The purpose is to study the vertical linear uncertainty of ultrasonic flaw detectors. Firstly, introduce the specific instrument models and technical parameters, analyze the basis and methods for evaluating the vertical linear uncertainty of ultrasonic flaw detectors, and conduct uncertainty evaluation through modeling. Finally, issue a vertical linear uncertainty report and propose the key points for calibrating the ultrasonic flaw detector calibration device. Intended to provide reference for ultrasonic detection personnel, master the exploration skills of vertical linear uncertainty of ultrasonic flaw detectors, truly optimize the quality and performance of ultrasonic flaw detectors, and truly play its functional role.

Objective This article mainly introduces three methods for measuring pitting depth: metallographic method, micrometer method and microscopy method, and discusses their differences in different pitting conditions and their influence on the measurement results. Methods Pitting pits on the surface of carbon steel and stainless steel were respectively measured by using these three measuring methods. and the measured results were analyzed and discussed. Results By comparing the measurement results, we can see that the metallographic method is more accurate, but it is destructive. The micrometer method is only suitable for wide and shallow pitting pits. The microscope method is not only suitable for wide and shallow pitting pits, but also for the small pit bottom. Conclusion (1) For wide and shallow pitting pits, metallographic method, micrometer method and microscopic method are applicable and the results are consistent; (2) For the small pitting pit at the bottom, metallography and microscopy are more suitable and the results are consistent; (3) When the corrosion depth is measured by metallographic, microscope and micrometer methods, the thickness reduction caused by uniform corrosion should be taken into account and the results should be corrected, especially in the case of more obvious uniform corrosion.

The high and low temperature test chamber can provide thecorresponding high and low temperature environment for instruments andmaterials, and its temperature field performance and measurementuncertainty are important indicators that affect the measurement resultsof the temperature test chamber. Through the uncertainty evaluation andinfluence analysis of temperature deviation calibration results, themeasurement performance of high and low temperature test chamber, errorsources and methods to reduce the influence of error are furtherunderstood. According to the calibration method specified in GB/T10592-2023 Technical Conditions for High and Low Temperature TestChamber, select the temperature sensor that meets the measurementrequirements and calibrate the temperature deviation of the high and lowtemperature test chamber. The calibration confirms that the temperaturefield performance of the high and low temperature test chamber meets thetolerance requirement of temperature deviation $\pm {2}^{\circ }\mathrm{C}$ , and themeasurement uncertainty meets the technical index requirement of $1/3$ maximum allowable error. Thetemperature field performance of the high-low test chamber is good, andthe short-branch A-class platinum thermal resistance selected by themeasurement standard meets the calibration requirements and has goodstability.

Objective To understand the sanitary condition of secondarywater supply in jinan railway area and provide scientific basis forrailway departments to improve secondary water supply. Methods Accordingto ( Standard test method for drinking water $\}$ , we sampled and tested the waterquality. On the basis of $《$ Hygienic specification for facilities of secondary water supply》, weanalyzed the data about engineering acceptance and daily detection waterquality. Results Daily detection of secondary water supply qualifiedrate was ${82.69}\%$ , higher thanengineering acceptance of secondary water supply qualified rate ${65.77}\%\left({P <{0.05}}\right)$ .Acoording to the daily detection qualified rate analysis of secondarywater supply, the qualified rate of water supply from living area,passenger station, well of the train track and train water tank wasdecreased successively. The difference of the qualification rate amongthe sampling locations is statistically significant $\left({P <{0.05}}\right)$ ; Thequalified rate in each month is all above ${74}\%$ . The qualified rate in March,April, June and September is below 80%.Soil microbial indicators anddisinfectant indicators qualified rate trend consistent with allindicators qualified rate trend. The qualified rate of ex-factory waterwas ${90.54}\%$ , which was higherthan ${81.19}\%$ of peripheral water $\left({P <{0.05}}\right)$ . Theunqualified soil microbial indicators and disinfectant indicators arethe main factors causing the unqualified secondary water supply. Conclusion The qualified rate of secondary water supply in jinan railwayarea is higher than other water supply types, but there are hiddendangers in the health situation. The supervision of secondary watersupply should have further strengthen.

There are problems with insufficient resource utilization, traditional experimental teaching content, and limited scientific research in experimental teaching laboratories and scientific research laboratories in universities. Opening up laboratories is the main way to improve the utilization of laboratory resources. Opening up laboratories is beneficial for enhancing students' innovative thinking and research abilities, promoting scientific research achievements among teachers and students, improving the utilization of laboratory resources, solving laboratory management problems, and promoting the implementation of industry university research work. This paper takes experimental teaching laboratories and scientific research laboratories in universities as research objects, elaborates on the problems of laboratory opening, analyzes the measures that should be taken for laboratory opening, and proposes the mechanism for opening experimental teaching laboratories and scientific research laboratories in universities.

Objective In chemical analysis, the focus used to be on theprecision and accuracy of detection results. However, many testingactivities currently require establishing the credibility of theresults. Especially by measuring the credibility of the results to provetheir suitability, this generally includes the degree to which oneoutcome is expected to match other outcomes, which is also thesignificance of exploring uncertainty. Methods According to theCNAS-GL06 Guidelines for Evaluation of Uncertainty in Chemical Analysis,this article detected the content of phosphate ions in a certainindustrial wastewater and studied and analyzed the components thataffect measurement uncertainty during the experimental process. ResultsThrough calculation, it can be concluded that when the result ofphosphate ion is ${3.00}\mathrm{{mg}}/\mathrm{L}$ , theconfidence interval is ${2.86}-{3.14}\mathrm{{mg}}/\mathrm{L}\left({\mathrm{k}= 2}\right)$ . Conclusion The main factor affecting its measurement uncertainty is theuncertainty introduced by the calibration curve fitting. In order tomake the detection results more scientific and accurate, it is necessaryto pay attention to the maintenance and upkeep of the ion chromatographin daily work, minimize the background noise of the instrument, andimprove the sensitivity and accuracy of the instrument.

Microbial testing is of high importance in grassroots disease control centers. Effective microbial testing can ensure the disease prevention ability of grassroots disease control centers. In order to better implement disease control work, grassroots disease control centers attach great importance to the completion of microbial testing work. However, based on the completion of microbiological testing in some grassroots disease control centers in certain regions, there are still some omissions that have not been rationalized in the implementation process, which has had a certain impact on the application value of microbiological testing. Based on the consideration of the importance of microbiological testing in grassroots disease control centers, this article explores common problems and countermeasures in microbiological testing in grassroots disease control centers, in order to promote the improvement of microbiological testing accuracy. Targeted comprehensive analysis work is carried out from multiple aspects such as grassroots disease control center staff, equipment and instruments, and work environment, in order to achieve precise control and effective handling of related issues.

In response to the issues of inconsistent safety risk management standards, specialized level of safety management, and differentiated control in university laboratories, based on the concept of "full staff education, full process education, and all-round education", this paper proposes the use of information technology to promote laboratory safety classification and grading management measures. Multiple methods such as quantitative, qualitative, or comprehensive evaluation are used to evaluate the degree of risk that may be caused by hazards. Based on the practice of integrating the "Three Comprehensive Education" into the laboratory culture education system of our university, explore the information management mode of safety classification and classification in university laboratories.

Safety is the basic guarantee for university laboratories to carry out teaching and research. The dual prevention mechanism with risk classification control and hidden danger investigation and management as the core can effectively curb the occurrence of laboratory safety accidents. This paper describes the four stages of building a dual prevention mechanism, and uses the operating condition risk assessment method (LEC) to evaluate and grade laboratory risks, moving the threshold of laboratory risk management and control to the risk point classification management and control, and building a solid laboratory safety defense line.

In the process of investigating ecological and environmental pollution cases, problems such as difficulty in identifying the attributes of unknown solid waste, complex identification processes, and slow identification time have always affected the efficiency of case investigation. Through personnel interviews, on-site investigations, and initial screening of on-site rapid detection equipment, comprehensive analysis is conducted to determine the detection indicators for the hazardous characteristics of unknown solid volatile organic compounds. The leaching toxicity and toxic substance content of volatile organic compounds are analyzed to identify unknown solid waste as hazardous waste. Accurate identification of hazardous characteristics greatly saves emergency inspection time and provides scientific basis for emergency disposal of unknown solid waste, improves case handling efficiency, and has guiding significance for similar ecological environment damage cases. At the same time, this article also studies the toxicity detection method of volatile organic compounds in solid waste.