混合系数线性模型参数的可容许估计

讨论了混合系数线性模型参数估计,给出了完全随机系数的线性模型参数的新估计,证明了这个估计量的可容许性.     

Technology and kinetics of free fatty acids esterification in tung oil

We studied the esterification of free fatty acids （FFA） in tung oil with methanol by using activated carbon treated with sulfuric acid as a catalyst, and investigated the effect of different temperatures, methanol/oil mole ratio and catalyst amount on the conversion of FFA. Results show that the optimal reaction condition is when the reaction time is 2 h, the mass fraction of the catalyst to total material is 5%, the molar ratio of menthol to FFA is 15 ： 1, and the reaction temperature is 368.15 K. We also investigated the kinetics of estefification at various temperatures. Results indicate that the rate-control step could be attributed to the surface reaction, and within the range of the experimental conditions, the as-calculated kinetics formula can depict the esterification processes well.     

处理一般事件及极端事件风险的混合分布

以指数分布为例，提出用混合分布去拟合一组数据，比用单一的指数分 要好，一般的原始分布只对中间部分拟合较好，而对尾部拟合较差，可用混合分布来克服此缺陷。     

Bioleaching of a kind of alkaline mixed copper oxide and sulphide mineral

We conducted two-stage acidification-bioleaching experiments to probe the feasibility of bioleaching for a kind of mixed alkaline copper oxide and sulphide mineral. We used the uniform design method for data analysis and experimental optimization, with initial pH value, pulp density, inoculation of bacteria and ferrous iron concentration selected as the influential factors. Polynomial regression shows that the four factors sequentially influence the copper recovery by 14.430%, 8.555%, 1.982% and 3.895%. Acid equilibrium in the bioleaching system is mainly influenced by alkaline gangue content, chemical reactions and bacterial activity. A maximal portion of refractory copper extracted reaches 71.08%. The dynamic analysis of copper recovery indicates that bioleaching goes through a lag leaching phase, prime leaching phase and leaching stationary phase corresponding to the growth phases of bacteria. Compared with the predicted value of 80.87%, the confirmatory experiment observes a 78.21% copper recovery under the optimal conditions of pH of 1.5, pulp density of 5%, bacteria inoculation of 30% and initial ferrous iron concentration of 9 g L^-1. Results suggest that bioleaching is technically feasible to improving total copper recovery.     

Erratum to:Mass transfer and reaction kinetics of sulfuryl fluoride absorption with aqueous sodium hydroxide solutions

正The original version of this article unfortunately contained two mistakes.In p.544,the square root on the right side o02f Eq.(14)"Ha=(k2DA/(k0LA)2C1/2BL)1/2"and the square root on the right side of Eq.(15)"E=Ha=(k2DA/(k0LA)2C1/2BL)1/2"were incorrect.The correct versions of Eqs.(14)and(15)are given below:     

新型电沉积-生物膜复合工艺处理含Cr3+有机废水

采用新型电沉积 生物膜复合工艺处理含重金属离子 (Cr3 + )有机废水 ,阐述其作用机理 .实验废水中的有机物由生物膜中的复合微生物菌群作为营养源而消耗 ;重金属离子则一部分通过电沉积去除 ,另一部分通过生物膜吸附而去除 ,净化后废水能够达到工业回用水标准 .探讨了培养、驯化后的复合微生物降解有机物动力学速率 ,并将采用复合工艺与单纯的电沉积工艺及生物膜工艺处理含重金属离子有机废水的实验结果进行对比 ,结果表明 ,C6H12 O6含量为 5 0 0mg·L-1及Cr3 + 含量为 10mg·L-1的废水 ,利用复合工艺净化处理后 ,C6H12 O6含量为 2 0— 30mg·L-1,Cr3 + 含量低于 1mg·L-1.     

氢氧化钠溶液吸收硫酰氟的传质反应动力学

研究目的：研究方法：重要结论：确定氢氧化钠溶液化学吸收硫酰氟的传质反应动力学区域,建立增强因子模型。研究气液传质测定设备双搅拌釜中氢氧化钠溶液化学吸收硫酰氟的过程,并结合实验研究与理论分析建立了增强因子模型。基于氢氧化钠溶液化学吸收硫酰氟过程的实验研究,确定了氢氧化钠溶液化学吸收硫酰氟的传质反应动力学区域为快速拟一级反应。得到了298K下其二级反应速率常数为1．44m3／（mol·s）,并建立了增强因子模型E=68．08CBL1/2,为脱除熏蒸后残留硫酰氟的工业化应用提供了理论依据。     

Polymerization of methyl methacrylate with ethylene bridged heterodinuclear metallocene of samarium and titanium-study on synergism and kinetics

Comparison of MMA polymerization results with samarocene chloride, titanocene chloride and the title heterodinuclear (Sm−Ti) catalyst, respectively, showed synergism in the Sm-Ligand-Ti system, which obviously influenced the polymerization behaviors, for example, of yeilding higher activity and higher molecular weight polymer. Kinetic studies on polymerization of MMA with ethylene bridged samarocene and titanocene chloride/Al(i-Bu)₃ showed that the polymerization rate was first-order on the catalyst concentration, and 1.9-order on the monomer. The overall activation energy measured was 52.8 kJ/mol. Project supported by NSFC (No. 20074028), and SINOPEC(X598037).     

Virtual,augmented and mixed reality in K–12 education: a review of the literature

ABSTRACT

This article provides the first review of the existing literature consolidating research into the use of virtual, augmented and mixed reality technologies within K–12 educational environments. The review explores the peer-reviewed scholarly studies conducted between 2006 and May 2017, which involved the use of virtual reality (VR), augmented reality (AR) or mixed reality (MR) technologies in the instruction of students in elementary, middle or high school. The literature revealed common themes including collaboration, communication, critical thinking, attitude, engagement, learning, motivation, performance or achievement, and technology (used or proposed). This literature review will contribute to the field by providing clarity on definitions for VR, AR and MR technologies in consideration of educational use, present an overview of the existing research on VR, AR and MR specific to K–12 educational environments and identify future research needs and directions.     

一类具有正负系数的时滞差分方程的振动性

给出了带有正负系数的二阶差分方程△2[x（k）＋Σi=1^mici（k）x（k-τi）]＋Σi=1^m2pi（k）x（k-δi）-Σi=1^m3qi（k）x（k-σi）=0 k∈N振动的充分条件.     

The emancipatory potential of transformative mixed methods designs: informing youth participatory action research and restorative practices within a district-wide school transformation project

ABSTRACT

This paper considers the emancipatory potential of incorporating youth participatory action research (YPAR) and restorative practices (RP) implementation into a transformative mixed methods study design as a means to create equitable and caring school systems for marginalized youth. The utilization of transformative mixed methods research offers a methodological orientation to legitimize, illuminate, and prioritize perspectives from marginalized youth that may be undervalued, decontextualized, and oversimplified in traditional quantitative and qualitative research methodologies. Furthermore, the authors suggest that YPAR and RP align with Critical Theory and Quantitative Criticalism, which are theoretical and methodological frameworks consistent with the transformative paradigm. The integration of these various theoretical, methodological and applied frameworks provides researchers opportunities to flatten hierarchies and actively engage marginalized youth to address the structural and programmatic inequities they experience in schools. Informed by the authors’ multi-year university-school district action research partnership, this paper explores how the alignment of YPAR, RP, and transformative mixed methods may promote critical consciousness amongst students, families, staff, and administration in schools. Finally, we also demonstrate how social science researchers can blend YPAR, RP, and transformative mixed methods design to partner with school districts to address structural societal problems, such as racism and inequity.     

ZZ-IID型肛肠治疗仪加缝扎法治疗重度混合痔40例临床观察

目的:比较肛肠治疗仪与肛肠治疗仪加缝扎法治疗重度混合痔的治疗效果.方法:将80例混合痔(内痔Ⅲ期)随机分为治疗组(肛肠治疗仪加缝扎法组)和对照组(肛肠治疗仪组),比较分析手术过程,术后效果.结果:手术过程治疗组所需时间长,但术后复发低,优于对照组.结论:现代化的肛肠治疗仪加传统的基底缝扎术是临床上治疗重度混合痔的非常理想的治疗方法.     

Testing the usability of a portable DVD player and tailored photo instructions with older adult veterans

DVD-delivered behavioral skills training may help disseminate efficacious treatments to older adults independent of internet access. The present study examined the usability of a portable DVD player alongside iterative revisions of accompanying instructions to be used by older adults in a DVD-delivered behavioral skills treatment study. The sample comprised 20 older adults with a mean age of 69.5 years (SD = 7.3). Behavior observations revealed that three of five steps to play the DVD were completed by more than 90% of participants. Quantitative ratings revealed that 75% could play the DVD easily. Qualitative content analysis further elucidated the usability of the player and the clarity of the instructions. Findings suggest user-centered design of instructional support in DVD-delivered treatments for older adults may be critical to minimizing user error and frustration and increase user experience.     

粉煤灰掺量对高性能混凝土强度和工作性的影响

大量的工程实践表明 ,粉煤灰是配制高性能混凝土的重要组分之一 :增加粉煤灰掺量 ,能够明显改善混凝土的工作性 ,也利于配制泵送混凝土 ;高掺量粉煤灰混凝土的后期强度增长幅度较大     

Towards a re-conceptualization of teachers' self-efficacy beliefs: tackling enduring problems with the quantitative research and moving on

Various commentators have argued for years that the study of teachers' self-efficacy (TSE) beliefs, largely dominated by quantitative research methodologies, has been confused. Contentious issues include the very conceptualization of these beliefs, how they are defined and accessed through research and how the research is used. One of the biggest anomalies is that, despite claiming that these beliefs are task-specific, many quantitative researchers have both assessed them globally and portrayed them as hard to impact. In contrast, some qualitative researchers have emphasized the task-specific nature of these beliefs and their potential for transformation through self-doubt, reflection and learning. This literature review examines these and other contentious issues, focusing on studies published in international peer-reviewed journals in the last few years, looking, through the use of search terms and the surveying of abstracts followed by detailed reading, for evidence of developing understandings and changing research practices. This review highlights continuing misalignment between theory and method in much of the literature, but also identifies promising research directions. Mixed methods and qualitative research designs seem to have the potential to produce insightful findings that can make the study of TSE beliefs of greater use to teacher educators than has previously been the case.     

Treatment and prognosis of cervical cancer associated with pregnancy: analysis of 20 cases from a Chinese tumor institution

This study was designed to investigate the therapeutic approaches and prognosis for cervical cancer associated with pregnancy. Clinical information, therapeutic strategies, and follow-up results of 20 patients with cervical cancer associated with pregnancy from Jan. 2000 to June 2009 in the Zhejiang Cancer Hospital were retrospectively analyzed. The International Federation of Gynecology and Obstetrics (FIGO) stages were: in situn=1), stage IA1 n=1), stage IB1 n=5), stage IB2 n=1), stage IIA n=8), stage IIB n=3), and stage IIIB n=1). Eight patients were in the first trimester of pregnancy, four in the second, two in the third, and six at postpartum when diagnosed. The therapeutic strategies were either single or combined modalities, including surgery, radiotherapy, and chemotherapy. Fourteen patients survived, five patients died (four of remote metastasis and one of uremia), and one patient was lost to follow-up. One newborn from a patient at stage IIA carcinoma in the third trimester with postponed therapy six weeks after diagnosis survived. Retarded fetal growth was observed in one patient receiving neoadjuvant chemotherapy and cesarean section. Out of the six postpartum patients, three underwent cesarean section and survived, whereas only one out of the three who underwent vaginal delivery survived. The remaining two died of remote metastasis. Therefore, personalized treatment is necessary for cervical cancer associated with pregnancy. Cervical cancer patients in the third trimester of pregnancy can continue the pregnancy for a short period of time. There may be potential risk for the fetus by chemotherapy during pregnancy. Cesarean section is the preferred mode of delivery for pregnant cervical cancer patients.     

Treatment of 140 cerebral palsied children with a combined method based on traditional Chinese medicine （TCM） and western medicine

Objective:To observe and evaluate a method that is effective and practical for treatment of cerebral palsied(CP)children in China.Method:The patient's age and disease type and individual specific conditions were considered in choosingtherapy methods accordingly:Chinese herbs,acupuncture,auricnlar seed pressure,point finger pressing,massage,orthopedichand manipulation,physiotherapy,occupational therapy,language therapy,etc.Meanwhile we created a new CP treatment modelthat combines hospitalized treatment with family therapy.Results:The majority of CP patients improved greatly in motor andsocial adaptation capacities after treatment.Wilcoxon paired rank sum test analysis showed that there were significant differencesbetween the data before and after treatment(P＜0.01).Conclusion:This combined therapy method,based on traditional Chinesemedicine and western medicine plus family supplemental therapy,is an effective and practical treatment strategy for CP children inChina.