−y/GaAs quantum well. Our calculations have revealed the dependence of impurity binding on the applied magnetic field, the impurity position, and the nitrogen and indium concentrations.     

Diversity and functional characteristics of lactic acid bacteria from traditional kefir grains

Traditional kefir grains were collected from distinct parts of Turkey, and their microbial profile was determined. A wide bacterial biota was observed formed by distinct lactic acid bacteria (LAB) in which Lactococcus lactis strains appeared to be dominant. Yeast species were also identified in kefir grains. Significant levels of antifungal and antibacterial activities were monitored in kefir isolates. All tested LAB produced an exopolysaccharide (EPS) containing glucose and galactose, and some strains formed a fructan‐type EPS. Importantly, low levels of antibiotic resistance were observed among the kefir isolates.     

米曲霉菌今野菌株所产蛋白酶性质的研究

采用(m)2SO4盐析,再透析提纯得到今野菌株的蛋白酶,该酶热稳定性好,40℃保温5小时,剩余酶活为54%,采用正交试验,得其在反应过程中所受因素影响大小为pH＞酶液浓度＞底物浓度＞温度.酶反应的最适pH为7.0,最适温度为40℃.在以酪素为底物时,该蛋白酶的Km值为6.6‰,NaCl对其有抑制作用.抑制类型为非竞争性抑制.     

不同栓塞剂治疗肝巨大海绵状血管瘤的疗效

【摘要】 目的 探讨不同栓塞剂治疗肝巨大海绵状血管瘤中的疗效。方法 2008—2010年经诊断明确的肝海绵状血管瘤30例,行介入栓塞治疗,根据栓塞剂不同分为两组,即平阳霉素碘油乳剂（PLE）联合海藻酸钠微球（KMG）组（A组,15例）及（PLE）组（B组,15例）,术后1、3、6、12 个月进行CT 检查以评价疗效。结果 两组术后成功率均达100%,A、B两组所用PLE剂量分别为（10.9 ± 5.2）ml、（11.4 ± 4.9）ml,两者差异无统计学意义（P > 0.05）,术后第1、3、6个月复查CT,A组瘤体缩小率在50%以上者为分别为9、11、14例,B组分别为0、3、5例（P < 0.05）。术后1周A组患者疼痛较B组明显,差异有统计学意义（P < 0.05）,术后两组部分患者有轻度肝功能异常,主要表现在转氨酶升高,对症处理后恢复正常,经问卷随访A组满意度较B组高。结论 经肝动脉注入PLE治疗肝巨大血管瘤安全、有效, PLE联合KMG组瘤体缩小主要集中在术后第1、3个月内,见效快,但疼痛较PLE组明显。     

Cephalaria syriaca seed oil

Cephalaria syriaca shrad., in Turkish pelemir, grows predominantly in the southeastern district of Turkey as a weed in cereal fields. Pelemir seeds are sometimes used for extraction of their oil, as an improver of baking value of wheat, and as an antistaling agent for bread. The seeds contain 7.8% moisture; their chemical composition on a dry basis is: crude fat, 25.3%, crude protein, 15.9%; N-free extract, 40.4%; crude fiber, 11.9%; crude ash, 6.5%. Characteristics of the seed oil are: specific gravity at 25 C, 0.9229; refractive index at 25 C, 1.4706; saponification value, 192; iodine value, 88.4; thiocyanogen value, 58.8; Reichert-Meissl value, 0.36; Polenske value, 0.25; unsaponifiable matter, 1.24%; hydroxyl value, 20.9. The fatty acid components are: lauric acid, 1.5%; myristic acid, 19.5%; palmitic acid, 9.4%; stearic acid, 2%; oleic acid, 23.0%; linoleic acid, 36.9%. The chemical composition of extracted cakes on a dry basis is: crude protein, 20.4%; crude fat, 0.8%; N-free extract, 50.5%; crude ash, 6.4%; crude fiber; 14.4%%; saponin, 7.5%. The oil contains 7.8% epoxy acid, calculated as epoxy oleic acid, which makes its use as an edible oil rather difficult but renders it usable in industries using epoxidized oils. Due to its high content of myristic acid, the oil is very suitable for soapmaking as well.     

头颈部CT血管造影和ABCD2评分对短暂性脑缺血血管特征及介入疗效评价

【摘要】 目的 探讨头颈部CT血管造影（CTA）及ABCD2评分对短暂性脑缺血发作（TIA）患者血管特征及介入治疗的意义。方法 对2010年1月—2012年1月收治的64例临床诊断TIA患者行ABCD2评分及头颈部CTA检查,分析患者头颈部血管狭窄程度、分布及其与ABCD2评分的相关性。按动脉狭窄程度将患者分为低和中高危组,中高危组中有22例患者行血管支架成形术治疗,分别于术后3、6和12个月进行随访。结果 64例患者中,头颈动脉狭窄52例（81.25％）,累及动脉149段,其中颅内动脉81段（54.36%）,颅外动脉68段（45.64％）。低危组患者动脉狭窄以轻、中度为主,中高危组患者以中、重度为主（χ2 = 10.126,P = 0.018）。与血管支架成形术前的 ABCD2评分（6.41 ± 0.50）分相比,术后患者3、6和12个月评分明显降低,分别为（2.88 ± 0.69）、（2.82 ± 0.63）和（3.00 ± 0.71）分,差异有统计学意义（F = 86.657,P ＜ 0.05）。结论 头颈部CTA联合ABCD2评分能对 TIA患者狭窄血管及介入疗效进行有效评价。     

Synthesis and characterization of copolymers of bromoacrylated methyl oleate

In this study, methyl oleate was bromoacrylated in the presence of N‐bromosuccinimide and acrylic acid in one step. Homopolymers and copolymers of bromoacrylated methyl oleate (BAMO) were synthesized by free radical bulk polymerization and photopolymerization techniques. Azobisisobutyronitrile (AIBN) and 2,2‐dimethoxy‐2‐phenyl‐acetophenone were used as initiators. The new monomer BAMO was characterized by FTIR, GC‐MS, ¹H, and ¹³C‐NMR spectroscopy. Styrene (STY), methylmethacrylate (MMA), and vinyl acetate (VA) were used for copolymerization. The polymers synthesized were characterized by FTIR, ¹H‐NMR, ¹³C‐NMR, and differential scanning calorimetry (DSC). Molecular weight and polydispersities of the copolymers were determined by GPC analysis. Ten different feed ratios of the monomers STY and BAMO were used for the calculation of reactivity ratios. The reactivity ratios were determined by the Fineman–Ross and Kelen–Tudos methods using ¹H‐NMR spectroscopic data. The reactivity ratios were found to be r_sty = 0.891 (Fineman–Ross method), 0.859 (Kelen–Tudos method); r_bamo = 0.671 (Fineman–Ross method), 0.524 (Kelen–Tudos method). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2475–2488, 2004     

Investigation of the performance of carbide cutting tools with hard coatings in hard milling based on the response surface methodology

Machining of hard materials has become a great challenge for several decades. One of the problems in this machining process is early tool wear, and this affects the machinability of hard materials. In order to increase machinability, cutting tools are widely coated with nanostructured physical vapor deposition hard coatings. The main characteristics of such advanced hard coatings are high microhardness and toughness as well as good adhesion to the substrate. In this paper, the influence of hard coatings (nanolayer AlTiN/TiN, multilayer nanocomposite TiAlSiN/TiSiN/TiAlN, and commercially available TiN/TiAlN) and cutting parameters (cutting speed, feed rate, and depth of cut) on cutting forces and surface roughness were investigated during face milling of AISI O2 cold work tool steel (～61 HRC). The experiments were conducted based on 3¹³ factorial design by response surface methodology, and response surface equations of cutting forces and surface roughness were obtained. In addition, the cutting forces obtained with the coated and uncoated tools were compared. The results showed that the interaction of coating type and depth of cut affects surface roughness. The hard coating type has no significant effect on cutting forces, while the cutting force F _z is approximately two times higher in the case of uncoated tool.     

磁梯度法探测钻孔桩钢筋笼长度的应用

建设工程基础桩的施工中,若少放钢筋笼将会造成工程桩的质量隐患,采用地球物理磁梯度法可以有效地检测桩中钢筋笼的节数和长度,并能取得满意的效果.