炭黑分散度检测标准GB/T 18251应用过程中遇到的问题浅析

主要对GB/T 18251—2019《聚烯烃管材、管件和混合料中颜料或炭黑分散度的测定》标准中给出的炭黑分散度检测过程中试样厚度范围、厚度测量方法及切片法中试样形状、试样幅宽、试样制备过程中遇到的问题做了讨论研究。试样厚度是制备试样的一个重要参数,标准中未给出具体测量方法,应予以补充,建议采用显微镜测量法。标准中给出的炭黑分散度试样厚度范围（20±10）μm不合适,实际检测过程中发现能用于试验的试样厚度小于10μm。标准中未给出切片法制备试样的形状和幅宽,建议使用正方形试样,幅宽4 mm,切片过程中可能会遇到无法切到指定厚度范围的试样,可以采用低温冷冻后再切样的办法解决。     

直流辉光放电质谱法测定氧化铝中的杂质元素

为了探索采用直流辉光放电质谱法(dc-GDMS)测定非导体样品中的杂质含量,建立了dc-GDMS法测定α-Al₂O₃粉末中杂质元素的方法。以Cu粉作为导电介质,与α-Al₂O₃粉末混合均匀,压片,考察辉光放电条件（放电电流、放电气体流量、离子源温度）和压片条件（两种粉末的混合比例、压片机压力等因素）对放电稳定性和灵敏度的影响,同时优化了实验条件。尝试将Al、O、Cu的总信号归一化进行计算,并用差减法计算了Al₂O₃粉末中的杂质含量。方法精密度在54%以内,元素检出限为0.005~0.57 μg/g。该方法的测定结果与直流电弧发射光谱法的测定结果基本吻合。     

认识全色密度计在射线检测中的作用

由国家计量部门相关政策变更所引发的一系列问题，给射线检测结果带来诸多变数，也直接影响到检测的质量。启用兰片基标准密度片奖有助于广大密度计用户及时发现问起，并找到解决问题的好方法。     

Channeling Agent and Drug Release from a Central Core Matrix Tablet

A new oral dosage form for controlled and complete release of drug after a predetermined lag time is described. The system, designed to exploit the relatively constant small intestine transit time, consists of a drug-containing core coated with a polymeric matrix formed by a channeling agent (NaCl, mannitol, and Emdex) and an inert polymer (Eudragit RS100). The lag time was found to be dependent on type and particle size of the channeling substances used. Also, rheological properties of the binary mixtures (channeling substance–polymer) can affect the lag time periods. On the other hand, the release kinetics were found to be influenced significantly by excipient type and particle size. Results obtained from in vitro dissolution testing demonstrated that this device potentially could be used to deliver drugs orally for up to once-a-day dosing at controllable rates.     

SeDeM expert system a new innovator tool to develop pharmaceutical forms

Context: The SeDeM expert system is based on the experimental study and quantitative determination of the characterization parameters of powdered substances, the aim being to determine whether a substance is suitable for producing tablets by means of direct compression (DC) technology, thereby reducing the lead time for pre-formulation studies. Additionally, this expert system also provides formulations with a minimum number of excipients.

Objective: We used this system to analyze suitable formulas for the production of orodispersible ibuprofen tablets.

Method: Twenty-one disintegrants and ibuprophen were characterized using SeDeM methodology.

Results: The results indicated that production of ibuprofen tablets by DC would require improvements in the dimension and compressibility factors of the active pharmaceutical ingredient. The expert system analysis provided the specific percentage of disintegrant needed to blend with ibuprofen and a standardized formula of lubricants in order to obtain a powder mix that would successfully produce tablets by DC. The eight formulas proposed by SeDeM were produced and tested in the laboratory.

Conclusion: All eight formulas successfully produced tablets by DC, but only four of them could be considered suitable for use as an orodispersible tablet and accomplishes all the pharmaceutical quality parameters. So, in fact, the use of the SeDeM system reduced the time of medicine’s development and therefore the cost of the activity.     

Quality perception when streaming video on tablet devices

The proposed work aims at analyzing the quality perceived by the user when streaming video on tablet devices. The contributions of this paper are: (i) to analyze the results of subjective quality assessments to determine which Quality of Service (QoS) parameters mainly affect the users’ Quality of Experience (QoE) in video streaming over tablet devices; (ii) to define a parametric quality model useful in system control and optimization for the considered scenarios; (iii) to compare the performance of the proposed model with subjective quality results obtained in alternative state-of-the-art studies and investigate whether other models could be applied to our case and vice versa.     

Parametric study of surfactant effect on mechanical and dissolution properties of detergent tablets

The aim of this study is to investigate the functional characteristics (mechanical strength and disintegration time) of effervescent detergent tablets containing chlorine provider in the presence of surfactant. A preliminary study high-lighted that the presence of 2% of sodium dodecyl sulfate (SDS) was not favorable to the tablet mechanical properties, inducing a lower “bonding ability,” whereas the disintegration time increased, compared with the reference tablets without surfactant. The linear relationship between the disintegration time and the end-dissolution time led us to consider just the disintegration time to express the behavior of the tablets in water. A parametric study has been completed to assess the influence of the mixing method, the nature, the hydrophilic-lipophilic balance, the granulometry, and the concentration of the surfactant on the tablet properties. In all cases, surfactant presented adverse effects on the mechanical properties and had a retarding effect on disintegration time, but neither solubility, hydrophilic-lipophilic balance, interfacial properties, nor ionic character could be clearly involved to explain surfactant contribution. Furthermore, tablet dissolution could not be correlated to surfactant available surface, as evidenced by granulometry comparison on one side and concentration impact on the other side (a similar effect was observed from 1 to 15%). On the contrary, mechanical properties were damaged as much as the area developed by surfactant particles increased. On the basis of this work, it has been concluded that SDS interacts with the other compounds of the formula by creating weak interparticle bonds and limiting water uptake responsible for disintegration.     

Press chamber coating as external lubrication for high speed rotary presses: lubricant spray rate optimization

Lubrication of the tooling (punches and dies) is necessary to produce tablets. The most commonly used lubricant is magnesium stearate. Adding and blending magnesium stearate to the tablet mass often has negative effects on the properties of the compressed tablets (e.g., decreasing the tensile strength of the tablet). To avoid these negative effects, external lubrication systems were developed. This study investigated the functionality and the influence of a new press chamber coating system called the PKB II. The major difference between the PKB II and previous systems is its ability to spray a mixture of powdered magnesium stearate and air directly onto the punches and dies which was determined to allow the running of the rotor at higher speeds. The data showed a clear correlation between the spray rate of the lubricant and the concentration of the magnesium stearate per tablet. The PKB II was designed to allow for adjustments, in order to optimize the spray rate, by using the ejection force. The concentration of magnesium stearate was reduced to approximately 0.04% per tablet, using the PKB II. Additionally, the most common negative effects, such as the decrease in tablet tensile strength, were avoided by using this system.     

利用NRF24E1实现带语音传输的无线手写板

在无线电脑遥控器的基础上,利用NRF24E1设计了带语音传输和带手写板传输的无线遥控系统。针对按键、语音和手写板3种不同数据的特点,对数据进行复用,制定了数据传输协议;为了保证数据的实时传输,采用ISM频段进行数据的传输;不同的系统采用频分复用,可以实现多套系统的无干扰传输。给出了系统设计框图、硬件原理图和软件流程,并对系统的功能进行了测试。研究表明该系统能够同时实现无线智能键盘、无线手写板和无线语音的功能。     

无糖软儿梨含片生产工艺研究

对具有营养保健功能的无糖软儿梨含片的加工工艺进行了初步研究,结果表明,采用软儿梨浓缩膏6%、甜味剂75%(山梨糖醇:木糖醇:结晶麦芽糖醇为3∶0.5∶0.5)、低聚异麦芽糖18.5%、柠檬酸0.5%等基本原料配比,以50%乙醇溶液作润湿剂,0.5%硬脂酸镁作润滑剂,经混合、造粒、干燥、压片等工艺,制成了低糖、低热量、具有保健功能的无糖软儿梨含片.