87results about How to "Improve experiment safety" patented technology

The invention relates to a radioactive liquid waste treatment device comprising a feeding device, a volume reducer of radioactive wastes, a tail gas and residual liquid treatment device and a conveyer. The feeding device, the tail gas and residual liquid treatment device and the conveyer are respectively connected with the volume reducer; the feeding device, the tail gas and residual liquid treatment device, the conveyer and the volume reducer are integrally arranged under a vacuum environment; the volume reducer comprises a macroscopic dehydration volume-reduction unit for macroscopically dehydrating and reducing volume of the radioactive liquid wastes and a heating-drying volume-reduction unit, and the heating-drying volume-reduction unit and the macroscopic dehydration volume-reductionunit for breaking the organization structure of the radioactive wastes are connected by a pipeline to form a seal system. A movable radioactive liquid waste treatment device disclosed by the invention has the advantages of little environment pollution, safe and reliable treatment process and reduced storage space, and reaches the state standard of effluent discharge.

The invention discloses an experiment device and an experiment method for simulating blowout depressurization of a fourth-stage automatic depressurization system for a reactor. The experiment device comprises a pressure container, a T-shaped tube experiment section, a steam-water separator, a capturing water tank, a heating water tank, a second filter and a high-temperature pump, wherein a horizontal heat tube section of the pressure container is connected with a horizontal branch tube of the T-shaped tube experiment section; a vertical branch tube of the T-shaped tube experiment section is connected with the capturing water tank through the steam-water separator; the capturing water tank is connected with the heating water tank through a pipeline; the heating water tank is connected with a water inlet of the pressure container through the filter, the high-temperature pump and a preheating section. The experiment device can execute two experiments for converting air into water and converting steam into water; the air-to-water experiment can be used for executing mechanism-based experiments such as entrainment start and a steady-state entrainment rate, and the steam-to-water experiment can be used for executing the mechanism-based experiments and also executing a blowout pressure release simulation experiment of the ADS-4 (fourth-stage automatic depressurization system). The experiment device has the advantages of high safety, high experiment data precision, easiness in mounting and maintenance and the like.

The invention discloses a nuclear reactor pressure regulator safety valve water seal test system and method. A circuit can carry out low-pressure and medium-pressure hydraulic water seal experiments under vacuum, air and multi-component non-condensable gas, and reveals the water seal process and the hydraulic water seal mechanism phenomenon of the hydraulic water seal structure. The circuit mainlyincludes a deionized water system, a heating water tank, a hot water pump, a pressure vessel, a vacuum pump, a non-condensable gas, an exhaust pressure relief port, a water seal experimental section,and a control and acquisition system. The experimental pressure range is from 0.1 to 1.0 MPa and the temperature range is 0 to 180 degrees centigrade. The experimental circuit of the present invention can realize the visualization of the experimental phenomenon of the water seal structure. The circuit pressure vessel is designed in an integrated manner and has multiple sensing devices. The systemand method have the advantages of high safety, high precision of experimental data, and easy installation and maintenance.

The invention discloses a temperature controllable method and system for testing a burning behavior of a metal material. The method comprises the following steps: (1) making a sample; (2) adding an igniter; (3) mounting the sample and an anti-splashing device; (4) vacuumizing, so that the vacuum degree is 0MPa-1MPa; (5) heating, so that the temperature reaches 100-1,000 DEG C; (6) charging gas until the required temperature is 1MPa-80MPa; (7) adjusting the pressure; (8) igniting the igniter and the sample; (9) recording a whole burning process with a camera, recording the change of temperature of the burned sampled with a temperature measurement device and recording the change of internal pressure of the system with a pressure measurement device; (10) vacuumizing; (11) taking out the sample. The system comprises a sample clip, wherein the anti-flashing device is arranged at the periphery of the sample clip; an igniting device is arranged at the bottom of the sample clip; the sample clip is located in an environment of a heating device and a gas circulation device; the gas circulation device is connected with an external air charging device and a cooling device.

The invention discloses a pressure vessel and a method for simulating upper chamber droplet entrainment of nuclear reactor. The pressure vessel is mainly composed of a water inlet, a gas inlet, a heating area, an experimental area and an air water outlet. The pressure vessel can carry out experiments in two working media, air-water and steam-water, can use heating rods to simulate core decay heat and realize physical simulation of the upper chamber entrainment phenomenon; and reactor internals and core upper plate contained in the pressure vessel can realize real reflection of simulation of upper chamber entrainment deposition phenomenon; in addition, the experimental device has the advantages of experimental process visualization, high safety and easiness for installation and maintenance, etc.

The invention provides a food lipid extraction method and a detection method of lipid in food. The food lipid extraction method comprises the following steps of: mixing and centrifuging a food sample with ultrapure water, methanol and dichloromethane for multiple times, wherein the lower layer of an organic phase obtained after multiple times of centrifugation is lipid. A small amount of samples is utilized, and extracts of different lipids through one-time treatment by using a safer lipid extraction reagent are obtained, and are subjected to qualitative and quantitative detection simultaneously or respectively. The sample consumption is reduced, the safety is improved, the consumables in the sample pretreatment and detection process are saved, the cost is reduced, and the efficiency is improved.

The invention discloses a working condition simulation test circuit and method for a cascaded converter sub-module. The circuit comprises a current generator which is used for generating a current needed by a to-be-tested sub-module; the to-be-tested sub-module which is used for receiving a current signal and outputting a capacitor voltage signal; a voltage controller which is used for receiving the capacitor voltage signal and generating a voltage regulation signal, so that the capacitor voltage of the to-be-tested sub-module is consistent with a reference voltage; a current controller whichis used for receiving the current signal and the voltage regulation signal and generating a control signal of the current generator to control the running state of the current generator; an auxiliarybridge arm which is switched on when the to-be-tested sub-module operates in a cut-off state and matches the current generator to carry out auxiliary adjustment on the output current of the current generator; an auxiliary bridge arm controller which is used for controlling the auxiliary bridge arm; and a converter system model which is used for controlling the to-be-tested sub-module, the currentcontroller and the voltage controller. According to the invention, the test cost is reduced, and the safety is improved.

The invention discloses a full-automatic nucleic acid extraction, amplification and detection instrument, which comprises a working box body and an operation display screen, wherein a machine core device is arranged in the working box body, is electrically connected with the operation display screen and comprises a nucleic acid extraction, amplification and detection device, a thermal cycling device, an adjustable light supplement lamp device and an optical detection device; and the optical detection device is installed in the machine core device and is positioned above the nucleic acid extraction, amplification and detection device. A start button on the operation display screen is pressed down, and the nucleic acid extraction, amplification and detection device carries out nucleic acid extraction, amplification and detection; after detection is finished, the adjustable light supplement lamp device can be automatically on so as to assist the optical detection device in photographing and detecting the nucleic acid extraction, amplification and detection device; through the operation display screen, a sample detection situation can be displayed; a whole process can be automaticallycarried out and does not need people to intervene and participate, an automation degree is high, errors and cross contamination caused by manual detection can be avoided, and efficiency is greatly improved.

The invention discloses a magnetic bead-based DNA extraction method, a lysate and a kit. The lysate is characterized in that a buffer solution with a sodium ion content of greater than or equal to 140mmol and a pH value of 7 to 9 contains a chaotropic agent with a concentration of 3 mol / L to 6 mol / L, 5 mmol to 20 mmol of a metal chelating agent and 5% to 15% by mass of polyethylene glycol. The extraction method comprises the following steps: (1) acquiring a cleavage reaction system; (2) treating the cleavage reaction system; (3) adding nanometer magnetic beads; (4) acquiring magnetic beads binding to DNAs; (5) carrying out washing and then performing DNA elution. The kit comprises the lysate, a proteinase K solution, a magnetic bead dispersion liquid, a first washing solution, a second washing solution, a third washing solution and an eluent. Reagents used in the invention are non-toxic, so experimental safety is improved; and only one-step liquid adding operation is required, so labor cost is greatly reduced.

The invention provides a constant-speed blurred image construction method and device based on splicing of two frames of static images, belonging to an image movement analyzing part in the common image data processing or generating field. The method comprises the following steps of: deducing a blurred distance of a target under an actual condition according to the target in an actual scene, an optical system and parameters of an image sensor, and inversely deducing to an image space to obtain a distance of positions of the target in two spaces; and carrying out two times of imaging on a substituted target of the positions of the two spaces and constructing a constant-speed blurred image according to image information. The substituted target in the device comprises two parts including a static background and a movable target; and the movable target can do two-dimensional movement in a view field range of a substituted optical system in a direction which is vertical to an optical axis of the device. The method and the device can utilize a room-temperature visible light target to equivalently replace a high-temperature target; a low-speed movement is matched with two times of imaging to equivalently replace a high-speed movement, so that the experiment difficulty is reduced and the experiment safety is improved; and a plurality of groups of experiment data are easy to obtain and the experiment cost is greatly reduced.

The invention discloses a high-grade biosafety protection type air propagation experimental device for pathogens of medium and small animals. The high-grade biosafety protection type air propagation experimental device can be used for carrying out a droplet propagation experiment on the medium and small animals such as rats, mice, martens and rabbits. The high-grade biosafety protection type air propagation experimental device comprises a biosafety cabinet, wherein the biosafety cabinet comprises an exposure cavity for accommodating healthy animals and bacteria-carrying animals; a sealed experimental box is arranged in the exposure cavity; the healthy animals and the bacteria-carrying animals are placed in the experimental box; the biosafety cabinet is provided with an air supply filteringdevice and an air exhaust filtering device; the air supply filtering device is used for supplying air into the exposure cavity; the air exhaust filtering device is used for purifying air in the exposure cavity and exhausting the air; the experimental box comprises an air inlet and an air outlet; the air inlet communicates with the air supply filtering device; and the air outlet communicates withthe air exhaust filtering device. According to the technical key points, the experimental animals are placed in the experimental box and the propagation experiment is not directly carried out in the biosafety cabinet, so that the pollutant diffusion range is reduced and the experiment is safer; and the section of the droplet propagation experimental box is small and an accurate experimental resultis easy to obtain.

The invention provides a working condition simulation test system for a cascade converter sub-module. The working condition simulation test system comprises a current generator used for outputting a current, the to-be-tested sub-module used for receiving the current generated by the current generator and outputting a capacitor voltage signal, an electric impedance network used for controlling andfiltering the current output by the current generator, a current control system used for controlling a running state of each switching device in the current generator and adjusting the current outputby the current generator, a voltage control system used for driving on-off states of all the devices in the to-be-tested sub-module, and a cascade converter system model used for outputting the corresponding current and a voltage reference signal to the current control system and the voltage control system respectively. According to the test system, the simulation of the operation condition of anysub-module of a cascade converter can be realized, so that the test cost is saved, and the test efficiency and accuracy are improved.

The invention provides a preparation method of high-purity hydrogen bromide, and relates to the field of preparation of inorganic compounds. The preparation method mainly comprises the following steps: under the protection of inert gas, introducing chlorine into a metal bromide solution to prepare a mixture of bromine and metal chloride; and slowly raising the temperature, blowing out bromine, dehydrating the blown bromine through an adsorption tower, feeding the dehydrated bromine into a fixed bed filled with a catalyst, simultaneously introducing hydrogen into the fixed bed for reaction to prepare a hydrogen bromide crude product, condensing, adsorbing and dehydrating the hydrogen bromide crude product, and then, rectifying through a two-stage rectifying tower to prepare the high-purity hydrogen bromide. Chlorine and metal bromide are adopted as raw materials, and the raw materials are convenient and easy to obtain; bromine is generated in the reaction process and then reacts with hydrogen, so that the problems of bromine storage and transportation, waste packaging material treatment and the like are solved. Meanwhile, the method is simple and stable in reaction, easy to operate and control and suitable for large-scale industrial production.

The invention discloses a kit for rapidly extracting gram-negative bacterium genome DNA. The kit comprises a working solution A, a working solution B, a magnetic bead binding solution, a working solution C and a working solution D. The extraction method using the kit is simple, and mainly comprises the following four steps: bacterial lysis, magnetic bead adsorption, washing and elution. Monodisperse and superparamagnetic silicon oxide nano magnetic beads are adopted, other required reagents are conventional non-toxic reagents, the cost is low, the experiment safety is improved, and an extracted gram-negative bacterium genome DNA fragment is good in integrity, high in yield, high in purity and suitable for downstream molecular biology experiments such as PCR detection, nucleic acid hybridization and DNA library construction.

The invention discloses a carbon fiber electric atomizing ionization device and a method for realizing electric atomizing ionization by using the device. The carbon fiber electric atomizing ionization device comprises a carbon fiber bundle used as an electric atomizing base; a fixed pipe sleeves the carbon fiber bundle; a carbon fiber bundle end penetrating out from the front end of the fixed pipe is a sampling and electric atomizing end; a carbon fiber bundle end penetrating out from the rear end of the fixed pipe is fixedly provided with a conductive metal foil; the conductive metal foil is connected with a positive electrode of a high-voltage power supply. The method for realizing the electric atomizing ionization by using the device comprises the following steps: introducing a sample into the sampling and electric atomizing end; switching on a power supply to raise voltage to ionization voltage of electric atomization so that the electric atomization is carried out by the sampling and electric atomizing end. The carbon fiber electric atomizing ionization device has the advantages that sampling, cleaning and reutilization are very convenient, also has the advantages of simple structure, low cost, high safety, strong universality, wide application range, easiness for realization and the like, and has an obvious popularization and application value.

The invention discloses a micro analog power transmission line comprehensive experiment cabinet for a power system. The micro analog power transmission line comprehensive experiment cabinet for a power system includes a comprehensive experiment cabinet, wherein the comprehensive experiment cabinet is provided with a plurality of micro standardized analog power transmission line unit slots, a plurality of micro standardized analog bus unit slots, a plurality of light synchronous phasor measurement unit slots, at least one network switch slot and at least one junction box; and each of the microstandardized analog power transmission line unit slots is provided with a micro standardized analog power transmission line unit, and each of the micro standardized analog bus unit slots is provided with a micro standardized analog bus unit, and the micro standardized analog bus unit is provided with a micro standardized analog bus unit; each light synchronous phasor measurement unit slot is provided with a light synchronous phasor measurement unit, and the network switch slot is provided with a network switch. The micro analog power transmission line comprehensive experiment cabinet for a power system has the advantages of high simulation precision, easy structure adjustment, high integration level, high response speed, high timeliness, stable network transmission, and seamless integration with server applications.

The invention relates to an experiment apparatus for electrokinetic remediation and a use method. The experiment apparatus includes an experiment test unit, a flow-gas detection unit and a power supply unit; the experiment test unit includes a test body, potential measuring probes and electrode assemblies, wherein the anode of one of the electrode assemblies is electrically connected with the positive pole of the power supply unit, the cathode of the other electrode assembly is electrically connected with the negative pole of the power supply unit; and the flow-gas detection unit includes a first test piece for testing liquid flow and a second test piece used for testing gas flow. The method includes the following steps that: fine sand is preprocessed; a simulated soil filling chamber is filled with clean fine sand particles; perfusion of a saturated NaCl solution is carried out; and voltage change between the potential measuring probes is measured through controlling variables. With the experiment apparatus for electrokinetic remediation and the use method of the invention adopted, laboratorial simulation of salinized and alkalinized soil suffering from seawater intrusion can be realized, and an experiment can be simple, accurate, automated and miniaturized. The device is low in cost.

The invention discloses a popcorn experimental apparatus and belongs to the field of experimental equipment. The popcorn experimental apparatus comprises a heating disc, a glass cover, a heater and a rocker. The heating disc is rested above the heater though the rocker. The glass cover covers the heating disc. A discharge pipe is connected to the top of the glass cover. The popcorn experimental apparatus is simple in structure and easy to implement; the whole experimental process is unattended; students can have a visual, comprehensive understanding of the popcorn making process; a high temperature resistant seal ring helps enhance airtightness of the heating disc and the glass cover so that experimental effect is better.

The invention discloses a trace shellfish DNA extraction method for high-throughput sequencing library preparation. Micro shellfish gill filament tissue is selected, only a cell lysis solution and protease K are needed for cell lysis, protein digestion and supernatant dilution, and obtained genome DNA can be directly used for preparing a high-throughput sequencing library. The tissue amount required by DNA extraction is as low as 5 mg, the operation is simple and rapid, and the method is particularly suitable for preparation of the high-throughput sequencing library of the micro tissue. The library prepared from the DNA sample is used for sequencing to obtain genotyping data, and the typing accuracy is up to 99.94%. The DNA extraction operation time is not longer than 30 minutes, and the extracted DNA is suitable for preparation of the high-throughput sequencing library of a large quantity of shellfish trace samples and subsequent whole genome typing analysis.

A long exposure imaging-based equivalent fuzzy moving target image simulation method and a long exposure imaging-based equivalent fuzzy moving target image simulation system belong to the motion analysis part in the ordinary image data processing or production field. The method includes the following steps: according to a real fuzzy moving target image, another group of parameters are obtained by backward induction, the light intensity and moving speed of a substitutive target, the lateral magnification of a substitutive optical system and the exposure time of an image sensor are adjusted, the grey value is adjusted, and thereby a result which is the same as the fuzzy moving target image is obtained. The system adopts the image sensor to cooperate with the substitutive target, the exposure time of the image sensor can be adjusted, the image sensor can carry out long-exposure time imaging, and the substitutive target can two-dimensionally move in the direction of the vertical optical axis within the field range of the substitutive optical system. The method and the system can use a low-temperature target or a visible target to equivalently substitute for a high-temperature target and low-speed motion cooperating with long exposure time to equivalently substitute for high-speed motion, consequently, the difficulty of an experiment is decreased, the safety of the experiment is enhanced, moreover, multiple groups of experimental data can be easily obtained, and the experimental cost can be greatly reduced.

The invention discloses a mechanical arm control method based on model design, which is specifically implemented according to the following steps of performing three-dimensional model design on a mechanical arm by using SOLIDWORK software according to the application and the function of the mechanical arm to obtain a CAD file; configuring and exporting a URDF file for the obtained mechanical arm CAD file, importing the URDF file into GAZEBO software in an ROS system to obtain a robot model, and importing the URDF file into an SIMULINKN module in MATLAB software to obtain the robot model; usingRVIZ software to carry out motion planning verification on the obtained robot model in the GEZEBO software to verify the correctness of the robot model, and using an SIMULINK robot model obtained through the SIMULINK design mechanical arm motion planning verification model in MATLAB software to perform motion planning to verify the correctness of the SIMULINK robot. and finally, verifying the correctness of a semi-physical simulation model by using an MATLAB and ROS joint simulation model designed in the MATLAB software. Physical prototype test kinematics trajectory planning is realized, thereliability of a physical prototype is verified, and mechanical arm control is completed. The problem that in the prior art, errors are prone to occurring, and consequently development is repeatedly debugged is solved.

The invention provides a multifunctional pickling table device, which comprises an equipment body and a control device, wherein an operation platform is arranged in the middle of the equipment body, and an acid tank and a water washing tank are arranged on the operation platform; a mechanical arm for controlling a sample to move is arranged above the operation platform; an air exhaust system is arranged on the circumferential side wall of the operation platform; and the control device controls the movement of the mechanical arm and controls the cleaning procedures of the acid tank and the water washing tank. According to the multifunctional pickling table device, the problems of few types of acid tanks of a manual pickling table, single wafer size, incoherent process flow, tedious use process and the like are solved, and the safety and the convenience when the equipment is used are greatly improved.

The invention discloses a device for conducting a soil around pile destruction test. The device comprises a base plate, a fixing frame, a container, a pressure device and semi-section piles; the fixing frame is fixedly installed on the upper face of the base plate, and the height of the fixing frame is adjustable; the container is arranged between the fixing frame and the base plate, the side wallof the container is of a transparent structure, and first universal wheels are uniformly arranged on the bottom face of the container; the pressure device is downwards installed on the fixing frame;the bottom ends of the semi-section piles are inserted into the container, the top ends of the semi-section piles are detachably connected with the bottom face of the pressure device, and the side planes of the semi-section piles make contact with the inner wall of the container. According to the device for conducting the soil around pile destruction test, the height of the fixing frame can be flexibly adjusted according to the height of the semi-section piles and the height of the container; and universal wheels are uniformly arranged on the bottom face of the container and the bottom face ofthe base plate, flexible movement can be achieved, and manpower and material resources are saved.

The invention discloses a green technology for preparing dioxopromethazine hydrochloride by using oxygen as an oxidant, and belongs to the technical field of medical intermediates. The green technology is characterized in that a target product-the dioxopromethazine hydrochloride can be obtained through a series of reaction by using the oxygen as the oxidant and adopting palladium acetate as a catalyst, and a production process is greatly simplified; compared with a method of using hydrogen peroxide as the oxidant, the yield of an intermediate is much higher, a whole oxidation process requires no addition of sulfuric acid or the hydrogen peroxide, a final product is powder which is white to yellowish or crystalline powder, and the final product is odorless and is bitter in taste and very high in purity. By adopting an improved synthesis path, the green technology disclosed by the invention has multiple advantages that the yield is increased to a large extent, the cost is reduced, safety is increased, energy is saved, and the like, and modern chemical industry production requirements of green reaction are met.

The invention relates to a preparation method and application of low-cost liquid polycarbosilane. Halogenated methyl alkoxy silane and unsaturated halogenated alkane are used as reaction raw materials, a Grignard coupling reaction is performed to obtain a polycarbosilane intermediate, a low-cost reducing agent is added, a reduction reaction is performed to obtain hydrogenated polycarbosilane, and after the reaction is finished, a neutralization reaction and acid liquor washing are performed to obtain liquid polycarbosilane. According to the method disclosed by the invention, expensive lithium aluminum hydride is replaced by reducing agents such as lithium hydride which is low in cost and easy to obtain, so that the cost can be greatly reduced, and the operation safety is also improved; in addition, a high-boiling-point solvent is adopted to replace a traditional volatile ether solvent, solvent volatilization is reduced, meanwhile, solvent recycling is facilitated, and the preparation cost is further reduced. The method is low in cost, high in safety, high in operability and convenient for large-scale production, popularization and application. The obtained polycarbosilane is good in room-temperature fluidity and high in ceramic yield, can be used for preparing a ceramic-based composite material and can also be used for modifying the composite material.

The invention discloses an experiment table based on a robot. The experiment table comprises a pedestal, an experiment bin is arranged on the pedestal, a reaction container is arranged in the middle of the interior of the experiment bin, a material taking mechanical arm is arranged at the position, corresponding to the upper portion of the reaction container, of the top of the experiment bin, a medicine tank is fixedly arranged on the inner side edge of the experiment bin, and a sealing plug is arranged at the top of the medicine tank. The experiment table based on a robot is ingenious in structural arrangement, and when the experiment table works, an industrial control host controls the material taking mechanical arm to take materials from the medicine tank and put the materials into the reaction container for an experiment. A robot operated experiment is realized, and the experiment safety is improved. The invention further provides a heating mechanism, an alcohol lamp is arranged corresponding to the reaction container, and an igniter is arranged corresponding to the alcohol lamp. A camera used for experiment recording is further arranged on the top of the inner side wall of the experiment bin. An observation window corresponding to the reaction container is arranged on the side wall of the experiment bin; and the manual operation is facilitated.

The invention discloses a preparation method of a peel strength test sample and the peel strength test sample. A glass substrate, a spacer, a first PVB plate and a metal back plate are sequentially stacked; wherein the length of the spacer is smaller than that of the glass substrate, and the length of the first PVB plate is larger than that of the spacer; and laminating and fixing, and extracting the spacer to obtain the peel strength preparation sample piece. Therefore, the second PVB plate, the metal back plate, the first PVB plate, the isolation sheet and the glass substrate are packaged, on one hand, a peeling strength test does not need to be carried out by adopting a finished photovoltaic module, the test cost can be reduced, the test period can be shortened, photovoltaic module manufacturers can conveniently adjust lamination parameters in time, and the production efficiency and the production utilization rate are improved; and on the other hand, related data of the glass strength test can be obtained without a falling ball experiment and a shotgun shot experiment of the PVB packaged photovoltaic module, and the experiment safety of the glass strength test can be improved.

The invention discloses an extraction device for an anionic synthetic detergent in water. The extraction device comprises a support frame, a first container and a second container; a first placing frame and a second placing frame are movably connected to the support frame; the first container and the second container are respectively placed in the first placing frame and the second placing frame;switching valves are arranged at the lower parts of the first container and the second container; a connecting pipe is arranged at the lower part of the first container; the free end of the connectingpipe is arranged above the second container; a first cover body and a second cover body are respectively arranged at the upper parts of the first container and the second container, the upper part ofthe support frame is fixedly connected with a box body, a control device is arranged in the box body, two stirring rods are arranged on the control device, and the free ends of the stirring rods penetrate through the cover bodies and then are arranged in the first container and the second container. The extraction device has the advantages of simple operation, convenience in use, high extractionefficiency, automatic exhaust and prevention of trichloromethane volatilization caused by palm temperature of an operator.