模拟现场施工条件,测定了不同温度下灌注袋中的中国铁路轨道系统Ⅰ型水泥乳化沥青(cement and emulsified asphalt,CA)砂浆膨胀率随时间变化,并测定了浆体pH值随时间的变化。研究发现CA砂浆早期膨胀可分为4个阶段:混合后0～3h,砂浆收缩;...模拟现场施工条件,测定了不同温度下灌注袋中的中国铁路轨道系统Ⅰ型水泥乳化沥青(cement and emulsified asphalt,CA)砂浆膨胀率随时间变化,并测定了浆体pH值随时间的变化。研究发现CA砂浆早期膨胀可分为4个阶段:混合后0～3h,砂浆收缩;3～6h,砂浆迅速膨胀;6～10h,砂浆再收缩;10 h以后,砂浆体积较为稳定。温度越高,各阶段开始时间越早,持续时间也越短;20～35℃,浆体膨胀率随温度升高而增大,但温度为35～45℃时,砂浆膨胀率随温度升高反而减小,温度对浆体pH值随时间变化的影响也有类似规律。扫描电子显微镜和能谱仪结果表明:对于水化10d的水泥乳化沥青砂浆,20℃浆体中可看到大量与钙矾石有关的针状物,而55℃浆体中除沥青膜层外,水泥水化产物并不明显。高温下(>35℃)乳化沥青破乳,包裹铝粉与水泥颗粒,使铝粉发气反应受到抑制可能是导致膨胀率、pH值等变化异常的原因。展开更多
A new analytical method for springback of small curvature plane bending is addressed with unloading rule of classical elastic-plastic theory and principle of strain superposition.We start from strain analysis of plane...A new analytical method for springback of small curvature plane bending is addressed with unloading rule of classical elastic-plastic theory and principle of strain superposition.We start from strain analysis of plane bending which has initial curvature,and the theoretic derivation is on the widely applicable basic hypotheses.The results are unified to geometry constraint equations and springback equation of plane bending,which can be evolved to straight beam plane bending and pure bending.The expanding and setting round process is one of the situations of plane bending,which is a bend-stretching process of plane curved beam.In the present study,springback equation of plane bending is used to analyze the expanding and setting round process,and the results agree with the experimental data.With a reasonable prediction accuracy,this new analytical method for springback of plane bending can meet the needs of applications in engineering.展开更多
Apart from water,tea is the world’s most widely consumed beverage.Tea is produced in more than 50 countries with an annual production of approximately 4.7 million tons.The market segment for specialty tea has been ex...Apart from water,tea is the world’s most widely consumed beverage.Tea is produced in more than 50 countries with an annual production of approximately 4.7 million tons.The market segment for specialty tea has been expanding rapidly owing to increased demand,resulting in higher revenues and profits for tea growers and the industry.Accurate varietal identification is critically important to ensure traceability and authentication of premium tea products,which in turn contribute to on-farm conservation of tea genetic diversity.Using a set of single nucleotide polymorphism(SNP)markers developed from the expressed sequence tag(EST)database of Camilla senensis,we genotyped deoxyribonucleic acid(DNA)samples extracted from a diverse group of tea varieties,including both fresh and processed commercial loose-leaf teas.The validation led to the designation of 60 SNPs that unambiguously identified all 40 tested tea varieties with high statistical rigor(p<0.0001).Varietal authenticity and genetic relationships among the analyzed cultivars were further characterized by ordination and Bayesian clustering analysis.These SNP markers,in combination with a high-throughput genotyping protocol,effectively established and verified specific DNA fingerprints for all tested tea varieties.This method provides a powerful tool for variety authentication and quality control for the tea industry.It is also highly useful for the management of tea genetic resources and breeding,where accurate and efficient genotype identification is essential.展开更多
Colorectal cancer (CRC) is the 3<sup>rd</sup> most common cancer in the United States with more than 10000 new cases diagnosed annually. Approximately 20% of patients with CRC will have distant metastasis ...Colorectal cancer (CRC) is the 3<sup>rd</sup> most common cancer in the United States with more than 10000 new cases diagnosed annually. Approximately 20% of patients with CRC will have distant metastasis at time of diagnosis, making them poor candidates for primary surgical resection. Similarly, 8%-25% of patients with CRC will present with bowel obstruction and will require palliative therapy. Emergent surgical decompression has a high mortality and morbidity, and often leads to a colostomy which impairs the patient’s quality of life. In the last decade, there has been an increasing use of colonic stents for palliative therapy to relieve malignant colonic obstruction. Colonic stents have been shown to be effective and safe to treat obstruction from CRC, and are now the therapy of choice in this scenario. In the setting of an acute bowel obstruction in patients with potentially resectable colon cancer, stents may be used to delay surgery and thus allow for decompression, adequate bowel preparation, and optimization of the patient’s condition for curative surgical intervention. An overall complication rate (major and minor) of up to 25% has been associated with the procedure. Long term failure of stents may result from stent migration and tumor ingrowth. In the majority of cases, repeat stenting or surgical intervention can successfully overcome these adverse effects.展开更多
文摘模拟现场施工条件,测定了不同温度下灌注袋中的中国铁路轨道系统Ⅰ型水泥乳化沥青(cement and emulsified asphalt,CA)砂浆膨胀率随时间变化,并测定了浆体pH值随时间的变化。研究发现CA砂浆早期膨胀可分为4个阶段:混合后0～3h,砂浆收缩;3～6h,砂浆迅速膨胀;6～10h,砂浆再收缩;10 h以后,砂浆体积较为稳定。温度越高,各阶段开始时间越早,持续时间也越短;20～35℃,浆体膨胀率随温度升高而增大,但温度为35～45℃时,砂浆膨胀率随温度升高反而减小,温度对浆体pH值随时间变化的影响也有类似规律。扫描电子显微镜和能谱仪结果表明:对于水化10d的水泥乳化沥青砂浆,20℃浆体中可看到大量与钙矾石有关的针状物,而55℃浆体中除沥青膜层外,水泥水化产物并不明显。高温下(>35℃)乳化沥青破乳,包裹铝粉与水泥颗粒,使铝粉发气反应受到抑制可能是导致膨胀率、pH值等变化异常的原因。
基金supported by the National Natural Science Foundation of China(Grant No.50805126)the Natural Science Foundation of Hebei Province(Grant No.E2009000389)
文摘A new analytical method for springback of small curvature plane bending is addressed with unloading rule of classical elastic-plastic theory and principle of strain superposition.We start from strain analysis of plane bending which has initial curvature,and the theoretic derivation is on the widely applicable basic hypotheses.The results are unified to geometry constraint equations and springback equation of plane bending,which can be evolved to straight beam plane bending and pure bending.The expanding and setting round process is one of the situations of plane bending,which is a bend-stretching process of plane curved beam.In the present study,springback equation of plane bending is used to analyze the expanding and setting round process,and the results agree with the experimental data.With a reasonable prediction accuracy,this new analytical method for springback of plane bending can meet the needs of applications in engineering.
基金This work was partially supported by the National Natural Science Foundation of China(30800884,31370688)References to a company and/or product by the USDA are only for the purposes of information and do not imply approval or recommendation of the product to the exclusion of others that may also be suitable.
文摘Apart from water,tea is the world’s most widely consumed beverage.Tea is produced in more than 50 countries with an annual production of approximately 4.7 million tons.The market segment for specialty tea has been expanding rapidly owing to increased demand,resulting in higher revenues and profits for tea growers and the industry.Accurate varietal identification is critically important to ensure traceability and authentication of premium tea products,which in turn contribute to on-farm conservation of tea genetic diversity.Using a set of single nucleotide polymorphism(SNP)markers developed from the expressed sequence tag(EST)database of Camilla senensis,we genotyped deoxyribonucleic acid(DNA)samples extracted from a diverse group of tea varieties,including both fresh and processed commercial loose-leaf teas.The validation led to the designation of 60 SNPs that unambiguously identified all 40 tested tea varieties with high statistical rigor(p<0.0001).Varietal authenticity and genetic relationships among the analyzed cultivars were further characterized by ordination and Bayesian clustering analysis.These SNP markers,in combination with a high-throughput genotyping protocol,effectively established and verified specific DNA fingerprints for all tested tea varieties.This method provides a powerful tool for variety authentication and quality control for the tea industry.It is also highly useful for the management of tea genetic resources and breeding,where accurate and efficient genotype identification is essential.
基金Supported by(Entirely)Thomas Jefferson University HospitalUniversity of Utah through existing intramural funds and salary support
文摘Colorectal cancer (CRC) is the 3<sup>rd</sup> most common cancer in the United States with more than 10000 new cases diagnosed annually. Approximately 20% of patients with CRC will have distant metastasis at time of diagnosis, making them poor candidates for primary surgical resection. Similarly, 8%-25% of patients with CRC will present with bowel obstruction and will require palliative therapy. Emergent surgical decompression has a high mortality and morbidity, and often leads to a colostomy which impairs the patient’s quality of life. In the last decade, there has been an increasing use of colonic stents for palliative therapy to relieve malignant colonic obstruction. Colonic stents have been shown to be effective and safe to treat obstruction from CRC, and are now the therapy of choice in this scenario. In the setting of an acute bowel obstruction in patients with potentially resectable colon cancer, stents may be used to delay surgery and thus allow for decompression, adequate bowel preparation, and optimization of the patient’s condition for curative surgical intervention. An overall complication rate (major and minor) of up to 25% has been associated with the procedure. Long term failure of stents may result from stent migration and tumor ingrowth. In the majority of cases, repeat stenting or surgical intervention can successfully overcome these adverse effects.
