蓝莓浓缩汁流变特性及化学组成的变化

流体的流变学可为工艺设计提供有关数据,并有助于找出产品组成及加工工艺对流变性质的影响。本研究采用AR1000型流变仪研究了浓缩蓝莓汁(60°Brix)在(20～60℃)范围内的流变特性。通过回归分析发现,在研究的温度和浓度范围内,浓缩蓝莓汁表现为牛顿型流体,温度对粘度的影响可用阿雷尼乌斯(Arrhenius)方程来表示,浓度对粘度的影响可用指数方程来表示。推导出了温度和浓度对浓缩蓝莓汁粘度综合影响的方程式并比较了浓缩前后蓝莓汁化学组成的变化。     

固溶体催化剂在CO2加氢制甲醇反应中的应用

固溶体由于产生了固溶强化等性能的变化,使其较单一组分金属的热稳定性、结构性能等方面有着显著的提升,因此在催化剂中具有广阔的应用前景.针对固溶体催化剂在CO2加氢制甲醇反应中的应用,从固溶体的性质、制备方法等方面展开了综述,重点对反应机理和提高催化活性的措施进行了总结,对存在的问题进行了探讨.最后对固溶体催化剂在CO2加氢制甲醇领域的研究方向进行了展望,并认为固溶体催化剂有望为CO2资源化利用各类反应中催化剂的研发提供一种新范式.     

铁矿石粉循环流化床煤基直接还原的实验研究

在小型循环流化床中对铁矿石粉在氮气气氛下用大同煤粉直接还原进行了实验研究,在800~950℃考察了反应温度对铁矿石粉的还原程度及还原产物微观结构的影响. 结果表明,随反应温度提高,铁矿石粉还原产物的金属化率及还原度均增加,800~850℃时增幅较大,850~900℃时增幅平缓,900~950℃时又出现较大增幅,950℃时达到63%的金属化率和87%的还原度;与还原前的铁矿石粉相比,还原产物的比表面积和总孔体积在800℃时均增加,而在其他温度时均减小,对应的平均孔径变化规律则相反.     

油田管材的SRB腐蚀

通过浸泡挂片试验,用扫描电镜和X衍射仪,对试样的腐蚀特征和腐蚀产物进行研究,发现脱硫脱硫弧菌duselfovibrio desulfuricans(D.desulf)对油田管材的腐蚀特征为点蚀,腐蚀产物为Fe9S8,同时通过电化学实验,研究了D.desulf的去极化作用,发现D.desulf的存在既有阳极去极化作用,又有阴极去极化作用。在对D．desulf的生长特性研究中,发现D.desulf的生长存在着对数生长期、生长旺盛期和衰亡期。     

浅谈核安全文化体系的建立与完善

通过对核电设备制造企业核安全文化存在问题的探讨,提出核安全文化体系建立的设想,并提出推动核安全文化体系完善的一些建议。     

Numerical Simulation of Heat Transfer and Deformation of Initial Shell in Soft Contact Continuous Casting Mold Under High Frequency Electromagnetic Field

  Heat transfer and deformation of initial solidification shell in soft contact continuous casting mold under high frequency electromagnetic field were analyzed using numerical simulation method; the relative electromagnetic parameters were obtained from the previous studies. Owing to the induction heating of a high frequency electromagnetic field (20 kHz), the thickness of initial solidification shell decreases, and the temperature of strand surface and slit copper mold increases when compared with the case without the electromagnetic filed. The viscosity of flux decreases because of the induction heating of the high frequency electromagnetic field, and the dimension of the flux channel increases with electromagnetic pressure; thus, the deformation behavior of initial solidification shell was different before and after the action of high frequency electromagnetic field. Furthermore, the abatement mechanism of oscillation marks under high frequency electromagnetic field was explained.     

镜头分割在H.264视频压缩编码及视频服务器中的应用

将镜头分割引入H.264编码端,改善其定比率分配帧类型策略,以针对视频内容特性提高编码效果,并提供压缩流的镜头句柄.提出结合时空切片的信息熵度量帧差、以动态阈值探测镜头边界指定为I帧,非边界帧为P或B帧优化编码,并补充闪光灯防误判算法.经验证动态阈值和熵度量法查全查准率比基本方法提高近18%和13%;结合编码psnr提高10%压缩率提高20%.镜头分割准确,有效提高编码性能,对压缩域视频分割和视频服务器也将产生重大意义.     

CeO2掺杂TiO2粉体的制备及其性能研究

采用Sol-gel法制备了CeO2不同掺杂比例的TiO2粉体,研究了掺杂比例对样品晶型、光谱吸收曲线及光催化降解亚甲基蓝的影响,结果表明:掺杂CeO2的TiO2样品对光波长的响应阈值为500nm左右;样品在普通日光灯下照射4h,对亚甲基蓝的降解率明显优于Degause P25,其中CeO2掺杂比率为7%(mol)的样品降解率达到了最大.     

SPARC deficiency leads to early-onset cataractogenesis

PURPOSE: To determine the role of SPARC (secreted protein, acidic, and rich in cysteine) in cataractogenesis by examining mice deficient in a matricellular protein SPARC. METHODS: Mice were rendered SPARC-deficient by a targeted disruption of the gene. Slit-lamp microscopy and histology were used to examine the eyes of SPARC-null and wild-type mice from birth to 14 months of age. RESULTS: SPARC-null mice developed opacities in the posterior cortex of the eye as early as 1.5 months after birth. The diffuse cataracts appeared to progress toward the anterior cortex and reached maturity in many animals by 3.5 months of age. Early stages of cataractogenesis in SPARC-null mice included inhibition of normal lens fiber cell differentiation, degeneration of fiber cells, vacuole formation at the equator, and liquefaction of the cortex. No cataracts were detected in wild-type mice up to the age of 8 months. CONCLUSIONS: The early onset of cataracts in SPARC-null mice establishes that the gene is essential to the maintenance of lens transparency.     

Preoperative chemoradiation and pancreaticoduodenectomy for adenocarcinoma of the pancreas

The goal of multimodality therapy for localized pancreatic cancer is to maximize local-regional disease control and patient survival. In contrast to surgery for other solid tumors, prolonged recovery following pancreaticoduodenectomy may prevent the timely delivery of postoperative adjuvant therapy. Therefore, efforts at The University of Texas, M.D. Anderson Cancer Center have focused on the delivery of chemotherapy and radiation therapy prior to surgery in patients with localized pancreatic cancer. Clinical trials have emphasized the use of altered-fractionation schedules of radiation therapy combined with novel radiation-sensitizing agents. All treatment schemes aim to decrease toxicity and treatment time while improving therapeutic efficacy.