A Review of Flow Characterization of Metallic Materials in the Cold Forming Temperature Range and Its Major Issues

We focus on the importance of accurately describing the flow behaviors of metallic materials to be cold formed; we refer to several valuable examples. We review the typical experimental methods by which flow curves are obtained, in addition to several combined experimental-numerical methods. The characteristics of four fundamental flow models including the Ludwik, Voce, Hollomon, and Swift models are explored in detail. We classify all flow models in the literature into three groups, including the Ludwik and Voce families, and blends thereof. We review the experimental and numerical methods used to optimize the flow curves. Representative flow models are compared via tensile testing, with a focus on the necking point and pre- or post-necking strain hardening. Several closed-form function models employed for the non-isothermal analyses of cold metal forming are also examined. The traditional bilinear C-m model and derivatives thereof are used to describe the complicated flow behaviors of metallic materials at cold forming temperatures, particularly in terms of their applications to metal forming simulations and process optimization.     

The Thermographic Analysis of the Agglomeration Process in the Roller Press of Pillow-Shaped Briquettes

When the briquetting process of fine-grained material takes place in the roller press unit, the pressure reached is over a hundred megapascals. This parameter is a result, among other factors, of the geometry of a compaction unit and also the properties of the consolidated material. The pressure of the unit is not constant and the changes in value depend on a given place on the molding surface. By the process of generating different types of pressure on the surface of briquettes, their compaction is different as well. The distribution of temperature on the surface of the briquettes may determine the pressure used locally on them. Nevertheless, the distribution of stress in the briquetting material is still a subject of scientific study. However, it is known that the pressure exerted on the briquette is different for different compaction systems. The article includes authors’ further thermography studies on the classical pillow-shaped briquetting process (instead of the saddle-shaped ones that were previously conducted) of four materials (calcium hydroxide and water mixture, mill scale, charcoal fines and starch mixture, as well as a mixture of EAFD, scale, fine coke breeze, molasses, and calcium hydroxide). Immediately after the briquettes left the compaction zone, thermal images were taken of them, as well as forming rollers. Thermograms that were obtained and the variability of temperature at characteristic points of the surface of pillow-shaped briquettes were analyzed. They showed differences in temperature on the surface of briquettes. In all four cases, the highest briquette temperatures were recorded in their upper part, which proves their better densification in this part. The temperature differences between the lower and upper part of the briquettes ranged from 1.8 to 9.7 °C, depending on the mixture.     

智能型婴儿保暖被对极低出生体重儿入室体温及并发症的影响

目的 探讨智能型碳纤维婴儿保暖包被在极低出生体重儿出生后转运环节中的应用效果及对入室体温和预后产生的影响.方法 将125例极低出生体重儿按照随机原则分为研究组62例和对照组63例,对照组采取传统的保暖措施,即新生儿出生后立即置于辐射保温台上,用预热的毛巾擦干身体,移去湿巾,戴帽,护理完毕后用传统婴儿包被包裹送往NICU,研究组在常规保暖的基础上使用智能型碳纤维婴儿保暖包被,比较两组极低出生体重儿入室时的直肠温度和住院期间并发症及转归情况.结果 研究组入室体温低于35℃和35 ～ 36℃者分别为0,19例均低于对照组（11,31例）,两组比较差异有统计学意义（P＜0.01）;研究组入室中位体温36.3℃,明显高于对照组35.5℃,两组比较差异有统计学意义（Z=31.13,P＜0.05）;研究组极低出生体重儿入室时的pH值和BE值比对照组高,差异有统计学意义（x2值分别为4.18,5.01;P＜0.05）;研究组低血糖发生率1.6％ （1/62）、颅内出血发生率14.5％（9/62）,对照组分别为12.7％（8/63）,30.2％ （19/63）,两组比较差异有统计学意义（x2值分别为5.57,4.40;P＜0.05）;研究组住院天数中位数39 d,对照组为46 d,两组比较差异有统计学意义（Z=4.428,P＜0.05）;两组病死率比较差异无统计学意义（x2=0.573,P＞0.05）.在研究过程中研究组未发生体温过高（体温＞37.5℃）及皮疹等不良反应.结论 使用智能型婴儿保暖被可降低极低出生体重儿入室低体温的发生率,降低其并发症的发生,缩短住院日,适合极低出生体重儿的转运.     

64层螺旋CT多平面图像重组对脊柱骨折的术前评估

目的探讨64层螺旋CT多平面图像重组技术对脊柱骨折的诊断价值。方法回顾性分析59例脊柱骨折患者术前64层螺旋CT影像资料,分析多平面图像重组技术显示骨折的能力。结果 59例,共76个椎节骨折,其中T11-L2受累最高,占总数的77.6%。颈椎骨折3例,胸椎骨折16例,腰椎骨折33例,胸腰椎骨折8例。≥2柱以上累计62个椎节(81.6%),其中高处坠落伤和车祸伤分别为15个(24.2%)和39个(64.9%)。CT横断位和多平面重组显示骨折能力有差异性。多平面重组技术可充分显示骨折线的走向和骨折碎片移位情况。结论车祸伤易导致脊柱爆裂性骨折。64层螺旋CT多平面后处理成像技术与横断面扫描技术相互补充,能很好地显示脊柱的3柱结构、爆裂骨折和椎管狭窄程度,能较好显示胸腰段后方韧带复合体的稳定性,对术前骨折分类、指导手术有重要临床意义。     

数字体层图像后处理方法对检测肺结节准确性的影响

目的 探讨数字体层图像两种后处理方法(位移叠加法与滤波反投影法)对肺结节检测准确性的影响。方法 采集经CT证实的50例肺部结节患者的数字体层图像,采用滤波反投影法和位移叠加法进行后处理。由3名不同年资的放射诊断医师阅片并记录评分结果。102个CT证实的结节按直径分为3组:＜5 mm、5~10 mm、>10 mm组;按密度分为实性密度组及毛玻璃密度组。对两种处理方法检出的肺结节进行统计分析。结果 位移叠加法检出肺结节52个,滤波反投影法检出86个,差异有统计学意义(P＜0.001)。对于直径＜5 mm和5~10 mm组,滤波反投影法检出的肺结节数均多于位移叠加法(P=0.001、0.005)。结节直径>10 mm时两种方法的检出数量差异无统计学意义(P=0.317)。在不同密度组中,滤波反投影法检出的结节亦较多,与位移叠加法差异有统计学意义(P均<0.05)。结论 滤波反投影法对检出直径≤10 mm的肺结节、实性结节和毛玻璃结节均优于位移叠加法。     

超低剂量下不同迭代重建技术在肺动脉成像中的优化

目的 探讨不同迭代重建技术在超低剂量肺动脉成像中的应用价值。方法 对30例临床疑似肺动脉栓塞患者行CT肺动脉成像,扫描采用80 kV管电压并开启自动管电流调制技术,分别采用滤波反投影法(FBP)、iDOSE⁴、迭代模型重建(IMR)重建图像。采用5分制评价肺动脉主干及其分支的图像质量,测量计算图像噪声值、SNR、CNR,记录CT容积剂量指数(CTDIvol)、剂量长度乘积(DLP)、计算有效剂量(ED)。比较不同重建技术图像噪声、SNR、CNR及主观图像质量。结果 30例患者的平均体质量指数(BMI)为(25.12±2.48)kg/m²;平均CTDIvol为(0.78±0.28)mGy;平均DLP为(30.46±11.34)mGy·cm,平均ED为(0.43±0.16)mSv。IMR、iDOSE⁴、FBP图像噪声依次增高(P<0.05),SNR、CNR依次降低(P<0.05),CT值差异无统计学意义(P>0.05)。IMR、iDOSE⁴图像的主观评分显著高于FBP(P<0.05);IMR、iDOSE⁴图像可诊断率高于FBP(P<0.05),IMR图像优良率高于iDOSE⁴(P<0.05)。结论 采用80 kV联合IMR可保证肺动脉成像较高的图像质量,同时大大降低患者辐射剂量。     

双能量CT虚拟平扫对胰腺的显示:与真实平扫对比

目的 比较第二代双源双能量CT胰腺虚拟平扫（VNC）和真实平扫（TNC）的图像质量。方法 采用Siemens第二代双源双能量CT对21例怀疑胰腺病变的患者行腹部增强扫描,包括单能量TNC图像、胰腺实质期及门静脉期图像,后处理得到胰腺实质期及门脉期的虚拟平扫（VNCp、VNCv）图像。比较TNC、VNCp、VNCv图像的胰腺病灶、胰腺实质、肝脏、竖脊肌、腹主动脉及门静脉的CT值、噪声、CNR、主观评分。结果 TNC、VNCp、VNCv图像主观评分均满足诊断要求（P=0.150）。与TNC图像比较,VNC图像噪声明显减低（P<0.001）。胰腺实质的CT值在VNCv与TNC图像上差异无统计学意义（P=0.063）。胰腺囊性与实性病灶的CT值在VNCp、VNCv、TNC图像上差异均无统计学意义（P=0.277、0.799）。囊性病灶的CNR在VNCp最高。结论 第二代双源双能量CT对胰腺扫描的VNC图像质量接近TNC,并且可减少辐射剂量。     

不同温度标本对LH750血细胞分析仪检测单核细胞的影响

目的：探讨不同温度标本对 L H750血细胞分析仪检测单核细胞的影响。方法对20例患者各采集3份血标本,分别置于5℃、15℃、25℃恒温下保存30 min ,对EDTA‐K2抗凝全血标本的单核细胞百分比应用L H750进行检测,同时由3名能熟练进行细胞形态检验的工作人员制作血涂片进行检测。结果标本温度越低,L H750检测的单核细胞百分比越高,温度与检测结果呈负相关。5℃及15℃恒温下L H750检测的单核细胞百分比显著高于手工显微镜检测结果（ P＜0．01）,25℃下L H750检测的单核细胞百分比与手工显微镜检测结果比较差异无显著性（P＞0．05）。结论不同温度标本对LH750检测的单核细胞百分比有显著影响,血标本温度为25℃时检测单核细胞百分比更准确。     

消费者信息处理模式在高血压健康教育信息的临床应用1）

[目的]探讨消费者信息处理(CIP)模式在高血压健康教育信息的临床应用效果。[方法]筛选160例高血压病病人,分为观察组与对照组各80例,对照组采用常规健康教育方法,观察组在常规健康教育方法的基础上发放基于 CIP 模式构建的“健康教育手册”,对两组病人出院前发放健康教育满意度调查表,比较两组病人的得分。[结果]观察组病人满意度各项得分明显高于对照组(P<0.01)。[结论]采用CIP模式构建的“健康教育手册”有效提高了高血压健康教育信息的质量,提高了临床健康教育工作的质量和满意度。     

ICU患者体温测量方法现状分析

目的分析重症监护病房(intensive care unit,ICU)体温监测现状,为进一步探讨危重患者最佳体温测量方法提供参考。方法 2013年1月,便利抽样法选取北京、上海、成都、乌鲁木齐等地5所三级甲等医院的35个ICU为研究对象,实地调查ICU监测患者体温所采用的工具、测量部位及方法等。结果 35个ICU中,用水银体温计测量腋窝温度的使用率为91.43%;用监护仪配备的体温监测导线持续监测直肠内温度的使用率为2.86%;用红外线温度扫描仪分次测量额温的使用率为2.86%。结论目前三级甲等医院ICU多以水银体温计间歇测量腋窝温度作为体温测量的主要方法,应尽快找到更好的体温测量工具和部位,并实现持续监测。