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71.
This paper reports a technique for heat conduction isothermal microcalorimeters, which allows, by means of a lowering apparatus, the sample and reference ampoules to be lowered very slowly from the pre-equilibration position to the measuring position. The purpose is to minimize the effect on (total) equilibration time arising from both the pre-equilibration time and the dissipation time (i.e. the time to dissipate the thermal shock which occurs when the vessels are lowered manually). Measurements using 3 ml glass ampoules filled with water, as sample and reference, at 25 and 60 °C, showed that the extent of thermal shock was drastically diminished as the lowering speed decreased, and that the associated heat quantity was reduced to less than 0.2 mJ when lowering occurred over a period of more than 180 s. The dissipation time, the time-period required to dissipate the thermal shock, was also shortened to less than 10 min; the standard manual lowering procedure dissipation time being ca. 25 min. In practice experimental measurements of the imidazole catalysed hydrolysis of triacetin and of the solid state oxidation of ascorbic acid showed that the dissipation time was not shortened when the initial power observed was more than 5 μW, however, it was significantly shortened when the initial power observed was around ≤1 μW. The proposed ampoule lowering procedure could be expected to bring about a saving in the total measurement time for reactions with low initial power, such as those associated with long-term stability studies of relatively stable pharmaceuticals. The described procedure also eliminates operator-induced effects associated with manual lowering of ampoules. In principle the device described also would permit automated loading protocols to be developed.  相似文献   
72.
We present a deterministic model for an age-structured population dynamics taking into account females' pregnancy, maternal care of offsprings, and environmental pressure with or without spatial migration. The model is based on the age-density notion for a group formed by a mother and her offsprings under maternal care. A harmonic-mean-type mating function of sexes without formation of permanent pairs is used. It is assumed that each sex has the pre-reproductive, reproductive, and post-reproductive age intervals. All adult individuals are divided into males, single females, fertilized females, and females taking child care. Individuals of post-reproductive age belong to the group of singles. All individuals of pre-reproductive age are divided into the young and juvenile groups. Only young offsprings are assumed to be under maternal care. Juvenile individuals can live without maternal care. The model consists of integro-PDEs subject to the conditions of integral type. The existence and uniqueness theorem is proved in the case of unlimited population. Separable solutions and their long-time behavior are studied for the limited nondispersing population. In the case of random migration two types of separable solutions and their long-time behavior for the homogeneous Dirichlet and Neumann boundary conditions are studied. In the case of directed migration in one-dimensional domain with special initial and Dirichlet boundary conditions, the unlimited invasive population dynamics is studied. In particular, an explicit formula for the migration front is given.  相似文献   
73.
A plasticized poly(vinyl chloride) (PVC) has the advantage of low cost, long-term stability and flame resistance among other commodity plastic, and has been in service as a product in railway field. However, the transition of the plasticizer concentration through the degrading condition and its relationship with the mechanical properties, the molecular motion, the appearance of surface and other properties was not clear. These relationships were studied by means of Rheovibron, pulse NMR, GC/MS, GPC, SEM and other methods. The bulk properties show similar change between weathering and thermal aging. In addition, the molecular chain was little influenced, however, the plasticizer concentration shows obviously different transition through each phase of aging conditions. According to the results of the observation of surface and section, different appearances between weathering and thermal aging were indicated and these appearances closely relate to the bulk properties. In conclusion, through the weathering condition, a stepwise flow out of inorganic components and plasticizer was presumable to be a main mechanism of the degradation. On the other hand, through the thermal aging condition, the rearrangement and aggregation of the molecular chain by the annealing effect were conceivable as the main mechanism of the degradation.  相似文献   
74.
《Electrophoresis》2018,39(16):2131-2135
An electrochemical sensor for the detection of glucose using thread‐based electrodes and fabric is described. This device is relatively simple to fabricate and can be used for multiple readings after washing with ethanol. The fabrication of the chip consisted of two steps. First, three thread‐based electrodes (reference, working, and counter) were fabricated by painting pieces of nylon thread with either layered silver ink and carbon ink or silver/silver chloride ink. The threads were then woven into a fabric chip with a beeswax barrier molded around the edges in order to prevent leaks from the tested solutions. A thread‐based working electrode consisting of one layer of silver underneath two layers of carbon was selected to fabricate the final sensor system. Using the chip, a PBS solution containing glucose oxidase (GOx) (10 mg/mL), potassium ferricyanide (K3[Fe(CN)6]) (10 mg/mL) as mediator, and different concentrations of glucose (0‐25 mM), was measured by cyclic voltammetry (CV). It was found that the current output from the oxidation of glucose was proportional to the glucose concentrations. This thread‐based electrode system is a viable sensor platform for detecting glucose in the physiological range.  相似文献   
75.
A simple method for the simultaneous determination of personal care product ingredients: galaxolide, tonalide, oxybenzone, 4‐methylbenzyliden camphor, padimate‐o, 2‐ethylhexyl methoxycinnamate, octocrylene, triclosan, and methyl triclosan in lettuce by ultrasound‐assisted extraction combined with solid‐phase microextraction followed by gas chromatography with mass spectrometry was developed. Lettuce was directly extracted by ultrasound‐assisted extraction with methanol, this extract was combined with water, extracted by solid‐phase microextraction in immersion mode, and analyzed by gas chromatography with mass spectrometry. Good linear relationships (25–250 ng/g, R> 0.9702) and low detection limits (1.0–25 ng/g) were obtained for analytes along with acceptable precision for almost all analytes (RSDs < 20%). The validated method was applied for the determination of personal care product ingredients in commercial lettuce and lettuces grown in soil and irrigated with the analytes, identifying the target analytes in leaves and roots of the latter. This procedure is a miniaturized and environmentally friendly proposal which can be a useful tool for quality analysis in lettuce.  相似文献   
76.
An NH -ISFET sensor based on PVC membrane technology with improved long-term stability has been developed. As a new approach, the plasticizer (tetra-n-undecyl) 3,3′,4,4′ -benzhydroltetracarboxylate (ETH2112) was used in membrane preparation. Its lipophilic nature provides a restricted diffusion of the membrane components to the external solution and improves membrane adhesion to the gate area of the ISFET. The good performance of this plasticizer was confirmed by comparison with usual plasticizers applied in standard ISE technology. Moreover, the durability and stability of the sensor were enhanced by the application of a graphite-epoxy layer as an internal reference between the gate area and the PVC membrane. This composite layer permits the reduction of the optical sensitivity and improves the adherence of the PVC membrane to the ISFET surface. Furthermore, this composite layer acts as a plug, preventing the entrance of water upon the encapsulant-chip interface, thus protecting electrical connections from moisture. As a result, an NH -ISFET with a long-term stability of three months and a sensitivity of −58.7 ± 2.3 mV decade−1 in a linear range of 10−5 −0.1 mol dm−3 has been developed. The application of this sensor to a continuous-flow system has confirmed the feasibility of the technological approach proposed.  相似文献   
77.
医院护理信息管理系统运用使用两年,体会到系统的科学性,先进性,可靠性,实用性,法律效应性,对缩短护理工作办公流程,增加护士护理时间,和护理差错,提高护理质量,增加医护人员及病人的双满意效应均具有重要作用。  相似文献   
78.
复方有机锗(Ge-132)兽用保健促长剂(肥猪宝)是将有机锗(Ge-132)创造性地应用在动物饲养上,在总结国内外先进专利技术基础上,经反复实验,开发出新一代动物保健型促长剂。具有增强免疫功能,促进细胞分裂及组织生长等作用,且不同于传统添加剂多数含抗生素,维生素及动物激素等。其特点是抗病防病能力强,生长迅速,肉料比高,且能防治生猪腹泻。本产品经四家养猪场对照实验,效果显著,日平均多增重193克比国  相似文献   
79.
ObjectiveTo evaluate the long-term improvement of clinical symptoms of adenomyosis after treatment with ultrasound-guided high intensity focused ultrasound (USgHIFU).MethodsFrom January 2010 to December 2011, 350 patients with adenomyosis were treated with USgHIFU. Among the 350 patients, 224 of them completed the two years follow-up. The patients were followed up at 3 months, 1 year, and 2 years after HIFU treatment. Adverse effects and complications were recorded.ResultsAll patients completed HIFU ablation without severe postoperative complications. 203 of the 224 patients who showed varying degrees of dysmenorrhea before treatment had the symptom scores decreased significantly after treatment (P < 0.001). The relief rate was 84.7%, 84.7%, and 82.3%, respectively at 3 months, 1 year, and 2 years after treatment. The menstrual volume in 109 patients with menorrhagia was significantly improved after treatment (P < 0.001) with a relief rate of 79.8%, 80.7%, and 78.9%, respectively at 3 months, 1 year, and 2 years after HIFU treatment.ConclusionWith its ability to sustain long-term clinical improvements, HIFU is a safe and effective treatment for adenomyosis.  相似文献   
80.
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