二手 VARIOUS Lot #9217380 待售
网址复制成功!
单击可缩放
ID: 9217380
Lot of spare parts:
Qty / Make / Part number / Description
(26) / STREAS / 0002 / Collar serr DN20 / 25 kf
(2) / STREAS / 0003 / Collar serr DN32 / 40 kf
(24) / STREAS / 0003-SS / Stainless steel collar with DN32 / 40kf
(50) / STREAS / 0029 / Griffa wall DN25 kf
(3) / - / 005774 / Carrier 900 chain connections
(34) / STREAS / 0081 / Centering rings inox DN16KF guarniz.v
(58) / STREAS / 0083 / Centering rings inox DN25KF guarniz.v
(53) / STREAS / 0085 / Centering rings inox DN40KF guarniz.v
(4) / - / 010109 / Top stiffener 813-20-035
(4) / - / 010110 / Stiffeners
(208) / - / 010139 / Platelets
(12) / - / 010309 / Adjustment screw bases
(1) / - / 010311 / -
(3) / GOMEC / 010415 / Blank off flanges V4 special
(7) / - / 010438 / Adapter flanges V4-Kf25 010438
(4) / GOMEC / 010671 / Stand offs
(5) / - / 0111 / Blank offs Kf16
(5) / - / 011316 / Guides support with carriers stop for (600) verticals 813-28-701
(4) / - / 011398 / Panel air attacks and N2 purge in
(3) / - / 011399 / Distances
(8) / - / 011466 / Pin 0.3 D) H = 5.5 mm
(2) / WITT ITALIA / 011490 / Gas pipings
(37) / STREAS / 0115 / Blind flanges DN40KF - AISI 304
(2) / OLL / 011549 / Internal support panels
(3) / OLL / 011550 / Bracket assys manifold grippers smc
(2) / OLL / 011551 / Internal support panels
(4) / STREAS / 011554 / Floor in drawing 011554 AISI 305
(2) / OLL / 011563 / Panel internal supports
(2) / WITT ITALIA / 011571 / Gas tubes
(2) / WITT ITALIA / 011573 / Vent gas tubes
(2) / WITT ITALIA / 011574 / Gas tubes
(4) / STREAS / 011576 / Pipe lines rough 600
(3) / OLL / 011631 / Dark brackets optical sensors
(10) / GOMEC / 011635 / Right holding locks
(10) / GOMEC / 011636 / Left hold blocks
(13) / NECO / 011656 / Column for plexiglasses cover 011655 l = 51 mm
(25) / NECO / 011657 / Column for plexiglasses cover 011655 l = 14 mm
(24) / GOMEC / 011661 / Pin containers wafer Sp 0.5mm
(6) / GOMEC / 011680 / RF Network clamp tubes 011678 + 011679
(17) / NECO / 011713 / Upper frames thickness MRC 600
(7) / OLL / 011716 / Bracket grippers for assy manifold
(8) / - / 011720 / Union 1/2 2u Universal racks
(16) / STREAS / 0155 / Stainless steel reductions DN40 / 25kf
(3) / STREAS / 0165 / Straight fittings 40kf - AISI 304
(2) / STREAS / 0205 / Flexibles inox DN16kf l = 500
(1) / STREAS / 0209 / Flexible inox DN25kf l = 500
(5) / STREAS / 0210-R / Flexibles DN25kf l = 750 annealed - AISI 304 flange / AISI 316 tubes
(1) / STREAS / 0211 / Flexibles inox DN25kf l = 1000
(4) / STREAS / 0211-R / Flexibles inox DN25kf l = 1000 AISI 304 flange / AISI 316 tubes
(4) / STREAS / 0213-R / Flexibles DN40kf l = 500 annealed - AISI 304 flange / AISI 316 tubes
(2) / APE AUTOMAZIONE / 026136 / Nipples API 1
(1) / APE AUTOMAZIONE / 026164 / Elbow API inox MF1/2 1/4
(5) / SIGMA / 02853-2.5L / Ethanol, denat with 4.8% isopropanols
(2) / STREAS / 0305-90° / Fitting 90 ° DN40
(5) / STREAS / 0310 / Tee DN10kf
(17) / STREAS / 0313 / Fitting tees inox DN25kf
(13) / STREAS / 0601 / Flanges cieca cf35 / 40 - AISI 304
(9) / OLL / 1053 / Central portamagnetis
(1) / SHT POWER SAS / 1111EGR0T15K / Egrt continuity group 1.5k
(1) / SHT POWER SAS / 1133EAS400MSM / Electronic card relay mini slot with connector
(26) / STREAS / 1144 / V4 blank flanges
(2) / C.T.E. AUTOMATION / 1251/B-14 / Choke ft 1251 / 5-14 for anticreep valve 600
(2) / - / 1666 / Etch lamp door cover plate 603/643 etch shields
(1) / - / 1718 / 3u Rack panel
(66) / GORLA / OR 2012 / O-rings gas leads
(113) / GORLA / OR 2018 / O-rings sealscrews with 2 008
(30) / GORLA / OR 2025 / Or2025 vco 1/4 fittings
(22) / GORLA / OR 2037 / O-rings cathode inset blank offs
(48) / GORLA / OR 2056 / O-rings vitons
(9) / GORLA / OR 2075 / O-ringss or 2075
(11) / GORLA / - / O-ringss id 2.239
(24) / GORLA / OR 3037 / O-ringss viton
(20) / GORLA / OR 3043 / O-rings sviton, parker 2-111 .424 3043
(19) / GORLA / OR 3056 / O rings
(20) / GORLA / OR 3062 / O-rings viton, 2-114 .612x.103
(22) / GORLA / OR 3068 / O-rings or 3068 or 3068 ultratorr 1/2 ion gauge batch
(31) / GORLA / OR 3075 / O-rings
(47) / GORLA / OR 3081 / O-rings id .799x.103 or 3081
(14) / GORLA / OR 3150 / O-rings viton for compressor cti
(16) / GORLA / - / O-ringss viton parker 2-134
(8) / GORLA / - / O-ringss id2.737cs103
(27) / GORLA / OR 3325 / O-ringss 900/943 etch bellows or 3325
(22) / GORLA / OR 3425 / O-ringss viton
(23) / GORLA / - / O-rings 4.487x.103
(17) / GORLA / - / O-rings etch 8667 6.487x.103
(29) / GORLA / OR 3825 / O-rings id 8.237x.103 cryo pump
(63) / GORLA / OR 4024 / O-rings pallet sensor feedthrough diam. 5.94 sez. 3.53 or 4024 va
(24) / GORLA / OR 4036 / O-rings viton gas ring batch
(54) / GORLA / OR 4067 / O-rings .671x.139 2-209
(51) / GORLA / OR 4075 / O-rings 739x139
(20) / GORLA / OR 4087 / O-rings 4087
(47) / GORLA / OR 4100 / O-rings per flage heat lamps e flage cieche stud 600 ll or4100
(50) / GORLA / OR 4106 / O-rings heater blank off batch or4106
(4) / GORLA / - / O-ringss 1.359x.139
(62) / GORLA / OR 4143 / O-rings for v4 flange
(35) / GORLA / OR 4150 / O-rings for viewport batch a110350
(8) / GORLA / OR 4162 / Or 4162
(16) / GORLA / OR 4175 / O-rings id 1.734x139 2-224
(43) / GORLA / OR 4187 / O-rings viton for gripper flange or 4187 2-225parker
(13) / GORLA / OR 4200 / O-rings id 1.984x.139
(42) / GORLA / OR 4225 / O-rings 4225
(4) / GORLA / OR 4250 / Temescal valves O-rings 600/900/643/943 batch
(26) / GORLA / OR 4275 / O-rings etch 2.734x139 2-232
(9) / GORLA / - / O-ringss
(12) / GORLA / OR 4325 / O-rings 4325
(16) / GORLA / OR 4375 / O-rings
(22) / GORLA / OR 4387 / O-rings ll door window
(18) / GORLA / - / O-ringss id 3.984 c/s .139
(12) / GORLA / OR 4437 / O-ringss bellow ll platform 600 / etch platform
(16) / GORLA / - / O-ringss 5.109x.139
(12) / GORLA / - / O-ringss
(22) / GORLA / OR 4550 / O-ringss ll bellows 600
(3) / GORLA / OR 4625 / Cti100 to cti8f O-rings for adapter cryo l/l
(7) / GORLA / OR 4700 / O-rings viton
(34) / GORLA / OR 4750 / O-rings viton eclipse star/uhv gate valve end plate.
(22) / GORLA / OR 4800 / O-rings viton 4800
(9) / GORLA / OR 4825 / O-rings cryo pump 2-267 4825
(7) / GORLA / OR 4975 / O-rings viton 9.75 rmx/spa cathode water
(32) / GORLA / OR 41050 / O-rings for gate valve esterno tenuta gate-camera
(5) / GORLA / OR 41100 / O-rings
(22) / GORLA / OR 41150 / O-rings used for spa12 teflon insulator
(10) / GORLA / OR 41200 / O-rings 943 ll door etc. 11.984 planar magnetron soft etch eclipse
(24) / GORLA / OR 41300 / O-rings viton 12.984 cs .139 for bp and cath.adapt. 12 and door
(22) / FP MILANO / OR 41400 / O-rings viton for cathode planar / inset batch o.r. 41400
(9) / GORLA / OR 41500 / O-rings cathode adapter for eclipse mark iv
(12) / GORLA / OR 6100 / O-rings viton 2-318 1x.21 6100
(10) / GORLA / OR 6175 / Or 6175
(23) / GORLA / OR 6200 / O-rings l/l rought 600
(9) / GORLA / - / O-rings 2-372 .275c/s x 8.725id
(19) / FP MILANO / OR 61700 / O-rings viton ll platform 900s o.r. 61700
(35) / FP MILANO / OR 61800 / O-rings viton seal plate 600s
(12) / GORLA / OR 8500 / O-rings 2-249 viton-for l/l platform weldment cup/hub
(29) / GORLA / OR 8700 / O-rings gate valve plate or 8700
(11) / GORLA / OR 8725 / O-rings viton for mrc star 6 gate valve
(23) / GORLA / OR 81850 / O-rings id 18.455 c/s .275
(2) / GORLA / OR 81950 / O-rings viton
(9) / GORLA / OR 82000 / O-rings viton
(21) / GORLA / OR 82100 / O-rings viton
(7) / - / - / Gasket, copper, 10cf
(36) / FP MILANO / - / O-rings chamber 903 1440x5.33
(25) / GORLA / - / O-rings ll rough line batch 900 1,85 id, 0,21 corda
(11) / FP MILANO / OR 754 / O-rings viton 754.18-5.33 ll 600s
(12) / FP MILANO / OR 1045 / O-rings viton 1045.76-5.33 chamber 600s
(1) / - / 2179A01322CR1BV / Mass flow 200 sccm
(3) / STOCCHETTA CILINDRI / 2-BJM-071312-01 / Hr5f-2.50x9.00-n-1.75-4m-n-h-n-1-1-x
(5) / WHITMAN CONTROLS CORPORATION / J705-3-F52L / Switches pressure 1000 hg +/- 50 incr. H hps ) j705-3-f52l
(7) / - / - / Handles
(5) / - / - / Handle inset cathodes
(27) / - / - / Connector receptacles
(2) / - / - / Lamp holders aDN braket
(10) / - / - / Standoffs 3/8 x 2-3/4 10-32thd
(2) / - / - / Standoffs,1/2x9x1/4.20 8740a1/4
(2) / - / - / Relays 40a 3p 240v with microswitch c3m40c
(5) / - / - / Contactor 50a 3m40a fasco
(2) / - / - / Phase monitor relays
(1) / - / - / Circuit breaker 10a 2 pole
(10) / - / - / Circuit breakers 3 pole 5a 250v
(15) / - / - / Circuit breakers 10A, 2 Pole
(5) / - / - / C3 0.01uf
(5) / - / - / Capacitors rf 100pf
(1) / - / - / Meter, 0-100ua
(10) / - / - / Resistors 37.4k ohmz
(1) / ADVANCED ENERGY / 3155403-001 / Navio sp2 13mhz, 3kw,n,mc6,15 pin, ac, dcb
(3) / - / - / Xmfr pc-8402 g/start
(5) / - / - / Wire solids teflon, 18awg
(1) / - / - / Tube 6155 buffer
(12) / - / 3427 / Panel 1/2 rack 2u for instruments
(1) / - / 3450 / Panel for eclipse 3450
(3) / METAL FLEX / 36426BB-2.5-MOD / Bellows od: 3.640 bellows id: 2.640 bellows material: 347 ss b-style 2.65" dia
(3) / OLL / 3893 / 4u racks panels
(7) / OLL / 3894 / 2u panel black racks
(1) / OLL / 3897 / 2u panel black racks
(3) / BROOKS / 3918059G005 / Rigid helium conduits, tee, 1/2" outer diameter, male-male-female
(4) / MKS / 392401-0-YE-T / Sensore granville-philips series 392 micro-ion plus micro-ion/conductron
(2) / - / - / Purge gas heaters CRYO
(1) / MKS / - / Baratron 100 torr
(2) / RS / 243-5919 / Gauge for water manometros 63mm 0-6 bar 243-5919
(6) / MKS / - / Baratron mods.141a-13670-s range 10torr
(5) / - / - / Hose rubbers
(2) / METAL FLEX / - / Bellows od: 4.750 bellows id: 3.750 bellows material: 347 ss
(1) / - / - / Desicant, bakeable trap
(8) / GRAINGER / 4TRH9 / Piedinis
(5) / - / - / Ftg union 1/4 tube x 1/4 tubes
(5) / - / MBH-1010-2 / Bulkhead fitting valves 1/8ftp
(2) / - / - / Union 5/16t x 1/4t ss-500-6-4
(2) / - / - / Union 1/4 ultra torr
(7) / - / MH-1016-303 / Ftg barb connectors
(2) / COSMOTECNICA / 0-MRS-124-DXPZ / Cylinder pneumatic 1-1/4x4 univ. Con slitta x sens l/l door eclipses
(11) / - / - / Valve, 2-way nc 1s/4npt
(4) / - / - / Skinner valve 120vac for air 7w
(4) / - / - / Unidirectional restrictosr 10-32
(1) / NORDIVAL / SS-BNV51 / Nupro valve 1/4 vcr female manual
(1) / - / - / Valve solenoid 4way 4vs-24vdc allenair
(5) / - / - / Check valve for manifold waters
(5) / - / CLITV3S / Switch air manual tv - 3s valvola a leva 3 vie
(18) / HELIPEBS CONTROLS / AB 90 / Switch coupler ab90
(9) / NORDIVAL / 321-4-X-2 / Flex tubes
(7) / NORDIVAL / 321-4-X-4 / Flex tubes
(3) / NORDIVAL / 321-4-X-12DFR / Flex tubes vcr l=12
(5) / NORDIVAL / 321-4-X-24DFR / Flex tubes vcr
(4) / CARABA / 51.592 / Keyboard stand for monitor bracket bracket 57.252 pcclean
(1) / PALL / SGLF6101VM4 / Gas filter
(12) / PALL / GLPF3000VMM4 / Gas filters glfpf3000vmm4
(25) / STREAS / 5111 / Blind flange DN 16kf aluminum
(2) / STREAS / 5209 / Flessibile inox DN25kf l=1500
(1) / STREAS / 5209-R / Flessibile inox DN25kf l=1500
(1) / - / 5308 / Cath cover mount brackets with swi
(12) / - / 5493-MOD / Bracket boxes for micros
(6) / OLL / 5633 / Washer
(8) / - / 5637 / Etch flex line insulators
(4) / CARABA' / 57.252 / Arm bracket monitors
(10) / - / 5845 / Shield carrier rights
(10) / - / 5846 / Shield carrier lefts
(10) / - / 5847 / Shield carrier bottoms
(3) / - / - / Bakelite rod loop
(16) / - / - / Clamp collar,1.25 bore alum hard etch) 1633
(28) / - / 10221 / Washer flat 900/603 shutter for view port batch Teflon 010221
(3) / - / - / Bearing , flanged 1/4d x 1/2 od
(749) / GRAINGER / 5BE23 / Roll pin ss 3/32x3/8 5be23
(150) / GRAINGER / 5BE30 / Roll pin 3-32x13/16 5be30
(11) / - / - / Scr, skt, 1/4 shol, 10-32 x 3/16
(4) / - / - / Scr,shc,ss,5/16-18x3-1/2
(6) / - / - / Nut,spring 1/4-20 larges
(8) / - / - / Nut 5/8-11 h=8.5mm
(3) / - / - / Washers
(39) / - / - / Flat washer for center support cathodes
(3) / - / - / Gears small
(2) / - / - / Gears big
(3) / - / - / Spring,extension EO2400342750
(2) / - / - / Rings retaining 4-1/4 dia int
(62) / - / UR-0187-S / Retaining rings
(100) / - / SH-0087-H / Seger external 0,875 sh-0087-h
(20) / - / 5DB93 / Retaining ring internal 1 3/8 5db93
(1) / - / 61300055 / Cesar 1310 aeuser profibus rf-generator with active front panels
(6) / - / 6131 / Etch flex line teflon ball insulators
(16) / - / 622004P / Fasteners
(1) / MKS BARATRON / 627A.11985 / -
(1) / MKS BARATRON / 627A.1TOD / 1 torr
(1) / MKS BARATRON / 627DX01TBC1B / 627dx01tbc1b 1 torr
(1) / MKS BARATRON / 628A.14616 / -
(10) / - / 6385 / RF Soldering brackets long
(23) / - / 6387 / RF Soldering brackets short
(1) / ADVANCED ENERGY / 69200206 / Control cable for vm and navio matches with cesar generators - lengTh 10 m -
(16) / ALLIED ELECTRONICS / 70211349 / Spacer; 6-32; 1/2 in.; ceramic; 3/8 in.; round; mil nl 523w01 004) insulator x bias anode 900
(3) / - / 73 1 45 65 / Variable capacitor eclipse network
(5) / RS / 748-336 / Universal side joint 1/4"-1/4" 207.18.2424
(3) / 40-30 / 8033167 / Cryopump mod. Ct-8
(1) / 40-30 / 8033167R / Cryo-torr cryopump,8, 8 ansi flange, chevron frontal array, temperature sensor,enhanced array set, purge tube, 2 Phase motor - exchange -
(1) / 40-30 / 8033168R / Cryo-torr cryopump , 8, 8 ansi flange, chevron frontal array, enhanced array set, vapor pressure gauge, purge tube, 2 Phase motor - exchange -
(1) / 40-30 / 8033295 / Cryo-torr 8f cryopump
(1) / 40-30 / 8033295R / Cryo-torr cryopump, 8f, 8 ansi flange with vent, chevron frontal array, 2 phase motor, special lines exchange
(3) / - / 8042003 / Temperature sensor assy
(1) / CTI / 80432023G003 / On board frequency converter cti sn j0602915
(1) / CTI / 8043202G003 / On board frequency converter cti sn j0602915
(2) / - / 8044051 / N2 gas heater CRYO
(1) / BROOKS / 8080300K001 / Kit adsorber 9600/9700a compressors
(1) / 40-30 / 8107108R / I/i ct8f mrc with 662 lines
(2) / 40-30 / 8116214G002R / I/i 8 ANSI ch kpd w/fstrgn
(3) / STREAS / 8121 / Fl.a sald. DN16kf l=42 mm
(4) / OLL / 10515 / Lower shield chain guard outside 010515
(1) / GIRMEC / 10082 / Seal plate 010082
(20) / RS / 858-3421 / Strain 8/7,5mm
(1) / MKS / 979B-41 / Vacuum gauge multi ranges
(4) / WATLOWITH 988-S HOUSING / Housing WATLOW 998-s control
(1) / PINEUTRONICS / 990-4350-082 / Pcb
(2) / APE AUTOMAZIONE / A002-MAN40-0110 / Pressure gauge 40 1/8" post. 0:10
(6) / DISCREET INDUSTRIES / A121611 2023780 / O-rings viton load lock door)
(2) / PFEIFER VACUUM / ACP40 / Dry primary pump frictionless, multi-roots, gas ballast manual
(4) / APE AUTOMAZIONE / AF220-1F-01-06S / Top grippers reducer
(4) / APE AUTOMAZIONE / AF220-1F-02-06S / Bottom grippers reducer
(1) / - / B-U0117 / Tfe943 sputtering systems
(10) / SARONTECNICA / CH-RS-25-1-SS / Tsubaki vacuum chain - pack std. Mt.3,05 -
(6) / MDC VACUUM / CHV12-30C / 9431001 Power feedthrough weldable 10kv 30a 1 -pin passante elettrico
(8) / - / CTTHERM500-4/00 / Insulator 6 heater backplanes
(2) / BIELLEBI / ET0788 / Eurotek relay cards
(2) / BIELLEBI / ET8730 / Eurotek interface cards
(2) / BIELLEBI / ET8731 / Eurotek interface cards
(3) / - / EVK06-C5-24D-DN / Anticreep valve 600 EVK06-C5-24D-DN-DG 3/8 b-1158)
(3) / ANGSTROM / EVR5470001 / Repair/Rebuild of Onyx-547
(3) / MITSUBISHI / HG-MR43 / Motor for servo drive MR-J4 new code from 16/5/16)
(50) / - / KL-RS-25-1-SS / Tsubaki joint
(4) / CD ELETTRONICA / LGKMC1050 / Mini tast + touch ack-540 nera usb tac540u
(4) / MITSUBISHI / MR-BAT6V1SET / Batteria servo mr-j4
(5) / E.M.A. CEREDA / NSYS3X4620 / Schneider stainless steel box PLC box
(1) / PTB SALES / OEM2000 / ENI Power supply 2000w 13.56 MHz
(4) / FP MILANO / OR 374X6 FKM70 / O-rings 374x6 materiale FKM70, per catodi tfc 3x17
(6) / APE AUTOMAZIONE / PF3W704SF03BTNM / Flussimetro acqua network con contr.temp.
(50) / - / PP5/2000/25.5/1 / Magnetic tape for hard etch doors
(9) / - / PT06A-12-10P / Amphenol military connector for batch network tune signals
(3) / MITSUBISHI / Q312B-E / Basic rack 12 i / o positions
(18) / MITSUBISHI / Q32CBL-3M / Q32cbl-3m connection cables for qx81 / qy81p modules length 3mt
(3) / MITSUBISHI / Q61P / Input power supply 100-120vac output 5vdc / 6a
(9) / MITSUBISHI / Q68ADV / Analog module for 8-channel voltage inputs
(4) / MITSUBISHI / Q68DAVN / Analog output module with 8 current channels
(1) / MITSUBISHI / Q6TA32 / Idc adapter for mitsubishi 32-point i / o modules replaced by a6con4
(4) / MITSUBISHI / QD75MH1 / 1 axis control modules
(4) / MITSUBISHI / QJ71PB92V / Master module for profibus-dp networks
(7) / MITSUBISHI / QX81 / Entry module from 32 points to 24 vdc
(7) / MITSUBISHI / QY81P / 32-way digital output modules
(2) / STRREAS / R00001 / Kf25 90? Vcr 4m
(7) / - / R00002 / Cti joints
(5) / NORDIVAL / SS-1010-1-6 / Straight fittings 5/8 3/8
(10) / NORDIVAL / SS-400-2-2 / Male elbows 1/4 swas - 1/8 npt
(50) / NORDIVAL / SS-400-6 / Union 1/4 swas
(10) / NORDIVAL / SS-400-71-2 / Bulkhead females conn 1/4 swa
(30) / NORDIVAL / SS-405-170 / Inserts 1 / 4swa-170 swa
(30) / NORDIVAL / SS-405-2 / Inserts 1/4 swa - 1/8 swa
(3) / NORDIVAL / SS-4BMRG-VCR / Mfc ranges 20sccm
(10) / NORDIVAL / SS-4-VCR-CP / Cap 1/4 females vcr
(14) / NORDIVAL / SS-600-2-2 / Male elbows 3/8 "swa 1/8" npt
(30) / NORDIVAL / SS-605-4 / Insert 3/8 swa - 1/4 swas
(1) / NORDIVAL / SS-FM6TA6PM6-24 / Flex line for batch hyd pumps
(2) / NORDIVAL / SS-T2-S-028-6ME / Steel pipes, gas line 2-meter pieces) 1/8
(12) / NORDIVAL / SS-T6M-S-1.0M-6 / Steel pipes, gas line 2-meter pieces) 1/4
(5) / - / U10-824810-010 / Amphenol back shells 97-3057-1010 farnell: 1912704
(5) / - / UCS-300-155 / Jennings variable capacitors 10-300pf vacuum 15 kV
(10) / RF Parts / VC2T-26.5 / Vacuum relays, 26.5v, threaded with nut
(3) / SODEMANN / VL-10-100-1200 / Variload gases spring dia 1: 10.00 dia 2: 23.00
(2) / - / YL VAC 25/6-E / Fomblin oil perfluoropolyther dry pumps.
还没有评论