Simplified quantitative analysis method and its application in the insitu synthesized copper-based azide chips

Copper-based azide(Cu(N_(3))2 or CuN_(3),CA)chips synthesized by in-situ azide reaction and utilized in miniaturized explosive systems has become a hot research topic in recent years.However,the advantages of in-situ synthesis method,including small size and low dosage,bring about difficulties in quantitative analysis and differences in ignition capabilities of CA chips.The aim of present work is to develop a simplified quantitative analysis method for accurate and safe analysis of components in CA chips to evaluate and investigate the corresponding ignition ability.In this work,Cu(N_(3))2 and CuN_(3)components in CA chips were separated through dissolution and distillation by utilizing the difference in solubility and corresponding content was obtained by measuring N_(3)-concentration through spectrophotometry.The spectrophotometry method was optimized by studying influencing factors and the recovery rate of different separation methods was studied,ensuring the accuracy and reproducibility of test results.The optimized method is linear in range from 1.0-25.0 mg/L,with a correlation coefficient R^(2)=0.9998,which meets the requirements of CA chips with a milligram-level content test.Compared with the existing ICP method,component analysis results of CA chips obtained by spectrophotometry are closer to real component content in samples and have satisfactory accuracy.Moreover,as its application in miniaturized explosive systems,the ignition ability of CA chips with different component contents for direct ink writing CL-20 and the corresponding mechanism was studied.This study provided a basis and idea for the design and performance evaluation of CA chips in miniaturized explosive systems.

Rapid fabrication of modular 3D paper-basedmicrofluidic chips using projection-based 3D printing

Paper-based microchips have different advantages,such as better biocompatibility,simple production,and easy handling,making them promising candidates for clinical diagnosis and other fields.This study describes amethod developed to fabricate modular three-dimensional(3D)paper-based microfluidic chips based on projection-based 3D printing(PBP)technology.A series of two-dimensional(2D)paper-based microfluidic modules was designed and fabricated.After evaluating the effect of exposure time on the accuracy of the flow channel,the resolution of this channel was experimentally analyzed.Furthermore,several 3D paper-based microfluidic chips were assembled based on the 2D ones using different methods,with good channel connectivity.Scaffold-based 2D and hydrogel-based 3D cell culture systems based on 3D paper-based microfluidic chips were verified to be feasible.Furthermore,by combining extrusion 3D bioprinting technology and the proposed 3D paper-based microfluidic chips,multiorgan microfluidic chips were established by directly printing 3D hydrogel structures on 3D paperbased microfluidic chips,confirming that the prepared modular 3D paper-based microfluidic chip is potentially applicable in various biomedical applications.

Advances in microfluidic chips based on islet hormone-sensing techniques

Diabetes mellitus is a global health problem resulting from islet dysfunction or insulin resistance.The mechanisms of islet dysfunction are still under investigation.Islet hormone secretion is the main function of islets,and serves an important role in the homeostasis of blood glucose.Elucidating the detailed mechanism of islet hormone secretome distortion can provide clues for the treatment of diabetes.Therefore,it is crucial to develop accurate,real-time,laborsaving,high-throughput,automated,and cost-effective techniques for the sensing of islet secretome.Microfluidic chips,an elegant platform that combines biology,engineering,computer science,and biomaterials,have attracted tremendous interest from scientists in the field of diabetes worldwide.These tiny devices are miniatures of traditional experimental systems with more advantages of timesaving,reagent-minimization,automation,high-throughput,and online detection.These features of microfluidic chips meet the demands of islet secretome analysis and a variety of chips have been designed in the past 20 years.In this review,we present a brief introduction of microfluidic chips,and three microfluidic chipsbased islet hormone sensing techniques.We focus mainly on the theory of these techniques,and provide detailed examples based on these theories with the hope of providing some insights into the design of future chips or whole detection systems.

社会资本与中国农村养老保险——基于CHIPS数据的实证研究

党的十八大以来,习近平总书记多次发表重要论述,阐明自己的"民生观",指出中国养老问题的重要性。改革开放以来,中国经济、社会、政治都发生了巨大变化。福利一词也越来越多为人所谈论。本文以农村养老保险为切入口,研究社会资本、党员身份与农村养老保险的参与程度、知情程度、未来参与意愿之间的关系,从一个侧面反映中国农村的福利情况。通过文献综述,提出了六个假设。根据中国家庭收入调查(CHIPS)数据,建立Logistic回归模型,发现社会资本对是否参加农村养老保险、是否知道个人账户有多少钱、将来是否加入农村养老保险都有积极作用;党员身份与是否参加农村养老保险、是否知道自己的个人账户有多少钱、将来是否可能参加无关。结果表明,提高村民的社会资本,加强他们的社会交往有助于他们获取信息,改善福利,所以可以提高村民小组活动和村民大会的频率以增加农民的社会资本。

CHIPS教学理念在药理学教学中的应用

CHIPS是一种新型的培养教育模式,通过CHIPS培养模式不仅提高了药理学教师的教学业务水平,更是培养学生在药理学课程学习过程中的自学能力、科研思维和创新能力。

耐甲氧西林金黄色葡萄球菌CHIPS基因的克隆、序列分析及原核表达

目的对耐甲氧西林金黄色葡萄球菌(MRSA)趋化抑制蛋白(CHIPS)进行扩增、克隆、序列分析、原核表达及纯化,为后续的疫苗研究奠定基础。方法根据GenBank中趋化抑制蛋白(CHIPS)的序列,设计一对特异性引物,以耐甲氧西林金黄色葡萄球菌DNA为模板PCR扩增CHIPS基因,纯化DNA进行EcoRI、XhoI双酶切鉴定及测序鉴定,并将CHIPS亚克隆入表达载体PET-28α,转化感受态大肠杆菌BL21,对质粒进行双酶切鉴定及基因序列分析,用IPTG诱导表达重组蛋白,His标签单克隆抗体进行免疫印迹验证重组蛋白的表达。结果以金黄色葡萄球菌临床儿童分离株基因组为模板,成功扩增CHIPS基因,基因大小为450bp;重组PET-28a(+)-CHIPS双酶切鉴定可见目的片段,测序结果显示CHIPS在正确读框中,序列比对分析显示其与相关报道核苷酸序列一致性达99.98%。经IPTG诱导后,pET-28a(+)-CHIPS/BL21在相应分子量(17kDa)可见融合蛋白在上清表达,免疫印迹检测到目的蛋白。结论成功从儿童分离株MRSA中构建了CHIPS的原核表达系统,并成功在大肠杆菌BL21中融合表达,为后续的疫苗研究奠定基础。

CHIPS教学理念在药理学教学中的探索和实践

为了加强高等医药院校人才素质的培养,通过CHIPS教学理念在药理学教学中的探索和实践,促进药理学教学理念的更新和教学质量的提高,从而培养具有创新精神、较强的动手能力和主动性的富有潜力的、服务于社会的药学人才。

Microstructure evolution of hot pressed AZ91D alloy chips reheated to semi-solid state

AZ91D magnesium alloy chips, which were directly collected on the spot of machining process, were recycled to prepare billet via hot pressing for semi-solid processing. The semi-solid microstructure evolution of the billet during reheating was investigated. The results indicate that there are three stages during reheating to semi-solid state: the dissolution of Mg17Al12 and diffusion of Al into α-Mg matrix, the melting of the region with high content of solute and formation of isolated solid particles, and spheroidization and growth of solid particles. Meanwhile, a number of entrapped liquid droplets form within solid particles. In addition, the number and size of entrapped liquid droplets rely on the holding time in the semi-solid temperature range. With increasing isothermal holding time, the solid fraction remains unchanged when the solid-liquid system reaches the dynamic equilibrium at last, while the solid particles become more globular and the average size of solid particles increases owing to the decreasing of interfacial energy and the effect of interfacial tension.

世界性的资金调拨系统——CHIPS

第二次世界大战后,商品生产的规模和交换方式都发生了很大的变化。科学技术的发展,促使劳动生产率迅速提高和国际贸易急速发展,从而使商品流动和货币流动急速加大。通过电信和手工处理纸基票证这种传统的转帐方式,已经不能适应时代发展的要求。为适应国际贸易急速发展的需要,从60年代末开始,国际银行界纷纷研究建立各种国际资金调拨系统。在诸多国际资金调拨系统中,最重要的是SWIFT系统和CHIPS系统。SWIFT系统主要提供通信服务,为其成员金融机构传送各种标准的国际资金调拨信息。

Study on Ignition Proof AZ91D Magnesium Alloy Chips with Cerium Addition

The effect of Ce on ignition point of AZ91D magnesium alloy chips was studied. For the AZ91D and the AZ91D-xCe magnesium alloys, changing the sizes of the chips in the range of 58 - 270 μm has a limited influence on ignition point, however, the shift of the content of Ce has much effect on ignition point. Increasing the Ce content, x from 0.15 to 0.25, the ignition point increases with increasing of Ce; however, x from 0.25 to 0.45, the ignition point decreases with increasing of Ce. By the addition of Ce of 0.25 %. the ignition point is raised by 43℃.

Measurement of 3db Bandwidth of Laser Diode Chips

An accurate technique for measuring the frequency response of semiconductor laser diode chips is proposed and experimentally demonstrated.The effects of test jig parasites can be completely removed in the measurement by a new calibration method.In theory,the measuring range of the measurement system is only determined by the measuring range of the instruments network analyzer and photo detector.Diodes' bandwidth of 7 5GHz and 10GHz is measured.The results reveal that the method is feasible and comparing with other method,it is more precise and easier to use.

Recycling of AZ91 Mg alloy through consolidation of machined chips by extrusion and ECAP

AZ91 Mg alloy recycled by a solid state process and equal channel angular pressing(ECAP)exhibited a superior strength. The mechanical properties of AZ91 Mg alloy recycled from machined chips by extrusion at 623 K and ECAP at 573 K and 623 K were compared with those of the reference alloy which was produced from an as-received AZ91 Mg alloy block under the same conditions as the recycled alloy.The recycled specimens show a higher strength at room temperature than the reference alloy.The improvement of the tensile properties is attributed not only to the small grain size,but also to the dispersed oxide contaminants.

Comparison of a commercial powder and a powder produced from Ti–6Al–4V chips and their effects on compacts sintered by the sinter-HIP method

The present paper is related to the conversion of Ti–6Al–4V chips into powder and investigates the usability of the produced powder in powder metallurgy applications. In this regard, a disc-milling process was applied to Ti–6Al–4V chips and the obtained powder was subsequently compacted. The compacted samples were sintered by the sinter hot isostatic pressing (sinter-HIP) method at 1200°C under high vacuum, their mechanical properties and microstructure were investigated and compared with those of commercial powder compacts subjected to the same preparation processes. The results showed that the produced powder exhibits greater flowability and higher apparent density than the commercial powder. However, the sintered products prepared from the commercial powder exhibited a higher relative density, lower porosity, and, as a result, greater flexural strength compared with the sintered compacts prepared from the produced powder. In addition, transgranular fracture was greater in the sintered products of the commercial powder. The microstructural studies revealed that the sintered products made from both the commercial and the produced powders consisted of α- and β-phase but contained more α-phase. All of the examined properties were found to be substantially affected by the particle size of the powders.

Microstructure and tensile properties of magnesium nanocomposites fabricated using magnesium chips and carbon black

In this study,carbon black(0,0.01,0.03 and 0.08 wt%)and AZ31(Mg-3Al-lZn)magnesium chips were used to fabricate carbon black-reinforced magnesium matrix composites with extrusion or a combination of extrusion and high-ratio differential speed rolling.After hot pressing at 693 K and extrusion at 623 K with an extrusion ratio of 22,the magnesium chips coated with carbon black were soundly bonded into a bulk composite material.The grain sizes of the extruded materials were similar with a size of 48.2-51.5|im despite the difference in the amount of carbon black.The yield strength and ultimate tensile strength increased from 177 to 191 MPa and from 240 to 265 MPa,respectively,as a result of the addition of 0.01%carbon black;however,a further increase in the strength was marginal with additional carbon black.The same trend was observed in the strain hardening behavior.The tensile elongation increased by to the addition of 0.01%carbon black(from 15.8%to 17.4%)due to the increased work hardening effect,but decreased with additional carbon black due to its agglomeration and poor dispersion at higher concentration.After high-ratio differential speed rolling(HRDSR)on the extruded materials and subsequent annealing,the AZ31 and AZ31 composites had a similar fine grain size of 16.3-17.9 p.m.The annealed HRDSR composites showed the best mechanical properties at a higher content of carbon black(0.03%)compared to that(0.01%)for the extruded composites.This resulted from the enhanced dispersion effect of the carbon black due to the high shear flow induced during the HRDSR process.The extruded composites exhibited the three distinct hardening stages(stage II,stage III and stage IV),while the annealed HRDSR composites mainly displayed the stage III hardening.The addition of carbon black increased the strain hardening rate at all the strain hardening stages in both of the extruded and annealed HRDSR materials.At the initial hardening stage,the strain hardening rates of the extruded composites were higher than those of the annealed HRDSR composites,but this became reversed at the later stage of hardening.Possible explanations for this observation were discussed.The strength analysis suggests that dislocation-carbon black interaction by Orowan strengthening and dislocation generation due to a difference in thermal expansion between matrix and carbon black are the major strengthening mechanisms.

Exploring Genome-wide DNA Methylation Profiles Altered in Kashin-Beck Disease Using Infinium Human Methylation 450 Bead Chips

To understand how differentially methylated genes（DMGs）might affect the pathogenesis of Kashin-Beck disease（KBD）.Genome-wide methylation profiling of whole blood from 12matched KBD and controls pairs was performed using a high-resolution Infinium 450 K methylation array.In total,97 CpG sites were differentially

Lathe process of AZ91D magnesium alloy chips used in semi-solid thixomolding

Based on the mechanism of chip breaking and the principle of semi-solid thixomolding, the lathe process of AZ91D magnesium alloys chips used in semi-solid thixotropic injection molding process was studied. With three kinds of turning tools, such as 31303C5, 31003C and 31303C, different chips were gotten. And by one tool with different lathe parameters, different chips were gotten. The results show that, under the needed condition of the thixotropic injection molding machine, the ideal chips are gotten and the size of magnesium alloy chips must be about 35mm, and the turning tool is chosen, whose chip breaker groove is narrower and the depth of cutting is more than 3mm as well as the amount of feed is larger than 0.3mm. The deformation occurs on the microstructure of the chips, and the residual stress is important to the later microstructure of semi-solid state in injection molding.

Design of Multi-mode Mobile Terminal Chips

Based on the analysis of B3G evolution, the base-band processing chips for mobile terminals are introduced. Key technologies for multi-mode mobile terminal base-band chips are discussed. Terminal technologies are thought to be the key of B3G, and terminal base-band chips are regarded as the core of terminal technologies. Therefore, a unified wireless development platform is required for the R&D of multi-mode mobile terminal base-band processing chips.

Hazardous effects of fried potato chips on the development of retina in albino rats

Objective:To evaluate the hazardous effects of fried potato chips upon the retina of two developmental stages of the albino rats aged 7 and 14 days from parturition.Methods:Pregnant rats were arranged into two groups:control pregnant rats and consequently their delivered newborns until reaching 7 and 14 days old from parturition and fried potato chips group in which pregnant rats at the 6th day of gestation maintained on diet formed of fried potato chips supplied from the market mixed with standard diet at a concentration of 50%per each till 7 and 14 postpartum.Three fold integrated approaches were adopted,namely,histological,ultrastructural and proteomic analysis.Results:Histological examination of the retina of the experimental offsprings revealed many histopathological changes,including massive degeneration,vacuolization and cell loss in the ganglion cell layer,as well as general reduction in retinal size.At the ultrastructural level,the retina of experimental offsprings exhibited number of deformities,including ill differentiated and degenerated nuclear layer,malformed and vacuolated pigment epithelium with vesiculated and fragmented rough endoplasmic reticulum,degenerated outer segment of photoreceptors,as well as swollen choriocapillaris and loss of neuronal cells.Proteomic analysis of retina of the two experimental developmental stages showed variations in the expressed proteins as a result of intoxication which illustrated the adverse toxic effects of fried potato chips upon the retina.Conclusions:It can be concluded that the effect of fried potato chips on the development of retina in rats may be due to the presence of acrylamide or its metabolite.

Microstructural evolution during reheating of A356 machining chips at semisolid state

The microstructural evolution of A356 machining chips in the semisolid state was studied at different temperatures and holding times. The results showed that the elongated α-Al grains first recrystallized in the semisolid state and then became globular with a high shape factor(SF). Both the temperature and the holding time clearly affected the grain size and SF. When the heating temperature or holding time was increased, the grain size and SF gradually increased and finally became stable. Moreover, the Vickers hardness of primary α-Al grains gradually decreased with increasing heating temperature. The optimal slurry for semisolid processing, with a good combination of grain size and SF, was obtained when the chips were held at 600℃ for 15 min. The semisolid slurry of A356 chips exhibited a lower coarsening rate of α-Al grains than those produced by most of the conventional semisolid processes. The coarsening coefficient was determined to be 436 μm^3·s^(-1) on the basis of the linear Lifshitz–Slyozov–Wagner(LSW) relationship.

Mechanical properties and microstructure of composites produced by recycling metal chips

In this study, the processing and mechanical properties of porous metal matrix composites(MMCs) composed of spheroidal cast iron chips(GGG40) and bronze chips(CuSn10) and formed by hot isostatic pressing were investigated. Bronze chips(CuSn10) were used as a matrix component, and spheroidal cast iron(GGG40) chips were used as a reinforcement component. The MMCs were produced with different CuSn10 contents(90 wt%, 80 wt%, 70 wt%, and 60 wt%). The hot isostatic pressing process was performed under three different pressures and temperatures. The produced MMCs were characterized using density tests, Brinell hardness tests, and compression tests. In addition, the consolidation mechanism was investigated by X-ray diffraction(XRD) analysis and scanning electron microscopy. The test results were compared with those for bulk CuSn10 and bulk GGG40. Mechanical tests results revealed that the metallic chips can be recycled by using hot pressing and that the mechanical properties of the produced MMCs were similar to those of bulk CuSn10. XRD and microscopy studies showed that no intermetallic compounds formed between the metallic chips. The results showed that the CuSn10 and GGG40 chips were consolidated by mechanical interlocking.