The product main body is ABS, objective lens and eyepiece adopt metal aluminum alloy, the platform use aluminum alloy. We main have white, gray, yellow, green, rose red five colors, if you want other colors, you can customized from us. With this extraordinary microscope you will be able to explore a hidden world of microscopi wonder thanks to the cool, dual LED illumination. Overhead illumination allows for the study of soiled objects at up to 100× magnification! Sub-stage illumination from the base allows for the study of specimens on slides, such as plant and animal cells, hairs, fibers, and so much more at up to 400× magnification!
With your microscope and fun activity booklet included with it, you are prepared to explore a whole new microscopic world where amazing discoveries await you!
Student's biological microscope Safety:
. The Young Scientist Dual Scope is a scientific instrument and kit containing glass slides,staining chemicals, and other potentially sharp instruments. As such, it is recommended and intended for mature users aged 9+ up.
. Adult dupervision is required for experiments and slide preparation.
. Store your instruction manual safely alongside your microscope and keep on hand for reference when performing experiments.
. Always set up your microscope on a smooth, level surface such as a table or a desk.
. Always make sure to keep your microscope stored in a cool dry place, and cover with the dust cover provided when not in use.
. Handle all equipment whith care. Glass slide and lens optics are extremely fragile. Do not use if they appear cracked or broken.
. Do not mix old and new batteries. Never mix alkaline, standard (carbon zinc) or rechargeable (nickel-cadmium) batteries.
. Please remember to follow all appropriate safety & operating procedures outlined in this manual.
Biological microscope for student Specifications:
. 10× Magnification Wide Field Eyepiece
. 360° Rotatable Head
. 4×, 10×,40× Objectives
. Dual LED Illumination
. Dual Focusing Knobs
. 6 Hole Disc Diaphragm
. Light Intensity Control
. Real Optical Glass Lenses
Dimensions: 165mm×114mm×292mm
Net Weight: 0.9kg
Power: 3AA battteries (Not Included)
Magnifications:
Calculations for total magnification are achieved by multiplying the magnification of your microscopes eyepiece (10× eyepiece included with this kit) by the magnification of objective lens.
*The 40× lens is not suitable for Macro Observation with upper lighting due to the focusing distance required.
Biological microscope for children Accessories:
Your Young Scientist Dual Scope comes packaged with the following accessories to help your discoveries.
. 5 Blank Slides
. 4 Prepared Slidea
. 1 Concavity Slide
. 2 Bottles of Non-toxic Stain (Red& Blue)
. 1 Pair of Tweezers
. Slide Labels
. Cover Glass
. Lens Paper
. Staight Teasing Needle
. Plastic Perti Dish
. Plastic Test Tube
. Plastic Dropper
. Dust Cover
. Instruction Manual and Fun Activity Booklet
Maintenance & Care:
In order to prolong the life of your microscope please follow these important care and maintenance instructions.
Your microscope comes in a Styrofoam case which protects the instrument during shipping and transportation. Please keep the original Packaging in the event a microscope needs to be returned for servise or repair,
Always store your microscope in a cool, dry place, replacing it into the box when not in use, or covering it with the dust cover. Keep the lens objective in place in themicroscope when not in use to avoid dust and figerprint contamination and always avoid touching the glass optics.
Should your optical surfaces and lenses become dusty and smudged, blow gently on the surface to remove loose dust and dirt particles.
If the lens is still smudged or dirty, wiping with lens paper will clear up smudgeds. For persistent smudges, use a mixture of rubbing alcohol diluted with water to remove the contaminant. Wipe on with lens paper or a soft, cotton and gently wipe dry.
Always turn off LED illuminators when not in use.
The production of Biological microscope for student:
Aluminum Children Microscope Gift Toys Children Microscope Toys, Children Gift Microscope, Aluminum Children Microscope NINGBO BEILUN LEMA MACHINERY TECHNOLOGY CO.,LTD , http://www.china-lema.com
Biological microscope for students Product Introduction:
Application of Partial Discharge Detector in Large Motor
1.1 Foreign Development
Since the 1950s, a large amount of research work has been carried out abroad on this technology, and this technology has made great progress. According to reports, tens of thousands of foreign motors have adopted on-line monitoring technology and have achieved very good results. Its technology has gradually transitioned from narrowband systems to broadband systems and to ultra-wideband systems.
In foreign countries, a variety of technologies have been successfully applied to the local detection of motors. These methods mainly include the following:
(1) Neutral point coupling monitoring method
Since the arc discharge in any part of the motor will generate a corresponding RF current in the neutral point grounding line, the partial discharge monitoring point can be selected at the neutral point grounding line. In the 50's, Westinghouse developed an on-line monitoring system for generator partial discharge. The working principle is that the discharge signal is drawn from the neutral point of the stator winding and sent to the oscilloscope through a band-pass filter to display the time domain waveform of the signal on the oscilloscope screen. In practical applications, noise signals and discharge signals must be identified by experienced operators, and it is difficult to promote them.
(2) Portable capacitive coupling monitoring method
In the 1970s Ontaio Hydro of Canada developed an on-line monitoring device for partial discharges. To monitor the discharge signal, three capacitors (375pF each, 25kV each) were lapped on the generator 3-phase outgoing line, introduced into the oscilloscope through (30kHz to 1MHz), and the time-domain waveform of the discharge signal was displayed. This method was applied at some Canadian power plants and achieved good results. Its drawback is still relying on experienced operators to distinguish between external interference signals and internal discharge signals, resulting in the promotion of this monitoring method has been limited.
(3) Radio frequency monitoring
The radio frequency monitoring (Radio Frequency Monitoring) method is actually a method improvement proposed by Johnson. This method uses a high-frequency current sensor, Rokowski coil RC capacitive-capacitive high-pass filter to pick up high-frequency discharge signals from the generator stator winding neutral line to discover the internal discharge phenomenon of the stator coil. At present, it has been used in many generators and large-scale high-speed AC motors, and has achieved good results. In 1980, Westinghouse developed a commercial RF monitor with an amplifier center frequency of 1 MHz, a bandwidth of 5 kHz, and an alarm circuit.
(4) PDA monitoring method
PDA is the abbreviation of Partial Discharge Analyzer. The PAD monitoring method was introduced by Ootaio Hydro in Canada in the 1970s. It is mainly used for on-line monitoring of partial discharges inside a hydroelectric generator. It uses the characteristics of the discharge signal in the winding and the external noise signal to suppress the noise when it propagates in the winding and extracts the discharge signal. The PAD test method has been adopted in the on-line monitoring of foreign hydroelectric generators.
(5) Slot coupler (SSC) monitoring method
Because the structure of the stator winding of the turbine generator is different from that of a hydroelectric generator, the PDA test cannot be satisfactorily applied to on-line monitoring of the turbo generator. In 1991, Ontaio Hydro and Iris Power Enginrrring used TGA (Turbine Generator Analyzer) for on-line monitoring of partial discharge signals of turbine generators. This method is relatively costly and requires a special device—Stator Slot Coupler (SSC)—to be buried under the slot wedges of each slot of the stator. The SSC is used to detect the discharge pulse of each slot. For generators that have been put into operation, stator windings must be modified before implementation, which is often unacceptable for power plants.
(6) Resistance temperature measuring element monitoring method
The use of resistive RTD conductors embedded in certain slots in the stator as discharge sensors to measure partial discharge pulses has no effect on the primary circuit of the motor. This PD sensor has a wide frequency characteristic (3 to 30 MHz), which makes it easy to distinguish between PD pulses and noise. However, since the dual-sensor ratio method is used to distinguish between signal and noise, it is impossible to distinguish the partial discharge signal and noise in some parts of the motor.
1.2 Domestic research
Domestic studies on line monitoring have started late and development has been slow. In particular, due to the complexity of the partial discharge process, the current theory is still imperfect and the research on this area has brought great difficulties. In 1990, Shanghai ranked "Radio Frequency Monitor" as a scientific and technological research project, and was awarded the second prize by Shanghai Second Polytechnic University and Shanghai University of Science and Technology at that time. It was completed in May 1992 and passed the appraisal in October. The radio frequency monitor of Gongda University has been applied to many domestic motors, and the radio frequency monitor of HKUST has good application practice in Shanghai Power Plant. The two systems fully met Westinghouse’s product standards in the early 1980s. Its amplifier center frequency is 1MHZ, wideband 5kHz, device selectivity is good, antijamming ability is strong, but because the passband is too narrow, the information obtained is less, the sensitivity is low and does not have the partial discharge comprehensive characteristic analysis ability.
The DJYC-1 type electric motor bureau developed by Tsinghua University used a single-chip microcomputer to control the sampling system and used a combination of low-speed sampling and high-speed sampling. The low-speed sampling results were used to collect the amplitude and corresponding information of the discharge signal. The high-speed sampling results were used to analyze The subtle characteristics of the discharge waveform have achieved certain results.
The electric motor bureau developed by Xi'an Jiaotong University puts a wideband system on the line monitoring system, which can measure various characteristic quantities of partial discharge. Combined with modern digital processing technology, it has made some attempts in the automatic recognition of discharge types.
The on-line monitoring system developed by Shanghai Jiaotong University contains a narrowband system and a broadband processing system. The wideband system uses high-speed and long-time sampling. DSP and computer are used to process large amounts of data. The characteristic values ​​of the extracted signals are stored in the database. , Through the long-term monitoring of the motor to determine the insulation damage of the motor. Narrowband systems are used for comparative studies.
Technically speaking, domestically developed equipment can be divided into narrowband systems and broadband systems. For narrow-band systems, it is only sensitive to severe spark discharges at the late stage of partial discharge, and it cannot distinguish between on-board and off-board discharge signals as well as fault classification and positioning. For a broadband system, the wider the bandwidth, the richer the PD information collected, but the higher the system requirements. On the one hand requires a higher sampling rate and digital processing capabilities, on the other hand the identification of interference is also the key.
1.3 Signal propagation characteristics and impact of the test system
(1) The partial discharge signal is a high frequency signal. Since the stator coil has a large inductive reactance, it is a complicated LCR network.
The arrival of the sensor from the point of release to the sensor will cause great distortion and oscillation, which will seriously affect the test results. For general samples, BG7354-87 specifies partial discharge measurement and calibration methods, but the current partial discharge calibration method is not suitable for the calibration of the discharge capacity of large generator stators. A working group of the IEEE Institute of Electrical Engineering is drafting a guideline (P1434) on this issue, reminding people to pay attention to the different interpretations of the results of the motor stator partial discharge test.
(2) Different test systems are involved except that the attenuation and oscillation of the PD signal during propagation have a serious impact on the test results.
The test result of the PD signal also has a great influence. According to the report [3], in a partial discharge inspection of a 4kV motor, four commercial broadband partial discharge test systems perform apparent charge calibration according to the recommended method of ASTM-D1868, but they test the same partial discharge signal. The results were expressed as PC (pico) from 60 PC to 1000 PC, and the test results for the same motor differed by 17 times. The impact of the test system on the test results is mainly due to the wideband, input impedance, input sensor, and sensor installation location of the different test systems.
Based on the above reasons, when analyzing the results of the line test, the test system and test methods should also be considered together. The test results of different test systems and the test results of different motors are not comparable. In this sense, the interpretation of the results of the PD test results tends to be more valuable over time.