阳离子淀粉包覆改性硅藻土制备及在造纸中应用研究

以阳离子淀粉和硅藻土为主要原料,采用阳离子淀粉对硅藻土进行改性,并将其用于造纸填料中.研究了阳离子淀粉改性硅藻土颗粒形态、Zeta电位、粒径、阳离子淀粉沉积率和改性硅藻土留着率的变化.结果表明,采用阳离子淀粉和三偏磷酸钠能有效对硅藻土进行改性,使硅藻土粒径增大,Zeta电位升高,淀粉沉积率达98％以上.在同一加入量的条件下,与加入未改性硅藻土纸张相比,加入改性硅藻土纸张的抗张指数、撕裂指数、耐折度和耐破度均有所提高和改善,改性硅藻土留着率超过85％.     

改性钙基膨润土对水泥浆体悬浮性的影响

通过对钙基膨润土(Ca-BT)进行改性,采用X射线衍射(XRD)、扫描电子显微镜(SEM)、激光粒径分布和zeta(ζ)电位进行表征,再结合对水泥浆体泌水率测试,研究了改性膨润土对水泥浆体悬浮性的影响.结果表明:Ca-BT经机械改性后,颗粒粒径显著减小,但对 ζ电位影响不大;Ca-BT经化学改性后 ζ电位绝对值明显增大,由-4.9 mV增至-32.9 mV;Ca-BT经机械化学改性后颗粒粒径明显减小且ζ电位绝对值增大,晶体层状结构破坏部分剥离为单片层,显著提高水泥浆体的悬浮性;在水泥浆体中掺入经机械化学改性的Ca-BT,其中改性剂掺量为7％时,搅拌均匀静置2 h后泌水率为4.46％最低,体系悬浮性最好.     

改性无机填料成分剖析研究

介绍改性无机填料成分的剖析方法。以未知样品x为例,采用裂解一-气相色谱质谱联用仪、红外光谱仪、原子吸收光谱仪、冷场发射扫描电子显微镜及一些常规的化学方法进行测试,确定样品为改性碳酸钙：外层包覆10％左右的脂肪酸盐类物质,中间主体为90％左右的碳酸钙。     

重质碳酸钙在线表面改性对留着率的影响

研究的目的是在对造纸工艺不作重大改变的条件下，用助留剂阳离子淀粉对重质碳酸钙进行在线表面改性，该方法改性的重质碳酸钙能提高其在纤维中的留着率。实验发现，用阳离子淀粉对重质碳酸钙在线进行表面改性，对提高其留着率来说是相当经济的选择。     

重钙的表面改性及在造纸中的应用

对阳离子改性重钙填料进行了研究,并应用于纸体系,改性重钙大大提高了纸张的填料留着率及纸张强度。     

不饱和聚酯包覆层的耐烧蚀性能

采用在不饱和聚酯树脂中填加阻燃剂、耐烧蚀纤维等功能填料的方式来解决不饱和聚酯包覆层烧蚀较高的问题。通过功能填料选择试验,探索出基体材料中加入阻燃剂和耐烧蚀纤维的技术,研究了阻燃剂和耐烧蚀纤维加入量及耐烧蚀纤维长度对烧蚀率的影响。结果表明,增加碳纤维加入量或碳纤维长度,包覆层的线烧蚀率明显降低;氢氧化铝对不饱和聚酯树脂的烧蚀率有一定的贡献。复合改性后包覆层的线烧蚀率为0．252mm／s（改性前为0．653mm／s）,黏度较小,不影响包覆工艺。Ф50mm发动机试验表明,选用复合改性不饱和聚酯树脂包覆层包覆改性双基推进剂,包覆层壳体完整（残留率大于90％）。     

阳离子壳聚糖和羧甲基纤维素对造纸沉淀碳酸钙填料的改性

沉淀碳酸钙(PCC)的改性对提高它在纸中的留着率并减少对纸张强度的负面影响具有重要意义.本文研究了阳离子壳聚糖和羧甲基纤维素对PCC的改性,并分析了PCC改性对其留着率和纸张抗张指数的影响.实验结果表明,阳离子壳聚糖与羧甲基纤维素的质量比为0.56时,聚电解质复合物的浊度最高,在此条件下聚电解质复合物改性的PCC水分散体上清液具有最小的浊度.与未改性PCC相比,改性后PCC在纸中的留着率更高,而且对纸张抗张指数的负面影响更小.     

阳离子淀粉的基本使用技术及其在造纸中的应用

阳离子淀粉是一类较好的造纸湿部化学助剂,主要用作纸张补强剂和造纸填料助留剂,也可用作表面施胶剂等。本文主要阐述了阳离子淀粉的添加对造纸浆料Zeta电位的变化规律及其在纤维上的留着率;阳离子淀粉在造纸工业中的应用效果及其在使用时应注意的几个主要问题,     

硅藻土负载石榴皮提取物抗菌复合材料的制备与研究

为促进石榴皮资源广泛应用,本实验采用超声波提取法对石榴皮进行提取,以硅藻土作为载体负载石榴皮提取物.通过单因素实验得最佳提取条件:乙醇浓度70％,料液比1:15,石榴皮粉过200目筛,超声提取时间30 min,活性成分得率为8.34％.对硅藻土原土和Al(NO3)3改性硅藻土负载石榴皮提取物进行研究,实验得改性硅藻土对石榴皮提取物负载量高于原土,磁力搅拌8 h改性硅藻土负载量为170 mg/g而硅藻原土仅为45 mg/g.利用振荡法进行抗菌检测,发现石榴皮提取物(浓度为0.1 mL石榴皮浸膏/1 mL去离子水)对大肠杆菌和金黄色葡萄球菌具有很好的抑菌效果,37℃恒温振荡10 h抑菌率达100％;改性硅藻土负载石榴皮提取物(浓度为0.1 g/mL)对两种菌种有一定程度的抑制效果,对金黄色葡萄球菌作用较强,37℃恒温振荡10 h抑菌率达100％.对样品进行分析表征:由SEM、BET测试结果可知改性硅藻土表面及内部明显附着物质;由FT-IR分析及实验现象可知改性硅藻土表面及内部物质为石榴皮成分,石榴皮提取物与硅藻土表面Al3+发生络合反应取代硝酸根;由Zeta电位分析可知改性硅藻土与石榴皮提取物之间的静电作用也促进了负载过程,因此改性硅藻土对石榴皮提取物的负载是物理吸附与化学吸附共同作用的结果.     

Ti4+对碳酸钙的表面掺杂包覆改性及其用作造纸填料的研究

采用螯合型钛酸酯偶联剂对沉淀碳酸钙进行改性,将改性产物经550 ℃煅烧,得到改性碳酸钙.对产物进行XRD,XPS,红外分析表征,结果显示:改性的碳酸钙的表面存在有钛酸钙晶体和钛的四价氧化物.将改性碳酸钙用作造纸填料,纸张的白度略有升高,力学性能有一定程度的下降,填料留着率没有发生明显的变化.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。